Hawk Pro Vibrations...
07-09-2006, 06:02 AM
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Hawk Pro Vibrations...
Greetings,
First i'ld like to thank everyone in this forum for their great support... the hawk pro is a wonderful machine, i've been doing some serious flying with it and it's stable like a rock, a very easy heli to fly.
Now considering the troubleshooting part of the post, i'm having some vibrations when the heli is in the air, obvious vibrations that are far from normal. I've tried removing the main blades, but keeping the flybar, and turning on the engine with a bit of throttle on the ground, the heli still vibrates. Removing the flybar kind of reduces the vibrations but the integrity of the heli doesn't feel right. Has anyone experienced unusual vibrations on the hawk before? The main blades are very well balanced, the flybar as well, and the flybar pitch angles are the same on both sides. could the vibrations be caused by some loose gears? the hawk has never experienced any crashes, and that vibration didn't exist before my last flight yesterday... any input would be appreciated, thanks people
First i'ld like to thank everyone in this forum for their great support... the hawk pro is a wonderful machine, i've been doing some serious flying with it and it's stable like a rock, a very easy heli to fly.
Now considering the troubleshooting part of the post, i'm having some vibrations when the heli is in the air, obvious vibrations that are far from normal. I've tried removing the main blades, but keeping the flybar, and turning on the engine with a bit of throttle on the ground, the heli still vibrates. Removing the flybar kind of reduces the vibrations but the integrity of the heli doesn't feel right. Has anyone experienced unusual vibrations on the hawk before? The main blades are very well balanced, the flybar as well, and the flybar pitch angles are the same on both sides. could the vibrations be caused by some loose gears? the hawk has never experienced any crashes, and that vibration didn't exist before my last flight yesterday... any input would be appreciated, thanks people
07-09-2006, 02:26 PM
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RE: Hawk Pro Vibrations...
It's always tough to debug vibes...
In spite of never having crashed, I'd still go over all of the shafts; are they all straight?
As I understand, you've pulled both the main rotor blades and flybar off of the head. In this case, does the head turn true; i.e. does the hole in the top of the head rotate about it's center, or does it orbit/wobble around? If yes, then either the main shaft is bent, or the head is not running true on the main shaft.
If the vibration occurs w. the blades on and goes away when they're off, then:
1) are the blades tracking well?
2) if the tracking changes as pitch is increased, then the spindle/head axle may be bent.
Another thing that helps is to consider the frequency of the vibration:
1) low frequency that affects the whole heli is most likely the main rotor head (mainshaft, flybar, etc)
2) medium frequency is usually the tail rotor (this will cause the tail to vibrate up and down at a high frequency)
3) high frequency is usually the motor and its components (e.g. fan, clutch, etc.) ( this will usually cause the fins to buzz at their tips)
Any additional information about thing's you've tried would always be helpful...
Good luck,
SteveR
In spite of never having crashed, I'd still go over all of the shafts; are they all straight?
As I understand, you've pulled both the main rotor blades and flybar off of the head. In this case, does the head turn true; i.e. does the hole in the top of the head rotate about it's center, or does it orbit/wobble around? If yes, then either the main shaft is bent, or the head is not running true on the main shaft.
If the vibration occurs w. the blades on and goes away when they're off, then:
1) are the blades tracking well?
2) if the tracking changes as pitch is increased, then the spindle/head axle may be bent.
Another thing that helps is to consider the frequency of the vibration:
1) low frequency that affects the whole heli is most likely the main rotor head (mainshaft, flybar, etc)
2) medium frequency is usually the tail rotor (this will cause the tail to vibrate up and down at a high frequency)
3) high frequency is usually the motor and its components (e.g. fan, clutch, etc.) ( this will usually cause the fins to buzz at their tips)
Any additional information about thing's you've tried would always be helpful...
Good luck,
SteveR
07-09-2006, 07:40 PM
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RE: Hawk Pro Vibrations...
Been There, Seen It, Fixed it.
I too had the same experience and found the injection molded clutch and fan assembly was way out of center and not nearly balanced. Put it in my lath and center drilled the hole then mounted on a the balancer to find it out I had to drill two 1/16" dia. holes of material off ONE side. Reassembled and vibration gone.
Bottom line, I replaced the injection molded fan and clutch hub with aluminum my next maintenance time and they were dead on.
Hope this helps!
I too had the same experience and found the injection molded clutch and fan assembly was way out of center and not nearly balanced. Put it in my lath and center drilled the hole then mounted on a the balancer to find it out I had to drill two 1/16" dia. holes of material off ONE side. Reassembled and vibration gone.
Bottom line, I replaced the injection molded fan and clutch hub with aluminum my next maintenance time and they were dead on.
Hope this helps!
