Building a hovercraft - need a stock exhaust and radiator

[dc4nomore]

I'm building a 3-person hovercraft with a couple guys I go to school with for our senior design project. We fully designed it from scratch and are in the building phase now.

If anyone has a stock exhaust or radiator sitting around, we would really appreciate a donation or cheap selling price. I think (?) the stock S2K exhaust is stainless so that is preferable but an exhaust or radiator from just about any car would work. We won't be able to use the exhaust directly, but we'll take the muffler and sections of the pipe and make a custom exhaust from that.

Approximately what the craft looks like now (as of about a week ago):



Below is what it will look like, minus an engine cover and other details.

Front view:



Back view:

[LagunaBlue]

Is that hovercraft going to be going fast enough (wind speed) to cool an engine with a radiator the size of an S2K one?

[dc4nomore]

I calculated the top speed to be 68.5 mph, with estimated cruise speed around 40 mph. The engine we're using is a 105 hp Mazda MX-3 four cylinder. We've also got the thrust fan placed behind the engine, so that should pull a lot of air through the engine compartment.

The topic of engine cooling is one of those things that definitely has not been figured out exactly. We'll just have to do what we can and see how it works. If we need more cooling, we'll have to modify later on.

[LagunaBlue]

Luckily you won't have any trouble finding a bigger radiator!

[dc4nomore]

Yeah that's true! Come on people, I know someone has something lying around!

[dc4nomore]

Too late suckas. A generous Hyundai Elantra and Toyota Corolla donated the radiator and muffler, respectively.

[AaronCompNetSys]

I just noticed the serious amount in weight of wood you've got going on there. Is there a reason you chose that instead of square steel tube with less structural supports?

[dc4nomore]

Yes there are several reasons. Although steel is generally stronger than wood, most of the same supports would still be needed because of the solid foundation required by the plywood shell, which is not incredibly strong by itself. Granted, there are some areas where wood is doubled up and the steel wouldn't be, but the steel would still weigh considerably more.

Ease of fabrication was also a consideration. Wood is much easier to work with than steel. Applying some glue and driving some screws is much easier than welding pieces together. Also, it would not be nearly as easy to fasten the 1/4" plywood shell to a steel frame.

There are probably more reasons but the last I'll list is cost. Wood is much cheaper than steel tubing. I think all that wood for the frame only cost us like $300.

As of that picture, the craft weighed around 305 lbs. Once finished, it will weigh 1000 to 1100 lbs with the engine and everything, and it will be able to carry another 550 lbs (the combined weight of the 3 of us building it).

[dc4nomore]

For anyone interested (or bored), we're having a Senior Exhibition at school this Friday the 20th, from 2-5 pm. The hovercraft, as well as all the other senior projects will be on display. It doesn't cost anything and there will probably be some pretty neat stuff. The address is 2220 Victory Parkway, Cincinnati, OH 45206.

Some more teaser pics:

[Newman18]

I love the handles to steer it lol.

[AaronCompNetSys]

Very cool updates. Keep them coming. Do you want me to move this to the Public Events forum so that teh Googlez indexes it, and the world can find your posts?

[dc4nomore]

^sure go for it.

I know aren't the handle bars gay! we should get some pink tassles to hang from them!

[dc4nomore]

Argh this thing still isn't completely finished but hopefully it will be soon. Bag skirt and fan still need installed to make it operational. Gauges, engine cover, and fan screen need finished to give it the final touch.

Picture of how it looked a couple weeks ago:

[Newman18]

You HAVE to take this to a monthly dinner meet. We can meet at the Bramble Patch if it'll help.

[AaronCompNetSys]

You can now link this to people outside of club members and they can read it without sign in.

[LagunaBlue]

Just to go on record:

If you don't put video of this thing flying on the board, I'm spreading nasty rumors all over the interwebz that it was a complete failure.

[dc4nomore]

You HAVE to take this to a monthly dinner meet. We can meet at the Bramble Patch if it'll help.

Yeah that sounds like a good idea. Just give me a month or so to get everything finished up. Progress will probably be a bit slower now that school is done. Plus I need to get a job!!

You can now link this to people outside of club members and they can read it without sign in.

Thanks Aaron.

Just to go on record:

If you don't put video of this thing flying on the board, I'm spreading nasty rumors all over the interwebz that it was a complete failure.

Lol ok I'll hook it up.

[SlowAnthony]

This thing is sick looking!!!

[LagunaBlue]

Hey Dave....speaking of this, where are the most current shots/vids?

I know you had a falling out with this, but we'd still like to see the outcome!

[dc4nomore]

Sorry I haven't updated this in awhile. I did get it fully working about a month ago, but shortly afterward, had quite a catastrophic failure.

I have a couple videos of me testing it but in the tests it did not fully lift up. I had to drill more holes in the back and adjust the pitch of the fan blades to get it to fully work. The first time it did work, I was so excited to test it out I figured I could get the video later. Unfortunately there was no later (yet).

What happened is the flywheel backed itself off and once it got loose enough, it completely broke off and ripped a couple mounting holes on the crankshaft off with it. As the flywheel bounced around the engine bay at 4000 rpm it severed the upper radiator hose and destroyed the radiator and slightly damaged the exhaust and the side of the craft. I suspect the poor quality of the custom-made bolts holding on the hub and flywheel as the cause of the failure. The threads were not cut very precisely and were very weak.

Unfortunately with the move and everything, I have not been able to work on repairing it. I basically need a new radiator and crankshaft and I'll be up and running again. I may swap in a new engine if I can get one at a junkyard because that would be easier than replacing the crankshaft.

Pics of when it was tested below. The blade pitch angle was reduced so the blades look a bit flatter now.

[LagunaBlue]

Nice work, man; it really looks about as professional as a back yard hovercraft can look!

I hope you get it working again one day.

[dc4nomore]

Thanks Shannon. Although there are some finishing touches planned which will make it look even better. One day...