New plane's first flights

It's always interesting when a plane you've spent months working on has it's first flight. No matter how much bench triming you do, you just never know what it's going to do that first time in the air.

My new one did pretty well overall. Had a horrible tilt to inboard on takeoff. Thought the thing was going to roll over. but a bit on trim on the adjustable tab and some tip weight (knew I forgot something) took care of most of that. A bit of tweak to the flap took care of the rest. The plane is, well, a bit different. 69" wing span at about 7 to 1 AR spread over about 720 square inches. 2/3 span (and small) flaps. Weight is a bit heavy at about 67oz. Very long tail moment with an airfoiled stab. Power is a Stalker .61RE with Smith/Werwage 3 chamber, large, Diamondback pipe. Bolly 12x4 3 blade is what I ended up with, though it went pretty well on the 12x4 3 blade Eather underchamber. The line tension is better with the Bolly. The 13x4 3 blade Bolly was a bit too much prop, I think. Tended to want to get loose in the overheads with this one. Don't know why. Running at a constant, rich 2 stroke at about 11,000 rpm. 5.4 second laps. I'm really starting to like this engine.

I flew at my least favorite but closest site. A school I lovingly call "The Washing Machine". 2 story gym on one side, line of 100 foot firs on the other with a nice 50 foot tall hill side to box in the area. Basically, you fly down in a hole. With the wind blowing, it's a real thrill. The wind may be at your back where you're standing, but blow 90 degrees around where the plane is at. Can be interesting, but the new plane didn't seem to much care. Bounced a bit in the turbulence, but ignored the wind. Line tension was good to too much pretty much everywhere. Probably need to move the leadout forward a bit. I'll get to that on the next outing. I was abit concerned that I only had about 15 degrees of elevator movement and wondered how well it would turn. Well, that isn't a problem. Probably has to do with a ridiculously long tail moment and good sized elevators. Doesn't take much. And shock of shocks, I've finally built a plane that tracks. Goes right where you point it and stays there till you tell it different. A nice change.

Well, I rambled enough. I like it a lot and now I don't have to rush my current project into the air. For those attending Roseburg for the Northwest Regionals, see you there.

Interesting post. Your loading is about 13.4 oz/ sq ft., which is a bit on the high side, but it sounds as if your plane flew quite well.

I'm going to try to keep this thread going with the question to all: what do you typically do on a first flight. The gamut ranges from straight and level the entire time, to a full pattern.

I usually don't fill the tank full, and maybe will do a loop or two, but that's basically it. I'm climbing and diving, and especially looking at the amount of wing tilt, hoping that there's not much to see. The next flight, I'll go inverted, and check tilt again.

First I hope to see you (Randy) in Roseburg. First flights ...a GREAT question. After running the engine in the plane both up-right and inverted and at LEAST four tank fulls before any lines go on the plane. First I pull test, Second I make up a patteren of level upright flight of , take off, level flight, climb to 45 degrees, back to level flight. Also I got a watch on the time of run. I check for line rake, tip weight, line tension, tail weight, nose weight, air flow cooling for the engine, and engine speed. After that is finished I USE Paul Walkers Trim Chart to trim the plane. It's simple to use and it's on paper. In fact I wrote an artical for our Club News Letter that out lined these steps. Have Fun! Scott

Yes, a very good question, do any of you experts have advice to give to us non-experts ( Yes I am a non-expert ) because a first flight is ( for me at any rate ) quite stressfull.
You spend hours building the thing, then you have to commit it into the wild blue yonder.......

My first flight is usually ups and downs to see if negative "G"s cause burping ,or to see if I get any wing dipping etc. It is usually with a full tank and I time the flight to see how long the run is on a full tank. The second test flight I usually go inverted and do inside and outside loops . I usually do the second flight on a windy day (15 MPH) so that if anything goes wrong I can wind fly the plane out of inverted positions and thus avoid inverted landings. Third flight full pattern.
Bigiron

>I'm going to try to keep
>this thread going with the
>question to all: what do
>you typically do on a
>first flight. The gamut ranges
>from straight and level the
>entire time, to a full
>pattern.

I usually go pretty far on the first flight. First is to check the wing level in level flight and basic speed. Then, inside loops. If those feel OK, then round 8's. followed by inverted. Same wing and speed check. Flip it back over, if everything is OK, or at least wrong in a safe direction (too much tip weight), squares, then overhed 8's. If everythign is still OK, I'll go back and do more-or-less a complete pattern with only one lap, and listen for the fuel consumption.

Last 3-4 airplanes were all close enough on the first flight to go through the whole thing as they were. The Infinity is back to the original trim settings with the exception of a flap tweak, and switching motors.

Currell,

It really depends on the engine/tank combination; if I have used the same engine/tank combo in another airplane and am familiar with it's running characteristics the after take-off and level flight - assuming the airplane is somewhat close to it's final trim, I may even do the entire pattern but at a slightly higer altitude than normal. That's the way it panned out for my New Shark .45, it flew well but had just a tiny inboard tip low attitude. All else seemed very good - line tension line rake angle - so I just did the whole pattern. I put in a tiny bit of trim tab and that help the wing angle some. I'm thinking that since the Shark uses an airfoiled rudder that it my be the actual cause of the slight inboard wing low situation?? If my trimming process proves that such is the case, then I think that I will leave things alone in trying to trim out the wing low situation because that can then lead to other trimming problems. While making a first flight I always check for line tension in level flight and above 45 degrees, along with control response both inside and outside. From there I just get out the trimming flowchart and start changing one thing and a time to see what happens. Then it's on to prop testing if necessary - then fine tune trimming again for the final prop selection.

