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-   -   Oly II V tail (http://www.Wattflyer.com/forums/showthread.php?t=72758)

FishHawk 12-09-2013 12:59 PM

Oly II V tail
 
Has anyone tried adding a V tail to the Oly II instead of the conventional tail?
FishHawk

fhhuber 12-09-2013 02:11 PM

Not me personally, but seen it and it works... if done right.

Basic rule for conversion to V tail:

Increase area 20% to 25% vs flat horizontal stab and set at 110 to 120 deg V.
The larger the vertical was compared to the horizontal, the larger the % increase and steeper the V.

If the V is not steep enough you lose yaw stability. If the % increase is not enough you lose pitch stability. If the shadow of the V is the same as the original you'll be fine for pitch effect. Its not as simple on the yaw.

Too big and too steep (you can do a 90 deg V) works but can get very draggy when applying the elevator.

Abuelo 12-09-2013 03:12 PM

Quote:

Originally Posted by FishHawk (Post 933699)
Has anyone tried adding a V tail to the Oly II instead of the conventional tail?
FishHawk

In the dim, dark ages of the 1970s there was a method published that supposedly would always work. Might give you a starting point.

Locate the center of the stab and then raise each tip by 35 keeping the same 'look down' length. This will give you the same stab area and incidentally a workable fin/rudder height. The attached diagram shows what I'm talking about, the dotted vertical line is the theoretical fin and rudder.

Abuelo 12-09-2013 03:14 PM

1 Attachment(s)
Here's the photo, didn't attach the first time.

Bill

fhhuber 12-09-2013 05:32 PM

No such thing as an "always works" when changing the tailplane from conventional to V...

Rudder/fin proportion to the horizontal varies too much.

DEG 12-09-2013 06:39 PM

Not to start a riff here but I don't think he said "always works"....."method published that supposedly would always work." is much closer. And that comes very close to what was previously quoted. A great starting point.....cheers folks...:)

Abuelo 12-09-2013 06:43 PM

Quote:

Originally Posted by DEG (Post 933727)
Not to start a riff here but I don't think he said "always works"....."method published that supposedly would always work." is much closer. And that comes very close to what was previously quoted. A great starting point.....cheers folks...:)

Thank you.

Leadchucker 12-10-2013 03:43 AM

You might want to look at this too:
http://www.charlesriverrc.org/articl...tailsizing.htm

kyleservicetech 12-10-2013 03:53 AM

Quote:

Originally Posted by FishHawk (Post 933699)
Has anyone tried adding a V tail to the Oly II instead of the conventional tail?
FishHawk

Seems to me, if my fading memory is correct, a "V" tail sailplane is no more efficient than the standard tail section on these sailplanes. A V tail does provide a lot more safety in landing though.

FishHawk 12-10-2013 12:42 PM

Thanks guys
 
Thank you all for your input. I just might try it!
Something about a V tail makes the model look cool to use an old expression!
FishHawk


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