[ The Frye RV-7 Project ] Sunday, August 25, 2019  
 

 

Flight Testing


 
This section is for documenting the flight testing of N4932L. I have 40 hours to fly off, and a fairly detailed flight test plan to execute. The trials and tribulations of flight testing will be documented here.


First Flight!
Today the weather dawned rather less than ideal. Last night we had some kick-ass thunderstorms roll through, with some isolated flooding. Today we had low mist which lifted into low scud. The target time for first flight was 10am, but that slid by with still a low overcast at about 900 feet. It slowly broke up, and by about 11:30 it was flyable.

At the last minute Mark Glaser happend to show up, and without having any real time to talk he elected to fly chase. I'm glad he did, as his comments were very helpful. For instance, he reminded me that I needed to throttle up to seat the rings ... because at the time I was showing about 14 inches of manifold pressure. I bumped it up to 24 inches, and it was like a hand shoving me in the back.

Liftoff was straight-forward, with a bit of prop surging as it worked out air in the line (I believe). It settled out while I was on the ground and I elected to lift on off. From there it flew great until at some point I started getting a heavy left wing and some friction in the controls. I originally thought it was the trim out of whack, so didn't think much about it and just held controls against it. I was wrong, and as it turns out I eventually realized (after I was on the ground again) that the autopilot had kicked in and what I was feeling was me fighting the AP servos.

No big deal ... I could overpower them easily enough and keep control of the plane. But next time that happens I'll know the remedy is simple enough. Just reach up and punch the AP off. Doh.

Other than that, the plane few great. It climbed like the proverbial homesick angel. In no time I was fliring with 5K feet. It flew -fabulously- well, and I can't hardly believe I built it.

I had insisited on my family being there, so Chris, Katheine, Marie, and Theresa were all there. Not only that, our dog Skye was there too. Both Wally and George ended up being there, which was great. Along in the mix were Alice Ann Reu, Matt Waugh, James Garlick, and (as mentioned above) Mark Glazer.

It was a short flight ... 0.6, and very basic. I mainly got a sense for the flight controls, did one small session of slow flight to see where the IAS was when it stalled (right at 51 knots), and then back in to land. As I landed I was fighting the AP (I found out after the fact) and it was a horrible landing. The controls were stiff from fighting the servo clutches and so my handling was choppy. But I got it down, with a burst of power to control a bounce, and everything was ok. Moments after that I realized the AP was the blame .. and I wanted to go do the landing all over again, but knew I had to taxi on in.

Pulling the cowl (after Champagine) the only squawk was noticing that the engine baffle screws were backing out. I'll deal with that tomorrow. Other than that, it was nice and tight under the cowl. A real winner. The picture included here has the whole "First Flight Team", which is my family (minus Chris, who hatest having his picture taken but wouldn't have missed the event for anything).

After notifying Van's of the first flight the RV Hobbs Meter clocked over to the following value :

So, it flew. I'll be damned, but it flew. And flew well, to boot!
Logged : 0.6 hours

Relocate to KSOP
I've been working against a deadline, one that I swore I wouldn't let rush me. That deadline was the closure of the runway at KTTA for 50 days for reconstruction. As of September 4, 2013, at 12:01AM the runway is to be closed. Construction equipment is already being staged at the airport and workers are starting to swarm. It is either get out, or get stuck. I decided to get out.

The gating factor was how well the first test flight went, and it did go well enough that I felt I could do the 15 minute hop down to KSOP. We had to wait for clouds to lift enough, but after a delay (and a huge downpour from a passing rain cell) it did. The flight down was quite uneventful, and I made a really pretty landing. After talking with about 3 different people, signing various papers, getting a key and keyfob issued, I got N4932L tucked into the back of a large hangar.

We then stumbled across a friend and all went to Pik-N-Pig for lunch. After that we ferried N2880G to Kimrey (after stopping at Burlington to wait for George to get down in Chapel Hill). It made for a very long day, not without some sadness. Being chased out of KTTA, the airport that is "home", was a bit depressing. But this too will pass and there'll be the happier opportunity for a homecoming in a few months.

