Search found 4142 matches

by larry cottrill
Fri Nov 12, 2010 3:13 am
Forum: Valveless pulsejet forum
Topic: Big Linear FWE for a Paying Client
Replies: 60
Views: 52366

Success and Failure

This design ran well, but had to be written off as a technical failure for structural reasons. The problem is those thick plate engine mount blades. I assumed that their heat sinking capability would keep the chamber trued up. Eric Beck warned me of problems ahead (he could see this coming clearly);...
by larry cottrill
Thu Nov 11, 2010 3:27 am
Forum: Off topic forum
Topic: FINALLY, New Deck Is All Finished
Replies: 1
Views: 3477

FINALLY, New Deck Is All Finished

Just thought you might like to see the new front deck I mentioned long ago, now completely finished. My son Jonathan built the whole thing, working entirely alone except for my help with the concrete work and the very heavy lower framing. This took him about a year to build, since he could work on i...
by larry cottrill
Thu Aug 05, 2010 2:56 am
Forum: Valveless pulsejet forum
Topic: new member
Replies: 5
Views: 6316

Re: new member

Using a larger pipe diameter means you'll probably need to lengthen it some. Make a sliding sleeve that you can slip over the tail end. It does not have to fit snugly, but you do have to keep it from creeping (lock it on with a hose clamp). Start with an extra 1/2 inch (13mm) and gradually work it o...
by larry cottrill
Tue Aug 03, 2010 5:25 pm
Forum: Valveless pulsejet forum
Topic: new member
Replies: 5
Views: 6316

Re: new member

I agree -- nice build, from the photo. Since this is your first try, I would ask you this: Are you starting with the LEAST amount of air that will make it buzz? One of the most common mistakes for beginners is thinking they need to provide LOTS of air. This is wrong -- it gives you a starting setup ...
by larry cottrill
Wed Jul 28, 2010 6:32 pm
Forum: Valveless pulsejet forum
Topic: Rainy Day Project: Lady Anne Rev 09
Replies: 12
Views: 11677

Prototype Drawing

Still haven't set aside an evening for a test run, but over the last few days I've thrown together a small-scale dimension drawing and a full-scale section right at the inside end of the intake tube. I have tried to clearly show how the sides of the intake shell forward of the intake are hammered in...
by larry cottrill
Thu Jul 22, 2010 6:46 pm
Forum: Off topic forum
Topic: Scratch Building a U-Control Classic
Replies: 1
Views: 3153

Scratch Building a U-Control Classic

Last year, my wife was talked into getting me the plan set for the classic 1937 original U-control kit model, the famed A-J Fireball, designed by Jim Walker (the patent holder for the U-control flight system). This year, I decided to try to build it. I am not building it to be "authentic", mainly be...
by larry cottrill
Mon Jul 19, 2010 11:10 pm
Forum: Valveless pulsejet forum
Topic: Rainy Day Project: Lady Anne Rev 09
Replies: 12
Views: 11677

Re: Rainy Day Project: Lady Anne Rev 09

Johanssen - No, that's not the problem. I never tried to use the little camera you kindly provided for video, only still shots. This is because we already had a non-digital Sony camcorder that I was used to using. My problem always was not having a way on my own to run off the tape onto a digital fi...
by larry cottrill
Sat Jul 17, 2010 11:32 pm
Forum: Valveless pulsejet forum
Topic: Rainy Day Project: Lady Anne Rev 09
Replies: 12
Views: 11677

Re: Rainy Day Project: Lady Anne Rev 09

I haven't been able to get video capture to work for a long time now. I could throw together some footage of the big heater running, but it wouldn't look like much -- just daylight stuff where you can't really see anything that impressive happening. If this little Lady Anne is a good runner, I'll ge...
by larry cottrill
Sat Jul 17, 2010 7:22 pm
Forum: Valveless pulsejet forum
Topic: Rainy Day Project: Lady Anne Rev 09
Replies: 12
Views: 11677

Mounted Up Ready To Go

Well, I've really been dawdling on this, due to "other commitments". Ha. Anyway, I finally decided that I'd try it with a Grim style "trilobite" injector, which I fabricated easily by modifying the business end of an existing fuel pipe. My idea is that MAYBE this will start without auxiliary air. We...
by larry cottrill
Wed Jul 07, 2010 5:52 pm
Forum: Valveless pulsejet forum
Topic: Rainy Day Project: Lady Anne Rev 09
Replies: 12
Views: 11677

Re: Rainy Day Project: Lady Anne Rev 09

Got the main shell fully welded up a few minutes ago. Now all that's left is making the starting air and fuel pipes.

L Cottrill
by larry cottrill
Wed Jul 07, 2010 3:24 am
Forum: Valveless pulsejet forum
Topic: Rainy Day Project: Lady Anne Rev 09
Replies: 12
Views: 11677

Re: Rainy Day Project: Lady Anne Rev 09

That's some good work, Larry! Thank you, sir! Now if I can only finish on thing I've started ;-) How big is the intake hole and where is it positioned on the cone? The smart alec answer is "What you see is what you get -- the hole is clearly shown in the third photo." That's absurd, of course. Here...
by larry cottrill
Tue Jul 06, 2010 6:00 pm
Forum: Valveless pulsejet forum
Topic: Rainy Day Project: Lady Anne Rev 09
Replies: 12
Views: 11677

Rainy Day Project: Lady Anne Rev 09

Here's one I've been wanting to try for quite a while, but just never found the time. Recently, though, I realized that one way to do this was by cannibalizing the main tube from my old, unsuccessful, Lady Anne Boleyn Rev 03 engine prototype (since I have been long convinced that it will NEVER run)....
by larry cottrill
Thu Jun 03, 2010 4:25 pm
Forum: Valveless pulsejet forum
Topic: Senior Project FWEVIII Rev 8
Replies: 16
Views: 17111

Re: Senior Project FWEVIII Rev 8

corkey - CONGRATULATIONS! Looks like a nice build and nice run for a nice loud lady. My experience with regulators has always been good, because I always get nice big ones with plenty of flow capacity. Yes, your next homework assignment is definitely to do whatever it takes to get a thrust figure. L...
by larry cottrill
Tue May 04, 2010 2:49 am
Forum: Valveless pulsejet forum
Topic: Thrust augmenters
Replies: 2
Views: 4350

Re: Thrust augmenters

Nick -

Go back to the Board Index, click on Frequently Asked Questions at the top, then click on the article by Bruno:
How to Calculate the Size of a Thrust Augmenter

That should give you what you need.

L Cottrill
by larry cottrill
Fri Apr 30, 2010 8:46 pm
Forum: Valveless pulsejet forum
Topic: Big Linear FWE for a Paying Client
Replies: 60
Views: 52366

Client Acceptance

I'm not around much these days, but just wanted to drop by and say "neeto"! That's a mighty big one for a guy that likes little ones so much. Mike, let me tell you, there are some surprises when you build your first big engine. I started grass fires about four times out behind my test stand. I burn...