Best time on 1/4 mile with an X5 hub motor (your opinions ?)

[Doctorbass]

The question to you is:


According to you, What would be the best possible time on the quater mile drag race for an electric bicycle using a single X5 motor?

(According your idea of the max burst power an X5 can take for 15-20 sec if it is at ambient temp when it start)

.. and assuming that the phase wire size, battery current and controller current are not the limit)

(Well.. imagine that the weakest part in the system is the motor)

( I can give you an idea of the power i've put into my x5...15.1kW during 3-4 sec)


Doc

 

[John in CR]

How many motors can we use? What about rider weight, since that's everything?

 

[Doctorbass]

How many motors can we use? What about rider weight, since that's everything?

Total weight = 250pounds

Motor number: 1

Motor type: X5... 5302 or 5303

I calculated that with 19kW and a 5303, i could get like 13-14sec on the 1/4 mile... according to the SWbluto simulator.

I think that for short period like that, the weakest part on the X5 hub motors is the phase wires... I think that eventhough these hub motor are rated 750W, and that we alerady push many times 5 and 10kW.. and me, 15kW from now... it<s possible to still push the limit to 20kW for short period of time.

When i did my speed record of 94.3kmh last summer, the motor temp increase was only 20 celsius!!! for 15kW burst during 19.3sec.

now i wonder what could be the MAX limit of these motor for BIG POWER BURST of 15sec...

-Magnets depolarisation?

-Winding insulation burn?

-motor axel twist?


I plan around 200-250A and 135V this summer...

-Kelly controller
-Current limit: MAX
-Voltage limit : MAX
-Burst time: 15sec

BTW.. I think i'll change the 45A powerpole connnector on the motor phase :lol:

Doc

 

[John in CR]

Sounds pretty optimistic. Luke runs 3 times the power to weight ratio in his car to run 11sec.

 

[RPA]

I predict around 17's with the largest factor being top speed. What's the expected max speed?

 

[Doctorbass]

Well, Based on the past results, i expect to break the 120kmh barrier.

The past setup had a controller set to 75% max throttle ( i forgot to reprogram it.....to 100% :x )

I had 92.4V nominal, 150A , total weight around 250 pounds, 5302 on a 20inchs wheel and a front wind of 20-25 kmh.... and did 94.37kmh ( GPS)

Now with 120V nominal 220A , 100% throttle and NO WIND ( I hope...) , The 120kmh barrier should be easy to break.

I also might test for the best quater mile using a 5303 instead.

 

[gogo]

I calculated that with 19kW and a 5303, i could get like 13-14sec on the 1/4 mile... according to the SWbluto simulator.

That sounds about right. With a ~50 HP motorcycle @ ~500 lbs. total, I used to do 12sec.@100 MPH. I did need a wheelie bar, however.

 

[RPA]

Well, Based on the past results, i expect to break the 120kmh barrier.

The past setup had a controller set to 75% max throttle ( i forgot to reprogram it.....to 100% :x )

I had 92.4V nominal, 150A , total weight around 250 pounds, 5302 on a 20inchs wheel and a front wind of 20-25 kmh.... and did 94.37kmh ( GPS)

Now with 120V nominal 220A , 100% throttle and NO WIND ( I hope...) , The 120kmh barrier should be easy to break.

I also might test for the best quater mile using a 5303 instead.

I can't wait to hear how you do. I'd be very impressed if you pulled off 14's. I'm mostly interested in the top speed though. I'm all for the max speed and efficiency aspect of ebikes.

 

[liveforphysics]

I can't see it ducking 15.0seconds in the 1/4.

Like all drag racing, it's going to come down to the 60ft time. To duck a 15.0 with these power to weight ratios, you're going to need to be seeing 1.7-1.8sec 60' times, and i just can't see a hubmotor reaching that.

 

[LI-ghtcycle]

Go for it!

I'd love to see how you do, just out of curiosity how fast was your 1/4 mile time when you made the record?

