For the last several years, a group has been trying to determine if there's a replacement for 100LL fuel, the gas on which much of the general aviation fleet runs. Today, they reached this conclusion: There isn't.
Here's the EAA news release:
June 27, 2012 - The Federal Aviation Administration (FAA) has published the final report and recommendations from the Unleaded Avgas Transition Aviation Rulemaking Committee (UAT ARC), a collaborative industry-government task force of key stakeholders representing aircraft and engine manufacturers, fuel producers and distributors, operator groups, aviation associations, the FAA, and the Environmental Protection Agency (EPA). This group studied the challenges associated with this transition and made recommendations necessary to facilitate the development and deployment of an unleaded fuel with the least impact on the existing piston-engine aircraft fleet. The transition to an unleaded fuel to replace 100LL may still be years away, but this report charts a roadmap that identifies the essential elements that need to be addressed to make this happen in a way that maintains safety and the role government should take to minimize the total cost.
The UAT ARC found that a "drop-in" unleaded replacement fuel that can be seamlessly deployed for the existing fleet of aircraft is not available and that alternative fuels require significant assessment to ensure safety. In addition, to date there is not a market-driven reason to move to a replacement fuel due to the limited size and specialty nature of avgas, combined with the safety, liability, and expense involved with a complex approval and deployment process. After its own review, the FAA "found the information and recommendations contained in the report to be very helpful in understanding the challenges of transitioning the piston engine-powered fleet to an unleaded avgas."
The UAT ARC provided several recommendations and detailed action plans necessary to facilitate the development and fleet-wide deployment of an unleaded avgas. The key recommendations include:
Implementation of a "Fuel Development Roadmap" that identifies specific milestones in the avgas development process and information needed to support assessment of the viability of candidate fuels in terms of impact on aircraft and production infrastructure and economic considerations.
Centralized testing of candidate unleaded fuels at the FAA William J. Hughes Technical Center funded by government and industry in-kind contributions to generate qualification and certification data.
Establishment of a collaborative industry-government initiative, referred to as the Piston Aviation Fuels Initiative (PAFI), to coordinate implementation of the UAT ARC recommendations to develop and deploy an unleaded avgas with the least impact on the existing piston-engine aircraft fleet.
If recommendations are fully implemented and funded, up to 10 unleaded aviation gasoline candidates could be evaluated. Within five years, the process would generate qualification and certification data to support fleet-wide certification of the most promising candidates. The actual transition to an unleaded avgas depends directly upon the level of impact upon the existing fleet and fuel production infrastructure. Therefore, the ARC recommendation includes up to six years for additional assessment and testing that may be necessary to facilitate a transition such as implementing approvals across the entire fleet, certification of modifications, and changes to fuel production infrastructure.
This Piston Aviation Fuels Initiative (PAFI) would rely on technical expertise from all stakeholders within industry and government. Centralized FAA testing of candidate fuels is essential to support an efficient fleet-wide qualification and certification, which is necessary for safety. Although this is just one part early in the process, this investment by the FAA will minimize the total cost of transition for both the FAA and industry. It also helps overcome significant market barriers that will facilitate industry investments needed toward the development of unleaded avgas and transition of the entire fleet of aircraft.
This is a joint statement from the general aviation industry members of the Avgas Coalition, which includes the Aircraft Owners and Pilots Association (AOPA), the Experimental Aircraft Association (EAA), the General Aviation Manufacturers Association (GAMA), the National Air Transportation Association (NATA), and the National Business Aviation Association (NBAA). This group applauds the FAA's leadership in establishing and participating in the UAT ARC and believes the recommendations are critically important to facilitating a transition to an unleaded avgas that works for the entire fleet. It will give owners and operators added confidence that the industry is on the right path to a solution.
The GA associations will continue to work with the FAA in developing, implementing, and funding an unleaded avgas plan that includes the key elements outlined in the ARC's report, which are necessary to facilitate the development and deployment of an unleaded avgas with least impact upon the existing piston-engine aircraft fleet.
View the full FAA Unleaded Avgas Transition Aviation Rulemaking Committee (UAT-ARC) report, which includes specific recommendations and detailed action plans.
By way of more background, I live blogged the discussion at Oshkosh two years ago about the issue.
Wednesday, June 27, 2012
Saturday, June 23, 2012
Flight Test Follies: The cross country
With N614EF's proving its engine is feeling fine in limited runs near Airlake Airport, it was time last evening to take her out for a walk around the test area, both to prove to me she's durable and also for me to get a sense of the flight test area.
And so we launched last night on roughly a 165-mile cross country trek to some of the larger airports on the southern and eastern borders of the test area. The GPS suggested I could do this in about an hour, but I planned to land at those airports and generally take my time.
I also need to check the calibration of both the Electronic Instruments' fuel gauge and the one that is included in the Grand Rapids Technologies EIS 4000 engine monitor. And I need to begin to focus on flying the ship a little more precisely than I have been. I haven't been concerning myself too much with headings and altitudes while I shake out the engine. That needs to change. I'm also weaning myself depending on two steam gauges -- altimeter and airspeed -- and onto the D100 electronic flight information system (EFIS).
With winds calm, and no pressure of a day-job blog to prepare for the next morning, it was a good evening to fly.
The first stop of all of our test flights is to get to the test area 16 miles away. The inspector (DAR) carved out a corridor to take me out of the Airlake Airport area, which spills into the test area somewhat east of Northfield, home of Carleton College, St. Olaf College, and Malt O Meal. The plane accelerated fine, the RPMs were good on the takeoff roll (2450) and the exhaust gas temperatures and cylinder head temperatures were below 400 on the climb. The #1 cylinder is still the one that is a little hotter than the others, but occasionally so is the #2. Those are both the front cylinders and both have the air dams in front of them called for in the Van's plans for the baffling. It's on my list to cut those down a little bit and see if it makes a difference. I must admit, though, I'm not embracing the chore of taking the baffles apart to make that happen.
Once in the test area, I headed southwest, toward Owatonna. It's a huge airport with one ridiculously long runway. There are some big manufacturers there, which accounts for the attention to its airport. I'm always mindful in flying into Owatonna, that a few years ago, eight people on a business jet from New Jersey lost their lives when they aborted a landing and stalled on the go-around.
One interesting thing as I approached the airport, which you can see in the picture below. The aft edge of the cowling seems to rise up above the top skin. I guess this seems typical what with all of the air pressure inside the cowling, although I do wonder if I lose some cooling ability in the situation.
I flew 2500' over the airport, flew out four miles or so, dumped 500 feet of altitude, then circled back for the standard 45-degree entry into the downwind leg of runway 30. There was a smaller runway in my direction of travel, but I don't like straight-in approaches and I enjoy practicing proper entries to traffic patterns.
As I circled back in, a Mooney took off, reported heading eastbound. We chatted for a second or two to establish he'd be no factor, as he was climbing to 3,000 feet. He was probably going over to Red Wing.
As usual, I set N614EF to blaze, making sure all the lights were on and the wig-wag function (thanks, Vertical Power, wish you'd kept producing the VP-50 and adding more goodies!) established to aid others in seeing my plane.
The landing was fine although it was a reminder that big wide, long runways make you feel you're lower than you really are. I didn't "plop" it onto the runway, but it wasn't my best landing. I heard a noise I hadn't heard before. Was it a nosewheel shimmy? Seems unlikely as I didn't hit the nosegear on landing, but maybe.
If you miss the first turnoff to the taxiway at Owatonna (which is the intersecting runway), you have a long trip to the next one. I missed the turnoff. It seemed like a mile and a half taxi (uphill) back to take off. Taxiing is a waste of fuel and money, and a reminder that it's time to step my landing approach speed down from 70 knots to 65 knots to lessen the ground roll distance after landing.
I was down to about 20 gallons or so -- half tanks -- but I had planned to fuel up in Dodge Center, the next stop. Most of the fuel at the airports on my route are much higher than what's being charged now at my home airport -- South Saint Paul ($5.12 a gallon). But I can't go there. I've been hauling fuel in portable cans from there, but that's not practical on this flight. Still, I brought some extra gas cans with me. At airport pumps, you prebuy either a fixed dollar amount, or a fixed number of gallons. There's no you-buy-only-what-you-need function in airport fuel pumps as with your local gas station.
The takeoff from Owatonna was fine, although I noticed -- as I did at Airlake -- that I drifted pretty far left on the takeoff roll. That's no mystery. An RV needs a lot of right rudder on takeoff to counter for the torque produced by the prop. I learned this when doing transition training in Tom Berge's RV, where I was executing flawless takeoffs. But up until recently, I was flying behind an under-powered airplane, and I'd let the skill deteriorate because the pull to the left was nowhere near as pronounced. Now I had something else to work on for this flight.
