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Old Apr 26, 2005, 06:23 PM
Will work for foam
wingnutt's Avatar
United States, WI, Muskego
Joined Apr 2005
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Swept TE DLG wing?

Greetings all! First post for me and my I say this is a wonderful forum. On to my question...

all of the DLG wings i have come across (ie Boomer EX2, etc.) have straight or swept forward trailing edges. is there a disadvantage to a rearward swept TE other than wing-joint stress? it seems you could get a more efficient wing with rearward sweep (less washout or twist).

just curious.

thx,
wingnutt
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Old Apr 26, 2005, 06:34 PM
Striving to Rip the Bring
raptor22's Avatar
San Diego, socal, USA, North America, Earth, Solar System, the Orion arm, Milky way, Universe
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Swept wings tend to have lower glide ratios, and straight flying wings usually use not twist at all. instead, they use a self stabilizing airfoil. But that is not the main reason.

The biggest reason si that it is very difficult to produce a swept dlg wing that has enough tail to not roll while yawed while still keeping the cg even close to the right spot.

Beleive me, I've tried it. The plane ended up carrying half its weight in lead before I could get the tail far enough back to make it launch right.

--Alex
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Old Apr 26, 2005, 06:35 PM
Striving to Rip the Bring
raptor22's Avatar
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Oh, and welcome to rcgroups!
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Old Apr 26, 2005, 06:51 PM
Will work for foam
wingnutt's Avatar
United States, WI, Muskego
Joined Apr 2005
1,502 Posts
raptor22,

that is a good point. figured as much, but wanted to bouce it off the group. glad i asked before committing the foam and time.

you mentioned that the straight TE ships do not use twist with the right airfoil. I have been looking at the EMX-07 for a 'Boomer-ish' type dlg. i plugged my values into the panknin twist formula and its suggesting 4 deg washout. should i for-go the twist, or build it with the washout?

thx,
wingnutt
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Old Apr 26, 2005, 07:15 PM
Striving to Rip the Bring
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Skip the twist. You may add a degree for stall charicteristics, but as far as performance is concerned you'd be best without it.

--Alex
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Old Apr 26, 2005, 07:54 PM
Will work for foam
wingnutt's Avatar
United States, WI, Muskego
Joined Apr 2005
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Will do!!

Thx
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Old Apr 27, 2005, 12:04 AM
Striving to Rip the Bring
raptor22's Avatar
San Diego, socal, USA, North America, Earth, Solar System, the Orion arm, Milky way, Universe
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Keep us posted on the dlg! Sounds like it should be cool.

What size will it be?
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