Streamlined Trike Most Efficient Motor?

[multifrag]

I'm still in planning stage, so the maximum price is not yet set. I've been looking into ''Agni Motors'' or ''Astro Flight''. I will be building 90V45Ah battery with Adaptto controller. Would love to cruise at 50Mph speeds. Due to the aerodynamics of the body it should not require a lot of energy to keep it at that speed. Not sure how close to real world performance the Kreuzotter.de calculator is, but it shows about 800 Watts to keep velomobile at 50Mph. Which is very low. I would appreciate any tips and suggestions as this will be a very time consuming build

 

[Eskimo]

Some shops sell DD-motors with many different winds. If you buy the most fastest winding, you will be happy with 90V.
It will be lightning-fast :wink: I agree that you don"t need very big motor. 1000W or 1500W will make you happy, meaning 35mm wide magnets.
Even 28mm-magnet motor will give you a great ride, if you find one with a fast wind. I am riding one.
I think MXUS has DD-motors with many different winds. Use the strongest spokes you can find. Sideloads on high speed cornering are immense. I am using 3mm moped spokes.
You don"t need lot of amps with that kind of voltage. 10A will give you a good thrust. With that 90V you have to make sure that motor you are using can take that. Others here can say that.
When talking about speed, one thing to play with is of course tire and rim size too.

 

[dogman dan]

I'm not knocking the krutz.

But bear in mind, traveling into 15 mph wind means the numbers for 65 mph must be used. Also, it will take more than 800w drawn from the battery to get to 800w delivered to the wheel.

So you need to build so you can have 1500w when you need it, if not a lot more. But no doubt about it, a really good aero shell can be incredibly efficient. Tiny things make a big difference. I won't be a bit surprised if you achieve 50 mph cruise on 1000w, when you have no wind.

Off topic a bit, I added 3" of height to the windscreen of a large scooter this weekend. I didn't like having to crouch to get my head into the bubble. Getting my helmet out of the wind increased the speed of the scoot by 5 mph, and drastically improved it's ability to go from 75 mph to 85 mph. Aero matters at higher speeds!

 

[AF7JA]

I don't know what model of trike you have; but regular operation at 50mph is probably outside of the design parameters for most trikes. I would be most concerned with general handling at those speeds. Yes, I have ridden mine that fast; however, the geometry was clearly being pushed. The steering felt like I was well outside of the safety margin.

I am not saying that it can't be done; it most certainly can. However, it is more of a stunt than a normal mode of operation.

 

[multifrag]

Some shops sell DD-motors with many different winds. If you buy the most fastest winding, you will be happy with 90V.
It will be lightning-fast :wink: I agree that you don"t need very big motor. 1000W or 1500W will make you happy, meaning 35mm wide magnets.
Even 28mm-magnet motor will give you a great ride, if you find one with a fast wind. I am riding one.
I think MXUS has DD-motors with many different winds. Use the strongest spokes you can find. Sideloads on high speed cornering are immense. I am using 3mm moped spokes.
You don"t need lot of amps with that kind of voltage. 10A will give you a good thrust. With that 90V you have to make sure that motor you are using can take that. Others here can say that.
When talking about speed, one thing to play with is of course tire and rim size too.

I've looked into MXUS 3000W V2. It looks a bit overpowered for my application and would need a gear reduction to keep it at peak efficiency. Could find a proper graph, but the sellers say it's 85% peak efficiency. I would love to find something around 90%. 1500-2000W probably would be more applicable for my use. Do you think building 90V battery would the right choice as adaptto can work with it or should I go with the standard 72V?

 

[multifrag]

I'm not knocking the krutz.

But bear in mind, traveling into 15 mph wind means the numbers for 65 mph must be used. Also, it will take more than 800w drawn from the battery to get to 800w delivered to the wheel.

So you need to build so you can have 1500w when you need it, if not a lot more. But no doubt about it, a really good aero shell can be incredibly efficient. Tiny things make a big difference. I won't be a bit surprised if you achieve 50 mph cruise on 1000w, when you have no wind.

Off topic a bit, I added 3" of height to the windscreen of a large scooter this weekend. I didn't like having to crouch to get my head into the bubble. Getting my helmet out of the wind increased the speed of the scoot by 5 mph, and drastically improved it's ability to go from 75 mph to 85 mph. Aero matters at higher speeds!

Power to the wheel is why I want to get a very efficient motor. 800W would be a in perfect world situation. But with something like Agni motor I would lose 7% to heat.

Not sure how down to earth this calculator is, but it shows that for every 15Mph headwind I lose 10Mph speed. So I'm looking into 1500-2000W motor for efficiency of 90 or over?
Going +50Mph is when Aero start to be really important.

 

[multifrag]

I don't know what model of trike you have; but regular operation at 50mph is probably outside of the design parameters for most trikes. I would be most concerned with general handling at those speeds. Yes, I have ridden mine that fast; however, the geometry was clearly being pushed. The steering felt like I was well outside of the safety margin.

