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cobieg · 02-08-2014, 11:41 AM

What is a good head speed for a 450 size 5 blade rotor head.
Keyrigger, I trust your knowlage.

Keyrigger · 02-08-2014, 01:43 PM

I'm sure others will have some thoughts, too, but my personal preference is to keep a multi-blade at around 2000 to 2200 with a three blade head maybe a bit higher at 2300. Most gearing is easily accommodated with motors from 2400 right up to 3400 to give you head speeds at that level. You really need to look for an online or downloadable calculator (Mr, Mell's is a good one) and plug in a motor with your main gear and pinion options. Even I was surprised that a 3400 could be tamed to that level and with a governor capable ESC, you can set it and forget it. Who knew? Hope this helps.

Don

bdfox1 · 02-09-2014, 01:22 AM

Don's advice is pretty much right on from what I can find out.

I have just finished a 450 scale heli with a 3 blade head. I am running a 2900 KV motor with 11T pinion, 121 T main gear on 3S. My head is a CopterX rigid one and I am using their very inexpensive molded blades. I am using the latest Align tail blades that are 68 mm long.

I easily get off the ground with even 2250 with the fuselage on it. But I feel like it likes 2300 better withthat extra weight. I have an additional load on it with a water tank and pump and it does get off the ground fine on 2300 but I think it feels better at 2350. But not many hops in yet to verify that.

But what that says is that these are the target ranges to be fooling around in. Not 3400!!!

As soon as it warms up a bit (hopefully next week) I can maybe get out to try some more experiments in settings and might find that I can cut it back again.

Bags of fun.

-Barry

bdfox1 · 02-13-2014, 02:29 PM

So throw out all those comments I made.

Now that I have my pitch curve in the ballpark (well closer at least) I find that I am down to 2250 and it flies just fine. So the next exercise is to move all the governor settings down again and try it even lower.

I have hunch that lower isn't going to be much lower as I can see just the slightest little tail wag at times so maybe the tail speed is getting to where it won't hold. But maybe a little gain change will fix that too. It really isn't much. Might end up being a slight gyro setting change as well. The only thing I find with the lowest RPM so far is that my efficiency is dropping off a touch and the current draw and temps are going up just a little. I ran the numbers through the calculator on the ESC software and dropping the KV on the motor by 200 (because I can find a motor at that speed) and then gearing the pinion up one tooth I can get the same head speed and a 5% bump in efficiency back into the low 90% range. That should help bring the temp back down.

Lots of fun experimenting.

-Barry

02-08-2014, 11:41 AM	#1 (permalink)
cobieg Registered Users Join Date: Aug 2012	450 size multi blade rotor head speed What is a good head speed for a 450 size 5 blade rotor head. Keyrigger, I trust your knowlage. __________________ I didn't crash. I just ran out of airspeed, altitude, and idea's all at the same time.

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02-08-2014, 01:43 PM	#2 (permalink)
Keyrigger HF Scale Support Join Date: Jan 2010	I'm sure others will have some thoughts, too, but my personal preference is to keep a multi-blade at around 2000 to 2200 with a three blade head maybe a bit higher at 2300. Most gearing is easily accommodated with motors from 2400 right up to 3400 to give you head speeds at that level. You really need to look for an online or downloadable calculator (Mr, Mell's is a good one) and plug in a motor with your main gear and pinion options. Even I was surprised that a 3400 could be tamed to that level and with a governor capable ESC, you can set it and forget it. Who knew? Hope this helps. Don

02-09-2014, 01:22 AM	#3 (permalink)
bdfox1 Registered Users Join Date: Jun 2012	Don's advice is pretty much right on from what I can find out. I have just finished a 450 scale heli with a 3 blade head. I am running a 2900 KV motor with 11T pinion, 121 T main gear on 3S. My head is a CopterX rigid one and I am using their very inexpensive molded blades. I am using the latest Align tail blades that are 68 mm long. I easily get off the ground with even 2250 with the fuselage on it. But I feel like it likes 2300 better withthat extra weight. I have an additional load on it with a water tank and pump and it does get off the ground fine on 2300 but I think it feels better at 2350. But not many hops in yet to verify that. But what that says is that these are the target ranges to be fooling around in. Not 3400!!! As soon as it warms up a bit (hopefully next week) I can maybe get out to try some more experiments in settings and might find that I can cut it back again. Bags of fun. -Barry

02-13-2014, 02:29 PM	#4 (permalink)
bdfox1 Registered Users Join Date: Jun 2012	So throw out all those comments I made. Now that I have my pitch curve in the ballpark (well closer at least) I find that I am down to 2250 and it flies just fine. So the next exercise is to move all the governor settings down again and try it even lower. I have hunch that lower isn't going to be much lower as I can see just the slightest little tail wag at times so maybe the tail speed is getting to where it won't hold. But maybe a little gain change will fix that too. It really isn't much. Might end up being a slight gyro setting change as well. The only thing I find with the lowest RPM so far is that my efficiency is dropping off a touch and the current draw and temps are going up just a little. I ran the numbers through the calculator on the ESC software and dropping the KV on the motor by 200 (because I can find a motor at that speed) and then gearing the pinion up one tooth I can get the same head speed and a 5% bump in efficiency back into the low 90% range. That should help bring the temp back down. Lots of fun experimenting. -Barry

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