How long is to long?

[Dilbeck]

How long is to long for the main rotor blades? I mean if the engine can handle the load then when comes the point that it is to much for the tail boom or fly bar? I took my Hawk pro with an os37 that came stock with 550mm blades, I put 600mm carbon fiber blades on it and it settled down real nice in crusing around and in a hover I mean it was night and day differance how well it handled. There seemed to be one catch, The tail seemed to drift somewhat as if it was being affected by the extra length of the main rotor blades. The 550s and the tail blades stretched out nose to boom came together but did not overlap. The 600s overlaped the tail blades by approx 2-3 inches. I wondered if the down wash from the main blades was counteracting the tail blades. I keep adjusting the gy401s servo linkage but could never get it to be rock steady like it was before. Any thoughts or past experience would be great.

[Coolice]

Hey,

You may find it's the increased torque of the main rotors having an effect on the tail rotor repsonse and performance rather than the increased wash. If anything I'd be inclined to say the increased downwash from the main rotors will help the tail to a degree as it provides more air for it to bite into.

The other thing which springs to mind is the rotor rpm, are you running the same as before? If not then this will also effect the tail rotors performance as it will probably be turning slower and hence not have the power/authority it once had with the 550's.

The larger rotor disk will make the model feel much smoother in the air, almost as if the machine is flying on rails and this is what I experience with the Predator Turbine model I fly when I switched from 720mm mains to 800's.

Reading your post more I'm inclined to go with the reduction in rotor rpm or the torque increase on the helis fuselage from the longer rotor blades. An option you could try is longer tail blades, but then you will probably run the risk of them hitting the mains in flight. But if your not into hard 3D and run hard head dampers you may get away with it ok.
In any case you could give it a go and see if there is an improvement.
.

[Dilbeck]

You know it turned out you were correct, Thanks, It wasent the blades effecting my 401 gyro it was a binding in the slider itsself fixed and flew like it was on rails. Thanks clint......

[Coolice]

Hey,

Ah, that will do it and cause tail problems. On my Swift I chased a gyro holding issue a little while back which turned out to be a broken down tail grip bearing hence it was locking up under load.

Glad you found it to keep flying anyway.
.

[capebob]

If your main rotor blades overlap your tail rotor blades you are headed for disaster. Any aerobatics involving negative pitch or even a more firm than normal landing will cause your main rotor blades to impact your tail rotor blades.

Bob

[theLane]

Ya, that's kind of what I was thinking too :)