50 lbF 'Lady Astor' Not For Beginners

[Mike Everman]

How about an electric blanket?

[Graham C. Williams]

Hi Berry.

When you take all the fuel delivery pipes off try making a Rossco injector or 2 from (say) 10mm pipe. Hand held (with good thick gloves) move them slowly in and out of one of the induction pipes and see if you can get the motor to Hum; you know the sound? Do this with one and then 2 induction pipes blocked (Potatoes should do the job).

Graham.

[Berry]

How about an electric blanket?

Mike i will try to find a way to get it running this year if possible

[Berry]

Mike i already did that so i know the pipes have to be further into the inlets then i can get them now i could move the 3 pipes as you can see in the photo.

Hi Berry.

When you take all the fuel delivery pipes off try making a Rossco injector or 2 from (say) 10mm pipe. Hand held (with good thick gloves) move them slowly in and out of one of the induction pipes and see if you can get the motor to Hum; you know the sound? Do this with one and then 2 induction pipes blocked (Potatoes should do the job).

Graham.

[Berry]

Today i tried again to get the lady astor running.
I had changed the fuelpipes before i tried to get it running ( see url).
The propane bottle and the propane was at a temperature of 27 degrees celsius because i had tracing wrapped around the bottle and alongside the needle valve.
The temperature outside was about 13 degrees celsius.
Things went far better as last week but it is still not running.
The pigtail behind the gasinlets gets frozen when i try to get it running the fuelpipes even freeze till the inlets.
So somehow its caused by the needle valve that has a 4 mm hole internal or by the pipes that fit in the hose they both are 4 mm internal as well.
There is no reducer between the propane bottle and the pulsejet just a 1/2 inch needle valve to regulate the flow (4 mm hole internal) and a ball valve 1/2 inch for an emergency stop.
So if anybody has some new ideas let me know.
http://home.planet.nl/~scher868/suz/pul ... tor06e.htm

[larry cottrill]

Berry -

Just a review of some things you already know ;-)

Once the gas is flowing, it will chill the pipe at (and some distance downstream from) any point where it flows through a small area into a larger area (because this represents a pressure drop). The most obvious spot is the fuel nozzle itself; however, this also applies to any partially opened valve. The point of greatest resistance in a piping circuit will be where the chilling is the greatest. Since you're presumably starting out with a slightly open valve setting, your control valve is probably a serious candidate for where this is happening.

I would think that an ideal setup would be the tank valve feeding a fairly large line that will take full tank pressure, fairly long downstream from the tank valve (to allow heat gain and evaporation), then the quick shutoff valve (normally wide open) and more large pipe to the control valve; the downstream line from the control valve would be only a little larger than the wide-open area of the control valve (to limit expansion) and again fairly long to allow heat pickup and evaporation; then, when the manifold splits off into the engine feeders, the TOTAL area should be as close as possible to the inside cross-section area of the line from the control valve. The nozzles into the intakes will naturally be the smallest total area in the system. Anywhere you have a small line "opening up" into a bigger one is where you'll see frost collecting.

It's hard to safely heat a gas valve. One safe and easy (well, sort of) way I can think of would be to locate your control valve in a large tub near the bottom and fill the tub with the hottest water you can stand. You would reach down into the water to work the valve. You could also provide a small coil of your tubing (downstream from the valve) down in the tub, too, as a re-evaporator. This might do the trick, but doing other necessary tasks in sub-freezing temperatures with wet hands may not be all that appealing. Ha. You could wear wetsuit gloves, I guess (foam neoprene with nylon lining).

There must be some halfway reasonable way to do this - after all, there are lots of places with outdoor propane supplies with pressure-reducing valves (regulators) that seem to keep working year-round.

Darn - it's a shame the fueling issue seems to be such a sticky problem.

L Cottrill

[Berry]

Larry,

thx for your response thats about the same what i was thinking i have to figure out a way to get the flow to the engine a bit better with less narrow points in it and maybe even remove the needle valve and use the valve of the bottle for regulation and only leave the ball valve upthere just to use that in case of emergency.

[GRIM]

I have been following this thread with great interest , by the way Berry that is by far the most beautiful Pulsejet I have ever seen , excellent work

I feel compelled to write because this has been in my mind for a while now , if it is of any help, great.
If not file it under useless information.

Here is s a link , or google “propane vaporizers”
http://www.altenergy.com/2006/Vaporizers.htm

I only had one experience with one of these , the people that supply our gas at work developed a rather large water heater for a veneer soak tank (1500 gallons of water) it uses two high velocity forced draught burners, “blowing” into 6”diameter stainless submerged tubes

During the r&d program they demonstrated the system working for us at their plant

They fed the vaporizer with liquid propane , from an industrial tank I guess about 500 kg the vaporizer converted the liquid to vapor, with sufficient pressure and flow for these burners

As I recall it was not much more than an insulated box with a small gas burner in the base and I assume a heat exchanger , this was a professionally produced device , cant remember the make, and to be honest I did not give it much attention ,

The other common use of vaporizer devices is for gas powered forklift trucks , they are also fed liquid propane , the vaporizer is electrically heated during start up then heated by the cooling water of the engine during normal running

I cant be more specific about pressure flow etc and I am sure These devices are expensive however it may be something that can be duplicated , to produce large quantities of vapour at an adequate pressure

I am thinking a 8” diameter sch 40 steel chimney with a gas burner in the base and a long piece of ½” copper tube coiled up inside as the vaporizer , coming off the top of the coil would be the vapor line to a Ball valve or whatever

Well that’s my input , hope it helps

[hagent]

Hi Berry,

A real work of art!

