Electric Messerschmitt project

Joined
Jan 24, 2009
Messages
15
Location
Roswell, GA
I was online shopping for ideas on how to convert my (non-running) 1955 Messerschmitt KR200 to electric when I stumbled upon the Micro-cars thread and realized that I wasn't the only one with the same idea.

For reference, the finished car will weigh about 500 lbs., less the original 200 cc engine, plus batteries, motor & 2 adult passengers. See also Michaelplogue's photos and helpful CAD renderings in the Micro-Cars thread.

Wishful thinking: Quick acceleration, maybe 50 mph top end (60 perhaps?), decent range.

With limited space, I like the idea of using a 10-inch hub motor on the rear wheel. Not without problems, though.

I had wanted to avoid cluttering the cabin with batteries and excess electronics, but after seeing Michael's great CAD renderings I may reconsider. In a perfect world, I'd prefer to keep all the hardware in the rear or under the dash.

Lots of options, but would rather get it right the first time. Any suggestions?
 
The motor part is easy. there are plenty of Chinese electric scooters out there, many not imported but it shouldn't be hard to find a heavy duty rear hub motor. I've seen 4Kwatt hub motors on ebay

Range = batteries, so lots and lots of A123 or equivilent LiFePO4. Or if thats not in the budget, a salvaged Prius battery?
 
For comparison, the Citicar had a 3hp motor and eight 6V golfcart batteries. It could go about 40mph for about 15mi. Much longer ranges (2x) are possible at slower speeds.

The KR has much better aero, weighs less and better motors are available now.

Your goals may be achievable, but only by not using lead batteries.
 
Here are some elvation shots of the model. The grid marks are 12" - though I can't vouch that the scale is perfect. I had to scale the model based on dimentions of the KR found on the internet. Hopefully the model is fairly accurate - from what I've seen in photos on the internet, it seems relatively close.

(depending on your screen resolution, it may appear that the images are cut off on the side - just right clic and hit view, or save them.)

KR200Side.jpg



KR200Top.jpg



KR200Front.jpg



Messerschmidtt.jpg



The batteries I used for the layout above are the ones from here: http://www.cloudelectric.com/product_p/ba-lb-100-3.2.htm

I think that by spreading then out in the passenger compartment, the weight distribution overall is much better than trying to stuff everything in the engine compartment - with all of the weight on the single rear wheel..

I've got 24 of these in there, which could give you either 48V 200AH, or 72V 100Ah (Or switchable between both). You'd need a good BMS for these - you could use the Open Source BMS kit that was developed by a couple of guys here on the forum, or something like the ones below (which are specifically designed for this style of battery cells).

Master: http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=4803
BMS-master-alone.jpg


Slave (one on each cell): http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=4807
BMS-cell.jpg


The motor I was considering using is an AC induction motor (probably the AC-12 model, as it can run both the 48 and 72 volts). It would depend on if this particular motor can run full time CW (so it can be mounted on the wishbone support). If not, then I'd probably opt to go with a D&D ES-15A-6 48-72 VDC 10hp single-shaft motor: http://www.electricvehiclesusa.com/product_p/mo-es-15a-6.htm
 
Space is really scarce in the cabin. There is no usable space under the floor, and raising the floor is not practical.

Here are some useful dimensions:

Under the rear seat is a space approx 26" W X 10" D X 4" H.

Passengers are most comfortable with their legs extended alongside the driver, so you have a choice: Either stack batteries along the sides and eliminate that option, or fill the footwell in front of the rear seat. If you want to carry a passenger you can't do both. Useful space in the footwell is about 25" W X 10" D X 3" high. There is about 8" of legroom between the front and rear seats (and the rear seat is about 11" D).

Messerschmittinterior2.jpg


Next to the driver's seat, the distance from the front corner of the driver's seat to the side wall is 6", from the back corner is 8" (the driver's seat is narrower at the rear and the side wall bows out at that point). The door sill is 9" H at the front corner of the driver's seat and 12" H at the rear.

Messerschmittinterior1.jpg


By the way, within the engine compartment, the upper cross member is 28.5" W, and there is 18" from the bottom of the firewall to the bottom edge of the upper cross member. There is 13.5" between the firewall and the center of the driveshaft.
Messerschmittrear2.jpg

Messerschmittrear.jpg

Messerschmittrear6.jpg

Messerscmittrear5.jpg
 
Thanks for the pics! It looks like it would be relatively easy to completely replace the entire rear end with something fully customized. Do you have a shot of where the motor connects to the drive shaft assembly?
 
Very cool.

Is there any room in front of the driver?
I have very little experience with Messerschmidts but have built a few trikes with 2 front wheels.
And what makes them handle well is weight between the 2 front wheels.

Eliminating that rear triangle with some updated (maybe monoshock motorcycle?) piece would clearly be the best way to go.

