Wingservos.
12-22-2006 | 04:20 PM
#26
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From: Oudtshoorn, SOUTH AFRICA
RE: Wingservos.
Hi Anders,
As David pointed out that the power output of the servo is too little for the job. I have used bearing mounts on aileron horn and servo horn. No slop. The upgrade from P-80 to P-120 was the problem. I should have changed the servo's to 8411 or 8511's.
In a chain of events the weekest link will fail....
Regards
Morne
As David pointed out that the power output of the servo is too little for the job. I have used bearing mounts on aileron horn and servo horn. No slop. The upgrade from P-80 to P-120 was the problem. I should have changed the servo's to 8411 or 8511's.
In a chain of events the weekest link will fail....
Regards
Morne
12-22-2006 | 04:58 PM
#27
Senior Member
RE: Wingservos.
Hi Morn
Yes the chain is our problem...
Just wondering if the flutter was a result of the servo or not. What started the chain?
Maybe the model was passing it's structual limit?
Like you and David says, putting in a bigger and stronger servo pushes the limit forward, but will not solve the problem if the rudder is not properly balanced, just move the limit a little.
Still no friend of small servos...
Regards
Anders Wikman
Yes the chain is our problem...
Just wondering if the flutter was a result of the servo or not. What started the chain?
Maybe the model was passing it's structual limit?
Like you and David says, putting in a bigger and stronger servo pushes the limit forward, but will not solve the problem if the rudder is not properly balanced, just move the limit a little.
Still no friend of small servos...
Regards
Anders Wikman
12-24-2006 | 07:16 AM
#30
RE: Wingservos.
My Skymaster Hawk is Jetcat 160 powered with the following servo spec:
Ailerons, JR9411, rudder, JR 8511 (mounted in the fuselage below the fin) stab, twin 8411s could be replaced by a single 8711.Flaps, 8411, No trace of flutter on any control surface but SOME mass balancing was added to the stab. to ease the load on the servos.
........................and do beware of the AWFUL cheap plywood aileron servo mounts. In my review article for RCJI I suggested they be binned and yet I saw someone flying a Hawk at Cottesmore this summer, and sure enough a servo mount failed when the ply delaminated.
I don't think the rudder needs balance with a powerful servo and slop free linkage. The 8511 does push the flutter speed a LOT forward, well beyond any speed at which the Hawk is likely to be flown.
JR 3301s and 3421s etc. are excellent small servos, perfect for sailplanes !
Regards,
David Gladwin.
Ailerons, JR9411, rudder, JR 8511 (mounted in the fuselage below the fin) stab, twin 8411s could be replaced by a single 8711.Flaps, 8411, No trace of flutter on any control surface but SOME mass balancing was added to the stab. to ease the load on the servos.
........................and do beware of the AWFUL cheap plywood aileron servo mounts. In my review article for RCJI I suggested they be binned and yet I saw someone flying a Hawk at Cottesmore this summer, and sure enough a servo mount failed when the ply delaminated.
I don't think the rudder needs balance with a powerful servo and slop free linkage. The 8511 does push the flutter speed a LOT forward, well beyond any speed at which the Hawk is likely to be flown.
JR 3301s and 3421s etc. are excellent small servos, perfect for sailplanes !
Regards,
David Gladwin.
12-24-2006 | 08:02 AM
#31
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From: KENILWORTH, UNITED KINGDOM
RE: Wingservos.
Could be the B***s to the wall speed attitude of some pilots contribute part of the problem and inadequate servos contribute the other part.
Happy Christmas Dave.
Happy Christmas Dave.