The cylinders hit 407 on climbout, still a little higher than I like, but nothing particularly serious. I lowered the nose a bit to level and they cooled to the 380 range as we crossed over downtown Owatonna, heading for Dodge Center.
Without wheel pants, gear leg and intersection fairings, the speed settled in around 130 knots, with me not wanting to push the engine more than 2450 RPM and about 23 inches of manifold pressure. I could comfortably lean the engine out to about 8 gallons of fuel per hour, though I mostly kept it full rich to help the engine break in.
On that front, I'm pretty sure this engine is broken in and the rings are seated. It still is using very little oil, and with no indication of oil consumption, there's no indication the rings aren't seated against the cylinder walls. So I'm pretty sure I can lean this thing out more at altitude and maybe spend less money on fuel.
Dodge Center, which sits southeast of Owatonna, is the southern boundary of my test area. I've never flown in there, but the airport sits on the prairie, surrounded by wind turbines. These are easily spied as I leveled off at 3200 feet (I'm using goofy altitudes for flying until that ZAON traffic alert system arrives). So is Rochester, which lies southeast of Dodge Center, and is in Class D (or maybe it's Class C) airspace.
You can barely see the turbines to the upper
I approached the airport a little from the southwest so I could make a 45-degree entry to runway 34. There was no traffic in the area and landing was uneventful except that the runway dips down and then goes up a hill. When it dips down, it takes some work to figure out where civilization -- and the fuel tanks -- are. It's a very steep grade to the top of the runway -- at least as runways go. But I found the tanks.
It was pretty darned quiet in Dodge Center.
Now it was time to do my calibration test, and pay for the privilege of doing so. Gas was $5.45 a gallon. The Electronic Instruments gauge said I had 17.5 gallons of fuel combined in tanks that hold a total of 42 gallons fuel. The Grand Rapids engine monitor said I had 11. I had previously calibrated the EI when I installed it, but I was still surprised to see how well it worked. I took on 24.5 gallons, and put the extra half gallon in one of the fuel jugs I'd taken along.
The engine monitor's FloScan unit has a configuration setting that you can use to adjust for the inaccuracies and I'll calculate how far off it was sometime this weekend and compensate for it in the unit. But it's good to know that when it was telling me I was using 12 gallons of fuel an hour, or leaning to 8 GPH, I was actually using less. Not a lot less, but less. Of the many things they don't tell you about this stage of building an airplane, this is one of the big ones: It takes a lot of gas -- and hence, a lot of money -- to haul a plane around the sky for 40 hours at high-power settings.
I taxied back down the hill, which they call a runway in Dodge Center, and then up another hill, which they call the other end of the runway in Dodge Center, and took off with full tanks (250 or so pounds of fuel) -- switching one to the other soon after takeoff so that no fuel would puke out of the fuel vents. At $5.45 a gallon, it's liquid gold.
I followed the GPS in the direction of Red Wing. Another thing I notice, the HSI function in the Dynon D100, which gets its information from my little portable Garmin 296, has quite a lag to it, so when you turn to a heading it indicates, you really have to let it catch up. I would like the GPS to be a little more visible to me (I have to lean over to see it, and it's a small screen for old eyes). I have an AirGizmo dock which turns it toward me, but it doesn't fit the standard cutout for the AirGizmo dock that simply installs it into the panel. That was a wasted $95. Anyone want it? For you, $75.
Evening was setting on the prairie of Minnesota...
Slowly, the prairie starts to give way to rolling hills. We're heading for bluff country along the Mississippi River...
and Red Wing...
The Red Wing airport is actually in Wisconsin, just over a beautiful river, running a little faster with recent rains, and soon to run a lot faster as the flash floods in Duluth this week make their way to this area sometime next week.
The winds were calm in Red Wing, so I made a crosswind entry to the pattern for runway 9 and landed perfectly, of course, taxiing back and immediately taking off again (a perfect takeoff, by the way, with lots of right rudder). I would have liked to have gotten out and stretched my legs a bit -- they have a nice pilot lounge in Red Wing -- but I thought I saw some weather moving in from the west and I didn't want to get caught there.
As it turned out, it wasn't weather so much as haze. A marine-type layer seemed to be forming over the city, so as I headed back west to the test-area entry point, I battled -- that might be too strong a word -- the visibility and the sun in my eyes to the northwest.
The cylinders were, again, a little hot -- 406 -- but nothing serious. I leaned out to 9 GPH but decided to go full rich. It's only money and it's not like N614EF didn't deserve a few luxuries, given the way she's treated me this week.
It took only 8 minutes to reach the test area entry corridor to Airlake. The problem is you can't follow the boundaries of the corridor and make a proper and safe 45-degree pattern entry for runway 30 at the airport, and it sounded like there was a little traffic in the area, and safety trumps rules, in my book.
So I headed over the top of Northfield, in order to put the airport more off my right wing, to turn and make a proper pattern entry, while losing altitude and speed.
Down below, I noticed, they were playing baseball under the lights on a delightful night.
I was five miles out on the 45 degree entry for runway 30, when I heard a Cessna report he was on an "eight mile final" on an instrument approach. Could I sneak in before him? Should I try? I lost more speed, did a couple of small "S" turns and dropped to pattern altitude just before I turned for the downwind. He was three miles out and, of course, traveling much slower than I was.
He was also, more than likely, renting that plane and was a student. It was a nice night, so I got on the radio and said I'd extend my downwind to allow the Cessna to land, even though I heard another plane a few miles behind me, heading our way for landing.
"I appreciate that," he said. "And we have you in sight," a testament to the beauty of two landing lights and a wig-wag system.
"No problem," I responded, "it's a beautiful night to fly."
Momentarily, I spied him on his final approach, passing off my left wing, so I turned "base" (perpendicular) to the runway, put out the rest of my flaps, reduced engine power and headed for a nice two-chirp landing just after the Cessna cleared the runway.
As I was approaching to land, I saw the Cardinal up above me and to the left, traversing the sky on which I'd just traveled. Everything was in order. The world, roiling at that moment if you were listening to the news, was perfect if you were flying an airplane.
Then the pilot of the Cardinal announced his position on downwind, paused for a moment, and then said with a bit of a sigh, "... you're right. It's a beautiful night to fly."
Friday, June 22, 2012
My other plane is a spacecraft
Smithsonian's Air & Space Magazine has a really interesting feature on what aircraft astronauts fly when they're done being astronauts.
This one looks a little familiar...
It's Dan Brandenstein's RV-7. I don't think he built it, though.
It's co-owner is listed as my old RV BBQ pal, Dana Overall.
That's Dana on the left at the 2008 (I think it was 2008) RV Builder's BBQ (along with Howard Kaney and Jeff Point)
You know, I kind of miss putting those BBQs together.
Anyway, here's the full article.
This one looks a little familiar...
It's Dan Brandenstein's RV-7. I don't think he built it, though.
It's co-owner is listed as my old RV BBQ pal, Dana Overall.
That's Dana on the left at the 2008 (I think it was 2008) RV Builder's BBQ (along with Howard Kaney and Jeff Point)
You know, I kind of miss putting those BBQs together.
Anyway, here's the full article.
Flight Test Follies: Time to stretch
As you know if you've been following this blog of late, I've been struggling with learning the engine of N614EF and figuring out rumbles and reduced power. Even when I reported a restoration of power after finding a slight blockage in the fuel injector on the #1 cylinder, people were warning me about too-high exhaust gas temperatures and higher-than-normal temperatures on the the #1 cylinder head.
Finding a little more blockage on the #1 injector led me to believe that whatever problem the engine was having, we've found the reason, but until you take it up into the air, you just don't know for sure.
So last night I took her up and, again, orbited the airport at 3,000 feet (actually 3,200 based on this article by my RV mentor, Doug Weiler).
I didn't have the engine monitor hooked up to my laptop so merely passing along observations as I remember them, I can report that I developed about 2450 RPM on the takeoff roll and, most important, all of the CHTs and EGTs were close to each other.
As I circled the airport, I had no problem developing 2500 RPM (I have the engine monitor set to show an alarm if I go beyond that), and the cylinder head temperatures were all within about 10 degrees of each other at about 373 in level flight. #1 was slightly higher, which I still blame on having the air dam in place to encourage more air to get to the back cylinders (3 & 4).
