130r

[jerry marra]

Just a small input,
I built a 130 lbs 4 years ago with negative result.
The original GH-2 15lbs work as specified but once you goe to a double coil nothing but problems! the 130 is very sensitive to propane quality/temp and pressure.

Important is the coil wall thickness,there is no substitute,a heavy wall will prevent the liguid propane from reaching saturated level even if the pressure at the nozzle is correct , the vapor speed and thrust will be decreased considerably and you will not reach the sonic lock.

As the engine heats up the alignment on the three intake stages goe off and a loud sckreching sound is emitted.Unless you get the sonic lock all you get is about 20 lbs of thrust.
.
Also even if you purchased a new engine ,keep in mind that you need a specific orifice just before going into the double coil,if they are wrong or missing you will flood the coil and even if you have the right nozzle pressure the vapor speed and temp will be off.

Even with the 225lbs pressurized propane ,its the vapor speed and temp which is hard to measure since it changes constantly.

All you need is a good hearing and you will know if the tune is there or if its just a pressurized ventury burner .

This is just my opinion on many many hours of testing with the 130.
Stick to the 5lbs and the 15/20 lbs modelThey works fine.

thanks
jerry

[Viv]

Just a small input,
I built a 130 lbs 4 years ago with negative result.
The original GH-2 15lbs work as specified but once you goe to a double coil nothing but problems! the 130 is very sensitive to propane quality/temp and pressure.

Important is the coil wall thickness,there is no substitute,a heavy wall will prevent the liguid propane from reaching saturated level even if the pressure at the nozzle is correct , the vapor speed and thrust will be decreased considerably and you will not reach the sonic lock.

As the engine heats up the alignment on the three intake stages goe off and a loud sckreching sound is emitted.Unless you get the sonic lock all you get is about 20 lbs of thrust.
.
Also even if you purchased a new engine ,keep in mind that you need a specific orifice just before going into the double coil,if they are wrong or missing you will flood the coil and even if you have the right nozzle pressure the vapor speed and temp will be off.

Even with the 225lbs pressurized propane ,its the vapor speed and temp which is hard to measure since it changes constantly.

All you need is a good hearing and you will know if the tune is there or if its just a pressurized ventury burner .

This is just my opinion on many many hours of testing with the 130.
Stick to the 5lbs and the 15/20 lbs modelThey works fine.

thanks
jerry

Thanks for that, there is a lot of secret knolidge contained in your posting.

"you need a specific orifice just before going into the double coil" now that answered a question that had been worrying me about the flow rates in the heat exchanger and its sensitivity to the conductivity of the coil material

Viv