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Wednesday, May 21, 2008

The Electricty is back on.

With the spate of power failures lately , it means I have to carefully schedule my vacumn bagging between (load shedding) but this is different this is load lifting.. a kind of ....when the wind dies inhouse thermal generater, insurance.
I am moving into new territory here so anyone using any ideas, seen here do so at your own risk......sign here..............
Time to build a power pod with a serious brushless motor which by all accounts can probably
allow ground take offs, with a decent runway and a dolly with biggish diameter wheels, something we will definately attempt.

A piece of offcut bluefoam sanded into a streamlined shape and cut vertically.Then a piece of plywood was added onto which the foam was glued , this is because the foam will be removed later. Some carbon tows added to the leading edge and some layers of 163gr glass.

The actual model is waxed and masked and the power pod base layed up on it for a perfect fit.

This has to be strong so it is about 10 layers of 163gr glass and 1 layer 200gr carbon.

Note the pod sits above the wing joiner also the centre of gravity.

Motor housing was made by waxing a
cooldrink plastic bottle((or whatever size the motor needs) and wrapping around first some cloth then 2 x layers of UD carbon off cuts and some final layers on the outside , next is some more sanding required to smooth it all.

A plywood insert was made using the bolt hole template supplied with the electric motor.

The three bigger holes are airvents.

It is epoxied and glassed in place. Next is some more .............sanding.

.Next the foam was melted out with thinners and it was sprayed with a 2k white, which made it look rather like it belonged on this white glider...exactly right.
In this view you can see, the air can flow through and cool the interior of the motor , there is also a space aroud it and the back is open, all to assist cooling.
For reasons that soon became apparent it has to be a pusher ,if I use the folding prop, a fixed prop will work on the front I have both so have various experiments to try.
I am not starting with Lipo's... seen to many pictures of planes on fire. So until the technology
starts making sense I will run this motor with several ganged 5 cell ni-cad packs of 4800 mah, this motor has a spec of 16 to 22 cells and about 380 revs per volt (prop dependant)so the magic instruction booklet says.
It only needs to run short bursts to gain height for futher gliding or to start a safe landing approach.

The recently maidened and flown Ventus was built light especially for this reason and will be used as this power pod test bed, no fancy pop up system , just common sense engineering.

If this all proves successful , outlanding off more outrageous slopes will no longer be a problem.
Progress so far, next its wiring it up and some motor test runs
then its off to find some BIG AIR and do some tests.
Ps the blog showed 22222 hits when I logged in, that must be a good omen


John said...

It's a sad day when even Mike turns to the Dark Side and uses an Electric Motor in his glider.

mike may said...

Dear John,
Sad day indeed but sadder still when others are flying the marginal lift and my big birds remain grounded. This dabbling in the dark arts has a bigger motive which should become apparent in future posts....How long exactly is Jomacs runway?

Glen said...

Get a Weasel or an Alula hehehe!!

bruce said...

Looks fantastic, reminds me of baby bee pods on my early chuckers. Earlier experiments with nicad packs and gliders resulted in a lost Spectra (range) due to the ESc not leaving enuff juice for the servos. (got the bird back 9 months later intact) Be sure to have a decent esc with a cutoff at x voltage to the motor to avoid this.