Linner Strømlinet Vogn II

[Smurf]

So, you're basically the next generation Dave Edmunson? Keepin the local tradition alive!

If you can find an HMV Freeway around, that might give you some thinking material. I came across one in Moorhead several years ago, sitting in an old warehouse neglected. Hadn't been registered since 1992.

[Sven7]

Yes, I've seen a couple in person. Very spartan! I like them. They needed better aerodynamics, but are a fascinating starting point.


Cars and Coffee by Tyler Linner, Intergalactic Man of Mystery, on Flickr

This looks to be one with the top half removed. Component placement is not bad. From other photos, it appears to have swing-arm suspension up front.


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Dynamic Stability of Three-Wheeled Vehicles in Automotive-Type Applications

Thanks Neil. Perhaps I can stack them all in the nose to counter my body weight and control the Cg. This will take some more work.

The single front wheel layout naturally oversteers and the single rear wheel layout naturally understeers. Because some degree of understeer is preferred in consumer vehicles, the single rear wheel layout has the advantage with the lay driver.

I do not consider myself a "lay driver"- that seems to better suit the soccer mom in her Lexus. I can handle oversteer, but this makes up my mind-

A braking turn tends to destabilize a single front wheel vehicle, whereas an accelerating turn tends to destabilize a single rear wheel vehicle.

Braking and turning (emergency evasive maneuvers) are paramount. That is the one time that I absolutely, positively do not want to overturn the vehicle. Since it will have a very low power-to-weight ratio there should not be an issue with acceleration destabilization.

As far as rollover stability I think I am on the right track. Logically, a longer wheelbase will be more stable and so will a lower center of gravity. The third point they make is a wider front track for stability but since I am trying for a small frontal area (narrow track) the other two will take precedent.

I'm still trying to figure out what kind of angle the front wheels should be capable of without articulating the fender skirts in gentle turns. Something about tangent angles on circles...

I'm printing out a blueprint of the car in hopes of making another scale model. I have a small (~1/18) wooden model and a larger plaster rough of my earlier concept but want a 1/10 scale plaster mock-up to hold in my hand. This is almost as much a styling exercise as an engineering one for me, at least at this point, so the physical form is important. It has to look attractive, fast and professional. I don't want someone to walk up to it and say, "ohh, that's cute! What a nice toy," like they did of the Peel P50 and HMV Freeway.

Lots of rambling!

[Sven7]

Did a little work on a plaster model. About 20cm... really a good size for plaster. Good to have some alone time in the shop


Stromvogn Model by Tyler Linner, on Flickr


Stromvogn Model by Tyler Linner, on Flickr

[freebeard]

"About 20cm..." Is that 1/10 or 1/12 scale? Seems a little small for tuft testing.

[NeilBlanchard]

I think 1/12th scale is about right? The full size one would be 2.4m aka just under 8 feet.

[freebeard]

I see O.P. touched on that in his 30 Dec post. 1/10th scale would be good for R/C drivetrain parts. 1/12th is 1"/1' or dollhouse scale; so fences and mailboxes for the diorama.

[Sven7]

I got a little mixed up trying to scale it right but I think it's 1/20 scale. The finished car should be similar in length to a Mk1 Golf, although nearly half the width and a good 20cm shorter in height. Although, that sounds pretty big and those dimensions are apt to change.

This specific size was motivated by a desire for ease of sculpture. I can go to town on it with a foot long file with no problems. Big enough to show form but small enough to rough in the form in a few hours.

It would be ridiculously small for tuft testing. Maybe the full size buck will get a run, though I'm not sure how. Might have to lean on my intuition.

[redpoint5]

How does one register a vehicle like this for public roads?

I still have the frame from the electrathon car I built in highschool. The entire car with batteries weighed about 200lbs and had no suspension. The frame was entirely aluminum, perhaps 1"OD round tubing and a very beefy square tube aluminum axle. Modified bicycle wheels were used, and extra spokes were added to give lateral strength. Tires were aired up to 110psi. The motor and controller sat behind and below the driver as the seat was reclined. Since the car needed to turn more sharply than on public roads, the front axle was closer to the rear axle, and the drivers legs went over top of it. The 63lbs of allowable lead-acid battery was placed under and between the drivers legs to help balance the weight of the vehicle. Having the driver, motor, and controller in the rear made the front too light. Lexan was curved and used for the entire front/sides of the vehicle, with coroplast used in the rear.

With a 2hp motor, I managed to get the car up to 46mph on the 1/4mile oval running track before it became too unstable and was at the traction limit. I'd estimate it could do close to 55mph on a runway. Rollover was impossible due to the low center of gravity, although I saw it happen with other cars when they collide.

I second the HID headlight idea. Perhaps a single, 30w front bulb.

[freebeard]

redpoint5 -- If you built an Electrathon racer, do you know Mark Murphy? His BugE is essentially a street legal Electrathon car.

That said—anything that is at the limit of its handling at 45, and tops out at 55 on a track, might not be up to general road conditions. Remember, you have to re-engineer a Bonneville car for every 10mph gain.

I doubt you can tweak your way from 45mph to 65mph. Suspension would be a good place to start.

Look at it parked next to a golf cart. They're essentially a 'neighborhood vehicle'. Where those are allowed they are limited to a 35mph top speed IIRC.

[redpoint5]

Originally Posted by freebeard

redpoint5 -- If you built an Electrathon racer, do you know Mark Murphy? His BugE is essentially a street legal Electrathon car.

That said—anything that is at the limit of its handling at 45, and tops out at 55 on a track, might not be up to general road conditions. Remember, you have to re-engineer a Bonneville car for every 10mph gain.

I doubt you can tweak your way from 45mph to 65mph. Suspension would be a good place to start.

Look at it parked next to a golf cart. They're essentially a 'neighborhood vehicle'. Where those are allowed they are limited to a 35mph top speed IIRC.

The car I built wasn't actually for the Electrathon, but for a similar program in the Pacific Northwest sponsored by Portland General Electric. So no, I'm not acquainted with Mark. I built the car in 1999, and the race series continued for just a few years longer before getting dropped, possibly due to liability concerns.

There is no doubt the car would be unsuitable for the street. It was so low to the ground that small pebbles would scrape the belly pan. A speed bump would present a nearly insurmountable obstacle.

I just shared my experience to give a frame of reference. Your weight goals should be easily achievable, but then again I didn't have suspension. The aluminum frame was reasonably easy to MIG weld, and could very easily be picked up with one arm.

Where to place components isn't dependent only on where they fit in the design of the chassis, but weight distribution also needs to be considered. I would imagine having everything behind the driver would create a lot of understeer.

I also think 20hp is a little overkill if the design is efficient enough. Then again, I've never designed something capable of accelerating onto the freeway.