Lady Jane Grey

[wakmat]

Hello

I have recently built a Lady jane Grey,What a job!,All hand formed 1mm mild steel and arc welded.
I have stuck very close to the plans,but I'm having no luck starting it,Injectors are 6mm copper flared and pinched like in the 32inch twin stack forum and they are about 1.25" in the intakes,I have a new gas cylinder,and have tried varying air pressures but with no luck.I do get a slight hum/rumble when forcing air in and did manage to get it to sustain using acetlyene.
Any help would be great.
Here is a couple of pics

[larry cottrill]

wakmat -

Man, a beautiful job! All right, you've proven that it can sustain. There's no good reason that you should need a highly energetic fuel like acetylene to get her to run, though. Do you know if propane is "pure" propane in your area, or if it is a blend of propane and butane (yes, believe it or not, this is apparently what you get in some places!)? That might make some difference, though an engine this size ought to run on about any flammable vapor you can imagine.

I realize that I don't do a good job of recommending how fuel setups should be done when I design a new "speculative" engine -- I wait for someone to build it and figure out what works best. However, in this case it seems to me that the spouting end of your stingers should be MUCH farther in, and that is the next thing I would try: Get the stingers to spout just at the point where the intake ducts "elbow" in toward the chamber (or maybe a fraction of an inch short of that). On an engine this size, fuel placement can be fairly critical (of course, that can be true in ANY size). Make sure the spouting point is well centered in the duct cross-section! (But, you know that.)

Let's see if "Vermin" Vern will show up to help us out, since he's the one who has successfully built this Lady before. However, I'll bet he'll agree that your fuel placement is somewhat "shallow" and needs to be farther inside the pipe. Your intake flares seem to me to be just enough to get by; enlarging them might be helpful. But, that is just a guess based on their appearance. This is not to criticize your basic crafstmanship, which appears excellent.

That really is a nice looking build of the Lady Jane. Good luck with her!

L Cottrill

[wakmat]

hello

I have rebuilt fuel system, it is now centred and adjustable, tried temperary larger intake flares with some improvement instead of going from rumbling back to nothing, it takes a few seconds to stop rumbling, so i must be on the right sort of track. will try more permanent flares tomorrow. any help would be great (vern)

Thank you
Tim
Ps here is a jig I used for making those intake scallops,It worked really good for something so simple

[Vermin]

Hey nice job this Lady will rock......... keep small children farrrrr away...........she is very touchy about fuel I used a flared and pinched injector (style name?) @ 1.5" inside intake ducts ....Lots of fuel and air to start once sustaning...its easy to throttle....
Pics
V

[larry cottrill]

wakmat -

OK, so Vern's spouting point is not very far from what you used. That surprised me, but notice that he's using a flattened, high speed nozzle end on the stingers. Duplicate that and I bet you'll have what you need! Try to get the two stingers pinched exactly the same. And, make sure they are well centered in the intake pipes. You should even try to get the lengths of the two stingers the same (from where they manifold together to the nozzle end) if possible, especially if the tubing diameter is small.

Another thing that isn't mentioned much is that the stinger should end up being the most restrictive part of the fuel circuit. In other words, don't use a 3/16-inch ID hose to try to feed a pair of 1/4-inch tubing stingers or something. Not a very good description, but I think you see what I mean.

If I'm reading him rightly, what Vern has here is just a little lower flow speed (meaning right at the nozzle exit) than a Rosscojector would be.

L Cottrill

[Vermin]

Hi Larry et al
I had tried high velocity (pinched and linier) injectors with this unit without success, I would think that a radial type would work as well and probably better, the fuel needs to be dispersed transversly within the intake due to the volume (area) of the ducts...hope this helps.
V

[wakmat]

Hello

Thanks for the tips,I have been trying to start it with fairly low fuel feed and air,I will try feeding it sum more tomorrow.Also looking at you intake picture your flare is double what mine is,I will definitly add some more to my flares as well.
Thankyou Vermin and larry I will let you know how I go.

Tim

[larry cottrill]

I used a flared and pinched injector (style name?) @ 1.5" inside intake ducts ...

Perhaps by this you mean my "lemniscate" nozzle.

I had tried high velocity (pinched and linier) injectors with this unit without success, I would think that a radial type would work as well and probably better, the fuel needs to be dispersed transversly within the intake due to the volume (area) of the ducts...hope this helps.

Sorry I misinterpreted your description and the photo. Yes, I think this is the "lemniscate" type made by flaring the end and then pinching together in the middle. Is that the technique, Vern? If so, then, yes it would be a low to moderate flow speed nozzle, with significant dispersion.

