Need design review/build prep advice

[didjeffects]

Hey, first post! I've already learned a lot from this forum, cool spot.

I'm putting my very basic MIG welding skills to work and making my first vehicle, and I'm interested in getting everybody's opinions (I'm thick skinned) on my design and metal choices.

The vehicle is a single-seat, 2f1r three-wheeler. Donor vehicle is a Honda Elite 250 scooter. The idea is a single seat commuter, under 500lbs dry, that's fast under 50 and freeway capable, and enclosed. I'm going for simple/basic, but it's a good bet that I'm not there yet. And, I've gotta admit, I've got a little more money (just a little!) than sense - some decisions have been made to keep the project moving forward, and I'd started the build over Christmas before stopping for another redesign, but not before buying everybody's favorite chrome moly steel for my frame.

Soooo here's some jpegs from my 2D mockup:

http://www.metalmeet.com/photopost/showgallery.php?cat=500&ppuser=9230

http://www.metalmeet.com/photopost/data/500/frontview2D_shell.jpg http://www.metalmeet.com/photopost/data/500/frontview2D_v4_frame.jpg
http://www.metalmeet.com/photopost/data/500/medium/topview2D_shell.jpg
http://www.metalmeet.com/photopost/data/500/medium/topview2D_v4_frame.jpg
http://www.metalmeet.com/photopost/data/500/medium/sideview2D_shell.jpg


http://www.metalmeet.com/photopost/data/500/medium/sideview2D_v4_frame.jpg
The blue lines represent 1.5"x.095, and the green lines 1"x.083. These pics don't show the high sides, which are symetrical with one side welded in to the chassis and one side a door.

So what do you think? Any obvious trouble spots in my frame design? How about my tubing sizes? And the big one - I've already got the 4130, overkill for sure but I'm looking forward to using it, but is this a good project for it? I'm ok w/ the extra work involved. Closer to a kart than a car, will I appreciate the extra stiffness in this small frame, or will it make the street riding noticeably harsher than DOM? In a crash (with the high sides installed), with my low weight, I'm likely to bounce out of the way if the frame survives the initial impact, do you think a low weight vehicle makes the moly less likely to achieve cracking forces? And as designed, the frame will weigh in around 140lbs, is that acceptable for a vehicle this size?

Any and all opinions appreciated, thanks guys...

[Kerry Pinkerton]

Welcome (insert name) to MetalMeet.

Should be a neat project. I can't speak to the chassis question but tell us a little more about your plans for the body?

[Wray Schelin]

Hey, first post! I've already learned a lot from this forum, cool spot.

I'm putting my very basic MIG welding skills to work and making my first vehicle, and I'm interested in getting everybody's opinions (I'm thick skinned) on my design and metal choices.

The vehicle is a single-seat, 2f1r three-wheeler. Donor vehicle is a Honda Elite 250 scooter. The idea is a single seat commuter, under 500lbs dry, that's fast under 50 and freeway capable, and enclosed. I'm going for simple/basic, but it's a good bet that I'm not there yet. And, I've gotta admit, I've got a little more money (just a little!) than sense - some decisions have been made to keep the project moving forward, and I'd started the build over Christmas before stopping for another redesign, but not before buying everybody's favorite chrome moly steel for my frame.

Soooo here's some jpegs from my 2D mockup:

http://www.metalmeet.com/photopost/showgallery.php?cat=500&ppuser=9230

http://www.metalmeet.com/photopost/data/500/frontview2D_shell.jpg http://www.metalmeet.com/photopost/data/500/frontview2D_v4_frame.jpg
http://www.metalmeet.com/photopost/data/500/medium/topview2D_shell.jpg
http://www.metalmeet.com/photopost/data/500/medium/topview2D_v4_frame.jpg
http://www.metalmeet.com/photopost/data/500/medium/sideview2D_shell.jpg


http://www.metalmeet.com/photopost/data/500/medium/sideview2D_v4_frame.jpg
The blue lines represent 1.5"x.095, and the green lines 1"x.083. These pics don't show the high sides, which are symetrical with one side welded in to the chassis and one side a door.

So what do you think? Any obvious trouble spots in my frame design? How about my tubing sizes? And the big one - I've already got the 4130, overkill for sure but I'm looking forward to using it, but is this a good project for it? I'm ok w/ the extra work involved. Closer to a kart than a car, will I appreciate the extra stiffness in this small frame, or will it make the street riding noticeably harsher than DOM? In a crash (with the high sides installed), with my low weight, I'm likely to bounce out of the way if the frame survives the initial impact, do you think a low weight vehicle makes the moly less likely to achieve cracking forces? And as designed, the frame will weigh in around 140lbs, is that acceptable for a vehicle this size?

