Top Flite Gold Texan
 

A while back, I had a post describing how my texan snapped on me during it's maiden--just feet off the ground. I finally got it rebuilt (actually, my dad rebuilt most of it for me). Anyway, beside the point. The CG was checked, double checked, and tripple checked. It was right on according to the manual that I had. Level as can be. We even had it marked with stickers, and I re-checked it again before the re-maiden today. Today I had a much more experienced pilot (30 plus years flying) do the test flight for me. With 35% exponential in the elevator, and throws set to minimum, he was moving the stick MAYBE a 32nd of an inch and it was climbing--and very touchy. The tail was waivering as it was climbing. Once high enough, he tried a loop to check out the elevator authority. With little more than 1/2 the elvator throw available, the plane snapped out of the top of the loop like nobody's business! At that point, he knew for sure that it was tail heavy. He was bringing it back in, and had me hit the throttle kill button as he was lined up with the runway. A very fast approach (to help the tail retain some authority) saw the plane touchdown at probably over 35 Plus MPH. Not a hard landing at all, but fast. One CMJ retract snapped the strut in half, and the other ripped the leading edge off of my wing. Very sickening to see the 280 dollar retracts fall apart like that! Other than wing damage, all was ok. I can have it fixed in a matter of a few days. This time, I'm going to do the unthinkable though--I'm going to set it up for fixed gear. I know, don't shoot me. But, it will allow me to beef up the wing more, and shed about a lb of weight--most of which is behind the CG.

Here is my real question--Does anyone out there know of a mis-printed CG for this plane? I don't think the recommended CG is even within the flight envelope of this plane (or, it just barely is!). With the leading edge peeled back, I could see the spar (which, by the way, was unharmed--thank goodness). The marked CG is about 1/4 inch behind the main spar. I'm going to move the CG up to the spar at least before I fly it again. Has anyone else had this problem with this plane? If anyone out there has this plane, could you do me a HUGE favor and check to see where you have it balanced? I just absolute love this plane. I built it with the flaps and everything, and I don't want to give up on it. Once we get it to fly right, then I'll have my friend teach me how to fly it!

I've been flying for over 1 1/2 years now, and am a pretty good sport pilot, but I have a fever for warbirds, and want to learn how to fy them badly--especially this one that I put over 100 hours into building!

OK, thanks for any information that you have.....

RE: Top Flite Gold Texan
 

I built one for a friend but its been too long ago to remember the CG. I usually build according to the instruction and the first flight it was slightly touchy on the tail and snapped on a slow landing. We moved the cg forward and it helped. I would go to 1/4" forward of the spar. Its much easier handling a nose heavy bird! Also check your washout on the wingtips. If they are not equal, you will have 1 wing stalling before the other causing a snap. Good luck!

RE: Top Flite Gold Texan
 

Thanks for the tips! I was going to move it to at least the spar (about 1/4 inch forward of what it is now), but maybe even further? I'd be ok with that too! I'm pretty sure the washout is good. I used the jigs, and they were glued to the table, and the wingtips were glued to the jig while I sheeted it--locking in the washout. I was VERY careful of this point during the build! When it was flying, it tracked very nicely! Just too touchy on the elevator. Those CMJ retracts are a real POS!

RE: Top Flite Gold Texan
 

There is a website around somewhere that offers a little application that does CG computations. It's dead simple to measure out the few things that're required. It appears to me that the application is doing all the formulas that're required. I used to design my own CL stunters and RC gliders and kept a bunch of the paper work from them. I ran a couple of those old plans' measurements through the application and it gave the same answers I'd worked out years ago. So it's gotta be right, right? .... chuckle....

Those formulas work like gangbusters.

RE: Top Flite Gold Texan
 

OK, I'll look for that website. Anyone out there know the link right off? I don't know enough to work it out myself. I mean, I know about 25 % of chord, yada yada yada, but the wing is polyhedral--tapering toward the end, so figuring out the mean chord would be a nightmare for mathmatically challenged minds such as myself!

RE: Top Flite Gold Texan
 

I built one of these last winter and it is one of my favorite planes to fly. I just checked the plans and instructions and it says 4 1/4" from the leading edge of the center section of the wing not the wheel well. That puts it just on the back side of the spar. My plane flies very good. Does not snap at all with elevator alone. Elevator should have 7/8" on high rate and 5/8' on low. I wish Top Flight would kit this plane again because I like it so much. Good luck Erik.
By the way, My plane balanced right on the recomended CG. I did however add a couple of ounces just to make it a bit nose heavy.

