Search found 39 matches

by fterh
Mon Jul 06, 2009 8:00 am
Forum: Valveless pulsejet forum
Topic: Few Quick Questions...
Replies: 79
Views: 19987

Re: Few Quick Questions...

Any advice how to get the stainless steel strainer off the mold? :?

http://www.fabcode.org/2009/07/05/how-c ... so-flimsy/
by fterh
Wed Jul 01, 2009 10:10 am
Forum: Valveless pulsejet forum
Topic: Few Quick Questions...
Replies: 79
Views: 19987

Re: Few Quick Questions...

http://www.fabcode.org/2009/07/01/remarkable-progress-on-my-homemade-ramjet/ My progress so far, just wondering if the off-course cut is a severe mistake that will interfere with smooth operation of the ramjet. And if butane is okay. I plan to use a hair dryer to blow air in and spray the butane in ...
by fterh
Wed Apr 22, 2009 12:29 pm
Forum: Valveless pulsejet forum
Topic: Few Quick Questions...
Replies: 79
Views: 19987

Re: Few Quick Questions...

That's an axial fan - a fan that blows air parallel to its shaft axis. "Centrifugal fan" is an engineering term for what most people call a "blower", but also covers an "impeller" (like the little spinner inside a leaf blower). Either one can be made in a high volume and/or high speed form, but of ...
by fterh
Wed Apr 22, 2009 12:04 pm
Forum: Valveless pulsejet forum
Topic: Few Quick Questions...
Replies: 79
Views: 19987

Re: Few Quick Questions...

Any fan that provides enough flow at a reasonably high speed should work. Axial fans will have a lot of torque (twist) to the output flow, so on these you should provide a reasonably long "flow straightener", even if just crudely put together from a bundle of tubing scraps. A centrifugal fan probab...
by fterh
Wed Apr 22, 2009 10:42 am
Forum: Valveless pulsejet forum
Topic: Few Quick Questions...
Replies: 79
Views: 19987

Re: Few Quick Questions...

Think I'll skip that. I made this for fun and I am not prepared *now* to spend unnecessary money on this construction :P

And I don't have a vacuum cleaner that blows or a leafblower.. will a really really powerful PC 120mm fan hooked up to a 12V battery work? Hmm.
by fterh
Mon Apr 20, 2009 12:16 pm
Forum: Valveless pulsejet forum
Topic: Few Quick Questions...
Replies: 79
Views: 19987

Re: Few Quick Questions...

I like the diffuser except for the rolled region at the front. Remove that part completely, and hammer the edge outward to form a SMALL flared intake -- just a few mm long x a few mm outward from the basic curve of the "cone". True, a flared inlet will take away a little of the overall diffuser rat...
by fterh
Mon Apr 20, 2009 11:38 am
Forum: Valveless pulsejet forum
Topic: Few Quick Questions...
Replies: 79
Views: 19987

Re: Few Quick Questions...

Okay this is my flameholder and my diffuser. Any comments howsoever? Like, anyway my diffuser/flameholder can be improved, should the flameholder go [ or ] (intake from left, exhaust to the right).. etc.. :D http://i41.tinypic.com/b7ce12.jpg http://i43.tinypic.com/oadyfl.jpg http://i41.tinypic.com/9...
by fterh
Fri Apr 17, 2009 12:59 pm
Forum: Valveless pulsejet forum
Topic: Few Quick Questions...
Replies: 79
Views: 19987

Re: Few Quick Questions...

I just thought of something omg.

After JB welding the diffuser to the flameholder and combustion end of the ramjet there is simply no way to take it apart and make adjustments? So if I did something wrong I gotta re do from scratch? :?
by fterh
Fri Apr 17, 2009 7:20 am
Forum: Valveless pulsejet forum
Topic: Few Quick Questions...
Replies: 79
Views: 19987

Re: Few Quick Questions...

Don't worry about following the exact specs -- it was all guesswork to begin with, anyway. Roughness and/or bumpiness inside the diffuser could be a problem, but I wouldn't be bothered by it until you've tried it. If the diffuser action is poor, you'll probably see some rough combustion, or maybe c...
by fterh
Thu Apr 16, 2009 11:39 am
Forum: Valveless pulsejet forum
Topic: Few Quick Questions...
Replies: 79
Views: 19987

Re: Few Quick Questions...

I'm almost done with the diffuser, but the thing is that the cut is not perfectly straight. It goes up a little then down a bit, so it's uneven and bumpy. And also I did not follow the specifications on the maggie muggs design page, does this mean it won't work? :shock: :(
by fterh
Fri Mar 20, 2009 2:39 am
Forum: Valveless pulsejet forum
Topic: Few Quick Questions...
Replies: 79
Views: 19987

Re: Few Quick Questions...

Okay this is beautiful. After the first crooked cut, I start again on another fresh area of steel.

Now I have like 3inches of straight cut. It's beautiful. :D
by fterh
Wed Mar 18, 2009 8:11 am
Forum: Valveless pulsejet forum
Topic: Few Quick Questions...
Replies: 79
Views: 19987

Re: Few Quick Questions...

Okay I cut 2 inches in an hour last night but it's sort of crooked.

Oh god it's damn hard to cut it straight though I have a line drawn there to guide the cut. I think 1/2 inch will be wasted, the remaining 1.5inches can be fixed by using JB weld I hope :S
by fterh
Tue Mar 17, 2009 12:47 pm
Forum: Valveless pulsejet forum
Topic: Few Quick Questions...
Replies: 79
Views: 19987

Re: Few Quick Questions...

Exactly. You just "inch your way around" until you've completed the cut. The last little bit is difficult, because of the instability of the almost-cut sections that are no longer fully locked together. L Cottrill Okay I bought a saw that can cut metal (according to the storekeeper) and some diamon...
by fterh
Tue Mar 17, 2009 4:20 am
Forum: Valveless pulsejet forum
Topic: Few Quick Questions...
Replies: 79
Views: 19987

Re: Few Quick Questions...

Well, I agree my description wasn't too clear. What I'm saying is, you DON'T cut clear ACROSS the curve (like sawing through heavy pipe); you only cut down the NEAR side, until you get all the way round. Each forward stroke cuts a bit, then after you cut down a little, you rotate the piece away a l...
by fterh
Mon Mar 16, 2009 2:13 pm
Forum: Valveless pulsejet forum
Topic: Few Quick Questions...
Replies: 79
Views: 19987

Re: Few Quick Questions...

Make sure you use a NEW hacksaw blade and take it slow. Once you get the cut started, cut all the way AROUND the piece, NOT across it. It might help to notch the line before you start the cut with the sharp corner of a small half-round file. Your hacksaw cuts on the FORWARD stroke (if you have the ...