Nf-ID: #R:arizona.edu:3529:trsvax:5000011:000:5057
Nf-From: trsvax.tandy.com!earl    Jul 24 14:25:00 1992



/* ---------- "Indoor R/C" ---------- */
Does anybody have experience flying indoor R/C? I'm curious about what wing
loadings would be reasonable for flying in a 55 x 25 meter (180 x 82 ft)
gym.
In one reference I've seen, they recommend an upper limit of 0.122 g/cm^2
(4 oz/ft^2) for wing loading. An IMS indoor contest in 1980 had an upper
limit of 0.0915 g/cm^2 (3 oz/ft^2).
Those limits seem a bit low to me. For the larger wing loading, a 30 degree
bank and coefficient of lift of 1.0 that gives you a turn radius of only 4
meters. Airspeed is 4.8 meters/sec. I would think you could get away with a
larger turn radius, although it's hard to say without actually trying it, I
guess.
Is that reasonable? Or is my coefficient of lift to optimistic? Any
comments?
I've tried to use a Microsoft flight simulator to get a feel for the
problem, but I haven't had much luck setting up the simulator properly.
Reference:  Poling, Mitch. _Building and Flying Electric Powered Model
Aircraft_, 1984, page 73.
-- Frank Manning                                -- "For every vision
-- College of Engineering and Mines             -- there's an equal and
-- Civil Engineering 100, University of Arizona -- opposite revision."
-- Tucson, AZ  85721    frank@evax2.arizona.edu --             -Unknown
*******************************************************************

   A long time ago, when CANNON first came out with their Micro radios, several
of us tried indoor RC pylon racing. Basically we used scaled down Quickie 500
(Quicky 160's?) models, built up out of balsa and covered with whatever was left
as scrap covereing materials. At first we ran 200 sq in wing spans, but we wound
up down to 150-160 sq. inches as competition got more heated. We all ran COX
TeeDee 010 engines. Even then these little suckers could really go fast, after
they got going (not much oomph on the hand launches).

   We were lucky, in the fact, that we had access to a couple of large hangers
for aircraft, that weren't in use at the time. At first we ran into a lot of
radio interference problems, due to the metal hangers causing a lot of
RFI reflections inside. We wound up just cutting off the excess receiver
antenna wire (reducing range, obviously), and collapsing the transmitter's
antenna enough to still give good control inside the hangers. Unfortunately,
the aircraft hangers we used are much more roomier than a school basketball
gym. But we had a lot of fun back then. At that time we though about building
up some 50-60 inch glider type models and running Cox TD 010's to see if we
could fly much more slowly, but nothing came of it. Because the models were
so small, their relative strength to wieght ratios were good, thus they'd
withstand midairs, crashing into the cieling, walls, etc, without any damage.

   Tower Hobbies has started offereing a Lanier RB-1 Condor rubber motor powered
glider (74 inch span with a 16" prop), that is all foam injection molded. This
would make a cheap, easily setup model to try out indoors. It has about 500 sq
inches of wing area, and weighs in at about 28 ounces, add a Cannon super micro
radio which can weigh about 1.5 ounces for 2 channels, and you'd have 29.5
ounces all up which gives you about 8.5 ounces per square foot wing loading. 
Being a foam model, it would be fairly rugged for withstanding encounters with
the walls and ceiling. Being rubber powered would be clean, and avoid messy
fuel mess clean ups.

   One of the RC modeling magazines, very recently had a couple of pictures of
a indoor RC model, built up using lots of carbon fiber. It looks to have almost
nothing for wing loading. Unknown what they were using for radio control.

    I have given thought to building up a hand launch glider (eg. Dynaflite's
Skeeter) wing, and makeing a stick fuse and putting my Cannon radio into it
along with a big prop for rubber power, and trying it out too. But I've been too
caught up with other things to sit down a fabricate a nice rubber motor prop.
The new Cannon super-micro radio flight packs are down to about 1.5
ounces for battery, receiver, two servos, and a switch harness. This would allow
one to build a really light airframe, if your careful and use some carbon fiber
tape too. The rubber band motor props are the hardest to make in this case.
For models like these you pretty much have to make your own propellors, as
no one sells them anymore.

    I don't know if it helps, but it did jog my memory and remind me of some of
neat, wild and crazy fun things I've done in the past.



***********************************************************************


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						Earl W. Bollinger
						@ <trsvax!earl>


"You were in the Clone Wars!", said Luke excitedly.
"Yes", replied Obi Wan, "I was a DOS programmer. But that was before the dark
 times, before OS2."



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