Electric Pre-Rotator

All_In

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Thank you Vance any information regarding current rating etc., would be helpful.



All-In, thank you, a lot of interesting information, just need some time to digest. Where do I send a donation to the research? Thanks to all for responding so far I'll get back when I have more time.
Wow, you rock! I wrote most of the page for Open Source Project last night. It will have the current status and a donation page.

It needs its own revenue source to be self-sustaining as it's a 5K sponsorship fee that the 1st 3 projects waved they wanted the projects but we have to pay for parts.

So my new thinking is:
We will sell the SolidWorks plans and CNC code etc "For Educational Purposes Only" assuring our team and PRA has no liability.
We will pay S.D.U. back for our 1st project out this revenue, the car-starter project, that is in testing, earns for itself.
But the pricing will be based on the complexity of the and number of components/drawings, CNC or software code.
From $50 to $250 for the Jump-takeoff plans being the most complex, with PRA members benefit of 50% off.
Might aks for a DONATION but as a pre-pay purchase = when it is finished it would be free to those you pay in advance,
Let people vote for the project they want with their wallets to help fund it at first to make it happen sooner rather than later.


I need to get this new source of revenue voted on by the board before I post much more and it may change...
 

Skyjinks

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Wow, you rock! I wrote most of the page for Open Source Project last night. It will have the current status and a donation page.

It needs its own revenue source to be self-sustaining as it's a 5K sponsorship fee that the 1st 3 projects waved they wanted the projects but we have to pay for parts.

So my new thinking is:
We will sell the SolidWorks plans and CNC code etc "For Educational Purposes Only" assuring our team and PRA has no liability.
We will pay S.D.U. back for our 1st project out this revenue, the car-starter project, that is in testing, earns for itself.
But the pricing will be based on the complexity of the and number of components/drawings, CNC or software code.
From $50 to $250 for the Jump-takeoff plans being the most complex, with PRA members benefit of 50% off.
Might aks for a DONATION but as a pre-pay purchase = when it is finished it would be free to those you pay in advance,
Let people vote for the project they want with their wallets to help fund it at first to make it happen sooner rather than later.


I need to get this new source of revenue voted on by the board before I post much more and it may change...
All_in, Thank you for the further information/update, I look forward to hearing more. Regards
Skyjinks.
 

Jazzenjohn

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I've designed, built, and flown 4 different ultralight gyros. Amassing parts for a 2 place now.
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Wolverine, That Amp Flow motor is a Beast of a motor, but neither the little Kobalt Battery, nor the speed control you're using are up to the task of driving it to its full potential. You'd need to go to a battery capable of 36 volts and supplying a minimum of 200 amps burst to get the full power out of it and to see anything near 220 RPM, and a speed control that can handle at least that. I probably wouldn't look at an ESC that wasn't rated at 300+ amps for 30 seconds and at 48-50 volts for 36 volt operation.
 

jm-urbani

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this Guy did the job, there is no detail as for the RPM , number of prerotations possible, batt pack etc, but is seems to work..
I should not have placed the batt pack behind the head of the pilot and against to mast but it is one more evidence that brushless RC engines are ok for the job what do you think ?
 

jm-urbani

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what we usually hear about electric prerotators is "if it could work it would already exist"
there is nothing less true ... we all know that in Aviation everybody wants to build something that has already been tested...

first of all there are people who have done the job :


and secondly it is not impossible to try...

I have had the chance of accessing to some calculations proposed by a well known engineer envolved in gyroplane in France ( I don't quote hime coz his advices were private)

in order to sum up he was saying that in order to pre spin an averso heavy 8meter 8h12 rotor at 200 rpm it would require 3400 w of electric power and 2500 of mechanic power ( he has calculated all the gear and other losses)

he says that using 2 5000mA lipo packs the or better 4 packs the internal resistance would bring down the voltage to 36v ( 2 pack in serie) and to 45v ( 2 pack, 2 S et 2 P) it would be really safe and easy (in terms of energy storage) to get multiple pre-rotations on only of recharge.

using a 200 A controller, a 8000w brushless and limiting to reprotation to say a max of 240 RPM it should be possible to stay away of the mechanical and electrical limits ...

I have not much choice then trying this cos I don't want to build an other mechanical pre rotator that would fit my mast and cheek plate géometry

the only technical issue I am afraid of when I fly is this mechanical link btw the engine and the rotor

we have a friend who's trainee has triggered the pre rotator in flight , the rigid shaft has bent making it impossible to pull the stick backward , they hit the ground nose first and were seriously wounded ... from this date I promised myself to search for an other solution
if I manage to pre spin 4 time in the day at 220 rpm it would be great and enough


with a 8000w turnigy brush-less, a 200A controller and 4 5000 mA lipo I thing it will be possible... maybe ... hahahaha

750 euros .... for all the hardware ... I hope it will work hahaha
 
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Smack

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A pre-rotator that is independent of the engine would be great !
More power ! ;)
 

jm-urbani

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to be honest the more powerful thing on a gyroplane is it's internal combustion engine ....
 

jm-urbani

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Yeeeesssss ! goooodddd I like those who speak less then what they do (unlike me) .... IMHO you reached 200rpm
how did you controlled the motor acceleration ? manually or via a micro controller ?
 

