Flight Testing

03/20/2005: Re-assembly.

And so a new chapter begins!

Let me start off by saying this – there are a hell of a lot of screws holding down all these access covers. I have removed (or, more accurately, never installed) all of the access covers, floor pans, and baggage area panels for the purpose of the airworthiness inspection. Now, putting all of these things in place and tightening them down is quite a task. I am finding a few items where screw holes no longer line up, and nutplates that are now at at a funny angle that prevents the screws from grabbing the threads. A few of the ribs have been bent slightly due to my having to crawl around and do things under the panel or back in the tail cone.

But, things are coming together. In another couple of days, everything should be tightly assembled and ready to go for first flight.

03/27/2005: First Flight!

Please note in the following descriptions, my airpseed indicator is not calibrated against any standard at this point, so all speeds are as indicated, and may not be accurate.

On Saturday (3/26), I performed several high speed taxi tests on the runway at Glendale. This was the first serious taxi operation that I have done, and while heading out to the runway, I noticed the right brake dragging quite a bit. I decided to make a medium speed pass and of course, the airplane drifted to the right quite a bit.

Back at the hangar, I took a close look at the brakes and decided it would be best to add another shim on both sides to open them up a bit. The effect was immediately noticeable, especially when pushing the plane around in and out of the hangar.

The next high speed taxi on the runway I brought it up to 40 KIAS. At that speed, the controls began to really be effective. I could feel the roll tendencies as I moved the ailerons left and right, and I could feel the pitch and yaw from the tail movements. Tracking was straight. I did notice quite a bit of shimmy, and this was later confirmed to be the nose wheel moving back and forth; a somewhat common RV problem.

I taxied back for the third and final high speed run. This time I got it up to about 45 KIAS. It did start to feel light and floaty, but I pulled the power before the nose got up.

Today, March 27, 2005 at approximately 9am Arizona time, I fired up the Eggenfellner Subaru and taxied out to the runway. I called Glendale ground and told them I would like to circle above the airport, then if all was looking good, proceed over to Luke AFB and do some airwork (when Luke is closed, their airspace becomes class G [Edit:  This is no longer true.]).

Taxi out was straight, and temps started coming up to normal. I did a brief run up and triple checked all the control movements and the backup electrical system. I was ready to go.

I taxied up the hold short line, got my clearance and drove up onto the centerline. I held the brakes on a bit while I pushed the throttle in, and when I let loose, the acceleration was amazing. The nosewheel came up very quickly and I was off the runway in about 250 feet. A quick wing waggle confirmed the controls were correct and everything was stable, so I bored a hole in the sky. I let it come up at 90 KIAS and was at 2600 MSL before being over the other end of the 7000 foot runway (KGEU is at about 1000 MSL).

I proceeded to fly a racetrack directly above the airfield, throttling back and flying at about 110 KIAS. After several orbits, the temperatures seemed to be rock solid, never going above 195F for oil and coolant. The outside air temperature was about 50F. I called the tower and let them know I was proceeding to the west over Luke AFB to do some airwork.

I opened the throttle a little bit and brought the speed up to 120 KIAS for the short run over to Luke. I climbed to about 4000 MSL and did some clearing turns, then did some slow flight. Clean stall was at 51 KIAS, and full flap stall was 43 KIAS.

At this point, I proceeded back towards Glendale at a leisurely 90 KIAS and requested a right crosswind entry back into the pattern at 2100 MSL.

I flew the approach a little hot at about 75 KIAS since the airspeed is not calibrated. Here is where things went a tad awry, though. My high wing Cessna 172 training kicked in, so I dropped full flaps. Over the threshold, I chopped the power expecting a little float time, and proceeded to plummet towards the runway. I yanked back on the stick to get the nose up and the bottom dropped out at about 2 feet AGL. The bounce wasn’t too high, but it was enough to be embarrassing. I added some power and kept the nose up for a second, much better landing about 25 feet further down the runway.

And that’s it! I taxied back to the hangar and let things cool down before pulling the top cowl off. There appear to be no leaks anywhere, and everything is still bolted on that was there before takeoff, so that is a good thing.

The engine and aircraft performed flawlessly. The left wing is only very slightly heavy, and only requires slight stick pressure to stay level. No yaw problems at all. The engine ran absolutely perfectly with not one hiccup through all RPM ranges. The MT prop also performed well. All in all, a resounding success.

04/18/2005: Speed tests.

8.3 flight hours: The engine is running strong, and I have no major squawks.