The exhaust gas temperatures were similarly fairly equal. I saw nothing close to the 1400 on the #1 I saw on takeoff (at 2350 RPM) the other day. #1 was still the coolest of the EGTs, but I'm still not convinced the probe is entirely accurate. I also think at this point, comparing EGTs can lead you in a wrong direction.
The plane is using very little oil -- almost none it seems -- which continues to baffle me. Theoretically, if the engine isn't broken in, it should be using a lot of oil. Is the engine broken in? I have no idea, but I'd like to think it is so I can throttle back and save some money.
After orbiting the field for 20 minutes or so, I headed southeast to lose altitude and at one point, got the plane up to about 150 knots indicated airspeed, which is pretty darned good (I think) considering there are no intersection fairings, gear leg fairings, or wheel pants on the plane at the moment.
At some point soon, I'm going to have to take the plane over to the gas pumps and bite the bullet and fill each tank to the brim, so I can fully calibrate the FlowScan fuel-flow meter and also check exactly how heavy the heavy wing is (it's much better than it was).
But I have a lot of confidence in the engine now, and it's time to take the plane out to the test area and do some serious flight-testing work to determine the entire airframe's performance ability.
Finding a little more blockage on the #1 injector led me to believe that whatever problem the engine was having, we've found the reason, but until you take it up into the air, you just don't know for sure.
So last night I took her up and, again, orbited the airport at 3,000 feet (actually 3,200 based on this article by my RV mentor, Doug Weiler).
I didn't have the engine monitor hooked up to my laptop so merely passing along observations as I remember them, I can report that I developed about 2450 RPM on the takeoff roll and, most important, all of the CHTs and EGTs were close to each other.
As I circled the airport, I had no problem developing 2500 RPM (I have the engine monitor set to show an alarm if I go beyond that), and the cylinder head temperatures were all within about 10 degrees of each other at about 373 in level flight. #1 was slightly higher, which I still blame on having the air dam in place to encourage more air to get to the back cylinders (3 & 4).
The exhaust gas temperatures were similarly fairly equal. I saw nothing close to the 1400 on the #1 I saw on takeoff (at 2350 RPM) the other day. #1 was still the coolest of the EGTs, but I'm still not convinced the probe is entirely accurate. I also think at this point, comparing EGTs can lead you in a wrong direction.
The plane is using very little oil -- almost none it seems -- which continues to baffle me. Theoretically, if the engine isn't broken in, it should be using a lot of oil. Is the engine broken in? I have no idea, but I'd like to think it is so I can throttle back and save some money.
After orbiting the field for 20 minutes or so, I headed southeast to lose altitude and at one point, got the plane up to about 150 knots indicated airspeed, which is pretty darned good (I think) considering there are no intersection fairings, gear leg fairings, or wheel pants on the plane at the moment.
At some point soon, I'm going to have to take the plane over to the gas pumps and bite the bullet and fill each tank to the brim, so I can fully calibrate the FlowScan fuel-flow meter and also check exactly how heavy the heavy wing is (it's much better than it was).
But I have a lot of confidence in the engine now, and it's time to take the plane out to the test area and do some serious flight-testing work to determine the entire airframe's performance ability.
Tuesday, June 19, 2012
Flight Test Follies: The drug test
It was pee-in-a-cup night for N614EF as the flight test period continues.
Although the plane performed much better once we removed crud from the #1 cylinder injector on Sunday, the exhaust gas temperature and the cylinder head temperature for the cylinder were higher than for other cylinders, indicating that perhaps the mixture was a little leaner in that cylinder than it should be.
So today I took the injection line off again and checked the injector again and, sure enough, there was a speck of dirt blocking things a bit; it wasn't as bad as what we pulled out of there on Sunday, but it was clearly enough to deprive the cylinder of all the fuel it needs to run efficiently and stay relatively cool.
You can see the small speck -- which looked like a flake of primer -- at the end of the safety wire I used to poke it out. You might have to click on the image to see it.
After that, I wanted to check all four lines to see if they were putting out a fairly equal amount of fuel. So I stuck some Dixie cups at each injector and flushed out the lines, dumped the fuel and then turned on the boost pump for 15 seconds.
Then I weighed each cup and found that each was within 1 gram or so. The last cup I weighed, the #4 cylinder, showed only 16 grams but I'm chocking this up to them being paper cups and some of the fuel leaking out of them in the time it took me to weigh the other three. Whatever, the #4 cylinder hasn't been much of a bother up to now.
So all that was left was to start the engine for a light look at things. It's too windy to do any flying. In about a 7 minute exercise, all four cylinder temperatures were within 4 or 5 degrees of each other -- that's a big difference from the last few months when #1 was noticeably hotter. And the number 1 exhaust gas temperatures were quite a bit below the other three. That's not much of a change.
We'll see if a flight later this week reveals any difference in temperatures but the engine is sounding better and better -- smoother -- to me than it has in quite awhile.
Although the plane performed much better once we removed crud from the #1 cylinder injector on Sunday, the exhaust gas temperature and the cylinder head temperature for the cylinder were higher than for other cylinders, indicating that perhaps the mixture was a little leaner in that cylinder than it should be.
So today I took the injection line off again and checked the injector again and, sure enough, there was a speck of dirt blocking things a bit; it wasn't as bad as what we pulled out of there on Sunday, but it was clearly enough to deprive the cylinder of all the fuel it needs to run efficiently and stay relatively cool.
You can see the small speck -- which looked like a flake of primer -- at the end of the safety wire I used to poke it out. You might have to click on the image to see it.
After that, I wanted to check all four lines to see if they were putting out a fairly equal amount of fuel. So I stuck some Dixie cups at each injector and flushed out the lines, dumped the fuel and then turned on the boost pump for 15 seconds.
Then I weighed each cup and found that each was within 1 gram or so. The last cup I weighed, the #4 cylinder, showed only 16 grams but I'm chocking this up to them being paper cups and some of the fuel leaking out of them in the time it took me to weigh the other three. Whatever, the #4 cylinder hasn't been much of a bother up to now.
So all that was left was to start the engine for a light look at things. It's too windy to do any flying. In about a 7 minute exercise, all four cylinder temperatures were within 4 or 5 degrees of each other -- that's a big difference from the last few months when #1 was noticeably hotter. And the number 1 exhaust gas temperatures were quite a bit below the other three. That's not much of a change.
We'll see if a flight later this week reveals any difference in temperatures but the engine is sounding better and better -- smoother -- to me than it has in quite awhile.
Sunday, June 17, 2012
Flight Test Follies: Let's see what you've got, baby
Although the first few hours of its life have been beset by some "inconsistencies," the good news about the flight testing of N614EF is that I know my plane.
I knew months ago that the engine didn't sound quite right, even though I'd only been in it for a few minutes when it did. Even when Tom Berge flew it down to Airlake a couple of weeks ago, there was something about the way it started that day that I didn't like.
The last week or so has also had me thinking there's more to this engine than it's given me so far and Friday afternoon's "hello, are you going to listen to me?" notification solidified that.
I spent most of Saturday afternoon trying to find the cause. I took the fuel servo off, cleaned it out and replaced gaskets where it mates to the engine and throttle/mixture cable brackets. I cleaned filters out, and yet I could find no cause of the engine's obvious problems.
Then Stein Bruch -- he's letting me use his hangar -- stopped by to chat about it. He didn't think it was an induction leak because it didn't present itself until well after the engine had warmed the other day, and we were fairly confident it was getting a good spark, and that left only the fuel system.
But the search came up empty until we tried the last thing we could try: the fuel injectors. They're the small nozzles at the top of each engine cylinder that inject the fuel into the cylinder for burning.
Sure enough, when we dismantled one and looked into the tiny nozzle, it appeared blocked. Stein used a small piece of safety wire to poke out something that appeared to be SuperFil fiberglass fill. How it got there, I haven't a clue. It couldn't have gotten past the filter screen on the fuel servo, which means it must have been in the hose that goes from the fuel servo up to the "spider." From there it travels by small stainless steel hoses to the fuel injectors and into the cylinders.
I spent Saturday night putting things back together and started it up in the dark. It sounded fine, better than it has -- more like the engine I remember. But, of course, you never know until you get in and take her up.
Well, she's breathing better, that's for sure.
It was fairly busy at the airport. There was a Father's Day fly-in at Stanton Airport, a few miles away, and it was a nice day. So I counted the planes in the pattern, including one apparently transitioning, I picked my spot, and off we went...and we went!
