N3XH Phase 1 Flight Testing

[TLyon]

My 2c from flying the RV around is that a little portable setup is nice. Even in the 10-12k range the wife and I both feel better and less fatigued with a little oxygen after a couple hours up there. And sometimes a couple 1000’ extra can get you significantly smoother air. Not as much fun as being down low but nice to have options.

[rodsmith]

Completed another test this morning, one that is not in the test book. I wanted to determine the service ceiling for my airplane. I borrowed an oxygen set up for the test and was able to climb to 17,200, could have probably made it to 17,500 but the climb rate got real slow there. If I understand standard temp calculations, the temp at that altitude (27F) was 30 deg F above standard. Cruising at 17,000, MP was 15.8, 2200 rpm, 53% power so about 159HP, indicated airspeed 98kt, true airspeed 130kt., fuel flow 8.8 gph. I also had a cheap pulse oximeter to play with. Resting O2 on the ground at 6500 98%. Started O2 at 14000' 94%. Took off the oxygen at 17000, O2 bottomed at 83% within a couple minutes. One of my goals was to determine if I should get an O2 setup. I'm thinking not when I can cross the rockies at 12000'. Would be rare to need to go higher, and I definetly won't be flying over the mountains at night. I need to consider passengers though. My wife got a little light headed while 4-wheeling last week, at 12'800 on Engineer pass.

[rodsmith]

The extra time I spent insuring the rings were seated paid off. I was going to settle for 8 hrs/quart before talking to my tech counselor. Took several more hours and lots of fuel to get there before completing the testing. Finally had to add a quart at 21 hrs after my change to Phillips Victory. Determined that the correct starting oil level for my engine is 9 quarts. I started at 10 and it was down to 9 in 1 1/2 hours, another 21 hours to 8 quarts. My Maule would quickly dispose of any oil above 8 quarts. The O-540J engines have a different sump design,

[svyolo]

I got my 40, but went for quantity over quality based on wx and limited daylight. Still need to do the heavy weight stuff. Next week. I may end up with similar hours.

A light airliner or a fighter is a rocketship. A heavy one, is a fully loaded truck. No different, but you have to be able to fly both. Or, a light or heavy BH.

[rodsmith]

Completed my Phase 1 testing today at 44.9 hours logged. The extra time spent insuring the rings seated was responsible for going over 40hrs before completing all the test cards. I could have signed out last Saturday at 40.5 hrs but I was committed to completing all the test cards. I spent 22 hours completing the test cards. Overall the testing went very well. The eye opener for me was how different it flies at light weight versus heavy. It was only the last few hours that I flew it over about 2050 lbs. Approaching at 2300-2450 lbs at the same 60k, the cowling blocks most of the view of the runway.. It's almost like I have to learn how to land it all over again. So a few numbers. I determined Vy to be 65k Vx 55k. Rate of climb at Vy at 2344 lbs starting at 7000' (8800da), 1025 fpm. Vg, best glide speed 75k, 9:1 glide ratio. Minimum sink, 700 fpm at 60k. Huge difference in glide when the prop control is pulled all the way out at idle. You can feel the acceleration. I still have work to do with the AP. I was encouraged that it did a pretty good job on a very rough flight of keeping the wings level and altitude within 150' ( was penetrating 800 fpm thermals). The yaw damper did a great job of keeping the ball nearly centered. Next up is installing the Stolspeed VGs, then I will be repeating a lot of these tests. Pictures of 360#s of sand for heavy weight testing, including my co-pilot, Bagman Bob. The next flight I added a 7th bag for a take off weight of 2585, 20.2 CG. Handled fine, except not happy with the view on approach.

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[svyolo]

Stalls above 1g can be quite exciting. The more g's, the more "fun". I doubt anyone in a BH will stall at a high enough speed/G to make a difference. I did mine at about 65 knots IAS - no issue.

[jaredyates]

That matches my experience at forward cg. It will get more exciting as you move aft.

