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RE: PST contact? - 8/14/2006 2:45:58 AM   
rcguy!



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From: Chesterland , OH, USA
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quote:

ORIGINAL: speedbrake

Dave,
I didn't answer all your questions! The UAT remains full; it has a small air bubble at the top of the tank...and stays about the same size. No obvious leaks visible in the fuel tubing and fittings.
Keith


Keith,
On mine, the bubble at the top got to be 1/3 down. If it remains the same size, ie tiny, then it may be something else.

Dave

(in reply to speedbrake)
       Post #: 26

RE: PST contact? - 8/14/2006 3:54:33 AM   
Kelly W



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Joined: 1/21/2002
From: Delta, BC, CANADA
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quote:


The after shut down display had 135,000 in the #1 position; EGT 395C in the #2 position; PMP 2.84 in the #4 position; and Bat 7.51 in the #8 position. The only * was by the four and eight positions.


Just popped in for a sec... So this means the engine was operating at 135K RPM and an EGT of 395C. The RPM is well within the shutdown safety limits, and the EGT is above the minimum running temp of 250C. On a side note, it does seem on the cool side though so yo might want to check the insertion depth of the EGT probe...

The asterisk in position 4 designates a shut down commanded by the user, or due to a loss in signal. What sort of range are you getting on the ground with the turbine running? To be truly accurate, the model should be a few feet off the ground (using a table for example) and you should hold the transmitter out to the side of you with fill arm extension, and the areal down all the way. If you want to get really picky, test the model at a variety of orientations relative to the transmitter (flying left, right, towards and away from you, etc) and with any whip antennas deflected back to simulate the effect from airflow.

Kelly

_____________________________

Kelly Williams, GTBA #1969

(in reply to speedbrake)
       Post #: 27

RE: PST contact? - 8/14/2006 1:33:29 PM   
speedbrake


 

Posts: 188
Joined: 1/22/2006
From: Fort Valley, GA, USA
Status: offline 		Kelly,
I'll perform a more thorough range check before the next flight. I'm not sure when the glitch counter zeros out, but it didn't have a figure displayed after the last flight.

Did you see the input from Dave? He experienced a problem with the orientation of the main tank, feed line facing aft instead of forward. Could this be a cause. Anyway, he said it cleared a flame-out condition he had. What kind of error would the GDT display for this?

Also, can rapid throttle movement cause a flame-out? I don't think I'm moving the throttle too fast but it seems the flame-outs occur while the model is descending and after the throttle has been decreased, such as coming out of a loop. I fly fairly close in so I've been able to hear the turbine spool down each time a flameout occurs.

Cheers,
Keith

(in reply to Kelly W)
       Post #: 28

RE: PST contact? - 8/14/2006 3:46:45 PM   
speedbrake


 

Posts: 188
Joined: 1/22/2006
From: Fort Valley, GA, USA
Status: offline 		Kelly,
The PST manual mentioned using a whip antenna. Is this the best type of antenna to use? On the R54, the antenna is routed through the fuselage. I could easily mount a whip antenna if that is considered the best way to go.

Keith

(in reply to speedbrake)
       Post #: 29

RE: PST contact? - 8/14/2006 3:54:15 PM   
Kelly W



Posts: 863
Joined: 1/21/2002
From: Delta, BC, CANADA
Status: offline 		Yes, I read that response, but here's the logic... A flame out can be caused by the ECU or external factors. If its caused by the ECU, its due to a falesafe or user commanded. In that case the asterisk is shown in position #4. If the flame goes out due to a bubble or some other reason, it will either show up as a temperature out of limits or an RPM out of limits. Keep in mind, every brand of ECU is like a blind person, it only has a few senses to depend on.... They only have information on the RPM and EGT, that's it... If this particular ECU sees the temp drop below 250C, it knows the flame has gone out so it shuts down the pump, starts the cooling cycle, and displays an asterisk in position #2. If the flame goes out on its own, it can also show up as a low RPM if that parameter happens to drop sooner than the EGT. (They both drop out of limits very quickly...) If the RPM drops out of limits, the ECU also shuts down the pump, starts the cooling cycle, and displays an asterisk in position #1. since you have one in position #4 and the last snapshot of data stated the 2 parameters within running spec, this is a pretty clear indicator that the fuel system wasn't at fault.

RE, whip antennas, the key is really getting the antennae away from the on board electronics such as high current drawing servos, fuel pump, smoke pump (if used), the ECU, ECU pack, etc. Creative positioning of the hardware can often negate the need for a whip, but they do work well. I use them on both of my jets, and will use them on the one's I'm building. Do a search for whip antennas and you'll likely get a good sense of the variety available. Basically, there are the full length ones where you cut down the receiver lead by an equivalent amount, and there are base loaded antennas that are rather short but account for almost the full length.