Any and all opinions appreciated, thanks guys...


Hello _____


A 3D view of the chassis would allow a better assessment
of it's strength and viability. From what I can see it looks like you have thought it through well.

The one element of the design I think is lacking is cockpit temperature, with that greenhouse glass the driver will lose weight and dehydrate quickly in the hot climes.:o

What is your intent with the overall design? Prototype, research?

I applaud your efforts and appreaciate the direction. Fuel savings and simplicity are two noble targets

[Chassisguy]

The basic structure looks good, but what kind of thought have you given to the steering. That could have a large affect on the design of the front of you frame.
Also another thing that concerns me is that you stated you have a mig welder and you are using 4130 moly tubing. That needs to be tig welded or gas welded. I know a lot of people think GAS weld moly? Well from what I understand that is what moly was designed to be welded with for aircraft, back when. If it was me though it would be Tigged.
Other than that it looks good. It would be nice to see in in 3D though.

[Boogiemanz1]

I don't think the 250 is going to do it for you. Scooters are available with much larger displacements now if it doesn't.

If you haven't already, check out Dave Nortons Shrike project... he has a lot of experience with it and his is on it's second incarnation..helpful guy WWW.Maxamatic.com (http://www.Maxamatic.com) the Maxamatic page has a lot of info on different attempts also.

Lots of good info on this page also WWW.rqriley.com (http://www.rqriley.com)..........


I worked on a production 3-wheeler once called a Freeway. It used an aircooled engine and snowmobile belt/clutch setup.

Good luck.............john

[didjeffects]

Thanks for the replies!

I'd like to do a 3D version, but I'm a Mac guy, anyone know of a super-basic modeler on the Mac? I do have a full scale 3D version in wood and plastic in a dome in my backyard...

Current plans for the body are either 1) Alucobond panels like Dave Norton uses at www.nortonshrike.com, or 2) fiberglass flat panel method. Alucobond is mainly for signs and covering buildings, it's a foam sandwich with .02 aluminum plates. Not structural, some sound dampening, easy to cut and do basic bends, give the vehicle a "low-poly" look. The fiberglass flat panel method involves laying out fiberglass on a flat, non-stick surface, then cutting shapes and securing them to a frame while they're still curing (you have a couple days) for smooth and light 2D curves. Much faster than laying-over-foam methods (I've been told), and you can glass the over the seams for a final finish.

Airflow is a big problem w/ the few enclosed 3ws out there, and with my wraparound lexan cockpit I'm asking for heat buildup. My donor is water cooled, so that'll help. I'm planning ins and outs in several spots for driver comfort - intakes on either side of the headlight will feed fan supported vents inside, the little triangle windows up front will open forward, the short diagonal windows on either side roll down, the top opens & can be removed, and the trapezoid in the back is a window just behind my head.

Steering is hard from a sourcing parts standpoint. The trapezoid where the feet land in the side view will be filled but the design is in flux. I'm looking I have a wish list - center steer, 2.5 turns, 3" of travel. The $130 sandrail racks have a lot of play in them and fast ratios, Stilletto jr dragster racks are better but made but still pretty fast for street. Flaming River will make me exactly what I want for $700, which feels pretty expensive now, but maybe less so when I get tired of searching and need to move forward. My original budget was $4000, which I've just recently reached, having everything but steering components, fuel cell, and material for the shell. Anyone have a favorite off-the-shelf unit for center applications?

Thanks for the tips on working with moly - I've got a friend's MIG settup, but I'm sure I know someone with gas rigs, I'll look into it. Might be a good excuse for a TIG class, too...

thanks,
-=cam

[Boogiemanz1]

I was told that Porche makes a center steer rack.............I had planned on a Speedway Auto rack for dragster or probably the same you quoted for sandrail.............john

[didjeffects]

Yeah, I'm not certain about my donor choice power wise, but there are some good signs. The Elite weighs about 300lb and takes hills no problem riding 2-up. My projected weight is about 380lbs before the high sides/door & shell are added, so I'll be under 500lbs, as far under as I can manage. And I'm not the first to use this engine, English-made Isetta and Messershmitt (http://www.tri-techautocraft.co.uk) replicas use the same engine and they're 600-650lb 2-seaters (tho their designs limit their top speed in other ways). I've made basic mods like a kevlar belt and updated roller weights and a sportbike exhaust, so in scooter form the donor runs strong. If it doesn't work out I'll find a 400cc scoot - the smaller Burgman claims the same mpg as the Elite...

