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Old Oct 02, 2012, 01:37 AM
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andrecillo76's Avatar
Heidelberg
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Kent,

the 30° position is from tailed airplanes. It should work, but be careful. I would try first the 45° position and move backwards if possible. If the arm between the CG and hook is too long, the wing pitches strongly when releasing (like in your video) . This can have two downsides. First, the wing pitches so strong, that the hook might lose the rubber straight after releasing. Not good for the pilot, but great for spectators . Second, the wing pitches up so strongly without loosing the rubber, that the wing goes over to a stalled condition. You can imagine what this means: no control at all and the wing behaves like a kite on a string. Not good for the pilot and believe me, not good for spectators

Cheers,
Andrés
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Old Oct 02, 2012, 09:12 AM
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Thanks Andres. We are on the same page. I have personally experienced all of those scenarios with tailed planes. Just as you describe, a tow hook that is too far back can be disastrous in a variety of ways.

I'll start with the 45 degree position, which I consider to be very conservative. If the launch angle is too shallow, I'll pull back on the elevator while on launch. If I am able to do so without problem, then I'll add another towhook back further and repeat. When I get to the point where down elevator is needed on launch to recover from problems, then I'll know that I've found the limit. This is all based on dead air launches.

Kent
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Old Oct 03, 2012, 07:21 PM
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High Start Launch

­Tried the high start launch today with a single strand of rubber. Pulled it way back to the back of the sand dune. The line force was about half of that of the bungee. A long slow pull.
­
Worked well. Very stable with the tow hook at 345mm. No where near a pop-off.
­
­Kent

Manatee High Start at Beach (1 min 4 sec)
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Old Mar 09, 2013, 08:48 PM
KlonWarz
Joined Dec 2012
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Quote:
Originally Posted by Knoll53 View Post
After a 4 month build for the wood version, a quick foam version is beginning to look attractive. With it's segmented wing twist, it may not fly as well, but the difference may not be noticeable. A suggested panel layout is shown below.

Trust me, a 2m Manatee would be a big plane.

Kent
is there a planform posted somewhere that would show the rib forms which could be used to cut these wing sections from foam?

would be very nice!
tnk u
rc
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Old Mar 09, 2013, 08:51 PM
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Yes, posted somewhere in this thread Andres has a link to his website which has plans. This airfoil is 22% thick!!....Do you really want to fly that slow? It's kinda of a specialty glider.

Kent
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Old Mar 09, 2013, 09:41 PM
KlonWarz
Joined Dec 2012
455 Posts
[QUOTE=Knoll53;22870162]
The Masters at work

More Air Junkies

Yup, they're lookin' fer lunch!
Masters, nah... the condors excel at low energy soaring.
More than three flaps of the wing, it's NOT a condor! Well, except for takeoff from flatground... and a really juicy rabbit! lol
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Old Mar 09, 2013, 09:51 PM
KlonWarz
Joined Dec 2012
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Quote:
Originally Posted by andrecillo76 View Post
be careful, the airfoil you mentioned is a base airfoil and not the root airfoil! The airfoils at the root differ in thickness and camber. If you really want to re-cook the wing in Ranis, you'll have to export each rib from the DXF to a DAT file.
Aw gosh, can't someone just post a pdf file we could scale with adobe and print it out?
I can appreciate you fellows are hi-tech and enjoy the best tools, but I'd just like to build a wing!

tnx
rc
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Old Mar 10, 2013, 04:54 AM
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RC,

sure, I attached a PDF in a scale 1:20.

Andrés
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Old Mar 10, 2013, 08:31 AM
KlonWarz
Joined Dec 2012
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Thanks, Andres !

The simple pdf will be helpful.

I don't think I've had a real drafting program since autocad 2.5 and that was ages ago! lol
It seems all the limited capability programs available now all seem to come with software packages that seem to overwhelm my computers, so it's necessary to nuke them.
It is my intent to build in foam, so I need templates for a wire cutter.

Yes, Kent. A 22% slow airfoil would be dandy for me!
I have little interest in speed demons, which is good, since my vision and reaction time are waning. :-) I shall be self-taught, which is also high on the list of perils !

This Alpine Sled/Manatee/Horten is quite aesthetically pleasing to the eye and the videos taken at our Kalifornia Coast are wonderful... as are the videos from gebirge settings!

I hope to begin a mockup soon.
Thank you
rc
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Old Mar 10, 2013, 10:26 AM
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Quote:
Originally Posted by rusty case View Post
I hope to begin a mockup soon.
Thank you
rc
Feel free to post your build log here in this thread.
Kent
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