I did fill the right tank for the first time, and I think I have another fuel weep. Dang it. I also need to adjust my low pitch stop as I can turn over 2700RPM if I go full throttle and full forward on the prop control. The tank is going to be a bitch, but the prop should be easy to adjust. Time for a little wrench-turning, and a few more flights.

I think I'm just going to live with the weep (and avoid full tanks) for a bit. I'll only be doing hour-long flights for the forseeable future anyway, and might wait until I'm back at KTTA to wrestle with the tank.
Logged : 0.5 hours

Move Tools
Today with the help of the family I moved some of my tools down to the new hangar. I also took a table, chair, creeper, and a stool. My hangar-mate, a Citation Mustang was there since it was a weekend so I finally got a look at it. A pretty little jet, I must say.

That said, the back of the hangar where the RV lives is filthy. I will need to at least do a quick sweeping of the area just so my creeper will move without bogging down on the dirt-bunnies.

I also pulled the spinner to remind myself how the prop fine pitch adjustment worked. A nut to lock it in place, and the adjustment itself is made with an allen wrench. Good deal.

Post-Flight Check / Cleaning
I made it down after work (not easy, because KSOP is a long way to drive) to get a little done on the RV, and the hangar. I stopped by KTTA to get my big push broom, and one of the first things I did was sweep my area of the hangar. It is MUCH better now.

I also had a bit of oil to clean up. As per the engine specs I put in 8 quarts of oil, knowing some would blow out the breather. But this let me allow the engine to settle into whatever its natural oil level might be on its own ... with the penalty being a mess to clean up off of the belly. It seemed to want to settle to a solid 6 quarts which is exactly what I would have expected.

I pulled the cowl and gave the FWF area a -detailed- inspection. I had nothing loose, and everything seemed to be as it should be. I do have some darkening of the cowl where the exhaust pipes run, but no blistering yet. So this shows me -exactly- where I need to put heat reflective material which I'll order from Van's today.

I wanted to make an adjustment on the prop, but really need a deep 9/16ths socket to get the job done. I'll pick that up today or tomorrow too.

I'm not going to be able to go out to the airport after work much, as it is just too long a drive. I'll need to dedicate a weekend day and one (or maybe two) nights a week for going to KSOP. I sure hope they get the runway done at KTTA soon!!

Another Breakin Flight
After discussions with a few people about the prop adjustment, and after reviewing the downloaded data from the EFIS, I've decided to wait a bit before adjusting the prop. I now think that the prop may well be right where it belongs after a look at real data (as opposed to fragmentary impressions during a hurried flight).

Today I was out to make another test flight or two. After a careful preflight I took off for a flight intending to work a bit more through the engine break-in period. Before starting on working off flight test cards, I want to make sure the engine has had a chance to get broken in nicely.

I did have one bit of excitement today, which happened after landing. Once again I had oil on the plane, and this time I couldn't blame the breather. After de-cowling the engine the problem was quickly found. An oil return line from the #1 cylinder had worked loose. I had put a wrench on all the oil _hoses_, but overlooked these return lines assuming (without even thinking about it) that they would be tight. I only lost one and a half quarts, but it made a huge mess and made me want to kick myself.

I replaced the oil, used up a lot of shop rags getting clean again, and put a wrench on each and every AN nut, particularly the cylinder oil return lines. By the time I took care of that (had to drive back to TTA to bring down a case of oil) there was no time for a 2nd flight.

That said, I got a good break-in flight going from SOP, to TTA, to 5W8, to HBI, to RCZ, and then back to SOP. I thought my flight test area was pretty big ... until I flew a significant chunk of it in an RV. Good grief, it eats up ground fast. And this wasn't trying hard, and was done with no wheel pants or gear leg fairings.

I hope to get another flight in this week, if I can, but next weekend will be consumed with flying Theresa to the mountains (in the Citabria, of course). We'll see what I can get done, but having the RV at SOP does make it a bit harder to work out time to fly.
Logged : 1.4 hours

Yet Another Breakin Flight
Once again the distance from work/home to KSOP kept me from being able to get any flying done during the week. I almost made it down Thursday night but my son had hand surgery and I decided I wanted to spend time with him as he was recovering. I'm glad I did because his arm was totally useless until the next day, and uncomfortable even then.