[rodsmith]

No better way to start the day than an early morning flight. My first flight in 4 weeks. I had the plane down for about a week for an oil change and to fix some squawks. The day I put it back together to fly the next morning I had a stupid accident causing a left shoulder injury. By the next morning I was in a lot of pain, no way was I going to fly for awhile. Couldn't raise my arm to level or apply any force with it. Took two weeks to get an x-ray and a cortisone shot in the shoulder which totally relieved the pain finally, nice to sleep again. Today I did accelerated stalls, test card 16. You are supposed to do them at a light forward weight and at a light aft weight, today was light forward weight. The tests were very inconclusive. You are supposed to roll into a stable 30 deg bank each direction, idle throttle and let it stall. Unlike level stalls I could not get it to break. Around 45 knots it would develop a big descent rate and tend to tighten the turn. This was true for no flaps, flaps 2 and full flaps, both directions. So apparently it stalls mid 40s without a break. AOA was indicating it was stalled also. Curious what others have experienced if they have done this test. By the time I landed I was at 11" CG, my most forward so far, I like the way it lands with forward CG. I'm at 33 hours now. I think I can finish the tests in a few more hours. Break in is officially over now that I have changed to a multiviscosity oil with the anti-scuff compound.

[gregc]

There is such a thing as too little oil consumption. It's a balance between oil use and cylinder wear.

[rodsmith]

Normal oil consumption on a 6 cylinder engine is a quart in 4hrs to a quart in 12 hours so I think you are fine.

I am probably setting my standards too high. Lowell's award winning homebuilt has an engine nearly identical to mine. He doesn't need to add oil between oil changes at 30 hours, and he had tougher conditions for breakin, doing it in July.

[gregc]

Normal oil consumption on a 6 cylinder engine is a quart in 4hrs to a quart in 12 hours so I think you are fine.

[svyolo]

I thing I am about a quart every 8-10, with no leaking, and I have a air/oil seperator.

I got my TW rating in a 65 hp Champ a few months before my first flight. I was a bit worried about the "high power" part of the TW equation on my 540 BH. Turns out the BH rudder is also "high power". I really didn't really notice a difference in that regard. Obviously the climb is a lot better.

[rodsmith]

I now have 28 hours on the plane. On my post on 2-18 I had reported I was losing a quart of oil in 10 hours. Turned out it was somewhat worse than that. After a detailed discussion with the most knowledgeable engine guy I know, I decided to work more on seating the rings. Lowell is one of our chapter tech counselors, was an engineer at Pratt and Whitney, after retiring there he moved to Colorado and spent 5 years re building Lycoming engines at Western Skyways in Montrose. He had stories about how engines that had failed to break in had been saved by very hard running for a period of time. He suggested long flights at as high a power setting as temperatures would allow, no additional landings or flight at low power settings. So that is all I have been doing the last 8 hours. A 2 hour flight, and two 3 hour flights. I think it worked. My last 5 hours of flying, I have seen no decrease in oil level. Although I have a 50nm radius test area, the amount of low elevation area is limited, and by low elevation I am talking 5-6 thousand feet. To get the most MP I found the best area to fly was the Colorado River valley between Grand Junction and Rifle. I have spent a lot of time flying back and forth in the valley at 6000', 500' agl. For about a 30 mile stretch there is a road that runs next to I-70, low traffic, no wires, seems like a great emergency landing option. A couple flights I saw 25" of MP pressure. I will take one more high power 2 hour flight, then change oil to Phillips Victory, then I can get on with flight testing. It's interesting how many close bird encounters I am having. Hawks, Eagles, Ravens, a lone goose. Today was the first time I had to take evasive action. Had a flock of 50 or so Sand Hill Cranes approaching at my altitude, made a 45 deg turn to avoid them. The more I fly this plane the more impressed I am with it. It is such a docile tail dragger. Actually should make a good trainer for a new pilot or pilot new to tail draggers, with an instructor skilled in teaching management of high power engines.

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[Nev]

I'd like to start a new thread on this topic. I expect I'm about to learn something here !

[Nev]

Very interesting Kev.