Pulled this baby down off the wall today and plugged it together real
quick for some pictures. I thought it might inject a little insperation
into your next flying adventure. ;)

Here's what I call a "clown plane". CAP-21 model that I purchased
several years ago from an elderly gentleman getting out of the hobby.
When I got it, it was about 80% completed, no engine, no radio, needed
quite a bit of hardware.

Pictures:
ftp://delberts.audizar.com/delberts.stash/FLYING/cap21-1.jpg ftp://delberts.audizar.com/delberts.stash/FLYING/cap21-2.jpg ftp://delberts.audizar.com/delberts.stash/FLYING/cap21-3.jpg ftp://delberts.audizar.com/delberts.stash/FLYING/cap21-4.jpg ftp://delberts.audizar.com/delberts.stash/FLYING/cap21-5.jpg

I going to guess that's it's a basement operation kit from the mid 80's. Conceived at a time when fiberglass over foam construction was popular
for doing larger, rounder, models. It looks like either 2 part urethane
foam, cast or machined into a shape, then covered with fiberglass,
filled, sanded, etc., like a Long-ezy. OR perhaps 2 part urethane cast
into a molded fiberglass part that is still in the mold, then pulled
out as one integral piece... not sure.

What is for sure is that this type of foam sandwich, or foam filled
contruction makes for a tough bird, with the tradeoff being that it can
get a bit heavy compared to some of the other model construction
methods.

Wingspan: 92 in.
Wing Area: 1150 sq.in.
Weight: 27 lbs.
Wing Loading: .376 oz/sq.in. or 3.38 lbs/sq.ft.
Engine: Twin Super Tartan - Glow - on Tuned Pipes.
Prop: Zinger 18-10

The Twin Tartan turns the Zinger to about 8400rpm static, and about
9000rpm in the wind tunnel (big leaf blower), running on 90% methanol
10% castor. Pulls about 25 pounds static thrust, so it won't quite hang
on the prop, but full throttle tail slides should be pretty damn
realistic looking.

Control surfaces all use one jumbo servo each (each half of the
elevator), with ball ends and 4-40 hardware. Pull-pull cable for the
rudder. Counterweighted ailerons... you get the idea.

Spar carry-through is 1.00 x .065 T-6 aluminum tubing. Slide on wings,
etc.

I am making no attempt to make this thing look beautiful. It's a clown.
It's the only plane I'd let spoonge-bob fly. ;)

It could be ready for flight in about an evening at this point, but I've
never flown it! The local big-bird club I was a member of lost it's
field about the time this thing was ready. The other places I fly from
time to time won't handle this size and speed of airplane.

I'm pretty sure if it does fly, it will be something of a lawn dart,
with a long flat approach to landing, high stall speed, and probably a
fairly abrupt stall. Judging from the wing loading, symetrical airfoil,
and tapered planeform, I will need to "blow the rust out" with something
a little tamer for a couple days before I try this one out. ;)

Angus, have you looked at any of the various fiberglass contruction
birds out there? (flying surf boards we used to call them) Might be a
good choice for a durable daily flyer type of an airplane. Or maybe just something to take out and dust off and fly after you've just stoved
in one of your nicer stick built jobs.

-j-



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Re: Big CAP-21 Will It Fly?
By: Delbert to Angus Mcleod on Tue Sep 25 2007 19:13:00

Here's what I call a "clown plane".

hey, at least it isn't an Extra! ;-)

What is for sure is that this type of foam sandwich, or foam filled contruction makes for a tough bird, with the tradeoff being that it can
get a bit heavy compared to some of the other model construction
methods.

Yes, foam is heavier than built-up. But this

http://tinyurl.com/3yal3o

is the result of a mid-air argument between built-up and wire-cut foam, Obeche-sheeted and glassed. The other wing was undamaged, but it does
take an 80-sized 4-stroke to push that 40-sized model around!

Engine: Twin Super Tartan - Glow - on Tuned Pipes.

That should be nice.

The Twin Tartan turns the Zinger to about 8400rpm static, and about
9000rpm in the wind tunnel (big leaf blower), running on 90% methanol
10% castor.

Only 10% castor? I don't like to go much under 17% even with a 4-stroke. What is your usual ambient temp?

I'm pretty sure if it does fly, it will be something of a lawn dart,
with a long flat approach to landing, high stall speed, and probably a fairly abrupt stall. Judging from the wing loading, symetrical airfoil,
and tapered planeform, I will need to "blow the rust out" with something
a little tamer for a couple days before I try this one out. ;)

Doesn't have to be. I've seen some pretty hot aircraft that had very
docile low-speed performance envelopes. 'Course, I don't known the CAP-21 personally....

Angus, have you looked at any of the various fiberglass contruction
birds out there? (flying surf boards we used to call them) Might be a
good choice for a durable daily flyer type of an airplane. Or maybe just something to take out and dust off and fly after you've just stoved
in one of your nicer stick built jobs.

To tell you the truth, I dislike glass-fuselaged kits. I like wood construction. Glass models make me think that soon I'll be flying some
sort of injection-molding or something! Ugh!

OTOH, a model like my GWS Tiggie *is* an injection-molding!

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Playing: "Deep Honey" by "Goldfrapp" from the "Black Cherry" album.
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Re: Big CAP-21 Will It Fly?
By: Angus McLeod to Delbert on Tue Sep 25 2007 22:47:00

Yes, foam is heavier than built-up. But this

http://tinyurl.com/3yal3o

is the result of a mid-air argument between built-up and wire-cut foam, Obeche-sheeted and glassed. The other wing was undamaged, but it does
take an 80-sized 4-stroke to push that 40-sized model around!

I like the way they fly with a little heavier wing loading. More
realistic, both in piloting and appearence.

The Twin Tartan turns the Zinger to about 8400rpm static, and about 9000rpm in the wind tunnel (big leaf blower), running on 90% methanol
10% castor.

Only 10% castor? I don't like to go much under 17% even with a 4-stroke. What is your usual ambient temp?

The factory recommendation is 8%. I run 10% just to be on the safe
side, what with the pipes and all. Tartan is a different beast. Takes a
little while to understand what they like and don't like, but nicely
made engines. Very Italian. Never use Nitro with one.

Doesn't have to be. I've seen some pretty hot aircraft that had very
docile low-speed performance envelopes. 'Course, I don't known the CAP-21 personally....

Well, I don't know THIS one personally, yet, but I have a feeling...

To tell you the truth, I dislike glass-fuselaged kits. I like wood construction. Glass models make me think that soon I'll be flying some
sort of injection-molding or something! Ugh!

OTOH, a model like my GWS Tiggie *is* an injection-molding!

They serve the purpose of being durable, and they lend
themselves to scale shapes that would otherwise be difficult or
impractical done in wood.

BTW, that particular Twin Tartan came off of an ACE Kermit Week's
Special that I crashed a year or two before I bought the CAP. I wish ACE
would have kept doing what they were doing. That Weeks, and their other
big kit were all great flyers, and good kits to build.

-j-



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