Search found 22 matches

by SR71Fan
Tue Dec 01, 2009 2:11 am
Forum: Valved pulsejet forum
Topic: Rotary Valve Pulse-Jets
Replies: 43
Views: 18236

Re: Rotary Valve Pulse-Jets

Hello All: It's interesting to see that someone [Mark] has found what appears to be a rotary valve proposal for a pulse-jet. Too bad the text is unreadable. I didn't think that I would have been the first person to suggest this type of valve. I have been working on the software architecture for the ...
by SR71Fan
Mon Nov 02, 2009 3:40 pm
Forum: Valved pulsejet forum
Topic: Rotary Valve Pulse-Jets
Replies: 43
Views: 18236

Re: Rotary Valve Pulse-Jets

Mark: I'm still in the "visionary" stage, so nothing is built to take photos of. But simply imagine a round butterfly valve on a car throttle body, except the butterfly can rotate through 360 degrees instead of having a "stop" when closed. The butterfly plate would also be thicker and heavier, to wi...
by SR71Fan
Sat Oct 31, 2009 3:19 pm
Forum: Valved pulsejet forum
Topic: Rotary Valve Pulse-Jets
Replies: 43
Views: 18236

Re: Rotary Valve Pulse-Jets

Hello All: This is just an update on my work on the rotary valve pulse-jet. I am focusing my attention on the design of the engine control unit (ECU). Since I own a product evaluation kit for one of Freescale Semiconductor's HC08 family parts, that is my choice for the microcontroller. The specific ...
by SR71Fan
Fri Oct 30, 2009 2:19 pm
Forum: Valved pulsejet forum
Topic: Combustion chamber area compared to whole engine area ?
Replies: 3
Views: 1478

Re: Combustion chamber area compared to whole engine area ?

Your description is sort of confusing; first you talk only in ratios, then you talk only in volumes, no ratios. Is this engine some sort of secret design? In any case, here is my opinion: a) consider the cone to be part of the combustion chamber. In this case, Pulso 1's CC of 56% is much larger than...
by SR71Fan
Tue Oct 27, 2009 8:59 pm
Forum: Valved pulsejet forum
Topic: Pulse-Jet Operating Frequency Variations
Replies: 13
Views: 5190

Re: Pulse-Jet Operating Frequency Variations

Tufty: It's not merely "guesswork"... it's **educated** guesswork. There are many things we can infer about the operation of a pulse-jet that are based on fundamental physics. If we can set those issues to rest, we can then focus on what we don't know. I think Eric will agree that the problem with "...
by SR71Fan
Tue Oct 27, 2009 6:02 pm
Forum: Valved pulsejet forum
Topic: Pulse-Jet Operating Frequency Variations
Replies: 13
Views: 5190

Re: Pulse-Jet Operating Frequency Variations

Hello Eric: Here is how I approached the issue of short-term frequency variations Parameters affecting pulse-jet operating frequency --------------------------------------------------- Assume: Fpls = a* / (4 * L) a* = speed of sound inside the pulse-jet (approx. 2100 ft/sec) L = total engine length ...
by SR71Fan
Tue Oct 27, 2009 1:01 am
Forum: Valved pulsejet forum
Topic: Rotary Valve Pulse-Jets
Replies: 43
Views: 18236

Re: Rotary Valve Pulse-Jets

Note to ace_fedde: It's always fun when you can see the light in someone's mind suddenly light up. You probably noted in my post of a day ago that ECU-controlled spark ignition is one of the ECU outputs. And I had considered using spark ignition on every pulse. But there are problems with that appro...
by SR71Fan
Mon Oct 26, 2009 1:05 am
Forum: Valved pulsejet forum
Topic: Pulse-Jet Operating Frequency Variations
Replies: 13
Views: 5190

Re: Pulse-Jet Operating Frequency Variations

Hello Eric: This is regarding your reply to Pulse-Jet Operating Frequency Variations that is dated Sun Oct 25, 2009 12:03 am Thanks for taking the time to reply on this topic. However, it seem that I am miscommunicating or something, because everyone seems to be answering questions that I am not ask...
by SR71Fan
Sun Oct 25, 2009 6:52 pm
Forum: Valved pulsejet forum
Topic: Rotary Valve Pulse-Jets
Replies: 43
Views: 18236

Re: Rotary Valve Pulse-Jets

Hello All: The forum discussion on the Rotary Valve Pulse-Jet has been very informative for me, and I want to thank all the participants for their input. One of my goals for introducing the topic of a rotary valve pulse-jet was to demonstrate the many benefits of this particular valving method, and ...
by SR71Fan
Sun Oct 25, 2009 5:09 am
Forum: Valved pulsejet forum
Topic: Rotary Valve Pulse-Jets
Replies: 43
Views: 18236

Re: Rotary Valve Pulse-Jets

Note to Rocket Man: The attempt to convert a Dynajet from a reed valve to a rotary valve probably failed because the pulse rate with a reed valve will be different than the pulse rate with a rotary valve. The inlet flow restriction, and probably the flow areas will be different, and they will shift ...
by SR71Fan
Sat Oct 24, 2009 7:48 pm
Forum: Valved pulsejet forum
Topic: Pulse-Jet Operating Frequency Variations
Replies: 13
Views: 5190

Re: Pulse-Jet Operating Frequency Variations

Eric: The important parameter is the instantaneous (pulse-by-pulse) variation in the pulse period (1/frequency). If it is actually less that 5% in the short term, then that is acceptable. For the reason I am asking the question, refer to "Rotary Valve Pulse Jet Engine" in the "Valved Pulse Jet" foru...
by SR71Fan
Sat Oct 24, 2009 7:42 pm
Forum: Valved pulsejet forum
Topic: Rotary Valve Pulse-Jets
Replies: 43
Views: 18236

Re: Rotary Valve Pulse-Jets

Could you find a web link to the paper? Or scan it and upload it? If they had no success with the rotary valve, I need to find out why. Of course, if this is true, then my engine concept is also a failure. But with the information I have so far, there is not explanation of **why** the rotary valve f...
by SR71Fan
Sat Oct 24, 2009 1:51 am
Forum: Valved pulsejet forum
Topic: Pulse-Jet Operating Frequency Variations
Replies: 13
Views: 5190

Re: Pulse-Jet Operating Frequency Variations

Rocketman:

In your example, the pulse rate was measured as 220 Hz.
This is an average of 4.545 milliseconds between pulses.

What I am trying to find out is exact time between successive
pulses on a pulse by pulse basis. How much do any of the pulses
change from the 4.545 millisecond average?

SR71
by SR71Fan
Sat Oct 24, 2009 12:24 am
Forum: Valved pulsejet forum
Topic: How to Design Build and Test Pulse Jet Engine.
Replies: 15
Views: 11604

Re: How to Design Build and Test Pulse Jet Engine.

Hello gone2fly: If you care to look at the "Rotary Valve Pulse-jets" topic, you will see my sort of "outside the box" concept for a high performance pulse-jet, and if my bubble is going to be burst, it may as well be from someone who has a lot of experience building pulse-jets. You also may have som...
by SR71Fan
Sat Oct 24, 2009 12:03 am
Forum: Valved pulsejet forum
Topic: Rotary Valve Pulse-Jets
Replies: 43
Views: 18236

Re: Rotary Valve Pulse-Jets

I agree that discontinuous (or pulsed) fuel injection is the way to go,
for several reasons. However, I would recommend a fuel pressure
much higher than 3 bar (42 psi in the U.S.). I was actually thinking
of about 7 bar in order to achieve better atomization of the fuel spray.

SR71