We left the earth with the engine showing 2354 RPM. The lowest exhaust gas temperature in the past -- the #1 -- was now the hottest. The exhaust gas temperatures on rotation were 1398/1191/1169/1190 and cylinder head temperatures were 363/314/322/324. The #1 cylinder was obviously burning bright, and I was thinking, "I've GOT to cut that air dam down to size to cool it down."
"Looking good, Collins," someone radioed as I climbed.
It was Warren Starkebaum, my best RV-building friend who flies out of Crystal. He's been building almost as long as I have. He and his wife were at Stanton and he flew over in his Cessna, just to see if I was around, when he saw me taxiing. He was the "transitioning" airplane I saw.
I announced on the frequency that I intended to climb to 3,000 feet over the airport (that sits at 960 feet) and I was there by the time I was partway down the downwind leg.
Looking across the sky, I saw Warren up there, too, even though I didn't have any idea it was Warren.
The engine was operating great, showing me a power I hadn't see before.
I leveled off at 3,200 and showed 1317/1217/1195/1219 EGT and the CHT on #1 had raced over 400 degrees. Not good. The rest of the cylinders were in the 370 degree range. Curiously, the engine alarm did not flash a warning, even though I had it set to flash at 426, as Tom Berge had said a week earlier. Manifold pressure was 25.8, and the engine was drinking at 16 gallons per hour. The outside air temperature at 3,200 feet was 78.
At the height of it, I got 2538 RPM, although I should've paid more attention to the cylinder head temperature and I'm still not sure why it wasn't flashing the alarm, but it didn't. When I finally noticed it, it was at 416 degrees. So I pointed the nose down and it cooled fine.
Fifteen seconds later, I had the CHTs at 389/338/339/317 in a descent, at 9.9 GPH, manifold pressure at 12.6, 26 psi fuel pressure, exhaust gas temperatures of 1122/ 1139/1115/1121 at 1943 RPM. Oil pressure was in the 80-85 range at full power and around 75 the rest of the time.
The oil temp never got above 190 and that was on final. Most of the time it was around 175, and when the cylinder head temperature on #1 was burning its hottest, the oil was only at about 169. I've got a big oil cooler on this thing. But am I thinking too much when I say this is, err... interesting?
The air temperature dropped to 72 and it wasn't hard to figure out why. A thunderstorm was approaching the field. I departed southeast (along the corridor to the test area), to drop down to pattern altitude for a 45 degree entry to runway 12. As I turned back to the airfield, an RV (yellow and white, painted like Van's RV-9), scooted across in front of me, just a few hundred feet below me, heading west. I assume he was coming out of Stanton, but I was in no position to see him until it was too late. I'm hoping he saw me. I've got to order the Zaon right now! (Observation: I tend to think the safest place to be if you're going to transition near an airport is OVER the airport, above pattern altitude. And also be on the airport frequency. Maybe this person has a good traffic alert system. I sure hope so.)
I made a perfect crosswind landing -- that's right, I said "perfect." I've made fabulous landings in this thing -- then saw Warren in the ramp area, motioned for him to follow me and we had a great chat about his RV project, his backyard project, and the fact Medtronic laid him off after 29 years.
"I'm anxious to build," I said, "just leave me the keys to the hangar."
He's a great guy and it was a great happenstance to have him and his lovely wife share in the flight, short as it was (about a half hour).
Clearly, I need to work on the cooling on that #1 cylinder and cut that baffle dam down a bit.I'm concerned about having the CHT be over 416 on the flight, but the plane has been using very little oil and a few A&P friends have suggested that the engine probably was "broken in" (the piston rings seated) during the test runs that Mattituck ran after its construction, or perhaps in the 5 1/2 hours of flights on it in the last few weeks.
It's hard to know -- other than oil consumption -- when to say "it's broken in," and I'd like to remain around the airport before I head off to the test area for speed tests etc. I'll try it again in a few days, perhaps after I drill off that air dam on the #1 cylinder.
I had also done a little work on the heavy wing. It's much better. Not perfect, but I haven't yet fully configured the plane for testing the heavy wing, either.
The stiff throttle cable turned out to be not as bad as feared. The throttle linkage itself is a little bit stiff, and a repositioned spacer on the linkage assembly made for just enough of an offset in the travel of the cable to make it move easier.
We're getting there.
Saturday, June 16, 2012
Flight Test Follies - Part Three
When you're inching your way through getting to know a new airplane, it's hard not to think about all those flight-test reports online in which the builder says "she flew like a dream, hands off!" And "no problems."
I think flight testing a homebuilt airplane is more complex than that and I like to think the reason we don't hear more about those less-happy-go-lucky situations is because the builder is trying to figure out what the hell is wrong with his/her baby. And maybe also kicking the cat.
N614EF has been fun to fly so far. There's still the matter of the heavy wing, but that's getting solved slowly. But, to me, I still think she's been trying to tell me that she's not entirely happy, I just haven't been able to pin it down.
As you know, if you've read this column recently, the static RPM was a little low and we struggled through timing the magneto and generally trying to figure out what's "a little low" and what's "typical for this engine/plane/prop combination."
I was just starting to accept the latter yesterday when I heard it. At least I think I heard it.
I was over the test area, and shooting a few pictures of some flash flooding below near Stanton, Minnesota, when I thought I heard a misfire. That sort of thing catches your attention real fast. But the engine smoothed right out and the engine instruments were all in the green. Maybe I was being hypersensitive.
That was yesterday morning and the rest of the flight went fine.
I made some minor adjustments in search of a lighter wing last evening and then took the plane up for a ride. The plane seemed a tad sluggish, but not overly so.
Now, the rest of this I'm pulling out of some engine data that I recorded on a laptop, but because the logging program for the Grand Rapids EIS 4000, err, stinks, it's a little incomplete. You can't actually SAVE the data to a file, so I've taken snapshots of the data.
On runup, there was a 10 RPM drop when operating on the Lightspeed electronic ignition, and about a 80-100 RPM drop when operating only on the magneto.
Accelerating down the runway, I was getting about 2298 RPM -- somewhat less than earlier in the day -- cylinder head temperatures were 359/357/363/348 and exhaust gas temperatures were 1294/1133/1112/1150.
The anomaly there is that the #1 CHT is usually the hottest -- I assumed it's because there's an air dam in front of it as specified in Van's baffle kit instructions -- and the #1 EGT is lowest; it's been a finnicky connection, and is on my list of things to rip out, reposition, and replace.
The temperature indication imbalance was the case right up to takeoff, too. The #1 EGT was more than 100 degrees lower than the rest of the cylinders. In 22 seconds during the runup, for example, the temperature (EGT) went from 1012 to 797. Then it went back up quickly. Again, I suspected the connectors were crappy.
Anyway, as I climbed, I was over 100 knots, oil temp 163, oil pressure 81, the fuel flow at about 14 gph (I should point out here that the FloScan has not been precisely calibrated, but that's probably pretty close. The manifold pressure was about 26.9 and the fuel pressure was steady at about 25.
I was about 4 miles southeast of the airport when someone called in that they were "southeast of the airport inbound" (for the love of God, people, would it kill you to indicate how FAR southeast of the airport you are?), so I increased my climb a bit.
I wasn't getting more than 2300 RPM in the climb but as I passed through 2500 AGL, it happened. The engine coughed. It got my attention. Again. This time it stayed rough.
My first reaction was to reduce RPM and think about what I'd just done to undo it. Other than climbing, I hadn't done anything. I stopped climbing. (Note: I'd also brought 20 gallons of AVGAS down from KSGS and dumped it in the tanks, but it checked out fine). The engine started running rough, but was manageable and sounded happier at reduced RPM of between 1800 and 1900 RPM. Boost pump on, fuel tank switched. No difference. Mag check. Operating. Lightspeed check. Operating.
As I immediately turned back toward the airport -- I was six miles out -- I had no trouble maintaining control and the plane was clearly able to stay aloft, but when I added power, it shuddered. I thought I heard popping noises though I couldn't confirm this. It sounded like a wing gap fairing piece of rubber might be hitting the side of the fuselage (it wasn't).
I am kicking myself that I didn't pull the alternate air source cable. If that had smoothed things out, that would've told me a LOT. And if it didn't smooth things out, I'd at least know there wasn't an obstruction around the air filter causing the woes.
I decided to stay at reduced power, entered the pattern and landed without incident. After turning off the runway, I doublechecked the ignition and both were operating. A static RPM check, however, revealed the engine could only generate 1800 RPM. I taxied back to the hangar, and shut it down.