Also, I have to say that I think your real ace in the hole is gotta be aerodynamics. I don't know your budget, and if you have any access to some form of wind tunnel, but I know that with smoke and models some people have been able to have pretty good success even low budget.

The single biggest advantage after power to weight ratio most motorcycles enjoy, is the small aerodynamic cross section. If you can capitalize on this strength I believe your going to gain just about as much as anything else given about the same power you have available now.

Looks like you had a pretty nice fairing on your record making bike, just curious if you were able to test it's aerodynamics in a tunnel or such?

I know your budget is farm more than mine, wish I had half your knowledge, but the only way any of this stuff really gets done is the practical application.

I applaud your making the E-Bike more known and attractive to the general population, with out people like you, many sports don't become popular.

I am also curious how much sponsorship you have received for your accomplishments? I would think many E-Bike companies would benefit greatly from your success! 8)

 

[dequinox]

When i did my speed record of 94.3kmh last summer, the motor temp increase was only 20 celsius!!! for 15kW burst during 19.3sec.

-motor axel twist?

Doc

Doc what kind of torque-plates do you use on the killabicycle? Hardened T1 maybe? It's a wonder to me that the corners of your axle didn't get rounded-off on a 15kw run like that!

-Dylan

 

[gogo]

The single biggest advantage after power to weight ratio most motorcycles enjoy, is the small aerodynamic cross section.

Compared to what?

http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=955
Sportbikes have Cx values between .3 and .6, touring bikes have values between .4 and .9, and cars tend to have values of between .26 and .36.

 

[Doctorbass]

I can't see it ducking 15.0seconds in the 1/4.

Like all drag racing, it's going to come down to the 60ft time. To duck a 15.0 with these power to weight ratios, you're going to need to be seeing 1.7-1.8sec 60' times, and i just can't see a hubmotor reaching that.

Yes, iot might be 16, 15 or 14sec.. I can't really be sure.. but according to the SWbluto java simulator, it's somewere to 14-15sec. it depend also ALOT of the wind during the test!

I was impressed on how accurate this simulator and the one of ebikes.ca was accurate WHEN YOU ENTER THE EXACT PARAMETERS IN THE EXACT CONDITIONS THAT REFLECT REALITY like i did.

I am considering maybe adding a front hub motor.. maybe my actual 5302 will go to the front and the 03 will go to the rear.

At the voltage i'll use,, the no load speed of the 03 will still be lower than the speed of the 5302 on load so there is no problem with that... the 03 will push me for torque for the 0-60 fts and the 02 powerband will take the rest at the middle of the max speed, helped by the 03 a bit.

Not sure i'll run two motor... but i might consider that.

My actual battery can take up to 500A ( 4p a123) so 200 A on the 03 controller and 300 Ain the 02 controller wold be great ( two motor and two controller)

Total power around 30kW ( 40hp)... for a 280 pounds ebike.. that could be great!

But i'll still test and try to exploit the 5302 at the max i can do for begining.

The 03 on the simulator is giving me a big difference on the 0-60fts... alot better than the 02.. but.. .it top speed faster but lower speed...

I discussed with someone at work about drag racing ( he is an old drag racer.. and like you said, he also said that the 0-60 ft is alot important fo rthe 1/4 time.

Doc

 

[Doctorbass]

Go for it!

I'd love to see how you do, just out of curiosity how fast was your 1/4 mile time when you made the record?

Also, I have to say that I think your real ace in the hole is gotta be aerodynamics. I don't know your budget, and if you have any access to some form of wind tunnel, but I know that with smoke and models some people have been able to have pretty good success even low budget.

The single biggest advantage after power to weight ratio most motorcycles enjoy, is the small aerodynamic cross section. If you can capitalize on this strength I believe your going to gain just about as much as anything else given about the same power you have available now.

Looks like you had a pretty nice fairing on your record making bike, just curious if you were able to test it's aerodynamics in a tunnel or such?

I know your budget is farm more than mine, wish I had half your knowledge, but the only way any of this stuff really gets done is the practical application.

