PyroJoes Recipe for Beginners

PyroJoe · Post by **PyroJoe** » Sat Oct 15, 2011 2:27 pm

Were the injectors crimped? Do they sustain a fast flame outside the engine?
Its best to adjust the injectors off the engine, in open air.
What your looking for is a fast flame volume that would fill the CC volume. If it won't make a fast roaring flame, it won't bring the tail pump online.
It may very well start with one tank, but everything has to be near optimum. Not an easy task.

Small pin holes wont make much difference, if they become larger near 1mm it becomes a problem.

ganuganu · Post by **ganuganu** » Sat Oct 15, 2011 2:59 pm

yes the end of the injectors are crimped. initally when i turn the fuel supply i can see medium sized yellow flames coming out through the intake pipes, when i increase the fuel fast flames are coming out through the exhaust pipe.

PyroJoe · Post by **PyroJoe** » Sat Oct 15, 2011 3:46 pm

Have you tried pulling the injectors out to the flare of the intakes? (trying to achieve a good fuel air mix before the CC)

Possibly as far out as 2cm outside, beyond the flares.

ganuganu · Post by **ganuganu** » Sat Oct 15, 2011 3:51 pm

do you want me to place the injector tip near the flare and try to start the engine..

PyroJoe · Post by **PyroJoe** » Sat Oct 15, 2011 3:55 pm

Yes, remember the intake diameters are slightly under sized. Be careful in doing so. It will need as much fresh air as possible. Are you using starting air?

ganuganu · Post by **ganuganu** » Sun Oct 16, 2011 6:59 am

yes iam using blower to start the engine..

PyroJoe · Post by **PyroJoe** » Sun Oct 16, 2011 4:20 pm

When the injectors are at the flares avoid using the blower to start. The flow of the fuel should pull in enough air to create a good mix. Each injector tip should make a rough hissing sound. Take care in tuning the injectors to match closely. Its easy to have one to rich or lean.

The goal is to create alot of fire in the CC. If it has a roaring fire in the CC for 45 seconds and still doesn't run then more fuel will be needed, or a small reduction in the CC volume. The 24.6cm CC length may need to be shortened to 23cm to drive the tailpump with a small supply of fuel.
Adding the expansion on the tail should help also.

ganuganu · Post by **ganuganu** » Mon Oct 17, 2011 1:43 pm

http://www.youtube.com/watch?v=sezsVrs90fY

i have got a video for you joe. Take a look at it, this video was taken by keeping the injectors at a depth of 5.4cm and the same results were got when i placed the injector near the tip of the flare. When i open the fuel the engine starts with an booming effect and after that when i place the blower at a specific place the engine looks like its running. i dont know but you can see it in video.

PyroJoe · Post by **PyroJoe** » Mon Oct 17, 2011 2:49 pm

The video helps a great deal, thanks!
It sounds close to starting, really nice sound.

Using the blower on one intake appears to create an un balance between the intake ports. It is very important that the intakes are balanced.

I would recommend to not use the blower. Make sure the propane liquid is warm, 32 to 36 Celsius. Place the injectors 3mm inside the flares.

If you need to try the blower again, move it further away (1/2 meter) from the intakes.

metiz, does it sound starved for fuel to you? I think 2 tanks would definitely drive it better.

PyroJoe · Post by **PyroJoe** » Mon Oct 17, 2011 4:00 pm

Inspect the opening on the tank side of the injector body (circled in red). Make certain there is no obstructions or roughness.

It is good to use a tool and slightly increase/flare this end.

If possible use a larger pipe diameter pipe for the first segment. (green line)

metiz · Post by **metiz** » Mon Oct 17, 2011 4:58 pm

It should be able to run off a single, full 7kg propane tank. Maybe the 4 injectors just offer to much resistance for enough fuel to enter the engine. Ganu, you could try hooking up 2 injectors instead of 4 (opposing intakes) and try again.

ganuganu · Post by **ganuganu** » Tue Oct 18, 2011 1:11 pm

i started the engine as metiz said it worked to a extent. I placed the injector tip near the flare the engine looked like it is going to start but didnt. Once i withdraw the blower the engine is not running. check the video.

http://www.youtube.com/watch?v=UE6R_py_RLs

PyroJoe · Post by **PyroJoe** » Tue Oct 18, 2011 3:42 pm

Looks to me that the fuel supply is only able to supply a very low idle. The biggest engine I started with vapor on a single tank had a tailpipe diameter of 5.85cm, and struggled to reach mid-throttle range.

A tail cone may give a quick enough pressure drop to allow the fuel supply to at least sustain the engine.

ganuganu · Post by **ganuganu** » Tue Oct 18, 2011 4:03 pm

so what to do now can i make a cone for tailpipe. can i make like this..

PyroJoe · Post by **PyroJoe** » Tue Oct 18, 2011 4:54 pm

Use 15cm at the opening of the tail cone, that should produce near a 9 degree angle.

www.pulse-jets.com

PyroJoes Recipe for Beginners

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