Aluminum frame?

[Allenwrench]

How does everyone feel about an aluminum frame design?

 

[Karts of Kaos]

well, there"s nothing wrong with and aluminum frame but it would be alt more expensive and it could need a diferent design over steel. im no expert tho.

 

[7thofa2nd]

It sure would make the kart easier to carry around.

 

[Millwright]

Not all grades of aluminum are suitable for frame applications.
6061 T6 is typical frame alloy.

 

[Millwright]

Are you thinking a bolt together construction or welded? If welded, what process do you have available to you?

 

[Bansil]

7075 would be better for main rails and then use 6061 for bracing and such, 7075 has a lot more memory and doesnt stay bent like 6061 does, we started using 7075 for lower links on our rock buggies because of that

 

[JTSpeedDemon]

Aluminum will be harder to work with and less durable. That said, it will be much lighter than an equivalent steel frame. It will also be significantly more expensive. If you have the skills and money to try it, go for it! I'm all for unique and innovative go karts! Just know it will be much trickier and less durable than a steel frame. Also correct me if I'm wrong but isn't aluminum prone to cracking under stress? Or am I just thinking of cast aluminum rims and such?

 

[Bansil]

Well they use it to make planes the last 100 years as well boats, subs and cars....we designed will be plenty strong

 

[Millwright]

I have done a lot of "side" jobs, welding cracked aluminum trailers. They are very prone to cracking. I would never buy one. On the other hand, a light weight gokart will not be subjected to the same conditions. Having access to suitable alloys, I would go for an aluminum frame. If you can build it, you can fix it too If it did crack.
MIG with spool gun, super good and forgiving.
TIG , on a tubular frame project would be cumbersome, but doable.

 

[Millwright]

Pic from the last aluminum trailer frame I did.
Obviously been repaired before. This trailer had at least 5 similar breaks. But all were high stress and heavy load bearing locations.
As I said in previous post, aluminum might be fine for a gokart.
" it'll be fine" lol. For any cars and camera followers.

 

[Allenwrench]

Thank you all for your comments. The reason im considering aluminum is we race jr. faskarts on a oval track and we are fighting weight. We have to compete against 100 lbs kids with our “Bigger” driver. I’ve been in Aviation Maint for 30 years and worked with aluminum forever. I’m thinking 6061 is weldable or it’s 5052 one of them. I have a great friend who does all the welding at work. So if I design and cut out parts he will weld it. As far as T6 or T3 tempers, I might form in 0 condition and heat treat to T6. That would keep it less brittle. But I could be totally crazy too and way off. Thanks again.

 

[Millwright]

Allenwrench, just curious, are organized races not regulated on weight limits?
Or are you fighting to stay below the limit, whereas other light drivers might need to add weights to come up to the limit?
I'm working on my first kart right now, a bit of a tank in terms of weight. Probably in terms of handling too. Looking forwards to getting some performance data.
I'm thinking my second build will be minimalistic with emphasis on lite weight design and top speed.
Aluminum will most likely be part of the plan.

 

[Allenwrench]

Allenwrench, just curious, are organized races not regulated on weight limits?
Or are you fighting to stay below the limit, whereas other light drivers might need to add weights to come up to the limit?
I'm working on my first kart right now, a bit of a tank in terms of weight. Probably in terms of handling too. Looking forwards to getting some performance data.
I'm thinking my second build will be minimalistic with emphasis on lite weight design and top speed.
Aluminum will most likely be part of the plan.

You are correct sir. We have a minimum weight of 350 with driver. So the smaller ones are adding weight to race at 350. Whereas we are weighing in at 425. It’s always a struggle to compete.