I applaud your making the E-Bike more known and attractive to the general population, with out people like you, many sports don't become popular.

I am also curious how much sponsorship you have received for your accomplishments? I would think many E-Bike companies would benefit greatly from your success! 8)

LI-ghtcycle, I cold have acces to a wind tunnel near Quebec city.. at 200km at Sherbrooke univercity. When i worked in their physics department I had to build and install a green 2Watts laser line scan for the high speed camera measurement fo rthe vortex etc... and i might still have a kind of VIP acces for test so.. that would be cool

The actual setup was done by eyes estimated... and i have to say it work very well.. i hear only very little turbulence at 90kmh and up.... the ebike dont slow down too fast...

fo rthe fairings, I choosed to use something for an old univercity solar car project.... a lexan dome on the front to open the "wind loop "and a kind of eliptic edge on rear to close the "wind loop" ( i have no word i english to explain that...)

I measured around 0.55 sqr m sectional on the front and a very low rolling resisatnce dur to the 110 psi 20" tires.

Yes i had some sponsor, but that 's mainly for a rebate on some components. The total estimated ebike cost was around 1500$

I have not asked for any money for that popularity "gain" for the ebike market.. i just want to make ebike more popular and to be better known with all their advantages and.. power! as well!

Thanks for your appreciations!

Doc

 

[Doctorbass]

When i did my speed record of 94.3kmh last summer, the motor temp increase was only 20 celsius!!! for 15kW burst during 19.3sec.

-motor axel twist?

Doc

Doc what kind of torque-plates do you use on the killabicycle? Hardened T1 maybe? It's a wonder to me that the corners of your axle didn't get rounded-off on a 15kw run like that!

-Dylan

Since the original rear swing arm of that kid bicyckle was already made very strong.. i just added one 9C motor torque arm i had left.

That 5302 offer more power over a high speed... so the torque is not the same.. it's a higher kV motor. But i agree that with a 5304 or 05, that would not be the same!!!

 

[LI-ghtcycle]

The single biggest advantage after power to weight ratio most motorcycles enjoy, is the small aerodynamic cross section.

Compared to what?

http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=955
Sportbikes have Cx values between .3 and .6, touring bikes have values between .4 and .9, and cars tend to have values of between .26 and .36.

Good question, let me clarify: some had mentioned power to weight ratio, and fast cars that had more power to weight ratio than Doc's E-Bike, so I liken his E-Bike on the drag strip to a motorcycle since it has more weight than a typical bicycle, and the fairing that I saw used in Doc's record making run would give it more of a motorcycle like cross section.

I didn't say it but I was thinking how he could achieve greater advantage with his E-Bike set up compared to a car with greater power to weight ratio. I was just thinking what might not have been talked about as much, but now seeing what Doc used for his fairing, sounds like he has it pretty well in hand, however, I still think for his more specific purpose, if he can get access to the University's wind tunnel, that might produce significant gains in performance.

And don't anyone get me wrong, I am just a shade-tree mechanic and a idea man, I'm not in any way putting myself out there as any kind of "expert". :wink:

 

[Almasi]

I calculated that with 19kW and a 5303, i could get like 13-14sec on the 1/4 mile... according to the SWbluto simulator.

That sounds about right. With a ~50 HP motorcycle @ ~500 lbs. total, I used to do 12sec.@100 MPH. I did need a wheelie bar, however.

I would say around 18 second ...for one reason, there is a big difference between 19KW (25.4HP electric) and an actual power output of 25.4HP, when you put in 25.4 Electric HP it probably produce 15 Mechanical HP so the calculation should be done with the mechanical HP not Theoretical electric HP....