RE: Top Flite Gold Texan
 

Well, I thought I had it at 4 1/4--I did as best as I could measure. However, on my Texan, this puts it about 1/4 inch behind the spar. Mine definitely does not fly very well at all, and this was with an experience pilot. Did you use the retracts, or fixed gear? What (approx) is the all up weight of your plane? It seems like mine is close to 10 lbs (I can't remember exactly, it was a long time ago when I weighed it).

Thanks again!

RE: Top Flite Gold Texan
 

Sorry you are having trouble with your Texan. Mine flies great after sorting out some engine problems that got me in trouble a few times. I tore the wing in half in a brilliant dead stick landing. Ground handling is not great and the century jet gear has taken a beating. They replaced the struts on mine for about $70. How much does your Texan weigh? Mine is around 10 lbs. I think it was under 10 before the rebuild. I read a post on RCU a while back and they said the CG printed in the manual is way off. I went at least 1/4" maybe 1/2" forward of the suggested. I needed about 4oz of nose weight with a Magnum 91 4stroke and a heavy hub. I don't have the gear in right now, I need to send it in over the winter for work, so I can't tell you exactly what the balance point is. Better luck next time.

RE: Top Flite Gold Texan
 

Thanks for the info, Irb! I'm leaning more toward moving it forward a full 1/2 inch, or at least 3/8! My Plane is just over 10 lbs, I think. That is with split flaps and CJM retracts. I won't have the struts replaced on the CJM's. I only gave 60 bucks for the CJM's to begin with. I would have never bought them for full retail price! The were NIB when I bought them, though! I'll probably replace the struts with some other wire--maybe robart or spring air and use the setup for another plane--yet to be decided.

I figured it was the case--the printed CG being off a bit. With such a short nose, it takes a lot of weight to move the CG forward! I'm flying it with a saito 100, which is almost exactly the same weight as the magnum .91. I'm thinking about moving the throttle servo to the firewall, and some other mods to re-arrange weight, instead of adding dead weight! I'll add enough of that when I go in and reinforce the wing for the main gear :eek:

thanks again!!

RE: Top Flite Gold Texan
 

If I remember correctly, my balance was right at the edge of the main spar as well. From that I
had my finger more toward the leading edge so in essence I probably moved the cg 1/8" forward.
I am running an OS 91 and had to put alot!!! of weight in the nose but she flew good (until I
landed and the d$@# retracts ripped out and took one half of the wing with it[:o] ah well. Pretty
plane though, it was a joy building it.

SVX

RE: Top Flite Gold Texan
 

2slow, Mine was ballenced at the when I test flew it, and it was a hand full on that first flight. Due to the engine, not the CG. Since then It has had 1/2 a dozen engines on it and to be frank I'll do a field ballence. But when switching engines I make sure the wt forward of the firewall is the same by adding lead if need be. Its also picked up some (ok alot of feul soaking) in the nose also since day one. If you want I'll put it on the ballencer to see what we get.

Mine is very active on elevator and vary slow in role. It will do huge loops, and has been used for combat with my son and has been very predictable,

Joe

RE: Top Flite Gold Texan
 

Joe, thanks again for the reply. You were most helpful when I first crashed it. If you have time, and don't mind, then I'd appreciate knowing where you balanced it.

Are you saying that you didn't have enough motor on it to begin with? What are/were you flying on it? I have a saito 100 with a 14 X 8 MAS prop, and it seemed to pull the plane pretty well once in the air. I just don't think the elevator should be so touchy that it snaps out of a loop with about 1/2 or 5/8 inch of throw! What do you think?

RE: Top Flite Gold Texan
 

2slow, I can’t do it till the weekend (ho, ho, ho) but I’ll get to it. My At-6 is a hollywood zero and was built because my son and I will chase each other around the sky. It started with a K&B .65 which ran like _______. I replaced it with a Super Tigre S-61, it flew it well (on the wing). But in a dog fight it did not take much twisting and turning to run out of energy and altitude. So I bumped it up to a Super Tigre S-91 and it helped with the energy loss. But my son was flying a P-51D which was very stingy with energy. I had a OS 1.2 4c on the shelf and that made it a whole new plane. Since then it has broken in a second and third 1.2 4c, an ASP .80, and a OS 1.08 FSR. Radial engines leave a lot of room to fit a variety of engines.

