Jett 90LX/ Cline
 

Has anyone run a Cline regulator with a Jett 90LX? And what were the results?

RE: Jett 90LX/ Cline
 

The Jett engines I have, run sweet without anything, imho adding regulators or pumps just complicate things, doesn't hurt to try it though.

RE: Jett 90LX/ Cline
 

My .90 lx runs perfect, even with long lines. Can't think of a setup that would need it as they tend to give quite a bit of back pressure.

RE: Jett 90LX/ Cline
 

The airframes are Atlanta 60’s, 80’s patternships that were designed around the YS 60’s. The tank location is the problem. The tank is located above the spray bar and causes flooding without a regulator. This is the only location for the tank, even if relocated at the CG it still will be too high. The motor is inverted to make things more challenging.

RE: Jett 90LX/ Cline
 

What about a bladder tank for your Jett engine?

RE: Jett 90LX/ Cline
 

I don't think a bladder will help his flooding issue, it may even make it worse.

RE: Jett 90LX/ Cline
 

I’m a fan and firm believer in the bladder tanks( Jett / Tettra ) for consistent fuel delivery but in this installation the flooding, I assume would worsen because of the efficiency of the system. That bring me to another question, would it be feasible to use the bladder tank with a Cline/ Iron bay regulator?

RE: Jett 90LX/ Cline
 

Using what pressure source?

MJD

RE: Jett 90LX/ Cline
 

Using the crankcase pressure. The Cline/ Iron bay both use crankcase pressure to the tank instead of muffler/pipe pressure.

RE: Jett 90LX/ Cline
 

Okay, bladder tanks will work with positive pressure systems just fine, so long as precautions are taken to keep the tank together, like filament tape or whatever is needed. The bladder sees nothing, don't worry about the material bursting or anything like that.

MJD

RE: Jett 90LX/ Cline
 

why not ask bob27 his opinion or contact dub himself

RE: Jett 90LX/ Cline
 

Would it help to route the fuel line with a loop that is higher than the fuel level?
This might not be "high-tech" enough for some guys, but it has worked for me....;)

RE: Jett 90LX/ Cline
 

I was hoping that bob27 would see this thread and chime in eventually. I was just looking for personal experiences with a 90LX / Cline or Iron bay combination. I posted in this forum because this is a high performance set up. I wanted feedback from the knowledgeable people that frequent this forum. I know firsthand that these regulators work, but how about on this particular motor/carb?

RE: Jett 90LX/ Cline
 

I have been thinking about this installation for some time know, I have given it much thought and your idea of routing the fuel line higher than the fuel level is a feasible fix for the flooding problem. The remote needle valve can then be mounted above the inverted motor; the high speed needle would be adjusted from the top of the plane. “High-Tech” or not if it works great.

RE: Jett 90LX/ Cline
 

That would only work until there was fuel in the line and then the siphon principle will take over. It would seem that even after just priming the engine you would be back to square one.

RE: Jett 90LX/ Cline
 

the klines dont allow siphon or delivery, unless there is a vacuum signal present, should work fine

RE: Jett 90LX/ Cline
 

It works if you don't leave a fully gassed up plane that's been primed laying around. If you are waiting for your number to be called while the plane sits ready, keep the line pinched.

RE: Jett 90LX/ Cline
 

If the 90LX is capable of drawing fuel through the spraybar and running on it's own, then it will work with a demand regulator. And it won't flow without demand so it won't flood on the ground. I can't think of any reason the 90LX would be any different than anything else, unless perhaps the demand regulator has trouble delivering a sufficient fuel flow rate which is not likely. From the reverberation of silence here, it doesn't sound like anyone here has actually specifically run the 90LX with a demand regulator. But everything else seems to like them.

Bob is occasionally away from the forum for a day or two, and I have a feeling he might be now.

MJD

RE: Jett 90LX/ Cline
 

Best thing to do is sorta what we use for the racing planes. Keep a hemostat/clamp on the fuel line until you start the engine. Once it is running, typically the fuel flow regulates itself.

The idea of mounting the RNVA up top is probably a good approach too. The engine will not mind the position all that much.


More directly to your initial question......

the 90LX does not work well with the regulators. I have used them, and I have gotten them to work. But it takes about an hour of bench time to become familiar with the setup, to get the needles dialed in JUST right, and to ensure the system functions properly. Plug choice becomes critical. I have also used the iron bay regulators... about the same result.

The problem is, sorta what MJD noted. The Jett carb does not "suck" fuel all that much. It is a pressure fed system. Muffler pressure or pipe pressure is needed for fuel delivery to the carb. Those of you who are Jett owners out there know what happens if the muffler pressure line falls off. So, the Cline and Iron Bay regulators struggled with sensing demand. It only worked by mounting the regulator at (pretty much right on) the carb - between the needle and the carb inlet. Now picture what this looks like, the plumbing, physical mounting..... tis not pretty.

I have also had "some" success with the perry pump, used in a 3-line regulated return setup. Again, a bunch of bench time, adjust the engine first, then the pump and return pressure, and then the engine again. My SJ-50 and SJ-90 engines worked ok with this. The LX engines seemed to not like this all that much - pump delivery sometimes led or lagged behind the demand from the engine/pipe.

RE: Jett 90LX/ Cline
 

Interesting, I recall Dub saying something about fuel draw and transition compared to OS carbs being different. Better on one, not as good on the other. Now that you mention it, it was fuel draw he said the OS had more of, but his transition was better. Ohh.. the dark art and sorcery of carb design... [sm=bananahead.gif]

Yeah, I meant if it could draw fuel from a nearby tank suction only, no muffler or other assist, then it should work fine with a regulator. Guess it doesn't so it won't. But that is pretty much the litmus test for whether or not a demand regulator could be of any value. Gotta have enough vacuum so that the drop from the regulator isn't all you began with.

MJD

RE: Jett 90LX/ Cline
 

Bob,
Thanks for the information on the R&D experiences with the regulator and pump setups. It gives me answers to my questions and more info on my proposed installation. It seems from my interpretation, correct me if I’m wrong that a carb swap of say an O.S. would maybe give me more vacuum to operate the regulator or is it the whole design of the motor that makes it improbable?

I’m very adamant in using JETT engine in these planes, even if I have to clamp my fuel lines until startup. I had to do this back in the 80’s with my Rossi powered Atlanta’s.

What are the dimensions of the carb on the 90LX? Inside diameter/ neck outside diameter.

RE: Jett 90LX/ Cline
 

Carb swap is not really going to help. You will end up with a smaller carb bore, and the engine will not perform the same.

If you have the regulator, try it. Would be a good data point for the application.

I would have to check on the existing carb size. I do know, that no other engine carb drops in. Jett is larger. We turn-down the carb neck dia when a carb is sold for use in other engines.