Conduit - my new UAV

[Tom Harper]

The Green 'Solution' finally bit the dust for good. It was an interesting experiment, but the 10:1 AR wing was definitely stall prone. Also, very fragile.

So, I sketched something new, but along the same lines. I thought about some profound names for the craft, but considering it's inspiration, it became Conduit. I built it around Photo 1 which shows all of the wire runs that support the camera and AttoPilot. For this model I wanted external access to everything, but with as few wires as possible hanging out of the airframe. So, I designed it around three layers of foam board. Each layer is separated from the next by a strong layer of paper. That way you can dig out the foam for wire runs (conduits), hence the design and the name.

Conduit is a pusher, profile model with an off the shelf foam core wing. The construction is 1/2" Foam Board for the fuselage, 3/16" Foam Board for the stab, fin and rudder. 3/16 balsa and 1/8" plywood here and there for the strong parts. The wing cores are covered with .012" thick paper Poster Board. The stuff is light, strong and cheap - $1.09 per sheet at the SuperMarket. Took 3 sheets.

This is an inexpensive, conservative model that is designed to accomodate a one pound camera and AttoPilot.

Wing: (McClain FBS 67 core $23) C = 11", B = 67", S = 5.12 sq ft, AR = 6:1

Fuselage: 1/2" Foam Board laminated - TM = 26", OAL = 47"

Stabilizer area = 25% of wing area

Motor: Heads Up RC - 3548-09 - 50 ounces of thrust - $32.95

Prop: 11" dia 5.5" Pitch

AUW: 111 ounces (3146 gr)

Wing Loading: 20.7 oz/ sq ft

[Tom Harper]

First flight was yesterday. A box on the camera mount carries enough lead to simulate a camera and two 4000mah Lipos (21 ounces). I only had 2100mah packs so it made two flights of about 5 minutes each.

[airmcn_3]

Looking very good Tom!

[CenTexFlyer]

Nicely done, Tom! Simple and to the point. Bet you get some good photo runs with it and the Atto in there.

Gene

[_helitron_]

Congrats Tom on your new camship, nice work at all !

Erwin

[Tom Harper]

Thanks guys!

The weather is holding steady so we should get in some longer flights on Thursday.

I ordered a bunch of 4000mah packs. Two of those should give me about 20 minutes flight time.

Tom

[Tom Harper]

Widened the battery compartment to accomodate multiple packs.

Will fly Thursday with two 2100mah packs for about 10 minutes air time. Nothing fancy, just circles for a while.


Tom

[Airboatflyingshp]

its an old trick but try a wing of blue or white foam but covered in brown wrapping paper stuck on with copydex or PVA as it drys it shrinks ..apply a coat of dilute Pva and a second layer possibly or let it dry then waterbased varnish. they use it on huge PSS foam slope soarers to great effect and the glossy side is perfect for paint, waterbased of course. No heat no melting less energy, theres also cardboard, not much energy saved but its biodegradable ..... ;) and combustable with less toxins :eek: ;) :D and free/recyled material.

Have you tried folded Foam board alone for the wing, with a simple foam board or wood spar inside? Im thinking Mud Duck uses a single 5mm foam board sheet Jedelski wings for their 108" span job.

Clive AKA the stainless steel Womble.

[Tom Harper]

I haven't tried brown wrapping paper. Will take a look at it.

The Poster Board resulted in a very strong wing. Brown paper might be lighter and I like the part where it shrinks.

GM silkspan and water based polyurethane might also do a nice job.

[Airboatflyingshp]

I like your ideas tom try this for more ways forward http://www.pssaonline.co.uk/ dig arround its got lots of layers. Somewhere I put up a link to help a guy with a cardboard flying wing this guys site http://home.earthlink.net/~charlesfelton/ but he joined in with his latest CL model........ :cool: :D :D As for how big/tough try this. ;)

[Airboatflyingshp]

One thing when brown paper shrinks you best have any structure firmly held down to see it being done on a trad sructure watch K Kusomas films in Waterplanes you will find a link in the free plans sticky!

[Tom Harper]

Fantastic models - Kuosma is quite a builder.

I'll experiment with brown paper and some water based acrylic on my latest venture.

[Airboatflyingshp]

use Pva glue diluted to sticK it and seal it at first, bathroom emulsion paints work for colour, build in your balsa LE stock and you can create U shaped section spars in your foam core by gluing in a stip of F.glass orr suitable woven fabric in it and then pushing the cut plug core back in leave it to set and sandflush with the wing suface. Lighter than full depth wood? If you want any articles - PM me a direct E mail so I can send it to you.

Glossy white paper is heavy as it contains Barities one of the heavy ist non metalic minerals it also blunts your scissors and kaolin, china clay. Foam board is heavy not because of the foam but the double layer of white Paper ;) Brown papper doesnt have the heavy stuff added and is more akin to a natural chopped matting. just remember glossy side out :)

[Airboatflyingshp]

http://findarticles.com/p/articles/mi_qa3819/is_199908/ai_n8871174/
http://www.rcgroups.com/forums/showthread.php?t=190499
http://www.emfso.org/electric_flight_articles_foam_models.asp

and http://modelairclub.ch.free.fr/?p=4-3-1&lang=en pictures a few results from a quicK search.