Top flight Texan Maiden--bad

Top flight Texan Maiden--bad
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Top flight Texan Maiden--bad - 6/11/2005 4:06:39 PM

2slow2matter

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Joined: 8/25/2004
From: Springtown, TX, USA
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OK guys, help me figure this one out. First, as stated before, this was my first warbird. I have flown my dad's .40 sized Corsair, and it was a handful to take off and land, but I was able to do it. The landing of it would have been flawless, except that it rolled off the end of the runway, and onto the rough grass and nosed over. So, I felt comfortable flying this big T-6 that I had built. Well, after warming up on a big stick, I was set and ready to go. Everything was balanced per the manual, and looked trimmed on the ground. I lined up, and starting forward with the throttle. It was tracking straight down the grass runway. I kept increasing power. The tail came up--pretty. Rolling on the mains, and gaining speed, it lifted off on it's own--no elevator input from me. Once airborne, it started to drift a little to the right. By this point, I believe I was at full power (saito 100 swinging a 14 X 8 prop). I began to give a little elevator. I tried to be careful of elevator input early in flight because I know these things can snap. Well, with what seemed to be little elevator at all, the left wing dropped, the tail came up over the top, and the thing went into the ground at full throttle, nose first, from about 10 feet or less). It happened so fast. Things went from so pretty, to so ugly so fast that I was numb. I'm thinking that it may have snapped, but why? It had enough airspeed to lift off on it's own, and I didnt' think I gave it that much elevator. What did I do wrong? Hopefully someone can shed some light because I'm going to rebuild this thing (only the nose was hurt--nothing else) and try it again. I would like better results next time. The build was good. I feel comfortable in the build process. I'm pretty sure this was pilot error, but what error? I wasn't using flaps.
Help, please. Thanks..

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RE: Top flight Texan Maiden--bad - 6/11/2005 5:28:42 PM

captjack

Posts: 89
Joined: 2/28/2003
From: bow, NH, USA
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sounds like the plane stalled and snap rolled on you.unless there is a trim problem,which there could be on a new plane.the drobbing of a wing tip is the first sign of a plane stalling.I would check the wing and stab incidenes to see if they are the same,also i usually balance new scale planes at the forward cg limit so it is a bit nose heavy.If this plane lifted on it's own does not mean that it had attained flying speed.should have leveled off first to let the speed build before starting your climb,I know hindsight is 20/20 but a stall can happen at any attitude and at any speed.high speed stall is just what it sound like.a stall at high speed caused by a large surface deflection very quickly causing a sudden change of airplane attitude resulting in a high speed stall and snap.

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Post #: 2

RE: Top flight Texan Maiden--bad - 6/11/2005 5:54:29 PM

Sturtz

Posts: 1519
Joined: 9/22/2004
From: El Reno, OK, USA
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Not that you made this mistake,,, but the last time I saw a warbird maiden death the way you discribed ...... the guy was of course,,, nervous and excited. Long hours of detailed work . Ailerons were reversed.

< Message edited by Sturtz -- 6/11/2005 5:55:43 PM >

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RE: Top flight Texan Maiden--bad - 6/11/2005 5:57:00 PM

the-plumber

Posts: 1390
Joined: 8/3/2004
From: East Cobb County, GA, USA
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The bit about

quote:

ORIGINAL: 2slow2matter
the left wing dropped, the tail came up over the top, and the thing went into the ground at full throttle, nose first, from about 10 feet or less).

is a little bothersome.

If it had been a stall you would normally have seen the left wing droop and the tail tuck under, after which the model would normally flop over on it's back, and you know the rest.

Your description sounds more like the elevator servo was reversed.

Everyone knows CATS : controls, antenna, trims, switches.

It's the 'controls' part that sometimes bites ankles on flight tests.

For 'controls', use a mantra :

Roll right, raise right not left,
Right turn, right side,
Pull up, pop up,
Push for noise.

Pretty self-explanatory.

I've seen big name "flyers" launch finely built scale models at Scale Masters Qualifiers with ailerons reversed because they were in a hurry and didn't take time to do the "C" in CATS.

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RE: Top flight Texan Maiden--bad - 6/11/2005 7:46:11 PM

grbaker

Posts: 2455
Joined: 12/12/2001
From: La Porte (near Houston), TX, USA
Status: online

quote:

Your description sounds more like the elevator servo was reversed.

That's the first thing I thought of also.

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RE: Top flight Texan Maiden--bad - 6/11/2005 9:10:22 PM

2slow2matter

Posts: 2404
Joined: 8/25/2004
From: Springtown, TX, USA
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Thanks for the tips. I just checked the elevator servo, and it was not reversed. Pulling back on the stick causes the elevator to deflect upward. I know it's weird that the tail came up and over. That's what has me so perplexed. I was hoping that someone had seen this before and could enlighten me. maybe it wasn't ready to fly yet (speed wise), but as mentioned before, usually snaps end up with a wing dropping followed by the tail. This plane should be fairly gentle to fly. My plane weighed in the neighborhood of 10 pounds. Between 9 and 10. It was 9.5 before I added 6 oz of weight to the nose. The saito 100 shouldn't have a problem flying it, and that is a lot of wing surface (70 inches). However, it does taper, and I'm not used to a polyhedral wing yet. Keep em rolling. I need to figure out what went wrong so I don't have a repeat performance! I know there will be a lot of growing pains in learning to fly warbirds, and I can handle it. This one was a tough pill to swallow (mainly pride, since the plane is relatively easy to fix). One good thing about it--now I know I can beef up the front end quite a bit and still be within the balance points!

