Hydraulic Pre-Rotator specification!
- Thread starter sadegh_865
- Start date
Mike G
Junior Member
- Joined
- Jun 16, 2005
- Messages
- 1,918
- Location
- Lillebonne France
- Aircraft
- Owned Magni M16 now ELA 07
- Total Flight Time
- 550FW + 500 gyro
ROTORTEC
Is that you Michael?
Put it on youtube, everyone can see it with no problem.
Mike G
Is that you Michael?
Put it on youtube, everyone can see it with no problem.
Mike G
Link to Youtube
Link to Youtube
We have placed the Video on youtube for you now!!!
http://www.youtube.com/watch?v=dU3fcY-XWLk
John Steinbeck
Rotortec
Link to Youtube
We have placed the Video on youtube for you now!!!
http://www.youtube.com/watch?v=dU3fcY-XWLk
John Steinbeck
Rotortec
bones
Gold Member
- Joined
- Jul 28, 2004
- Messages
- 1,278
- Location
- Chtrs Twrs Australia
- Aircraft
- a/c
- Total Flight Time
- cant remember, didnt have log books before, but since over 3000
Is this a twin rotor system, it looks like it, but not sure?
Mike G
Junior Member
- Joined
- Jun 16, 2005
- Messages
- 1,918
- Location
- Lillebonne France
- Aircraft
- Owned Magni M16 now ELA 07
- Total Flight Time
- 550FW + 500 gyro
It does look like a twin rotor.
It also seems to have a flexible shaft drive, do you have any details of the pre rotator that you are prepared to share? 200 rpm is OK but nothing special, I take my old M16 up to 250 every time.
Mike G
It also seems to have a flexible shaft drive, do you have any details of the pre rotator that you are prepared to share? 200 rpm is OK but nothing special, I take my old M16 up to 250 every time.
Mike G
Mike G
Junior Member
- Joined
- Jun 16, 2005
- Messages
- 1,918
- Location
- Lillebonne France
- Aircraft
- Owned Magni M16 now ELA 07
- Total Flight Time
- 550FW + 500 gyro
John
How much detail are you prepared to give us, there's lots of interest???
Can you answer Sadegh's question "why did you choose hydraulic" I'd like to know as well.
Mike G
How much detail are you prepared to give us, there's lots of interest???
Can you answer Sadegh's question "why did you choose hydraulic" I'd like to know as well.
Mike G
Hydraulik Prerotator
Hydraulik Prerotator
Hydraulic Systems offer in my opinion the best value for the Job we have to do, getting the Rotor up to speed. In Hydraulic Systems, Motors run at low speeds with max Toque they supply. This is what we need to spin up a rotor system. Hydraulic Pumps can be switched on very easy by magnetic Clutch and for the short duration of need to run, the oil Volume can be very low. Valves allow a very soft engagement, and all the parts come in small size to. Overall imported for us is availability of standard low cost Industrial Items with the least moving parts. Hydraulics are used extensively in Aviation for more than 50 years, not we have invented this, been done forever. It is not easy to find the most effective parts, but worth wile to look out for them, to keep the weight to a minimum.
John
Hydraulik Prerotator
Hydraulic Systems offer in my opinion the best value for the Job we have to do, getting the Rotor up to speed. In Hydraulic Systems, Motors run at low speeds with max Toque they supply. This is what we need to spin up a rotor system. Hydraulic Pumps can be switched on very easy by magnetic Clutch and for the short duration of need to run, the oil Volume can be very low. Valves allow a very soft engagement, and all the parts come in small size to. Overall imported for us is availability of standard low cost Industrial Items with the least moving parts. Hydraulics are used extensively in Aviation for more than 50 years, not we have invented this, been done forever. It is not easy to find the most effective parts, but worth wile to look out for them, to keep the weight to a minimum.
John
Mike G
Junior Member
- Joined
- Jun 16, 2005
- Messages
- 1,918
- Location
- Lillebonne France
- Aircraft
- Owned Magni M16 now ELA 07
- Total Flight Time
- 550FW + 500 gyro
John
Thank you for the information.
Without giving away too many secrets, what sort of pump and motor are you using (gear, piston or other) and what pressures are you running at?
How about starting a new thread with some photos and data about your 4 bladed rotor, I'm sure there would be a lot of interest.
