Please give me help here!!!!

[spacey_99]

I am making a r/c car with a pulsejet in it and i was wondering how to make it have throttle ability so i can accelerate and low down to a complete stop all by remote. Could you include simple instructions because i am kinda new at this and i dont know what some parts are called and what they do. Your help is appreciated. THX

[Rescyou]

You could use an rc-servo on a fuel needle valve. But also remember there is a point at which the p-jet will not function so it is impossible to throttle it from 0 to 100% unless you can add enough weight to the car so that at the minumum thrust ouput the car won't move or combine the decelleration with both thrust reduction and friction braking of some sort.

One other idea maybe to vector the p-jet thrust output, though that would probably be somewhat complicated and may mess with the internal workings of the jet.

I would assume that you can use the same fuel systems as you would on a internal combustion type model engine, but again remember there is a point where the jet just dies.

Interesting reading:

http://www.jetcatusa.com/PDFFiles/Instr ... nualV4.pdf


s.

[spacey_99]

Would i need to have it injected right into the combustion chamber or would i have to have the injector somwhere on the intake pipe. Where could i also find a good needle valve that would do this job well. and also is it posable to put a after burner on a pulsjet to boost the thrust or would it just make lots of fire out the end. THX

[Rescyou]

It appears you do not know the fundamentals with respect to this type of engine. You should have a good read through Kenneths site here as were as other sources around.

Best bet is to build you jet first so you get some experience in it's workings and then once you've gotten the hang of it, then start building it into a propulsion design.

Afterburners are severely inefficient as you are just dumping raw fuel in to the jet stream and in the case of te pulse-jet it probably would not work as the jet sucks and blows (wish I had a girlfriend like that..) and the fuel dumping would mess up the oscillation.

Myself, if I was ever to build a jet into RC model it would be a WIG/EKRANOPLAN... Move over Luke Skywalker.....

http://freespace.virgin.net/home.taylor/

http://www.du-groundeffect.com/video.html

http://www.ushuaia.com/emission19/videos_wm/video5.htm

s.

[Stephen H]

ohh get the "IS IT AMPHIBIOUS? YOU BET!! " its funny as

[Mike Everman]

Great links, Shane. I was going to mention the big Soviet beast I found in Jane's when I was a kid, and here's the video. Cooool! http://freespace.virgin.net/home.taylor/videos/km4.mpg

[Bruno Ogorelec]

I am hugely impressed by the Boeing Pelican. Hate to be the one to turn that beast that low off the ground (or sea), though.

[Hank]

Hello- As Rescyou stated, some basic knowledge on your part required.
A Google search with the printer full of paper is in order. Can you drill an accurately located hole?

A flying boat with extreme anhedral? I'll bet that twinkie was fun in a bank.

Anybody have any Heinkel 219 parts?

Hank

[Bruno Ogorelec]

A flying boat with extreme anhedral? I'll bet that twinkie was fun in a bank.

Hank, it is not a flying boat. It is a ground-effect (WIG) flyer, like those Russian behemoths on the Caspian Sea.

[Rescyou]

I've often wondered how those things would fair when foul weather sets in. That's probably one of the reasons they're not so mainstream as big-ass waves would pretty much put them out of action I would think.

S.

[Hank]

Hello- I see, Bruno. Ground effect. I have seen film footage of the Soviet-Era Acronoplan, another of such. It appears that the US developed their air cushion hovercraft while the Russians took on the weightier engineering proposition of developing a craft that would be capable of crossing deep-water at a high rate of speed. There was footage on BBC yesterday of some craft buzzing up the Volga using ground effect.

Hank

[Bruno Ogorelec]

I've often wondered how those things would fair when foul weather sets in. That's probably one of the reasons they're not so mainstream as big-ass waves would pretty much put them out of action I would think.

Shane, they can fly at higher altitudes, too, so it isn't such a big problem. The difference is that the lift/drag coefficient is much worse, so that higher altitude flight (out of ground effect) requires more power and means much worse fuel consumption.

Some aerodynamicists say that some early aircraft -- in particulat the spectacular Do X -- were in fact WIG machines and flew only in ground effect, their engiunes being inadequate to the task of pulling them out. For big machines, the ground effect can stretch pretty high and they can appear to fly normally while still being in ground effect. They just can't climb to any appreciable altitude.

Here's a wonderfully moody picture of Do X in flight.

[Mike Everman]

re: Dornier_Do_X.jpg

It's photos of projects like that that make be proud to be a human bean.

[tufty]

It appears that the US developed their air cushion hovercraft while ...

<pedant mode>

The - umm - who? I think you'll find that the hovercraft was invented and developed by Christopher Cockerell in the 1950s or so, who, after some limited UK gubmint funding, had to go it alone. I think you'll also find that Cockerell was merely following on from the 19th century inventor Sir John Thorneycraft (also from the UK) who first patented a 'ground effect vehicle' in 1870. So less of the attributions to the 'cousins', please ;-)

Cockerell's hovercraft related patents - http://v3.espacenet.com/results?sf=a&FI ... ER&EC=&IC=

More on Cockerell - http://www.google.com/search?q=christop ... 8&oe=UTF-8

</pedant mode>

Simon[/b]

[Bruno Ogorelec]

An interesting link to pulsejets here. In its ripe, commercial form, the hovercraft was developed largely by the British Saunders Roe company, which specialized in flying boats and helicopters before that. They were also the only major British developer and manufacturer of pulsejets and were at one point developing a pulsejet-powered helicopter.