I am not saying that it can't be done; it most certainly can. However, it is more of a stunt than a normal mode of operation.

I'm not gonna be using a prebuilt trike. I will be welding my own. One thing I'm not sure is tires. I'd like to have 2x 20inch tires in the front to keep the wheels stronger and so that the nose would he low and 700c or 29er at the back. The reasoning for the large tire at the back would be ability to pedal. I'd still like to pedal at high speed and a large tire would help me use common gears with out going custom.

 

[gogo]

Try the simulator at http://www.ebikes.ca/tools/simulator.html with a 9C+ 2707 motor.

 

[multifrag]

Try the simulator at http://www.ebikes.ca/tools/simulator.html with a 9C+ 2707 motor.

Is the range graph true to real world?

I understand that NSM13 is not only not efficient but would just die pulling my vehicle, but in the graph it looks like it would work. How is this possible? Should I stick with 90V battery or go to more usual 72V? As you can see in the graph I'd like to have some leeway on the throttle.

 

[gogo]

Is the range graph true to real world?

Only if you are adding 344 Watts of pedal power.

The load is much higher than the motor power in your examples.

 

[multifrag]

Is the range graph true to real world?

Only if you are adding 344 Watts of pedal power.

The load is much higher than the motor power in your examples.

So basically if the ration should be 1:1 or -100W which is what a normal cyclist can do for a long period of time

 

[gogo]

To diddle the simulator, pick a throttle setting that results in a speed value that is a few MPH less than your target speed. Then move the dotted line to your target speed and look in the text chart to see if the load is 100W more than the motor power.

It doesn't work too well to use the watts graph lines to get the 100W difference dialed in.

Here's what I got:

In Iowa you can ride on the interstate as long as you can attain and maintain 40 MPH. 8)

 

[amberwolf]

I'd still like to pedal at high speed and a large tire would help me use common gears with out going custom.

can also add jackshaft with more gears before back wheel. igh is simple, not uncommon on bents for more gears

 

[multifrag]

To diddle the simulator, pick a throttle setting that results in a speed value that is a few MPH less than your target speed. Then move the dotted line to your target speed and look in the text chart to see if the load is 100W more than the motor power.

It doesn't work too well to use the watts graph lines to get the 100W difference dialed in.

Here's what I got:

In Iowa you can ride on the interstate as long as you can attain and maintain 40 MPH. 8)

Brilliant. Thank you. Looks like Nine Continent 2707 will work just fine. This vehicle will be more for countryside

 

[multifrag]

Try the simulator at http://www.ebikes.ca/tools/simulator.html with a 9C+ 2707 motor.

It looks like 9C 2707 is a no go. I looked at it on ebikes.ca and it has no mount for rear cassette...

 

[gogo]

The MXUS motors seemed very close and I'd guess a lot of other DD motors are too. Select the 'show all' at the bottom of the motor dropdown list on the simulator.

If you're building your own swingarm that's an opportunity to mount a motor close to the pivot to reduce unsprung weight. Straight line chain drive is very efficient when both sprockets are large diameter.

[EDIT] Try the GRIN hub.

 

[multifrag]

The MXUS motors seemed very close and I'd guess a lot of other DD motors are too. Select the 'show all' at the bottom of the motor dropdown list on the simulator.

If you're building your own swingarm that's an opportunity to mount a motor close to the pivot to reduce unsprung weight. Straight line chain drive is very efficient when both sprockets are large diameter.

[EDIT] Try the GRIN hub.

Tested all motors on the simulator and it looks like Mxus 4504 or Leafmotor will be my my motor. They are similarly priced. The question is which one is better for Over 6 speed cassette.

 

[Triketech]

I don't know what model of trike you have; but regular operation at 50mph is probably outside of the design parameters for most trikes.

Even a good rigid frame trike like ICE or HPV tends to get skittish at speeds well below 50. KMX seems to be the most prevalent among the e-crowd but frankly they handle poorly to begin with. Speed needs long wheelbase and wide stance with low CG.

At speed front suspension needs to be tight and definitely a sway bar. HPV FS26 is my choice.

Theoretically if it takes 200 watts to go 25 MPH, it takes 800 watts to go 50 MPH. Theoretically anyway. I have a hunch 50 MPH will take more like 1500 watts. Volts are your friend with a hub motor. Weight better be your friend too.

 

[multifrag]

I don't know what model of trike you have; but regular operation at 50mph is probably outside of the design parameters for most trikes.

Even a good rigid frame trike like ICE or HPV tends to get skittish at speeds well below 50. KMX seems to be the most prevalent among the e-crowd but frankly they handle poorly to begin with. Speed needs long wheelbase and wide stance with low CG.

At speed front suspension needs to be tight and definitely a sway bar. HPV FS26 is my choice.

Theoretically if it takes 200 watts to go 25 MPH, it takes 800 watts to go 50 MPH. Theoretically anyway. I have a hunch 50 MPH will take more like 1500 watts. Volts are your friend with a hub motor. Weight better be your friend too.

