Top Flite Gold Texan--Warning

Top Flite Gold Texan--Warning
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Top Flite Gold Texan--Warning - 7/6/2006 12:13:07 AM

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I know these kits are discontinued, but there are still some still out there in a box, so here is a warning to all would be builders. Do not use the listed CG in the manual--you WILL end up crashing the model. After two repairs, and some good advice from a fellow RCU'er, I learned that the proper CG--the one at which the model will actually fly well--is 5 inches back from the leading edge at the fuse--which is actually 5 inches back from the front of the fender well. This is almost a full inch in front of the listed CG.
The second time I tried to fly it with the listed CG (after the first snap and re-build), I had a very seasoned pilot try it. This guy could fly anything airworthy. He got it back down, but had to land so hot that we broke the CMJ retracts. After that, i did some research and found out that the best CG is actually forward of what is recommended. Since then, the model has flown exceptionally well.

Just thought I'd pass it on.

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RE: Top Flite Gold Texan--Warning - 7/6/2006 12:58:15 AM

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is this the at-6 that was crashed on the maiden flight from a stall that was a result of an unexpected lift off?
i remember reading a post about a year ago i think.glad you got it in the air this time and back down to fly again.maybe that cg was the reason for them to be discontinued

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RE: Top Flite Gold Texan--Warning - 7/6/2006 1:09:24 AM

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Thanks for the heads up. I should be test flying mine in a month or so.

Tony

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RE: Top Flite Gold Texan--Warning - 7/6/2006 4:04:52 AM

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I have a Hollywood Zero which is practically the same plane, I wonder if the CG is the same?

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RE: Top Flite Gold Texan--Warning - 7/6/2006 4:55:14 AM

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Yes, about a year ago is when I first snapped it on takeoff. However, I wouldn't classify it as an unexpected takeoff, as the saito 100 had pulled the plane for the better part of 150 or more feet on the ground, and the plane started lifting up on its own--not a steep climb at all, just a nice, gentle climb. Then, with just a TOUCH of elevator, the plane snapped left, and the rest is history. Anyway, move the CG forward if you haven't already. It will save you much heartache.
Don't know about the zero, sorry.

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RE: Top Flite Gold Texan--Warning - 7/6/2006 3:47:16 PM

BarracudaHockey

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Gordon Banks of RC Report always says "A nose heavy plane may fly poorly but a tail heavy plane will fly only once"

I always start a little forward of the reccomended cg and work my way back but I doubt I would have gone a whole inch, sorry it cost you two planes to find out.

< Message edited by barracudahockey -- 7/6/2006 8:01:45 PM >

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RE: Top Flite Gold Texan--Warning - 7/6/2006 4:41:44 PM

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Yea. What's weird is that I know a lot of people have built this plane, and probably flew it with the recommended CG. I wonder if somewhere along the line the manual got changed, and the recommended CG was printed too far aft?

Anyway, all is good now, and I hope to keep anyone else out there from going through the same heartache as me.

It was RCU member Paladin that helped me, and finally gave me the majic CG. Thanks again!

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RE: Top Flite Gold Texan--Warning - 7/6/2006 6:41:44 PM

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One problem with the T-6 is the amount of elevator throw - those are some LARGE elevators so check the # of inches up and down - you may be surprised!

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RE: Top Flite Gold Texan--Warning - 7/6/2006 7:59:48 PM

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Hangar 9's AT-6 Texan suffers from the same problem. The manual gives the CG location and says it's relative to the leading edge of wing. It's not; the distance specified in the manual is actually measured from the front of the wheel wells, which protrude 1.5" in front of the leading edge. If you do what the manual says, you end up with a plane that's very tail-heavy (which I learned the hard way and only got straightened out when I called Horizon tech support).

Also, if you're using Century Jet's AT-6 retracts, beware of a design flaw that means they'll bend or break on just about every landing. See http://www.rcuniverse.com/forum/m_4412764/anchors_4412764/mpage_1/key_jeffpro/anchor/tm.htm#4412764 for information on fixing those retracts.

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RE: Top Flite Gold Texan--Warning - 7/6/2006 9:22:51 PM

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Tailskid--you are right about the elevators. I have very little throw in them right now. I can do a pretty good loop, but if I pull full elevator, it will snap. However, that is much different than it snapping when I pull MAYBE 1/16 inch of elevator. I still need to take some throw out, and will probably introduce a little exponential (although I hate exponential).

