LocostUSA.com

I guess I should do a proper introduction of the project now that I have my pictures uploaded, hopefully this isn't too long winded...

The plan for the project was to build a no frills fun to drive toy. At my size (6'9" 230lbs) I don't fit into many of my ideal sports cars, not to mention the fact that I couldn't afford them anyway so I got fed up and decided to build my own. I've been drooling over Caterhams for years and came across the "the book" and thought that a locost would be the answer. I knew I wouldn't fit into a book frame and even the larger variants were questionable so I was pretty tentative. I started playing around with custom frame designs and came across the Norton Shrike. I liked the idea of a 3-wheeler because it took the minimalist approach even further than the Locost.

An overview of the project to date:

Donor bike, 84 GPz1100


Junkyard specials (Miata)


Cleaned up spindles and rebuilt calipers



I'm planning to use Hayabusa coilovers on all corners. The rear suspension will be a traditional bike swingarm actuating a dogbone rocker setup. Similar to the rear, the front will use a pullrod setup with the rocker being pulled by the upper a-arm. Hopefully this way the bike shocks will be operating in a fashion more in line with their original use, so the valving will hopefully be close. Please ignore the suspension mounts in the renderings, they are just kind of floating there till I figure out what I'm doing.


As I said above, I didn't trust my welding on the frame so I got my co-worker to do that part. Here is the day it came home.


The wheels as seen in the picture are 15x7 up front 15x8 in the back. I'm planning on running 205/50-15s in the front 225/50-15 in the back. My current though is to get Yokohama A048s all around? Considering the cost of these I'm starting to wonder if the DOT R tires are worth the money for mostly street driving?

The steering rack is out of an older 911 turbo, I was pretty amazed when I came across the dimensions and realized it was near perfect for my application, center pinion and all. The tie rods will need to be lengthened but such is life.


I'm currently working on finalizing the rear swingarm design.

It's mostly been reverse engineered from the donor, beefed up some and added the jackshaft to space out the chain for the wider wheel.

More to come as I get more done. Thanks for all of your comments, thats why I'm here. Hopefully you guys will ask the questions I'm not thinking of...

Besides the extra weight, did you consider a single-sided rear automotive hub from the rear of a fwd?

What about a belt final drive (less adjustment, quieter, no maintenance)?

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Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

I considered doing several different rear configurations including a single sided swingarm with an automotive hub. I settled on this because it's simpler, no need to add complexity to an easier proven design.

As far as a belt drive, no reason other than I have the sprocket from the bike and it's narrower packaging for a chain. Modern o-ring chains really are not too much maintenance and as far as noise goes, it'll be competing with wind and exhaust noise for my attention.

You may already know this, but here is some info on trike dynamics:

http://www.rqriley.com/3-wheel.htm

Looks like you,re on your way to a fine ride.

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It's my leg, Jack. The string's gone out of my leg.

I love the design, Myself I'd be tempted to throw a diff in there and make it a 4 wheeled design, would make a wonderfull track car. But I can understand the appeal of 3 wheels, if for nothing other than to be different.

your chassis design is very good, It may add some extra weight, but I'd consider welding in some 1/8" plate in the footwell to protect your legs from being punctured by the a-arms in an accident. Generally its considered a bad idea to have your legs between the a-arms, but there's really no theres really no other way to do it in your design without significantly extending your wheel base. so a little more weight for the sake of safety may be in order.

I've been contemplating an electric powered lightweight single seater for a while, I think a 4 wheeled version of your chassis would do nicely.

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Pictures of just a few of my projects

http://wrightspeed.com/x1.html Ar-i-el At-om with electric power. Runs 0-60 in 3.07 and 0-100 in 6.87.

wibiwo, yes I have seen that site but thank you for posting it. It's a good link for anyone thinking about heading the 3-wheeled route.

violentblue, Thanks for the compliments. I'd be lying if I said I haven't considered ditching the 3-wheel idea and hanging a differential off the back. It may happen down the road, we'll see...

Funny you should mention the 1/8" plate to keep the a-arms from becoming parts of the interior. I was thinking of posting this in the suspension section but I'll try here and see what people think of the idea. Mainly for the reason you suggested I've been trying to come up with a clean way to mount all the suspension components (a-arms, pull rod rocker and shock) to a single steel plate on each side which would in turn be mounted to the frame. This would

a) keep the outside parts, well...outside.
b) give me a relatively simple way to modify the suspension mounting locations, simply make a new plate instead of grinding brackets off of the tubes and hoping to not weaken the frame
c) if designed properly it could actually give a shear point for the suspension to dislocate in the event of a crash like F1 cars?

Any thoughts, ideas, suggestions?

Design the control arms to fail before the chassis. Layup a kevlar panel that will rivet to a flange on the perimeter tubes. The flange is inboard of the kevlar panel. The rivets a very small diameter and many compared to large and few. A metal strip is outboard of the kevlar panel to spread the load.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

I like the idea of the kevlar panel, much lighter, but I'm pretty weak in the area of composites. How would you go about the suspension mounts? Would a kevlar panel be able to handle the loads and fatigue from the suspension? Or did you mean it would just be a barrier to keep the suspension from penetrating?

Just as a barrier to prevent anything from penetrating the compartment, not structural. The attachment to the chassis must be strong and uniform to prevent the kevlar from ripping around the rivets so it is sandwiched around the edges. I'd use regular tubing structurally.

Check out the NTSB's application of a kevlar blanket on the Crown Vics that were exploding due to fuel tank penetration:

http://www.locostusa.com/forums/viewtopic.php?t=1813

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Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

wyked, what CAD program are you using?

SolidWorks

Hmm a kevlar panel would be good, but how thick should it be? It's tough to say exactly what you need for crash protection because crashes are so random. Have you ever seen A-arms with a third tube close to the pivots and parallel to the chassis? Basically they look more like a triangle... I've heard that third called an anti-intrusion bar before. It doesn't add much to unsprung weight either since it's close to the pivots.

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Matt Giles
www.gilesprojectcar.blogspot.com

It sounds like your describing a bar between the arm mounting flanges.

Bullet proof vests are going to liquid with a kevlar backing for less weight and more comfort.

I'm not sure if Kevlar 49 or 29 would be more appropriate. 49 has greater tensile strength. I don't think the velocity of the broken bits going into the interior is as high as a bullet. 49 is commonly available and relatively cheap, since it is used in boat and aircraft construction. I'd go with 3 layers of 5 oz, altering the layers by 45 degrees. The material and epoxy should cost about $150 for panels that are stronger than the attachments to the frame.

Check out how-to video:

http://www.jamestowndistributors.com/us ... lain+Weave

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

I think this is what Matt is referring to... an anti-spear bar as required in Champ Car (see arrow)...



It's about 1/2" tube that completes the triangle of the A-arm legs, making it far less likely one of those legs will penetrte the tub.

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http://www.SportsCarDesigner.com .... You want to design your own car... so go ahead. Sports Car Designer is the answer.