On Sat, 25 Jan 2020 08:00:32 -0700, Dan Marotta wrote:

Wow!Â* Imagine what would happen if the rubber band was over wound...
And another occurrence of fly-by-wire(less) control. :-D

Yes, doesn't bear thinking about!

It turns out it was only 90 pounds of best quality 1/4" aero strip as
used to power competition models - an unstretched length of 17,500 feet,
5350m, 3.5 miles. It was made up into a 400 strand motor 25 feet (7.7m)
long and expected to take 700-800 turns when fully wound. The airframe
weighed 220 lbs without the rubber.

Here's the most complete version of the story that I've found, complete
with a picture of the Rubber Bandit rigged ready to fly:

http://sustainableskies.org/a-chance-to-unwind/

.... but it doesn't say why the Rubber Bandit never flew. Elsewhere I
found an estimate that the 90lb rubber band cost $US 180,000 and hinted
that this had a bearing on it not flying. But that can't be right,
because even at today's prices that 90 lb motor would only cost $US 3500,
and the article didn't say they needed a new rubber band before they
could go and fly.

BTW, this wasn't the first rubber powered manned aeroplane: in around
1988 an EAA chapter built and flew the first one. They modified a Lazair
ultralite by installing a vastly extended centre boom containing a more
modestly sized bundle of aero strip and with a big prop on the front.
This only had 23 lbs of rubber in it, but did manage to fly 1000 ft:

http://www.lightsportaircraftpilot.com/
rubberband_powered_ultralightaircraft/index.html

Maybe its my model flying background, but I think the Rubber Bandit looks
a lot more elegant than the RB-1.


--
Martin | martin at
Gregorie | gregorie dot org