And to add to this, The 1/4 mile calculator seem a bit off when you use it for light vehicle, that's what I found with my Electric Racing Kart, I was hoping for 14 second...and did a 17Flat (due to a low top speed of 120KPH, and lack of power) I will make some change to fix that this summer anyway

Good luck DoctorBass, but I think you're close to the limit of one X5 hubmotor....time to make a bike with two X5

Robin

 

[liveforphysics]

that's what I found with my Electric Racing Kart, I was hoping for 14 second...and did a 17Flat

This is called "track heartbreak." Don't feel bad, it happens to everyone, and happened to me at my first time racing my first car at the dragstrip. Quarter mile calculations had been worked out a hundred times, everything on paper told me 14.5-14.7, at the track I couldn't duck a 16.0 in 5 passes, and broke on the 6th pass. lol

Everybody running in the 17s-18s was dreaming of seeing the 14 displayed.
Everybody running 15s was dreaming of seeing the 12 displayed.
Everybody running 12s was dreaming of 10s.

And anyone who actually runs a 10 in a streetcar only gets there after so much money and work and years of tuning involved that they feel like they should be running 8s by now, but maybe 1 in 10,000,000 (likely need to add a zero) streetcars actually will ever see an 8, and money alone can get you 9s in a streetcar, but not 8s. Takes a driver, skills or real money, and experience to see 8s in a streetcar. It's my dream to achieve it in a FWD 4 cylinder street driven civic without the use of a turbo.

 

[liveforphysics]

Doc-

It always comes down to the 60' time. You shave off 0.1seconds at the 60' mark, and you very often drop 0.3 seconds off the quarter mile time.

For the period of time you're able to dump 15kw into your motor, it's in the 10-20% electrical to mechanical efficiency range.

This means the 15kw of power in that your dumping is giving you about 1.5hp-3.5hp at the most during the most critical part of the race, the 60' area.


Something critical to remember about the simulators. They do not have any compensation for the saturation "knee" of the motors response in reguards to amps vs torque. You're going to be well into that area, and efficiency takes a major step downward after that saturation point is reached.

 

[liveforphysics]

In all my years of drag racing, I've seen a trend that holds constant with all cars around the ~9second to ~15 second range.

This is very odd, and I think it's a property that electrics may have an advantage with. With a normal racecar, when you launch perfectly, and get a very low 60' time, your ET is always lowest. This part makes perfect sense. The part that is very strange is that the trap speed is often much slower on your runs with the best times, and the lowest 60' times.

For example, with my civic, I can run through the traps at 121mph if I badly botch the launch, or run on street-tires, and Im lucky if my ET will duck 12.0.
Yet my fastest ever ET had a trap speed of 113mph... 8mph slower going through the traps (and just coasting the last 200ft), and yet 1.1 seconds faster than when i run a 12.0 at 121mph...

Unconditionally, even on a run where I don't even use 5th gear and just coast the last 200ft of the track (as I often do), my ET will ALWAYS be lower if my 60' was lower. No matter what you do, if the 60' time improves, the quarter mile time improves. We've even seen this hundreds of times for cars that have even miss-shifted in the higher gears, or just coasted the back section, if the 60' time improves, the 1/4mile time improves like some kind of voodoo magic relationship.

For the same vehicle in the same state of tune/power/tire/weight etc. When you have a run where the trap speed goes UP, the ET is almost always slower, and visa-versa.

There are 10's of thousands of discussions on all car forums as to why this effect happens. I'm very interested in seeing if the effect happens with the unique torque curve of an electric motor, and inability of the motor to "bog". Normally we rev up to some crazy high launch RPM, then slip the clutch to control the application of stored momentium in the crank/flywheel of the engine and to keep the engine operating in it's peak torque range, because if RPM's drop out of the efficient operating range, the motor bogs and that race is lost. For my civic, if the tach ever drops below 6,000rpm while I'm launching, I might as well get out and walk. lol An electric motor has more of an opposite effect than this, so it will be very interesting to see how they do as they become more active in racing.

 

[gogo]

In all my years of drag racing, I've seen a trend that holds constant with all cars around the ~9second to ~15 second range.

This is very odd, and I think it's a property that electrics may have an advantage with. With a normal racecar, when you launch perfectly, and get a very low 60' time, your ET is always lowest. This part makes perfect sense. The part that is very strange is that the trap speed is often much slower on your runs with the best times, and the lowest 60' times.

