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Old Yesterday, 06:20 PM
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Those are not really thrust lines. Draw the lines along the nozzles and perpendicular to your CG line, and those are the contributions to yaw. With equal thrust from both nozzles, they cancel out.
Quote:
Originally Posted by okke dillen View Post
This thrust line layout could possibly help (as it creates no momentum):

Cheers,
o.d.
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Old Yesterday, 07:04 PM
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I think he is saying those are the lines you NEED to have one motor able to drive the plane straight still.
You would achieve that via TV offset of each nozzle.

By looking at the T-50 it seems they might not need that much angle in reality. Maybe some other factors add up that a lower angle is the truly best result, for all situations - one engine dead or not.

I don't think having those offset nozzles (eg outwards) would alter your total power under normal flight at all. Pretty well negligible issue.
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Old Yesterday, 07:12 PM
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Oh, which reminds me I had a motor fry back in the very first flights (with L2855-2100kv) and in flying terms it didn't bother me at all. But all I had to do was come around the circuit - at less then max power - and seeing that was mainly descending anyway the thrust level (single fan) would have been 30% region I expect.
I also did not use high power because if a motor fried you could continue to be feeding a 'unfriendly electrical setup' then! (the dead/shorted motor) hehe. So the least power used from then on the better.

Though I stalled and crashed it from 5 ft anyway, by coming in too slow on the near dead stick.
So I guess I never got to see what 100% throttle on one fan would have done.....
For the 'shorting' reasons it is best to use NO power if possible!
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Old Yesterday, 07:16 PM
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Quote:
Originally Posted by okke dillen View Post
yes, the remaing performance will be approx cos (alpha). With alpha being approx 10, cos(10) =0.9848... resp 98.5%.
If the whole duct was angled in that 10 fashion then it would be so, but since it's just the nozzle deflecting airflow at the end my guess is the loss would be much higher.

The top speed of the aircraft would be specially affected because of unclean ducting setup.

Quote:
Originally Posted by Maxthrottle View Post
Why would you need two YAW TV servos if one engine goes down?
I was considering the case where you usually fly with nozzles straight but with the ability to cant outwards in case of need.

Quote:
Originally Posted by Maxthrottle View Post
I'll keep it in mind that if I do flame out hard rudder but not full throttle? Or do you figure it's an unwinnable scenario if you're starting off too slow......
I don't think it is unwinnable unless you have very low speed, altitude and room for landing combined at the same time

If you do hard rudder it also gets very unstable. That's what I did, so I can tell
Specially when pulling up and down on pitch, the working nozzle will be introducing a roll deviation when full-throttle that is difficult to deal with.

I don't know what the best course of action may be. If you can go by without using full-throttle, that's definitely a good thing.
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Old Yesterday, 07:20 PM
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Oh well... setup a "Flame out mix" - left and right version. LOL.
So it sets up ALL controls to optimise one engine out, and your aim - and only path you should take - is to fly it sedately back to land then!
With a twin throttle wiring setup and mix you can even test it out to tune all the settings.

Yawn... even too much effort to ever bother for ME! So I will assign ZERO effort to this possibility and priority!
I will just 'make it work' manually on the fly at the time! LOL
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Old Yesterday, 08:31 PM
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Quote:
Originally Posted by SU-4ever View Post
...I was considering the case where you usually fly with nozzles straight but with the ability to cant outwards in case of need.
....
still don't get that. If you have a single yaw TV servo and one flame out, the flame out has no thrust and is thus doing nothing. So you yaw or can't the other to counter the offset moment.

Hard over rudder would be a stability issue unless you get used to crabbing and arresting any yaw induced roll.

But the split second lots can happen as it did on a number of your crashes. Still remember the video of Svet coming g down with the TV left in the pitched up position.
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Old Yesterday, 08:41 PM
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I just bought 2 Polarizing Smart Phone detachable filters on ebay

http://www.ebay.com/itm/261534638205...84.m1427.l2649

http://www.ebay.com/itm/261555413474...84.m1427.l2649


Quote:
Originally Posted by okke dillen View Post
cool moving pilot head ITTD!
About the glare: try a piece of linear polarized sun glass sliver in front of the lens. Rotate it until the glare is gone. Try it, the result will be stunning

Cheers,
o.d.
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Old Yesterday, 08:59 PM
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Via ITTD's link above, I found a 'aircraft' protection bag/outfit' for the Su-35 !

http://www.ebay.com/itm/Sexy-Lace-Li.../261567296646?
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Old Yesterday, 10:38 PM
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OK, that makes more sense. It would seem the toe-out of the nozzles doesn't need to have the thrust lines converge at the center of mass, just enough for the flight computer to be able to compensate for lateral drift with other control surfaces without as much drag penalty.


Quote:
Originally Posted by PeterVRC View Post
I think he is saying those are the lines you NEED to have one motor able to drive the plane straight still.
You would achieve that via TV offset of each nozzle.

By looking at the T-50 it seems they might not need that much angle in reality. Maybe some other factors add up that a lower angle is the truly best result, for all situations - one engine dead or not.

I don't think having those offset nozzles (eg outwards) would alter your total power under normal flight at all. Pretty well negligible issue.
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