Wingtip shape matter much?

[JamesD]

I am modifying a downloaded Sopwith Pup plan. I am going for lighter/slower. I am throwing out the scale look, for weight saving.

The wings and elevator have an angled back plan, with the training edge shorter than leading edge. To ease building, I am thinking of making the tips straight.

The question is: will changing the tips in this way noticeably affect flight characteristics?

Thanks,

James

[Andy W]

probably, but whether it would be better, or worse, I doubt anyone could predict! :)
..a

[Sparky Paul]

No. Indetectable.

[Andy W]

Don't trust anything you read here unless you can verify it with another, independant source! :)

[Martin Hunter]

Is it this pup:

?

[Flyfan]

I've just flown my SE5A wings made from 3mm foam, I copied the tips because they, most of all, identify the era of the aircraft.

I don't think at this size and speed it will make any measureable difference.

More important is the cross wires between struts. It made an enormous difference to my foam wings, added 500% stiffness I reckon.

Rob

[JamesD]

[QUOTE]Originally posted by Dreamer
[B]Is it this pup:

Dreamer-yes that's the one. Though mine will not look as nice as yours, for I am stripping it down for lightest possible....

What gear do you have in yours?

How slow can it fly?

What do you think about the shape of the tips?

I may have second thoughts about modifying the tips, they are so pretty in the original plan.

Any way I can get away without rigging? I would love to get wings off easily.

James

[Martin Hunter]

James,

Mine flies the same speed as my GWS Moth... slow and easy. I'm not sure how much benefit lightening the plane further would be unless you're determined to fly it indoors. I fly mine with a GWS DX-A, 300 mah NiMH 7 cell, 3x HS55's, and JR 610 receiver. I'm not sure what modifying the tips would do to the flight characteristics, however I'd be unsure that will save weight at all... if it does, it would only be a matter of fractions of a gram, I'd think. The pup flies beautifully with or without rigging. The way I designed the mods, she can be fully rigged and you can still quickly and easily remove the bottom wing. I hope all that helps! Feel free to ask questions as you have them

[Al P]

Dreamer:

Beautiful Pup ! :)

Al

[JamesD]

Dreamer,

The tip mod was just for convenience in building, not to save weight.

The plan called for a 280 motor, but I wanted to use the DX-A, so I thought I should trim some weight.

Is yours 30 inch wingspan?

Thanks,

James

Originally posted by Dreamer
James,

Mine flies the same speed as my GWS Moth... slow and easy. I'm not sure how much benefit lightening the plane further would be unless you're determined to fly it indoors. I fly mine with a GWS DX-A, 300 mah NiMH 7 cell, 3x HS55's, and JR 610 receiver. I'm not sure what modifying the tips would do to the flight characteristics, however I'd be unsure that will save weight at all... if it does, it would only be a matter of fractions of a gram, I'd think. The pup flies beautifully with or without rigging. The way I designed the mods, she can be fully rigged and you can still quickly and easily remove the bottom wing. I hope all that helps! Feel free to ask questions as you have them

[Martin Hunter]

Ohhhhh! I get it... email me at percival@telus.net and I'll send you an updated plan. With Jim's permission, I modified the plan to include the DX-A and various other details. Do a search for pup in the parkflyers section and you'll see various construction and in flight photos of mine.