Search found 39 matches

by Bruce Simpson
Thu Jul 29, 2010 2:04 am
Forum: Valveless pulsejet forum
Topic: homemade jet bathtub that was powered by a BBQ propane tank
Replies: 42
Views: 16581

Re: homemade jet bathtub that was powered by a BBQ propane tank

My experience with pulsejet powered boats consists of: pulsejet powered kayak Pulsejet powered boat (junkyard wars) Basically pulsejets are not much good with displacement hulls but if you could get a decent hull up on the plane they'd be great. Still thinking of making another one with a stepped hu...
by Bruce Simpson
Tue Jul 20, 2010 12:26 am
Forum: Valveless pulsejet forum
Topic: Rainy Day Project: Lady Anne Rev 09
Replies: 12
Views: 4059

Re: Rainy Day Project: Lady Anne Rev 09

Larry, get one of the little keychain fob video cameras from ebay -- they're about $15 and take some *amazingly* good video and stills. You then download them directly onto your computer by simply plugging them in a USB port and copying the relevant video files onto your hard drive. Then you can upl...
by Bruce Simpson
Tue Jul 20, 2010 12:22 am
Forum: Valved pulsejet forum
Topic: problems starting a lpg/propane pj
Replies: 22
Views: 5879

Re: problems starting a lpg/propane pj

The startup sequence varies depending on the design. The ECU I built for a liquid-fueled valveless engine starts with spark, adds air, adds fuel, listens for combustion (vibration sensor) and if the engine doesn't sustain, shuts off gas, waits (to allow the air to flush the chamber) then resequences...
by Bruce Simpson
Wed Jul 14, 2010 11:46 pm
Forum: Valveless pulsejet forum
Topic: “Aerodynamic valve” for valveless pulsejet.
Replies: 8
Views: 4898

Re: “Aerodynamic valve” for valveless pulsejet.

Thrust and pressure (for a given masflow) are inextricably linked so the softness of the tesla valveless conduit would also affect the ability to drive a turbine or other means of converting pressure to torque. Besides which, pulsejets may have many positive attributes (simplicity, low cost etc) but...
by Bruce Simpson
Mon Jul 12, 2010 9:11 am
Forum: Valveless pulsejet forum
Topic: “Aerodynamic valve” for valveless pulsejet.
Replies: 8
Views: 4898

Re: “Aerodynamic valve” for valveless pulsejet.

Tesla's valve is too soft to be of any use in a pulsejet. By "soft", I mean that it accepts a lot of incoming flow, even if only a little flow makes it to the outlet. This effectively reduces the combustion pressures in side the engine and so reduces efflux velocities, hence thrust. I played around ...
by Bruce Simpson
Fri Jul 09, 2010 3:42 am
Forum: Valved pulsejet forum
Topic: problems starting a lpg/propane pj
Replies: 22
Views: 5879

Re: problems starting a lpg/propane pj

Not enough gas for a start and, lighting the gas at the tailpipe is not a very good way to get an engine going -- it's much better to have the ignition source in the combustion chamber (a spark-plug, sparkler or what-ever). I suspect that if you wind up the gas-flow you'll still have problems gettin...
by Bruce Simpson
Thu Jul 08, 2010 4:01 am
Forum: Valveless pulsejet forum
Topic: first start of my newly built lockwood-hiller pulsejet
Replies: 6
Views: 2560

Re: first start of my newly built lockwood-hiller pulsejet

Ah, Mr Bernoulli, he's killed a lot of valveless pulsejet engines in his day and I've got plenty of flat tailpipes of my own.
by Bruce Simpson
Thu Jul 08, 2010 3:55 am
Forum: Valved pulsejet forum
Topic: problems starting a lpg/propane pj
Replies: 22
Views: 5879

Re: problems starting a lpg/propane pj

Can you take some video and post it to YouTube so we can see what it's doing?
by Bruce Simpson
Tue Jul 06, 2010 10:50 pm
Forum: Valved pulsejet forum
Topic: problems starting a lpg/propane pj
Replies: 22
Views: 5879

Re: problems starting a lpg/propane pj

Firstly, be aware that unless it specifically states otherwise, there's a fair chance that the camping gas will contain high levels of butane which sucks as a pulsejet fuel. It's boiling temperature is too high so it produces very little vapor pressure. You really need good propane. Secondly, you're...
by Bruce Simpson
Sat Jul 03, 2010 10:49 pm
Forum: Buy and Sell
Topic: Intrested
Replies: 1
Views: 1987

Re: Intrested

Gas-welded stainless?

Are you talking oxy-acetylene?

How are you purging the back of the welds?
by Bruce Simpson
Sat Jul 03, 2010 8:55 am
Forum: Valveless pulsejet forum
Topic: first start of my newly built lockwood-hiller pulsejet
Replies: 6
Views: 2560

Re: first start of my newly built lockwood-hiller pulsejet

Is there a Lockwood style engine out there that will produce 100 lbs of thrust? Is there a way to figure out what size combustion chamber I will need and then use the ratios to build the engine? Thanks for your time, Keith McConnell The lockwoods I used on my twin-pulsejet dragster produced 160lbs ...
by Bruce Simpson
Thu Jul 01, 2010 11:07 pm
Forum: Valveless pulsejet forum
Topic: first start of my newly built lockwood-hiller pulsejet
Replies: 6
Views: 2560

Re: first start of my newly built lockwood-hiller pulsejet

metiz wrote:no you can't just scale up a pj by increasing all the dims x1.5. Acoustics don't work like that, unfortunately
It will run, but it won't be optimal.
by Bruce Simpson
Mon Jun 28, 2010 11:31 pm
Forum: Valved pulsejet forum
Topic: Bruce Simpson
Replies: 32
Views: 24318

Re: Bruce Simpson

Hello Bruce Do you have a raw version of that video lying around somewhere? I realy hate that slapped on turbine sound No, that was taken from the final-edit of the TV show on which it appeared. Idiot producers and directors seem to think that all jet engines should make a turbine sound (sigh!). Wh...
by Bruce Simpson
Sun Jun 27, 2010 11:54 pm
Forum: Valved pulsejet forum
Topic: Bruce Simpson
Replies: 32
Views: 24318

Re: Bruce Simpson

I have built a lot of projects over the past 40 years and several were gocarts. A 100 lb trust engine on a gocart is very slow take off. It will get you up to about 100 mph top speed but that will take a whole mile of flat level road with no head wind or curves and several minutes to get up the spe...
by Bruce Simpson
Wed Jun 23, 2010 10:55 pm
Forum: Valved pulsejet forum
Topic: NEW GERMAN 90er Pulse Jet
Replies: 25
Views: 12772

Re: NEW GERMAN 90er Pulse Jet

I think it's because not everybody has a spare grand lying around to buy a half decent TIG welder TIG welders are now a *lot* cheaper than they used to be. You can get started with a brand-new system for as little as US$350 thanks to modern inverter technology and the influence of cheap Chinese lab...