Dave’s RV-7A Building Log

With this week off from work, I have nothing to do but fly and work on the plane. Weather was perfect this morning, so I went with flying. I did a 1.5 hour morning flight, returned for lunch, and went up again for 1.6 in the afternoon.

The air was steady and the winds light, so I did an airspeed calibration run. I looked up the winds aloft before take off and verified the direction by doing a 2 minute turn at a steady altitude while watching the ground speed on the GPS. It took a couple of turns before I could hold the altitude and bank angle steady. I thought an electronic VSI wouldn’t have the lag factor of an analog unit, but it does. Once I figured that out and concentrated on the gyro horizon instead things went much better.

I chose 020 and 200 for the speed runs. I cheated and used the autopilot to hold a steady course and altitude. The AF-3400 calculated the TAS as 144 knots in one direction and 145 knots in the other. The GPS grounds speeds were 151 and 147. Averaging produces 149 for an error of 3%. Not bad. I should have repeated the test at a few different speeds, but didn’t think of it.

The AF-3400 is supposed to be able to calculate HP or percent power based on a few numbers. I had most of them from previous flights, but needed fuel flow and EGT at 75% power leaned for maximum power. I did that run and recorded the values, 12.3 gph and 1250°F.

To burn off some more time I flew west over to the peninsula. I’m getting tired of running up and down the corridor east of Seattle. I did a big loop over to Port Townsend, Bremerton, Tacoma, and back up to Renton.

On the second flight, I did some more stalls and this time recorded the airspeeds. Power off, no flaps was 48 knots. Power off, half flaps was 47 knots. Power off, full flaps was 47 knots. The test card then called for some power on stalls. With the power/weight ration of the RV, these can get pretty crazy. I tried 17″/2300 RPM and got 46 knots. I did another stall at 23″/2300 RPM at about 44 knots. I didn’t take it any further. At 23/2300, the nose is really pointed at the sky. Plus, I didn’t want to cook the engine. These numbers are lower than the Vans stats, but I did all of these at solo weight.

I flew back south again toward a little town called Carbonado. It’s tucked back in the woods toward Mt. Rainier. After that I headed north and in for a landing via Lake Sammamish.

3.1 hours on the day and everything is working great.

Ended up burning up most of the day waiting around for a delivery. Didn’t get down to the airport until 4:30pm, but I made the most of it. I flew around for 1.4 hours. Here’s my gratuitous shot of the mountains.

Here’s me bombing around at 8,000′.

And here’s a shot of Snoqualmie Falls that I shot right before heading in.

I didn’t have time to really plan out the flight, so I just messed around. I found the highest altitude where I could still get 24″ of manifold pressure. That ended up being 6,000′. I turned on the autopilot and waited for it to stabilize. The EFIS read 147 knots true airspeed. Not bad. I don’t even know if the airspeed is reading correctly yet. Supposedly I’ll pick up another 15-20 knots with the wheel pants and fairings, so this is looking good.

I flew up to 8,000′ and did some more fully developed stalls. I waited for the plane to actually break both with flaps up and down. I turned on the AOA indicator and it seems to be pretty well calibrated. It was giving me a warning about 5-10 knots before stall.

Cylinder head temps seemed to be lower as well at 360°F, but that might have been due to the outside air temp of around 20. After messing around at 8,000′ for a while, I swooped down into the Snoqualmie River Valley, flying 1500 AGL or so (it’s all fields) up to the falls. That was a kick. I’m lovin’ this plane.

Weather cooperated, so I went up for two flights this afternoon, 1.0 and 1.5. The total is now just over 10 hours.