Again, wak and Vern, sorry I mis-stated what Vern was showing us here. Sounds like a good candidate for a pair of my Simpl-Jectors, if they were properly built (my prototypes were highly defective, with very uneven flow patterns, but I'll try to re-post the picture here anyway).

wakmat, if you have a little spot welder you can make a pair of these that should work -- my idea of a plug weld on one side was poor, but if the 1/4-inch brakeline was pinched over the (properly centered) screw and then spot-welded clear through, there would be no uneven distortion. You hold the gap with tin foil while welding, then remove it. That's all there is to it. If you make the pinch by working in gradually and equally from both sides, you end up with the screw (a coarse thread wallboard screw) self-centering as you turn it in through the foil shim! Don't turn the screw down tight, or you'll have a tough time getting the foil out of there cleanly -- just run it in until you feel it center the screw head in the flared end.

Thanks, Vern!

L Cottrill

[Graham C. Williams]

Dear Larry.
What do you think? It looks to me as if the induction pipes are an inch or so too short. I'm comparing this motor with the The VIII Rev06 motor of James D. Perhaps an adjust able section in the induction pipe would help.

Graham.

[larry cottrill]

Dear Larry.
What do you think? It looks to me as if the induction pipes are an inch or so too short. I'm comparing this motor with the The VIII Rev06 motor of James D. Perhaps an adjustable section in the induction pipe would help.

Graham.

Graham -

At first glance, the intakes do look small and short. However, they are almost identical to the way Vern built his and got it running successfully. I think the dual intake aspect of the design changes things enough that they just "don't look right" even when they are. (I thought the ones on James D's smaller motor looked awfully long, but that worked fine there.) I do agree, though, that I would rather see such radical designs built with some simple length adjustment, and I would recommend that in the present case if it weren't for the resemblance to Vern's successful build. As things stand, I think it will probably run, though of course without tunability you can't really tell how close to optimum performance you might be. On this kind of engine, a few mm here or there can really mean a lot, as you know.

L Cottrill

[PyroJoe]

I noticed in Anne, the injector position worked best out of the main stream nearest to the body. Anne is a much smaller duct, but maybe it would be worth a try.

Here is the method I use to start Anne:

1. Light the tail, have a lazy flame about 8-10 inches.
2. Apply SLIGHT air pressure in the intake, then light the intake. (now I should have the chamber rumbling.)
3. increase air just slightly, the rumble will sound weaker
4. increase the propane slightly, the rumble will get loud, and is difficult to control, just on the edge of rich flameout.
(duct is heating)
5. slight bit more air, the rumble is less pronounced
6. slight bit more propane, rumble is strong, starting to bang with occasional single locked pulses, little more propane till she locks in. sometimes she will go rich and flame out.
7. if she stays locked your in good shape, shut off the air. If she flames out after a few seconds then onto #8.
8. apply just a slight bit more propane after lock in then shut off the air.

I hope this helps.

Joe

[Vermin]

I think Larry may be able to supply a vid of the starting up procedure (mine went when the dam comp crashed), and I believe there may be one on U Tube as well.....all this gab makes me want to fire her up again...having a younger sister and all You should fasten everthing down in the shop and open all doors and windows...soft foam ear plugs under muff style ear protectors are recomemded...NO BS
V

[larry cottrill]

To see vern start her and run her out, just go to
http://www.jetzilla.com
and click on the videos. Enjoy!

L Cottrill

[wakmat]

Hello

Have since tried bigger flares and a more spread injector still with no luck,The only progress I seem to get is when I flatten the injector so it has a high speed output,this seems to be the case why acetylene seems to work as well,because of the high speed gas drawing air in.I don't think our gas cylinders over here have a high enough flow for this engine.My fuel set up has no regulator and is 1/2' copper that splits to 2 1/4' injectors.Also It is hard to get the combustion to move out of the intakes into the combustion chamber even with air being forced in.Any thoughts about where to go from here?

Thankyou

[Jutte]

Hi Wak - your LPG cyclinder should be OK ...as I am over the Ditch from you here in NZ.
Notice you mentioned that the combustion was in the intakes...just my two cents worth
...try increasing the intake lengths with some pipe that can slip down the intake.
I have found that I could move the combustion site in my Marconet by increasing or
decreasing the tail pipe length or the intake length-which might not be applicable to your
engine -I don't know if this is correct or not, but perhaps your tail pipe is 'overpowering' the intakes and pushing the combustion site back...who knows?.. all I know
that it's a real pain when nothing seems to work.Also check for leaks.
Hope that helps...it could be something as simple as increasing the intake lengths...good luck!