Your saito 100 should be plenty of power. Mine was very snappy while flaring and it would lead right into the “AT-6 bounce”. I solved this by raising both ailerons by three or four turns.

About the landing gear and the “AT-6 bounce”. It is something that the Texan is prone to and with plywood as the front mount you will be replacing it a lot. I build all of my retract mounts out of maple. And only maple! The problem with ply is that no matter how well you glue it in, the ply is only as strong as the glue between the plys. Quite often when you rip the front landing gear mount you will notice that one or more of the layers of ply stay with the plane. That is proof positive that the ply was a major player in the final failure.

I’ll also check my elevator throw. Aileron is all I can get.

Joe

RE: Top Flite Gold Texan
 

Cool, Joe. thanks--I'll be looking forward to your reply.

BTW, I have an ASP .91 2st that I've kicked around putting on the plane. Do you think this would be better? It is currently in an ultimate that would be a good home for the 100--would just be an engine swap!

Thanks again!

RE: Top Flite Gold Texan
 

My TF AT-6 is a great flier but will drop a wing and snap with elevator at slow speed. CG is at 4 1/4 inches from the edge and total weight is right at 9 lbs. with robarts.

RE: Top Flite Gold Texan
 

My TF AT-6 is a great flier but will drop a wing and snap with elevator at slow speed. CG is at 4 1/4 inches from the edge and total weight is right at 9 lbs. with robarts.

RE: Top Flite Gold Texan
 

sweet looking plane--I like the white!

I think I'm going to move my CG up to about 4 inches and try again. Hopefully getting rid of the retracts will help me do this, and also bring the plane back down to under 9 lbs--maybe even close to 8 lbs, which would be awesome!

RE: Top Flite Gold Texan
 

There is an old thread on this site about this plane, but can't find it. It mostly said what you have already found out (the hard way) which is to move the CG forward to the recommended extreme. Century Jet retracts for this model don't have a good reputation, the Robarts seem to fair better. As far as engine, any .90 to 1.20 4 stroke seems to be good (move weight around for balance), and a .75 to .90 2-stroke is the ticket (if you like 2-stroke in a warbird).

RE: Top Flite Gold Texan
 

2slow, I got 5in from front of wing wheel fenders to the CG. I also checked my elevator throw I have 1.25inches of up and 1inch of down with 20% of expo.

Get your hands on a incidence meter, set the plane so that the wing center just out side the wheel fenders is set at zero (both sides should be at zero at WING1). Then measure the incidence of the wing just inside of the ailerons (it should be negative) on both sides, add the two together and I’ll call it WING2. Next measure just on the aileron with the radio on, add the left and right together ( just like for wing2) and call it wing3. Do the same for the tip of the aileron, add them then call it wing4. WING2, 3, 4 should be = (+- half of a degree.

Then measure the verticale stab right and left. Obviously these two should be the same, if not it should be reflected in the aileron measurements. This measurement should be negative (the stab sets the path the plane flys and the wing needs to be positive to produce lift). Looking at these numbers you can tell where your plane is bent.

The engine incidence is tough because I’ve not found a setting I’m happy with on mine yet.

Got to go piece, love and joy calls

Joe

RE: Top Flite Gold Texan
 

Joe, once again you've been a wealth of info. Thank you so much for taking your time to help me out here. I'll probalby get the wing fixed sometime early this week, and me and my dad will put it on the incidence meter and take those measurements.

Thanks again....

Have a wonderful Christmas

RE: Top Flite Gold Texan
 

2slow,

I have this bird on my shelf for a future build as it is one of my favortie planes and I am going all out on it. It is quite by accident that I even have it as Top Flite had quit offering it and I found it at Tower Hobbies two years ago. I think they found a few they didn't know they had. Anyway, in preparation for this plane........believe me I'm a kit builder not an ARF fan........I bought a H9 AT6 and when balancing it they were not clear on where to do it so I called and they told me that the measurement was right at the fuselage from the front of the wheel well edge, which would put it significantly forward of where it would be if you measured from the leading edge. Also, it was balanced inverted with retracts retracted. This plane flew great from the get go with absolutely no tip stall or unstable characteristics. It is about the same wingspan and weight as the TF AT6 which is, what I said earlier, why I bought it to train on.

