Slow Ramp to JetA?  
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All Forums >> RC Airplanes >> RC Jets >> Turbine Clinic >> SimJet Turbine Direct Support >> Slow Ramp to JetA?
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Slow Ramp to JetA? - 7/11/2005 3:02:16 PM   
jetjockey


 

Posts: 255
Joined: 1/4/2002
From: Lubbock, TX, USA
Status: offline 		Kevin, Ed, I'm flying my SJ 3000 on a new Rookie. The engine has been on the shelf for a couple of months, but always started fine with a quick propane fire off, and then in a few seconds, would ramp up on Jet A. I put the 3000 in my new Rookie last week, and as usual, the first start was quick on propane, but took a few minutes to prime the Jet A lines, but once it did, took off as normal. Now, since the first slow start, every start is very slow to ramp up on Jet A even though the lines are full of Jet A. Clean filters, new lines, etc. The pump doesn't seem to be starting very early in the start cycle as though the engine isn't coming up to temp, although I checked the EGT probe, and it is in the proper position. The engine starts immediately on propane, but takes between 20 - 30 seconds of propane before it lights off on Jet A. This was not the case before I took it out of service for the 2-3 months, and then put it back in service in my new Rookie. My start procedure hasn't changed from before I put the engine on the shelf, to now that I'm running it again. I'm using standard butane with the regulator you guys are selling. I have not tried to start the engine with my home-made regulator (which would put much more butane in the system faster than the regulated amount). I've also tried a new bottle of butane with the same results using the regulator. I may try my homemade regulator, but it is a little more difficult to start the engine since it is really easy to put too much propane in the system using it instead of your regulator. It appears to me that the engine isn't coming up to the proper temp for a while and the pump isn't starting until it does. Any Ideas? More propane? EGT probe is on the bottom of the exhaust cone when the airplane is sitting on its wheels and extends into the cone about 1/4".

Other than that, the engine is running fine once it gets to the Jet A, and pushes the Rookie around great!!! I really enjoy flying it - frankly I think I fly this engine more than all my others put together.

Thanks, Les Morrow

_____________________________

Les Morrow
       Post #: 1

RE: Slow Ramp to JetA? - 7/11/2005 3:16:26 PM   
rcav8tr


 

Posts: 965
Joined: 12/18/2001
From: Milton, ON, CANADA
Status: offline
Hi Les

I'm glad to hear your enjoying the engine so much, despite the slow starts. Can you tell me which fuel pump you have. I believe the problem is with the pump, but I need to know which make and model before I can trouble shoot further.

Sincerely,
Ed


_____________________________

Ed Miedzybrocki - Great Northern Models - 905-320-7979
Dealer for SimJet, Skymaster, BVM, JetCat, Yellow and much more.

(in reply to jetjockey)
       Post #: 2

RE: Slow Ramp to JetA? - 7/11/2005 3:28:14 PM   
jetjockey


 

Posts: 255
Joined: 1/4/2002
From: Lubbock, TX, USA
Status: offline 		Ed, it's the same make and model that normally comes with the engine. I purchased a new one fairly soon after I got the engine to replace the old one that Kevin said was problematic. It was out of warranty, and I opted to get a new pump (cheaper than a crash!). I haven't tried to water clean the pump (forgot about that). I have the pump where I can put my finger on it, but I don't believe the pump is running for a while after the propane light off, since I can't feel any vibration with my finger until it does start. Also, the plug that goes into the ECU may not be seating and staying in, because the little keeper is questionable, however, once the engine is running, it doesn't falter until I initiate shutdown, so I don't think the plug is the culprit, but I have reached back and pushed the plug home to make sure while I was waiting for the switch over. Can't say if I did any good or not, but suspect the plug is seated since I have no problems with engine stoppage later in the flight.

Hope this helps with the diagnosis.

Thanks, Les

_____________________________

Les Morrow

(in reply to rcav8tr)
       Post #: 3

RE: Slow Ramp to JetA? - 7/11/2005 7:12:43 PM   
rcav8tr


 

Posts: 965
Joined: 12/18/2001
From: Milton, ON, CANADA
Status: offline 		Hi Les

You could have one of two pumps. Either the Flightworks(Brown) or Hausel(gray). If it's the Hausel, the water cleaning and oil cleaning should do the trick. If it's a Flightworks, then there is somethng else we can do. We had both of these pumps coming for a while as SimJet transitioned from one to the other.

Ed

_____________________________

Ed Miedzybrocki - Great Northern Models - 905-320-7979
Dealer for SimJet, Skymaster, BVM, JetCat, Yellow and much more.

(in reply to jetjockey)
       Post #: 4

RE: Slow Ramp to JetA? - 7/11/2005 10:28:05 PM   
jetjockey


 

Posts: 255
Joined: 1/4/2002
From: Lubbock, TX, USA
Status: offline 		ED, my pump is the gray one (Hausel). It seems to run fine when it starts, but seems to be slow starting.

I may try pulling it out and doing the water cleaning trick tonight if I get time.

Thanks, Les

_____________________________

Les Morrow

(in reply to rcav8tr)
       Post #: 5

RE: Slow Ramp to JetA? - 7/22/2005 4:41:02 PM   
jetjockey


 

Posts: 255
Joined: 1/4/2002
From: Lubbock, TX, USA
Status: offline 		ED, I pulled the pump last night and did the water trick, and there was some minor staining of the water. I put a "D" cell battery on the pump motor and ran it for about 10 minutes under water. I kept the pump full of Jet A with a close loop of tubing and ran it under water, but did not get water into the pump itself. After about 10 minutes, it seemed to be more free than before, so cleaned everything up, and put it back in the airplane. No difference in starting ramp to Jet A - still very slow. Then I checked the thermocouple, and found it to be coated with carbon - cleaned it with steel wool like the manual said - tha fixed the problem. It now ramps up almost instantly from the propane to Jet A. Good to know!!!

Problem solved.

Thanks, Les

_____________________________

Les Morrow

(in reply to jetjockey)
       Post #: 6

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All Forums >> RC Airplanes >> RC Jets >> Turbine Clinic >> SimJet Turbine Direct Support >> Slow Ramp to JetA?
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