Monday, November 27, 2006

AV - The Little Wheel in Back

Real airplane, the fan is in the front, the little wheel is in the back. That is, if it has a little wheel. Started out, we just had a skid. Nowadays, lotsa folks frown on skids. But if you're into Flying On The Cheap there's a lot to be said for a skid.

The main purpose of putting anything in the back is to keep the tail off the ground. If that's all you want to do, you use whatever works. Skid works.

Most folks incorporate some form of energy absorption mechanism in whatever works; that thing that keeps the tail from hitting the ground. Piecea wood works. Pivot the piecea wood in the middle, wrap some shock cord forward of the pivot, when the thing hits the ground it won't break. Kinda springy. Sorta like a spring, which also works. Leaf spring, like one offen a car. Or a wagon, if it's a small wagon. Fiberglas works too. Or you can use a piecea wood. Ash works good. Hickory too. (Ask for a sledge hammer handle. In a pinch, you can use a shovel handle. In fact, a popular homebuilt from the 1930's used the curved portion of a shovel handle for a tail skid.)

The bad thing about using a steel spring in back is the sparks. Looks kinda neat, taxi'ing at night, little shower of sparks behind you. Not on grass, of course but over at Palomar or Oceanside. More fun at Palomar because they got a tower and you know how much folks love sparks when they live in towers.

Or you can use a piecea wood, put a little metal shoe on the end. Best of both worlds: Cheap, easy to make piecea wood, with a couple wraps of shock cord. (You can get some at Home Dee Pot.) Plus, you got this steel shoe, gives you a nice shower of sparks when the tail comes down, causes Tower Dwellers to shine their red light at you and say funny stuff on the radio. Almost as much fun as landing on the taxi way. (I have a lot of trouble remembering my hull number, usually just add five to the last one I heard. Seems to work okay.)

Have you seen them white plastic cutting boards? I've been using them for fair-leads. Slippery stuff.

I'll bet you could put a piece of white plastic cutting board on your tail skid, cause it to stop sparking and start sliding. Not very handy at Ranchita, though. In fact, that's why you have a steel shoe back there, so's you can come to a stop before you hit the windmill. No, you can't go there, it ain't a runway, it's a road. Graded it nice & smooth after the Pines fire took care of the brush. Seven hundred foot of road. Only folks that use it is me and a lot of dope smugglers. That metal shoe works a treat on dirt. Not too many sparks. But some. Guess I'd better put on a wheel.

Little wheel. Harbor Freight. It thought it was a caster until I got aholt of it. Sez ‘88x31' molded into the rubber. Or urethane. Or whatever. Ball bearing. Three-eights bore. Made up a tail-wheelie-thingee outta some tubing, couple of bronze bushings. Zerk fitting. Horn bolts on. Don't weigh much but it's heavier than a piecea wood and three feet of shock cord. Hell of a moment, too. Seventeen feet four and three-quarters inches times four point three seven pounds, plus the spring... means I have to move the whole gawdamned engine forward about 1.375 inches just so's I can have a little wheel in back. Or bolt about ten pounds of lead to the oil cooler. (Rather move the engine.) Now I gotta find some sort of spring.

Looked around for a steel spring but couldn't find one I could afford. Checked with the EAA experts and was told I could find leaf springs in any junk yard. One EAA expert told me to look for a Model T, take the spring offa that. ( When was the last time you saw a Model T in a junk yard? Where do they get those people?) These are the same experts who think the Spruce Goose is made outta spruce and that an AN3 is 3/16". I guess they don't get out much.

Ever heard of a camber compensator for swing-axle Volkswagens? It's a steel spring shaped about like an archers' bow except with angles instead of curves. Bolts to a pivot on the bottom of the tranny with the ends of the spring out toward the wheels, pressing up on the axles. Works. Sorta. First used it on the Porsche, way back When. Spring is about an inch and an eighth for bugs, inch and a half for buses. New, they want the earth for the thang but used, at the swap meet, over where all the air-cooled Volkswagen owners get together, you pick one up for a twenty dollar bill.

One camber compensator makes two tail wheel springs. Pretty good tail wheel spring, too, cept it's kinda soft. And at twenny bucks, expensive for someone Flying On The Cheap. (Yes, I got a couple of them. But you don't. And the Flying On The Cheap thingee is really for you, not me.)

Harbor Freight, that's the ticket. Go prowling around. They leave you alone in Harbor Freight. Go to Home Dee Pot there's always some idiot asking if they can help you. So you ask, "Double headed nails?" and they give you a silly smirk as if you've just dropped in to practice your humor. Real hardware store carries crockery and dynamite and knows what you mean when you ask for five pounds of eight-penny double headed nails. Home Dee Pot only seems to have these perky idiots offering help they can't provide.

So I go prowling around Harbor Freight and find the Perfect Tail Wheel Spring. Looks like a pry bar but it's really a tail wheel spring. Or soon will be.

Yes, I made some drawings. They'll eventually go up with the other ' stuff. And I'll take some pictures too, soon as Santa comes around (I've been saving up for a digital camera.) Then I'll have me a regular tail wheel, like all the yuppies use.

But I'm gonna miss them sparks. And blowing the tail around. And getting the Tower Dwellers all excited. Mebbe I'll send them over to Home Dee Pot, tell them to ask for redwood plaster lath. Regular snipe hunt, seeing all them yuppie-type clerks running around trying to figger out what Redwood Plaster Lath might be and if they got some and where it might be hidden if they do. Wasn't like that at the old hardware store. "Gimme ten sticks of twenty percent Hercules, twenty caps and five foot of fuse, please." And they'd write it up and ask you was there anything else. Shoulda stocked up on wooden plaster lath when I had the chance.

-Sept 2003

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