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HelicopterScale Model RC Helicopters › Heed Speed ?
04-09-2011 08:27 PM  6 years agoPost 1
mcfast

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Quebec Quebec Canada

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Looking in bilding a complet Scale 500 size MD500E.
What would be a good head speed for a scale 5 blade head ? and what blade size ?

P.S. sorry for the spelling or the grammar I am dyslexic!

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04-09-2011 10:01 PM  6 years agoPost 2
DrRotor

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Auckland New Zealand

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Hi.

Use TF model scale blades. These will help dampen the rotor head. I have not clocked any of my 5 blade heads so I cannot say for sure what the head speed is. I fly by feel, sound and sight and adjust parameters untill everything is going smoothly. I know how I want my helis to handel and feel so I adjust them untill they fly how I want them to.

If I were to take a stab in the dark Id say about 1500-1700rpm on a 500 size machine. Depending on blades as the TF model blades are flat bottom and create a little more lift so they dont need to turn as fast and the pitch range is -2 to +5 deg.

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04-09-2011 10:25 PM  6 years agoPost 3
mcfast

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Quebec Quebec Canada

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Sounds good !

Thanks

P.S. sorry for the spelling or the grammar I am dyslexic!

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04-10-2011 05:18 PM  6 years agoPost 4
Copter Doctor

rrProfessor

Enterprise/ft.rucker​,al- home of army​aviation

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I fly by feel, sound and sight and adjust parameters untill everything is going smoothly. I know how I want my helis to handel and feel so I adjust them untill they fly how I want them to.
our habbits are one in the same.
these days folks ask me questions i find hard to answer ie what head speed and what pitch settings etc

drive a rotary, fly a rotorcraft

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04-10-2011 05:56 PM  6 years agoPost 5
helibeli

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wales.uk

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Is there a formula to use to calculate optimum speed for a given rotor diameter?

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04-10-2011 07:08 PM  6 years agoPost 6
mcfast

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Quebec Quebec Canada

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And what blade size ?

P.S. sorry for the spelling or the grammar I am dyslexic!

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04-10-2011 11:01 PM  6 years agoPost 7
DrRotor

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Auckland New Zealand

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our habbits are one in the same.
these days folks ask me questions i find hard to answer ie what head speed and what pitch settings etc
Thats great to hear, I thought everyone these days was into all this calculating head speed stuff. Nice to know Im not the only one that flys this way. I see you also state something about driving a rotary in your signature. Do you own a rotary car Copter Doctor?
Is there a formula to use to calculate optimum speed for a given rotor diameter?
I dont know Helibeli.
And what blade size ?
If you buy the TF model blades you will not need to worry about blade size. Here take a look. They are not expensive.
http://www.smartmodel.com.hk/produc...80&third_id=157

I think the main cause of all this head speed talk is that alot of people do not know how to setup a throttle curve to create the head speed you want. Everyone seems to gear their machines down to generate a head speed at 100% throttle. I dont see the need for this. Since govenors came about the art of throttle curve went out the window. Dont get me wrong I think a govenor is great but you dont need to rely on it.

Here is an example. Since I posted on here in regards to my scale project the no1 thing has been what is your gear ratio and have you calculated your head speed. Well I tell you what, I went to check out this head speed calculator and put in all the parameters and got a head speed of 2400rpm at 100% throttle. Ofcourse this is way to fast, anyone can see that but you dont need to go and buy a nother main gear to drop the speed. Please do take into account that the head speed will drop when under load. Anyway at 50% it should be 1200. So this tells me I need to be starting off with a throttle curve that runs up into the 75% range where the head speed will be around 1800. Add in some pitch on near flat bottom airfoil blades and the speed will drop to probly around 1700 or so. BUT wait, this is a big bird and could potentialy be quite heavey, so It would be smart to have that extra bit of grunt above 75% throttle to get you out of the ****.

Do be aware that the govenor will not work below 50% throttle so make sure that your desired head speed if you are one to calculate is above 50%.

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04-12-2011 09:48 PM  6 years agoPost 8
MaxPilot57

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Dothan, Al. USA

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04-12-2011 10:20 PM  6 years agoPost 9
mcfast

rrKey Veteran

Quebec Quebec Canada

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Boy thoes are long ! ?

P.S. sorry for the spelling or the grammar I am dyslexic!

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04-12-2011 11:00 PM  6 years agoPost 10
Copter Doctor

rrProfessor

Enterprise/ft.rucker​,al- home of army​aviation

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I see you also state something about driving a rotary in your signature. Do you own a rotary car Copter Doctor?
yep, i have a NA Mazda RX-7. 13B rotary engine

drive a rotary, fly a rotorcraft

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04-13-2011 02:06 AM  6 years agoPost 11
DrRotor

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Auckland New Zealand

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yep, i have a NA Mazda RX-7. 13B rotary engine
Exelant, I also have an RX7. FD3S 13B-REW. Ill PM you a pic if you want to see it.

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04-13-2011 06:15 AM  6 years agoPost 12
Copter Doctor

rrProfessor

Enterprise/ft.rucker​,al- home of army​aviation

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yes, would love to!

drive a rotary, fly a rotorcraft

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04-13-2011 07:36 PM  6 years agoPost 13
MaxPilot57

rrApprentice

Dothan, Al. USA

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Boy thoes are long ! ?
Same size as the stock 500 blades.
And shipped from the US should get them to you quicker and less expensive.

Wayne

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