ScuderiaEV
1 µW
- Joined
- Jun 16, 2009
- Messages
- 2
Motorcycle aerodynamics article;
http://www.tonyfoale.com/Articles/Aerodynamics/AERO.htm
http://www.tonyfoale.com/Articles/Aerodynamics/AERO.htm
Motorcycle class Hub Motor
- Thread starter markcycle
- Start date
todayican2
100 W
- Joined
- Apr 22, 2009
- Messages
- 139
Thanks Jeremy, I have a question for you, if you feel its off topic (probably is) pm me, but here is the question:
I guess I am an "armchair aerodynamacist" and have read that the front matters less then the back, I wonder how much? I am building a low slung trike, once its close enough ill decide on the motor, possibly Marks, ill see if "weight bloating" strikes my 500 lb target..
on the nose of the trike, I could save a lot of money and time if I just smootly bring the nose straight down over the front wheels instead of build the "front of the teardrop" fairing. just how important do you think the smooth curve is up front?
I guess I am an "armchair aerodynamacist" and have read that the front matters less then the back, I wonder how much? I am building a low slung trike, once its close enough ill decide on the motor, possibly Marks, ill see if "weight bloating" strikes my 500 lb target..
on the nose of the trike, I could save a lot of money and time if I just smootly bring the nose straight down over the front wheels instead of build the "front of the teardrop" fairing. just how important do you think the smooth curve is up front?
dave.com
10 mW
markcycle said:
liveforphysics
100 TW
markcycle said:
On a superbike with full fairing and a rider down in a deep tuck, it takes about 75-85hp (56-63kw mechanical) continuously delivered to the rear tire to reach 140mph.
This is a motor featuring a double wide 530x stator. If you look at how that works out, you have a motor with slightly less power potential than a pair of 530x motors (if you want a technical explanation for why that is, I can do it for you).
If we give a generous 85% efficiency, you're looking at needing a continuous 65-75kw. In other words, at 120v, you would need to be continuously dumping ~541 to 625amps.
markcycle
10 kW
liveforphysics said:
First off I don't want to argue but its not a double wide 530X so lets start there. It has 30% more copper, different stator design from material to slot depth to improved flux path via more Si steel in the right places.
It started out as a double wide X5 but it ended up much improved and different than an X5
Eff is higher than a X5 for many reason first the ratio to slot length to end winding is much lower. The copper that is not in iron is just resistive losses. if you keep the copper that is not in iron short compared to the copper that is in iron you can raise the Eff of the motor. If you look at an X5 the ratio of copper in iron to out of iron is about 30/70 compared to the 600 series which is about 10/90. This brings the 600 series Eff closer to a axial flux motor, which have no end losses.
So what can the 600 series do, as I said in the past 144 volt and 300 amps is possible for Short durations. How that translates to speed is yet to be seen. Because of the torque differences between gas and electric motors its not a straight 1 to 1 comparison and only testing will tell.
Mark
Jeremy Harris
100 MW
It's difficult to say how much more the rear shape has an effect than the front, particularly when down near the road surface, where there will be a lot of interference drag from the interaction with air trying to get under the trike. My best guess is that changing the shape of the front from no fairing to the very best rounded shape might make an overall impact of maybe 15% to 20% the drag coefficient. The rear end and underbody shape would have the lions share of the effect on a trike.
Interesting figures for the power needed to do 140mph. I wonder how fast Cedric Lynch's bike was when flat out? We know he averaged 87mph and hit 97mph at the Sulby trap, but my gut feeling tells me that he must have been well over the ton in places to get that average speed. If we assume that he had around 50hp available at the wheel (seems reasonable) then it looks as if you might need a bit more power than this to hit 140mph. I doubt there is a significant drag difference between the GXR and a superbike, maybe 5% or so at most. Frontal area would be pretty much the same, too, as it's dominated by the size of the rider.
How much power do you think this hub motor will produce, Mark? It looks like you're a fair way off it's limit in the testing you've done so far.
Jeremy
Edited to add:
Whoops, Our posts crossed, it looks like the motor is good for around 58hp max, into the sort of speed range being discussed.
Interesting figures for the power needed to do 140mph. I wonder how fast Cedric Lynch's bike was when flat out? We know he averaged 87mph and hit 97mph at the Sulby trap, but my gut feeling tells me that he must have been well over the ton in places to get that average speed. If we assume that he had around 50hp available at the wheel (seems reasonable) then it looks as if you might need a bit more power than this to hit 140mph. I doubt there is a significant drag difference between the GXR and a superbike, maybe 5% or so at most. Frontal area would be pretty much the same, too, as it's dominated by the size of the rider.
How much power do you think this hub motor will produce, Mark? It looks like you're a fair way off it's limit in the testing you've done so far.
