From: egdorf@zaphod.lanl.gov (Skip Egdorf)
Newsgroups: rec.models.rc
Subject: Re: Some Glider Questions...
Date: 24 Aug 92 01:28:01 GMT
Organization: Los Alamos National Laboratory

In article <1992Aug20.164506.1723@Princeton.EDU> frei@astro.Princeton.EDU (Zsolt Frei) writes:

   After absorbing all the above information I still have some questions:

Here's my 2cents-worth...

   - Radio: If somebody *WANTS* to stay with polyhedral gliders do you
     still suggest to buy a 4 channel system, or a simple 2 channel AM
     system is enough? 

You will soon want spoilers at least. Also, don't count on staying
with polyhedrel forever ('though you may!) You may also be flying
along happy as a clam and get smitten with the aileron Sagitta-600
that the new guy just launched.

I suggest a minimum of a 4-channel system.

     How long will normal AA batteries last as transmitter and receiver 
     batteries in the cheap 2 channel AM systems?

See above. The nicads will serve you better in both the long and the short run.

   - Kit: Can I use STANDARD SERVO-s in the 2 meter planes???  

Standard: (.7" wide) Gentle Lady
mini: (.6" wide) Sagitta-600
micro: (.5" wide) ? Any 2-meter kits really need these?

     Wing loading is a key factor? Lower wing loading stays up longer?

Only in very light lift. In general, higher wing loading can stay up
as long, but flys faster all other things being equal (as they usually aren't).

     Are these planes good for both thermal and slope soaring?

The gentle lady type will start to flutter at high speeds. I generally
prefer to have more than one plane: a light floater and a heavier ship
for when the wind/lift kicks up. In general, the plane doesn't care
where the lift comes from. A gentle slope and a light thermal call for
a floater, and a strong wind on the slope, or strong thermals call for
ballested fast flight.

   - Hi-Start: There is very little talk about hi-starts in the FAQ file.
     Any instructions on how to use them? Which one to buy? 300 feet or
     800 feet versions? Can I operate it alone?

High starts are fine used alone. I launch with my left hand, and have
my Tx in my right for immediate control. Others at my field just
launch with the right and switch the Tx to the right after release.

The 300' and 800' designations are for total field required. The 300'
usually have about 30' of rubber and 90' of line. This stretches to a
total length of about 300'. The 800' usually has 100' of rubber and
300' of line.

I generally just buy the tubing and get my own kite chord and
home-made parachutes. The general rule of thumb is to have about 3
times the line as rubber. This is not critical. I have a standard high
start tubing (100' of the "heavy" tubing) with only 100' of line on it
for a tight field. It works ok, but I am being pulled down by the
weight of the line at the top of the launch. For my current field, it
beats cutting the tubing. I just clip on longer line for a full-size
field. I use this for both standard and 2-meter planes, though it is a
bit stout for a gentle lady.

The tubing will control the weight of pull. Standard high starts give
8-12 pounds pull, 2-meter tubing gives 4-6 pounds, and the small
"up-starts" give 3-4 pounds. The weight of pull is fairly constant
throughout a long range of tubing-stretch. The length of line just
allows the plane to climb with the tube not being lifted a lot. For
2-meter, just get one of the 2-meter sized high starts (not an
"up-start"). This will show you how they work and you can
roll-your-own when it is time to replace it.

   - Covering: Kits listed in the FAQ file do not contain any covering.
     What can I use to cover them? Monokote (and alike) is/are the only
     solution? Can I use Japanese paper with tightening lacquer?

You CAN, but don't. Use Monocote!

     How many rolls of Monokote are required for the 2 meter sailplanes?

1 or 2

     Do I need the heat gun, or the sealing iron is enough?

Just the iron for getting started (I still don't own a gun after 12 years
of flying.)

     How can I produce multi-color coverings frequently pictured in sales 
     catalogs? (Say half of the wing is blue, other half is white, not just 
     a simple trim sheet. See the Spirit in the Tower Hobbies catalog, page 16!)

Don't!!! An important lesson from a first plane is that planes crash.
You will learn that they are easy to repair (even in the field. Carry
along some CA, an X-Acto knife, and some black electricion's tape) and
that the normal dings are not to be worried about. Make a simple
covering for the first plane.  You will have an urge to make a fancy,
beautiful, contest-quality first kit and then be afraid to fly it
because you might scratch it. It is better to concentrate on getting
an aerodynamically sound, correctly-rigged, somewhat ugly first ship
so that you can concentrate on flying. Save the fancy color patterns
for the third or forth plane.

The one exception to this regards visibility. One of my favorite
planes was an Oly-II with left wing transparent red, right wing solid
white, and tail transparent blue. It was visible from a long way away
(you need to be able to see what direction it is flying toward or away
from you) and wasn't bad looking to boot.

Remember: There really is no such thing as lift.  The real trick is to
get a plane ugly enough that the Earth is repelled by it.

   - Misc: Besides kit, radio, hi-start, covering, iron, epoxy; what else
     do I need to get started? FAQ mentions '$60 for a 2 meter glider and
     other supplies'. What are those other supplies?

CA. One bottle of medium thick and a small bottle of thin. You will use
a lot more of this than epoxy on a wood kit.

X-Acto knife and a 15-pack of #11 blades.

A metal straight-edge. A metal yard-stick works well.

A box of pins. Normal sewing pins are ok. T-Pins are nice, but often
larger than you need.

A building board. Size it so that it will hold one sheet of your
unrolled planes.  Get a piece of 1/2" plywood and laminate on a piece
of white celotex with Elmer's glue and a lot of weight. A lot is said
about making this FLAT, but as long as it doesn't wiggle on whatever
desk or workbench you use, it is ok. You will be sticking a lot of pins
into it. Spread out the plans, cover with a sheet of waxpaper and
build your wing or whatever.

Sanding blocks: Make two. Use a 12" piece of 1x4 lumber, spray on some
Scotch 77 adhesive, and stick on a piece of sandpaper slightly larger
that the 1x4 is wide. Make one 100 grit and another 220 grit. Use
these a lot to fit parts, and clean up final construction.

Finally, AMA membership. You REALLY WANT the insurance. (There is SFA
as well, but I don't want to get the AMA-SFA flame war going again, so
let's keep it simple.)

				For What It's Worth
				Skip Egdorf
				hwe@lanl.gov
Newsgroups: rec.models.rc