Hope that helps some,
Andy

RE: Top Flite Gold Texan
 

RCandy....
This kit will take you in the neighborhood of 70 to 100 hours, depending upon how scale you're going to get with it, and how fast you work. I built split flaps and all.

I've got mine back together now. I've installed the fixed gear. I also moved the CG forward to where Joe recommended--5 inches back from the wheel fairing--right next to the fuse. THis placed the CG about 1/2 to 3/4 inch in front of where it was to begin with--which is where the book recommended. The plans even have on them where the recommended CG is, so where I had it to begin with was no mistake--it was right on where the book and plans recommended. However, it was wrong, so beware when you build it.

Build it as light as possible in the tail. The short nose on this plane makes it almost impossible to move the CG fore. It took us 8 ounces of weight placed in the cylinders of the dummy radial to get the CG to move forward as much as we moved it. We put BB's in the dummy radial cylinders, and poured thinned epoxy down in them to glue them in. Worked like a charm, but pretty much put all the weight back on that I shed by getting rid of the retracts.

I haven't weighed it since we did all the work on it (today), but before (with retracts, and without nose weight) it weighed in at around 9 lbs. I'm sure it's about that much now, maybe 8.5 lbs if I'm lucky. I'm farily sure this is quite a bit heavier than the H9 arf version. I have the H9 mustang arf, and it's pretty light weight. This kit builds heavy--which, as we all know, makes flying it much more of an art [8D]

Good luck with the build. I really enjoyed building it. Hopefully I can get the balance issue worked out before it destroys the plane! It's such a beautiful plane. If you opt for the split flaps--get ready, and be patient!

RE: Top Flite Gold Texan
 

2slow,
Thanks for the tips. I'm not going to start it for awhile as I have a TF C182 in progress right now. I also plan on building the TF P47 and DC3 both of which I already have. I have been accumulating kits for when I retire because I'm sure that I won't be able to spend the money then like I can now. Yes, I will be doing flaps, retracts and a sliding canopy so it will be on the heavy side.
Again thanks for the tips and please, please let me know what you find out on the CG so I (we) can benefit.

Andy

RE: Top Flite Gold Texan
 

Here are some pics of the new Texan in progress. Any building problem areas that need addressed please let me know. This is the first to be done here. More pics in the works.....

RE: Top Flite Gold Texan
 

Flyboy, have I got a list of fixes for you! Please keep in mind that this is a hobby and I’m not saying you have to do any of this stuff but here goes.

First off you retracts are the robart plastic ones:

- NEVER buy retracts that have plastic mounting ears and frame!
- On those gear the piston is only 3.8 diameter making the power of the cylinder marginal
- The cylinder is set up so that the output arm is on the deploy side of the cylinder so any thing jams on the way up (on retraction) can’t be over come on the way down (deployed)

I was given a set of the retracts you have and used them for about 14hr of flight time. In that time I had three failures to deploy that were un explainable because as I lifted the plane from the belly landing the gear popped right out.

AT-6’s have an inherent bounce on touch down, I personally thing it was intended by the designer to teach new war bird pilots the virtues of wheel landing. What ever the reason there is a bounce and once you find it it will remove the wheels from the airplane given enough time. To add to your problem the ribs are unsupported because the first thing that happens is the plastic wheel fender breaks free of the ribs. I rebuilt my center section about 25hr of flight time ago because it was getting to loose goosy and I was afraid I would loose the wing. Nothing like putting a perfectly good wing in a band saw! I doubled each landing gear support rib with 1/64 ply over the entire rib and rebuilt a new center section with the doublers that came with the kit. I also replaced the front landing gear mount with a maple one cut to fit in the same location.

Lastly put some balsa on the top of the wing bolt tab then carve it to the contour of the top ribs. I’ve had the wing bolt tabs break free from the spar behind them. While alittle CA will fix it with the balsa it will never happen.

The center section of this kit (an excellent kit) is the weakest point in it. You are not to far alone to affect most of these changes before you move on. It’s a hobby do what you want and have fun!

If it don’t fly it wont ketch my eye.

Joe