What did you do on the Freeway? What did you think of the finished product?

thanks,
-=cam

[Chassisguy]

Check with Unisteer (http://unisteer.com) . They custom make racks also. I have been told that they are a little better priced than Flamming River. You may want to concider a steering box design.

[Boogiemanz1]

Cam, I had a motorcycle shop and the town millionair wanted his toy fixed. It was powered by a rotax, which ran good, but nothing worked on the thing. I rewired most of it (looked like Joe Lucas had been there first) fixed the charging system, and tuned it up. He promptly went out and broke a belt on the drive. This was pre-internet and we could not find a belt. He got in his airplane and flew up north somewhere and brought back a belt. With the belt installed it seemed to be a decent little around town runner. Crosswinds played havoc with it at speed.......way too hot inside for the Oklahoma summer......He sold it to someone in another state.......

I'm more intrested in a T-rex in vintage style bodywork with plenty of engine...............:grin: .....................john

[Da Tinman]

If ya plan to use Moly tubing I wouldn't Mig it,, tubing will be very britle around the welds. In fact we are not allowed to Mig anything but mild steel.
we don't even do that,, our mig is used to tack everything together. and not much else

[mrkarl]

then i assume you TIG to finish?

[Da Tinman]

Yeah we Tig just about everything.

I have seen a few gas welded dragsters, an "old timer" who builds nostalgia stuff has been gas welding tubing forever. I don't know how a it will perform in a crash, although vibration doesn't seem to bother them, so I assume its just as strong. At least I hope so, for his customers sake.

[didjeffects]

Thanks everybody for the good advice. I don't have access to a TIG settup, but I can use a friend's gas welder. So now I'm thinking tack my moly frame together with gas, then find a certified welder to finish up with a TIG (I was gonna have to find someone to inspect my welds anyway...). Seems like this way I get to do all the cutting and measuring that I want to do myself while saving a little on somebody elses shop time, and wind up with better welds. Good idea?

-=cam

[Chassisguy]

A good friend of mine who is a metalurgest (I think thats how it is spelled) told me that moly materials were developed and designed to be welded with gas. We both believe the reason for most racing sanctioning bodies to require the tig welded process is so that it would discurage none experiened individuals from building these chassis. In other words to help protect the average joe. Just like not being alowed to stick weld MS. Anyone one can by a buzz box, and throw some weld at a piece of metal, but unless you know what you are doing its not going to be a pure weld and hold.

[ants2au]

What materials can we stick weld? from the below, look like we can't use stick on anything. MS (assuming = mild steel) seems to be the lowest common material

Can stick be used on DOM?
Would there be a list of what materials can be welded with what method?

Cheers, Anthony


A good friend of mine who is a metalurgest (I think thats how it is spelled) told me that moly materials were developed and designed to be welded with gas. We both believe the reason for most racing sanctioning bodies to require the tig welded process is so that it would discurage none experiened individuals from building these chassis. In other words to help protect the average joe. Just like not being alowed to stick weld MS. Anyone one can by a buzz box, and throw some weld at a piece of metal, but unless you know what you are doing its not going to be a pure weld and hold.

[Chassisguy]

If you are bulidin a car to race, most, if not all will not allow it to be stick welded. For your own use and such out of the relm of racing you can stick weld what ever you are capable of welding. I do a some repairs on wreckers, farm equipment and such and still use my stick for those. But when it comes to a race car it is either migged or tigged.

[rsanter]

I have helped build a couple of 3 wheel type cars for some projects I was in.

in one car we were competing for high milage and weight was a big issue. the body was vacume formed over a foam buck we made. we stacked up insulating foam and carved it to the shape we wanted then used bondo to fine tune the shape. the vacume former worked great. we gave the body structure with thin aluminum strips bent into an L like angke iron and then used a shrinker/strecher to curve the pieces to fit the body. it worked geat.

the other method we used on a larger 2 person 3 wheel project was to build the foam buck and lay the fibergalss on the buck. once all was preped and filled to our satisfaction we riped the foam out and had a one piece body shell including the door jams and lip for the hood opening. worked wel but needed alot of work to get the body shape smooth.

for the larger 2 person car we used mustang II front suspension and the rear was a pure theft of the back of a 750 motorcycle. reverse was accomplished with a spare flexplate and starter motor from a donar vehicle.

[Boogiemanz1]

The 2 person car sounds a lot like a Tri-Magnum....except for the Mustang II front end................john