Looking to build this in combo materials ..
I like both wet fuel and E powered ........... and this baby is a scaled up version of a UK classic ...
The original was based on the popular 40 sized glow ... and some people pushed them to 61's ... and obtained amazing antics out of them.
So now I am looking at mega sized ... over 70" span ... and that means mega power.
I know this is WATTflyer and E-Power based ... but bear with me ...
I want to take this plan (attached) and modify so that the model can take a big E-power system or a Gasoline set-up. To me - strength to carry such thrust is same ... (with gasoline we do have vibration as well ... but a suitable structure for any power is enough).
As you see in the plan - she's a conventional sticks and former job with partial sides ..
My idea is to create a central vertical spine in 4mm ply and then formers to create shape. The fuselage form then being foam sheet curved over and fastened. The fuselage to have PVA / matt laminated over. (4mm ply as that is the thinnest available locally !). Front nose section to be a box affair allowing large LiPo or Fuel tank.
Wing to be pine spars / LE / TE with foam ribs ....
Tail parts and ailerons to be foam and strengthened with resin or PVA / Matt.
My biggest problem is lack of materials available ... I have 4mm and thicker plys, 3 + 6mm Depron. Balsa is limited and hugely expensive. I have pine available down to 10mm thickness that I can strip to required.
So my build has to be from 4mm ply, 3 + 6mm Depron and 10mm pine.
So you see my idea .. how would you use such materials ?
Replacing balsa directly with pine (sometimes sanded a bit thinner) was common in WWII. Pine is in between balsa and spruce for weight but closer to balsa for strength.
The foam ribs should be fine. 3mm Depron will be stronger than a 1/16 soft balsa rib.
I don't see any major problems making it work out with your available materials.
My 53" biplane has replacement foam ribs in it after the smash vertically into tarmac ! So I know they work fine.
My main concern is the use of the 4mm ply which is not light-weight. It will mean plenty of lightening holes in it ..
I'm thinking that I might try creating two sides in it .. with plenty of lightening holes - it may just reduce the weight enough ...
Block foam to create the turtle-decks will be light as well.
I have a 4850 '60' Propdrive motor ... that came out of the 1680mm Cessna - so that should on 5S be enough .. it can run 6S so maybe doubled up 3S will be the deal. I have to admit though - my RCGF 15cc Gasoline motor keeps popping into mind !! I do apologise..
The model is quite a performer in it's original 52" size with a 40 - 50 motor in it ... Typical of the Chris Foss hangar ...
Even when you do find it - the sizes are just not there. I don't know where they get their ideas from but the balsa is just not sized for general aeromodelling.
I can strip wood also ... I have a bench saw that will cut up to about same ... worth it's weight in gold for spars etc.
Looks like a good design, I have a similar plane I had forgotten about until I saw your idea. Now I will have to get it down from the garage attic. Thanks for reminding me.
Years ago, a friend of ours, took his large commercial fishing boat to some place in Alaska. But he had too large a hold for the fish he would catch. They made him build a bulkhead inside it to reduce the size.
He built the bulkhead out of BALSA ! He gave some of it to us when he was done with that area. I have 4 x 6 and other sizes of balsa up to 72" long. It is not contest grade and there are some knots (hard as rock) but a lot of it is usable for many things. Maybe the spars for a plane like this.
Please send pictures as you build.
At present I'm stuck in Crimea ... but as soon as I get out of here and back home I have a few projects :
Tu144 for twin build contest
and of course this baby ....
Here's a picky of the original factory Chris Foss job it's based on attached...
Took a look at the plans you posted and am working on applying your available materials to these plans. Not much done yet, but will keep in touch....
Not quite sure whether I will go for ply sides and formers or a central spine ...
Whichever it is will have hole-saw lightening holes made anyway ...
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