What motor would you choose for a 25kw paramotor setup

Ratking

Ratking

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Hello

I have a dream of building an electric paramotor for my paraglider. A friend of mine is a very experienced pilot and told me that I would need 25kw for my weight and giving a proper safety factor in case of turbulence and air pockets that can cause sudden loss of speed and altitude. The motor would only need 25kw for peaks and far less continuously.
The weight is another issue, total weight of the paramotor should not exceed 30-35kg, where as 20kg of them is already spoken for(battery pack). A tandem paramotor with 30kw gas motor weighs in around 35-40kg and is very hard to run/start with.
So I need to keep the weight down, but be able to get a good amount of power out for short amount of time.
Price is another issue, this is an experiment, I don't have several thousand dollars for this, if I had, I would buy a Joby or the like.
Do you good folks have any suggestions with the above in mind(An explanation about why you think your motor is suitable is appreciated)? Bonus question is to pair it with a suitable controller that is "cheap" and light.

Key features:
25kw for peaks
Less than 8-10kg
Easy to match to a controller
Not too deep/thick
As cheap as possible(this is a relative term)
 
nieles said:
at what rpm do you need 25kw peak?
Click to expand...

From what I have read of information, the gas powered paramotors run the propeller at 2000-2500rpm max. I will try to use a large diameter low pitch propeller to keep the rpm to around 2000 or less(depend on efficiency/rpm/thrust) . I will use a belted reduction, so the motor rpm range I can adjust to is between 750-7000 rpm(increase or decrease the ration, dependent of the motor Kv)
Is that a good enough answer?
 
i was thinking maybe you can mod a hub motor, with lots of air cooling. and run it at higher rpm to get more power

but not sure if you can find an hub motor powerful enough.
maybe johninCR's hubmonster?
 
Check out hubmotors designed for cars. They have a stub axle, meaning, no support needed for both ends of the axle. A scooter hub needs support for both ends of the axle.
 
25kw is a ton of power for a paramotor (source: I've built hundreds of them, working with a well known Compact Radial/ultralight engines company)

how much do you weigh???

This is a great project idea and I'd love to see how it turns out. never seen an electric paramotor... I want to build an all-electric ultralight plane eventually. Amphib landing... maybe folding wings, like the very elegant Icon A5. except lighter... the A5 has a lot of extra weight for aesthetic details (again, built em)
 
Dude, 25kw is like 33hp... there are small aircraft flying with 60hp.
I dont think you need that much.. dont most of them run off of a 350cc or less 2-stroke?

or is this a tandom-cart setup? I can see that taking 30hp.
 
I like Harold's idea. Maybe you can get a custom 2T 273mm V3 car hub motor from QS. Just drop them a mail...they night even drill the holes for you. Low speed means high efficiency for a prop. Maybe 1800rpm or so is sufficient? I think their 32pole motors can spin this fast. With a 2t wind you should be OK with 72V. Then pair it with a 700A Kelly 8080
 
Deafcat said:
25kw is a ton of power for a paramotor (source: I've built hundreds of them, working with a well known Compact Radial/ultralight engines company)

how much do you weigh???

This is a great project idea and I'd love to see how it turns out. never seen an electric paramotor... I want to build an all-electric ultralight plane eventually. Amphib landing... maybe folding wings, like the very elegant Icon A5. except lighter... the A5 has a lot of extra weight for aesthetic details (again, built em)
Click to expand...

Nice that we have someone with experience building these. I'm weighing in at 110kg. With equipment and a paraglider/motor it would easily be +150kg. With the rule of 50% thrust of ready to fly weight, I should aim at at least 75kg thrust. If possible I am after a way of calculating backwards with lets say 80kg/800N thrust and see how much power is needed for a given propeller size/pitch and shape. But I have not been able to find that.

The Icon looks great, how much power is needed for take of from water?
 
MrDude_1 said:
Dude, 25kw is like 33hp... there are small aircraft flying with 60hp.
I dont think you need that much.. dont most of them run off of a 350cc or less 2-stroke?

or is this a tandom-cart setup? I can see that taking 30hp.
Click to expand...

Maybe I don't need that much power, but from what I can gather from gas powered paramotors, 21.5hp is only enough for a 230lb man. And that is the absolute limit, the climibing rate would be sour.

http://blackhawkparamotor.com/paramotors/blackhawk-r120-paramotor/

Or this one, 28hp gives 75-80kg thrust. More what I am after.

http://www.parajet.com/us/zenith
 
Harold in CR said:
Check out hubmotors designed for cars. They have a stub axle, meaning, no support needed for both ends of the axle. A scooter hub needs support for both ends of the axle.
Click to expand...

crossbreak said:
I like Harold's idea. Maybe you can get a custom 2T 273mm V3 car hub motor from QS. Just drop them a mail...they night even drill the holes for you. Low speed means high efficiency for a prop. Maybe 1800rpm or so is sufficient? I think their 32pole motors can spin this fast. With a 2t wind you should be OK with 72V. Then pair it with a 700A Kelly 8080
Click to expand...