My goal on the first flight was to get up to higher altitude–convenient since the lower altitudes were bumpy. A bunch of little cumulous clouds were forming at 5,500′. Unfortunately, I had to go quite a ways to get out from underneath the Sea-Tac class B airspace. Once I did, I went up to 8000′ pressure altitude. Much smoother. I did some straight and level runs with the throttle wide open, but I don’t think I was getting the peak performance. The manifold pressure was 22″ or so. Max true airspeed (I haven’t verified the airspeeds in flight yet) was about 145 knots. Air temps at that altitude were below freezing. Luckily, the heater works really well as I had shorts and sandles on. Hey, it’s 65 in Seattle. That’s shorts weather. Maybe not so good for flying, though.

After an hour, I had to come back in for fuel as I didn’t take off with full tanks. After stopping at the fuel pump, I had a little trouble starting up again. I think it was some fuel vapor problems. Back at the hangar, I took the cowl off. No oil leak still. Yeah! I did find the prop cable is now rubbing on one of the oil cooler hoses. I had to re-orient the fitting in the oil cooler to keep it from hitting the engine mount. Now it rubs. I’ll have to put some spiral wrap around it or something.

For the second flight, I cherry-picked some tests to do from the first 4 test flight cards. It was mostly slow flight with turns with and without flaps. At first I had trouble maintaining speed and altitude, but eventually got better at it. The plane really handles great. I was getting close to stall speed once and felt the buffet. It’s a really obvious indicator of an impending stall.

I flew up to Arlington in the process of doing the tests. On the way back, I turned on the iPod and autopilot, kicked back, and just enjoyed the view. And what a view it was. A little hazy, but the mountains were spectacular from 6,000′.

I messed around with leaning the engine as well. The EGT peak detection function on the AFS is really quite nice. As you pull the mixture back, it finds the peak temp. Then as you make further adjustments, it tells you if you’re rich or lean of that peak. Quite cool.

I’ve got next week off between jobs, so I’m hoping I can burn off some more of the remaining 29.8 hours. My CHTs are still a bit high, but never go above 420°F. Still, I’d like to figure it out. I think air is leaking around the baffle seals.

During the process of changing the oil, I removed the oil cooler and took out the elbow fittings. I re-installed them with teflon paste this time instead of fuel lube and put 6 quarts of mineral oil back in the engine. I ran the engine for 10 minutes or so and checked for oil leaks. None.

The weather wasn’t looking so hot yesterday, but was good enough today. Ceilings were about 6000′ with a slightly blustery wind. I went up for an hour of burning up the skies at 24″/2400 RPM. I definitely went up another notch on the comfort scale today. I did a few stalls with and without flaps. They are very tame. I also did a few steep banks. The plane is just plain fun.

Racked up another 1.0 hour running down to Pierce County and a bit south of there. It’s amazing how quickly you get into the boonies down that way. I think just a few more hours of running at high power settings and I can finally get into the formal flight testing.

The landing wasn’t beautiful, but not bad for my first crosswind in the 7A. I still tend to over-control. The stick is very sensitive. Very small inputs are needed.

Took off the cowl and confirmed that the leak at the oil cooler is fixed!!

Arranged to have a guy drop by from Washington Avionics to do a transponder check. I learned there are two flavors of check, IFR and VFR. Since I’m just flying VFR for now, I figured that was good enough. He said the first check has to be IFR and then I can do VFR after that. Who knows, maybe I’ll be ready for IFR flying in two years.

His equipment was pretty old looking, but worked well. We tapped into the static line, tested the instruments, and then tested for leaks in both ends (foward and aft) of the static system. No leaks and the altimeter on the AF-3400 was within 10′ all the way up to 20k’. The guy joked that he’d stop by next time he needed his equipment calibrated. He also checked out the pitot system. It was dead on and no leaks. Good to go!! (Don’t ask me why I didn’t do the check sooner. I got some bad advice and misunderstood the requirements.)

With that done and the skies clear, it’s flying time. More engine breaking in at 24″/2400 RPM. I flew up to Arlington, back toward North Bend, and back into Renton. 1.1 hours on the Hobbs.

I snapped a bunch of pictures in the air. This is Lake Sammamish followed by a shot west toward Seattle along I-90.

This one is Mount Si in North Bend with the Cascades in the background.

