UAH Great Moonbuggy Race build topic

Ok so we are building a four wheel human power off-road vehicle for the NASA Great Moonbuggy Race and I figured I would share the build with y'all.

Here is a CAD model of the vehicle minus the seats.

Here are some pictures of the welds done by our awesome welder. It is an all aluminum frame so that is TIG welding.

The A-arms are a Rohacell foam core wrapped in Carbon Fiber with oil-impregnated bronze bushings.

The A-arms took 934lbs of compressive force to break them.

Our leaf spring is 30 layers of carbon fiber and has a spring rate of 60lbs/in.

And last but not least our differential. We created our own viscous type differential. Most of the parts (including of all the ones seen here) are fabricated by us. I will keep updating this thread as the build continues if people are interested.

sweet! where's the pedals?

nice work, this isnt exactly grassroots, but moonroots isnt too far off, so please keep updating!

Looks like a fun project. I wonder how many of the other teams have people on this board.

Why so much camber on the wheels (or is it just my bad eyes looking at the CAD drawing)? Do you have a good experienced cyclist on board?

If there's a diff in there hows the brake going to work?

Freakin awesome work though guys.

The entire differential housing spins so when the brakes are applied, the diff stops spinning and it stops the wheels.

We have a couple guys on the team that do a lot of cycling. The wheels have 6 degrees of camber which is majorly reduced from last year when the buggy had 14 degrees of camber. I don't know why we had so much last year.

I realise your buggy will never make it to the moon.. but two issues on your beautiful looking machine.

Most of the moon is covered in a fine layer of silt. Skinny tyres are just going to get stuck, even in the .16g that the moon manages to generate for gravity.

The moon also experiences WILD temperature swings. Boiling hot in the light of the sun, bitterly cold in the shade. How will Carbon fibre hold up to an almost 250 degrees celcius swing in temps?

Yup there is also the problem of pneumatic tires on the moon. In all reality, it is a race around an off-road coarse and it happens to be called the Great moonbuggy race. Oh carbon fiber can handle the swings but you would probably need to use high temp resin.

Edit: I finally joined the dork ranks!!!!!

I do have a question. Do you think arm restraints are a good idea on this buggy? Several teams have flipped in the past and a rider has put out there hand to catch themselves and destroyed their arms.

why not a roll bar?

Is the race in Huntsville or some other NASA site?

Thanks google. It is going to be in Huntsville in April.

It looks like the brake will only be braking one wheel. Why do you need a differential anyway? This is going to be offroad right?

No the brake will operating on both wheels. It is mounted to the differential case (which spins not the output shaft). The course is a mix of concrete and gravel. A roll bar would work possibly but the frame is aluminum and I figure the roll bar needs to be steel so adding one becomes difficult and the buggy also must fit in a 4'x4'x4' cube and ours folds which also adds difficulty to adding a roll bar.

an all aluminim buggy with almost no weight... I would go with an aluminum rollbar

Are you using mountain bike wheels? I've heard that spoked bike rims don't like sideloading. Possibly something to investigate. Mad props on the CF.

no they don't, not usually. on a spoked rim all the weight is "hung" from the top of the rim. The lower spokes do next to nothing. Cant it over at an angle, and the rim is going to want to move away from centreline of the hub, putting more pressure on the inside spokes than the outside.

We are using the Mavic D-Trax rims which are design to take the lateral loading. They are expensive though at about $250 a piece.

Some more bits of progress.

Random welding picture.

Yes those are friction dampers.

CNC cutting out the front uprights.

Just cause I thought it was a cool pic taken during the construction.

Nothing wrong with friction dampers. If they can work reasonably well on a 2000 + lb. old school hotrod, they'll work fine here. No apology needed.

As far as roll protection.. you really wont be going all that fast and I would think they would allow helmets and elbow pads if you are that worried. Think wrecking a bicycle in weight, its really not gonna hurt that much.

We have helmets but trying to catch 120-150lbs of buggy plus two riders with one arm equals bad things to the arm.