Hope this helps?

Usually I fly combat on a first flight. I often run out of tested airplanes and have to delve into the unknown. If I'm lucky, I'll have some flight time after the match ends to do some eights to figure out what trim changes to make for the next round. As for stunt, I have too few first flights to have any real experience.

Randy, I'm looking forward to seeing your new plane and the Return of the Stalker.

LAST EDITED ON May-22-01 AT 00:29 AM (EST)

Howard,

>>Randy, I'm looking forward to seeing your new plane and the Return of the Stalker.<<

Well, I can tell you that on a pipe, I am really starting to like this engine. At 11,000 rpm with a 12x4 3 blade (pretty constant, rich, 2 stroke) it's giving a LOT of torque at about 5.3 to 5.4 second laps. Good, consistent run (when you don't get a hole in the exhaust system)

Currell,

Well, in my case it kinda depends on how it comes off the ground. If the engine is running the way it's supposed to and the wings are flat and line tension is good, I'll probably do most of the pattern. I usually leave off the reverse wingover on the first flight. <grin>

In the case of this plane, I did a full pattern the 3rd flight.

BTW. I flew it again tonight and 2 things happened. First, while it flies pretty well, there clearly isn't enough outboard flap. Am I ever going to calculate this right? The outboard flap is about 8% bigger than the inboard. I'm thinking it needs more like 11 or 12%. So, it's ugly wart time. Not too bad unless you hit the controls hard. Second: The hookup between the engine and pipe was a little funky to begin with. I wasn't sure it was going to work. It didn't. So, about 3/4 of the way through the 3rd flight tonight, The engine suddenly went rich. Not so bad it was going to fall out of the air or anything, but it dropped about a thousand RPM and just coasted along. Most of the power went too. (somehow, 6.0 laps always SOUNDS good). Anyway, got home and the joint between the engine and pipe was toast. It's what happens when you use an engine that doesn't have a header, I guess. So, I cut the pipe way back and am making a header for it tonight. What fun! Glad I know this now.

Still pretty happy on day two.

>Currell,
>
>Well, in my case it kinda depends on how it comes off the ground. If the engine is running the way it's supposed to and the wings are flat and line tension is good, I'll probably do most of the pattern. I usually leave off the reverse wingover on the first flight.
>
>In the case of this plane,
>I did a full pattern
>the 3rd flight.
>
>BTW. I flew it again tonight
>and 2 things happened. First,
>while it flies pretty well,
>there clearly isn't enough outboard
>flap. Am I ever going
>to calculate this right? The
>outboard flap is about 8%
>bigger than the inboard. I'm
>thinking it needs more like
>11 or 12%. So, it's
>ugly wart time. Not too
>bad unless you hit the
>controls hard.

You have more than enough differential flap area,particualrly given the high aspect ratio. Given that you sealed the flaps, I would look elsewhere for the problem, like somewhere in the roll/yaw coupling arena.

Brett,

Well, I tried everything I could think of. Adjusting the rudder, adding some rudder (temp), adjusting leadouts, tip weight. I just don't think there's enough outboard flap.

Well find out in about 30 minutes, anyway.

I usually run the new plane on the ground and flip it over to see if it's going to do anything funny inverted. You really can't tell until you get it in the air, but it doesn't hurt . . .

One ting I try to avoid is the new engine / new plane combo.
If at all possible, put a familiar and reliable engine / prop / tank set up into you new ship.

My last "first flight" I did a few insides, then flew it inverted and did a few outsides. At that point, my daughter didn't want to sit with my friends, so she sat on my lap while I flew lazy eights.

Works for me!

I close my eyes and grit my teeth. Actually, I do the level flight for a few laps, on a half tank of fuel, then a few climb and dives and finally a big lazy eight. All this to test line tension, engine reaction (4-2-4), wing level or low/high. Then after a few corrections I do a full tank full pattern. Sometimes I even crash. Great way to test construction techniques. Little humor there, darn little.

A lot of good info here, and I do a lot of the same. First and formost is are the wings level, which leads to line tension on in's and out's, and the One thing I can offer is this... When unsure of a new tank / engine combo, I was taught (By EddyR)to do a very elongated inside loop, keeping the plane inverted at the top of the circle long enough to find out if it will cut out. This leaves me enough room to recover if it does. You can make this loop longer and longer till your actually doing full inverted laps, then bring it down to level flight. Good topic!
EricV

Tried it with the tab on the wing. Looks OK. Now I can start actually practicing.

For those few of you attending the NW Regionals at Roseburg this weekend, see you there. It looks like we might finally get some decent weather for this contest.

The Nephew & I are leaving in half an hour. See you in Roseburg!
Nils

I saw Randy's new design in Roseburg, and saw it fly at least once. It looked quite good in all regards. The high aspect ratio wing is rather shocking, actually. The wind was fairly strong when he was flying it, but it didn't appear to be bothered by the wind any more than a short winged model. The flaps and elevator are "ball and socket" type, meaning that the LE of the flap is rounded and the TE of the wing is concave...like "))". Hinges are Robart's "hinge points". In theory, no sealing should be needed, but it is a LOT of work to make look good and fit well (they do). Randy chose not to fly, sharing the judging of Expert PA with Jerry Eichten, who also came to fly but took on the job when no others were available. Very commendable! Steve