Cheers,
Rob

(BTW: The Honda Insight was inspired in part when Honda was trying to build a new NSX and wanted to locate the motor in the floor! )
 
You are absolutely correct. The rear end is held on with three bolts and is easily removable. My original plan was to replace the rear end with a rear clip from a 1987 Honda Elite 250 scooter, thereby replacing the old 2-stroke with a 4-stroke and a CVT. I even went so far as to acquire two donor bikes, cut one down and bolted it on, but I abandoned the project for several reasons:

1. I was never convinced that the rear wheel of the bike was perfectly aligned with the center line of the car, and I had not allowed for a convenient way to shim it into alignment;
2. Air cooled (orig.) vs water cooled (replacement). Placing the radiator proved to be trickier than anticipated.
3. Final nail in coffin: The geometry of the replacement just didn't seem as rigid as the original steel triangle framework. The more I visualized a catastrophic failure at 50 mph with me rolling down the road in a steel box, the less I liked the idea. When gas went over $4 and Atlanta had none at all this fall, I rebuilt the parts bike and have been riding it!

If I could find a sufficiently beefy Chinese scooter I might consider revisiting the "transplant" approach. A successful operation would entail several key planning items:
1. Strong, yet adjustable attachment method. Perhaps some sort of a jig which would allow washers to be inserted to make incremental adjustments.
2. Adequate suspension. In all likelihood, the springs would need to be upsized.
3. Enough spunk to push 800-1000 lbs at a good clip. The original car could go 60+ (in theory, on a good day). I'd hate to settle for a top end less than 50.
4. Suspension geometry on scooters tends to put the springs high above the rear wheel. The framework still needs to fit inside the rear cowl of the original car, which tapers at the rear. I really don't want to add extensive body work to my to-do list.

Nevertheless, the right donor bike could simplify the project and possibly help keep the costs down.

As far as space in front, there is room under the dash for some electronic components and perhaps a battery pack on either side of the driver's footwell. In terms of scale, think "bumpercar."

Michael, in looking over your battery placement in the passenger compartment, I recognized a potential problem. On Cloud Electric's web site I saw this comment: "A properly ventilated Li pack will settle in at about 114F." If you pack the passenger space with all the batteries, it will feel like a convection oven in there! That could be a rude surprise the first time you charge up your system.

As you requested, I've taken some pictures of the linkage point between the original engine and drive train.
Messerschmittlinkage2.jpg

Messerschmittlinkage.jpg
 
Here's a picture of the Honda Scooter I used for my first attempt at converting the 'Schmitt. Close, but no cigar.

Nevertheless, I have continued to flirt with the idea of using this framework (with some modifications), to mount a hub motor on.
ChoppedScooter.jpg
 
Thanks for the pics! Looks just like I would have to completely re-configure the back drive shaft and replace it with a customized jack shaft - not a huge problem I wouldn't think. I think you might have the right idea in just building a rig that will accept a donor swing arm off a standard motorcycle/scooter.

One way to make it adjustable latterly would be to weld some offset bars (parallel to to top and bottom existing mounting bars) and make a sort of 'C' clamp on your arm rig that would clamp onto these - allowing you to slide it left or right.

Something like this??

SWINGARM.jpg
 
Michael-

It's not quite the right-to-left adjustment that I'm concerned about, but instead whether the rear wheel is pointing straight ahead (and exactly parallel to the front tires). With a short wheelbase three-wheeler, even the slightest deviation will cause the vehicle to "crab-walk" down the highway, especially at higher speeds.

Even if the "arm rig" is designed to be perfectly symmetrical (i.e., square), and actually gets built that way, it still would probably need some fine tuning. For instance, if the cross beam at the rear end of the car is not exactly perpendicular to the center line, a perfectly square arm rig would be pointing slightly off-center.
 
Ah.... Well, with a regular motorcycle swing arm, you usually have a bolt adjustment that helps align the wheel axle, allowing you to "true' the wheel straight.

Not good pictures, but each side adjusts independently.

belt_adjust_measure.jpg


wheelalign4.jpg
 
Electro-Schmitt said:
. . . As you requested, I've taken some pictures of the linkage point between the original engine and drive train.
I guess it's not much wonder that the Messerschmitt resembles aircraft work more than typical automobile work in 1952.
Thanks for the pix
Sweet project. Good luck.
 
Electro-Schmitt said:
Michael, in looking over your battery placement in the passenger compartment, I recognized a potential problem. On Cloud Electric's web site I saw this comment: "A properly ventilated Li pack will settle in at about 114F." If you pack the passenger space with all the batteries, it will feel like a convection oven in there! That could be a rude surprise the first time you charge up your system.

