Questions/comments about my Pulsejet Design.

[RBMK]

Hi@all

I may want to built a little bit bigger Valved Pulsejet like the 100LB Version of Bruce Simpson.

I have tried to plan to make the valvehead-design more easier to mount on the combustion chamber (watch the Attachment) (comments please).

And now two last questions, first about the Pulse-jet calculator , has anyone used this calculator to make a good working design ?

And the second question ist , where is it better to inject the fuel ? In Front of the Valve's or behind them ( direct in the Combustion chamber ) ?

Regards

[Jonny69]

I don't completely understand your drawing. Is the valve plate mounted at 90 degrees to the combustion chamber, facing to one side? That would not be good.

Propane injection is best directly behind the valves.

[Najm]

No ,he is showing the valve and engine seperately, a plate is welded to the intake of the pulsejet and the valves are on another plate , then both plates are joined together by nuts and bolts.

[_Rahul_]

Is that a SCHEMAtic diagram or u really have that Long combustion Chamber and smaller exhaust? The calculations must be correct. Also its pretty good to have fuel nozzle, injecting fuel, behined the valves if u are using a gaseous fuel or a very very volatile fuel. It gets mixed with air pretty gud and is sucked into the combustion Chamber as a fuel mixture. But if u are planning to use liquid fuel ... inject the fuel right into the combustion chamber!

One question .. Did u used "ready-made" valves or u made them? If U made them .. I will be pretty interested how u made 'em!

[RBMK]

It's Just schematic .

regards

[RBMK]

I have another question about the " V Cage " Valve Design.

It's not easy to explain my question but i try.......

I'm using the Pulsejet Calculator 1.4 , there are different types of Valves.

Just imagine the room of the Combu.chamber ist for example 1000ccm

You are using NO "V-Cage Valves" and now imagine you are using "V Cage" Valves on the same Combu.chamber. The Room of the Combu.chamber is now smaller because this " V-Cage " is taking some Room of the Chamber .... but when the Combu.chamber is smaller... all the calculations??? must be wrong ??? for Example Tailpipe length .... , but how critical is that ?



My last question is , how thick must the Steel-Sheets be @ such a large engine ?

regards Warezkind

Regards RBMK

[Eric]

I have made a few valved engines in the 1 - 300 lb thrust range with the dimensions from my calculator.

The different dimensions are for different valve systems, regular petal valves are very innefficient and need a large combustion chamber to provide the necessary cross sectional area for the valves.


The valve grid, is smaller in diameter because the valves are much better at letting air flow into the engine, and they should not protrude into the engine significantly to affect performance.

The reduction in volume is a function of valve design, and not terribly critical, especially if you use the suggested tuned intake length.

Eric

[Najm]

Is the intake cone? If so then what is its minimum diametre?

[Al Belli]

Hi Najm,

The lengths of the system's parts are more important than the diameters.

According to Tharratt, the thrust of the pulsejet can be calculated by the following formula :

( Total system volume in cubic feet / total system length in feet ) X 316

I have found this formula very useful to evaluate the thrust changes due to varying the combustion chamber diameter.

Al Belli

[RBMK]

Hi !

Now I'm searching some steel sheets to start the work.

But how thick must the steel be of the combu.chamber & tailpipe @ 100 - 150 LB thrust ?

regards !