Ya, I was initially puzzled by this when I was racing my motorcycle at the drag strip. Here's the best way I've heard it explained:

Imagine a drag race between two identical vehicles that have a terminal velocity of 100 MPH, but one gets a flying start @ 100 MPH. Because the flying start vehicle spends a higher percentage of time near the terminal velocity, it has a lower ET.

With a one-speed hub motor it may be advantageous to spin it up into a high-power portion of the power curve and let the tire contact patch be the "clutch" between the motor and the road. That'll get you to where a wheelie bar would earn its keep.

Doc's idea to use front and rear hub motors with different power peaks would be fun to experiment with.

 

[Doctorbass]

Yeah guys.. I see what you mean...

I never raced in drag racing with ICE car... just ebike form now...

I dont really know the best trick.. I have people at work that are still drag racer like one with his vette Z06 and some 10 sec cars.. that i discussed with.

I like the Killacycle, White zombie, tesla, ttxgp car and motorcycle, etc but i still dont have the money to build things like that.. I just bought a new house this year so..... :lol:

The electric drag racing bicycle is an interesting way for me since nobody tried that from bow.. or.. at least.. from what i know..

I only had two experience on the drag lane using ebikes and that was completly amazing!!

i'm addicted and i love the acceleration we can get pussing the limit of these X5, Methods, steveo, me and others...

I want to find the real limit of a single X5 for a 15-20sec burst.

Controlles and battery are not the limit i'm sure!...

Luke, To get more realistic data I expect to datalog every possible data during the test i'll do this summer. GPS speed, distance and elevatio data, motor power vs time, real power output calculated with my Beltronic FX2 accelerometer and hp calculator, exact weight of the ebike, wind, tire pressure etc.

I hope we will all learn something with that and be able to compare with ICE car or motorcycle.

Double motor setup would be very impressive and the 4p a123 battery can certainly sustain dual controller and motors.

Adding like 30pounds to the ebike with 15kW could certaily modify the power to weight ratio!!

Steveo will also push the limit if he decide to go with a 5303 and 145V..

w'll see!

Still alot of work to do! + some more ebikes for the familly, newby near Quebec that also want their X5 conversion and that will want help... as well.... :lol:

My move to a new house ...potentially a trip to Europe i hope with my wife.. etc... OMG.. so mouch work!

Doc

 

[liveforphysics]

I like the Killacycle, White zombie, tesla, ttxgp car and motorcycle, etc but i still dont have the money to build things like that..

I doesn't need to be expensive. You've got the batteries and controller all ready, that's the most expensive part.
Take off the frock, and buy one of the motors Markbeletti found in this thread, and the 15kw you pump out will be 12kw of go, and 3kw of heat, rather than 3kw of go and 12kw of heat.

http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=16728&p=249625#p249625

I only had two experience on the drag lane using ebikes and that was completly amazing!!

Once you get the racing bug... well... life changes... I'm glad to hear you loved it though, because I want you helping the electric revolution even more by building badass E-racing stuff!

Luke, To get more realistic data I expect to datalog every possible data during the test i'll do this summer. GPS speed, distance and elevatio data, motor power vs time, real power output calculated with my Beltronic FX2 accelerometer and hp calculator, exact weight of the ebike, wind, tire pressure etc.

Just mark off 60' with a tape measure on a quiet road or parking lot some where, and get a friend/wife with a stopwatch to time it. Any changes you can make that shorten up this time will reflect VERY postively on your quarter mile time, and it doesn't cost you $50 track fee's and hours of waiting between each run, which makes it awful expensive and time consuming to get valuable data gathered.

I hope we will all learn something with that and be able to compare with ICE car or motorcycle.

Hell, yeah, that's the spirit! I wana see you get there! If you pick-up that motor I linked above, you'll have a big piece of the puzzle needed to reach your goal.

Best Wishes,
-Luke