Mike G
Thank you for the information.
Without giving away too many secrets, what sort of pump and motor are you using (gear, piston or other) and what pressures are you running at?
How about starting a new thread with some photos and data about your 4 bladed rotor, I'm sure there would be a lot of interest.
Mike G
Hi Mike,
we use a alluminum Pump and a stock Motor form Danfoss. The pressure at pick is 220 Bar, Oil Volume of 1 liter total. If youlike to start a thread on 4 Blade rotors feel free to do so, has been done before here on this forum. I will post a new Video on Youtube with more close up shots of the Prerotator soon.
John
we use a alluminum Pump and a stock Motor form Danfoss. The pressure at pick is 220 Bar, Oil Volume of 1 liter total. If youlike to start a thread on 4 Blade rotors feel free to do so, has been done before here on this forum. I will post a new Video on Youtube with more close up shots of the Prerotator soon.
John
Mike G
Junior Member
- Joined
- Jun 16, 2005
- Messages
- 1,918
- Location
- Lillebonne France
- Aircraft
- Owned Magni M16 now ELA 07
- Total Flight Time
- 550FW + 500 gyro
Thanks John, I had a quick look at Danfoss, they have an extensive range of pumps and motors and at first glance seem better than the Parker pumps and motors, but I'd have to look in more detail to be sure. Are you using a gear pump and motor?
Mike G
Mike G
sadegh_865
Newbie
Hi dear friends
specially thanks Mike! and John.I think this thread is becoming so intresting by intering John ! WelCome John!
are u continuing by a new thread?
next days i will start to change my prerotator to a hyraulics one and some tests...
i 'll share my results....
Sadegh
specially thanks Mike! and John.I think this thread is becoming so intresting by intering John ! WelCome John!
are u continuing by a new thread?
next days i will start to change my prerotator to a hyraulics one and some tests...
i 'll share my results....
Sadegh
sadegh_865
Newbie
high performance parts!
high performance parts!
Hi
Mike & John, i've found a couple of hydraulic motor and pump with this specification:
motor:41kw,6000rpm
pump:34kw,3150rpm
ELA normal take off distance with it's prerotetor is under 100meter. in ur opinion, by these hydraulic parts installation,how much take off distance can we get? how prerotate RPM?
Sadegh
high performance parts!
Hi
Mike & John, i've found a couple of hydraulic motor and pump with this specification:
motor:41kw,6000rpm
pump:34kw,3150rpm
ELA normal take off distance with it's prerotetor is under 100meter. in ur opinion, by these hydraulic parts installation,how much take off distance can we get? how prerotate RPM?
Sadegh
Last edited:
Mike G
Junior Member
- Joined
- Jun 16, 2005
- Messages
- 1,918
- Location
- Lillebonne France
- Aircraft
- Owned Magni M16 now ELA 07
- Total Flight Time
- 550FW + 500 gyro
Sadegh
These seem very powerful but just to continue brainstorming, remember that your first problem will be the available gear ratio of bendix and ring gear. This is usually between 8 and 12 so if we say you want to pre rotate to 350 rpm your motor must deliver it's max power at about 3500 rpm. If your motor delivers 41 kW at 6000 rpm it will probably deliver half or less than half at 3500 rpm.
If it delivers say 20 kW, at a rotor rpm of 350 rpm that's about 545 Nm of torque at the rotor. If you pre rotate today to about 200 rpm that takes about 5 kW which is about 238 Nm. Therefore you must ensure that all the rotor head components can accept 2.3 the torque they are seeing today. This includes the mast and the bendix a ring gear.
The other thing is the motor. From calculations I made a hydraulic prerotator is about 50% efficient. That means that if your pump absorbs 34 kW your motor can only deliver about 17 kW. That might tie in with your motor running slower because of the ring gear. I imagine that properly engineered this system should get you to just over 300 rpm but I'd be very careful about the extra torque on the rotor head.
I think you'd be better looking at the existing mechanical system and find out what is limiting your pre rotator speed today and work on improving that. From memory the ELA has a straight forward mechanical system so I suppose the first thing to limit your RRPM would be the slipping belt clutch. Is it properly set up or can you find a better V belt drive system. Go on line and check the Gates website they give you all the formulas to calculate the best belt system.