There was only one minor problem that needed fixing. The tank sump drains had drip-drip leaks, so I had to pull them and clean them. Some debris got under the o-ring which prevented them from sealing.

I pulled the cowl and double checked everything again. No leaks, no rubbing parts, no obvious issues. While I had the cowl off, I also pulled the gascolator and cleaned the filter. Just a little sand or something in it. Probably that lousy auto gas I was using during testing.

I have been going through a fairly conservative test plan, collecting data and figuring out the flight characteristics of my plane. Last week, I just had to put the fairings on and do some speed tests. So, my all white baby now has green legs with blue spots of body filler.

So, what are the numbers?
* See updated numbers with Gen3 at bottom of page.

Four Way GPS Tests
ALT MAP RPM OAT GS, KTS GS, MPH
5,500 25.28 1,700 56.50 119.50 137.52
5,500 24.78 2,000 54.50 129.75 149.32
5,500 24.55 2,400 55.00 141.00 162.26
5,500 24.50 2,700 55.00 144.00 165.72
8,000 22.70 1,700 64.00 119.25 137.23
8,000 22.70 2,000 64.00 129.00 148.45
8,000 22.30 2,400 64.00 139.25 160.25
8,000 22.23 2,700 64.00 141.75 163.13
10,500 20.40 1,700 53.00 117.25 134.93
10,500 20.40 2,000 52.00 130.00 149.60
10,500 20.40 2,400 52.25 135.50 155.93
10,500 20.35 2,700 54.00 138.50 159.39

Each entry is the average of four legs in cardinal compass headings. The speeds are GPS ground speed.

After doing another couple of drop tests on the landings, I decided to change my strategy a bit before people start calling me a Navy pilot or something (Yea, yea, I got the second wire… ha ha ha very funny).

It had been my understanding that one ought to run the prop at high RPM for landing. However, my thinking is that the prop is absorbing too much of that forward energy to keep spinning at a high rate. So, I started to bring the prop control back to 1900 RPM for landing, and what do you know, its a greaser every time.

I was concerned about delay getting the prop to high RPM in the event of a go-around. Interestingly, I keep finding ways to time my landings with the busiest possible traffic at Glendale, so I have had to do two go-arounds due to people not clearing the active runway fast enough for the controller to be comfortable.

The reality is that not only will the engine provide enough power to climb decently at any RPM, but the pitch is not far from where it should be anyway, so delay is negligible. This aint your daddy’s C-172.

Having the camcorder on a tripod strapped into the baggage compartment has been a great help. I can aim it right at the instrument panel and capture any details that I might miss while looking out for traffic. I also have a small remote microphone that I place inside the earcup of my headset to capture the audio off the radio and intercom. This is ideal since I can simply speak the data I need and write it down later. Looking down at a clipboard and writing during some of these tests is not only a hassle, but not so wise. After waving to the KC-135 drivers on Saturday while passing through 7000, my next radio call was to Luke AFB approach requesting traffic advisories. Every extra pair of eyes helps, and the controllers at Luke are very helpful.

05/09/2005: Endurance testing.

I did a few more flights to test the NAV radio, compass and Dynon. Basically I did a long cross country around the southern perimeter of my test box by navigating the VORs. Using a portable GPS to verify heading/track, I flew two flights of over 250nm each. It was also a good endurance test, not only for the plane, but to see how well I could manage things in the cabin during a long flight. Fortuntately everything seems to be working well.

There is only one thing that is bugging me, which is that the engine RPM will wander a bit – usually +/- 50 to 100 RPM. Not sure why; possibly the prop is hunting for a speed. Impossible to tell at this point.

06/15/2005: Beat the Heat.

The good news is – we got a “cool” wave here in Arizona for a few weeks, and I managed to fly off the 40 hour Phase 1 test time! And just in time too, because the temperatures have been climbing above 100 this past week. From here to the end of Hot, what little flying there is to be done will be in the very early morning.

Regarding the “prop hunting” problem mentioned above – I think this is a non-problem. What I have found after flying a few hours is that the prop RPM is sensitive to a lot of things. The first thing I discovered was the throttle tends to not stay where set unless the friction lock is used. Silly as it sounds, I caught myself a few times wondering why I was losing power in a climb, only to find that the throttle came out an inch or two.

The second thing I found was that until I got to about 20 hours or so, I really was not flying in the most stable manner possible. Aircraft pitch fluctuations affect the prop, and since the prop pitch adjustment is relatively slow, the RPM will appear to fluctuate quite a bit. Flying in dead calm air at 7500 feet shows that there is actually very little RPM fluctuation.

