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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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.
 

Smack

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

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.
 

All_In

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Not sure over 10,000+ logged FW, 260+ ultralights, sailplane, hang-gliders
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.
 

ultracruiser41

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I agree with Vance.....lots of starts and short flights with no issues. I even run the same Odyssey battery.
Only issue is every 3 or so years....I replace the starter.......always have a spare on the shelf.....just bought 2 for $50 each.
 

NoWingsAttached

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Hmm. I had an Odyssey fail after only a year, big waste of my $$$.

On the other hand, I have had half a dozen Yamaha batteries that weigh about the same as the Odyssey did, about same size, like motorcycle battery style, and these batteries all sat around for the better part of the year in their past lives w/o getting a charge over the summer months and here some of them are still on my shelf, or in gyros, up to 15 years old and still cranking 150HP YG4 gyro motors with plenty of juice.

Now THAT'S a battery.

Thing is, I just don't know if it has enough amp hours to spin the big tandem rotors up or not. Geoff had an Interstate auto battery on it, I'm thinking I need something the same size, which is 7 x 10 x 6.5
 

Vance

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My Odyssey Battery is warrantied for two years by EnerSys.

At twenty three months they replaced it free of charge when it failed the high rate discharge test even though it would still start the Lycoming and pre-rotate to a hundred rotor rpm.

I have a battery tender specifically set up for the Odyssey battery.

I have had good luck with Odyssey batteries and am on battery number three in ten years.

I have the battery laying on its side at the bottom of the rotor tower.

I like being able to mount the battery in any position.
 

wolfy

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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.
Sounds like a very interesting set up are they available yet?

Thanks Jim
 

wolfy

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here is my prerotator ... I did not test it yet... I cross fingers :



I have to cut the 4 tubes short by 5mm to put the two gears at the same level, and also to install a small shaft at the top of the leading gear ending in a small ball bearing to conteract the lateral ejection force that the small gear will get

I have designed it making it possible to move latteraly the brushless in order to fine tube to gear position and also to change the gear ratio

it is an 8000W 168 kv 56V brushless, I kept the bendix of the averso rotor head, total gear ratio is 24:1, voltage of the lipo pack under max load should fall to 45v giving a brushless rpm of 7400 rpm (without rotor of course) ... it should get my rotor to my usual 240 rpm with no problem if I refer to what a friend of mine ( an engineer has calculated) ... tests late nex year...

the pack is 2.6 kilos and the whole system weigth 4 kilos ... I have weigthed a full magni solf cable system ( all included) .. 11 kilos but I won't charge in fligth and will only be able to make say 6 pre spininning in the day ... if it work aotherwise I will have spent 900 euros for nothing hahaha
Interesting mate have you had a chance to do any testing yet?

wolfy
 
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