Thanks for the tips on the frame. I will be building a custom frame. The battery will be 90V 45Ah and It looks like I will be getting a Leafmotor which has efficiency of about 90%. Long wheel base is not a problem. For the wide stance what do you think of splayed/tilted wheels. A 20KG battery should help for CG. Still in design stage, but will need to implement a sway bar. Any tips on tires/wheels? I', planing on running 20inch 32C at the front and 700x 32C at the back. 70 teeth or maybe a gear system at the front and 7 speed freewheel at the back to help the hub motor. It's more of a countryside project so I would love to enjoy the view and train my muscles

 

[Triketech]

For the wide stance what do you think of splayed/tilted wheels.

Any tips on tires/wheels?

Angled wheels won't help stability but will offset the contact patch plane; tire may have better grip and less wear in turns.

I run Schwalbe Big Apples.

 

[999zip999]

There's a dnp freewheel with 11t for high speed peddling and front 56t. Or ?

 

[multifrag]

For the wide stance what do you think of splayed/tilted wheels.

Any tips on tires/wheels?

Angled wheels won't help stability but will offset the contact patch plane; tire may have better grip and less wear in turns.

I run Schwalbe Big Apples.

Just finished reading ''Build Your Own Recumbent Trike'' By Rickey M. Horwitz. Now I understand the need for a complex steering at high speeds. The reason behind negative camber was for the better grip at cornering but on another thought I don't know if this will be useful as the majority of high speed roads are flat and don't have sharp turns. I think it's more important to get the wheels stay straight at high speeds and eliminate the bum steering. What caster angle would you suggest for 50Mph? I understand that the more the angle the more effort it will take to steer, but it should give it self-centering. Rickey M. Horwitz used 12 degrees, but I'm thinking I will need more. Not sure about the angle of Toe-in? Looked at your website and it's really helpful. Thank you

 

[multifrag]

There's a dnp freewheel with 11t for high speed peddling and front 56t. Or ?

I've contacted Leafbike about the possibility of freehub option as of right now the only image available of the leaf motor is with freewheel. They can make one with a freehub, but it would take 10 extra days to deliver. So, I think it's a win for people who need a lot of gears in addition to a motor

 

[llile]

You are trying to build the bike that I built!

See link in signature for complete detail on the build. I can send photos of things if you want.

Here are some tips:

1. Spokes break on trikes. All trikes with spokes break spokes, unless you design a complicated leaning trike, or don't go fast around corners. I helped work on the Keck Telescope, but a leaning trike is above my pay grade! I could not pull it off and gave up. I'm seriously considering machining a set of mag wheels for the trike front wheels, because of so many spoke problems. I'm using very heavy high quality spokes.

2. The simulator is probably underestimating your power requirements. That was my experience. Although I have a partial faring, I don't think my drag coefficient is as low as estimated earlier. Adding more faring last winter didn't change the efficiency at all. Whether from underestimating drag, or simply optimism, I was dissappointed in the efficiency in the real world.

3. Use motorcycle tires - DOT certified. DO NOT use bicycle tires at such high speeds. An 18" motorcycle rim is roughly equivalent to a 20" bike rim. Motorcycle rims spoke up to hub motors just fine, if you go with spokes.

4. I am running two Clyte HS4540 motors and two 40A controlers. Total amps for the pair of motors is limited to 35A by Cycle Analyst. At nominal 77V that's about 2700 Watts, or about 1350 per motor. I can go 35 MPH with that much power and it is wimpy on hills. I believe your estimates of power usage are optimistic.

5. The fastest I've gone is 45 MPH, and that scared me. 50 MPH puts a lot of stress on the bike. Especially front wheels on turns. I limit it to 35 MPH so that I don't end up as a grease smudge.

6. Consider a vehicle at least 48" width if you want to go at such speeds. You can check the cornering physics if you want, but that was the conclusion I came up with.

7. Get good brakes. Hydraulic disk brakes at a minimum. Consider motorcycle brakes. I am using bicycle disk brakes, and I regularly get them hot enough to warp, on downhill runs with stops.

8. Keep the batteries rearward. This helps with braking physics. You don't want to go ass-over-teacups when you stop.

 

[llile]

At 50 MPH you need a motorcycle license for your vehicle. To get a motorcycle inspected and licensed, it has to have 100% DOT certified motorcycle tires, and the proper lights at a minimum. You may have trouble finding a shop that will certify a homebuilt bike, YMMV. Laws may vary in your state. In my state you don't need motorcycle inspection if you are under 30 MPH and 3 HP. I figure I am close enough not to attract attention.

Re: gear ratio. Do the math, you'll be pedalling like a dentist's drill at 50MPH. I built an intermediate transmission, using an old 3 speed hub, that takes my 54T front and gears it up by 40%. In a recumbent you've got plenty of room for an intermediate transmission under the seat. I've also hacked them out of freewheels, however watch out, you can unscrew a freewheel if it is not cassette mounted.


Here is the current bike