Kelly

< Message edited by Kelly W -- 8/14/2006 3:56:27 PM >

_____________________________

Kelly Williams, GTBA #1969

(in reply to speedbrake)
       Post #: 30

RE: PST contact? - 8/14/2006 6:26:00 PM   
speedbrake


 

Posts: 188
Joined: 1/22/2006
From: Fort Valley, GA, USA
Status: offline 		Kelly,
Thanks for the response. I obviously have a lot to learn about turbine engines. As I become more aware of the GDT's capabilities, I will know what to look for should future problems occur. I've had four flame-outs so far. The first occurred on the first flight...I thought is was caused by a low ECU battery. But to be honest, I didn't understand the shut down data. Now I think it was the same indication as my last flight (#4 - user shutdown). The shut down occurred about four minutes into the flight, about the same time as the last flight. The next two flame-outs were EGT related. I think I bumped the EGT wire with the exhaust tube (necessary with the R54) and the result was a high EGT reading. The next flight was a low EGT reading because I pulled the EGT wire out too far. It is now inserted about 1/32 of an inch. These two flights were short...about two minutes. Your comment about the EGT being a wee bit low might be a result of the above occurrences.

The current antenna wire runs along the inside of the fuselage. It is several inches away from the ECU and other components. A whip antenna could be installed so that it is further away from all the components. Because I have a whip antenna available, I'll go ahead and install it then perform a thorough range check. The manual states to keep the ECU and receiver batteries separated. This is almost impossible with the R54. There just isn't enough room to move the batteries so they are inches apart. Could this be a cause?

Keith

(in reply to Kelly W)
       Post #: 31

RE: PST contact? - 8/16/2006 4:57:31 PM   
Kelly W



Posts: 863
Joined: 1/21/2002
From: Delta, BC, CANADA
Status: offline 		Hey Keith, with regards to the earlier post about the fuel system...
The J600R has a less significant fuel flow rate in comparison to the 1300R obviously. The 1300R and any other turbine of that thrust class will see a larger benefit from the 6mm lines through the fuse, but its likely not necessary at all for the 600R in a Reaction 54 since the fuel line from the pump will be relatively short.

The UAT comes with a short section of 6mm hose and a fuel dot. This is what I'd used for the filling port. Either that or I'd use the 6mm hose and a ball valve. The connection to your main tank should probably just be a short section of the largest diameter Tygon hose you can find. The only reason I recommend Tygon here is that the outlet tube from the main tank may need to have the hose stretched over it and wire wrapped, and Tygon is much softer and better for adapting... Between the UAT and the pump I'd start with 6mm polyurethane (like the fill port) then switch down (with a Barbed fitting) to 4mm a couple inches from the pump. Exiting the pump, you really don't need to worry about sizing up to 6mm in this case. 4mm line straight to the engine will suffice and still keep your pump voltages within reason. Installing a filter in this area is highly recommended though. I am in the midst of ordering a number of items from Festo and I can grab an extra 50 micron filter for 4mm hose if you like. I don't know the what my price will be but a safe estimate would be $7.00 for now. I'll post a link to the whole price list when I get the chance, but for now here's a few items of interest. I still need to verify the prices from an updated quote so they're subject to change at any time...

4mm 50 micron filter: $7.00
6mm 70 micron filter: $7.00
6mm to 4mm barb fitting: $0.50
6mm clear Polyurethane hose: $6.75 per 3m
4mm clear Polyurethane hose: $4.50 per 3m

4mm to 6mm Festo Union: $4.00
4mm union: $3.50
6mm union: $3.50
4mm Ball Valve: $11.00
6mm Ball Valve: $11.00


Now on the antenna and range...
The battery position could be causing trouble, but it doesn't seem to be much of an issue for the other R-543 owners out there. Basically what we state are ideal 'best practices'. Now, virtually no aircraft kit is ideal when installing all the hardware, so you have to make a few compromises. The most critical item to remove is the fuel pump, followed by the ECU and / or ECU pack.

Lastly, you should be seeing EGT's in the 500's to mid/high 600's. Any less and your probe is likely too far out. I've had one PST user flame out a couple times from low EGT, easily fixed by adjusting the probe depth.

Kelly

< Message edited by Kelly W -- 8/16/2006 4:59:23 PM >

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Kelly Williams, GTBA #1969

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       Post #: 32

RE: PST contact? - 8/16/2006 6:41:28 PM   
speedbrake


 

Posts: 188
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From: Fort Valley, GA, USA
Status: offline 		Kelly,
OK...using you guidance, if I replace the shut off valve with a 6mm valve then the entire fuel system would use 6mm tubing up to the pump. The pump, filter, and turbine would use 4mm tubing. I would need one 4mm/6mm barbed fitting, a 4mm filter, a 6mm shut off valve, and some 4mm and 6mm tubing. When could you ship these items? Provide me with a phone number and I'll call you for further details.

I installed a whip antenna. A range check was performed and no glitches were noticed. I'll perform a range check with the turbine running this weekend. Hopefully this will solve the problem.

