From: enrique_at_perez.tc
Date: 04/30/00
From: enrique_at_perez.tc Date: 1 May 2000 02:50:22 -0000 Message-ID: <20000501025022.15029.qmail@www.nameplanet.com> Subject: Re: Current airship project
Hello,
> Patrick Salsbury <salsbury_at_sculptors.com> wrote:
> Sounds very interesting! A picture would better help me visualize it,
>but I think I have the basic idea pretty well.
>
> Are you sealing and inflating the whole body, or just putting gas
>bladders inside of a static frame?
Thanks for the interest, I've attached a crude sketch. The sketch is for the
next model 4 m I'm making, the 1.5 m model has only one ring stabilizer without
a ducted propeller, the purpose of this model is only to determine how it
glides.
The whole body is sealed at the edges and inflated with air. The edge is sealed
with two sided 3M scotch tape Cat. 136 NA 34-8501-2152-5 12 mm wide bought at a
supermarket. It gives a weak tack; but, since the polyethylene is overlapped
with the tape between, the tape only has to take shear forces and not also
peeling away forces, so it forms a bond as strong as the 4 mil polyethylene. To
lift the airship, a round bladder like a large mylar party balloon would be
used, about 2 / 3 filled with helium at sea level and taped to the top center of
the airship.
The next model I'm hoping to make is to be 4 m on a side with a wingspan of 4 m
* sqrt( 2 ) = 5.6 m. It'll be made of two translucent tarps bonded together at
the factory; since two squares bonded at the edges is a simple and fairly common
request, the tarp company can make this for little extra cost over the cost of
both tarps. I hope to fly this and use it as a personal boat. With my weight in
the boat, it won't be able to fly; but, at least I'll be able to motor on
English Bay. To control it, I'll use an RC model controller to change the power
outputs of each electric ducted propeller and drive it like a tank. Since the
thrust of the fans is directed downward and they are at the back, hopefully it
should point up and rise when power is applied and glide down when the power is
off.
The cardboard triangles would be replaced with half inch thick blue styrofoam
with fiber tape on the bottom, so it can bend upwards without breaking. The
inflator fan will remain at the top so it won't suck up debris and will stay dry
even when the airship is used as a boat. The inflator fan on this model is a
tiny Radio Shack one inch computer fan, for the larger model, I'll use the
largest computer fan I can find, probably a 5 inch version.
I'll send an update after I throw the blimp off a hill next week.
Cheers,
Enrique
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