"Thunderchine" 55 lb thrust pulsejet plans

[ganuganu]

hello sir,i saw the video of your engine that was really awesome and excellent..really liked it..i have made an M40 engine(metiz plans)..but i used an 5kg LPG to start but it didnt start just gave large flames and howling sounds..and i thought of using 15kg LPG cylinder is it enough for my engine to start..here is the video..

http://www.youtube.com/watch?v=3gpQ1kanqQQ

[bobobob]

i cant seem to be able to get the plans. i see the links but they are unclickable. can you email them to me or something? any help would be appreciated

[daab]

Could tell us how to get the plan?

Thanks

daab

[bryce.march]

I seem to be having the same issue - everything is unclickable and I can't see the plans.

[brownms]

Do plans exist for a 25 lb thrust Thunderchine?

[metiz]

Nope. You can try the M25 though

[brownms]

Hi Metiz...

I have built an M-25, but not run it yet. Within the next few weeks hopefully.

Correct me if I'm wrong, but the idea behind designing a well-running valveless pulsejet is to match the resonant frequencies of the various tubes that make up the unit.
For example the M-25 is 1.036 m long, at a combustion temperature of 954 deg.C gives a resonant frequency of 152 Hz.

Should the inlet tubes be tuned to a harmonic of this fundamental frequency?
For example an inlet tube of length 0.169 m at an air temperature of 25 deg.C gives a resonant frequency of 911 Hz
This 911 Hz is a 6x multiple of 152 Hz.

How many of the various parts of the pulsejet unit need to be 'tuned' to length?

[metiz]

Yes, basically you are right. It's not as simple as a straight pipe though, lots of different temperatures, shapes and sizes. I'm not realy into the math part of these engines. The M25 has been designed with the bare minimum of math required and it's my best engine so far. The intakes can be SLIGHTLY fatter but other than that it's just about around the theoretical limit.

The intakes are quarter wave resonators.

[brownms]

If the intake is a 1/4 wave resonator, this suggests a closed-end tube.
Does that mean that the length of the intake is calculated as the length of the intake tube plus the distance to the closed end of the combustion chamber?

[brownms]

I am currently building a Thunderchine.
I cut the inlet holes (in the combustion chamber cone) with an angle of 75 degees between the two.
This looks a lot closer than the plans suggest. Is this going to cause any problems?

Mike

[metiz]

Dit you measure from the centre of the holes? There are cutouts available if you're unsure. Any pictures?

[brownms]

I designed my own Thunderchine model with Solidworks based on the Thunderchine plans. I printed a flat pattern cone (the part that the inlets weld to) to use as a temple for the sheetmetal. I fabricated and welded the cone without the inlet holes and then measured 75 degrees between hole centers. I then took the inlet tubes and placed them on the cone (75 degrees apart) and traced around them. The two shapes that were marked onto the cone became the shapes to cut out of the cone to fit the inlet tubes.

If it is OK to have 75 degrees between inlets then I'll run with it, if not ,I'll make another cone. See attached for photo.

TC-55 Inlet Cone

[metiz]

If I remeber correctly the intake separation was 120 degrees. This engine is a REALY tight build, very low tollerances. I'd say use the available templates. If you want to use your own stuff, make the layouts such that you don't have to trace anything (i.e., make your solidworks patterns so that the holes are already on the paper) also don't forget to take into account material thickness. It's the small details that will determine if this engine runs or not. It's a good idea to replace your choke.

[brownms]

Metiz...

As-built dimensions.

Mike

[brownms]

Metiz...

As -built intake dimensions.


Mike