Go Back  RCU Forums > RC Airplanes > RC Jets > Turbine Clinic > PST Jets
 Few questions about PST engines >

Few questions about PST engines

Notices
PST Jets Direct support for PST Jets Turbines.

Few questions about PST engines

Old 12-23-2005, 12:40 AM
  #1  
Thread Starter
 
Ragz's Avatar
 
Join Date: Dec 2001
Location: Nagpur, INDIA
Posts: 2,612
Likes: 0
Received 7 Likes on 4 Posts
Default Few questions about PST engines

I recently saw a PST 1300 engine. Very impressive performance indeed. I have a few questions about the engine though.

1. What is the advantage of NOT having a fuel solenoid valve like other engines?
2. What is the advantage of having a FUSE inline with the TEMS ECU?
3. What is the advantage of having a switch between ECU battery and ECU?

I believe even the PST 600R has a similar setup. I am considering getting either of these engines and would like to understand the advantages of the current setup.
Old 12-23-2005, 04:09 AM
  #2  
My Feedback: (2)
 
Join Date: Jan 2002
Location: Delta, BC, CANADA
Posts: 1,015
Received 3 Likes on 3 Posts
Default RE: Few questions about PST engines

Hi Ragz, thanks for asking.

You're correct in that both engines come with the exact same setup, aside from a different model of pump and different software parameters.

1. Simplicity and Cost... I'll admit there is a potential for a hot-ish' start if someone forgets to close the ball valve while fuelling up, but typically this isn't a problem. I've only done it once and the flames were minimal. Pouring any residual out the back end should expel enough to avoid major damage to an internal setup. Performing a false start also helps to clear the motor. (false start = activating the start sequence without giving it butane / propane mix) Following that, you could initiate a proper start with the fuel valve close, burning of any excess that's still in the motor casing. I honestly don't hear many comments about it; none that I can recall in the last year for sure... I do make a habit of manually closing the ball valve as soon as the engine is shut down for that reason though, and I also teach the same habits in the ground schools I've done. As for shut down, the ECU simply cuts power to the pump with a stick-down and trim-down command.

2. Unlike some ECU's, the PST ECU is actually powered by the ECU pack and draws and extremely small amount of current from the RX pack. The 1st advantage of the fuse is when a customer makes up his own pack and accidentally reverses the polarity. Once plugged in and switched on, the fuse will blow and likely save the system from a great deal of damage. I've seen some ECU's saved by the fuse, and yet some are cooked just before the fuse blows. Its not a be-all end-all fix, but it does help. The other main reason is in the event of a short, the ECU will also likely be saved. Such shorts could be modified cables, a seized starter motor, seized pump, or a glow plug harness that's damaged and shorted directly to the plug base. Simply put, there's always a potential for something unforeseen to go wrong, which is why you have so many fuses in your car's fuse box. Putting a fuse in the ECU power cable is just common sense basically, and the additional cost incurred in the fuse and fuse holder is cheap insurance.

3. As stated in #2, the ECU is powered by the ECU pack, and not the RX pack. For this reason, we include a switch to allow the ECU to be shut down without disconnecting the ECU battery. If someone were to get creative (although this would void the warrantee) they could theoretically solder a +ve charge receptacle onto the other set of poles in the switch and splice a charge lead into the system... That's not an officially supported modification from PST, just something I've been meaning to try one of these days. I run Duralites, which already have their own charge post, but next time I run a system on a Ni-Cad or Ni-Mh pack, I'll try it. I don't know that there's much of an advantage to not drawing a current off the RX system to power the ECU, but with the current requirements of several digital servos every bit helps.

I hope that answers all your questions.
Kelly


ORIGINAL: Ragz

I recently saw a PST 1300 engine. Very impressive performance indeed. I have a few questions about the engine though.

1. What is the advantage of NOT having a fuel solenoid valve like other engines?
2. What is the advantage of having a FUSE inline with the TEMS ECU?
3. What is the advantage of having a switch between ECU battery and ECU?

I believe even the PST 600R has a similar setup. I am considering getting either of these engines and would like to understand the advantages of the current setup.
Old 12-23-2005, 04:33 AM
  #3  
Senior Member
 
Join Date: Jul 2002
Location: Bangkok, THAILAND
Posts: 726
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Few questions about PST engines

Hi,

I see that Kelly beats me for the answers. Lets just consider the following info as an additional input to Kelly's answers.