I found the car hub motor, but it is extremely heavy. I would also need a bearing that is capable of axial loads, as the propeller will apply all the force through the motor. ¨Thank you for the input, it wold be great if it did not weigh in at 22.5kg
 
How about multiple smaller motors each driven by their own controller ? This will give you redundancy, if 1 of your 4 motors fail you will still be OK...
4 RC motors with 4 propellors is the way I would go.
 
I was thinking about this project lastnight. This may be my favorite ES project right now. It should be almost silent and vibration free, like a glider.
The motor isnt really the holdup. There are a few that could work. What I was thinking about was the battery.
I would imagine you want lightweight, so it would be lipo... but for 1 hour of flight, you're looking at a pretty large battery.
Where do you plan to put it?

nutspecial said:
I'm liking this topic and idea, but falling out of the sky is on my list of ways not to die lol.
I guess those things have parachutes if you're high enough?
Click to expand...

They ARE parachutes. They're pretty neat. If I lived in a different part of the country I would be doing it too.
 
MrDude_1 said:
I was thinking about this project lastnight. This may be my favorite ES project right now. It should be almost silent and vibration free, like a glider.
The motor isnt really the holdup. There are a few that could work. What I was thinking about was the battery.
I would imagine you want lightweight, so it would be lipo... but for 1 hour of flight, you're looking at a pretty large battery.
Where do you plan to put it?

nutspecial said:
I'm liking this topic and idea, but falling out of the sky is on my list of ways not to die lol.
I guess those things have parachutes if you're high enough?
Click to expand...

They ARE parachutes. They're pretty neat. If I lived in a different part of the country I would be doing it too.
Click to expand...

I don't have space or capacity to have a spare shute. I have a gentle wing anyway, don't think anything will happen as long as I fly on days without to much turbulence. There are 7 billion people on earth anyway, so I won't be missed :D

I have a few of these modules http://www.enerdel.com/me350-049-moxie-battery-module/
If I choose to go the RC-motor route, they are already configured for 12s2p. It is possible to configure them to what you want from 2s-xxs2p.
Two modules gives me a smidge over 3kwh, that is the least I can have. Fly time is not a big issue, I just want to be able to fly where I want. Short trips are enough for me. If I get desperate, I can just put another module on, it will only be harder to take of.
 
I found an interesting site that shows a concept http://www.electricppg.com/Developments/Elektro/Elektro_electric_paramotor.htm that utilizes two 80-100 outrunners that together produce 50kg of thrust . That is very promising, because three of them will give me my 75kg of thrust. Very easy to make also. I have the motors and batteries already. I only need a few controllers, propellers and weld a frame for me to get flying ;)
 
I remember watching this video a while back, I have no idea how safe it is : https://youtu.be/V-chiQlyAYU

The motor used is this one : http://www.hobbyking.com/hobbyking/store/__23591__Turnigy_RotoMax_100cc_Size_Brushless_Outrunner_Motor_US_Warehouse_.html
 
That is a dam fine little build.
I hadn't realized all the prop noise, so was wondering what real benefit 'E' would really be. Looks like small/compact is where it really shines. Same as bikes really.

Speaking of, did anyone catch the testing of ratking's linked ppg? :lol:
https://www.youtube.com/watch?v=b9QedZlRwvc
 
Cool project. I would recommend 2 motors. Both high quality and light. The second one with more real world testing and data available but still both look promising none the less.

Revolt 160 - 12kw cont/20kw peak - 8kg - $650 shipped
http://www.revolt.org.il/rv-160models/rv-160pro-2/

Astro 3220 - 14kw peak - 4lbs - $695
http://www.astroflight.com/3220
https://endless-sphere.com/forums/viewtopic.php?f=28&t=74176

Matt Shumaker ('recumpence' here on ES) has the most experience with these motors and is in contact with Astro to make custom motors to his specifications. He could help provide you with probably the lightest and highest quality/reliability of any drive system.
 
There's some lightweight guy using a Revolt 120, but their newer large 160 may be able to do that power, though you may need to go to a bit higher rpm. I'm just wrapping up modding a HubMonster for myself, which is highly efficient and definitely capable of the power you want in the right rpm range if you can go to high enough voltage. I trimmed mine down to just under 14kg, but that's for in-wheel use, and since you wouldn't have impact loads spinning a prop you could remove up to another kilo or so of material. The steel bell housing would make adding a thrust bearing simple. Supporting both sides of the axle can be accomplished as part of your prop cage. The only way to save much weight is using significantly higher rpm motors and a belt reduction. The greater motor noise would be less of an issue due to the prop noise, and the ability to fine tune by changing pulleys is attractive. If your weight is due to height, then I'd definitely look into swinging a bigger prop than typical, since larger props are more efficient, especially with the pilot right in front.

That's my 2 cents. Please be sure to share your progress and results, since many are interested. Hopefully they come up with a significant battery breakthrough soon. Then with guys like Liveforphysics working on multi-rotor stuff, we'll have quadcopters etc that we can ride safely. :mrgreen:
 
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