electric clutches

[RotoPlane]

Vance:
The max continuous pressure for those .7 cu.in motor/pump is 1500 psi.

---Just some quick figuring---

(180 x 12) / 1.5 = 1440 Motor rpm
(.7 x 1500) / 6.2832 = 167.11 in.lb Torque
(167.11 x 1440) / 63025 = 3.82 Motor HP

That 30' rotor will most likely have more than 3.82 HP in drag….even at only 180 rotor rpm.
I think you will find it to be anemic at best , unless you go over the recommended pressure.

To heck with the funding interruption….I want to see your creation flying!

 

[Vance]

Our thoughts

Our thoughts

Hello Ed,

We feel confident that the .7 cubic inch pump/motor will operate at 2,000 psi and 3,000 rpm for the time frame of the prerotation.

At 2,000psi the motor will produce 222 inch (18.5 foot pounds) of torque.

At 3,000 rpm that would be 18.5X3,000/5252=10.6 horsepower.

We feel that 10.6 horsepower will be enough to get the 30 foot 8.5 inch chord rotor to 150 RPM.

We are not trying to make something that will last 10,000 hours so we feel we can run on the high side of things.

Plan B is to go to a larger pump. The .7 cubic inch motor is rated at 18.5 foot pounds X 5,000rpm/5252=17.6 horsepower.

Plan C is to go to a larger pump and motor.

We feel the 1.8 cubic inch Cross pump that still weighs less than seven pounds can produce 840 inch pounds (70 foot pounds) at 3,000 psi. At 3,000 rpm we feel it would produce 40 horsepower. The pump is rated for 3000psi and 3,000 rpm continuous.

Any of this is dramatically better than the Toyota starter on The Predator.

Thank you, Vance

 

[themonarch]

Pre-rotators. Hydraulic. Electric.

Pre-rotators. Hydraulic. Electric.

Hydraulic driven pre rotators are an excepted method. By reading this post, it seems that there are desires for enhancemant. This a good thing. May I ask all of you for your opinion of the alternative, that being electrically powered pre rotators?

Larry Neal is nearing his release to the public of an new design electric powered pre rotator system. Mr. Neal states that his latest system will spin to flight rpm. Thats how he put it to me in a recent email. I could have asked Larry with more detailed and specific questions about his system, yet have decided to wait and view the merchandise.

Someone at Mentone stated that he could be using an electric motor as seen on scooters. I did not know that there were electrically driven scooters. I am curious. Would the any reader here bother to shed some light on this concept as applied to pre rotators?

Thank you for your input. MJD.

 

[RotoPlane]

I'll admit Vance, that I tend to lean on the conservative side and usually follow the engineers recommendations, but those sealing areas may last long enough to be a counted a success….worth a try.

I am curious about how you have the motor running at 3000 rpm….are you using a gearbox or extra sprockets?

By the way, perhaps they have improved, but we used hundreds of Cross gear pumps and motors one year and they lost gobs of efficiency after about four months use. We had better luck with Tyrone gear units….although I am not a fan of any gear motors or pumps. Now piston units turn me on .

 

[Vance]

A small planetary gearbox of dubious ancestry.

A small planetary gearbox of dubious ancestry.

I am curious about how you have the motor running at 3000 rpm….are you using a gearbox or extra sprockets? .

Hello Ed,

We found a 1.6 to one planetary gear box that goes under the bendix with a 9 tooth pinion running against a 108 tooth ring gear. The planetary gearbox appears to be off a large drill and has an aluminum case.

I have that as 265 foot pounds of torque even at the lower 1,500psi or 355 foot pounds at 2,000psi.

The pump will be overdriven 1 to 2.1 with a V belt to the electric clutch.

We prefer the Parker pump.

Thank you, Vance

 

[RotoPlane]

Ah so....good idea. Thank you Vance!

 

[WHY]

Hi Martin

While not extremely popular here in the States, in Asia and Europe electric scooters and electric bikes are very popular. Have an electric bike my self with the "hub motor" on the bike, VERY HAPPY WITH IT.

