A Battery wing?

[quorneng]

To obtain maximum aerodynamic efficiency for endurance flying I considered putting the batteries (and everything else) in the wing.
As 'building in' a LiPo is not recommended, I purchased some A123 (LiFe) cells from E-bay.
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These 1000mAh cells are not tagged so I was faced with adding them to build up a 4 cell (12V) flight pack or was I?
One my Depron wings used a substantial balsa/depron/balsa box spar so could 4 cells simply be inserted into the spar as a 'battery box' spar? My first thoughts.
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A 4 cell 'battery box' spar
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A 12" centre section 'battery' spar with the batteries along side .
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The intention is that everything is contained within the flight surfaces.

[Brianathayes]

I wouldn't think that spreading the weight of the heaviest item out along the wings was a good idea. Think of the inertia - surely aileron response would be sluggish to start and slow to stop, or reverse?

[QuackingPlums]

Introducing some latency in the aileron response might actually be beneficial for certain conditions - aerial photography for instance. This would also be a situation where extended flight times would be of use too.

[quorneng]

As this concept was a test for endurance flying (big battery, minimum weight) a slow aileron response was not really a concern but spreading the load does allow a light wing to safely lift a heavy battery weight and it also eliminates most of the fuselage weight & drag.

In this application the 4 cells will be heavier than all the rest of the plane put together.

Where a high wing inertia might be an issue is in a spin. It could make the recovery uncomfortably slow!

[David]

All up weight would be identical irrespective where the load is on the aircraft once airborne, accidental latency as a by-product = "bad design" if it can be avoided, especially as you can dial it in anyway far more accurately from the transmitter. In addition it will surely add significant stress to the wing on landing.

Reduce the drag on the fuz as in aerodynamic drag or do you mean load? unless your going to hang the batteries outside the fuz, I dont get that one at all.

If you intend to build a conventional fuz, which by the nature of its structure double's as a cargo hold for batteries anyway, have you now added unnecessary weight in the beefed up wing structure, which doesnt look that light to me.

I really dont see any benefit in this design that couldn't be achieved with a conventional build, unless you have an absolute reason, for example, all of the space in the fuz is occupied with other kit or something like that!

Alternative design "Maybe" and I am all for that. Not sure about "Better" though.

Probably need more info to understand.

[Richard]

Its a stick model, there is no fuselage! In such a model we normally keep the gear close as possible to the centre.

The only issue I see what has been mentioned about landing, having the weight of the batteries at the wing tips will strain the wing spar especially on a bumpy landing.

I'm sure we could build a spar box strong enough to stop the batteries being ejected, give it a go and see what happens. Its worth the experiment now

[1958steveflying]

I should think if the wing were to stall it would be very violent, and recovery height would be several times more than needed if the weight were more central. personally I would have doubled up the batteries in the middle at least eliminating the 2 extreme batteries.

[giskard]

Those cells are fairly heavy, I'm not sure how much support the depron is giving the balsa, it doesn't "feel" like the unsupported box would be strong enough to survive much sudden acceleration (or deceleration). I'm with keeping the weight as close to the centre of gravity as possible.

[David]

Ok .. No FUZ... is a big bit of information to leave out! Irrespective that there is a picture with a stick hanging out of it (which did not confuse me at all, even though I might have said "What the FUxx is that for")

In that case Great design

Seriously that out bound weight could be a big problem as others have mentioned.

[Mudlark]

I'd stick two 2s packs(thin as possible) under the wing. 2 each side and close to the stick fuz. Do them on velcro so on a hard landing them should pull off. Thenprobably hit the only pointy stone and burst into flames