Hey,

Any of you guys ever had your two engines sharing a common propane tank teed off to the respective solenoids? Any problems?

Yes, this was the set-up on my F-14 with Bees. The only problem was an occasional engine not starting (and it would always be the same one). You could definitely tell the one engine that started very "soft", this would be the one that did not get enough propane. The propane has to be consistent, so when the bottle gets low or the temperature is low, you may experience it more often. Powermax would probably be more consistent. Which engines are you using? I have twin Merlins right now and am still getting the propane figured out on them, but they are using single propane source at the moment, but may "T" them when it is all said and done.

Shaun,

I have my Mibo A-10 set up this way, works fine.

David S

Hi Shaun,
It didn't work on my Rafale. Propane gets too cold due to the high rate of evaporation; thus, dropping the pressure, or even freezing.
Probably a big tank will solve it, but then, two smaller tanks may be easier to install, I guess.

Jack

In any case, if you have easy access to the individual ECU to receiver connectors, you can disconnect and reconnect the engine that did not start and retry to start without having to shut down the other one. (If the propane got too cold, it will not start anyway)
On the 12X (I guess on any 12 ch tmtr) you can program to start each engine individually. By using a three position switch you can select either one, or both, holding in idle the non selected one. Throttle trim and stick will be active for the selected one only.
This is a complex program and uses 3 channels if I recall correct. So, unplugging and replugging the ECU connector is a lot simpler.

Jack

Shaun,
if they are JetCat's, there is a setting in the ECU that enables you to start one engine after the other, the sequence is a combination of the throttle stick and the AUX channel, looks easy enough to do

Shaun

have you considered using an external propane tank? it's one less thing to stuff into the jet and achieves the same purpose.

got pix of the jet? bring it to Tucson

cheers
buck

This is correct, however, you still need to be able to disconnect power to the ECU's individually in case you get a bad start and need to re-set an ECU (without shutting down the other engine). Just make the power connection to the ECU's or a plug/switch somewhere in-line accessible.

FYI, feeding two propane solenoids from one tank works fine with my A-10.

Craig

Guys,

Thanks for the info. I typically get five or six starts off of one JetCat-sized propane tank, so I imagine I can get two twin starts. That would be more than satisfactory. I guess I'll have to keep the lines/distances as short as possible to help keep from chilling everything.

Buck,

Lemme check to see if that warrant from Texas has been vacated. I'm pretty sure it's been 7 years, so the statute should have run out by now.....

7 years sounds about right. it's been 6 years since i was there.

crazy how time flies

bring it to tucson!!! i need some motivation to finish mine. it's more than 85% ready. just gotta stuff it and glue vertical fins on.

finishing can come later.

uggghh soooooooo spoiled with these gosh darn pre-painted, add water, stir, shake box new fangled jets.