I did make it down Sunday (with Saturday out due to winds I wasn't willing to deal with with only a few hours on the RV), and got in two flights. One short one to see if my oil issues had been resolved (they appear to be, though I still seem to be leaking a SMALL amount of oil from somewhere .. time will tell), and a second longer flight. Both were uneventful.

I do still have a heavy left wing, but can trim out the weight. I'll address that once I get back to TTA. Same thing for the tank weeps. My primary focus in these first few flights are to break in the engine and feel out the plane. So far that is going well, and I'm finding it easier with each flight to keep the CHTs in line. So far, so good. :)

One shock that happened last week was my plane got moved to another hangar. A concrete floor covering company finally caved in and agreed to re-cover some floors that had problems, and the E-2 hangar I was in was one of the affected units. I got moved to the Group 4 hangar (makes me think of the Group W bench, for those of you old enough to get that reference). The move was uneventful, aside from giving me a heart attack when I was informed after the fact. In their defense they tried to get in touch with me so I could do the move, but I was out of town and didn't get the message until it was all done.
Logged : 1.8 hours

Chasing Oil
After my last flight I had not pulled the cowl, simply because I ran out of time. This meant that when I went back out last weekend I had to pull it and check everything ... and once again I found oil. I really had thought I had the oil leak knocked, but found more oil than I was happy with after all. So I cleaned it up, buttoned it back up, and decided that rather than fly I'd call Malechuk and see how best to proceed. So no flying last weekend.

Today I carved time out from work to fly it over to Siler City and spent some time working with Jeff to track down the leak. As it turned out a few ground runs made it clear where the oil was coming from, where flights had not. In flight there was too much blowing around for me to be able to identify the source of the leak.

As it turned out, with the engine being new a few bolts along the spine of the case needed some additional tightening. Particularly the bolt to which the lift ring was mounted. With those snugged back up the leak appeared to be gone. We checked all the bolts on the case, as well as snugging up all the bolts on the sump.

When I got back to SOP, it was also time to move out of the Group 4 hangar and back into E-2. The floors are done, and I'm back in my original location. Hopefully, for only another 11 days, as that is when the TTA runway project SHOULD be completed. (Crossing fingers.)

When I was out at TTA this morning picking up a few items from my hangar I took a few pictures of the runway. They have a good distance to go. However, coming back from Siler City I did fly over TTA and saw seven dump trucks lined up feeding the paving machine. Hope springs eternal!
Logged : 1.2 hours

Odds and Ends
The clouds were low, and it was off-and-on rainy, so today was a good day for doing work on the RV and not flying. I had a laundry list of things to work on and made good progress.

First thing to do was to pull the cowl from the last flight and see if the oil leak had been conquered. As it turns out, there is STILL a VERY SLIGHT leak. I tightened the bolts just another tad, and we'll see if that stops it. But it is down to a point where it isn't causing a big mess when I fly ... which is moving us in the right direction.

While I had the cowl off I replaced the old rubber boots which were on the purge valve cable with new blue-colored boots. I bought these cables a number of years ago, and the rubber was already deteroriating. Replacing them now while it was handy to do so made sense to me.

I went back and did some reading about how to address the heavy wing, and started with the most basic verifications. The first thing to check was the flap rigging. I did find the right flap slightly lower than the left, so first work to rig them identically. Using the flaps as a reference I then re-rigged the ailerons. I can say this in a few short sentences, but it really took quite a while to get the job done.

I had also decided that rather than the ON-OFF-(ON) switch I had for the flaps I needed an (ON)-OFF-(ON) instead. This is because if I left the up-flap switch engaged (i.e. the toggle locked up) the next time I powered up the VP-X it would see a flap fault. This was the easiest piece of work I did all day. It took all of 5 miutes and worked like a champ.