On one of your photos there seemed to be enough propane at least for a start. I noticed that alot of fire was coming from one or two of your intakes.

Before making any more modifications I would try and set up your air at all three intakes.

I think that this will help you the most. At least you will have ruled out this factor.

Also try starting your propane amount to where you hear bangs and then increase the amount of fuel from there. If you don't have any bangs then you either have to little or too much propane.

Good luck!

[larry cottrill]

Larry,

thx for your response thats about the same what i was thinking i have to figure out a way to get the flow to the engine a bit better with less narrow points in it and maybe even remove the needle valve and use the valve of the bottle for regulation and only leave the ball valve up there just to use that in case of emergency.

Berry, for my "standard FWE size" engines, I have eliminated the needle valve altogether, and just use the (quite small) ball valve for throttling. I find there is really nothing wrong with this; the only "problem" is you have to get used to the extreme nonlinearity of the valve action. But, that just takes some practice - I don't even have to think about it now.

Of course, I still use my high-flow regulator for these fairly small engines, so the pressure on the valve is 22 PSIG (1.5 atm) maximum - it would be VERY difficult going from tank pressure, because the engines are so small. On a big engine, with a reasonably sized ball valve (NOT the biggest one you can put in!), reasonable range could be obtained. Ideally, the ball valve fully open would provide just a hair more than your total fuel pipe cross-sectional area.

If I ever get back to really tiny engines, I will set up the needle valve again, of course, because in that case, even my little ball valve would be way too sensitive for the fine adjustment needed. I think my valve is sized for nominal 3/8-inch pipe (about 11 or 12 mm ID, actually).

Incidentally, I think Hagen's idea of providing approximately equal starting air at all three intakes is an excellent suggestion!

L Cottrill

[Graham C. Williams]

Hi.
Get the motor humming with the hand-held Rossco injectors then gradually introduce the main injectors. It worked for us.

Graham.

[Berry]

I made another try today but i don't think the lady will run .

The nearest thing that would sound a bit like running is achieved when i put lots of air in the intakes at high speed but the lady won't breath on its own.

Maybe 3 intakes give to much turbulance i am out of ideas now.

So i am thinking of taking it apart .

I really thought it was a nice pulsejet to see but i have to think of some other things to make from the material now.

My wife wants a stainless sculpture in the garden with running maybe that is an idea for the material.

[larry cottrill]

Nuts! Well sir, I can't blame you. You certainly gave it a nice shot, especially in terms of building technique! Man, if I had any disposable income, I'd offer to buy it ;-) Of course, the shipping cost would be a real trip.

If you make a nice bird bath or something, be sure to post a couple of shots of it in place in the garden or wherever. It's really sculptural as it is, especially with such beautiful forming and welding.

Thanks, sincerely, for all your effort. I'm sure you gave it a good shot at working.

L Cottrill

[larry cottrill]

Hi Berry
Awwwwww yours is prettier than mine....
I have come to the conclusion the angle on my intakes is too steep.....from hrs of trying...so the next step is to decrease the angle and try again...Larry sugestions..pls....I haven't had time for sketch it out yet.
Great work Berry

Vern -

Well, what do you think, now? Think maybe I've bitten off a little more than I can chew this time, or do you still want to forge on? I certainly have no magic in terms of seeing what the hidden flaw to the design might be. I keep wondering if there's something about fueling in the middle of such large intake streams that could be a problem. Maybe fueling needs to be taken way in to the region where the air stalls and turbulates, as in the (usually big) Lockwoods. Or mixing path length ... or something ...

I have no problem with your changing the pipe angles, but be sure to pay attention to what worked well on your Lady Jane and try to reason out why that was so successful there. It would not surprise me if that turns out to be secondary in importance to the fuel spout location, though. Maybe also the fuel spray pattern - perhaps you need to go all the way to a fully distributed conical pattern, like the ones from James I will deliver. With your reduced total intake area, you will definitely have pretty high intake air velocities, which means the incoming air streams will project well into the chamber space before things turn chaotic.

Lots of "maybe this ... maybe that ...", I'm afraid. Sadly, I have no "hands on" experience with bigger engines that might render me actually helpful.

L Cottrill

[larry cottrill]

Vern -

If your problem seems to you to be similar to Berry's, a quick and (fairly) easy thing to try would be to put a big washer turbulator in front of each transition pipe, like the one I used on the "front loaded" Lady Anne. This wasn't enough to get that engine going, and is a real "brute force" technique, but it made a BIG difference in how the engine behaved under starting air.

It is nothing but forcibly "putting on the brakes" to the fast incoming air stream, of course.

L Cottrill