I am very glad to see this thread gather so much attention from people with experience in both fields, hydrualic and electric. I feel that both systems are very practical, it just depends more on the machine as to which one is the choice.

My ambition is to see takeoff runs in the 300 ft range as an everyday takeoff and 200 ft as "special" . If our sport is going to become truly competitive with other types of aircraft, we have got to start "walking our talk" and we are always "talking short takeoff and landing, well, we got half of it .

Tony

 

[WHY]

Just a side comment, those interested in the hydrualic style pre-rotor, RotoPlane in post # 17 gave a really good source for the electric clutches.

Tony

 

[Vance]

A fun prerotator motor

A fun prerotator motor

Technical Specifications:
Motor Diameter: 3-1/2"
Shaft Diameter: 8mm
KV: 130 Kv
Voltage Range: 37V
Max Amperage: 90 Amps

Weight: 48 oz.

Maybe something like this would make a fun prerotator motor.

You could use two and still be lighter than most electirc starters.

A small batter pack would run it until you could charge them back up.

Thank you, Vance

 

[WHY]

Check out possible E-bay buy, on Ogura clutch E-bay # 230820046001 $85

Tony

 

[CLS447]

Ercoupe and Cessna 150, 152, 172, 140, Aeronca,7ac, Citabria,Chief,Piper PA11,PA12


Tony, do you own all of these now ? Do you have a flying gyro now ?

Just curious ?

 

[WHY]

Hi Chris,

Just owned the Ercoupe and Cessna 150, sold the Ercoupe a few years ago. Soloed the rest. Building a tractor gyro.

Tony

 

[Alan_Cheatham]

Hydraulic driven pre rotators are an excepted method. By reading this post, it seems that there are desires for enhancemant. This a good thing. May I ask all of you for your opinion of the alternative, that being electrically powered pre rotators?

Larry Neal is nearing his release to the public of an new design electric powered pre rotator system. Mr. Neal states that his latest system will spin to flight rpm. Thats how he put it to me in a recent email. I could have asked Larry with more detailed and specific questions about his system, yet have decided to wait and view the merchandise.

Someone at Mentone stated that he could be using an electric motor as seen on scooters. I did not know that there were electrically driven scooters. I am curious. Would the any reader here bother to shed some light on this concept as applied to pre rotators?

I've seen Larry's system and he's using the newer breed of electric motors, controllers and Lithium batteries, with this you can put 20 hp to the rotor and that will get you to flight rpm. This is far more hp than your typical electric starter motor prerotator can deliver and gives far greater performance but also comes with it's own set of pros and cons, mainly cost, durability and risks of Lithium batteries.

For detailed information on Larry's system I defer to Larry, when he's ready.

.

 

[cbonnerup]

Technical Specifications:
Motor Diameter: 3-1/2"
Shaft Diameter: 8mm
KV: 130 Kv
Voltage Range: 37V
Max Amperage: 90 Amps

Weight: 48 oz.

Maybe something like this would make a fun prerotator motor.

You could use two and still be lighter than most electirc starters.

A small batter pack would run it until you could charge them back up.

Thank you, Vance

VERY NICE Vance,
2 would give you almost 9 HP. Do you happen to know what the 130 KV is referring to?

The main 'problem' with MOST current electric motors is that they 'like' to run at full power or not at all unless the controller is wasting a lot of the power. This means you have to switch the power off / on (called pulse-width-modulation) at very high speed to control motor torque below rated max. Rapid switching of high currents produces nasty side effects on other electronics nearby. It can be designed out by careful design, but IMHO is not an easy or cheap task. Poly-phase (3 or greater) motors are better controlled in this manner.
There are some unique designs of electric motors in the works, and we will see if someone can offer a 12V (or 24V) motor at 10 HP output; that would be 625 (or 312) amps at max HP. The key to high power small motors is operating at high voltage and low current; but high voltage presents other problems. Again not impossible; these issues can and will be worked out.

When 'they' develop room-temp superconducting wire it will make fusion power unnecessary - at least for a while.