Jeremy
Edited to add:
Whoops, Our posts crossed, it looks like the motor is good for around 58hp max, into the sort of speed range being discussed.
michaelplogue
10 kW
Mark -
Two questions:
First: With this motor being - for the most part - based on the Crystalite design, can we assume that we would not be able to do the Delta-Wye modification with it?
Second - would there be any difficulties with fitting this motor into a 15" motorcycle rim (36 hole)?
Thanks!
Two questions:
First: With this motor being - for the most part - based on the Crystalite design, can we assume that we would not be able to do the Delta-Wye modification with it?
Second - would there be any difficulties with fitting this motor into a 15" motorcycle rim (36 hole)?
Thanks!
todayican2
100 W
- Joined
- Apr 22, 2009
- Messages
- 139
Mark, I know I have asked this before, but it seems the motor is exceeding your expectations and I guess it should be asked again.
with say 120v nominal, and a say 700 or 800lb trike, a) do you now think the motor will have the "snot"?
and b) do you think the hub, laced with spokes will have the lateral strength?
pardon the potentially newbie question, but after talking with Matt (Frodus) on another matter, I like his integrity and would like to possibly use the syncromotive controller, good match?
with say 120v nominal, and a say 700 or 800lb trike, a) do you now think the motor will have the "snot"?
and b) do you think the hub, laced with spokes will have the lateral strength?
pardon the potentially newbie question, but after talking with Matt (Frodus) on another matter, I like his integrity and would like to possibly use the syncromotive controller, good match?
markcycle
10 kW
michaelplogue said:
markcycle
10 kW
todayican2 said:Mark, I know I have asked this before, but it seems the motor is exceeding your expectations and I guess it should be asked again.
with say 120v nominal, and a say 700 or 800lb trike, a) do you now think the motor will have the "snot"?
and b) do you think the hub, laced with spokes will have the lateral strength?
pardon the potentially newbie question, but after talking with Matt (Frodus) on another matter, I like his integrity and would like to possibly use the syncromotive controller, good match?
When you say "snot"? well a 603 has snot and up to about 60 65MPH with 120V
Your second question is harder to answer
The bearing system I would say yes though I'm not using tapered roller bearing which is the industry standard for a wheel system your describing.
The rim and spokes I have to say NO can not handle the side loading for sure
Does syncromotive have a brushless controller ready for sale? If so that's great news
Mark
michaelplogue
10 kW
Tires would be 130/90-15.
I'm thinking of doing an additional Hardknock project - this time with your motor (which would be prefect on this bike - no frame mods!).
How are things looking for the high-torque version? Any release dates yet?
.
I'm thinking of doing an additional Hardknock project - this time with your motor (which would be prefect on this bike - no frame mods!).
How are things looking for the high-torque version? Any release dates yet?
.
Mark,
45 kW peak for the 600 series...Would you hazard a guess as to the stall torque of such a moto. As you know I have some good data on real world scooter acceleration so would be curious to know if you are geting close to these numbers (500cc numbers that is).
For non spked bikes have you thought about an extended hub that could bolt directly to a rim (like two piece alloy wheels)
WDYR?
Mike
45 kW peak for the 600 series...Would you hazard a guess as to the stall torque of such a moto. As you know I have some good data on real world scooter acceleration so would be curious to know if you are geting close to these numbers (500cc numbers that is).
For non spked bikes have you thought about an extended hub that could bolt directly to a rim (like two piece alloy wheels)
WDYR?
Mike
markcycle
10 kW
Mikey said:
I'm rating the motor at 30KW peak 10KW continuous.
I'll have real torque numbers after the TTXGP in Ohio. I'm installing a 400 amp peak 200 amp continuous controller for the event and after, I'll take the bike to a Dyno for testing.
The motors both the 603 and 602 are to slow for a scooter wheel. The smallest rim would be a 15 inch rim, even then don't expect to much over 50 MPH. I really recommend a 17 or 18 inch rim to get in the 50 to 80 MPH range with 72 to 144 volt pack. Scooter rims in the 10 inch to 13 inch are going to be to slow for most everybody.
It will be interesting to see what power levels the motor gets pushed to in the real world.
I wanted to add for scooters with wheels in the 10 to 13 inch range Kelly sells hub motors for that market with power levels in the 7 to 10KW range.
EnerTrac is targeting the light to midweight motorcycle market and as such our motors are designed for wheels in the 15 to 21 inch sizes.
Mark
michaelplogue
10 kW
markcycle said:
That would be perfect for what I'd be looking for. It would be used for city riding with some very steep hills. The smaller wheel would be even more to my advantage for the better torque.
markcycle
10 kW
michaelplogue said:
I expect wheels to be in my hands in about 30 to 40 days, all is going very well at the supplier. I'm getting motors in 2 shipments from the first production run, a first shipment will be by air and a larger second shipment by ocean.
