Pulse jet Bike

[Stayt`ie]

Here we go I am half way there Dave



Pete

uummm, ok Pete, so your fabricating a seat, the ignition source is there (spark plug i sensor hole), fuel, well, uummm baked beans

[AuotonomousRX]

No use your imagination...... Reed Valve - Carby - Expansion chamber.....it's a Pulse Jet man!!!!

Pete

[AuotonomousRX]

How is the Cyclone up there Ron?

Pete

[Stayt`ie]

its ok Pete, just starting to slide past us now to the east, little bit of wind, plenty of rain with just over 4" so far today, everythings ok here,, what worries me is that there seems to have been quiet a bit of rain over Lake Buchanan,,

[AuotonomousRX]

I was thinking the same thing about Lake B.

Pete

[David Leikvold]

Thanks for the prompt Ian, I was never intending to develop rules that would have anyone using solid wheels on the salt at Speedweek. Years ago when Rosco McGlashan (a top bloke) was running Aussie Invader his V-shaped alloy wheels dug grooves in the salt and he had to keep moving his runs sideways so he didn't run over the ruts. Obviously that worked for him but would be no good at all for Speedweek. So that's why I mentioned using the 300 mpg Goodyears and then the 400 mph Mickey Thompson tyres, but only after an overdose of brave pills! No damage to the salt and no need to make changes to how we run Speedweek. The tyres keep the cars down to "reasonable" speeds and let's face it, who wouldn't want to at least try to go that fast?

I like the idea of the technical challenge of thrust vehicles, the knowledge is out there if we're prepared to look, we then have to apply that to a salt vehicle. I had in mind special construction only, pulse jets or gas turbines (I don't think solid fuel rockets would be controllable enough) and maybe even the same weight classes that electric vehicles use. Obviously the rules would evolve to suit the competitors, as they have for the wheel-driven classes, but I think for a start the existing tyre speed rules should apply, not everyone is going to be fast in the first year.

I know I've said it before but jets have a 50 year history at Bonneville, it's high time we started it here. Lake Gairdner needs to hear the roar of an afterburner again.

Cheers
Dave

P.S. Pete, you're on the right track

[ChrisACT]

(I don't think solid fuel rockets would be controllable enough)

Hybrid rockets can be throttled. You can use parafin wax as the fuel and oxygen or nitrous as the oxidiser.

It's completely stable (safer than petrol or methanol anyway) and there's no need for the complex turbo-pumps or scary cryogenic fuels required in liquid fuelled rockets.

You turn the oxidiser off and the fuel (wax) stops burning. If you really want to make sure it's out you just purge it with CO2 or Nitrogen when you pull the chute (which you will need 'cause your sitting in a damn rocket ).

[gidge348]

Maybe I should dig out one of my many UFO's (un-finished objects)

steam rocket.JPG (55.06 KiB) Viewed 9038 times

Saw this guy https://www.youtube.com/watch?v=CDDI5h8JQE0 going over 200mph in 2.5 seconds... with just hot water.

Got the details of his engine... 110L through a 75mm nozzle so I though 180L through 125mm nozzle would be more fun

Until it is heated it is only a water tank..... its basically a larger version of the engine in Evel knievel's rocket bike that he tried to jump the Grand Canyon.

Ian...

[David Leikvold]

Thanks Chris, I had never heard of the rockets you describe. So, rockets are in
Ian, that water rocket looks fantastic too. 200 mph in 2.5 seconds, with a bigger tank you could do 300 mph on the short course (ours, not Rob's, we have 100 miles of braking zone). These two ideas open up a world of possibilities. The best bit is they don't use fuel that can burn in a prang. Fantastic.

Can someone tell me how I go about submitting a rule change? I'm serious, it is becoming clear that we have a few members who would like to be among the first to build a thrust car (or even a bike).

Cheers
Dave

[ChrisACT]

Maybe I should dig out one of my many UFO's (un-finished objects)

Saw this guy https://www.youtube.com/watch?v=CDDI5h8JQE0 going over 200mph in 2.5 seconds... with just hot water.

Got the details of his engine... 110L through a 75mm nozzle so I though 180L through 125mm nozzle would be more fun

Until it is heated it is only a water tank..... its basically a larger version of the engine in Evel knievel's rocket bike that he tried to jump the Grand Canyon.

Ian...

I don't reckon that ratchet strap will hold.

[gidge348]

I don't reckon that ratchet strap will hold.

Ahhh where is your sense of adventure...

cyote.JPG (82.03 KiB) Viewed 8989 times

In all honesty though I think opening the flood gates to all types of "thrust Vehicles" would be a machine examiners nightmare.

These things are only as safe as the people handling them

Take for instance http://www.aeroconsystems.com/motors/lr64.htm these engines are available ......"online" they weigh about 30lbs and cost about $4000.

They will push a 250kg target drone to Mach 3....... and are throttle-able (see links).

The downside is they run on Hydrazine and Red Fuming Nitric acid, both of these will dissolve human flesh among a lot of other nasty things.

I think a lot of thought would need to go into what could be run, maybe a exhibition class or separate from the club????


Cheers Ian...

[David Leikvold]

Ian,

If we gave some serious thought to only allowing fuels that were at least as safe to handle as petrol or methanol we'd be OK. I agree that dangerous fuels like hydrazine and red fuming nitric acid shouldn't be used. I don't think hydrogen peroxide would be a good idea either. I was looking at videos of the paraffin wax and nitrous oxide hybrid rockets and learned that the reaction tends to blow out chunks of unburned wax. This would be unacceptable as they would need to be cleaned up. Apparently polyurethane is a better fuel when mixed with nitrous. I have no idea what the by-products of this combustion would be.