I didn't get all the way through my odds-and-ends work list. I still want to reprogram the APRS transmitter, and want to re-rig the elevagor to move the stick forward a bit. I'll pick another rainy night this week to go get that done.

I also stopped at TTA on the way to SOP, and on the way back. In both cases I checked on the runway progress. Today they clearly got one more "stripe" paved, and it appears to me that they only have one left. I have been told they are going to put down one more top-layer (of higher grade asphalt to make it nice and smooth) and they clearly still need to pave the short taxiway segments that connect the runway with the main Alpha taxiway. Then temporary markings. Then we go home. I hope. :)

Homecoming!
The work on the runway was completed this last Thursday, so Friday Wally and I carved out some time and brought both the Citabria and the RV back home. It was a short flight, but had the happy ending of tucking the RV back into its home hangar.
Logged : 0.6 hours

Landing Practice
Today I just wanted to work on my landings. Right now they are not nearly as nice as I would like. I had very little time, and a lot of that was consumed with talking to people at the airport. Even so, I got in 0.5 of flight time and about 5 landings. They are getting better. Now that the engine break-in is well on its way I can afford to do some T&Gs, but mainly need to get moving faster on the formal test flight program.
Logged : 0.5 hours

Belated Updates
I've been remiss in tendering updates. Since I'm no longer logging actually build activities the discipline to update the log has waned a bit. Oh well.

I've done a lot, even if I've not gotten in nearly the number of hours I'd like at this point. I'm only at the 10 hour mark due to having to work on the tanks, rotten weather when I was free to fly, and travel. I'm about to head to California again next week, and the forecast for home is .. wouldn't ya know it .. for a week of absolutely perfect weather. *sigh*

However, I have gotten some flights in, as well as having worked on a number of large and small issues on the plane. I had three leaks in the right tank (zero in the left, so far, however). I had a weeping rivet on the bottom, so slight that there wsa never a drop on the floor but just a blue ring around a rivet. I had a -leaking- rivet high on a rib, just under the leading edge. And, finally, the nut on the fitting which exits the tank came loose! I tightened the nut and that fixed that problem. The leaking rivet was so bad I drilled it out, used a closed-end blind rivet, and a lot of proseal to fix it. So far, so good. The weeping rivet I fixed with the green Loctite fix, not even pulling any vacuum to draw the Loctite into the leak. It wicked up with no help at all and has stopped that weep quite nicely. We'll see how that holds.

I also reprogrammed my APRS transmitter to change what was being reported, and some of the parameters which drive the reporting. In doing so I had to remove the right wingtip ... and those POS ClickBond nutplates started to pop off as I went to put the tip back on. I got so mad that I snagged a #6 screw in a vice-grip and intentionally popped each and every one of them off. That was a lot of money down the drain, not to mention a lot of time to install regular nutplates along with the requisite AL backing strip. I'll do the same to the left wingtip eventually. Frustrating!

I'm still watching my CHTs carefully, and still find it easy to get up around 400+ degrees if I'm not careful. That may be a bit of a work in progress for some time to come. I'll try and make more regular updates but don't promise to succeed. :)

More Belated Updates
That promise to try and make more regular updates I made in the previous entry? Remember that? Didn't work out. :) Life has been too hectic, and I've not felt like I had all that much to report. Flight testing has been progressing slowly due to work and weather, but it has been progressing. That said, it is time for an update.

Yesterday was a real (to me) milestone in my flight testing. It was finally tine to get into acro. Spins had to come first, only because I had to know how it would recover if I botched a particular maneuver. I started very VERY slowly ... doing stalls with the ball halfway out (both left and right) to see how the wings dropped, then having the ball all the way out (again, both left and right). I did a number of these to satisfy myself that it was consistent and controllable, and it was.

So I then did quick spin entries-and-recoveries where I didn't let it get fully developed. The spin entry is much more dramatic than in the Citabria, but it recovered just fine. My goal was to work up to a 2-turn spin because that would allow it to fully develop which would give me confidence in the recovery. It spins FAST, so my 2-turn spins ended up actually being 2.5-turn spins when it was all said and done.