Keep us informed about how you get on with this and send us some photos.
I'd be interested if you could post the references of your pump and motor.
Somewhere I posted a graph of my rotor speed against engine speed during pre rotation, this gives you a very simple indication if your clutch is slipping or not. I just filmed the two RPM gauges during a rotor run up and plotted the graph from the film.
Mike G
These seem very powerful but just to continue brainstorming, remember that your first problem will be the available gear ratio of bendix and ring gear. This is usually between 8 and 12 so if we say you want to pre rotate to 350 rpm your motor must deliver it's max power at about 3500 rpm. If your motor delivers 41 kW at 6000 rpm it will probably deliver half or less than half at 3500 rpm.
If it delivers say 20 kW, at a rotor rpm of 350 rpm that's about 545 Nm of torque at the rotor. If you pre rotate today to about 200 rpm that takes about 5 kW which is about 238 Nm. Therefore you must ensure that all the rotor head components can accept 2.3 the torque they are seeing today. This includes the mast and the bendix a ring gear.
The other thing is the motor. From calculations I made a hydraulic prerotator is about 50% efficient. That means that if your pump absorbs 34 kW your motor can only deliver about 17 kW. That might tie in with your motor running slower because of the ring gear. I imagine that properly engineered this system should get you to just over 300 rpm but I'd be very careful about the extra torque on the rotor head.
I think you'd be better looking at the existing mechanical system and find out what is limiting your pre rotator speed today and work on improving that. From memory the ELA has a straight forward mechanical system so I suppose the first thing to limit your RRPM would be the slipping belt clutch. Is it properly set up or can you find a better V belt drive system. Go on line and check the Gates website they give you all the formulas to calculate the best belt system.
Keep us informed about how you get on with this and send us some photos.
I'd be interested if you could post the references of your pump and motor.
Somewhere I posted a graph of my rotor speed against engine speed during pre rotation, this gives you a very simple indication if your clutch is slipping or not. I just filmed the two RPM gauges during a rotor run up and plotted the graph from the film.
Mike G
sadegh_865
Newbie
Mike
yes u are right, these are powerful but i selected them because we had in stock only these types!
my selection is piston motor and piston pump type, u can find on REXROTH website. as i know this type has high efficiency about 85%-95% but much expensive!
i think if we use a clutch system like the one in the photo with some differences, we can come over slippage problem to some extent:
Mike,thanks for warning about rated toque on ring and rotor head, i'll be carefull in test.i'll give detailed information and photos after work finished and we get to a final design.
Mike, could i have ur hydraulic system calculation that u did before?
Sadegh
yes u are right, these are powerful but i selected them because we had in stock only these types!
my selection is piston motor and piston pump type, u can find on REXROTH website. as i know this type has high efficiency about 85%-95% but much expensive!
i think if we use a clutch system like the one in the photo with some differences, we can come over slippage problem to some extent:
Mike,thanks for warning about rated toque on ring and rotor head, i'll be carefull in test.i'll give detailed information and photos after work finished and we get to a final design.
Mike, could i have ur hydraulic system calculation that u did before?
Sadegh
Last edited:
Mike G
Junior Member
- Joined
- Jun 16, 2005
- Messages
- 1,918
- Location
- Lillebonne France
- Aircraft
- Owned Magni M16 now ELA 07
- Total Flight Time
- 550FW + 500 gyro
Sadegh
It looks like the system in your photo runs all the time because it's a toothed belt, unless there's a clutch hidden in there some where that I can't see.
I'm not on my computer at the moment and will attach my spreadsheet calculation as soon as I start to work on my computer.
Is your pump and motor in aluminium or steel and what pressuer do you intend to run at?
Mike G
It looks like the system in your photo runs all the time because it's a toothed belt, unless there's a clutch hidden in there some where that I can't see.
I'm not on my computer at the moment and will attach my spreadsheet calculation as soon as I start to work on my computer.
Is your pump and motor in aluminium or steel and what pressuer do you intend to run at?
Mike G
sadegh_865
Newbie
Mike
If u watch accurately,there is an electric clutch inside the pump pulley...
Sadegh
If u watch accurately,there is an electric clutch inside the pump pulley...
Sadegh