 

[madprofessor]

Ever heard of a filigree truss? Unsure if that's just a Miami phrase, but it's something you used to see in Little Havana in the '80's on bicycles. Dankers Inn had his on a pole out front like a sign. Sign of pride, I guess?
It's literally a truss structure, but in very small gauge of round or square stock steel. Stuff the size of pencils piggybacked onto elaborate bicycle frames of anything from scrollwork to pop art, the trusses sometimes being art themselves. Great physical representations of very small scale engineering designed to support larger scale construction that's too weak on its own.
This is something that can be piggybacked on top of an inherently overstressed piece of material like a 5' long x 1" O.D. aluminum tube on a racing gokart frame. Soon as I saw "oval track" above this popped into mind, since there's no whoop-de-doos on those tracks.
A diagonal strut truss about 1" tall made from 1/8" aluminum rods tacked along the top of a weak frame rail can be super strong in the vertical plane and very light weight, as lighter frame materials can be used. And you'd have the only one out there.
Note: Couldn't find any filigree backbone trusses online, but here's a link to a modern frame that's actually a truss itself. Just interesting.
New twist in cycling: A truss bikers can trust | CompositesWorld

 

[Bansil]

Basically you have 2 types of chassis in everything, stiff or flexible.

General rule of this is ,if it has suspension make chassis stiff so suspension works.

If rigid chassis design the frame to flex to keep grip on track.

You run into neat issues with a long chassis say f550 or unimog etc, frame can flx 12" cab to bumper.
So you mount a stiff box that can't move onto like a 3 point mount with springs and retainers. So frame twists and camper doesnt

 

[Allenwrench]

Ever heard of a filigree truss? Unsure if that's just a Miami phrase, but it's something you used to see in Little Havana in the '80's on bicycles. Dankers Inn had his on a pole out front like a sign. Sign of pride, I guess?
It's literally a truss structure, but in very small gauge of round or square stock steel. Stuff the size of pencils piggybacked onto elaborate bicycle frames of anything from scrollwork to pop art, the trusses sometimes being art themselves. Great physical representations of very small scale engineering designed to support larger scale construction that's too weak on its own.
This is something that can be piggybacked on top of an inherently overstressed piece of material like a 5' long x 1" O.D. aluminum tube on a racing gokart frame. Soon as I saw "oval track" above this popped into mind, since there's no whoop-de-doos on those tracks.
A diagonal strut truss about 1" tall made from 1/8" aluminum rods tacked along the top of a weak frame rail can be super strong in the vertical plane and very light weight, as lighter frame materials can be used. And you'd have the only one out there.
Note: Couldn't find any filigree backbone trusses online, but here's a link to a modern frame that's actually a truss itself. Just interesting.
New twist in cycling: A truss bikers can trust | CompositesWorld

very interesting

 

[Allenwrench]

I have done a lot of "side" jobs, welding cracked aluminum trailers. They are very prone to cracking. I would never buy one. On the other hand, a light weight gokart will not be subjected to the same conditions. Having access to suitable alloys, I would go for an aluminum frame. If you can build it, you can fix it too If it did crack.
MIG with spool gun, super good and forgiving.
TIG , on a tubular frame project would be cumbersome, but doable.

You're are correct sir, it will crack. In aviation we find most of our cracks caused by corrosion. There are a few times caused by stress. but there is a huge difference in a Kart vs an Airplane that is up and down, pressure and no pressure all day.

 

[JTSpeedDemon]

You're are correct sir, it will crack. In aviation we find most of our cracks caused by corrosion. There are a few times caused by stress. but there is a huge difference in a Kart vs an Airplane that is up and down, pressure and no pressure all day.

Yeah that's what I thought, I work on old warbirds and stuff every weekend at the local air museum as an A&P apprentice, and if the kart is built to aircraft standards with the proper materials it should be fine.

 

[Bansil]

Doc and Fifi for the "Murica effect

 

[Allenwrench]

Yeah that's what I thought, I work on old warbirds and stuff every weekend at the local air museum as an A&P apprentice, and if the kart is built to aircraft standards with the proper materials it should be fine.

Very cool. I’m still in the planning process.
We’ll see