I should have zoomed in on this next picture, because it was really very, very cool. The little green patch in the middle of the forest dead center is a jumping off spot for hand gliders on Tiger Mountain. There were about a dozen of them circling around. I stayed way up and over so I wouldn’t spook them. I’m sure an airplane is not a good sound when you’re flying one of those things.

Very fun flight.

When I got back, I de-cowled the plane and drained the oil. Time for an oil change and to fix the leak at the oil cooler. I’m tired of the oil dripping on the inside of the cowl.

Went down to the hangar to work on the plane a bit, but ended up going up for 1.0 on the Hobbs. I first re-installed the EFIS. I sent it back while I was in Hawaii. The AHARS needed a firmware upgrade. It’s easy to update the EFIS firmware with the flash card slot, but the AHARS requires special equipment.

I also finally put the covers over the center floor area and fuel pump. And put the Classic Aero carpet in place. It looks really sharp.

Final task was to check out the fuel pressure transducer. There’s some troubleshooting steps I followed that involved measuring the resistance at the sensor when applying different air pressures to it. That all checked out fine. I put it back together hoping it would just work, but the pressure is still reading high. Next I’ll try reading the fuel pressure while applying air pressure to the sensor.

With all of that done, I figured I deserved a little stick time. I put the cowl back on and pulled the plane out of the hangar. The weather was supposed to be cruddy today, but it ended up being fairly good. I had to dodge rain storms a little, but the flying was good.

I’m still breaking in the engine, so I went up to 4000′ and buzzed around at 24″/2400 RPM. While I was going up and down the Snoqualmie River Valley, I checked the ground speed on the GPS. Comparing that to the true airspeed (TAS) on the EFIS, it was reading about 10 knots high on the way up and a little less than 10 low on the way back. Looks like the airspeed is reading correct +/- 5 knots. I’ll check it out more precisely soon. I’m hoping the wheel pants and leg fairings add some serious speed. Right now cruising at 24/2400, I’m getting about 140 knots TAS. That’s nothing to sneeze at, but I’m hoping this puppy cruises around 170 knots at that power setting.

After that flight I had about 5.5 on the Hobbs and 3 on the tach. Not sure if the first oil change is supposed to be 5 Hobbs or tach, but I think I’ll just go ahead and do the oil change. Better safe than sorry.

Speaking of oil, I’m really not burning much oil. It went from 8 down to 7.5 in the first flight, burned 1/4 quart the next flight, and almost nothing since then. Can the engine really be breaking in that fast?? Let’s hope so. I’d like to get on with some of the more interesting flight testing.

One final note, I ordered a Halo headset from Quiet Technologies. Everyone on the RV forums raves about them, so I figured I’d give it a 30 day trial. So far I’m impressed. It’s much more comfortable than a headset and actually sounds better to me.

Last August we planned a trip to Maui. Seemed like a great idea at the time. We didn’t know it would be just a few weeks after the plane got airborne. Oh well. I still enjoyed myself despite missing the RV.

I’ve got a bunch of squawks to take care of this weekend and then I’ll be back up in the air testing out the plane.

In other big news, Dynon offered me a job as an embedded software engineer! I’ll be starting there in a few weeks!! I’m very excited to work on their avionics with the great folks I met there. I’m not sure what I’ll be doing with my AFS-based panel long term, but for now I don’t want to take the plane down to mess with the avionics. The AFS screens are working, and I want to fly the plane instead of working on it this summer!!

Went down to the hangar to pick up something after work. Ceilings were 5500′, wind straight down the runway at 5 knots. Hard to ignore that siren song.

The cylinder temp spread from the front to the back was still a bit high on the last flight, so I put a little more aluminum tape on the front of the front cylinders as a temporary test.

The idle seemed a bit high on the last flight, so I backed out the idle screw 1/4 turn. It seemed like the quadrant lever was hitting the bottom at that point, so I screwed in the clevis end one turn to shorten the cable. Re-secured everything, re-checked everything, cowl back on, pulled her out of the hangar.