I had been willing to have that flight end with spins, if after they were done I was feeling tapped out ... but they really did go well, so I continued on. I did my first roll, and it was -ugly-. I was still carrying over some technique from the Citabria, and my movements were too "large" for the RV. So I dialed in back and the 2nd one was better, but still not pretty. So I dialed back my movements a bit more, and .. oh my god .. does it roll pretty.

Do it right (mainly, don't ham-fist it and let it do what it wants to naturally do) and the world just rotates gracefully in front of your eyes. I was up at 8000 feet over 421 near Siler City so I pointed at the airport and rolled. I could watch the airport go around right on point in front of my nose. It was rolling great to the left, so I tried a roll to the right. Same outcome. It was astounding. By the time I did about my 4th roll I was just laughing out loud. By the time it was all said and done I had probably done a dozen ... and in one case did two back-to-back. Wow.

I started at what for the RV was a fairly low speed ... entering the roll at about 120k. Since I was full throttle doing the rolls it actually accelerated through them and by the time I was done rolling left then right then left then right again .. I looked down and it was doing 160k. I _had_ checked with a friend who is a very experienced aerobatics pilot regarding entry speeds (he has owned an RV in the past) and he said it just didn't much matter. That it almost didn't matter for the loops, though you obviously need some speed to have enough energy to get over the top.

Since -that- went so well I decided to try a loop. I have to say before the first instance of each of these maneuvers there was a small bit of anxiety. I think it is kind of funny to have that anxiety hit again after all those rolls, but before the first loop .. I'd rolled, and rolled, and rolled .. but when it came to do that first loop, the anxiety came back. I knew it was because this plane had never done a loop before, so I had no idea how it would behave. It is the "good kind of anxiety" in the sense that it wasn't paralyzing, but it did cause me to focus, think through exactly what I was going to do before I did it, and plan for what to do if something went wrong. If that distinction makes any sense.

Anyway, the loops .. of course .. were fine. No problems. In fact they became so comfortable that I finished with a couple of 3/4 loops with a roll off the backside (i.e. a sloppy half-cuban) to wrap up. I'm glad I didn't accidentally key the mic because I did a lot of laughing through this whole process.

It was very bumpy down low, but up above about 3000 feet it was nice and smooth yesterday. I wanted elbowroom so did all this up at 8000 feet, and it was glassy smooth up there. Since the air was so nice I decided to do the one last really scary thing on my list ... flirt with Vne. I had already been to 180 knots, so it was "just" another 20 knots .. and I put that "just" in quotes because flutter can appear suddenly with a seemingly inconsequential increase in speed. So 20 knots is a big leap.

I had to dive for that kind of speed, and eventually saw 200 knots on the ASI and nothing fluttered. Wanting to explore the margin I actually worked up to 205 knots, so I now _know_ without a doubt that the 200 knot Vne is safe for my instance of this design.

This was a simple little 0.9 hour flight, but it felt like a HUGE step. This was almost as big a day as my first flight. One of the reasons I picked this design was because it was aerobatic, so being able to do acro was part of the equation LONG before I had ever started doing acro myself. It felt like the culmination of a 12.5 year delayed gratification exercise.

The Citabria taught me basic acro and forced me to pay attention to the aerodynamics and what was happening throughout the maneuver. If you don't understand and pay attention you will no complete a maneuver successfully in the Citabria. The RV is going to ruin all the hard "work" done by the Citabria because it is just too easy. I know it isn't as "point and shoot" as the unlimited acro machines out there, but it is awfully nimble.

I'm up to 29 hours now, so only 11 left to go before I can get out of the box it is in right now. Slowly but surely I'm getting there.

Out of Phase 1
Today I clocked up to 40.21 hours on the hobbs meter, and I've flown all my flight tests, and can declare officially that N4932L "has no hazardous operating characteristics or design features, and is safe for operation". That is to say, it is out of phase 1 and is free to roam (and to fly at night, and to carry passengers). Let phase 2 begin!

This means it is also the end of the "FlightTest" section of my blog. :)

 

 


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