Jeff. You are also right about the CMJ's. My retracts snapped where the main wire enters the strut. I just replaced them with the fixed gear included with the kit because I was getting disheartened by the whole deal and didn't want to sink anymore $$ into it. Now that it's flying good (finaly), I may indeed go back with some spring air, or other better retracts (definitely not CMJ's anymore!)

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RE: Top Flite Gold Texan--Warning - 7/6/2006 10:36:04 PM

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Couple of questions,
TO Jeffpro, so where do you measure for CG, from the front of the wells or from the leading edge if you were to draw a line to the cord along the leading edge?
Why does some of these planes snap at full up elevator and others don't and I'm speaking of warbirds? I have a CMP Corsair 50 and if I let it roll out before applying very little up elevator, it will take off very nice. If I apply up elevator before ground speed is fast enough, it will snap. Now I know I'll get all kinds of answers about thrust and so forth, but what I'm talking about is after I'm in the air, if I use to much up elevator, it will snap and that's at full throttle. If I apply less up elevator, then it will do a nice loop. It's just if I use to much up elevator that the plane will roll over instead of doing a loop.
Larry

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RE: Top Flite Gold Texan--Warning - 7/7/2006 3:11:23 AM

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Hello All,

After reading this thread I went and found my instruction book for my Top Flite AT-6 so I could make a note for the future when I ever get around to building it. In the manual it states that the CG is to be measured from a position on the leading edge directly in front of Rib #4 and the CG is located 4 1/4" back from that point. The plans show the beginning of the CG range on the aft side of the wing spar. That puts the CG measurement from the front of the Wheel housings at just over 5 3/4", and that is just the front of the range!

Thanks for posting this, you probably saved an airplane for me.

Regards,

James

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RE: Top Flite Gold Texan--Warning - 7/7/2006 2:10:57 PM

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On the H9 AT-6, you measure from the front of the wheel wells, which is about 1.5" forward of the leading edge. The manual says measure from the leading edge. The manual is incorrect. Horizon verified that for me (although they argued that the front of the wheel wells IS the leading edge), and the plane's performance in flight lends additional verification.

If you measure from the leading edge, your CG is 1.5" too far back, making the plane difficult to handle in the air. The plane flies like a dream when you measure the CG from the front of the wheel wells.

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RE: Top Flite Gold Texan--Warning - 7/7/2006 3:50:30 PM

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Wizzard
You're certainly welcome. That is the whole purpose of this post. And yes, although I said earlier that it was an inch forward, it was probably somewhere between 3/4 and 1 inch. Believe me, on a plane as short coupled as the Texan, 3/4 to 1 inch is HUGE. Good luck with yours. It is a joy to build!

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RE: Top Flite Gold Texan--Warning - 7/7/2006 9:38:16 PM

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quote:

ORIGINAL: Larry S

Couple of questions,
TO Jeffpro, so where do you measure for CG, from the front of the wells or from the leading edge if you were to draw a line to the cord along the leading edge?
Why does some of these planes snap at full up elevator and others don't and I'm speaking of warbirds? I have a CMP Corsair 50 and if I let it roll out before applying very little up elevator, it will take off very nice. If I apply up elevator before ground speed is fast enough, it will snap. Now I know I'll get all kinds of answers about thrust and so forth, but what I'm talking about is after I'm in the air, if I use to much up elevator, it will snap and that's at full throttle. If I apply less up elevator, then it will do a nice loop. It's just if I use to much up elevator that the plane will roll over instead of doing a loop.
Larry

what you are doing with too much elevater input is causing a high speed stall with the snap as the end result of the stall.stalls can happen at any speed not just when you fly too slow.a sudden large control input or a sudden change in direction can cause a stall and that is what is happening to you.to avoid the problem just reduce the amount of full elevater defection by moving the pushrod clevis firther down on the horn or move the wire in one the srvo arm.

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RE: Top Flite Gold Texan--Warning - 7/7/2006 11:04:06 PM

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To LarryS, yes this is the same plane (hollywood zero and AT-6), Topflite has you change just a couple of things around while building the T6 to get you a zero. C of G will be the same on both.
John

(in reply to aerowoof)

RE: Top Flite Gold TexanWarning - 11/9/2008 10:44:07 PM