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Old Jun 06, 2012, 11:09 AM
Is the sky the limit?
Joined May 2012
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What type of motor best suits ground effect?

Inrunner or out runner?
Or does it matter?
(for a lippisch specifically)
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Old Jun 06, 2012, 12:43 PM
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The main thing is the lower the thrust line the less pitch change with power changes. For a lower thrust line you want the smallest diameter prop that will work. For more thrust you can increase number of blades instead of diameter. RCPowers like 6x4 props, I guess that's a good start. At low speeds props are better than fans.

You can look back and see what worked in previous posts. Generally if prop is ahead of cg prop wash should blow downwards, behind upwards. The closer to cg the larger the angle. The ideal is generally not possible which is thrust line passes through vertical cg.

If you r building with foam build tail larger and cut down till you get close to what you want that works. Balance it to fly OGE but make sure the hull step is big enough to allow it to rotate for lift off or that the incidence is enough for take off.

What this forum has noted is they don't want to rotate probably because too much hull behind cg and when we put the cg back it will fly IGE but any little gust or PIO(over control) that causes it to increase height causes it to b very difficult and unpleasant to control.

Hope this helps.
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Old Jun 15, 2012, 03:09 AM
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Netherlands
Joined Sep 2006
374 Posts
Hey guy's,

It's been quite a while, but it's very cool to see that the thread is still running! I moved from the Netherlands(Europe) to Kenya(East Africa) in February, and I am currently flying on a Cessna T210 6seater throughout the country, to deliver precious goods for a Security Company. We bought the plane in March in the United Kingdom, and flew it down to Kenya ourselves, well.. I can tell you that that has been the most amazing trip ever! It took a total of 7 days to get there, having landed in England, Holland, Greece (twice due to some fuel problems), Egypt, Sudan and Kenya. All in all I am having the most amazing time.. Bushflying my way through the days.

Anyway, you can imagine that all this brought a rather abrupt stop to the Ekranoplan building.. Having left my unfinished Type C WIG and the huge Bixel in a corner of my garage. I found some other guys who do modelflying here, so I have been able to do quite a lot of aeromodelling over the last few months.. But finding a flat space for an Ekranoplan is difficult, as is the search for proper building materials..

I would say.. Keep up the good work, I hope to be able to continue my quest for a perfect WIG model this or next year.. But who knows. Anyway, amazing thanks for all you guys for the cooperation and idea sharing we have had in this topic since 2009, it's still by far the richest treasure chest of practical WIG aerodynamics and designs in the World.

Many thanks and best regards to all!

Marijn
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Old Jun 16, 2012, 02:08 PM
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Quote:
Originally Posted by nickchud View Post
How about this one..
http://youtu.be/bMQQ82YP_iY
or this one..
http://youtu.be/26JxpHKMJ00
or this..
http://youtu.be/R4_cU1CdqQs

I was searching for "pelicans in ground effect". It looks as if "surfing pelicans" would do it best.

good eh?

Well, there is more than GE at play here. Read this paper on albatross's flight . RC sailplanes use this technique to go 350 km/h - frightnening. Luc
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Old Jun 17, 2012, 04:52 AM
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wow just last night i was thinking about a glider that is stable in GE to mimic the energy saving technique of an albatross!!!!!!
i cant find the video i was looking for but if u notice the landing on this one it seems to skim for a while close to the ground which suggests it does not get nose heavy IGE. i think with more airspeed it would continue skimming for a lot longer. something like this might balance in GE hands off and make it easy for the IGE semi circle portion of the albatross soaring pattern.
flying wing glider (5 min 0 sec)
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Old Jun 17, 2012, 04:54 AM
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nice having you back marijn, was just saying this blog is going to slow without you. on which page is your aircat?
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Old Jun 17, 2012, 05:01 AM
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one of my observations of the bixel and aircat, the pontoon designs dont allow them to rotate easily which may increase ground roll dramatically. with such a long design i have had to much vertical area forward of Cg to give it enough incidence(AOA) to lift off easily. my next try will be shorter with more wingspan and a bigger hull step.
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Old Jun 26, 2012, 10:47 AM
Is the sky the limit?
Joined May 2012
10 Posts
WIG craft project

Finished it!
About to enter it into my schools science fair, unfortunately I haven't been able to test it, yet.
As you can see it is a lippisch similar to the airfish.
@captarmour, thanks for the advice, it helped
here it is, I hope it works
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Old Jun 26, 2012, 12:57 PM
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Looks nice. Where is your battery? Cg looks like it may be closer to 1/2 chord than 1/4 chord. If that's the case keep her close to the ground as she would not be happy OGE.

My guess though is if the motor is above the cockpit and batt as far forward as possible it could balance at 1/4 chord.
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Old Jun 26, 2012, 01:04 PM
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Also vertical side area ahead of cg promotes yaw instability which with 1/4 chord forward sweep will yaw instability would be compounded.
That being said the farther back are your winglets the better.
Your tail incidence looks to be less than wing incidence which is good for pitch stability. If it trims out with a lot of nose down elevator trim then ur cg needs to go forward untill ur elevator is close to inline. If anything err to a bit of 'nose up' elevator.
Happy flying
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Old Jun 27, 2012, 01:07 PM
Is the sky the limit?
Joined May 2012
10 Posts
The battery is a lipo- only 56 grams.
The craft is slightly imbalanced, even with the battery as far forward as possible.
having some problems with the radio =/ so testing will have to wait.

I know this is the wrong thread- but does any one know what would be wrong with a futaba 6exp with a 35.100mhz- channel 70(originally it had 35.200- channel 80) and a four channel single conversion receiver with the same frequency of crystal? cant find the answer anywhere, illl probably have to start a knew thread.
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Old Jun 27, 2012, 05:56 PM
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Can you move the motor forward?

Sorry cant help with the radio
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Old Jun 29, 2012, 01:40 AM
What could possibly go wrong?
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Joined Apr 2006
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Wig Craft Project

Very nice, Good Luck, I'm watching!


Nick
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Old Jul 11, 2012, 02:29 PM
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Nick when next are u flying ur Polaris?
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Old Jul 16, 2012, 04:18 AM
What could possibly go wrong?
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Market Harborough
Joined Apr 2006
3,696 Posts
Hello Dave

My various Polaris incarnations are presently on the battered plane shelf. Servos and motors have been borrowed for other projects. Presently a DH Vampire.

For exercising my dog, I've used another plane by the same genius who designed the Polaris. The VTO

VTO by Steve Shumate.MOV (4 min 37 sec)


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