Search found 11 matches

by dwayne247
Thu May 06, 2010 12:26 pm
Forum: Valveless pulsejet forum
Topic: Building a 3 LB thermojet from plans
Replies: 11
Views: 6237

Re: Building a 3 LB thermojet from plans

they probably will probably?:\ lol Anyway, I have a 1/8" O.D brass tubes for the fuel injectors (although plans require stainless steel), but i was wondering what O.D of tubes i will need to connect them to, and what type of welding do i use to hold them together. I made a diagram of what im talkin...
by dwayne247
Wed May 05, 2010 5:20 pm
Forum: Valveless pulsejet forum
Topic: Building a 3 LB thermojet from plans
Replies: 11
Views: 6237

Re: Building a 3 LB thermojet from plans

i got the tailpipe welded to the cone today.. and i would have got the CC welded on to but.. i realized they were just brazing it instead of gas welding it with steel! now i have to travel nearly 12-14 Kms tomorrow to get to where all the gas welding shops are :\ Im hoping the brazing wont melt when...
by dwayne247
Tue Apr 27, 2010 3:13 am
Forum: Valveless pulsejet forum
Topic: Acoustic length
Replies: 13
Views: 3557

Re: Acoustic length

One of the problems for beginners is that the valveless engine is mechanically so simple, they naturally expect the internal operation to be simple and the design straightforward. But you are dealing with the chaos of chemical explosions and all the variables that this entails. Appearances are dece...
by dwayne247
Tue Apr 27, 2010 3:11 am
Forum: Valveless pulsejet forum
Topic: Acoustic length
Replies: 13
Views: 3557

Re: Acoustic length

Thank you so much Larry and Hinote for actually taking the time to give me an answer. From what i see is that the acoustics aren't everything and they are highly dependable on working conditions which are highly dependable on the shape. Resulting in greatly varying performance as the engine is scale...
by dwayne247
Sun Apr 25, 2010 6:33 pm
Forum: Valveless pulsejet forum
Topic: Acoustic length
Replies: 13
Views: 3557

Re: Acoustic length

thank you Paul and Larry :) the reason this topic came to my mind is because of a doubt i have about scaling PJ plans. Larry, taking your FWE PJ, when its running at certain frequency , it is resonating at a certain wavelength. The engine now is running efficiently, delivering good thrust. Now if i ...
by dwayne247
Fri Apr 23, 2010 4:21 am
Forum: Valveless pulsejet forum
Topic: Acoustic length
Replies: 13
Views: 3557

Acoustic length

Usually in pulse jets, the chamber isn't of equal diameter through out. Its broader at the CC and narrow at the tail pipe. Does this effect the acoustic length of the engine? or would the acoustic length be the same if the diameter was the same throughout. (in other words do changes in the volume of...
by dwayne247
Wed Apr 21, 2010 12:32 pm
Forum: Valveless pulsejet forum
Topic: Building a 3 LB thermojet from plans
Replies: 11
Views: 6237

Re: Building a 3 LB thermojet from plans

Another thing is, does the combustion chamber and exhaust pipe act as two separate pipes? As in the CC acts as a pipe with a one closed and one open end, whereas the exhaust pipe acts a pipe open at both ends. Or do both together act as ONE pipe closed at only one end?
by dwayne247
Wed Apr 21, 2010 10:43 am
Forum: Valveless pulsejet forum
Topic: Building a 3 LB thermojet from plans
Replies: 11
Views: 6237

Re: Building a 3 LB thermojet from plans

yeh ok i will check that out. :) This is a little off but, i've been reading and searching alot about the "acoustics" of a pulse jet engine but i just cant understand what is meant by "properly exploiting the acoustics of a pulse jet to increase efficiency/thrust". And how do you know if your engine...
by dwayne247
Sun Apr 18, 2010 7:07 am
Forum: Valveless pulsejet forum
Topic: Building a 3 LB thermojet from plans
Replies: 11
Views: 6237

Re: Building a 3 LB thermojet from plans

i got the funnel thing from the 3" to the 1.5" pipe done. i got it cut from a hollow oval shape steel ball. Im gonna over to a friends place and drill the intake holes into it today evening. i hope it goes well. :|
by dwayne247
Thu Apr 15, 2010 5:59 pm
Forum: Valveless pulsejet forum
Topic: Building a 3 LB thermojet from plans
Replies: 11
Views: 6237

Re: Building a 3 LB thermojet from plans

oh ok thanks Eric :)
and what about a .6" with a good flare?
by dwayne247
Thu Apr 15, 2010 4:54 pm
Forum: Valveless pulsejet forum
Topic: Building a 3 LB thermojet from plans
Replies: 11
Views: 6237

Building a 3 LB thermojet from plans

Hey everyone :) This is my first post here and the first time im building a valveless jet engine. i got the plans from this forum, i think from a post named "jims little 3LB thermojet". its a valveless thermojet engine that should give about 2-3 LBs of thrust ( as said in the plans ) and it seems go...