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Author Topic: Wing size vs engine size  (Read 940 times)

Offline Target

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Wing size vs engine size
« on: December 03, 2017, 09:52:42 PM »
So, I have an Umland .15 sized Magician kit. It has a 235 square inch wing.

I also just got a .061 sized Magician kit elsewhere, and IT has 230 square inch wing.

I haven't looked at the differences in wing profile, fuse construction and such, but does anyone else besides me think I should add a bay to each wing half on the .15 sized plane and maybe make the tail a little bigger?

I will look more closely at the plans for each and report back on the construction differences if there are some I find.

Thanks,
Target
« Last Edit: December 29, 2017, 01:12:56 PM by Target »
Regards,
Chris
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Offline Target

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Re: Wing size vs engine size
« Reply #1 on: December 03, 2017, 10:13:05 PM »
So, after careful glancing of the two plans, this is what I have noticed-

Fuse construction for smaller model is lighter.
Wing construction for the smaller model is lighter as well.
Fuse in smaller model is shorter about 1", maybe a little more.
Wing profile in smaller model is thinner.
Nose moment is the same.
The stab sizes are identical, but the stab is moved closer to the wing on the smaller version (about the same distance the fuse is shortened).

So should I bother to make the wing a longer span on the .15 sized plane?
Seems like a lot more power to me there and more nose weight obviously with the bigger engine.

Thanks,
Target
Regards,
Chris
AMA 5956

Offline Paul Smith

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Re: Wing size vs engine size
« Reply #2 on: December 04, 2017, 08:01:18 AM »
Your question is tough because the power of 1/2A's and 15's varies all over the map.

With the kind of engines I use I would make a 15 stunter with 400 sqin and a 1/2A with 300 squares.

I built a Sig Acromaster 15 and stretched the wing AND enlarged the stab.  It flys OK, but nothing like a 40-size stunter.

Paul Smith

Offline phil c

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Re: Wing size vs engine size
« Reply #3 on: December 29, 2017, 10:15:17 AM »
An LA 15 will easily fly an F2D model on 52.25ft lines.  That's 410 or so squares. 235 is too small. An F2D wing is built much stronger than needed for a stunter, so 350-400 is right in the ballpark.  Lightening the wing makes up for adding a fuselage.

The original Magican was built pretty light, and the wing to tail was a bit on the short side, especially if you use the flaps.  It's much simpler no to.  So it sounds like the smaller plane is  a better rendition of the Magician.

Your best bet for changing the size of the plane is to take the  Magician plans to a local, small, quick-print shop.  They can scan the plans into a computer file and then print them to any size you want, keeping everything in proportion.

I still use an ancient Epson 510 dot matrix printer to "tile" print a working copy of plans and parts.
phil Cartier


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