Building the FT Spitfire
- Thread starter Flyingshark
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- spitfire
Flyingshark
Master member
Mine balanced a touch nose heavy on the middle of the spar. Good luck on the maiden!
Cobra1365
Active member
Maidened this morning. Did not go so well.
The airplane wanted to roll left. Added right aileron and found it had no effect. So compensated with some trim and rudder. It also wanted to dive. Compensated for this by holding a bit of up elevator. The roll kept worsening. Trying to line it up for landing, it got to the point I was all over the controls. Went into the alfalfa...flat. But, still took the gear off and broke the prop.
When I got to the airplane, I did a quick control check. I immediately noticed the issue. Up elevator caused the left side of the elevator to deflect considerably more than the right...thus causing the left roll. It acted like an elevon.
everything else seemed fine (again, other than the gear and prop.
I think I’ll add a Stiffener between the two sides of the elevator. I’ll probably increase the throw on the ailerons a bit as well.
Oh well, they’re foamies!
The airplane wanted to roll left. Added right aileron and found it had no effect. So compensated with some trim and rudder. It also wanted to dive. Compensated for this by holding a bit of up elevator. The roll kept worsening. Trying to line it up for landing, it got to the point I was all over the controls. Went into the alfalfa...flat. But, still took the gear off and broke the prop.
When I got to the airplane, I did a quick control check. I immediately noticed the issue. Up elevator caused the left side of the elevator to deflect considerably more than the right...thus causing the left roll. It acted like an elevon.
everything else seemed fine (again, other than the gear and prop.
I think I’ll add a Stiffener between the two sides of the elevator. I’ll probably increase the throw on the ailerons a bit as well.
Oh well, they’re foamies!
A popsicle stick also works great.
Cobra1365
Active member
That’s what I used.
Also changed the tail wheel to a fixed gear and shortened it up.
Flyingshark
Master member
Repaired the Spitfire. The damage was more extensive than I'd realized. A lot of hot glue and packing tape did the trick, and she's ready to fly again.
Cobra1365
Active member
I think I figured it out. After I removed the tail assembly, I held up the fuselage and I could see a gentle warp all along the fuselage to the left. With the tail on, it was not as noticeable, as the eye went to the very stab.
I‘ll rebuild the fuselage and tail feathers and give it another go.
I‘ll rebuild the fuselage and tail feathers and give it another go.
Cobra1365
Active member
So, maiden part ducks...or is this three? Anywho! Flew much better. But, still wanted to roll left. Full right trim on aileron and rudder. Pulled the gear off on landing.
Pretty sure I have it figured out now. The wing has a very slight twist to it! I reused the wing from the first go and just rebuilt the fuselage. I didn’t notice it until my buddy held it flat At eye level and I looked at the bottom of the wing. I could see more of the right wing than the left. That slight increase in angle of attack caused more lift on that side resulting in the roll to the opposite side.
G to be pretty windy for the next few days. So, I’ll split the wing and straighten it.
Pretty sure I have it figured out now. The wing has a very slight twist to it! I reused the wing from the first go and just rebuilt the fuselage. I didn’t notice it until my buddy held it flat At eye level and I looked at the bottom of the wing. I could see more of the right wing than the left. That slight increase in angle of attack caused more lift on that side resulting in the roll to the opposite side.
G to be pretty windy for the next few days. So, I’ll split the wing and straighten it.
Flyingshark
Master member
I second that. With a little digging, you can still use the same servos and control horns. If the wing is twisted, it's probably best to deal with it by making a non-twisted wing instead of trying to cut and bend the wing you already have to get the twist out. Assuming you have enough foam board to build another set of wings and that little bottom piece from the fuselage that goes under the wings.
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Cobra1365
Active member
Yep...that’s what I ended up doing! I had one precut that I forgot about! Derp! I messed up a cut originally and cut. Second one. The messed up cut is cosmetic. So, that’s the one I’ve used now.
As I said, weather is going South here over the next few days. So, I’ll take the time to finish it up.
Thanks!
As I said, weather is going South here over the next few days. So, I’ll take the time to finish it up.
Thanks!
Cobra1365
Active member
SUCCESS! Sorry, no video. But I rebuilt a new wing and shortened up the gear a bit. Airplane took off with no problem. Still needed some right trim, but nothing compared to previous flights. Elevator has plenty of authority. I need to give it more aileron authority though. I also think I’m going to change props. I flew for less than 3 minutes and the batteries were down to 3.8/cell when I landed. I’m running a 20 amp ESC with a GTMax 2215/09 motor swinging a 10x4.5 prop. Battery is a 3s 1300.
Yay! Are you sure the pack was charged up all the way? Even at full throttle the whole time you should be getting more than that... I have a 9x6 in mind and it gives really good performance!
Cobra1365
Active member
Yeah, had a full charge! I’m throwing a 9x6 on it. I don’t anticipate a lot of difference though. Diameter decreases. But, pitch increases.
The Fopster
Master member
Mine flew way better on 9x6. You may be surprised. Good luck!
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