Real ultralight airplane - saucer-boat

[dtrip]

Hello people,

this is a really crazy idea, but I dont see any big problem
against it. For a cheap, reliable, slow-flying boat.

What we do is cross SeaAir's Flying boat (1st picture) and
the hoverdisc RC airplane (2nd picture), to get a real size
flying synthetic saucer. (3rd picture, I made with Photoshop,
sorry for bad quality).

NOTE: Of course it does NOT revolve like UFOs. It has a pusher
prop like the real flyboat, and a tail, like the Hoverdisc RC model.

A "saucer wing", especially with a thick airfoil, creates huge lift
and can fly slowly, therefore it will be rather safe to fly around
and more importantly land on water.

The problem I see is wether it could take off, since it would
need to run quite fast to lift from the water. But the
engine/propeller system should be low-geared, because this is
a slow flier. So there is a trade-off that might present
a problem.

Anyway Im not going to build it ! I just thought it an
interesting idea... what do you think ?

Dimitris

[Gary Warner]

this is a really crazy idea, but I dont see any big problem
against it.... what do you think ? Dimitris

Not :rolleyes:

Now flip the thing over and slide down a snow covered hill :p

Oops, my bad - no snow for a long time with global warming and all...

'And keep reaching for the stars'

(thanks for the laugh :D )

Gary
--

[dtrip]

Hmmm, Ive had some free time lately and always thinking
about crazy airplane designs (by the way did I tell you
about the RC TIE bomber ? the one from the Star Wars :eek: )

Anyway, in case anybody has FMS, I here is a related "saucer
slow flier", to make a better point.

EDIT: However I dont know if AS-6 existed for real, or even as a
model only.

[BMatthews]

I googled for the Arup series of very low aspect ratio wings and got a couple of interesting hits along with what I was looking for.

http://home.att.net/~dannysoar/Horton.htm
http://www.nurflugel.com/Nurflugel/n_o_d/weird_04.htm
http://www.theplanpage.com/Months/2503/arup.htm
http://www.century-of-flight.freeola.com/Aviation%20history/flying%20wings/early%20US%20flying%20wings.htm Check near the bottom

http://www.nasm.si.edu/research/aero/aircraft/pancake.htm

Enjoy.....

[Thomas B]

Hmmm, Ive had some free time lately and always thinking
about crazy airplane designs (by the way did I tell you
about the RC TIE bomber ? the one from the Star Wars :eek: )

Anyway, in case anybody has FMS, I here is a related "saucer
slow flier", to make a better point.

EDIT: However I dont know if AS-6 existed for real, or even as a
model only.

The AS-6 was actually built and flown, but was NOT a good flying full scale aircraft.

More details, here: http://www.luft46.com/misc/sackas6.html

[ghoti]

Where is the tail moment? They forgot it!
fish

[dtrip]

.....
http://www.century-of-flight.freeola.com/Aviation%20history/flying%20wings/early%20US%20flying%20wings.htm Check near the bottom
.....

Enjoy.....


Hello

Bruce, magnificent findings all of them !

in the above link Bruce sent , there is the following picture, which
is what I had in mind (although in a circle-shape, and a pusher prop
on top).

To get a wing load similar to the ultralight trikes (16.6 kg/m2) , the ship
must be about 5.4m in diameter for a TOW of 400 kg:
400 / (3.14*2.7*2.7) ~= 17.47 kg/m2,
[weight] / [wing area PI*R2] = [wing load]

which breaks down like this:
1. 100 kg for passenger (single seated)
2. 70+20=90kg for engine and fuel (engine assumed to produce 65 HP).
3. We got 210kg left to build the rest of the boat (no idea, is this
enough or what ?)

Dimitris

[BMatthews]

Prop above wing and hull below and a very small moment arm for elevator action means a very high forward pitching moment during the take off run. I'd be inclined to move things around a bit or at least put the prop in line with the elevator so the prop blast can provide some counter to the hull drag.

[dtrip]

Hello again everybody,

I am sorry for the delay, was busy with a new airplane I got
last week,

Bruce I understand what you mean, with the "forward torque".
Perhaps some downthrust will correct it ? Also, the boat will
have no hull, it will be flat underneath. This means that the sink
will be minimal, so the drag will not be much. (Of course it
also means that it will not sail very well in the water, but
what the heck, we are struggling to take off here ! :rolleyes: )

Anyway here are some sketches I made. The first shows
that the boat is flat, the sink is small, there is downthrust, that
the propeller is a pusher, and the tail fins are behind the propeller.
I think the prop should be pusher, for safety reasons, ie to be
as far away from the pilot as possible. The position of the horizontal
fin "guarantees" that if it speeds up, pulling the stick will provide
enough torque that the front will rise off the water.

The second sketch shows a 7m boat. The circles depict the 6m
diameter circle (WHITE) and the 5m diameter circle (RED). The
WHITE might be able to carry two persons (200kg) and the RED
100kg. (So at least one of the girls is not coming ! :( :D )

I also include the .psd (Photoshop) file of the 1st sketch, in case
somebody wants to move the parts around.

Take care all !

Dimitris

[BMatthews]

That's not going to work I suspect. A curved surface like your wing running in the water will actually suck itself down rather than trapping air and creating a cushion. Also floats and flying boats use the step located where it is to create a pivot point that they can use to allow the wing to be pitch controlled while still in contact with the water. Your long boat or saucer hull won't allow that and there's nothing to help lift the nose.

What I'd suggest is drop the saucer shape and look at the ground effect "airplanes" or GEM's to figure out a way that the wing can rest in the water but still trap air and form a ground effect "cushion" that lifts the model into the air. Once in the air you can then fly normally.

[dtrip]

Hmm... perhaps you are right... more likely to push itself down. :(

And now some more rambling :rolleyes: :

Oh well... I liked the saucer shape because its symmetric,
and kind of simple to produce (e.g. the boat hull could be
easily moulded in two pieces, I think ?).

Your suggestions made me find a similar successful approach:
GEMs (I Googled and located them as WIGS - Wing In Ground effect )
are beautiful and interesting. This is a great page:
http://www.se-technology.com/wig/index.php

(however those do not fly, just hover, well anyway they are cool)

Or, see the Robbe GEMINI rc waterplane (flies very well too!):
http://www.rcgroups.com/forums/showthread.php?t=539490

...but those designs would be really expensive to build for a real
size ultralight. The point was to have a really simple inexpensive and
reliable boat that can fly.

Well, now I am leaving this thread to die in peace :)

Take care all,
Dimitris

[BMatthews]

You're giving up too easily! You're right about the WIG. I thought they were GEM's but I didn't have much luck finding it with that acronym.

Anyhow try to imagine a WIG but with more wing area that CAN fly and only uses the WIG for the initial lift off. It's sort of been done alreasy with Laddie Musilasko's (sp?) NorthStar. This is a delta wing flying boat with a vestigal hull but that gets most of it's lift off force from the air trapped under the delta wing that initially floats leading edge high in the water.