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Old Dec 27, 2012, 06:29 PM
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Singapore, Singapore
Joined Dec 2012
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Originally Posted by tonyastro View Post
Just assembled my HK 450 pro! What are these 2 washers thingies for?
Looks like the rudder servo screw washers. The two of them that have the flat surface towards the servo mount, and the slightly concave surface for the screw head. I just did mine yesterday, and noticed them. They allow for better fit between the flat servo body screw hole and the rounded screw head I suppose.
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Old Dec 27, 2012, 06:58 PM
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Singapore, Singapore
Joined Dec 2012
273 Posts
Dang! I just stripped my cyclic servo! And I don't know what model or make they are. This means that I have to buy and replace all three now. What a pain.

And I'm having another problem with a different heli. When I spool up, even slowly, the heli tends to rotate and face another direction. I can live with that, no issues. When head speed gets faster, the heli still tends to rotate, and no amount of full stick rudder input will stop the rotation. So I figured that the torque effect of the main blades is wayyy greater than the counter thrust that can be generated by the tail blades, even at full pitch, and with my tail slider all the way touching my tail hub. So does this mean that the tail blades aren't spinning fast enough?

I've checked my belt tension, and did the "push it over the middle line" test. My main gear and autorotation tail drive gears are 150T and 109T respectively, pretty normal. I've replaced my tail blades with balanced CF rigid tail blades. I've made sure that the tail servo can shift the tail slider to the full extents on the tail shaft, and I'm sure that my gyro is set up correctly in HH mode. My main blades are balanced, tracked,swash is level, and the heli flies alright when I replace the blades with the Align 290mm ABS blades. Problem comes only when I use plastic 325mm blades.

I thought that the 325mm blades were too heavy coming in at about 35g per piece, while the Align blades are only about 22g per piece. But isn't 325mm a standard size for blades? How can it generate a torque effect so great that even my tail rotor can't counter?

I'mma chop the 325mm blades to 290mm and see if it changes anything. Hopefully it stops the rotation. Any help would be greatly appreciated.
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Old Dec 27, 2012, 07:27 PM
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Quote:
Originally Posted by perdification View Post
Dang! I just stripped my cyclic servo! And I don't know what model or make they are. This means that I have to buy and replace all three now. What a pain.

And I'm having another problem with a different heli. When I spool up, even slowly, the heli tends to rotate and face another direction. I can live with that, no issues. When head speed gets faster, the heli still tends to rotate, and no amount of full stick rudder input will stop the rotation. So I figured that the torque effect of the main blades is wayyy greater than the counter thrust that can be generated by the tail blades, even at full pitch, and with my tail slider all the way touching my tail hub. So does this mean that the tail blades aren't spinning fast enough?

I've checked my belt tension, and did the "push it over the middle line" test. My main gear and autorotation tail drive gears are 150T and 109T respectively, pretty normal. I've replaced my tail blades with balanced CF rigid tail blades. I've made sure that the tail servo can shift the tail slider to the full extents on the tail shaft, and I'm sure that my gyro is set up correctly in HH mode. My main blades are balanced, tracked,swash is level, and the heli flies alright when I replace the blades with the Align 290mm ABS blades. Problem comes only when I use plastic 325mm blades.

I thought that the 325mm blades were too heavy coming in at about 35g per piece, while the Align blades are only about 22g per piece. But isn't 325mm a standard size for blades? How can it generate a torque effect so great that even my tail rotor can't counter?

I'mma chop the 325mm blades to 290mm and see if it changes anything. Hopefully it stops the rotation. Any help would be greatly appreciated.
When I encountered the same situation, I checked the gyro direction and bump up the throttle curve to get higher speed (if the motor KV and pinion are known to be correct ones. i.e 3500Kv, 13T).
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Old Dec 27, 2012, 07:36 PM
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Singapore, Singapore
Joined Dec 2012
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Originally Posted by rchobbyfly View Post
When I encountered the same situation, I checked the gyro direction and bump up the throttle curve to get higher speed (if the motor KV and pinion are known to be correct ones. i.e 3500Kv, 13T).
I'm running the exact same motor and pinion set up that you mentioned. I've upped the throttle curve, such that at lower stick values, higher head speed is obtained. No help...
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Old Dec 27, 2012, 08:36 PM
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Joined Oct 2010
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Quote:
Originally Posted by perdification View Post
Dang! I just stripped my cyclic servo! And I don't know what model or make they are. This means that I have to buy and replace all three now. What a pain.

And I'm having another problem with a different heli. When I spool up, even slowly, the heli tends to rotate and face another direction. I can live with that, no issues. When head speed gets faster, the heli still tends to rotate, and no amount of full stick rudder input will stop the rotation. So I figured that the torque effect of the main blades is wayyy greater than the counter thrust that can be generated by the tail blades, even at full pitch, and with my tail slider all the way touching my tail hub. So does this mean that the tail blades aren't spinning fast enough?

I've checked my belt tension, and did the "push it over the middle line" test. My main gear and autorotation tail drive gears are 150T and 109T respectively, pretty normal. I've replaced my tail blades with balanced CF rigid tail blades. I've made sure that the tail servo can shift the tail slider to the full extents on the tail shaft, and I'm sure that my gyro is set up correctly in HH mode. My main blades are balanced, tracked,swash is level, and the heli flies alright when I replace the blades with the Align 290mm ABS blades. Problem comes only when I use plastic 325mm blades.

