Need Help!!! Great Planes Cap 21 Giant Scale (88" wingspan)
 

I'm looking for someone that built / flown / has experience with this Cap 21. Although my main reason for getting this Cap 21 is because I really liked the plane in the 80's, I thought I might use it in Basic or Sportsman to start with for IMAC. I've never flown a Cap or Extra type plane and don't have any real building experience with this kind of kit. Price was right, plane was right, so here we go...I do fly pattern currently and have about 25 years (on and off) of flying experience with sport models of various kinds over the years, but this is a different plane to fly if I'm not mistaken...

The kit has a Fiberglass Fuse, cowl, wheel pants, and a -one piece- balsa sheeted foam core wing (not started yet, still just foam cores). It also has "steel" landing gear (bet they weigh a pound by themselves...LOL), I will be going with CF Gear...LOL Try to save weight were I can...

Is it possible to make it a two piece wing without sacrificing strength?

I have thought about having all new cores cut for use with CF tubes for the wing and stabs. Possibly changing the rudder profile to more of todays Cap 232 look. Have no idea how it will change performance (if good or bad...) or if by changing the rudder will I no longer be able to fly it in IMAC Sportsman / Intermediate due to the Scale rules?

Is a DA 50 too much for this plane?

For a 21 year old kit, the foam, fuse, hardware, and wood seem good as new. However, I wonder if aged foam is weaker?

Any thoughts or helpful building tips out there?

Thanks in advance for those that wish to reply...

LD

PS...I have talked to Paul Clements, who I believe kitted this plane for Great Planes in the 80's. He did say it was a good solid plane and snapped better than any he had flown. However, it was a lead-sled built per plans and the CG on the planes is were it was happiest.

RE: Need Help!!! Great Planes Cap 21 Giant Scale (88" wingspan)
 

You can make it a 2-piece wing. I was going to do the same exact thing with a Lanier Giant Stinger kit. Not planning on buiding the kit for awhile--so it's on hold. But, it can be done. Just costs money.

I contacted one of the foam wing cutters, and asked him if he'd take my cores and cut socket holes in them so that I could install a phenolic and an aluminum tube. He said it was no problem as long as I had the cores and construction on the wings had not been started yet. About $35 + shipping both ways.

What you do is install the phenolics and put a piece of lite ply at the bottom of the socket to keep the tube from digging into the foam when the wing is assembled. Drill a hole in the back of the wings and install a brass tube and use a 5/16" dowel about 3" or 4" long for an alignment pin.

Put a dowel in the LE of each panel and a hole in the back of each wing for a mounting bolt.

You now have a 2-piece wing. It still attaches to the fuse with dowels in the front and bolts in the back--your just using a tube for the center section and a dowel in the root, at the rear for alignment purposes. Take the bolts out and pull the wing off the fuse. Slide the wings apart and go home. When you want to fly--just slide them together and bolt it in the fuse.

Crude MS Paint image attached:

RE: Need Help!!! Great Planes Cap 21 Giant Scale (88" wingspan)
 

As long as you stick to the 10% rule you're fine.

I had a flying buddy who had one of these - it definitely was heavy, but it flew precision aerobatics well. I believe he had a SuperTigre 2300 in it, don't think a DA50 would be a good choice for your ship - but you can certainly try! I seem to recall it had relatively small control surfaces compared to the newer designs.

As long as the Sportsman/Intermediate forms don't have too many vertical lines and you watch your downline speed, you should do fine in the classes you mentioned.

DB

RE: Need Help!!! Great Planes Cap 21 Giant Scale (88" wingspan)
 

RCPilet,

Thanks, that picture helps a bunch...Do you have contact info for getting new cores cut?

LD

RE: Need Help!!! Great Planes Cap 21 Giant Scale (88" wingspan)
 

DB,

Any idea how much your flying buddy's Cap weighed?

Thanks for your reply,

LD

RE: Need Help!!! Great Planes Cap 21 Giant Scale (88" wingspan)
 

I think I contacted Bob www.flyingfoam.com

RE: Need Help!!! Great Planes Cap 21 Giant Scale (88" wingspan)
 

I wouldn't trust my memory - but about 16+lbs. All I know for sure is that it weighed more than my 15lbs 120 size Ulti. The fellow with the Cap21 is (was?) MHawker. You could try to PM him for the info and he can give you first hand info on the plane (if he still has it).

Good luck!

DB

RE: Need Help!!! Great Planes Cap 21 Giant Scale (88" wingspan)
 

the imac 10% rule has always been meaningless, since i am not aware of any event that had the resources or the need for it to be properly enforced. but assuming that it is a valid consideration, your next problem is finding the full scale documentation on a cap 21. but perhaps the best idea is to convert into something else - like a 231/EX...take a wing planform from an Extra 300S and design it for the Cap. It will fly much better and no one will know the difference.

Bob Mellen is a local, and a very good guy.

P

RE: Need Help!!! Great Planes Cap 21 Giant Scale (88" wingspan)
 

Agreed

If the 10% rule actually was applied--99% of our airframes wouldn't qualify.

Extra 330L--never made by the factory. Doesn't qualify. Thousands of them flying IMAC. Good luck finding factory specs and documentation on that plane.

I have a World Models 90" Extra 330L in a box. I'm not putting the 330L stickers on it. It's a 300L if I ever saw one.