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Old Aug 28, 2012, 01:02 AM
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Česká republika, Ústecký, Lipová
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Originally Posted by sfluck View Post
short question in between: did the a90 orlyonok have wheels for movement on concrete? I guess so!? Does anyone have a pic or something?
Hello.
I think yes. My Pictures aren´t good.
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Old Aug 28, 2012, 06:55 AM
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Winterthur ZH, Switzerland
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thanks for the pics! I stumbled over a pic just now:
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Old Aug 28, 2012, 01:27 PM
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Česká republika, Ústecký, Lipová
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Interesting!
Too bad, that my Orljonok is for this too small
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Old Aug 30, 2012, 12:52 PM
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http://www.youtube.com/watch?v=m4NYiI0otz8&feature=plcp

GE run hands off (0 min 15 sec)


hope you can see them.
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Old Sep 07, 2012, 07:30 PM
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Originally Posted by RdsG View Post
Yes, I tried. It doesn't like sharp turns :P When it banks in a bigger angle it loses its air cushion and touches the ground with one wingtip. But smaller angle banking isn't a problem.



Yes, plans would be great. However I couldn't built it soon. I don't have a foam cutter and I can't find bigger foam blocks :/ At the same time it would be a big help designing my further models since it would be the first plan of a RC WIG I have ever seen on the Internet (and elsewhere).

Gabriel

ps: I uploaded the last video to youtube because it loads faster.
http://www.youtube.com/watch?v=SU_XcpDBeSY

The best about this Lippisch desing is its efficiency. In the first "part" of the video the battery was empty (the ESC cut off setting was very low). GM2 Bixel always needed at least 70-80% thrust.
Gabriel

I know this is old but I sometimes go back and compare what we know now with what we knew before.

I was just wondering just as sailors say the 'length of the luff" is where all the performance comes from.

Could it be the wider wingspan is what made your Lippisch more efficient than your bixel?

Did they fly easily OGE? Or were they a 'handful'...difficult to fly?

My quest is a design that when trimmed for IGE, is 'nose heavy' OGE!

Rgds
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Old Sep 30, 2012, 04:57 PM
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It's a shame that our forum is dying...I guess that's life
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Old Sep 30, 2012, 05:01 PM
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Originally Posted by Pedrc View Post
Hello.
I think yes. My Pictures aren´t good.
Is it the shadow? Or are the LEs very sharp? I would think it would need nice fat round leading edges.
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Old Oct 01, 2012, 02:48 AM
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Ekranoplan ready for take-off

Hi all!

No captarmour, subject is not dying I'm watching it every day trying to find some answers for our project.

But today I'm very proud to show it to you. Our model is about 550mm wingspan (with tips) and weights 1140g.
The first test session was very interesting and showed that our two EDF were not correctly aligned with our CG and push too much downward. The result is that the Ekranoplan lifts its nose over the water but the tail drags a lot into the water. Videos were of very bad quality but I'll post some from the next session (hopefully tomorrow) I'm very excited with it as it took us about 2 months to design it and an other 5 months to build it.

Comments are very welcomed.
Cheers
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Old Oct 01, 2012, 03:49 AM
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Hello and congratulations.

It looks nice but, please dont take me wrong, Take in consideration changing the wing profile, it looks like a circle segment and, this is not the better way of providing lift.

Try to change the wing profile and use a simple and proved design such as the old "Clark Y".



The cg should be around 30-40% from the front of the wing.
Best regards,


Carlos

http://www.ovarcraft.com
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Old Oct 01, 2012, 03:53 AM
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Quote:
Take in consideration changing the wing profile, it looks like a circle segment and, this is not the better way of providing lift.

Try to change the wing profile and use a simple and proved design such as the old "Clark Y".
No worry camoesas, we've done a few simulations as well with that profile and it should bring us enough lift at pretty low airspeed with good GE. We'll make some more tests before building a second wing

Thanks for your comment
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Old Oct 02, 2012, 11:00 AM
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Originally Posted by captarmour View Post
Nice, what's this?
BWIG Box Wing In Ground (2 min 48 sec)
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Old Oct 02, 2012, 12:43 PM
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Winterthur ZH, Switzerland
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I am too looking in here every day and hoping for some news .

Has anyone ever tried the Gurney Flap on a ground effect model? That seems like a very handy easy modification that could help producing even more lift and achieving higher flying altitudes (opposed to that: additional drag).
Found a paper about it: http://soar.wichita.edu/dspace/bitst...pdf?sequence=1
CL is definitely higher with a gurney flap than without.

brgds
Stefan
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Old Oct 03, 2012, 02:45 AM
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First test sessions

Here we go! Finally we could run our first tests yesterday.

First run 02.10.12 (3 min 8 sec)


After that first run, we changed a little bit the angle of attack of the engines and the result is better.

Second run 02.10.12 (5 min 5 sec)


Now a few more improvements before we'll put full throttle:
  • Move the CG a little more backward
  • Seal the middle cover. We finished with 5mm water inside the fuselage...
  • Raise a little bit the engines to avoid water to go through
  • Make a bigger elevator as at low speed it's not efficient at all

Now one issue you guys might help us with: Do you think our fuselage is too much "stuck" on the water, especially in the back? Should we make bigger cut-off to help the air to release the water under it?

Thanks
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Old Oct 03, 2012, 04:52 AM
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On page 26 some tips on hull design by hoverman.

Remember at less than about 20% chord height above 'ground' the wing produces very little lift. Any lift is from 'ram' effect. That being the case if you remove some of the LE droop you will get more air flowing under the wing and may increase lift for take off.

IMHO every flying machine needs to be balanced to fly. We all know that our model planes are barely controllable with cg aft of 30% Mac. If we can somehow design the WIG to work balanced as an aircraft we will be very happy. Look at pg 24.

Longtitudinal stability requires that the forward wing has more incidence so as to achieve a higher aoa than the following wing.

Keep up the hard work, you have a gr8 model!
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Old Oct 03, 2012, 05:01 AM
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Would be nice to get some feedback on the videos in post 1069.

The model actually gets nose heavy OGE, therefore more stable.
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