I am learning how to cut foam wings and I made one for my BB24's, after all it is a small wing and I wouldn't loss a lot of foam making mistakes
After trying 2 or 3 times I could get something like a wing, reinforced it with a 2mm fibergrass rod and a lot of package tape and tried to fly with it.
To my surprise it worked very well, very distinct feel from the UC wing. I switched the 2 wings several times and I am very happy with both, it is like I have 2 models instead of one.

Gino

Originally Posted by jackerbes

Spike,


And it has all survived a number of hard crashes with a KFm3 wing (too freakin' responsive and fast for my skill level) and several with a KFm2 wing (the wing that matches my skills pretty good).



Jack

What difference in flight characteristics do you see between the KFm2 and KFm3 wings? Does the KFm2 give better lift and slower speeds?

Steve.

My KFm3 has 3/4" (per side) dihedral and ailerons, the KFm2 has 2" (per side) dihedral and no ailerons.

The KFm3 is a little faster and less stable (but not unstable) in straight and level flight, it requires more or less full time use of the controls. That constant use of the controls becomes a subconcious thing over time. If you ask a good flyer to describe exactly what they just did with the sticks after an arcane series of maneuvers, they probably won't be able to tell you. And the KFm3 with the nearly full width ailerons and a pretty close to flat wing has a *fast* roll rate. It was too twitchy for me, turns kept turning into rolls...

The KFm2 is a little slower but not a lot. If there is a big difference in the lift I've not noticed it. By the theory of the wing designs, the KFm3 airfoil actually has a little better lift and lower stall speed than the KFm.

The KFm2, built with a decent spar, is a good wing choice for a more or less advanced RET trainer. It can be looped and rolled with elevator and rudder (a lot of tail wagging on the rolls). And it can be put into hard dives and turns as you start getting more aggressive at the controls. It excites those of us that have not mastered higher performance aircraft. It is not *too* boring for those that have.

If you build with a KFm2 or 3 wing, I reccommend overpowering the plan a little and flying it throttled back rather than going with just enough power to get it to fly nice. That is a much more versatile plane in the long run and you can fly in higher winds as your skills improve.

Jack

jackerbes

You might want to try about 1/3 to 1/2 span ailerons. Less twitchy and easier to learn on. Most full ailerons are on stunt/3D type planes not trainers.

Would need a new wing but might be worth it.

Mike

Originally Posted by Hopalong X

jackerbes

You might want to try about 1/3 to 1/2 span ailerons. Less twitchy and easier to learn on. Most full ailerons are on stunt/3D type planes not trainers.

Would need a new wing but might be worth it.

Mike

Mike,

You might like to look at most .40 size trainers. They are all equipped with full span strip ailerons. These are the easiest to hook up as they require only one servo.

A simpler approach might be to make the ailerons narrower rather than shorter.

Ken

All,

This may seem simple to most folks here, but unknown to others. I have been a proponent to adding dowel rods to the LE and TE of UC BB wings early on. Since I had to do this for my Sea BB project, I thought you might like to see how this has been done. I have used this technique for all but the first 33" BB's with a UC wing, and the 24" UC with 1/8" dowel.



Some supplies and tools that I use are;

• Polyurethane glue
• Pencil or pen
• Tape measure or ruler
• Painters tape
• Small rat tail file (1/4")
• and 3/16" dowel (Poplar recommended)

I hope this is helpful and you enjoy as much as I have,
Ken

Edit: An altenative to steam is to simply soak the dowels in the bathtub for about an hour. I use hot water. This is the method of choice for now. Then you can just tape the dowel to the wing and let it dry, or as I do with elliptical wings, put on wet with the glue.

Note about wood choices: Obviously the harder the wood species gets the greater the likelihood of breaking it. Though the white woods look really nice, it is generally harder. I now always look for dowels made from Poplar wood, which is very easy to recognize by its greenish coloration. It is among the softer of the hardwoods.

Originally Posted by dz1sfb

All,

This may seem simple to most folks here, but unknown to others. I have been a proponent to adding dowel rods to the LE and TE of UC BB wings early on. Since I had to do this for my Sea BB project, I thought you might like to see how this has been done. I have used this technique for all but the first 33" BB's with a UC wing, and the 24" UC with 1/8" dowel.

Nice! I like the rat-tail file idea to cut a small hollow; means you need less glue, and probably get a better bond. If weight were a consideration, I might go with only partial-length rods, esp. on the trailing edge.

-John

Originally Posted by jfhspike

Nice! I like the rat-tail file idea to cut a small hollow; means you need less glue, and probably get a better bond. If weight were a consideration, I might go with only partial-length rods, esp. on the trailing edge.

-John

John,

That is exactly what I do for the 33" wing, and would probably do so fro this 42"er except this is for my Sea BB, and I will have wing tip floats. I wanted to be sure not to distort the wing with them.

Ken

Ken,
Excellent work! For those who have not seen your planes I will add the dowels provide clean durable leading and trailing edges that look good as well as add a lot of strength.

I like PU glue for all joints where strength is needed, and when possible I also put tape over the joints to minimize the foam out. It is a great way to join pieces into one panel, or join wing sections.

I have not been using steam formed dowels, but I will on the next build.

Don

Originally Posted by dz1sfb

Mike,

You might like to look at most .40 size trainers. They are all equipped with full span strip ailerons. These are the easiest to hook up as they require only one servo.

A simpler approach might be to make the ailerons narrower rather than shorter.

Ken

I agree they could be narrowed and a new wing not be built. After gaining some experience with them you could add the original size back to the wing.

I just wanted to provide a viable option.

Full size planes use approximately 2/3 aileron surface and 1/3 flaps.
Any 40 size or larger with flaps will also have similar proportions.

Mike

Just my two cents, but if your ailerons are too lively, simply reduce the throws to a comfortable amount. A lot of us tend to set our throws too high. Bob

My experience with the KFM3 wing on a 42" Blue Beagle and a 60 BBAP1 is that it is as stable a wing as I have ever seen. Neither plane has ailerons, nor do they need them. The Blue Beagle is basically a RET trainer for my wife (although we all enjoy flying it) and the BBAP1 is intended as an AP platform. It turns on a dime with rudder only, and doesn't need to do aileron rolls. What I need it to do is fly straight and level while I take pictures. This it does exceptionally well.

For me, it wasn't a matter of "needing" ailerons, but "wanting" them... as it makes a great aileron-trainer for those trying to learn.

Jack, I was looking at you BBIS. You know with an arrow shaft you don't even need the rear of the fuselage. You could just mount the fin and stab to the arrow shaft. Then you could get rid of the excess foam. Of course then it would be a BBSL (Blue Baby Slim Line).

Here is my BBM4 (Blue Beagle Mk 4) to illustrate the point. BTW, that's a KFM3 wing.

foamenator i'm going to be in las vegas in dec. do you know of any hobby shops & air field that might be interesting to visit?

thanks
gramps