Cheers,
Keith

(in reply to Kelly W)
       Post #: 33

RE: PST contact? - 8/17/2006 4:43:07 PM   
Kelly W



Posts: 863
Joined: 1/21/2002
From: Delta, BC, CANADA
Status: offline 		The shut off valve stays at 4mm. In your case I'm saying you should leave it as is after the pump, so it should go: Pump ---> 4mm ball valve ---> filter ---> Turbine... The 6mm ball valve woudl be used on the feed line to the UAT.

My contact info is here. I don't currently have stock of the 4mm valves, but I'm placing the order later today. I have stock of everything else...

Kelly

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Kelly Williams, GTBA #1969

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       Post #: 34

RE: PST contact? - 8/19/2006 1:00:02 AM   
speedbrake


 

Posts: 188
Joined: 1/22/2006
From: Fort Valley, GA, USA
Status: offline 		Kelly,
Success! I flew two times today...no flameouts. The whip antenna apparently remedied the problem. Two six minute flights were flown. The EGT was also much better....reading 480C - 490C before take-off with about 1/16 inch of the wire inserted.

Thanks for the help, I'm going to work on the fuel system next.

Keith


(in reply to Kelly W)
       Post #: 35

RE: PST contact? - 8/20/2006 3:40:16 PM   
speedbrake


 

Posts: 188
Joined: 1/22/2006
From: Fort Valley, GA, USA
Status: offline 		Kelly,
Two more successful flights! It really is nice to have confidence in the turbine. The turbine is running as advertised. I haven't changed the fuel system yet...will do so before flying again. I wanted to ensure the flameout problem was solved first.

Cheers,
Keith

(in reply to speedbrake)
       Post #: 36

RE: PST contact? - 8/27/2006 6:20:03 PM   
speedbrake


 

Posts: 188
Joined: 1/22/2006
From: Fort Valley, GA, USA
Status: offline 		Kelly,
Another jet flyer experienced a FOD incident at our field. We got to taking about using FOD screens. Do you recommend the use of a screen on the PST? How much are they?

What is the average life span for a glow plug/PST600R?

Thanks,
Keith

(in reply to speedbrake)
       Post #: 37

RE: PST contact? - 8/31/2006 6:01:11 AM   
Kelly W



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Joined: 1/21/2002
From: Delta, BC, CANADA
Status: offline
quote:

ORIGINAL: speedbrake

Kelly,
Another jet flyer experienced a FOD incident at our field. We got to taking about using FOD screens. Do you recommend the use of a screen on the PST? How much are they?

What is the average life span for a glow plug/PST600R?

Thanks,
Keith



Keith, Sorry for taking a few days to reply. I just got back from a short trip down to Seattle where I finally saw the SR-71 for the 1st time at the Museum of Flight!

Go to your nearest dollar store and pick up a strainer that roughly matches (slightly smaller) the intake fairing on your motor. Remove the handle(s), cut a hole in it and insert a rubber stopper or equivalent, and you've got yourself a FOD screen on the cheap! It'll run you somewhere around $3... Either that or I can recommend a few sources that are pre-made but more expensive...

The glow pug life span differs greatly. I don't have any numbers here, but they can last a very long time if you treat them right. I have not changed the plugs in any of my engines for quite some time... Many factors can effect plug's lifetime: filament diameter, plug voltage, number of starts, average length of glow voltage applied per start cycle, how good you are at pulling out the fillamement with evenly stressed coils, etc...

To achieve best results anneal the plug before pulling out the coils. Do this with a glow ignition and pulse it to make the coil come back to room temp slowly. Next get a pin or pointy exactro knife blade and deflect the first rotation of the helix out. Follow that with next rotation and the 3rd if necessary, such that they are close to evenly stretched when the total exposure matches up with the 2mm spec in the manual (on page 10). The motor comes with an OS A3, but any plug without an idle bar should work... Personally, I try to run a plug voltage that's as low as possible. I started around 2.1V and went as low as 1.7, while still getting reliable ignition.

Kelly

< Message edited by Kelly W -- 8/31/2006 6:02:13 AM >

_____________________________

Kelly Williams, GTBA #1969

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       Post #: 38

RE: PST contact? - 8/31/2006 6:25:19 AM   
Molar mender


 

Posts: 564
Joined: 10/5/2002
From: Bonney Lake, WA, USA
Status: offline 		[/quote]

Go to your nearest dollar store and pick up a strainer that roughly matches (slightly smaller) the intake fairing on your motor. Remove the handle(s), cut a hole in it and insert a rubber stopper or equivalent, and you've got yourself a FOD screen on the cheap! It'll run you somewhere around $3... Either that or I can recommend a few sources that are pre-made but more expensive...

Kelly
[/quote]

Keith

Here is the system I use for my PST's. It is a 3" tea strainer that can be purchased at any store that sells dinnerware. Just cut off the handle and the two ears oppisite the handle and you have a ready made FOD screen. Carefully cut the hole in the middle to fit the starter and seal the screen with thick CA or grommet. Slide it over the starter and hold in place with an O-ring on the starter hub.

Roy

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< Message edited by Molar mender -- 8/31/2006 6:26:1