Search found 10 matches

by gerre
Sun Sep 20, 2015 1:20 am
Forum: Valved pulsejet forum
Topic: 95 octane vs 98 octane grade gasoline
Replies: 3
Views: 2023

Re: 95 octane vs 98 octane grade gasoline

Thanks for the reply Robert. I was able to make them run with both 95 and 98 octane gasoline, but it was indeed pretty dificult to get the engine started. Anyway, I'm just doing some experiments. I'd like to run the engine on methanol too, but I think I will need to modify my flowjector and perhaps ...
by gerre
Tue Sep 01, 2015 8:13 pm
Forum: Valved pulsejet forum
Topic: 95 octane vs 98 octane grade gasoline
Replies: 3
Views: 2023

95 octane vs 98 octane grade gasoline

Hi all, Well, I have the following thought last days when using my valved PJ: Is there any difference between 95 octane an 98 octane grade gasoline when using it with pulse jets? I know that 98 grade octane is used for engines with a high compression ratio, but pulse jets have a low compression rati...
by gerre
Mon Aug 24, 2015 10:24 pm
Forum: Valved pulsejet forum
Topic: Hobby King Dyna jet
Replies: 18
Views: 10183

Re: Hobby King Dyna jet

The pulse jet worked! :) But I still have a lot of questions regarding the engine parameters. The biggest one is the specific impulse: I found that pulse jets normally have a specific impulse of around 1000-1500s, but the specific impulse for the dynajet/HK pulse jet is only 58s, according to my cal...
by gerre
Fri Aug 21, 2015 11:37 am
Forum: Valved pulsejet forum
Topic: Hobby King Dyna jet
Replies: 18
Views: 10183

Re: Hobby King Dyna jet

I already measured the angle of the blowpipe and I think there's nothing wrong with it (35 degrees). Anyways, I'm going to try running it without the solenoid valve and by putting the fuel tank closer to the metering jet. And you are right, it is silicon tubing. My bad :) Thanks for helping, will ke...
by gerre
Thu Aug 20, 2015 6:34 pm
Forum: Valved pulsejet forum
Topic: Hobby King Dyna jet
Replies: 18
Views: 10183

Re: Hobby King Dyna jet

It's not a fuel pump. It's a solenoid valve, acting as an emergency valve. Anyways, I don't think the solenoid valve is the problem because the engine is drawing fuel from the tank very good. The petal valve is aligned and intact. And I would be surprised if the metering jet is clogged, because of t...
by gerre
Tue Aug 18, 2015 10:32 pm
Forum: Valved pulsejet forum
Topic: Hobby King Dyna jet
Replies: 18
Views: 10183

Re: Hobby King Dyna jet

Hi all, I've had alot of problems trying to start my HK pulse jet ( see the attachment) I get bangs and sometimes it seems very close to getting into resonance, but I'm afraid I'm still doing something wrong. I used 60psi compressed air and 95 octane gasoline as fuel. During the first test yesterday...
by gerre
Wed Aug 12, 2015 6:16 pm
Forum: Valveless pulsejet forum
Topic: Please put your "I am new and need help" question here.
Replies: 376
Views: 1763116

Re: Please put your "I am new and need help" question here.

Thanks for the information! Overwhelming that such a mechanically simple engine can be so thermodynamically complex. And for some reason I'm not able to find the exact thermodynamic cycle. A lot of people say it's working on the Lenoir cycle, other people say it's Humphrey, some people even say Bray...
by gerre
Sat Aug 08, 2015 7:29 pm
Forum: Tools and Construction
Topic: Cooling HK pulse jet
Replies: 2
Views: 1395

Re: Cooling HK pulse jet

Thanks for the reply. I guess I wil do a little bit research about the water cooling :)
Though I still don't know what my mentor meant by "fueling cooling". I guess he was refering to the water cooling.
by gerre
Thu Aug 06, 2015 10:55 pm
Forum: Tools and Construction
Topic: Cooling HK pulse jet
Replies: 2
Views: 1395

Cooling HK pulse jet

Hi all, In the context of my thesis I'd like to bench run my HK pulse jet, but for longer than 10 seconds. Does anybody know any other means of engine cooling, apart from a leaveblower? I read that using methanol as a fuel has a cooling effect on the engine, but you apparently have to do a "methanol...
by gerre
Fri Jul 31, 2015 10:47 pm
Forum: Valveless pulsejet forum
Topic: Please put your "I am new and need help" question here.
Replies: 376
Views: 1763116

Re: Please put your "I am new and need help" question here.

Hey everyone, I'm a student aeronautical engineering and I'm new here on this forum. In the context of my thesis I'm looking for the exact working principle behind pulse jets. I know that the Kadency effect forms the basics for a pulse jet to work, but during my research I also saw other effects lik...