I attempted to review all the engine data on the laptop, but it stopped recording that data right around the time the problem developed. I'm not reading much into this, however, because the monitor-to-computer setup is rinky dink and the serial-to-USB connection could've gotten loose. Plus, as I said, the EISLog program hates my Windows 7 laptop.
But I monitored those readings as the event was occurring and there was absolutely no evidence showing itself. And none of the engine monitor's alarms went off.
Pulling the top cowling did not reveal anything except a couple of drips on the bottom cowling. One point here: I've been amazed -- and a little concerned -- about how much oil the engine is NOT consuming. Since Tom Berge's test flight, I've added a half-quart of oil, resulting in oil on the belly. The engine has run for about 3-4 hours in that time, including an hour at 2400-2450 RPM on yesterday morning's flight.
Something is obviously wrong here, but what?
When he looked at the plane last weekend, Stein Bruch noticed the throttle cable was very stiff to operate. And, thinking about it, it seems to me it had gotten stiffer over the last two flights. A check earlier showed the throttle hitting the stops, but it's unclear whether this stiffness is in the cable itself, or the throttle on the fuel servo.
The other thing I noticed yesterday morning is that at 3500 feet -- when I tested it -- it takes VERY little leaning of the mixture to make the engine run rough. Very little -- less than a half inch of mixture travel. Is that a problem? I don't know, but it's different than most engines I've flown behind.
In fact, if I had to describe what the engine was doing, it would be most accurate to say "it sounds like what an engine sounds like when you lean it out too much."
The engine passed a fuel flow test last week when taken at the inlet to the fuel pump, but it appears another one is called for at the fuel servo.
Assuming all these numbers are correct, I'm going to focus on that servo, pull it off and see whether anything presents itself. Disconnected from the throttle cable (another one was already on order), does the throttle arm still move stiffly? If so, I'd guess that shows where the problem likely is. Is there some crap in there I couldn't find earlier? Is there a filter screen or anything somewhere in the servo I can pull off and check?
I also want to doublecheck how I mounted the throttle/mixture brackets. That's integrated with fuel servo installation. Should there have been another gasket in there? Did I not put it on, is there a leak there?
Air and fuel -- those are the two players in this since we know we've got good sparks and a timed ignition.
If today's probe doesn't reveal anything, I've got a problem. I've tapped out my own limited expertise, and the plane isn't at my home airport. I'll need an expert who makes housecalls.
I think flight testing a homebuilt airplane is more complex than that and I like to think the reason we don't hear more about those less-happy-go-lucky situations is because the builder is trying to figure out what the hell is wrong with his/her baby. And maybe also kicking the cat.
N614EF has been fun to fly so far. There's still the matter of the heavy wing, but that's getting solved slowly. But, to me, I still think she's been trying to tell me that she's not entirely happy, I just haven't been able to pin it down.
As you know, if you've read this column recently, the static RPM was a little low and we struggled through timing the magneto and generally trying to figure out what's "a little low" and what's "typical for this engine/plane/prop combination."
I was just starting to accept the latter yesterday when I heard it. At least I think I heard it.
I was over the test area, and shooting a few pictures of some flash flooding below near Stanton, Minnesota, when I thought I heard a misfire. That sort of thing catches your attention real fast. But the engine smoothed right out and the engine instruments were all in the green. Maybe I was being hypersensitive.
That was yesterday morning and the rest of the flight went fine.
I made some minor adjustments in search of a lighter wing last evening and then took the plane up for a ride. The plane seemed a tad sluggish, but not overly so.
Now, the rest of this I'm pulling out of some engine data that I recorded on a laptop, but because the logging program for the Grand Rapids EIS 4000, err, stinks, it's a little incomplete. You can't actually SAVE the data to a file, so I've taken snapshots of the data.
On runup, there was a 10 RPM drop when operating on the Lightspeed electronic ignition, and about a 80-100 RPM drop when operating only on the magneto.
Accelerating down the runway, I was getting about 2298 RPM -- somewhat less than earlier in the day -- cylinder head temperatures were 359/357/363/348 and exhaust gas temperatures were 1294/1133/1112/1150.
The anomaly there is that the #1 CHT is usually the hottest -- I assumed it's because there's an air dam in front of it as specified in Van's baffle kit instructions -- and the #1 EGT is lowest; it's been a finnicky connection, and is on my list of things to rip out, reposition, and replace.
The temperature indication imbalance was the case right up to takeoff, too. The #1 EGT was more than 100 degrees lower than the rest of the cylinders. In 22 seconds during the runup, for example, the temperature (EGT) went from 1012 to 797. Then it went back up quickly. Again, I suspected the connectors were crappy.
Anyway, as I climbed, I was over 100 knots, oil temp 163, oil pressure 81, the fuel flow at about 14 gph (I should point out here that the FloScan has not been precisely calibrated, but that's probably pretty close. The manifold pressure was about 26.9 and the fuel pressure was steady at about 25.
I was about 4 miles southeast of the airport when someone called in that they were "southeast of the airport inbound" (for the love of God, people, would it kill you to indicate how FAR southeast of the airport you are?), so I increased my climb a bit.
I wasn't getting more than 2300 RPM in the climb but as I passed through 2500 AGL, it happened. The engine coughed. It got my attention. Again. This time it stayed rough.
My first reaction was to reduce RPM and think about what I'd just done to undo it. Other than climbing, I hadn't done anything. I stopped climbing. (Note: I'd also brought 20 gallons of AVGAS down from KSGS and dumped it in the tanks, but it checked out fine). The engine started running rough, but was manageable and sounded happier at reduced RPM of between 1800 and 1900 RPM. Boost pump on, fuel tank switched. No difference. Mag check. Operating. Lightspeed check. Operating.
As I immediately turned back toward the airport -- I was six miles out -- I had no trouble maintaining control and the plane was clearly able to stay aloft, but when I added power, it shuddered. I thought I heard popping noises though I couldn't confirm this. It sounded like a wing gap fairing piece of rubber might be hitting the side of the fuselage (it wasn't).
I am kicking myself that I didn't pull the alternate air source cable. If that had smoothed things out, that would've told me a LOT. And if it didn't smooth things out, I'd at least know there wasn't an obstruction around the air filter causing the woes.
I decided to stay at reduced power, entered the pattern and landed without incident. After turning off the runway, I doublechecked the ignition and both were operating. A static RPM check, however, revealed the engine could only generate 1800 RPM. I taxied back to the hangar, and shut it down.
I attempted to review all the engine data on the laptop, but it stopped recording that data right around the time the problem developed. I'm not reading much into this, however, because the monitor-to-computer setup is rinky dink and the serial-to-USB connection could've gotten loose. Plus, as I said, the EISLog program hates my Windows 7 laptop.
But I monitored those readings as the event was occurring and there was absolutely no evidence showing itself. And none of the engine monitor's alarms went off.
Pulling the top cowling did not reveal anything except a couple of drips on the bottom cowling. One point here: I've been amazed -- and a little concerned -- about how much oil the engine is NOT consuming. Since Tom Berge's test flight, I've added a half-quart of oil, resulting in oil on the belly. The engine has run for about 3-4 hours in that time, including an hour at 2400-2450 RPM on yesterday morning's flight.
Something is obviously wrong here, but what?
When he looked at the plane last weekend, Stein Bruch noticed the throttle cable was very stiff to operate. And, thinking about it, it seems to me it had gotten stiffer over the last two flights. A check earlier showed the throttle hitting the stops, but it's unclear whether this stiffness is in the cable itself, or the throttle on the fuel servo.
The other thing I noticed yesterday morning is that at 3500 feet -- when I tested it -- it takes VERY little leaning of the mixture to make the engine run rough. Very little -- less than a half inch of mixture travel. Is that a problem? I don't know, but it's different than most engines I've flown behind.
In fact, if I had to describe what the engine was doing, it would be most accurate to say "it sounds like what an engine sounds like when you lean it out too much."
The engine passed a fuel flow test last week when taken at the inlet to the fuel pump, but it appears another one is called for at the fuel servo.
Assuming all these numbers are correct, I'm going to focus on that servo, pull it off and see whether anything presents itself. Disconnected from the throttle cable (another one was already on order), does the throttle arm still move stiffly? If so, I'd guess that shows where the problem likely is. Is there some crap in there I couldn't find earlier? Is there a filter screen or anything somewhere in the servo I can pull off and check?
I also want to doublecheck how I mounted the throttle/mixture brackets. That's integrated with fuel servo installation. Should there have been another gasket in there? Did I not put it on, is there a leak there?
Air and fuel -- those are the two players in this since we know we've got good sparks and a timed ignition.