Perhaps if we allowed the use of jet fuel, petrol and steam as the first fuels and then considered other fuels as people suggested them or asked if they could use them. That would cover conventional jets, pulse jets and steam rockets. If the polyurethane burns cleanly it would be OK too. By cleanly I mean no toxic smoke or particles and no staining of the salt.
One thing we haven't mentioned yet is the use of propellers driven by any kind of motor. This would be simple enough and I would have no problem with that. That would generate some wild designs. Perhaps something like Stan Barrett's rocket car with a pair of variable pitch propellers at the back?

I also think we're not giving the potential builders their due. This thrust stuff will be foreign to most competitors and many wouldn't even be interested. Think how few people actually do over 200 mph. Those that would be interested in a thrust powered car or bike would probably be more likely to take the trouble to learn enough about the subject to have a decent go at it. Plus there's the expense, building one of these things from scratch is not for the faint-hearted or the light of wallet.

Cheers
Dave

[ChrisACT]

Pulsejets run great on propane.

Hybrid rockets fuelled by wax should only spit chunks if they're poorly designed. Getting the correct mix of oxidiser and fuel as well as the right sized nozzle enables the correct heat and pressure inside the combustion chamber which minimizes the fuel breaking up. However, you're right in that the plastic based fuels (like HDPE - High Density Polyethylene) don't have this problem.

Hydrogen Peroxide is next to impossible to get in any quantity since 9/11. It can also be tricky to handle. You don't want to make mistakes with that stuff. Ask the blokes who ran the Peroxide factory in Sweden that isn't there any more about it. KAABOOOOOOM!! http://www.portaltotheuniverse.org/blog ... iew/68331/

I think it's fair to say that nobody plans to strap themselves to a bomb. But we are all enthusiasts and some of us are probably crazy enough to try things we only have a passing knowledge of. We're curious. It's how the engineering mind learns.

However it's also fair to say that serious thrust propelled vehicles involve serious forces and require serious aerodynamics in order to stay pointing in the right direction.

When a wheel propelled vehicle gets "air" it is no longer being propelled. When a thrust propelled vehicle takes to the sky, it's called a plane.

Sure, at the lake we'd be limited by tyres but even still, I'd be prepared for some fairly clear cut rules for a thrust class (which I'd like to participate in one day).

[David Leikvold]

Thanks for that Chris, propane is on the list too. I think some people will be overly concerned about the perceived risk of explosions, so we should develop some rule variations to enhance spectator safety and driver safety in the cars with stronger (bulletproof or flak proof) or even double firewalls and definitely fully enclosed cockpits. The driver's area should be enclosed so that any flame that comes forward has to go a long way forward before it can get at the driver. Reduce onboard fuel to the amount needed for one run. Refuel after every run. Flak and fireproof blankets for fuel cells and propane cylinders or temperature/pressure relief valves. Bikes run tip sensors that shut off the engine at a preset lean angle so have the same fitted to thrust cars so that the thrust stops if the car gets airborne or really out of shape. I'd considered an automatic parachute release connected to it but that might not always be the best option. Better fire extinguisher systems with more capacity and extra nozzles. Fire detection systems that turn on the extinguishers in the burning area automatically, with a warning to the driver who would then pull the chute and shut off the fuel. Actually the warning light on the dashboard should automatically shut off the fuel flow. Parachutes that are designed to be downwind of a flame. And anything else that anyone can think of.

As for aerodynamic safety I think it would be sensible to copy the essence of the shape of cars we already know to be stable at high speeds. Small frontal area, very small floor pan width with minimal flat surface and rounded edges, a good weight balance front to rear, low ground clearance, low centre of gravity, thrust vectors that load the nose rather than lift it, small front winglets that can be quickly adjusted by the driver to generate more downforce and keep the nose down. They should also flip up if the nose lifts dramatically. Big four wheel disc brakes wouldn't hurt either.

Operational procedures would be barely different to the norm. I think it might be better for all their runs to be on the timed course, there is plenty of space and not many people. No spectators are allowed past the start line so the course would be safer than the short course which is closer to the pits.The most obvious difference would be that the staging lanes behind the car or bike would be cleared (or more correctly, held back and to one side) and I think starting the cars about 100m in front of the start line would eliminate any risk to spectators from initial start up and acceleration. Jets would not be allowed to use the afterburner, if fitted, until they were a reasonable distance from the start. At the start line my brother and I would warn spectators that the thrust engines were very loud, just in case they didn't know.

With tech inspection, the normal inspectors will have no trouble checking the features of thrust cars that are similar to ordinary cars. With a copy of the extra requirements to hand, they could also check those aspects of the car. Fuel tanks and lines would be identical, or very close to it. As for conventional jets we need someone with experience to check them. As I've said before, my brother Peter, the Chief Starter, is an engineer with 40 years experience at QANTAS. He could do that easily. With other propulsion systems I think other members of the thrust crews could check each other's work and educate the inspectors at the same time, although I suspect they would have been all over it as soon as it arrived on the salt. Something as simple as a pulse jet could be checked by any tech inspector. Ditto for a steam rocket. Hybrid rockets, not so much, but the soundness of a build is easy to see. If the car is shoddily made, the rocket should also be suspect. If the car is a work of art there is no reason to believe that that standard of excellence hasn't continued into the technology of the rocket. The owner / builder would be proud and happy to explain what the inspectors were looking at.

None of this amounts to a significant change in operating procedures. Speedweek runs very well with the enthusiastic cooperation of everyone there, I'm sure that would extend to thrust vehicles and their slightly different needs. And let's face it, people WOULD stop to watch them run.

Cheers
Dave

[ChrisACT]

This is the sort of thing I'd expect could be done at club level, reasonably safely without having to involve radical technology (or fuels) and the accompanying mega budget.


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