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Old Nov 29, 2010, 07:14 PM
Air Head is online now
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High Alpha Flight


While all you guys are trying to break 200 miles per hour ( or is it up to 210 now).

What about something like this.....How about a high alpha slow speed ducted fan model.

What sort of thrust to weight would I need to do some slow speed high alpha flight maneuvers....????
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Old Nov 29, 2010, 07:38 PM
Richie Simpson is offline
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If you have to ask....<g>


Without a variable exhaust nozzle it is not possible with a jet. No airflow over control surfaces.
That said delta wings are more forgiving, search for sapac Saab gripen for the best I have seen.
Old Nov 29, 2010, 07:54 PM
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Any modern jet is capable of high-alpha flight without TVN.

TVN is only required if you want to hover your jet at zero-airspeed, which is otherwise known as 3D flying.
Old Nov 29, 2010, 10:12 PM
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Quote:
Originally Posted by Air Head View Post
While all you guys are trying to break 200 miles per hour ( or is it up to 210 now).

What about something like this.....How about a high alpha slow speed ducted fan model.

What sort of thrust to weight would I need to do some slow speed high alpha flight maneuvers....????
thrust to weight ratio would have to be 1 to 1.
Old Nov 29, 2010, 11:14 PM
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Not really 1 to 1 but it helps to maintain alt. if your too slow..My old Kyosho Mirage would high alfa but if you got to slow and low you could not recover to level flight easy
Old Nov 29, 2010, 11:22 PM
Bob Reynolds is offline
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Many, many years ago, My son, David, won the slow flying award at the Denver Jet rally at 16.4 mph. He was flying his own design "U-Who" with his own designed 4" fan. A picture of this plane appeared in RC Jet International, May 2001.
Old Nov 29, 2010, 11:50 PM
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Last edited by crypto666; Nov 30, 2010 at 12:37 AM.
Old Nov 30, 2010, 06:36 AM
Neil Guildford is offline
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My Tamjets F-16 1:8 will do a slow high alpha pass at its current weight of 20.5lb.
Old Nov 30, 2010, 01:55 PM
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It's been done. Here is my video of my own design.
360 Thrust vectoring with 64mm EDF RC F-22 Foamy (2 min 42 sec)


I modified it even more and am practicing on slow inverted high alphas.
Old Nov 30, 2010, 02:09 PM
Erik v. Schaik is offline
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I have seen the Lubach F16 in 80 degrees high alpha. One needs vertical climbout to recover from this angle. Lightweight and critical CG is the only option. He used minifan,16/15/3 and 4s1800mAh.
Old Nov 30, 2010, 02:14 PM
Erik v. Schaik is offline
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Quote:
Originally Posted by Richie Simpson View Post
Without a variable exhaust nozzle it is not possible with a jet. No airflow over control surfaces.
That said delta wings are more forgiving, search for sapac Saab gripen for the best I have seen.
I think that is feasable A variable exhaust nozzle is a nogo IMO. The gain is in the intake design.
Old Nov 30, 2010, 02:34 PM
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As said before, detla wings are the most forgiving. Jets with little taper (think L-39) may want to snap.
The main requirement is to have a rudder and use it to correct the trajectory as the nose starts to drop to the side. Ailerons cause adverse yaw: the wing that you are trying to lift gets more drag, so the plane yaws to that side.
You can do a nice high-alpha with not a lot of power. A pretty decent high-alpha will require lots more, but not 1:1. 1:1 (or a little more) is nice to get out of high-alpha: punch the throttle and release elevator. With less thrust, you have to let the nose drop and regain airspeed, losing some altitude in the process.
It is a fun manuver and very useful to know.
M.-
Old Nov 30, 2010, 02:38 PM
Erik v. Schaik is offline
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What angle do you consider high alpha?
Old Nov 30, 2010, 03:15 PM
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My GWS J-10 with working canards is awesome at high alpha.

F16s are great for high alpha slow flight. Don't understand why though. Very tempting to catch rather than land. Doesn't always end well.

High Alpha Disaster (0 min 55 sec)
Old Nov 30, 2010, 05:03 PM
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Here is my build TWM J10B with TV from rc-lander.
Works fine!!

http://www.youtube.com/watch?feature...&v=69CdmOd5KGo

Regards
George


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