What I had been thinking of would be to build boxes that would completely cover the cells (having the appearance of chair arms). The box would be ventilated from the bottom and out the back into the engine compartment. During charging, one could have a fan setup that runs during charging (powered directly from the charger via DC-DC converter). You would just need to be sure you had sufficient gaps between the cells to allow for good air flow.
 
michaelplogue said:
What I had been thinking of would be to build boxes that would completely cover the cells (having the appearance of chair arms). The box would be ventilated from the bottom and out the back into the engine compartment. During charging, one could have a fan setup that runs during charging (powered directly from the charger via DC-DC converter). You would just need to be sure you had sufficient gaps between the cells to allow for good air flow.

Certainly doable, but as you add a layer of insulation + space for airflow, the capacity of your boxes becomes limited. Of course, even putting half the batteries up front and the other half in the engine compartment would provide better weight distribution than stacking 'em all in one spot. So it may be worth the additional complication.

As for the adjustable bolt on the motorcycle swing arm, unfortunately that feature is not present on my 80's era Honda Elite scooters. The axle simply goes through a hole with no ability to adjust the orientation. Since the Chinese purchased Honda's old tooling to build scooters (including many still in production), it would not surprise me if that feature remains absent on the Chinese knock-offs, too.

Nobody ever said it was going to be easy!
 
Hi,

FrankG said:
Electro-Schmitt,

I know I'm chiming in a little late with a suggestion like this, but...

Does the KR-200 have any hope of being ressurected in it's original condition, if so I think those units have tremendous re-sale value, which could fund a killer replica that could be proportioned and designed to be everything that you could ever want...

I was about to post a similar suggestion. Maybe you could sell it for enough to pay for a replica kit plus a Lithium Battery Pack :D
http://www.modernmicrocars.co.uk/prices.html
All interesting Microcars and parts always wanted.

Also:
Please note that it is now possible to build a messerschmitt without using any original donor parts.

Maybe they have some rear suspension parts that would work better with the electric motor than the original. Maybe the original parts are worth more to a collector than modern replacement parts.
 
I've wrestled with the idea of doing a "real" restoration. The car is pretty complete, although it's been badly bastardized over the years. A good quality restoration would involve a bigger investment in time, money and effort than I'm willing to invest. At this point I'm really sold on the idea of electrifying the car. Once it's up and running I'll likely sell of any excess hardware, but I doubt I can generate enough to pay for a whole lot of electronic gizmos that way.

I'm also all too aware of people who spend $25K (or more) to restore (or customize) a car only to end up with a really nice vehicle worth $15K. Of course, investing in a LiFePO4 system potentially involves the same peril. :D

Regarding the "Luggage rack" system, I have thought about that. I wouldn't want to mount heavy batteries that high, but in a pinch that might be a good place to stash some electronic components. In addition to making the vehicle top heavy, the rear body section where the luggage rack is mounted is basically a self-supporting piece of sheet metal (probably not strong enough to hold a battery pack), and needs to be able to pivot upward to give access to the engine compartment.

I've also thought about putting some batteries in a small teardrop-type motorcycle trailer. As long as the trailer is not too heavy, it would probably not adversely affect handling.
 
Electro-Schmitt said:
I've also thought about putting some batteries in a small teardrop-type motorcycle trailer. As long as the trailer is not too heavy, it would probably not adversely affect handling.
That gets my vote... perhaps a "bob" style.
 
Hi,

Electro-Schmitt said:
I've wrestled with the idea of doing a "real" restoration. The car is pretty complete, although it's been badly bastardized over the years. A good quality restoration would involve a bigger investment in time, money and effort than I'm willing to invest. At this point I'm really sold on the idea of electrifying the car. Once it's up and running I'll likely sell of any excess hardware, but I doubt I can generate enough to pay for a whole lot of electronic gizmos that way.

I'm also all too aware of people who spend $25K (or more) to restore (or customize) a car only to end up with a really nice vehicle worth $15K. Of course, investing in a LiFePO4 system potentially involves the same peril. :D

I wouldn't even consider 'doing a "real" restoration". What I would do is find out how much its worth as is to collectors.
 
Frank-

Instead of Goldwing-type storage units, I could use cylindrical cases painted to look like jet engines.

Tacky? Yes. Ridiculous? Certainly!

Fun? Well, yeah, that, too.
 
You might have some interest in the work I'm doing on a high power Hub motor (Motorcycle class Hub motor)

http://endless-sphere.com/forums/viewtopic.php?f=10&t=7718

Mark
 
You probably vetoed this already, but if you don't mind making it a single seater (ditching the passenger seat) you would have a lot more space for batteries. Just in case you didn't think of it :wink:
 
paultrafalgar said:
You probably vetoed this already, but if you don't mind making it a single seater (ditching the passenger seat) you would have a lot more space for batteries.

My 12-year-old son would definitely exercise his veto power on that suggestion!

In all seriousness, though, I want to retain the two-passenger capacity of the vehicle (or at least 1 passenger vehicle plus adequate cargo space). To me, it's preferable to tackle the problem of shoehorning all the necessary gear into the available space than to sacrifice the utility of the vehicle.
 
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