Thursday, August 03, 2006

What Do You Call A Boomerang That Doesn't Come Back? A Motor Mount For a CAP232!

I know, I know . . . . . no one in the blogosphere gives a rat's ass about my airplane even one simple little iota. Well I do damn it and it's my blog. Add that to the fact that I have absolutely nothing else to write about right now and you start to see why you're all about to be treated to yet another post featuring graphic descriptions of a busted assed miniature flying machine.

Even Orville and Wilbur had to start somewhere.

So here's the deal. The stick mount idea didn't start out so good. After sawing off most of the remains of the factory plywood motor mount, I attached the aluminum stick mount adaptor that came with my motor and started test fitting the whole contraption on the front of the plane to see how it was going to line up. At first everything looked like it was coming together nicely . . . . .

Until I tried to test fit the cowl.

The motor ended up sitting about a half inch lower than it was supposed to. Were I to reuse my battered cowl, deleted aperture and all, It might fly like that, but it looks like ass. Nope, not gonna do.

So I was once again off to see my good friends at Abell Hobby. I really should start charging these guys for advertising, maybe I could get a little of my money back anyway. After picking out the rest of the parts I needed (replacement for busted up engine cowl, replacement for bent prop hub that was determined by the FAA's post incident forensic analysis to be the actual cause of the entire disaster) and hashing out the pros and cons of various different motor mounting options involving a whole lot of cutting and drilling and filing and fitting on the part of Justin the would be aviator, John suggested an offset plastic stick mount from E-Flite that seemed to be just what the doctor ordered. After a test fit this evening I'm happy to say that said doctor knows just what to order, it fits perfectly and appears to be a good bit stronger than the old mount, without adding much if any weight. Now it's just a matter of final fitting everything together, applying a little epoxy in the appropriate places, and trimming my new cowl to fit hopefully without screwing up. In the name of light weight the molded parts of this plane are made out of a single layer of micro thin fiberglass with another layer of micro thin gelcoat applied to it for that magnificent, glossy, Turtle Wax shine. It looks great, and is reasonably durable, just a wee bit fragile if you don't handle it carefully.

The stuff is about as easy to work with as an eggshell.

Ever tried to cut an eggshell without cracking it?

Anyway, here it is with the new mount test fitted together awaiting final fitting. As you can see if you ignore the blurr and the perspective induced optical illusion of misalignment, the new mount moved the motor right back up to where it should be, but it attaches to the opposite end of the motor. As a result the motor should get a lot better airflow for cooling, but I'll have to reverse the motor shaft. I didn't happen to have an Allen wrench to fit the set screws in the house and the shaft has to be pressed gently to avoid breaking the bearings, so the final assembly will require a trip to the shop to complete the necessary modifications to the powerplant extraordinaire. It's a long walk, and I'm tired (lazy), so it'll just have to wait until morning.

If the morning happens to demonstrate an absence of severe zephyrian displacement, I may just grab a different plane and head to the field and it may have to wait a little longer. Ownership of multiple Lilliputian sized aircraft has its benefits, if I ever figure out what those benefits are I'll be sure to share that information. None of my other planes can match the CAP's performance however, so I shall not rest until it's once again certifiably airworthy, hopefully for an extended period this time.

Zooming around with the Sky Fly is alright, shooting touch and goes with the Coroplast disaster is far better than being at work, but nothing quite replaces the thrill of flying the CAP. Ease on a little throttle to taxi out to the runway, get on centerline, feed in power as I muscle the rudder to counteract the torque of that little blue power house in the nose and watch her gain speed until the tail comes up, then ease back on the stick to break the bonds of gravity and lose the drag from the wheels so the airspeed can build up just a little higher.

Then, as soon as all is right with the world, point it straight up and nail the throttle until she almost disappears from view, chop the power and lay the rudder full over for a graceful stall turn. As soon as the prop is where the tail was a second ago, corner the sticks for a death defying spin back to a dangerously low altitude. Add power, apply some elevator to level off, then toss it through a couple snap rolls (did I double check to make sure the battery was tied down solid?) before making a few passes over the runway as low as I dare, maybe inverted, maybe knife edge, maybe right side up at half throttle with a little opposite aileron and rudder thrown in for nice sideways crab like the big boys do at the airshows to give the crowd a good look at their planes.

Level the wings, firewall the throttle, ease back on the stick and concentrate on the rudder inputs necessary to fly a nice, round loop, easing off the power on the back side and coming out of it right where I went in just like the pros do. Then make a fast, high pass to the other end of the field just for an excuse to pull it straight up again, crank it through half of a vertical roll, then lay on the elevator to swing the tail up and around so she's flaming back toward mother earth at breakneck speed, pulling her back level as close as possible to the point where the whole thing started, a little trick called a Humpty Bump that's really just a creative way to turn around.

Make a bunch more passes, throwing in a roll or two on each one just to keep things interesting, maybe fly a few circuits of the field inverted, or maybe just fly around slowly enjoying how realistic she looks with nothing in the sky for perspective until the juice from the battery starts to fall off. Throttle back for the downwind, execute a 180 degree procedure turn allowing some speed and altitude to bleed off for the approach, roll the wings back level hopefully lined up with the runway. Ease back a little more on the throttle, crab her sideways a little to bleed off the last of the excess speed, add a tiny bit of elevator to set up a nice, controlled descent being sure to clear all obstacles, don't stall her now or things get ugly.

Then just at the right moment, feed in just a hair more elevator, not too much, and watch as she settles onto the asphalt, hopefully as gentle as a feather. Taxi back to my feet and let my heart slow back down before I pull out the battery and turn off my transmitter. Is another battery done charging yet?

Yeah, you might say that I enjoy flying it.

Picture compliments of Matt Chapman Airshows.


Ken Hayes said...

As a kid in Bridger I put several plastic model planes together and hung them in my bed room. When I got tired of them I would take them out and suspend them from a tree and shoot them down with a gun. Was great fun at the time. I was a real ace and now wonder why I did it. I guess there wasn't much to do in Bridger and I hear there still isn't unless you go to Jim Bridger Days. Sounds like you have a good time. Ever put a machine gun on the planes and see what you can do?

Justin said...

A bunch of us were laughing a while back wondering if we could toss together some simple, durable planes out of foam or coroplast, then charge people to shoot at them with paintball guns as we fly by. One of the guys said they had run into some kids that had showed interest in such an activity, LOL.

I've never seen one with a machine gun, but I have been entertaining the idea of one of those Airsoft guns that shoot the little plastic BB's. You'd need a fairly large plane to lift one, but it would definitely be cool. Bomb drops are fairly common, although I've never gotten around to building one myself, and I did see a video somewhere on the web where a guy had rigged up a GWS A10 Warthog to fire missiles. He made an ignitor system that fit in the wing nacelles along with some metal launch tubes inside to keep from melting the foam wings. He used those little crayon shaped plastic rockets out of those Saturn Missile fireworks for the actual missiles. It looked pretty cool, two little smoke trails zipping out ahead of the plane with a whistle and a pop. I'll have to see if I can find the video again and put up a link.

Anything except dropping bombs that merely use baby powder or flour to simulate an explosion, or anything that fires any kind of projectile, is strictly forbidden by AMA (Acacemy of Model Aeronautics) rules. It's not like the Gestapo is going to come knocking on your door or anything if you do it, but AMA members get liability insurance as part of their membership. If an accident happens, and the AMA determines that you weren't following any of the rules when it did, your insurance won't cover it. It'd really suck to drill a plane into the side of somebody's car, and then find out that your insurance isn't any good because you had an Airsoft gun rigged up in the nose. Could get a little spendy.