Great Planes PT-40 wing modification

Since the PT-40 is a kit, the mod is simple. Make a new spar joiner with the reduced angle. Glue the root ribs in at the new angle, rather than the angle called for by the kit. Do this by proping up the wing tip the required amount and glue the root rib in verticle to the workboard. That way the root ribs will be flush to each other when you join the wing panels.

Washout....... anyone else got comments on that??????

David

I learned on a PT-40 and I wouldn't change a thing. It is perfectly designed for the task.

Cut the dihedral in half, leave the washout in. Washout creates an anti-stall characteristic that you want. This means the plane will fly slower without stalling.

Concerning trainer modifications: I built an Eagle and an Eaglet, both with

1/2" dihedral, and conventional (taildragger) landing gear. Both planes were good trainers and good sport planes.

Good luck and keep us posted.

Dr.1 Driver "There's a Hun in the sun!"

No matter how you decide to build it, there is no modification to the ribs. To build in the washout, you twist the wing and glue on the sheeting to hold the twist.

I do not consider myself an expert builder, and I'm still flying on a buddy box. Just relating my experience with a very similar kit.

Carrell

Dr1Driver wrote: "Cut the dihedral in half, leave the washout in. Washout creates an anti-stall characteristic that you want. This means the plane will fly slower without stalling." I agree 100%. I built and trained on the big brother PT-60. The Great Planes PT trainers are excellent trainers. Keep the washout and a little dihedral. You'll like it and have a great flying and stable trainer. Howard

I built one back in '91...and still fly it on occasion.

I also have TWO different wings.

I purchased an extra wing kit from Tower and I was glad I did. For the beginner, the standard wing is designed with a lot of dihedral and a fair amount of washout--and is for 3 channels. With this wing, half throttle is max (OS FP-40) for cruising or it'll climb out of site.

The other wing has ailerons, less dihedral and no washout--and is for 4 channels. It makes for a much improved plane with no problems at all. It's not aerobatic by no means, but is really a joy to fly.

The PT series of planes is a great place to start!

I don't know why most everyone thinks a big high wing trainer with low wing loading is the "best" type of plane to learn on. Here in Kansas these high wing, box fuse's, with huge tail fins blow around like kites in the winds that are normal for this area....almost ALWAYS over 10-15mph. We usually have lots of gusts and cross winds to deal with. Don't wait for a "calm" day cause there ain't any.

IMO, the "best" trainer for windy parts of the country are the Sig 4Star line of low wing planes, perhaps set up with a trike gear, especially the Fults nose gear. Leave off the outer spar at each end of the wing when building to have a little MORE wing loading. Or do what I did, and just add some weight to the wing tips at the CG point, which gives you the extra wing loading and makes the plane more wind proof.

Trainers for windy areas of the country benefit from;

A little more wing loading, especially if distributed outboard of the fuse. The plane will cut through the wind better and landings will be more predictable. I've seen plenty of those light loaded trainers balloon on approach when a stiff gust came out of nowhere, only to become kits again. And all that dihedral, which is so nice for floating a plane in on that perfectly calm day, just adds to your problems when that Kansas crosswind gets under it and sends it post-haste into the wheat field next door.

Trike gears, with some rake in the nose gear; they track straighter in crosswinds.

low wing planes with rounded fuses don't blow around as easily as high wing box cars.

Plenty of rudder, but smaller fins overall.

A low pitch prop gives you more thrust right off idle (nice when trying to get out of trouble) and also slows the plane's top end speed down some (which is also usually good when training)

It's not how much the plane weighs overall (within reason), but WHERE the weight's LOCATED. Weight distributed to the front/back and end of wing tips is best.

If you can learn on a high wing trainer you can learn on a Sig 4Star. I found them actually easier to takeoff, fly, and land than the high wingers.

opinions will vary, jk

P.S. washout is a method of getting the wing to stall first inboard near the fuse. Planes that stall at the outer wing first usually end up in a nasty spin. Box type wings (ie. trainers) don't really benefit from washout much, but rounded tips (ie. Spitfire) really need washout.

Most of us ain't in Kansas/Tornado Alley. :) You could fly a brick in some of the wind you guys have out there. :) Dr.1 Driver "There's a Hun in the sun!"

It ain't the wind I'm worried about. Any of you guys want to fill me in on cold weather engine starting procedures. We get two seasons in upstate New York (near Lake Ontario), winter and July 27th. :)

Higher nitro, say around 20%. Parallel your glow lighter - 1.2v, 2000-3000mah typical. Keep the engine warm in the car until just before you start it.

Jeez, when it gets that cold down here in the South, we just go build. :)

Dr.1 Driver "There's a Hun in the sun!"