Dave’s RV-7A Building Log

Picked the worst week to start a new job. Five sunny days in a row is pretty unusual in Seattle. On top of that it’s only May. It was killing me to see the great weather pass by without flying. Luckily, the new job at Dynon is great. Way too tired to try flying after work, though.

Today the weather mostly cooperated. I went up for 1.4 hours in the morning. South of the Seatac class B, I was able to get up high enough to find some stable air. Before taking off, I squeezed the right aileron a little bit with the hand seamer. To this point, I’ve only squeezed it by hand. That certainly helped. With the left tank about 6 gallons lower, and the trim all the way to the right, I can now fly hands off at cruise. At slower speeds, it takes even less trim. Using the distance of my body and the fuel tank from the centerline of the plane, I figure it takes about 6 gallons of extra fuel on the right side to counteract my bulk flying solo.

So with the plane trimmed out and air stable, I was finally able to do the stability tests. I thought they were going to be difficult, but they’re actually very easy. The plane has positive static and dynamic longitudinal stability. The dynamic was pretty quick to settle when pushing the stick. Pull the stick took about 2-3 oscillations to settle. The plane also has lateral/directional control stability stability. The final test was for spiral stability. I’m not sure I’m doing the test quite right. You basically put the plane in a 15-20 degree bank and see if it recovers on its own. The problem is that a bank requires back pressure on the stick. When I let go, the plane immediately dives. I tried trimming the plane for slight back pressure before banking, and that helped. Still, it has neutral or maybe slightly positive spiral stability. From what I’ve heard, this is normal for RVs.

Second flight of the day was mostly just a fun flight. I did some slow flight, but mainly did a big loop around my test area. I went up to Arlington, over to Quilcene on Hood Canal, down past Bremerton National to Olympia, over to Enumclaw and back. In a car, that trip would take all day, mainly because of the ferries. In an RV-7A, it takes about an hour and a half. Very fun trip. Now up to about 23.5 on the hobbs. 40 hours is starting to feel like forever.

And just to prove I flew by Olympia, here’s a picture. The state capitol building is dead center and KOLM is at the top of the picture.

The weather wasn’t so great Friday, so I spent the entire day on the leg fairings. I got both assembled and fitted great, but didn’t do the alignment yet.

Saturday the weather was flyable, so I took the fairings back off and headed up. There was a thin scattered cloud layer at about 5000′, so I got above that and flew around. I did some more airspeed indicator tests at various speeds doing a simple back and forth with the direction of the wind. The indicator is within 3-4% of actual. Not bad. I’ll do some more accurate testing once I get a better day for it. I continued flying down around Olympia and then back.

Coolest part of the flight was the approach to Renton. A Cessna called in from the north end of the airspace (East Channel Bridge) and then I called in from the SE (Lake Youngs). Initially the controller told me to enter the downwind for 15. He then called right back and said if I keep my speed up I could have 33 with a 4 knot tailwind. Oh sure, I can keep my speed up. I’m getting more comfortable with what the plane can do, so I kept the speed around 130 knots until within 2 miles. I pulled the power back until flap speed and then dropped all the flaps. Once the plane was at 75 knots, I let it drop like a rock to the runway. Leveled off, touched down, off the runway before I ever saw the Cessna landing opposite direction straight in. Sweet.

Second flight of the day was similar where the controller gave me a straight in clearance to land right after a Cessna and taken off for a touch and go. I got to the runway and landed before the Cessna turned final. It’s a blast being able to scream past the spam cans.

In between flights I grabbed some lunch and decided to look further into the still heavy left wing. I took the wing tips off and aligned the aileron trailing edges with the tooling holes. I messed around with the ailerons for a while before I remembered that the elevator position affects the alignment as well. I then moved onto the flaps and aligned them with the ailerons. Sure enough, on the heavy side the flap was high. On the other side the flap was low. I fixed those two issues, but now the flap doesn’t line up the same on the fuselage. Strange. I’m sure the wing incidence is right, but I’ll check that as well. On the second flight, the heavy wing issue was better but still not completely fixed. I was going to do some stability tests, but I can’t completely trim the plane to fly hands off. I think I need to tighten the aileron trim springs as well. And I’ll try squeezing the aileron trailing edge on the light wing some more.

Just over 20 hours now total and everything is working great! Halfway through the test period. Now it’s time to concentrate on the wheel and leg fairings.

Today was a strange weather day. It was clear right over Renton, but looked to be cloudy all around. I couldn’t believe that Renton was the only sunny spot in the area so I went up in the RV. Clouds were at about 3,000′ and Renton was the only sunny spot. The clouds towered up quite high in places and were fairly solid so I didn’t want to try getting on top. I flew up the Snoqualmie River valley and back and headed in. Only 0.9 today.

I finished up the wing jacks and started working on the leg fairings. I used the template to cut them to size and found out I had to re-work the brake lines quite a bit to get the fairings to fit over them at the wheels. I started the loop in the line too high up on the leg. I eventually got them both fitting pretty well. That’s as far as I got with them today.

I thought yesterday was going to be a cruddy weather day, but it ended up being OK. I flew up to Arlington and had lunch. My first time landing the RV somewhere other than Renton. I put on 2 more hours getting up there and back plus lots of horsing around.

Today the weather was not so cooperative. The sun was out in full force for brief periods, but the storms kept rolling in one after another.

I worked on building some wing jacks as shown in a recent RVator. They’re very simple and cheap–bottle jacks on top of a stack of 2×4’s and 2×6’s. I made the stack 16″ wide, so I could get 3 layers out of each 8 footer. I ground some bolts to a dull point to use in the wing tie downs as jack points. Ran out of nails, but I almost got them finished.

I also made some of the light and cheap wheel chocks out of PVC piping. Could have used those yesterday at Arlington.

Also painted the spinner the standard gray primer for now.

I started looking over the instructions and plans for the leg and wheel fairings, but soon got very sleepy. I think all the flying over the last several days caught up with me. I ended up taking a nap with the dog in the back of the car.

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.