Hello,
Brought a Twister home today and had some concerns regarding the fairly long nose, fairly short motor mounts, and lite ply doublers.  I will definitely use 1/8" ply for the doublers, but what about those engine mounts?  Seems like there would be a hinge point between the rear of the mounts and a point somewhere aft of the LE.  If I were to extend the mounts back to (past?) the LE would I gain rigidity in the nose to an extent that it would be worth the extra weight of the longer mounts?  Should I make 1/16" triplers that extend to somewhere near the TE?
I may mount a Fox .35 (please see related post in the engine section) on this so I'm a little concerned about vibration, etc.
As I have several profile kits in my immediate future, I would assume any suggestions would also apply to a SkyRay, Tutor, etc?
Thanks in advance.

Semper Fi,
Danan

I've built two Twisters, both Fox powered, essentially more or less stock, and they flew very well.  Yes do use good grade 1/8 ply doublers and run the engine mounts back.  Drill some holes in the engine mounts if you want.  Also use aluminum mounting plates under your Fox.  Make an adjustable weight box and adjustable leadouts.  Move the CG forward to 15% MAC, which is @ 1 5/8 back of the leading edge, and move the landing gear accordingly.  Put as block of motor mount stock, and a piece of brass tubing for the ends of the landing gear to go in.  I joined my flaps with a piece of coathanger wire so I could tweak them easier.

Draw a line through the CG angled 15 degrees forward of the vertical.  Where that line crosses the pavement is where  your wheels should touch.  For grass move them forward 1/2 -3/4 inch.  On my Twisters, I had two holes for the gear, and three holes for each plastic strap.  Just rotate the strap around the middle hole for gear forward or back.  So I could fly with good landings on short grass or on pavement by shifting the gear position.  I tried the pavement position of grass once.  The airplane would land beautifully, then tip up on its nose at the end.

I've used five ply on the nose. Seems to help. Also I extended the engine mounts back to the leading edge of the wing. I added half ribs and wing tips. Club members make the point that wing tips cut drag (any kind of wing tips). This plane has served me quite well for over a season using an FP40 set up as described in the engine section. I moved the elevator to the rear of the slot in the fuse (about 11/2 inches back) which is approximately midway between the Fancherized position and stock position. At Brodak's I came within 3 points of second place in beginners. Competing against more sophisticated planes and more experienced flyers with lots of medals stuck to their hats. The winner got a boot. I expect to fly intermediate next season with another Twister. Just built the wing. The old one is a veteran of the circle having crashed three times before I got the hang of it. Including 2 crashes that split the wing. Since those early on events, the plane has stayed together and been a great tool for learning. Must say, the plane is quite a sight tho, two reject colors of monokote on the wings, vinyl stick on stars, yellowed fiberglass reinforcing on the tail wheel, fuel spots... That was 35 points on the landing however. And a plus 30 in the overhead eights and horizontal eights. Now if I can stick those corners in the square... and line those loops up better. (Imagine that the loops are pulling down my score.)

The fox35 might work. A club member flew a stock Twister with a fox35 into Advanced (or Expert). But the man is a talent often mentioned in these forums for his work with electrics. A tamed LA40 might offer more reserve oomph. I wouldn't be afraid to fly this plane a tad on the fast side. My early prangs resulted in a large part from a misunderstanding of what a good stunt run is. Ran it way too slow and rich. The FP40 I use is a nasty powerful beasty. An LA40 would probably be easier to set up. Saw some Brodak 40s run at Brodak. Looked like a forgiving easy to use engine with a wide powerband. Not an FP40 powerhouse, but no doubt it would do the job. The low power approach (LA or FP 25...) means marginal to me. If the model is light... if the wind is constant and moderate... etc. etc. Well, the wind is often weird and changeable and a plane of reasonable weight moving at a decent speed can cover up some brain fade.

Rudderless, thanks for describing what a tripler is.  I thought a tripler was a very thin 1/16" 'doubler' that was extended to the rear of the wing, and then the doublers were glued to the triplers but only went about 1/3 down the root cord of the wing. 
So an example of a tripler is the cowl on a Shoestring stunter.  Now I understand! 

Danan