Search found 128 matches

by Dave_G
Mon Jul 16, 2007 2:16 pm
Forum: Valveless pulsejet forum
Topic: My latest Thermojet
Replies: 29
Views: 10512

Re: Electrical vs Thermoacoustic

I disagree that impedance is only drag in this case. Drag would be the "resistance" component. There is also force needed to accelerate the gas mass in the pipe, though in the case of the intake this seems pretty small. That inertial component is the "reactance" part of our total impedance. Like an...
by Dave_G
Thu Jul 12, 2007 3:48 pm
Forum: Valveless pulsejet forum
Topic: My latest Thermojet
Replies: 29
Views: 10512

...The only diversion from plans is that I took Eric's advice to take the inlets flush to the cone. (hopefully for better breathing). My understanding is that this shouldn't alter inlet tuned path length's, we shall see... I'm sure it'll work just fine. The 3-inch (J3-200) engine I have is the same...
by Dave_G
Thu Jul 12, 2007 2:41 am
Forum: Valveless pulsejet forum
Topic: My latest Thermojet
Replies: 29
Views: 10512

Re: My latest Thermojet

Eric's free design... Built it with the hope of being able to start with no to little air supply. Very nice execution! I have a 3-inch clone and a 5-inch Melenric Original that I bought from Bryan Seegers of M-Dot Aerospace, and they both start readily with a lit match, applied to a single inlet no...
by Dave_G
Wed Jul 11, 2007 7:39 pm
Forum: Valveless pulsejet forum
Topic: Lady Anne Boleyn Rev07 Full Size Plan Drawings
Replies: 53
Views: 24070

Re: Lady Anne

My original starting tube setup was just the opposite: The air line surrounded the fuel line, but was cut short while the fuel line went on down the throat. I have felt that the air should undergo a slight dispersion, turbulence, etc. on its way in, to aid in mixing. This seems not to be the case, ...
by Dave_G
Tue Jul 10, 2007 6:17 pm
Forum: Valveless pulsejet forum
Topic: Lady Anne Boleyn Rev07 Full Size Plan Drawings
Replies: 53
Views: 24070

Re: Lady Anne

Here's my finished mild steel prototype and a couple closeups of the front engine mount for static running. Larry, I just caught your rendition (in metal) of the "Lady Anne" on this thread. Very nice work! After looking at your photos, one suggestion immediately comes to mind. You can choose to bel...
by Dave_G
Fri Jun 22, 2007 3:53 pm
Forum: Valveless pulsejet forum
Topic: HPX Goes MASSIVE
Replies: 29
Views: 14987

HPX

Nice work!

Do you have any plans to measure the thrust and fuel consumption?

If so, how will you do it?
by Dave_G
Tue Jun 05, 2007 5:20 pm
Forum: Valveless pulsejet forum
Topic: any body know cool things to do with a pulse jet?
Replies: 43
Views: 15746

Re: Gopher Toaster

berquistj@peoplepc.com wrote: I would like to know more about there fuel system?

Jim
They ran on JP4 or gasoline, or could be run on propane with a nozzle change.
by Dave_G
Thu May 31, 2007 7:08 pm
Forum: Valveless pulsejet forum
Topic: any body know cool things to do with a pulse jet?
Replies: 43
Views: 15746

Re: Things to do w/ a P-J...

The augmentors look like they pretty much conform to Ray Lockwoods original design specs for size, shape and separation. I'd guess that info's already been posted elsewhere on the forum, but if not, see attached.
by Dave_G
Thu May 31, 2007 5:14 pm
Forum: Valveless pulsejet forum
Topic: any body know cool things to do with a pulse jet?
Replies: 43
Views: 15746

Pulsejet Hovercraft

How about a Pulsejet Hovercraft?

I assume this is an SRL project...

Photo Source:
http://www.sscnet.ucla.edu/geog/gessler/topics/

Actually, I think the six retro-curved intakes w/ individual augmenters are interesting...definitely an inspiration from Kentfield.
by Dave_G
Sat Apr 28, 2007 1:26 am
Forum: Pulse detonation engine forum
Topic: PDE not that much better than other engines?.
Replies: 3
Views: 5157

PDE

Check the available literature. You will find aerovalved PDE's (that DO require Oxygen - but are aerovalved nonetheless like a valveless pulsejet) as well as researchers working on air-breathing (ie., not requiring supplemental Oxygen) PDE's. I apologise, but I don't have time at the moment to give ...
by Dave_G
Fri Apr 27, 2007 7:44 pm
Forum: Pulse detonation engine forum
Topic: PDE not that much better than other engines?.
Replies: 3
Views: 5157

PDE not that much better potential than pulsejets?

Kentfield also made a compelling argument for this same position (albeit for different reasons) in his 1998 paper, AIAA 98-3879 (posted elsewhere on this forum), page 6, column 2, paragraph 1. Most PDE's at that time (1998) were not air-breathing, but required their own source of Oxygen. I do know t...
by Dave_G
Wed Apr 18, 2007 7:44 pm
Forum: Valveless pulsejet forum
Topic: hydrogen rocket
Replies: 16
Views: 5976

Re: Hydrogen fuel!

berquistj@peoplepc.com wrote:The water formed within the exhaust would add to the thrust!
Unfortunately, it wouldn't.

The total mass flow is unchanged.
by Dave_G
Wed Dec 27, 2006 6:44 pm
Forum: Tools and Construction
Topic: Stainless, superalloys, or other??
Replies: 16
Views: 8332

Re: Stainless, superalloys, or other??

The operating temperature is usually around 300-400 degrees in the trough which is pouring 2400-2500 F liquid iron. ... the hot faces in a cement/lime kiln will be around 2000-3000 F. The cold faces (and hence the surrounding steel) will be under 600 F, and usually closer to 400 F. This is achieved...
by Dave_G
Wed Dec 27, 2006 5:32 pm
Forum: Valveless pulsejet forum
Topic: 1st pulse jet
Replies: 16
Views: 7346

1st Pulse-jet

Is that a Chatillion brass scale? Mark: Yes. It's a model IN-50. It has dual scales: 0-50 Lb & 0-25 kg. I made a welded stainless wire cage for it so it doesn't drag on the ground and get all scarfed up. The red button 'holds' the maximum reading and it usually does a good job despite the vibration...