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SU-27 CG aft of CP, mandatory GYRO?

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Old 02-23-2018, 02:32 PM
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amckevitz
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Default SU-27 CG aft of CP, mandatory GYRO?

premise 1: the SU-27 CG is aft of its Center of Pressure.
premise 2: the su-27 has 4 redundant systems of fly by wire to make the thing fly.

Has anyone flown or know of any model like this where a gyro is mandatory because cg location is, guessing something like 60% MAC? No I don't have the actual CG location of the full scale. It baffles me learning it's aft of the CP.

the F-16 could be the same way. It's inherently unstable is some regard.

i have a 19" span su-27 that I'm just nuts over. Squirrely thing. I've never used a gyro before. I might try this moving cg from the 27-30% MAC that it is now to more aft and use a gyro to simulate full scale. It's not exactly comfortable now, due to size and wing loading (34oz/sqft). I can tell that I like flying more aft over fwd of this. It could fly better lighter. That's not what this post is about. I like realistic wing loading and flying planes. I'm more rewarded flying this little thing. The shaking? Oh I'm just happy. It's not nerves. Lol

All you jet guys use gyros right? I'll probably get one for general stability.. if this doesn't work out.

Im building a 53" span foam twin 90mm edf SU-27, and wonder about gyros and this AFT CG location. I do not want to crash this one! It's nice!

if I can duplicate the small one, CG aft of CP, then I'm up to trying on the big one. I'm not crazy about pioneering it. Maybe gyros are typically off for takeoff. I doubt that I could keep it off for this setup that I'm referring to. Which brings me here to see what you think!

100A wires going 4' can be shorter if CG is more aft and I don't need to put the batteries under the canopy. There's a practical item. Anyway,

Your opinion please!

andy
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Old 03-07-2018, 02:46 AM
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JohnMac
 
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Many modern fighers have a rearward cg location and the stability comes from computers and sensors. I have flown quite a few jets based on such aircraft. We do not try to emulate the CG of the full size aircraft. We put the cg in the normal position. This then loads the horizontal stabiliser and thus we get normal lontitudinal stibility.
We use Gyros for dealing with gusty conditions, or for 3D flying.
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Old 03-07-2018, 02:44 PM
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Joseph Frost
 
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Gyros in planes? Seem to me the cheaper the gadgets get the more people use them. It's all up to the skills of individual pilot. I know of a bloke fitting 2 gyros on Ails. in 20+ grand model and was lucky to bring it back after only one circuit.
I fly at least 20 jets of every kind and use "20 year old Piezzo" gyro only in one turbine powered delta with no Rudders, hooked on the nose gear to help steering it strait while taking off.
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