Elastic Bands; Wing retention.

[wingcoax]

Just measured up the wings on an old? Mascot trainer.  10" chord wing used 7" white bands x6. Never had wings come loose in normal service. ps found a bag of bands recently that have to be 20 years old, still as they were bought.

[J D 8]

 PatMc. I have found it does more so on glider types flown where the landing site can be rough. Catch a wingtip on a tuft or something and there is a lot of leverage at the bolt fixing. I find 4 bands enough on these lightweight [less than 5lb] models that are not flown in an aggressive manner, wing will twist out of square with fuselage enough to save damage most of the time.

Edited January 22, 2022 by J D 8
more info.

[dave windymiller]

Something worth noting is the way the bands are put on.  The last example has no side force keeping the band (green) on the dowel (red) and relies on tension and dowel length only. Add a bit of slippery fuel residue and they can fly off too easily along with the wing. 

 

 

Edited January 22, 2022 by dave windymiller

[ken anderson.]

last century when i was "learning" with my dear Yamamoto....the rubber bands save my model a good few times from getting wrecked......and more time repairing than flying..

 

ken anderson...ne..1.........L dept.

[David Mackay 1]

I have experienced all the above observations so why no use springs. Springs will "give" and return to position. They will not deteriorate and available in many sizes. Ensure the load is not on a single point to evenly distribute the load on the balsa and use hard  wood. Another thing that deteriorates with ultra violet light is fibre glass resin. So keep that in the dark as well.

[J D 8]

   Springs will "give" and return to position. Hmm, I recon that is what the bands do.

[Rich Griff]

More metalwork flying around etc..

[Dad_flyer]

On 20/01/2022 at 09:47, EarlyBird said:

For 12" between the sticks I use 8". 

Flying two models with bands today. 12" chord Ugly Stik, 8" bands. Then the same 8" bands on Double Diamond which is about 15" chord and then the sticks are nearly 4" below the wing. Because 8" are the biggest I have and DD is tough.

[Robin Colbourne]

Diagonally crossed bands are less likely to come off in a cartwheel, so are more likely to result in damage to the leading and trailing edges.  Parallel bands do come off so protect the model better.
Diagonal bands put their load on the thickest part of the chord at the dihedral beak, whereas straight ones do so outboard of the fuselage side, so they support the wing better too.
If you are concerned about the bands sliding off before you want them to, then your dowels should be longer.

[Don Fry]

Or a small thin band across the wing, span wise, to hold them on without stressing anything in the event of an arrival.