If today's probe doesn't reveal anything, I've got a problem. I've tapped out my own limited expertise, and the plane isn't at my home airport. I'll need an expert who makes housecalls.
Tuesday, June 12, 2012
Flight test follies: Part Two
I admit to being more than a little bit bummed that the first test flight, flown by me, last week was cut short, but I can safely say a Second First Flight is pretty darned cool, too.
The gusty crosswind conditions abated at KLVN (Lakeville, MN) today,leaving only 7-10 mph winds mostly down the runway. And it was cool and dry. And the engine instruments were properly calibrated (thanks to Lars Pedersen who sent me the configuration for the fuel pressure on the Grand Rapids EIS 4000). And the engine purred like a kitten last night.
She wanted to fly. And so did I.
There was nothing about N614EF's performance today that didn't want me to give it a big hug. I had rigged up my laptop to take in the engine monitor data but if there's one thing on my wish list, it's a decent logging program for the EIS 4000 engine monitor instead of the cranky ones and, alas, I found out on returning that none of the data got recorded.
But the engine monitor is a big help since I got it configured to my liking. I've got the red light glowing until the oil temperature reaches 110 degrees, meaning it's ready to fly.
I have to use the memory to remember some of the readings but it seems to me the RPM was over 2300 racing down the runway, and it climbed easily at more than 90 knots -- perhaps even 100. I circled the field at 2500 feet a bit and then firewalled the throttle in level flight to see if it could develop 2700 RPM. Maybe it could; I couldn't. I just couldn't bring myself to do that to a new engine, so I throttled back as it was still developing RPM and going past 2500. I decided, for now, to be convinced: this engine can haul me around the sky just fine.
So I headed for the corridor out to the test area -- 26 miles away -- and did, in fact, notice a considerable wing heavy on the left side. Stein Bruch is pretty sure it's related to a twist in the elevators at their attach point and misrigged flaps. So at some point when I've nothing to do, I'll spin the rod end bearing around once or twice on one side, and once or twice the other way on the other flap rod-end bearing and see what happens.
I did a few steep turns and slow flight, and opted not to do any stalls today and concentrate instead of just getting to know her a bit and get a feel for things (memo to self: Change the placard on the trim knob, it's reversed, not that it won't become instinct in a day or two).
I mostly stayed around 120 knots, showing somewhere on the order of 19 and 20 MP, and keeping the RPM in the 2000 range, give or take.
And then, because I have to make a living, I headed back to Airlake Airport. There was traffic reported in multiple directions, but as usual on these sorts of days -- and many others -- I didn't see any of it. One of these days, I'm going to get a Zaon traffic alert system.
I practiced slowing her down, because everyone says that's the hardest thing to do with a 7A, and I didn't find that too difficult, and, after a few steep turns for kicks and because it's one unbelievably beautiful day in Minnesota, headed for a 45 degree entry to the downwind, stuck out the rest of my flaps, and landed at 70 knots against a slight crosswind.
During the descent, of course, I heard the voice of Tom Berge admonish, "don't raise the nose. Don't raise the nose," and kept my airspeed at 70 (gust factor included) and made the most unbelievably gorgeous landing of any I've ever made, maybe of any one anyone has ever made.
I smiled the RV grin, turned off the active runway, cleaned her up, and saw three or four guys standing outside a hangar. "Maybe they know me and maybe they're RVers," I thought. "Maybe they realized the significance of what they just saw," and as I taxied back to Stein's hangar, I saw them start to follow me.
I turned down the taxiway to the hangar, spun her around, and shut her down. "Should I wait for them to get here so I can properly acknowledge their cheers?" I thought. But it was getting hot under the canopy and I figured it was better to shut the system down and get her back in the hangar.
Which is good because they never showed up. They were heading for their cars and driving away, leaving me alone with an unbelievably wonderful airplane, and a grin.
This thing about not having to go to a clerk and write a check immediately after flying is going to take some getting used to.
The gusty crosswind conditions abated at KLVN (Lakeville, MN) today,leaving only 7-10 mph winds mostly down the runway. And it was cool and dry. And the engine instruments were properly calibrated (thanks to Lars Pedersen who sent me the configuration for the fuel pressure on the Grand Rapids EIS 4000). And the engine purred like a kitten last night.
She wanted to fly. And so did I.
There was nothing about N614EF's performance today that didn't want me to give it a big hug. I had rigged up my laptop to take in the engine monitor data but if there's one thing on my wish list, it's a decent logging program for the EIS 4000 engine monitor instead of the cranky ones and, alas, I found out on returning that none of the data got recorded.
But the engine monitor is a big help since I got it configured to my liking. I've got the red light glowing until the oil temperature reaches 110 degrees, meaning it's ready to fly.
I have to use the memory to remember some of the readings but it seems to me the RPM was over 2300 racing down the runway, and it climbed easily at more than 90 knots -- perhaps even 100. I circled the field at 2500 feet a bit and then firewalled the throttle in level flight to see if it could develop 2700 RPM. Maybe it could; I couldn't. I just couldn't bring myself to do that to a new engine, so I throttled back as it was still developing RPM and going past 2500. I decided, for now, to be convinced: this engine can haul me around the sky just fine.
So I headed for the corridor out to the test area -- 26 miles away -- and did, in fact, notice a considerable wing heavy on the left side. Stein Bruch is pretty sure it's related to a twist in the elevators at their attach point and misrigged flaps. So at some point when I've nothing to do, I'll spin the rod end bearing around once or twice on one side, and once or twice the other way on the other flap rod-end bearing and see what happens.
I did a few steep turns and slow flight, and opted not to do any stalls today and concentrate instead of just getting to know her a bit and get a feel for things (memo to self: Change the placard on the trim knob, it's reversed, not that it won't become instinct in a day or two).
I mostly stayed around 120 knots, showing somewhere on the order of 19 and 20 MP, and keeping the RPM in the 2000 range, give or take.
And then, because I have to make a living, I headed back to Airlake Airport. There was traffic reported in multiple directions, but as usual on these sorts of days -- and many others -- I didn't see any of it. One of these days, I'm going to get a Zaon traffic alert system.
I practiced slowing her down, because everyone says that's the hardest thing to do with a 7A, and I didn't find that too difficult, and, after a few steep turns for kicks and because it's one unbelievably beautiful day in Minnesota, headed for a 45 degree entry to the downwind, stuck out the rest of my flaps, and landed at 70 knots against a slight crosswind.
During the descent, of course, I heard the voice of Tom Berge admonish, "don't raise the nose. Don't raise the nose," and kept my airspeed at 70 (gust factor included) and made the most unbelievably gorgeous landing of any I've ever made, maybe of any one anyone has ever made.
I smiled the RV grin, turned off the active runway, cleaned her up, and saw three or four guys standing outside a hangar. "Maybe they know me and maybe they're RVers," I thought. "Maybe they realized the significance of what they just saw," and as I taxied back to Stein's hangar, I saw them start to follow me.
I turned down the taxiway to the hangar, spun her around, and shut her down. "Should I wait for them to get here so I can properly acknowledge their cheers?" I thought. But it was getting hot under the canopy and I figured it was better to shut the system down and get her back in the hangar.
Which is good because they never showed up. They were heading for their cars and driving away, leaving me alone with an unbelievably wonderful airplane, and a grin.
This thing about not having to go to a clerk and write a check immediately after flying is going to take some getting used to.
Sunday, June 10, 2012
Phase 1 Follies -- Part I
As crappy as yesterday was in terms of operating and diagnosing the performance of a new airplane, today was much different as some of the classiest people on Planet RV stepped forward with great assistance.
Unbeknownst to me, Stein Bruch stopped by the hangar -- did I mention he's letting me use his hangar during Phase 1 testing? -- and gave the plane a pretty complete onceover. He reported that the left magneto is fine, thought the plane was well built, and identified a few areas that might contribute to the heavy wing Tom Berge noted on the test flight a week ago. One was a twist in the elevator alignment, and the other was a slight flap misalignment from left to right.
There's nothing to be done about the former, but the latter can be adjusted. But first I'll fly and see the extent to which the wing is heavy. I adjusted the aileron alignment the other day. I didn't notice a heavy wing on that first flight I made, but I was busy with other stuff.
Stein also noted -- correctly -- that the throttle cable is very stiff. We looked for kinks -- Stein stopped by on his way home from work, too -- in it but didn't find anything. So I'm going to try another cable. Question: Who's got another cable they'd like to let me try out?