Jazzenjohn

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I've designed, built, and flown 4 different ultralight gyros. Amassing parts for a 2 place now.
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That video was 3 years ago. At that time I used a knob for control. Now I have 3 buttons and a micro controller. off/reset, Idle, where it takes it from a few RPM to idle speed of 65 RRPM, and fly, taking it from idle to full RRPM. I've seen 215 RRPM peak but it pulls past that. I use between 375-500 milliamp hours for a complete spin up. idle, taxi at idle, and full prerotation, so, between 6 and 10 full prerotations for the batteries I use. I'm working with Denis at Gyrotechnic to fit it to his rotorhead. After I do that I'll work on fitting it to existing Wunderlich heads.
 

jm-urbani

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Awesome, and encouraging for me even if Averso rotors are heavier then yours and even if I have a 8.4 m rotor (longer then yours)
it is a good idea to use a microntroller to drive the acceleration,
I am not able to calculate inertia forces and then drag forces coz I am too stupid for this , but the engineer that had let me know the details of his pre-spinner project was saying that after having overcome the intertia forces accelerating slowly not to brake everything we ought to accelerate more not to ask the engine to work aginst the drag for too long
so it is important to enter all the acceleration curve into a microcontroler to reduce to engine time and get more prerotations from the same pack btw 2 charging sessions...
thanks a lot for sharing really
 

All_In

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All the parts are in the student's hands for this project. Expect to test in 60 days or less. I will let you know.
 

JETLAG03

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Wow that really does sound interesting. Will the plans and parts list be made available or will you be selling the full kit ?? Either way any idea on price range and availability ??

regards

phil
 

All_In

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Not sure over 10,000+ logged FW, 260+ ultralights, sailplane, hang-gliders
Wow that really does sound interesting. Will the plans and parts list be made available or will you be selling the full kit ?? Either way any idea on price range and availability ??

regards

phil
Liability in the US prohibits PRA and or the students from selling finished products. We can buy motors, controllers, etc in volume and keep them in inventory for our community passing on the savings.
We can sell Solid Works drawing as plans including the software, CNC code, parts list, and instructions. That is what PRA requested as a final product.
We also hope a Chapter or manufacture will produce the machined parts for sale.
The board has not set a final price. I expect $25,00 to $50.00 for everything.
 

All_In

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Not sure over 10,000+ logged FW, 260+ ultralights, sailplane, hang-gliders
PRA will be selling battery packs in custom dimensions to fit odd-shaped spaces, battery management systems, and charging controllers for all of the new projects in the works.
Currently, we are working with two colleges, 3 professors, on 7 new projects with about 40 students.
 

NoWingsAttached

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I use a geared Denso starter off of a Toyota for a pre-rotator on The Predator with her thirty foot eight and a half inch chord Sport Rotors.
Then:

I do not recommend a car starter for a pre-rotator. It is my understanding their duty cycle is six seconds and they make a lot of heat.
I always thought of Toyota as being a car/truck manufacturer...what am i missing here?
 

NoWingsAttached

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I am shopping for a battery for a customer's electric pre-ro system (rotor is 28' or 30'). Thanks, any helpful hints from Heloise? Need it pretty quick, the project is winding down and nearly ready to test fly the first anywhere Yamaha 165HP titanium EXUP valved exhaust. geeked.
 

Vance

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Then:



I always thought of Toyota as being a car/truck manufacturer...what am i missing here?
My experience with various pre-rotator systems has taught me that an automobile starter may not be the best choice.

The Predator uses an automobile starter and it works well enough to not go to the trouble of using a better system.

It typically reaches 100 rotor rpm without wind assist; more rotor rpm would be easier for my clients to learn.

The modified starter that I described in the post that would reach 120 rotor rpm wore out the ring gear.

Operating the pre-rotator drops the voltage low enough (less than eight volts) to where the radio doesn’t work while I am pre-rotating.
 

Vance

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I am shopping for a battery for a customer's electric pre-ro system (rotor is 28' or 30'). Thanks, any helpful hints from Heloise? Need it pretty quick, the project is winding down and nearly ready to test fly the first anywhere Yamaha 165HP titanium EXUP valved exhaust. geeked.
From post ten:
I use a an Odyssey PC 680 and in one very busy day I started the 320 cubic inch Lycoming engine and the rotor 45 times. Most of the flights were less than fifteen minutes so there was not much time for the battery to recharge.
 
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