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Merlin Turbine support forum now open - 5/17/2005 2:52:42 PM   
RCadmin



Posts: 13181
Joined: 11/28/2001
From: Belle Mead, NJ, USA
Status: offline 		Support for the Merline turbines will be provided here in this forum. Post your questions here and Todd Witkoff of DreamworksRC.com will field them.

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       Post #: 1

RE: Merlin Turbine support forum now open - 12/8/2005 5:39:43 AM   
AFFORDABLEPARTY


 

Posts: 13
Joined: 8/13/2005
From: hamilton, UNITED KINGDOM
Status: offline 		I have a problem. When i start my merlin (new 160) it throws out flames as the engine ramps up.

Is this, what is commonly referred to as a hot start.

The pump start ramp is set at 3 and the pump start point is set at auto-8

The flames only occur during start ups and then clear up with in 5 - 10 seconds

looking for help

(in reply to RCadmin)
       Post #: 2

RE: Merlin Turbine support forum now open - 12/8/2005 2:31:01 PM   
lov2flyrc



Posts: 4565
Joined: 12/6/2001
From: New Smyrna Beach, FL, USA
Status: offline 		From your description, It sounds like the propane pulse rate may be a bit too high. Are you using Powermax or Propane for your starting gas?
Give me a call @ 386-852-4793 and I can walk you through the propane volume adjustment.
Todd

_____________________________

Owner/President: Dreamworks Model Products LLC
www.dreamworksrc.com 386-852-4793

(in reply to AFFORDABLEPARTY)
       Post #: 3

RE: Merlin Turbine support forum now open - 12/8/2005 6:05:39 PM   
Samir


 

Posts: 9
Joined: 1/14/2005
From: Dubai, UNITED ARAB EMIRATES
Status: offline 		I have had my Merlin for over a year and initialy it also through such a huge flame that in nearly destroyed my Euro Sport Typhoon, the gas tank is massive and if mounted horizontally in the fuselage you'll be gettting lots and lots of liquid propane and hardly any gas even if you adjust the flow.My friend suggested that we mount it verticaly and bingo probem solved instantly .It had been orking reliably ever since, try it and see!!


(in reply to AFFORDABLEPARTY)
       Post #: 4

RE: Merlin Turbine support forum now open - 12/12/2005 12:36:57 AM   
AFFORDABLEPARTY


 

Posts: 13
Joined: 8/13/2005
From: hamilton, UNITED KINGDOM
Status: offline 		well got rid of the flames on start up. tried turning down the propane, but it didn't correct the problem.

we then delayed the pump start up time and reduced the pump ramp time. no more flames or kerosene spitting out the engine.

unfortunately, that was only one of our problems.

Truthfully. about ready to throw the engine in the trash.

the other problem that we have is the inconsistancy of the engine.

this morning we started the engine three times in a row and this is what happened:

1. The first time it ran and and spooled up to maximum rpms no problem. thought all was ok.

2. The second startxt start. engine fires up idles no problem. But shuts down as i advanced the throttle (about 3/4) Puff of white smoke.

3.The third time it starts accelerates to full throttle was cycled twice between idle and 100% then the engine started to burn funny- throwing out a 3 -4 foot blue and yellow flame,. the rpms were fluctuating between 24 and 34 thousand rpms. I shut the engine down when i saw the end cone start to glow red.

One of the problems is that so much is happending it is difficult to keep track of all the rapidly fluctuating numbers. Therefore, it is somewhat difficult to give the techs all the correct info so that they can help with the diagnosis.

just a though perhaps i will try and remove the data box from the plane once it says running. perhaps it giving off some interference. Hey, willing to try anythig at this point.

This engine is about three bad starts from the hammer an trash. NO JOKE

For the record, the engine starts up and idles lovely. if we could just get the plane to take off and land at idle i wouldn't be so angry.

P.S. the techs are great, in that, they are extemely helpful and have offered tons of advice.

by the way, we operate at sea level. (the highest point in bermuda is 375 feet above sea level)
todays weather

hi - 71 degrees F
lo - 62 degrees F
barometric pressure 1013mb (29.94"
humidity 94 percent

perhaps this will help

< Message edited by AFFORDABLEPARTY -- 12/12/2005 1:00:16 AM >

(in reply to Samir)
       Post #: 5

RE: Merlin Turbine support forum now open - 12/12/2005 4:51:12 PM   
jetway


 

Posts: 34
Joined: 6/1/2005
From: Hamilton, BERMUDA
Status: offline 		started the engine this morning - ramped up to idle no problems.

applied throttle slowly, the engine began to accellerate and then started to burn funny, blue and yellow flames coming out the end cone. the engine rpms fell and began fluctuating between around 24000 - 26000. the end cone started to turn red.

at the time exhaust temperature droped down to around 480 degrees and the pump Pw reading said 286

i shut down the engine by turning off the fuel

at start up the the exhaust temp. read 24 degrees

prior to running engine made reccommended changes to the various parameters as laid out by gasper and increased to the accelleration delay.

started the engine a second time and the same problem occured.

is it normal to have soooooo muuuuch trouble dialing i a turbine, or is it just the merlin.

at least it looks impressive.