As I was driving down to Lakeville, Alex Peterson called (actually, he called earlier and I called him back) while he was driving up north. He offered to fly down Monday evening and look at the RPM problem. But, he said, "you may not have a problem. The engine may not be performing as poorly as you think." Indeed, I do want to get the RPM indicator cross-checked for accuracy.
We also talked about the manifold pressure problem and he suspected a bad gauge and explained to me what it should be reading.
What was especially illuminating was when Alex talked about the noises I heard. He indicated that when the wind is blowing from a certain direction, he gets a "popping" sound from the air vent ports on the side of the fuselage. What he described fit perfectly with what I was hearing yesterday and probably wasn't backfiring at all.
Anyway, I tackled the manifold pressure problem first in an all day/night session this afternoon/tonight and found that I had failed to properly configure the engine monitor. I was supposed to enter some code that was on the Grand Rapids EIS 4000 manifold pressure box into the engine monitor. Once I did that, the MP indication on the monitor with the engine off read the barometric pressure indicated when I set the barometer to zero. That was a big one out of the way and means the manifold pressure problem I had was not an engine problem. Oh, I also blew out the manifold pressure lines and they were fine.
I also realized that the fuel pressure alarm that went off while climbing out of the pattern yesterday was not a fuel pressure alarm at all; it was a fuel flow alarm. I had configured the engine monitor to indicate an alarm whenever the fuel flow exceeded 19 gph. It was supposed to alert me to a leak in the system, but the FloScan module hasn't been calibrated yet so it was a worthless alarm. So, again, what I thought was an engine problem was not.
I took the filtered air box off and looked at the throttle plate to confirm that it opens complete. It does. Reinstalled the airbox and moved on.
I wanted to remove the fuel filter on the high pressure fuel pump but I didn't get around to it. However, I did repeat the fuel flow test by running the boost pump and pumping fuel into a five-gallon container at the fuel servo. It came out to about 43 gallons per hour, which pretty well matched the FloScan fuel flow indicator on the engine monitor. So all was good there. That number is actually better than it was when I ran a similar test a summer ago.
As far as the oil, I'm pretty sure now the oil was coming out of the breather tube, so I wiped up what I could and reinstalled the cowling, pulled the plane out, and hooked up my laptop to the engine monitor serial output, started the engine and went about seeing where things stood.
Here are some of the things I found, in no order of importance:
-- The Lightspeed tach reading and the manifold tach reading matched. I got about a 100 RPM drop when operating only on the mag. That's about 40 more than yesterday. I really should've leaned out the engine and cleaned some carbon, but I didn't. I got about a 20 RPM drop operating only on the the Lightspeed.
-- On runup, the static RPM reading was about 2020. About 120 more than I got yesterday,and about 90 less than what Tom Berge recorded last Sunday.
-- Fuel pressure was reading 36 with the boost pump on.
-- I took the runway and accelerated. I did not hear the infamous "noises" and developed 2105 indicated RPM (and increasing) when I pulled power when I reached 41 knots. It appeared to accelerate fine. It was a lovely night. If not for the operating limitations,I might have considered going flying.
-- On that run, EGTs were: 1143/1086/1062/1094
Cylinder temps were: 354/318/325/320
Outside air temperature: 80
Fuel flow: 12.9 GPH
Manifold pressure: 28.5
Fuel pressure: 36
Oil pressure: 81
Oil temp: 149
Total time from throttle forward to throttle back: 9 seconds
I taxied off the runway and back and tried it again. On the next run, I was at 2120 RPM when I shut down at 43 knots.
-- On that run, EGTs were: 1131/1085/1072/1103
Cylinder temps were: 346/302/313/315
Outside air temperature: 80
Fuel flow: 17.1 GPH
Manifold pressure: 28.4
Fuel pressure: 36
Oil pressure: 81
Oil temp: 164
Total time from throttle forward to throttle back: 10 seconds
During taxi back to the hangar:
Fuel flow: 5.7
Fuel pressure: 38 (left the boost pump on)
Manifold pressure: 13.3
It took 846 RPM to feed 14 volts (strobes, all lights, and all systems on)
I did try to use the GRT-recommended system of checking the RPM by trying to "freeze" the propeller at 600 RPM with a 60hz (or is it Mz, I forget) light in the background and I could not get it to do that at any number of RPM settings. I'll have to find an optical tachometer somewhere.
Total testing time: 21 minutes 33 seconds.
I did not notice any immediate pools of oil in the bottom cowling or around the breather tube.
I feel pretty good about these numbers. The static RPM is still a little low, but as I said, we need to doublecheck the tach readings.
If anyone wants the spreadsheet with all of the numbers, just holler.
Unbeknownst to me, Stein Bruch stopped by the hangar -- did I mention he's letting me use his hangar during Phase 1 testing? -- and gave the plane a pretty complete onceover. He reported that the left magneto is fine, thought the plane was well built, and identified a few areas that might contribute to the heavy wing Tom Berge noted on the test flight a week ago. One was a twist in the elevator alignment, and the other was a slight flap misalignment from left to right.
There's nothing to be done about the former, but the latter can be adjusted. But first I'll fly and see the extent to which the wing is heavy. I adjusted the aileron alignment the other day. I didn't notice a heavy wing on that first flight I made, but I was busy with other stuff.
Stein also noted -- correctly -- that the throttle cable is very stiff. We looked for kinks -- Stein stopped by on his way home from work, too -- in it but didn't find anything. So I'm going to try another cable. Question: Who's got another cable they'd like to let me try out?
As I was driving down to Lakeville, Alex Peterson called (actually, he called earlier and I called him back) while he was driving up north. He offered to fly down Monday evening and look at the RPM problem. But, he said, "you may not have a problem. The engine may not be performing as poorly as you think." Indeed, I do want to get the RPM indicator cross-checked for accuracy.
We also talked about the manifold pressure problem and he suspected a bad gauge and explained to me what it should be reading.
What was especially illuminating was when Alex talked about the noises I heard. He indicated that when the wind is blowing from a certain direction, he gets a "popping" sound from the air vent ports on the side of the fuselage. What he described fit perfectly with what I was hearing yesterday and probably wasn't backfiring at all.
Anyway, I tackled the manifold pressure problem first in an all day/night session this afternoon/tonight and found that I had failed to properly configure the engine monitor. I was supposed to enter some code that was on the Grand Rapids EIS 4000 manifold pressure box into the engine monitor. Once I did that, the MP indication on the monitor with the engine off read the barometric pressure indicated when I set the barometer to zero. That was a big one out of the way and means the manifold pressure problem I had was not an engine problem. Oh, I also blew out the manifold pressure lines and they were fine.
I also realized that the fuel pressure alarm that went off while climbing out of the pattern yesterday was not a fuel pressure alarm at all; it was a fuel flow alarm. I had configured the engine monitor to indicate an alarm whenever the fuel flow exceeded 19 gph. It was supposed to alert me to a leak in the system, but the FloScan module hasn't been calibrated yet so it was a worthless alarm. So, again, what I thought was an engine problem was not.
I took the filtered air box off and looked at the throttle plate to confirm that it opens complete. It does. Reinstalled the airbox and moved on.
I wanted to remove the fuel filter on the high pressure fuel pump but I didn't get around to it. However, I did repeat the fuel flow test by running the boost pump and pumping fuel into a five-gallon container at the fuel servo. It came out to about 43 gallons per hour, which pretty well matched the FloScan fuel flow indicator on the engine monitor. So all was good there. That number is actually better than it was when I ran a similar test a summer ago.
As far as the oil, I'm pretty sure now the oil was coming out of the breather tube, so I wiped up what I could and reinstalled the cowling, pulled the plane out, and hooked up my laptop to the engine monitor serial output, started the engine and went about seeing where things stood.
Here are some of the things I found, in no order of importance:
-- The Lightspeed tach reading and the manifold tach reading matched. I got about a 100 RPM drop when operating only on the mag. That's about 40 more than yesterday. I really should've leaned out the engine and cleaned some carbon, but I didn't. I got about a 20 RPM drop operating only on the the Lightspeed.
-- On runup, the static RPM reading was about 2020. About 120 more than I got yesterday,and about 90 less than what Tom Berge recorded last Sunday.
-- Fuel pressure was reading 36 with the boost pump on.
-- I took the runway and accelerated. I did not hear the infamous "noises" and developed 2105 indicated RPM (and increasing) when I pulled power when I reached 41 knots. It appeared to accelerate fine. It was a lovely night. If not for the operating limitations,I might have considered going flying.