ORIGINAL: Ragz

I recently saw a PST 1300 engine. Very impressive performance indeed. Thank you. I have a few questions about the engine though. Answers in Blue.

1. What is the advantage of NOT having a fuel solenoid valve like other engines?
Fuel solenoid valve is closed when there is no power thus blocking fuel to the engine (Failed closed). The advantage here is that you can avoid a flooded engine if you forget to close the manual valve during refueling. Disadvantages: First scenario, while operating and the fuel solenoid valve fails, the fuel valve will close thus causing a shutdown even though the ecu and the turbine are in good health. Second scenario, shuting down and the valve stuck in open position causing a turbine run-away condition. TEMS ecu, on the otherhand, will cut power supply to the fuel pump for shutdown command. So, the advantage here is that you will get a shutdown only from a Tx command or lost of R/C signal or over parameters conditions or shutting off the manual valve. If you just don't forget to turn the manual valve off after shutdown or before fueling, then the advantages are as stated. BTW, for safety, you will need manual shutoff valve anyway whether you are using fuel solenoid valve or not.

2. What is the advantage of having a FUSE inline with the TEMS ECU?
To protect the TEMS in case you plug in an inappropriate power supply

3. What is the advantage of having a switch between ECU battery and ECU?
So you can switch the TEMS on/off without having to pull the power plug. Similar to turning on/off your radio system.

I believe even the PST 600R has a similar setup. I am considering getting either of these engines and would like to understand the advantages of the current setup. Please do not hesitate to contact us for any information. Thank you.
Best regards,
Kraivuth S.

Old 12-23-2005, 07:52 AM
  #4  
Thread Starter
 
Ragz's Avatar
 
Join Date: Dec 2001
Location: Nagpur, INDIA
Posts: 2,612
Likes: 0
Received 7 Likes on 4 Posts
Default RE: Few questions about PST engines

Thanks for the detailed reply. I can understand the fuel system. But arent we adding more links in the chain that can go bad? What if the fuse blows in air? What if the switch shorts in air? Why dont other manufacturers use this method of powering and running their engines? These questions are purely out of curiosity no other intention.
Old 12-23-2005, 11:01 AM
  #5  
Senior Member
 
Join Date: Jul 2002
Location: Bangkok, THAILAND
Posts: 726
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Few questions about PST engines

If we are going to look at all possibilities of things that can go wrong then the list is endless.

Let's be logical. If the switch is shorted or the fuse gets blown during flight then there are reasons for such malfunction that would have commanded any ECUs to shut the turbine down anyway (if the ecu survived). The switch can be omitted and bypassed but the fuse is there to protect the TEMS. You may not see fuses or switches on some turbines but there must be some sort of built-in protection and power isolation circuitry that may not be as obvious as ours. Only when it comes to repair that you would see the differences.

Anyway, in the past 3 years, we have not seen a shorted switch or blown fuse during normal operation yet.

Hope that we can be at your service very soon.

Kraivuth S. B777


Old 12-23-2005, 12:24 PM
  #6  
My Feedback: (1)
 
Join Date: Feb 2002
Location: private, UNITED KINGDOM
Posts: 3,672
Likes: 0
Received 26 Likes on 16 Posts
Default RE: Few questions about PST engines

ORIGINAL: Kelly W
I honestly don't hear many comments about it; none that I can recall in the last year for sure...
I posted the question just 1 month ago which you answered! see my post of 21 Nov.
However I see B777's point about it being a problem if it failed in flight and closed off the fuel, I don't think my Sabre will make a good glider.

H
Old 12-23-2005, 12:44 PM
  #7  
My Feedback: (2)
 
Join Date: Jan 2002
Location: Delta, BC, CANADA
Posts: 1,015
Received 3 Likes on 3 Posts
Default RE: Few questions about PST engines


ORIGINAL: HarryC

ORIGINAL: Kelly W
I honestly don't hear many comments about it; none that I can recall in the last year for sure...
I posted the question just 1 month ago which you answered! see my post of 21 Nov.
However I see B777's point about it being a problem if it failed in flight and closed off the fuel, I don't think my Sabre will make a good glider.

H
Harry!
You got me man... This is exactly why I shouldn't reply to postings at 2AM while I've got a nasty head cold and can't sleep...