I thought that the 325mm blades were too heavy coming in at about 35g per piece, while the Align blades are only about 22g per piece. But isn't 325mm a standard size for blades? How can it generate a torque effect so great that even my tail rotor can't counter?

I'mma chop the 325mm blades to 290mm and see if it changes anything. Hopefully it stops the rotation. Any help would be greatly appreciated.
sounds like the pitch slider isn't set right then setup the pitch in rate mode and then flip it to hh mode and it should be good to go.
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Old Dec 27, 2012, 09:20 PM
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Originally Posted by pmerritt View Post
sounds like the pitch slider isn't set right then setup the pitch in rate mode and then flip it to hh mode and it should be good to go.
The problem is even with full rudder input to counter the effect of the main blades, the torque effect is still greater than the thrust that can be produced by the tail rotor. So if even my full stick input can't counter the torque effect, I don't think the gyro can do it's job.
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Old Dec 27, 2012, 09:33 PM
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Singapore, Singapore
Joined Dec 2012
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Okay so this is what I did:

I chopped off 35mm worth of my plastic 325mm blade, shortening it down to 290mm just like the Align ABS blades, and now it works fine. So I guess that my 450 Helicopter can't take 325mm blades worth of torque effect. Now this is weird. I thought the standard length was 325mm?
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Old Dec 27, 2012, 10:23 PM
Beginner Pilot
United States, NY, Coram
Joined Jul 2012
374 Posts
I think it sounds like your gyro is reversed perdi, did you check that?
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Old Dec 27, 2012, 10:24 PM
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United States, NY, Coram
Joined Jul 2012
374 Posts
Or something in the tail was stuck, not smooth, know what i'm saying?
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Old Dec 27, 2012, 10:25 PM
Beginner Pilot
United States, NY, Coram
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Belt? Is it tight? No stripped teeth? Something like that. I do not see what cutting 35mm off main blades would do.....
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Old Dec 27, 2012, 10:45 PM
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Originally Posted by gs550t1981 View Post
Belt? Is it tight? No stripped teeth? Something like that. I do not see what cutting 35mm off main blades would do.....
Hey pal,

I have a set of Align 290mm ABS, works perfect with my heli. When I replace it, without changing any settings on my heli, with 325mm blades, the problem sets in, so Im pretty sure my gyro settings and stuff are all okay. Having shorter blades and thus making it lighter reduces the torque effect, thus allowing the tail rotor to cope.
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Old Dec 27, 2012, 10:46 PM
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Toronto (Don Mills), Canada
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Also tail spinning the right way? It should move up on the front side when you rotate the head in the normal direction.

Tail blades not on backwards?

Once the heli has spooled up the weight of the blades has absolutely no effect on the amount of torque the tail has to overcome.
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Old Dec 28, 2012, 02:55 AM
Team Mulikow 3D
Oxfordshire, UK
Joined Jan 2007
4,098 Posts
Having shorter blades reduces the amount of torque that the tail has to counter. We need more information to help you though ...
Motor ?
Pinion ?
Throttle curve ?
Tail servo (make and model) ?
Any binding in the tail with the sevo disconnected ?
Belt tension correct ?

Good luck,
Mike
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Old Dec 28, 2012, 04:05 AM
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Originally Posted by pmackenzie View Post
Also tail spinning the right way? It should move up on the front side when you rotate the head in the normal direction.

Tail blades not on backwards?

Once the heli has spooled up the weight of the blades has absolutely no effect on the amount of torque the tail has to overcome.
Sorry, but could you elaborate on what it means by no effect? Is it that the torque effect of the main blades is insignificant compared to thrust generated by tail blades?

Quote:
Originally Posted by MikeHRC View Post
Having shorter blades reduces the amount of torque that the tail has to counter. We need more information to help you though ...
Motor ?
Pinion ?
Throttle curve ?
Tail servo (make and model) ?
Any binding in the tail with the sevo disconnected ?
Belt tension correct ?

Good luck,
Mike
Thanks guys, I think it's the tail blades installed the wrong way. Although I can't really tell whether that's the fix because I had already chopped off the 325mm blade to 290mm and it works fine no matter which direction I install the tail blades. Don't have any other 325mm blades to test now, longest is 315mm Align blades and they work fine too. Just to be sure, it's the trailing edge of the tail blades facing the main rotor when it's in the upright position? I followed this: http://www.rotorfx.com/scale_model_r..._logo_0001.jpg
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Old Dec 28, 2012, 07:48 AM
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Toronto (Don Mills), Canada
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Quote:
Originally Posted by perdification View Post
Sorry, but could you elaborate on what it means by no effect? Is it that the torque effect of the main blades is insignificant compared to thrust generated by tail blades?


Earlier you said that the weight of the blades would affect how much torque the tail would have to overcome.

That is only true for a few seconds while they are spinning up.
Once the head is up to speed the only forces resisting rotation are aerodynamic loads. They would be higher for the longer blades, but the weight of the blades would have no effect.

Pat MacKenzie
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