Ok, I know this is a very old topic, but I working on a new jet and have a great running Merlin 180 propane start. The motor only has 3 hours so I want to get some time on it this summer.


All my other jets have kero start. But I was told back in the day you guys used to run propane in the jet. This is an Aviation Design Diamond, and it needs a ton of nose weight, so not worried about weight.

Dose anyone sell a kit?

How do you refill them?

Thanks Mike

I wouldn't use on board gas. It takes up space and is something else to catch fire if you have an accident.

Just use a connector (I used Rectus connectors but Festo make some suitable ones as well) and leave the gas off board in the can. You can either regulate the gas output yourself with a valve on the can or you can have a variable restrictor (Festo again!) in the model. I used the former method but there is bit of a knack to it. It is easy to use too much gas if you're not careful and this can cause a big flame or a big bang!

I am still running 2 propane start jets and I love them.

I'm curious as you say our Merlin runs great and it is propane start. How did you start it before?

Here is how I use my propane start.

I have an onboard propane tank. It came with my engine.

I have a one way 4 mm festo with a "tee" in-between the tank and the propane solenoid. The 4 mm fuel line needs to be reduced to 3mm as that is size of the festo connector on the engine.

That's it.

I get my propane from REI or any camping store that sells it. It is a propane/butane mix usually. Like this:

https://www.amazon.com/Coleman-Butan.../dp/B000PY9T0S

I use the trigger valve to attach to the above propane/butane to connect to the one way 4mm festo. Like this trigger valve:

https://www.rcgroups.com/forums/show...ve-for-propane

Merlin never made a 180 .....?

Sorry 160, I got it from my boy, it was in a Aviation Design Super Scorpion, We used just regular Green Colman Propane outside the jet. But I was thinking If the propane was onboard it would be like having kero start.

I cannot remember exactly where I saw it, but IIRC one of the sanctioning bodies maybe AMA? Came out with a directive to remove all onboard propane systems?

Maybe it's just old guy memory issues, but I know lots of guys removed the propane tanks from their models and that is supposedly why. It is a real fire hazard since it's so easy to light the stuff, if it leaks into the model things could go bad real quick.

Just have the propane bleed back into the engine and you won't have anymore propane in the jet! Voila!

That is just another setting ECU.

on board propain?!?
lol pro-pain lmao



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You can't use on-board propane. Propane has too high a vapor pressure (150 psi at 90 degrees F) and it will blow the hoses off all of your fittings. If you use propane to start, you need to use an off-board gas container with a pressure regulator - like this one:

Dreamworks Model Products LLC

For "gas start" engines (love mine too - no hot starts!), most guys use a 70% 30% Propane-butane mix. That has a lower vapor pressure which is easier on the tubing and fittings. I have, however, converted all of my gas start jets to off-board gas (i.e., no onboard gas tank) its safer, and actually easier - just connect the off board gas tank, turn it on, start the engine, turn off the gas, and disconnect the tank.

I use the same gas Rav does, from REI as well. Unfortunately, the BVM valves are no longer available. I got one from Altecare RC that has a screw valve which works great on those tanks. Unfortunately, they don't sell it anymore. However, I think you could get this one:

http://www.altecare.com/airpropanetankvalve.JPG

And mate it with a 4mm festo valve to do the same thing...

I have an old Merlin 160 Propane start. Very nice motor. Forget the Butane/butane mix, too much aggravation trying to find it. Just buy the Dreamworks regulator. Buy the propane anywhere and enjoy. No onboard tank. It will store too much pressure from any residual propane. Keep it simple.

Thanks Simple it is

Mike,

As the others have said... it's a pain, takes room, and makes for a nice fireball on impact. First, straight propane has too much pressure, so you have to use a mix. Powermax was the standard, but it's no longer available. Also, it will still be marginal on a hot day for line pressure. Second, you still have to carry a bottle around, and you will still have to "Re-charge" the onboard tank before each flight to make sure you have enough gas for a good start. And third, the propane mix full is more expensive.

Because of those 3 reasons... why not just plug the (cheap) propane bottle on for a start? It's not like the old engines could do a re-start, so why have it onboard?

Oh... and since it went out of favor... and since it burns at a different temp (needing a different setting) if you run out while at the filed... chances are, no one will have any. But most of us have standard propane in the flight kit.

Using a onboard propane on this one since 2004... (picture taken today) no fuss, no fire, no drama. just a lot of flights.

Dont want to use it? no prob. it works too.

Enrique.

Hi all, I have too Merlin 160 gas start, and I had another gas turbines and never Install gas onboard because always you need link the main gas bottle before flight and if you connect the gas for fill, why you not start in that moment ? Only for make a full the autostart with the hatch closed ?

Regards from Spain
Carlos

Cmjets

Hola Carlos, como esta?

My ritual is most times the same.. quick check inside the airplane, fuel, air, gas and then take the model to the starting area. flip the switch and go!