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Old May 04, 2013, 07:35 PM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
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90mm Sport Jet --5th Generation Fighter Style FINALLY A GOOD VID

I`ve been kicking around building a 90mm size Sport Jet that combines the features that I like from some of the 5th gen fighters and prototypes (F-22, YF-23, F-35).

I did some sketches the other day and decided it had enough promise to build a 30mm sized edf to test the concept and to see it in 3D.

Today I sat down with some 3mm depron and threw something together. It`s a flyable rough prototype. Nothing fancy.

I`m going to look it over for a while and see what changes would help the looks.

I`d also welcome suggestions and opinions. Positive and negitive input is welcome, but if you don`t like something try to tell me why, and what you`d suggest to fix it.

Anyway, here it is. Fire away.
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Last edited by Knife Liddle; May 09, 2013 at 08:16 PM.
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Old May 04, 2013, 07:39 PM
2014 EDF JET JAM We be Jamming
Kevin Cox's Avatar
St. Louis Intl, Missouri, United States
Joined Jan 1997
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Nice Lee!!
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Old May 05, 2013, 06:31 AM
michigan jet guy
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USA, MI, Caledonia
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I like it. It's different. I hope it flies well. Phil
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Old May 05, 2013, 01:38 PM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
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Thanks for the input guys. I`m thinking that the wing is bigger than it needs to be and that the fuselage could be a little larger. It will need to be deeper to hold a 90mm.

Getting some gear in it. I`m just going with elevons on this to keep it simple. A 90mm would have ailerons and rudder-vators on the V-tail. Then mix in flaperons if it needs some help on landing.

If the wind lays down some this PM I`ll see if I can get some flight vid.
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Old May 05, 2013, 02:18 PM
EDF rules... :)
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Joined Nov 1999
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Nice work.
I came across one several months back you might like.
It is called the Mig49 'Frostbite'.

http://sketchup.google.com/3dwarehou...84&prevstart=0

Eric B.
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Old May 05, 2013, 03:50 PM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
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Yeah, that`s a nice looking concept. Thanks for the link Eric.

Got her RTF. The AUW with a 450mah 3s is 110g and it has about 90% t/wt ratio. I may cut a cheater hole in the bottom to boost thrust a little. The wing isn`t strong enough for a bunch of speed, so I`m more interested in thrust.

With a 3s 950mah the weight goes up to 138g but the flight time would be 6min or so. But at the higher weight th/wt drops quite a bit of course. I`ll try it at 110g first and see how it goes.
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Old May 05, 2013, 04:11 PM
Lee Liddle
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Carrollton, Tx
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Cheater hole helped some. Now it`ll just support its weight at 110g.
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Old May 05, 2013, 04:12 PM
DELTAS RULE
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tehachapi, CA
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Looks cool lee! Should fly good!
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Old May 05, 2013, 04:42 PM
Lee Liddle
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Carrollton, Tx
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Thanks Brent. I was looking at this thing at HK, for a 90mm starting point, but it was just too far off. Would probably be way too nose heavy too judging by the fan location.

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Old May 05, 2013, 05:51 PM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
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I did a maiden and it flew well. CG was dead on (I did glide tests when it was just depron and 1oz). The roll was pretty hot at first so I went to low rate and that fixed it. Pitch was good. It was pretty fast so the wings were flapping some in the gusty wind. So I added a carbon spar that is flat and wide, so I just sliced the wing and glued it in vertically. I should be able to throw it around a little better now. Will get some vid on the next flight.
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Old May 05, 2013, 06:12 PM
Team EJF >>>WHOOSH>>>
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Quote:
Originally Posted by Knife Liddle View Post
Thanks Brent. I was looking at this thing at HK, for a 90mm starting point, but it was just too far off. Would probably be way too nose heavy too judging by the fan location.
They don't fly worth a darn either.
Several models were tested here in AZ by big names (Bob Ruff, Mike Donovan, etc.) and each one proved very unflyable. Not their fault at all... the design is sketch, inherently unstable, etc.

Yours looks more thought out and proportional. Good luck with this one, looks fun!
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Old May 05, 2013, 06:37 PM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
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Thanks Vic. I put some gray paint on it and got some video. It`s very gusty and there is a very strong roller right were I`m flying so it looks crazy, but for a 4oz jet it`s doing very well. Should be a blast when the wind is decent.

I`m uploading to You Tube now and when I edit my ugly face out of the vid, i`ll post it. LOL
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Old May 05, 2013, 07:38 PM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
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I took this video down because it was so lame. The other one is passable, but I`m going to try another video when I get some good conditions.
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Old May 05, 2013, 07:47 PM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
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I splattered some paint on it. It was a fun weekend project that worked out. Now I have another backyard flier and maybe sometime I`ll make a big one.
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Last edited by Knife Liddle; May 05, 2013 at 09:06 PM.
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Old May 06, 2013, 09:01 AM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
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Got to fly it in calm conditions this morning. Much more fun to fly. It needs somefine ttuning on cg and some aileron differential to straighten out the roll axis, but over all it flies great.

It has much better performance at 110g than it does at 140g. I'm surprised at the difference, but it's very obvious.

I'll get some better video soon. It looks very much the part of a 5th gen fighter in the air. I think that most people would swear that they are seeing a scale F-22.
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