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Post #: 6

RE: Top flight Texan Maiden--bad - 6/11/2005 10:29:20 PM

the-plumber

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From: East Cobb County, GA, USA
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quote:

ORIGINAL: 2slow2matter
Thanks for the tips. I just checked the elevator servo, and it was not reversed. Pulling back on the stick causes the elevator to deflect upward.

Hhhmmm . . .

Presuming the CG didn't shift and the other controls are as they should be, I'd look at the firewall and engine mount. Might be the firewall pulled loose or the motor came loose from the mount, allowing the thrust line to shift down.

OTOH rebuild the thing and try again. Do make sure the control throws are per the book and that you don't have excessive travel volume. Also do a thorough range check with the engine at full tilt.

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Post #: 7

RE: Top flight Texan Maiden--bad - 6/11/2005 10:55:15 PM

2slow2matter

Posts: 2404
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From: Springtown, TX, USA
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Plumber, thanks

I wondered if some of the stick on weights that I added to the nose might have come loose on me, and cause the CG to shift. However, even without those weights it was still within the recommended. Who knows... I had only added the stick ons for temp, and was going to epoxy them in when I found the CG that I really wanted. I wondered about the firewall coming loose as well, but I didn't hear any pop or other noises before the incident. Still could have happened, I suppose! I did a range check, but not with the engine running. I should have, but I didn't have anyone else to help hold the model while I walked away. I didn't have any teather, either. Well, it will be rebuilt. I just looked at it. Looks like a new firewall, rebuild the forward crutch some, a little work to the forward wing saddle, and a new F-1 ring which can all be rebuilt with the plans. Just sucks that after all of this time, I'm not flying it RIGHT NOW! I really didn't like how the firewall was held on by those stringers anyway. That could have been a cause of defect. I had beefed it up by adding epoxy and balsa around the firewall, but that only secured it to the sheeting. On the rebuild, I think I'll use a little larger stringer, and then glass the firewall in after I'm done. And, the firewall will probably be about double the thickness

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RE: Top flight Texan Maiden--bad - 6/12/2005 11:13:25 PM

Blue_Moon_

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From: ., SWEDEN
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build........rebuild........build........rebuild.......build......rebuild----will the insanity ever end?

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RE: Top flight Texan Maiden--bad - 6/13/2005 12:24:49 AM

rifraff

Posts: 159
Joined: 1/4/2005
From: escondido, CA, USA
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sorry to hear about your plane

It sounds like it stalled.. wich way was the wind coming from .did you take off towards or away from the wind
if you want a nice warbird that handles like a trainer get the modeltech p47 or the great planes JU-87 Stuka,they both handle very nice and can use that saito 100 you have
good luck and happy flying

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Post #: 10

RE: Top flight Texan Maiden--bad - 6/13/2005 12:33:19 AM

E Henry

Posts: 36
Joined: 11/9/2004
From: Plymouth, IN, USA
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I maidened my top flight Texan about a month ago. I am still new to warbirds and trying to figure them out. I am using a ST .75 and I kept the plane light (no retracts, etc.) I just wanted a Sunday flier the would give me no problems. On the first flight I applied throttle slowley and did my best to keep it going striaght. At about 1/2 throttle the plane start to lift off the ground and I knew I did not have enough air speed. I gave it full throttle and was able to pull it thru. After flying it I noticed the trim was pretty close but was unsure why it lifted so quickley. Since I have gotten the hang of taking this plane off I apply just a small amount of down pressure on the stick and it keeps the plane on the ground until I I am sure there is enough speed. This is a very fun plane to fly and landing could not be any easier. good luck with your rebuild Erik

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RE: Top flight Texan Maiden--bad - 6/13/2005 12:42:38 AM

captjack

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From: bow, NH, USA
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Ehenry,
have you checked the incidence of the wing and stab?if so what were they.if the wing has more incidence than the stab it will want to lift off before it should.

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RE: Top flight Texan Maiden--bad - 6/13/2005 1:52:57 AM

E Henry

Posts: 36
Joined: 11/9/2004
From: Plymouth, IN, USA
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CaptJack, No I have not checked the incedence. The plane flies very good. If the incedence were off enough to make the plane lift off early, wouldn't it need a fair amount of down trim for level flight? The plane only required minor trim adjustment for level flight. Like I said I am new to warbirds and still learing. If the incedence is off, what changes can be made to correct? Thanks for your addvice

< Message edited by E Henry -- 6/13/2005 2:12:41 AM >

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RE: Top flight Texan Maiden--bad - 6/13/2005 2:10:37 AM

Cyclic Hardover

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From: New Mexico, USA
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I have a fw warbirds and manyof my buddies also from the little ones up to the big ones. Warbirds are not forgiving. With those short noses and moments its easy to get one tail heavy and thats all she wrote. Your theory on the weight coming loose could have happened on take off and immediately going tail heavy after lifting off is very possible. I saw a guy once try and land a giant scale P 51 that was tail heavy he was all over the place and finally pancaked it on the runway just to get it over with.

From everything I have ever done or seen, warbirds need speed and a shallow liftoff. If you just pull it up off the ground , it can flip on you.
You know how you see guys landing with some stick or something and they have these high bounces, then decide to rap on the throttle and go around and try again? Can't do that on a warbird or again , it will flip.

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RE: Top flight Texan Maiden--bad - 6/13/2005 2:10:41 AM

2slow2matter

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From: Springtown, TX, USA
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E-Henry,
It is quite possible that my pre-flight ground trimming set the elvator too much on the positive side. This would have made it lift off too early. who knows. I'm sure of two things--it crashed, and it will be rebuilt in 10-15 hours worth or work. When I try it again, I will most likely make it nose heavy by at least 1/4 inch or so, and set a little down el