The DYI-KART: Build log

[drex]

i think he is suggesting that he use the pipe and make his own nozzle for the motor , and put a cap on the other end. i have done this before only on a lot smaller scale.

[POLAND_SPUD]

DYI what body count do you predict ?

[drex]

for their to be a body count their needs to be bodies left.

[POLAND_SPUD]

yeah.... R.I.P. ---> REST IN PIECES...

now seriously - this is way to dangerous... I hope you gonna get someone to film it and to post it on youtube.com

[rp181]

I really dont think its gonna happen, so many people say there gonna do things, but they dont.

[DYI]

I really dont think its gonna happen, so many people say there gonna do things, but they dont

Ah, ye of little faith. We have the funding, we have the resources, we have the knowledge, and we have the determination.

Do you really think I'd be posting this thread if we hadn't already done tests to confirm feasibility? The only thing I've promised to build and subsequently failed to was the helium BB gun project. That won't happen again. [redacted] was just a pipe dream that was exposed before I was sure it was worth doing.

I won't be using premade pipe because buying the pipe and then attaching inlets and nozzles to it would consume almost as much budget as we have. Also, I wouldn't be very confident in 4" SCH 160 even being able to hold it.

And do I know that thrust in a hybrid rocket increases as the fuel burns? For God's sake, this isn't some half assed drunken idea we just randomly threw together. We do understand what we're doing here.

[drex]

i think you can do it, you seem to have all of the knowledge and skills necessary to do it

[DYI]

Update time!

Today I tested the ignition system we'll be using with a 2" x 8" motor, using gaseous oxygen. No nozzle was attached because of concerns about back-pressure on the oxy regulator, but the ignition performed flawlessly, and we got a nice roaring 4 foot long jet of flame when we cranked up the O₂.

The next step is to fill a several hundred ci tank with gaseous oxygen, and dump it through the engine using a ball valve, this time with a nozzle attached to the engine. In all likelihood, this will happen in a week or so.

The pressure vessel design has advanced once again. The new one involves schedule 160 6" steel pipe wrapped in carbon fibre with a layer of ceramic on the inside. The nozzle will likely end up being some sort of ceramic, or perhaps graphite. A combination of bolted and welded homemade fittings will be used for easy access to the guts of the engine.

Our calculations show that the current design will require ~13kg of paraffin, and roughly 130kg of N₂O for a run. Needless to say, we're seriously considering liquid oxygen right now. There are certainly hurdles involved in its use, but the decreased cost and weight might make up for them. The main challenge is to either prevent the LOX from warming up too much, or to build a pressure vessel that can survive 9000psi oxygen. We're leaning toward the former option for hopefully obvious reasons. Making the engine smaller was also considered, but that wouldn't really be in keeping with the spirit of the project.

The road we were originally planning to use proved unsuitable, and the new plan is to creat an ice track on a field in the winter with a large bank at the end to stop the missi... er... Kart at the end of the run.

More updates will follow as work progresses.

[SpudFarm]

sounds good DYI, you need to get a video up soon

[biggsauce]

DYI, had yall considered building a turbojet kart? It would allow for a bit more control and you could realistcally drive the kart with reasonalble safety.

I don't mean to knock yall's project, honestly I'm envious of your funding. This thing should be absolutely incredible to see in action. This is something average guys dream about...

[TurboSuper]

Heh, this sounds like an awesome project- strap rockets to a car and let it rip. It's like the ultimate Hot Wheels fantasy xD.

Mabye next time you should just point the cart straight up, then irregular terrain won't be an issue

[brogdenlaxmiddie]

DYI- Have you ever thought of working for NASA?

[starman]

For those who haven't seen it, some LOX fun from the early days of the internet....

How to light a grill in 2 seconds..

Just another plea for safety consciousness DYI....I know you're aware...for everyone else, LOX is not to be toyed with.

[DYI]

I'm thinking of doing another ignition test just to capture it on camera (after I get a working camera), but honestly, it isn't anything more than a very high temperature flamethrower at the moment. Nothing but tests of individual parts will be going on until we source a liquified oxidiser, and build the systems required to use it.

The real problem with LOX is keeping it below its critical point - cryogenic valves and such aren't really that hard to come by, it's the custom made storage chambers that cause the difficulties. We just need to keep it below the critical point for the time it takes to transfer it to the onboard tank from the Dewar flask it comes in. Precise temperature control will be needed here, there's no two ways about it. I'd greatly appreciate it if someone could come up with a phase diagram for O₂. Makes you kind of wonder when you can find a diagram for zirconium-oxygen tungstate (or something to that effect) and not for a widely used and vital chemical like oxygen...

This is something average guys dream about...

We're pretty much average guys. The only real difference here is ambition. I hate just dreaming about things - I have to figure out how to make them happen in real life, and then proceed to do so, often regardless of practicality.