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Jul 27, 2010, 11:43 PM
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hoverman's Avatar
Originally Posted by derk View Post
although i must admit the cg is FAR rear from your models
Haha now that is a good thing right I am no guru, also just playing around. Remember, my models have a AoA difference between the fore and aft wing of about 3 degrees, which is huge, resulting in a faaar forward CG. Actually, even with a more rearward CG they still glided well, only up to a certain speed(then it would flip). I shoved the CG all the way up front and increased the AoA difference, to see if I could make it stable in & out of GE, with other words to stop it from flipping at higher speeds

Anyway, cool that it works, ow, and just saw your video, seems very stable!

Jul 27, 2010, 11:57 PM
derk's Avatar
i think i am going to add wheels to it for takeoff, then it may not need the help at the start.

i think my need for the rear cg, is that the ratio of lift between my front and rear wings is larger than on your models. different setups for different builds i guess
Jul 28, 2010, 02:23 AM
derk's Avatar
well, its all buttoned up, wheels added also. i did a flight earlier that ended in a hard stall, so i moved the battery to the rear of the nose compartment. i think the wheel pants may have had something to do with the stall, but i'm not sure. more tests tomorrow when its light out and maybe a video from the outside.

i think the weight now is right up to 5 ounces which i think is still respectable for its size.
Jul 28, 2010, 05:02 AM
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hoverman's Avatar
Looks cool, I tried shifting the CG rearwards on my larger model, and I could only achieve stable flight at lower speeds, every time I trhew it a little harder it would flip. You said it stalled, so you shifted the accu rearward?

Jul 28, 2010, 05:30 AM
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RdsG's Avatar
@hoverman: My Flatwing's problem is also the rolling. I could clearly see that point where the air cushion is gone because the model start to roll. I had a few hard "landings" because I couldn't turn the craft back with the rudder.

@David22: Thanks

@Derk: Nice TAF model! What kind of camera did you use in this micro wig?
If you need an alternative to wheels, PET slides great on asphalt. Just cut up a PET bottle and glue it on the sliding surface. It last long, perhaps you will never have to change it and it slides like ice.
Last edited by RdsG; Jul 28, 2010 at 06:09 AM.
Jul 28, 2010, 06:11 AM
derk's Avatar
thanks RdsG, its still a work in progress
that is the type of camera, but i have the case removed. it weighs about 11 grams without the case.
what kind of things have PET plastic on them? yogurt cups?
i used the wheels as they were already in the wheel pants from another model so i just glued them on.
with all the finishing and wheels etc, the weight is at 5.6 ounces right now. oh and that includes the balance weight i had to add to the tail i need to make another hatch over the front wing so i can put the battery in there now.

on your rolling problem, i think that the Lippisch models need to drop height during a turn to keep them stable, if its too high the air will escape like you said. but if its a little lower in the turn, it might work okay since the air gap is smaller. or it could catch a wingtip and spin....not sure but something to play with
maybe another video soon guys,
Jul 28, 2010, 06:38 AM
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RdsG's Avatar
Mineral water, cola and other beverage bottles made from PET. Most of them transparent and shiny. These slides better than matte ones.
Last edited by RdsG; Jul 28, 2010 at 06:43 AM.
Jul 28, 2010, 06:50 AM
derk's Avatar
ah i see, i will have to try that on the next one!
Jul 29, 2010, 05:08 PM
Registered User
I could not upload videos to vimeo so try it again on youtube and it paid off,

I put 2 videos of my first ekranoplano rc (super simple)

it simple does not mean that flies well hahaha

ekranoplan test 1 (3 min 40 sec)

ekranoplan test 2 (1 min 13 sec)
Jul 30, 2010, 01:09 PM
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RdsG's Avatar

Nice one! This helicopter propulsion and control is interesting

Let me give you an advice: If you change the horizontal stabilizer's angle of attack to positive (so the h. stab. lifting the rear of the model) and move the center of gravity backwards, it should be more stable, and perhaps it will have more ground clearance.

Jul 30, 2010, 03:12 PM
Registered User
Hi, I wanted find the last element necessary to make the AIRCAT: foam cutting wire, seven three hardware stores electronic stores and two stores and did not find model airplanes, I'm frustrated not to do, without the thread will not have a wing good profile and aerodynamic drag will enmorme, and if I do it with sandpaper my parents will not let me in the amount of bits that is generated.

any suggestions?

pd: the `` foam''that use is extruded polystyrene and measures 120cm 3cmx60cmx


no prove ninguna configuracion mas que la que ves en el video, una semana despues choque con el y se partio el ala, se fue todo a la basura.
Jul 30, 2010, 03:24 PM
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hoverman's Avatar
Haha Jorge,

I like the model, never have seen a Lama coaxial do anything like this but it seems to work nicely . Did you get it flying really? Once you trim it nicely, it seems to ride nicely on it's PAR static cushion, but did you also manage to get real ground effect flying(basically, did you go faster with it)? As Gabriel said, it will need a positive incidence on the stabiliser to be stable.

About the foam cutting, the funny thing is, you are trying to build an aircat, the whole principle about this craft is that it's wing profiles are symmetrical and provide the same pitching moments as flat profiles, it's a sort of worked out bixel. So.....if you can't find the cutting wire..why not use flat profiles?(probably even work just as good or better)

Take a look at the bixel Gabriel build earlier in the thread, it worked great. I also made this drawing a few weeks ago, also a bixel, flat profiles, but with a kinda aircat shape:

Keep on the good work!

Jul 30, 2010, 03:55 PM
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RdsG's Avatar
I don't speak Spanish, but google translator "said" that you crash the model (?) and something about a video.

I am sorry to hear that.

Jul 30, 2010, 04:38 PM
Registered User
hoverman: as I said, the foam is too thick and too much aerodynamic drag opposes.
it could not fly well.

RdsG: yes, I crashed the model, I could not do more evidence that these two videos and the first flight that the battery was at full strength and could fly like a normal plane.

i need finer foam to do anything, which I have only good for the body but I can not keep them at work without the thread.

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