Search found 128 matches

by Dave_G
Wed Dec 27, 2006 1:45 am
Forum: Tools and Construction
Topic: Stainless, superalloys, or other??
Replies: 16
Views: 8430

Re: Stainless, superalloys, or other??

...Plus as the engine heats up, the ceramic will expand faster than the steel, putting pressure against the shell and eliminating any kind of structural problems. I thought steels had a far higher coefficient of thermal expansion than ceramics, by several orders of magnitude (particularly Al2O3)? M...
by Dave_G
Wed Dec 27, 2006 1:31 am
Forum: Tools and Construction
Topic: Stainless, superalloys, or other??
Replies: 16
Views: 8430

Re: Stainless...Superalloys...

Are you SURE aboout Tungsten Carbide heat shield tiles covering the space shuttle?!? It's incredibly heavy (S.G. = 15.63). That's a lot of mass on a space shuttle. This doesn't seem quite right for aerospace vehicle, where every lb counts...If it's true I'll be shakin' my head in amazment... Have yo...
by Dave_G
Wed Dec 27, 2006 1:11 am
Forum: Valveless pulsejet forum
Topic: 1st pulse jet
Replies: 16
Views: 7475

Re: 1st Pulse-jet

Here's what mine looks like: As I said I replaced the cart's original perf-metal deck with a 4-inch C-channel and welded half-round's on the underside to help hold various engines in place. When testing, I can change out an engine in a few minutes this way. I use those vise-grip chain clamps (also f...
by Dave_G
Wed Dec 27, 2006 12:10 am
Forum: Valveless pulsejet forum
Topic: Mike' Mini kenny build bits
Replies: 27
Views: 13297

Re: Mike' Mini kenny build bits

Lookin' good, Mike! I can't wait to see a video of it running, and see how the operating frequency compares to mine. This version looks like the exhaust has been elongated slightly, and seems to have a slight restriction at the exhaust throat? Also, from your photos, the bustle looks a little bigger...
by Dave_G
Tue Dec 26, 2006 11:52 pm
Forum: Tools and Construction
Topic: solarflux
Replies: 3
Views: 2532

Re:Solarflux

Also note: Let it stand for several minutes AFTER mixing and BEFORE application. The manufacturer says that there is a chemical reaction that occurs between the methanol and the flux, and this waiting period is necessary to give the reaction time to occur. On really hot days I cover it during this w...
by Dave_G
Sat Dec 23, 2006 3:28 am
Forum: Valveless pulsejet forum
Topic: 1st pulse jet
Replies: 16
Views: 7475

Re: 1st Pulse-jet

I dont even know where to begin to measure the thrust. New to jets but great welding and fabrication skills and having a mandrel bender makes things pretty easy going. You can make a very simple thrust stand from one of those cheap (Harborfreight.com -- "steel mesh deck wagon" ITEM 38137-3VGA) four...
by Dave_G
Sat Dec 23, 2006 3:04 am
Forum: Valveless pulsejet forum
Topic: Jims Little 3 Lb Thermojet
Replies: 297
Views: 126212

Re: Jim's little 3-lb. thermojet

My shop vac died the last week..... I was sitting on the couch dieing with a way to fire the beast up!!...Jim The original Thermojets would start without any air injection at all. You just light one of the two injectors and slowly turn up the propane. Those injectors were different -- they did not ...
by Dave_G
Fri Dec 22, 2006 6:45 pm
Forum: Valveless pulsejet forum
Topic: 1st pulse jet
Replies: 16
Views: 7475

Re: 1st Pulse-jet

It already runs great with just 1 tank. And its not galvanized, its aluminized steel. I know all about the toxic fumes of galvanized. I know all about welding, I can stick, tig, mig, flux core, etc.... Very good. In the photos, some tubing looked aluminized, and some looked galvanized. Sorry for my...
by Dave_G
Fri Dec 22, 2006 6:06 am
Forum: Valveless pulsejet forum
Topic: 1st pulse jet
Replies: 16
Views: 7475

1st Pulse-jet

One last bit of (unsolicited) advice and then I'll leave you alone... It looks like you're using standard electrogalvanized muffler tube for your motor. I'm sure you're probably aware that TIG welding Zinc-plated metals is bad for your health. I etch the Zinc off before welding with an acid dip. Som...
by Dave_G
Fri Dec 22, 2006 5:41 am
Forum: Valveless pulsejet forum
Topic: 1st pulse jet
Replies: 16
Views: 7475

!st Pulse-jet

...Was looking at your pictures again...just a bit of advice, feel free to ignore it or take it with a grain of salt...But when you get that engine really going, so that it's glowing orange, you may have trouble with the heat affecting (softening) your black neoprene fuel hose. It will help to dista...
by Dave_G
Fri Dec 22, 2006 5:16 am
Forum: Valveless pulsejet forum
Topic: 1st pulse jet
Replies: 16
Views: 7475

1st Pulse-jet

I think your engine looks great. It should run just fine, but you may find it helpful to to use two BBQ tanks or a forklift tank to fuel a motor that big. I like the way you joined the straight sections with flares -- very quick to build that way and no cone rolling required. Do you own a muffler sh...
by Dave_G
Thu Dec 21, 2006 5:26 pm
Forum: Valveless pulsejet forum
Topic: as promissed ,pictures
Replies: 10
Views: 4617

pictures

Jerry, I noticed from your posted photos that it appeared that, as of the time the photos were taken, the only valveless pulsejet engine that had been run was your Hiller-Lockwood with the attached Inlet thrust augmentor. When you ran it, did you collect any thrust data, and perhaps the correspondin...
by Dave_G
Tue Dec 19, 2006 5:44 am
Forum: Valveless pulsejet forum
Topic: as promissed ,pictures
Replies: 10
Views: 4617

Re: as promissed ,pictures

jerry marra wrote:...Hiller/Lockwood-Thermojet- Free piston – Glueharef pressure jet - custom design Escopette ...
Nice pictures, thanks!

I didn't see the free-piston engine or the Gluhareff...do you perhaps have more pictures?

You seem to have a ready supply of the stainless sanitary flange fittings -- nice!
by Dave_G
Mon Dec 18, 2006 5:58 am
Forum: Tools and Construction
Topic: Help again... welding
Replies: 18
Views: 11058

re: Help again... welding

Cheat: Just an FYI...That U-bend I made in the photo shown above is the same wall thickness as the tubing shown in your second photo; about 0.065". I made that weld at 75 amps. Anything below 50 and you'll risk burning through, because you'll have to go too slow. I admit that 75 is a little high, bu...
by Dave_G
Mon Dec 18, 2006 3:12 am
Forum: Tools and Construction
Topic: Help again... welding
Replies: 18
Views: 11058

Re: Help again... welding

perhaps stainless just welds ugly... I really don't know. 'Cheat' : Stainless welds beautifully...just takes a little practice -- See attached photo of 180 degree U-bend made from two 90 degree sections of 304SS. It was TIG-welded without filler. Lots of people can give you dozens of tips, but ther...