(in reply to AFFORDABLEPARTY)
       Post #: 6

RE: Merlin Turbine support forum now open - 12/13/2005 4:25:10 AM   
lov2flyrc



Posts: 4565
Joined: 12/6/2001
From: New Smyrna Beach, FL, USA
Status: offline 		Your fluctuations and innability to accelerate are most likely from a sticky fuel pump. Tailcone got hot as the rpms fell below the minimums for the engine to sustain combustion.
Both problems you describe are most likely related to the bad pump, I'll let you know what I find as soon as we get the engine back for inspection.
Regards,
Todd

_____________________________

Owner/President: Dreamworks Model Products LLC
www.dreamworksrc.com 386-852-4793

(in reply to jetway)
       Post #: 7

RE: Merlin Turbine support forum now open - 12/14/2005 3:14:26 AM   
AFFORDABLEPARTY


 

Posts: 13
Joined: 8/13/2005
From: hamilton, UNITED KINGDOM
Status: offline 		For the record, so far we have received first class service from the merlin support staff. Hopefully a replacement pump will rectify the problem.

Now that there is light at the end of the tunnel, I am once again looking forward to seeing this beast in action. Just imagine 38 pounds of thrust on a 12 pound enforcer.

peace and luv

< Message edited by AFFORDABLEPARTY -- 12/14/2005 7:18:15 PM >

(in reply to lov2flyrc)
       Post #: 8

RE: Merlin Turbine support forum now open - 12/16/2005 12:12:56 PM   
AFFORDABLEPARTY


 

Posts: 13
Joined: 8/13/2005
From: hamilton, UNITED KINGDOM
Status: offline 		well, we heard back from Todd today, the engine appears to be working fine on the test bench. He is of the belief that, our fuel supply system may not be flowing suffient volumes of fuel.

Inorder to test his theory, I'm gonna build a test bench with a new uav, tanks and hoses.

I'll post the results.

On another note, i just thought i would say hi to the fellas that are keeping track of the post (chat,the sherrif,woodley, and frank.


we will be back. just watch the skies. don't blink u might miss it.

(in reply to AFFORDABLEPARTY)
       Post #: 9

RE: Merlin Turbine support forum now open - 12/17/2005 3:36:07 AM   
lov2flyrc



Posts: 4565
Joined: 12/6/2001
From: New Smyrna Beach, FL, USA
Status: offline 		Derek,
I Have performed several runs on your engine, I can confirm the problem you where experinceing is not within the engine or ancillary components. Your Merlin runs perfectly in our test stand. As you can see from the image below, a graph was created from your Fadec Data before I began testing your engine. From the graph, we can see you throttle command rising, fuel pump command rising but temps and RPM dropping. This is a classic example of inadequate or restricted fuel supply to the pump. We see this same pattern over several of your runs. I suggest a through check of the aircraft fuel system. Test runs on the stand will confirm your engine is running correctly.
Your engine is on it's way back to you now...
Regards,
Todd

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_____________________________

Owner/President: Dreamworks Model Products LLC
www.dreamworksrc.com 386-852-4793

(in reply to AFFORDABLEPARTY)
       Post #: 10

RE: Merlin Turbine support forum now open - 12/17/2005 4:37:19 AM   
MLaCoste



Posts: 813
Joined: 8/29/2002
From: Roseville, CA, USA
Status: offline 		Nice job Todd

First class service!

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(in reply to lov2flyrc)
       Post #: 11

RE: Merlin Turbine support forum now open - 12/17/2005 1:17:34 PM   
AFFORDABLEPARTY


 

Posts: 13
Joined: 8/13/2005
From: hamilton, UNITED KINGDOM
Status: offline 		Good day Todd,

I would like to take the opportunity to thank you for all of your time and patience.

On another note, i was wondering if it was possible for you to post a graph-taken from an engine that is operating correctly.

This would serve as referrence guide for when we check the engine data in the future.

Thanks




(in reply to MLaCoste)
       Post #: 12

RE: Merlin Turbine support forum now open - 12/17/2005 2:59:43 PM   
jetway


 

Posts: 34
Joined: 6/1/2005
From: Hamilton, BERMUDA
Status: offline 		Hello Todd,
I would also like to thank you for your time and patience.
Irvin and i figured it would be best to send the motor up
to you rather then have everyone here poking with the
motor.We would go through the system on this end as
WE would like to understand the whole operation of the
system ourselves motor & etc.
Great Service.
Jetway.

(in reply to AFFORDABLEPARTY)
       Post #: 13

RE: Merlin Turbine support forum now open - 12/19/2005 7:04:48 PM   
lov2flyrc



Posts: 4565
Joined: 12/6/2001
From: New Smyrna Beach, FL, USA
Status: offline
quote:

ORIGINAL: AFFORDABLEPARTY

Good day Todd,

I would like to take the opportunity to thank you for all of your time and patience.

On another note, i was wondering if it was possible for you to post a graph-taken from an engine that is operating correctly.

This would serve as referrence guide for when we check the engine data in the future.

Thanks


Well, Since I sent your engine back and did not dowload the data before sending it, I am just pulling data here from another ecu I have on hand. This chart looks fairly typical of a "Normal" run, meaning all systems are working correctly. I do notice from this file that the temps are a bit higher than normal (for a Merlin) on this run, most likely due to the TC being inserted too deep in the nozzle. But... Should give you a good idea what a normal run would look like.
Todd

Attachments
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_____________________________

Owner/President: Dreamworks Model Products LLC
www.dreamworksrc.com 386-852-4793

(in reply to AFFORDABLEPARTY)