From: svoboda@rtsg.mot.com (David Svoboda)
Subject: Re: Skis & Cold weather running
Organization: Motorola Inc., Cellular Infrastructure Group
Date: Mon, 23 Nov 1992 06:21:17 GMT

In article <1992Nov19.172736.13186@tin.monsanto.com> lesnyd@monsanto.com (Larry E. Snyder) writes:
|In article <Bxz0qF.CGA@acsu.buffalo.edu>, v064myby@ubvmsb.cc.buffalo.edu (Christophe J Quaranta) writes:
|> 
|> 
|> 	As I live in cold & snowy western New York, I'm wondering if I could
|> put skis on my pt40 trainer & fly it off of snow?
|> 	Has anyone tried this? 
|> 	Also what's the best way to keep the engine running in cold (10-20 
|> degree) weather? I've heard various solutions involving hose clamps around
|> the cylinder, adding gasoline to the fuel, etc.  
|> 	Any help would be greatly appreciated.
|> 				
|> 							Latre,
|> 							'Q'
|
|Model Aviation (I think) had an article several years ago about making your
|own skis for your RC plane. It was complete with plans and everything. Since
|it only snows here once or twice a year it wasn't worth it. If you can find
|an archive ov MA, try that.

Well, I didn't notice the MA article, but I have made many sets of skis from
children's plastic snow toys.  Go to a sports store, or even a toy store, and
look for some sort of snow-skis, or plastic sled, and try to visualize cutting
away appropriate bits of plastic to come up with appropriately-sized skis.

I have one in my hand at the moment that would work for a 40-sized trainer.
It's about nine inches long, three inches wide, has several nice strakes
down the length to give good directional control, and is made of a really
tough nylon-like plastic (you can bend it double, and it pops back) about
1/16" thick.  And it's an absolutely sickening color of teal. :-)

You can just take a block of hardwood with a 5/32 inch hole through it and
screw it to the ski, with the heads of the screws coming out the bottom
of the ski.  That doesn't seem to cause too much drag, but if you worried
about it, you could counter-sink flathead screws if you wanted.

Then you just bolt the skis on the landing gears with regular wheel collars.
Make them loose enough that they flop loosely.  The block should be just 
far enough forward that the trailing edge of the ski drops when released.
You keep the ski positioned by running a peice of carpet thread from a
convenient spot on the fuse (like gear hold-down screws) to a small hole
in the far back edge of the ski.  Make the string so that the TE of the
ski hangs down a bit while in level flight, and make both skis identical.

If your plane has a nosewheel, just do it just the same way.  The strakes
on the skis will give you directional control.

If you have a tailwheel, you could make a small ski for it, or just leave
the wheel there, and have no ground steering.  (Don't expect to taxi a
whole lot on snow, anyway.)

As far as running the engine in the cold, it just isn't much of a problem
until you get below zero, except for starting.  For starting, as small
shot of lighter fluid (naptha) in the carb does wonders, and use an
electric starter.

For REAL cold weather, you can use an additional "igniter" in the fuel
to keep things burning.  Something like "propelene-oxide" I think, but 
that may be wrong.  Net?  

I don't think I would restrict the cooling of the engine.  Just expect
the engine to cool off at low throttle settings, so don't expect great
throttle response, or a reliable idle.

The biggest problem with winter flying is your hands.  It isn't too
good flying with heavy gloves on, but frozen fingers don't fly too well,
either.  The best solution I have used was light gloves, and a plastic
bag around the entire transmitter, with a hole for the antenna, and
rubber bands around the wrists.  You have to have someone pit for you,
though.

And dress REALLY warmly.  You are standing motionless in cold weather.
You can get colder than you realize.

(My winter experience comes from growing up flying RC all year around in
Iowa.  The club I was with had a yearly "earlybird" award for the first
person to fly on January 1 of each year.  The field rules didn't allow 
engines to start until 8:00am, so if the weather was nice, there would be 
five or six bundled-up flyers poised ready to start their engines.  A couple
of years my father and I won by default by being the only ones to be out 
flying in -15F weather, even if we didn't get going quite at 8:00am.  It got
so cold once that the glow-clip wire shattered.)

			Dave Svoboda, Palatine, IL