Speaking of heat, the engine temperatures have been well within nominal ranges. Even at 90F on the ground, it takes an effort to get the coolant up to 225F. A long, steep climb will raise the temps, but leveling out to get some airflow over the radiators brings them back down. Typical 1900 RPM cruise with 75F OAT at altitude yields 180F coolant, 185F oil. Higher cruise at 2300 or so brings coolant up to 195F.

One problem that I just discovered is a leaky brake line fitting. That will have to be fixed, but unfortunately, the leaky fitting is the one inside the cabin at the gear weldment. If torquing the fitting down a bit doesn’t help, that line may get replaced by a braided steel hose.

There are some other minor convenience issues, but certainly nothing affecting airworthiness or safety. All in all, everything has been performing more or less as expected. A little more top end speed is always nice to have, but for now, I will be enjoying what I have.

07/10/2005: Go faster fairings and a trip.

As you can see from the new pic on the intro page, I got the fairings and wheel pants back from the paint shop, and they look great! Unfortunately, I may have to refinish the rest of the airplane to match the high quality pro paint job… 🙂

Took it up for an hour and was amazed at the difference. I picked up a fairly solid 10kts indicated. YES, the fairings and pants make a BIG difference!!

Outside temp leaving GEU was 92F. Climbout really pushed the temps to the upper edge of the envelope. I may have to make a few mods to increase my margin of comfort. At 7,500+ however, OAT went down to 59F, and cooling was the last thing on my mind.

Can’t wait for the next flight!

09/03/2005: Squawks and hawks.

Someday I will put all the test data up here and start another page for post-test phase flying. Until then…

Did my longest ever straight line distance cross country on August 20. Flew to Brown Field in San Diego, CA to visit the EAA Chapter 14 folks. What an awesome trip. Just over 2 hours flight time got us there.

Later in the day, I relocated the plane to Carlsbad/Palomar Airport on the north side of San Diego. I had incredible luck as I managed to grab the very last transient tie down. Apparently they are ripping up the entire airport and remodeling it, so only a few spaces were available. Oh, and the 100LL was $4.40/gal. Ouch!

Flew home the next day, but only after waiting until 2pm when the fog finally lightened up and Palomar reported 4 mile visibility. It had been only 2 miles up to that point. We bolted to the airport and blasted off. Only a mile or so east of the airport and it was blue CAVU all the way back to Glendale.

Had yet another drip-drip leak with the left brake fittings. Drained the system, tweaked it, refilled it and now it is fixed until next time.

Finally decided to repack my Supertrapp muffler after meeting Pete Krok at the Brown Field fly in and hearing his horror story. His muffler clogged up and he was forced to land at a nearby airport to fix it.

As soon as we got back, I ordered the stainless steel wool repacking material. After pulling the muffler apart, I saw that even though the fiberglass material was still mostly intact, the baffle plates were partially clogged with chunks of it. I am SO glad I repacked it.

Did a quick test flight last weekend. OAT gauge read 106F on takeoff. Pulled the stick back to see what kind of performance I could get before temps rose too high, and had to very quickly do about a 45 degree bank turn to narrowly avoid hitting a huge hawk circling above the runway. Man, those things are big, and I would hate to hit one at 80+ knots. The really amazing thing though, was the rate of closing distance between us. That bird went from a small dot to filling the windscreen in about a second. It was more reflex than thought that made me turn the plane.

It was really miserably hot. Temp gauges were close to peaked out until I levelled off and reduced power, but no overtemp alarms. I am thinking of adding the cowl flap mod that people seem to be having good results with to bring up the margin of safety a bit. On the other hand, who the hell wants to fly around in a glass bubble in full sunlight when it is 106F outside? You don’t have to be crazy, but trust me, it does help.

09/25/2005: Got O2?

I wrote up a page describing a possible problem related to the oxygen sensor in the exhaust system.

10/15/2005: Double bust.

Haven’t done much flying lately, but now that the weather is calming down, we should have more opportunity to fly out.

Went down to the Copperstate on 10/8 (Saturday) and spent the day chewing on dust. Morning wasn’t so bad, but when the wind kicked up, Casa Grande airport became The Dustbowl. A stiff 15-20 knot wind was blowing by mid afternoon that never seemed to stop. The airshow was standard fare, so we bailed out around 2:30 with dust in our eyes.