I put another 0.9 on the Hobbs. I’m still breaking in the engine, so no serious flight testing yet. I flew at 24″/2400 RPM this time and the cylinder temps are all within 25°F of each other. Actually, they are all within 10°F except #1 which is still 25°F low. Maybe a tiny bit more tape on #1 and that will do it.

The flight went perfectly. Renton to Enumclaw to Monroe. That was half an hour. Back down the Snohomish River Valley, across Lake Sammamish and into the pattern. Slowed down much earlier this time and that was a good thing. Also figured out that last flight I forgot to put in the last 20° of flaps. That’s why it felt like I was going so fast and floating. This time I was just a tiny bit low on final (need to keep more power in–probably because I still don’t have wheel pants), but the landing was great.

The GNS-430 GPS is also working much better now. I figured out after the last flight that the cards weren’t pushed in all the way. It can now figure out when I’m coming in for a landing at an airport and doesn’t complain about terrain and obstructions. I also bumped up the sidetone volume to the top value of 63. It’s better, but still not as loud as the SL-40.

Awesome, awesome flight. I still get a little worried whenever the engine changes tone, but it’s usually just because I’m drifting up or down. The engine is running like a champ and the plane handles incredibly well. It’s so very cool to just go up for a flight on a whim instead of scheduling the rental 4 days in advance just to find out it’s down for maintenance.

When the sun came up this morning, it was obviously going to be a perfect flying day. I decided to fly in the morning rather than risk the weather later on.

I got down to the hangar, put the cowl back on, and got her ready to go. It was a very cold morning. The canopy started to fog up a little when I got inside.

Run-up went great this time. Tower indicated a 737 was going to do first flight in a few minutes, so I lined up for departure and took off. I forgot to turn on the transponder, but luckily I set up the feed from the GPS last night, so it automatically flipped on. Cool!!

I flew Southeast from Renton climbing up to 4500′ once I passed Lake Youngs. I kept the power at 25″/2500 rpm in order to facilitate breaking in the engine. I cruised south a ways to almost Enumclaw. At some point I said to myself, “Relax, everything’s working great.” I took a camera up and snapped a few shots: Mount Rainier, the Olympics with Seattle off to the right, and Tiger Mountain.

I turned north and went between Squawk and Tiger mountains. I tried out the autopilot for a while. Works great, although I don’t think it’s receiving the feed from the GPS yet. I probably have to fix a few settings.

My plan was to go up the Snohomish River valley, but it was completely covered in fog. I started heading toward North Bend, but it got a little bit rough with the turbulent wind off the mountain tops.

I dinked around a bit and then headed in over Lake Sammamish. I definitely like the SE approach to Renton better. Newcastle is fairly high up.

I still had too much energy on final. And it seemed like the idle was set too high. She eventually drifted down and I turned off by mid-field. It’s nice to have 5000′ to work with.

I also started working on graphing some of the output from the AFS engine monitor. Check it out here.

Weather was fairly decent all day. Lots of clouds, but sunbreaks as well. I ran down to the airport after work. Of course down there the weather wasn’t so good. A rainstorm was perched near the airport, but didn’t seem to be moving.

I cowled up the plane and taxied to the runup area. A few drops fell on the plane, but not enough to abort. During the runup, the RPM wasn’t dropping on the right ignition and dropped out completely on left. Not good. Back to the hangar.

I took the top cowl back off and this is what I found.

I’m not a huge fan of these connectors. The screws are so small that you can’t get a real screwdriver on them. I thought I had them torqued down enough, but I really tightened them this time. I also checked the right side. They didn’t seem as loose, but one wire definitely had slipped a little. I’ll check them again after the next flight.

After all of that messing around, the weather really hadn’t improved. Rain was threatening. And the temps were dropping. I figured the last thing I need to deal with is icing. Mission scrubbed for today.