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PerEklund  
#121 Posted : Friday, August 5, 2016 11:55:54 AM(UTC)
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And does a rpm limiter require a rule change. If it for instance is built in in the ignition?
I'm not after a constant speed solution. I would like a pure limiter.

--Per
Offline Gil R. Major  
#122 Posted : Saturday, August 6, 2016 7:34:38 AM(UTC)
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Originally Posted by: Steve Stanton Go to Quoted Post
Seems like it would be easier to do this electronically on RC controlled planes. Question is: would this require a rule change?


Originally Posted by: Per Eklund Go to Quoted Post
And does a rpm limiter require a rule change. If it for instance is built in in the ignition?
I'm not after a constant speed solution. I would like a pure limiter.

--Per


To require a rule change you would be wanting to change something which already exist. Is there something in the rules preventing a constant speed prop whether controlled mechanically or electronically? NO!

4.3: There shall be no airborne devices fitted to the aircraft which place the aircraft under less than total control by the pilot. These devices will include, but are not limited to, gyros, automatic pilots, electronic stabilization, and timing devices. Non-airborne aids such as transmitter based functions are permissible.
Pilots found to be using prohibited devices will be disqualified from the contest.

This rule concerns control of the flying surfaces / flight controls.

What change is required?
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PerEklund  
#123 Posted : Saturday, August 6, 2016 11:51:49 AM(UTC)
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I thought it might be in the gray zoone, but I agree with you it must be ok to use.
Thanks a lot for your input.

--Per
Offline RyanW  
#124 Posted : Sunday, October 23, 2016 9:13:01 PM(UTC)
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Originally Posted by: Ron Graham Go to Quoted Post
prop governor.jpg (10kb) downloaded 13 time(s).

Any speculation on what a miniature version would cost to develop?? Crying
Maybe somebody could get DA to chime in???


This would be super easy to do. We have done this for decades with r/c helicopters. Simple rev limiter about the size of a postage stamp. Small optical, hall effect or ignition wire sensor to get rpm and you are done.

BTW... they have RPM limits on the RedBull air race planes. It is *interesting* how some of the pilots try to cheat the system.
Offline kjetilmh  
#125 Posted : Thursday, May 10, 2018 11:59:34 AM(UTC)
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Hi folks

Our flying field has a problem with sound sensitive neighbors.
Over the last coupe of years we have done a lot of measurements.
All of us to fly gas , but now most of us is on electric.

The neighbors was very happy with this. The electric planes was less annoying.
The strange thing is that when we did measured the sound ( following the guidelines ),
there where only minor differences in the DBa level.

Thus:
- Most of the noise from our planes are from the propeller.
- The sounde from an gas engine is more annoying, that electric even on the same nose levels.

During our work we have also compared different electric configuration.
We have discovered that in order to reduce the noise levels , it is wise to :
- Choose a 3 blade propeller.
- Choose a big propeller.
This prop needs to spin at a low RPM. Thus you will need a Low Kv engine.
The propeller also needs to be high in pitch.

One one occasion a 2 blade 26x15 was replaced by a 3 blade 30x16.
This is on a 2.6m Krill Yak. The 3 blade propeller is spinning at approx 4200 rpm (on the ground).
The measured sound level was down by 7 DBa. That is a significant reduction.

Kjetil





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