We did see a couple of familiar faces, and did a little shopping. But attendance certainly seemed to be a fraction of what it has been in prior
years.

Was looking forward to LOE5 this year as one of our major fly out trips. Unfortunately, weather in the El Paso area was T-storms, hail, lightning and rain Saturday morning, and more rain predicted through Sunday. Risk assessment said “No-Go”.

Ahh well. We did fly to Sedona again today (10/15); landed and had breakfast at the restaurant. Always a nice trip to visit the Red Rocks.

01/21/2006: Cool time in Coolidge.

Amazing how two or three months can just fly by. We have added about 20 hours to the Hobbs since October flying around on a bunch of local trips. The first Saturday of the month had us in Coolidge (P08) for the Lions Club sponsored breakfast. We had a really great time – a whole bunch of folks flew in for the event. Unfortunately, I think we lost all of the pictures due to a camera versus computer snafu.

Last week, we tried to get to Payson for lunch. It was probably not the best day in the world to go fly as the winds were a steady 15-20 knots. It was also pretty bumpy north of the valley in the hills near Bartlett Lake, where we turned around and headed back. It was cool to see 135 KIAS on the Dynon, and 165 Kts ground speed on the GPS though. Flew the final into Goodyear at 110 KIAS and no flaps with winds 240 @ 22. That was fun. It is a relatively rare treat to get to practice a serious crosswind landing.

Unfortunately, I have been fighting what is now turning out to be a chronic inner ear infection. It has had me grounded a couple of weekends already – including this one. So, time to do some computer maintenance and web site updates. Also need to start thinking about the upgrades I will be making during my annual condition inspection coming up at the end of March. Wow! Has a year passed by already?

04/01/2006: Down for annual condition inspection.

Well, the subject line pretty much says it all. I am in the process of tearing things apart to do my first condition inspection.

Aside from the usual stuff, I am planning on a few “minor” upgrades.

The Dynon D10 EFIS is coming out and being sent in for upgrade to a D10A model. At the same time, I will be ordering the remote compass, OAT and AOA pitot.

The Grand Rapids EIS is also coming out for software upgrade, and also to have the “special” fuel flow option added. This will eliminate the FlowScan sensors and use the injector pulse length instead.

Looks like I will be down for most of the month. But, when everything is done, we will be ready for Osh this year!! If anyone else is flying there from Arizona, drop me a line. There is talk of planning a group flight out there, and maybe having a bunch of -9s meeting up somewhere and doing a mass arrival.

05/21/2006: Done. Finally.

Can’t believe it took me six weeks. And I still didn’t get everything done that I wanted to.

On top of the usual condition inspection stuff, such as oil change, remove all the covers for inspection, lube the bearings, etc., a few upgrades were put in.

The Dynon has been upgraded to a D10A with remote compass and OAT. The EIS was traded in for an EIS4000. A couple of new probes were added for fuel temperature and coolant pressure. Fuel flow is now calculated from injector pulses, rather than from the FlowScan sensors.

I did order the AOA pitot for the Dynon, however I have not yet installed it. Nor did I move the fuel pumps off the firewall. Nor did I do the fuel tank SB (fittings are Prosealed anyway).

All in all, a huge hassle, and I missed some great flying weather. We are now officially into the “Hot” season. A brief test flight this weekend had OAT tipping 105F. Very unpleasant to be out in the sun.

As part of the upgrades, I did manage to bring out the RS-232 connections from the Dynon and the EIS. I recorded data from both instruments on the test flight on my Linux based laptop. I’m hoping for a few long test flights to gather some data and really sort out my peak performance numbers.

Hobbs meter: 87.0 and counting

2009/12/24: Christmas Eve Joyride

It has been a few years since updating this section, so I decided to take a joyride and do a 4-way GPS run. I have lots of data files collected from Gen3 flights, but I am just too lazy to collate them into a table, so here is a single data point for reference.

Four Way GPS Test, 2009/12/24
Pressure ALT MAP (in Hg) FuelFlow (gal/hr) Prop RPM OAT (deg F) GS, KTS GS, MPH
8,000 23.1 10.1 2,700 47.0 155.5 178.8

In addition, I noted that the oil temperature was 198F, coolant was 186F, and gearbox was 172F for the entire run.

So there it is. Good, bad or ugly is your opinion. Frankly, I find it hard to be disappointed – this is less than 10 MPH shy of the official performance numbers advertised by Van’s, with no overt effort to “clean up” the airframe.

Hobbs meter: 307.6 and counting.