-- On that run, EGTs were: 1143/1086/1062/1094
Cylinder temps were: 354/318/325/320
Outside air temperature: 80
Fuel flow: 12.9 GPH
Manifold pressure: 28.5
Fuel pressure: 36
Oil pressure: 81
Oil temp: 149
Total time from throttle forward to throttle back: 9 seconds
I taxied off the runway and back and tried it again. On the next run, I was at 2120 RPM when I shut down at 43 knots.
-- On that run, EGTs were: 1131/1085/1072/1103
Cylinder temps were: 346/302/313/315
Outside air temperature: 80
Fuel flow: 17.1 GPH
Manifold pressure: 28.4
Fuel pressure: 36
Oil pressure: 81
Oil temp: 164
Total time from throttle forward to throttle back: 10 seconds
During taxi back to the hangar:
Fuel flow: 5.7
Fuel pressure: 38 (left the boost pump on)
Manifold pressure: 13.3
It took 846 RPM to feed 14 volts (strobes, all lights, and all systems on)
I did try to use the GRT-recommended system of checking the RPM by trying to "freeze" the propeller at 600 RPM with a 60hz (or is it Mz, I forget) light in the background and I could not get it to do that at any number of RPM settings. I'll have to find an optical tachometer somewhere.
Total testing time: 21 minutes 33 seconds.
I did not notice any immediate pools of oil in the bottom cowling or around the breather tube.
I feel pretty good about these numbers. The static RPM is still a little low, but as I said, we need to doublecheck the tach readings.
If anyone wants the spreadsheet with all of the numbers, just holler.
Friday, June 8, 2012
Test pilot tales
This morning, I took N614EF up for our first trip together and, as she's been for the 11 years we've been married, it wasn't simple. I am, of course, now into the test-pilot stage and I take these things pretty seriously; there's no time to be distracted by deep thoughts of journeys and self-satisfaction -- that's what Sunday was for. There's work to be done.
I can't say it was a particularly enjoyable half hour of work, because I haven't yet accepted the reality that things are going to go wrong and I'm not going to know what to do about them until I learn what to do about them, pretty much like the previous 11 years.
The weather said the winds were 3 knots this morning at Airlake Airport, but like previous times I've arrived, I found different weather conditions -- slightly windier and a little gustier. That's when I realized the AWOS system at Lakeville sucks and they haven't bothered to add a NOTAM or make an announcement to the effect of, "everything we just told you is mostly BS." But it was manageable, so a flying we would go.
The one thing nobody has told me -- maybe the only thing nobody has told me -- is that the plane makes some interesting sounds -- unfamiliar sounds -- on takeoff. Or at least, mine does.
The mag checked showed a drop of about 60 when I shut it down, leaving only the electronic ignition on (Updated correction: This is wrong. It should have said the drop was when I was operating only on the mag). That's more than I've seen drop in the few times I've started the engine, but it's not significantly lower. Still, it was different, just different enough to get in my head.
I could only get 1900 RPM on a static RPM check, lower than the 2150 Tom Berge reported last Sunday, and lower than the 2300 it should be. People have suggested the RPM would go up once the plane was moving so I attempted a takeoff and aborted it fairly quickly. The plane was making noises and, frankly, I couldn't tell if it was engine noises or airframe noises. It could have been backfiring or the engine could have been missing. I seriously don't know; I still don't know. I didn't have anybody standing nearby to tell me.
I removed my headphones to listen but I honestly couldn't tell what I was hearing because, for one thing, I've not been in this position before and I have nothing to compare things to.
I taxied back to the runup area and tried it again and did not detect any particular noises (the RPM hadn't changed). So I took the active runway and took off and, again, found the noise quite distracting, especially considering the fact I had it in my head the plane wasn't developing full power. But it was developing enough power to get airborne and so we did.
On turning downwind, a warning light cane on the engine monitor, showing a fuel pressure of 19 psi. The operating manual for the engine does not list a minimum fuel pressure, and it registered 37 psi on the ground. So I'm assuming the pressure is reduced because the engine is taking a big drink of juice during takeoff that it's not taking when taxiing. But after reaching pattern altitude, I switched tanks anyway.
I started heading for the test area but was fairly glued to some of the numbers I was seeing. I was at about 90 knots, 2,300 feet, and notice the manifold pressure wasn't going higher than 19 (altimeter 29.91, temp 77 FP prop 85 pitch). Cylinder temperatures were all in the green, though the hottest was the #1 cylinder. Curiously, the lowest exhaust gas temperature was also on the #1. I wish I hadn't followed Van's instructions and riveted the #1 cylinder air dam on the baffle.
Keep going? Or return for landing.
I went out five miles and then circled back to join a downwind for landing, which -- considering the winds had now come up -- wasn't that great. Wasn't horrible, it just wasn't up to par for me.
My left brake problems seem to have dissipated but now the right brake seems to be sticking a bit. I'm going to take that apart and clean it and retorque it, as I did the left one.
Back in the hangar, I pulled the top cowling off and noticed a fairly large amount of oil on the bottom cowling "floor." I now engines spew oil, but one problem is -- like the noises -- I have no benchmark to know what's a problem and what's not. Still, this seemed significant to me.
I noticed a little "spray" of oil on the back side of the baffle, just below the oil cooler.
But I couldn't quite find the source. I didn't see anything on the cooler itself to warrant concern, and both connections to it seemed solid. A hint of fuel lube was still around the base of the steel fittings and there was no drips at the connection with the hoses.
I did find a drop on a couple of the bolts at the base of the fuel pump...
I found some oil around what I presume to be drain plugs -- one safetied, the other is a hex nut. But is it coming from here? I don't know.
Looking closer, I can see oil around the sump bolts. By the way, you may find it more helpful to click the image and see the bigger version.
Kind of a dark, oily soot on top of the filtered air box. As long as I was here, I doublechecked to make sure there was no blockage of the filter. There wasn't.
At the front of the engine, you can see a drop of oil near the bracket for the prop oil line (plumbed but not used). Again, it's at the split of the engine case.
And you can't see it here but there appeared to be a small drip at the hose connection to the fitting for the oil cooler return to the engine (or maybe it's from the engine, I forget).
I also noticed oil on the sump bolts that are used to hold the hangars for the exhaust.
I'm pretty sure we're looking at two separate issues here. The oil situation is, perhaps, a matter of just tightening stuff, unless I'm missing something.
The engine power situation is an entirely different one. Frankly, I've stopped trusting that left magneto. I don't know whether that has anything to do with; I just don't trust it.
I inspected the rest of the engine for any telltale signs and didn't see anything, but then again, I don't really have any knowledge of a systematic way of working my way through analyzing what's going on here.
I do wish I'd hooked up the computer to gather the engine readings for later analysis, but I didn't bring it with me.
It's supposed to be a pretty crappy weekend so flying is probably out of the question, but a crow hop or two is possibly doable. If you've got a good set of ears and a little bit of knowledge about engines, how about standing by and listening from the outside of the plane?
(Update here)
Sunday, June 3, 2012
"I built that"
Just 11 days shy of the wedding anniversary for which it's numbered, N614EF became an airplane today when it flew under the tutelage of test pilot Tom Berge. June 14, 1942 was my parents' -- Eileen and Fred -- wedding date and this year would be the 70th anniversary. There's very little about this plane that doesn't incorporate almost everyone I know. Even a piece of carpet in the workshop was made by my grandmother, who died in 1986, years before I even contemplated the project. And, as you probably know, the signatures of people who helped or inspired dot the innards of the plane.
Before my Dad died, our few phone conversations always ended with, "you be careful in that thing." And I recalled that last week when I finally decided that the first flight should be done by the best pilot I could find, not only for the safety of whomever is flying the plane, but for the people in the houses surrounding this city airport.
I didn't miss out on anything. Standing next to my wife of (nearly) 30 years to watch the plane we built while our kids grew was about as good as it gets.
When I started this project 11 years ago, I wanted to end up with two things: (1) An airplane and (2) The same person next to me who was next to me when we started. By the way, that's not in order. What I got out of it that I didn't anticipate was a great number of friends I met along the way, managing to keep most of them.
When I reached Airlake Airport some time after Tom touched down, he stuck out his hand and said, "Congratulations, you have a nice airplane."
The only major items were a heavy left wing -- which is normal and can be fixed relatively easily, and a balky left brake, which I'd already expected.
There are many people to thank for this, which is why I'm not going to attempt to do it now.
I still have some transition training to do before I fly it, but that'll happen within the next few weeks, maybe on June 14th.
Meanwhile, today was a big day. My son, Patrick, turned 24.
(Photo: Julia Schrenkler)
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