Regards,
Chris

 

[Vance]

A different sort of prerotator

A different sort of prerotator

VERY NICE Vance,
2 would give you almost 9 HP. Do you happen to know what the 130 KV is referring to?

Chris

KV=Rpm/V

This particular one is 37 volts and uses a controller something like this one.

Technical Specifications:
PHOENIX ICE2 HV 160 Specs:
• Length: 3.99" (99mm)
• Width: 1.5" (38.1mm)
• Height: .9" (22.9mm)
• Weight: 2.3 oz* (65.2g)*
• Max amps: 160 amps**
• Max volts: 50 volts,12s LiPo,36 cells NiCad/NiMh

It can be driven by less than two pounds of Lithium Polymer batteries.

I suspect that two would probably drive a 30 foot rotor to 150 rpm.

The even come with little gearboxes if you want or plug them into a car starter bendix and gearbox..

Thank you, Vance

 

[WHY]

The voltage/current thing is the present nemisis of the electric pre-rotor for larger rotors, so for larger rotors, it is mainly going to be hydrualic or mechanical. 12 volt electric is still a good option though for the smaller rotors, I think it can easily reach the 200 to 250 rpm range. We just need to stir up the minds and imaginations of the guys "in the basement and out in the garage" !!! Just look what has come up in this thread in the last week or so

Tony

Tony

 

[robhodgman]

Vance, what did you end up going with? Electric or hydraulic? I am having a heck of a time with the prerotator in my Sparrowhawk and am looking for a better solution.

Thx, Rob

 

[Vance]

This thread is from 2012.

Mariah Gale that was the subject of my posts was still born Rob.

I have over 2,000 hours on The Predator with eight and a half inch chord 30 foot Sport Rotors.

She uses a Denso geared starter off a Toyota.

On a good day in still air I might see 100 rotor rpm.

I believe I am on starter number five and ring gear number three.

The voltage drops below the radio voltage threshold so the radio doesn’t work when the pre-rotator is engaged.

I have lots of time in modified RAFs and Sparrow Hawks and I felt their system was much better as long as I didn’t overheat it.

It was not hard to see 160 rotor rpm and I feel two hundred was possible.

Good luck on your gyroplane adventure.

 

[robhodgman]

This thread is from 2012.

Mariah Gale that was the subject of my posts was still born Rob.

I have over 2,000 hours on The Predator with eight and a half inch chord 30 foot Sport Rotors.

She uses a Denso geared starter off a Toyota.

On a good day in still air I might see 100 rotor rpm.

I believe I am on starter number five and ring gear number three.

The voltage drops below the radio voltage threshold so the radio doesn’t work when the pre-rotator is engaged.

I have lots of time in modified RAFs and Sparrow Hawks and I felt their system was much better as long as I didn’t overheat it.

It was not hard to see 160 rotor rpm and I feel two hundred was possible.

Good luck on your gyroplane adventure.

Vance , so sorry to hear about Mariah.

Thanks for your input, I prefer the electric prerotator over hydraulic, for simplicity and weight. I will continue to move in this direction; would love to hear from others on their experiences with electric and hydraulic prerotators.

Vance, when you have time could you send me close-up photos of your setup?

Thanks
Rob

 

[Vance]

Good Morning Rob,

Here is a picture of The Predator’s Denso geared starter from a Toyota.
I am down at the hangar and my log book says I am on starter number five and ring gear number three in 2,071 hours.

I have logged 2,672 landings: lots of the takeoffs are stop and goes so I an not using the pre-rotator.

100 rotor rpm in still air with 30 foot eight and a half chord Sport Rotors.

The radio doesn’t work when I am pre-rotating because the voltage drops below eight volts.

I would stick with the flexible drive and clutch you have now.

People who have worked on their RAF or Sparrow Hawk pre-rotators have regularly seen 200 rotor rpm with 30 foot blades.

The flexible cable is still available as is the bendix and ring gear.

The clutch is not hard to repair if it has been warped and overheated and the pads are easy to replace.