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HelicopterAerial Photography and Video › Main blade attack angle?
11-06-2013 04:59 PM  4 years agoPost 1
Helicek

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istanbul - turkey

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Hi folks,
it is about the 80cm symmetrical Align main blades I have on my AP ship. It hovers spinning around 1,200rpm with 5°/6° of pitch where vibration appears (feels) to be minimum and I am happy operating it this way.

Lately, the AUW increased 1kg. To have the heli hovering like it did the lifting force has to be increased. I can either raise the pitch and keep rpm same, or raise rpm and keep pitch, or both.

Well, this is the scenario. What is too much pitch? Is there a way to figure out the optimum pitch range where drag is reasonable for a particular blade?

Cheers,
Ahmet

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11-06-2013 06:01 PM  4 years agoPost 2
JKos

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Redondo Beach, CA

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Is there a way to figure out the optimum pitch range where drag is reasonable for a particular blade?
Sure. Do you have any way to collect current/power data from your power system? Try both methods and see which one requires the least power to hover.

You could test every 25 or 50 RPM over your available RPM range and determine the optimum RPM for you setup.

- John

RR rules!

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11-06-2013 07:39 PM  4 years agoPost 3
Helicek

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istanbul - turkey

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Hi JKos,
Do you have any way to collect current/power data from your power system?
Yes, I do have live main power supply current and voltage telemetry display. Sometimes things get confusing and I would like to stay on the efficient zone as far as pitch angles go.

Thanks,
Ahmet

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11-06-2013 10:47 PM  4 years agoPost 4
bigwolf1

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USA

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Sounds like a heli set up. I don't know any what but you might try this.

http://www.ecalc.ch/helicalc.htm?ecalc&lang=en

I'd try to increase RPM to take out vibes low rotor speeds will develop some vibes. OR get some wider cord mains to give better lift and lower pitch settings. The old V blades would hover around 5 deg. maybe some of the G5 pro's also.

Just a thought.

MAH blade Rep
Trex700LE
Magnum fuels

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11-07-2013 03:46 AM  4 years agoPost 5
Stephen Born

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USA

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Ahmet,

Your AP ship has considerably more weight to it than an average heli.

If you do not have enough pitch, you will have difficulty with autorotations. The is especially true when accompanied by low head speeds.

Weight + low HS + minimum angle of attack = hard landing.

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11-07-2013 09:26 AM  4 years agoPost 6
Helicek

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istanbul - turkey

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Thanks all.
Like you all noted there are many variables and parameters involved getting the AP heli flying properly.

When the heli does not take off we increase RPM we may get vibs. We slow RPM increase pitch then tail can not cope and SAS won't like it either. If I knew more about the the blades flying properties then I would choose the ones suits my flying the most.

It is either rotor head, main blades, motor, esc, LiPos, camera mount, camera, SAS and/or others that need careful setting and matching to get things working in harmony. This is obviously going to take a lot of time and effort.

Anyone tried and liked the SpinBlades 710H?

And yes, I know I need to increase the head speed

Talk to you later,
Ahmet

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11-07-2013 10:24 PM  4 years agoPost 7
Anto6ka

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Chisinau, Moldova

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I run our 800 AP ship at around 1650 RPM. Feels smooth, predictable, and does not bog at high speeds, high winds or any maneuvers. You migh consider trying raising your HS, just to see if it would suit you. Harmonic vibes come and go every 200-300 RPMs in my experience.

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