Mark
vax
100 W
Just a thought...why using torque arm? Instead, I'd bolt the hollow shaft right to the swingarm.
michaelplogue said:
Generally true if you're hitting a current limit with both wheel sizes, otherwise that generality might not be universally applicable. I mean, yes, you'd have more torque at a low speed (So the acceleration would be better), but you may have less torque on a smaller wheel at a high speed since the no-load rpm corresponds to a less speed, so you might actually go up a hill slower on a hill. This can all be checked by doing your simul... err, I mean physics. :wink:
markcycle
10 kW
michaelplogue said:
The key to it working is to keep your target speed (the top speed you want to achieve) about 15 MPH below the no load speed. The no load speed will determine the right voltage. Then be sure you have enough amps to handle the added load for the steepest hill you expect.
With a hub motor the tire circumference and voltage are both adjustment variables for no load speed. This is why I am always interested in the tire being used and not just the rim size.
Sure there are many other factors, but follow these guide lines and the design should be a success. This is all based on a 300 to 400 pound motorcycle.
Mark
Jay64
100 kW
markcycle said:
I was actually just talking to my old tire sponsor about this two days ago. I was asking if they had any good race type rubber in the 18" size and he suggested a 17" tire with a taller profile to get near the same circumference. As far as good race rubber is concerned, 17" is very popular. I did find an Avon 18" tire that is used on a lot of vintage racers though. Looks promising. Mark, have you looked into any wider rim options? I think for the sportbike test bike we have been talking about, I would like to try and get as wide a tire as possible for the corner speeds I am going to try to pull off.
markcycle
10 kW
Jay64 said:
How wide a rim are you thinking? What is generally used? 3 inch rim and a 140 tire seems reasonable. I don't see a limiting factors in the rim width within what is used for performance sportsbikes. Its just that we will have to get the wheel built ourselfes.
Mark
liveforphysics
100 TW
My bike came with a 190 width rear tire. I would always grind off the edge where it transitions from tread to sidewall, and the bike would slip around. No fun. I changed it to a 175 width to provide less contact when the bike is upright, and better traction and contact when the bike is laying on its side. Now I don't ride off the edge of the tire as often, which means less slipping around in corners. Feels less stable at high speeds on straights, but turn-in is loads better than the stock tire. Since upright traction isn't going to be a concern, a narrow-ish tire might not be too bad of an idea for increasing cornering area contact.
Jay64
100 kW
If you have a rim that is wide enough for a 190 tire and you put a 175 tire on it, you are actually stretching the 175 flatter.
liveforphysics
100 TW
Different profile on the 175 as well. Also, the 190's that come with a GSXR1000 definately look like the tire is tucked in on the sides, and that the rim was made to fit a more narrow tire.
I think the way it goes for cornering area, is anytime you increase profile and decrease series, you increase your cornering patch and decrease your upright patch. That was the change I made for my bike, and it really improved the cornering. But, I don't know how much of that effect came from the new tire dimensions, and how much came from getting that scrubbed down to cords 190 tire changed for new rubber.
I think the way it goes for cornering area, is anytime you increase profile and decrease series, you increase your cornering patch and decrease your upright patch. That was the change I made for my bike, and it really improved the cornering. But, I don't know how much of that effect came from the new tire dimensions, and how much came from getting that scrubbed down to cords 190 tire changed for new rubber.
Jay64
100 kW
Mark, I found a 120/80-18 in some pretty good rubber. I think that is what I will end up going with for the track test here at Jennings GP. The 80 will help to make up for the fact that I don't have ride height adjustments on the bike I plan to use as a test bed for the motor.
81dieselrodeo
1 µW
- Joined
- Jul 24, 2009
- Messages
- 2
Frickin' brilliant! I had quite a bit of 'dreamstorming' of something just like this, but I'm broke and it has remained a dream.
I have an '07 ex250 with 35,000 miles on it (and rising). I no longer commute the long distance that I bought it for.
I'm not so much interested in 70+ mph, as I am in range... 15 years of studying EV tech tells me I'm not going to be happy about that, but LiFePO4 still beats Pb...
Unfortunately, I've taken really good care of this engine... It still runs like new even after doing 10k+ RPM for 3+ hours every day for 2 years... Blow up and give me an excuse already!
I have an '07 ex250 with 35,000 miles on it (and rising). I no longer commute the long distance that I bought it for.
I'm not so much interested in 70+ mph, as I am in range... 15 years of studying EV tech tells me I'm not going to be happy about that, but LiFePO4 still beats Pb...
Unfortunately, I've taken really good care of this engine... It still runs like new even after doing 10k+ RPM for 3+ hours every day for 2 years... Blow up and give me an excuse already!
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