I was just referring to cases where I was chatting with guys at the strip, one the phone, etc. My bad... Anyway, the point I was trying to make is that its not really a big problem according to what I hear from customers. That being said... To offer the option, I hope GB includes this function if they decide to revise the design.

Kelly
Old 07-23-2007, 10:16 AM
  #8  
 
speedbrake's Avatar
 
Join Date: Jan 2006
Location: Fort Valley, GA
Posts: 476
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Few questions about PST engines

Kelly,
I have a couple of questions about my PSTs. First, I just unpacked a new PST600R and noticed the Ground Display Unit has a rattle. Something inside the box is loose. Is it alright for me to open the box without adversely affecting the warrantly?

Second, my other PST has been difficult to start. The propane is not flowing into the tank....almost as if a tube is bent or plugged. It has been necessary to inject propane during the ramp up to get past 17,000 RPM during start. I've changed the propane bottle so can rule that out. I haven't changed the tubing yet but that will be my next move. After the initial attempt to inject propane, the second attempt seems to work. The turbine runs normally other than the propane problem.

Chow,
Keith Lindsay
Old 07-23-2007, 01:06 PM
  #9  
My Feedback: (2)
 
Join Date: Jan 2002
Location: Delta, BC, CANADA
Posts: 1,015
Received 3 Likes on 3 Posts
Default RE: Few questions about PST engines

Hi Keith,

In this case I think I'll ask them to make an exception if you feel comfortable doing it. (Do not take this as a blanket statement that users can do this an not adversely affect warranty)

The box is relatively easy to open. There are 4 Phillips screws hidden under the rubber feet. Scrape the feet off with a slot screw driver. Don't get the adhesive dirty as you'll be re using them. Undo the screws, then take an exacto knife and gently pick one of the back plate sides away from the case. It may be tight... open it up slightly (not much, to avoid pulling the cables) and see if you can shake the offending item out. Please let me know what you find... I assume the unit still functions correctly?


On the start gas issue... You may have a kink in the line, or some other restriction, or not. Hard for me to help here without the jet in front of me... It could also be an EGT probe depth issue though. If you have adequate gas flow, but your probe's out of position, the EGT may take its time and you may run low on vapour pressure in the on-board tank. Running temps will also look low if this is the problem. You'll probably find this isn't a problem if you eliminate the on-board canister and run from an separate external source. Reason being, the external tank has a lot more vapour build up and will take much longer before you get a drop in pressure.

Kelly
Old 07-23-2007, 06:11 PM
  #10  
 
speedbrake's Avatar
 
Join Date: Jan 2006
Location: Fort Valley, GA
Posts: 476
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Few questions about PST engines

Kelly,
Inside the ground display unit are two circuit boards. Both boards have two screws holding them in place. The larger board has fours holes, one in each corner. However, the two blank holes, no screws, don't seem to be tapped. The rattle I heard was an extra board mounting screw. Since the GDU hasn't been used yet it is probably OK....no short likely. I'll let you know if there is a problem.

I'll keep you posted on the propane filling problem.

Chow,
Keith
Old 07-25-2007, 03:35 PM
  #11  
 
speedbrake's Avatar
 
Join Date: Jan 2006
Location: Fort Valley, GA
Posts: 476
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Few questions about PST engines

Kelly,
I found fluid in the on-board propane tank. Not sure what it means....the pressure should have been exhausted during the last start. I don't turn the propane supply tank upside down when filling. Could it be a residual from previous start sequences? I have eightly flights thus far. I remember the trouble started when the glow plug started going bad. I went through four or five start sequences before realizing the plug was faulty. Do you think there is any correlation between the two? Other wise the turbine has been running normally. It has always been slow to ramp up so this problem wasn't readily apparent at first.

Keith
Old 07-29-2007, 09:06 AM
  #12  
 
speedbrake's Avatar
 
Join Date: Jan 2006
Location: Fort Valley, GA
Posts: 476
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Few questions about PST engines

Kelly,
I removed the on-board propane canister and drained what fluid was inside. After reassembly, the system worked perfectly. The system takes a full charge each start and the ramp sequence is back to normal. Not sure what the issue was but can't beat success.

I have eighty flights on my plane and turbine. I guess it is time to find out what is required for returning the turbine for overhaul. Please let me know the address and what is needed to be returned. Any idea of cost? I've never read about the cost of rebuilt...strange you've thought somebody would have mentioned it before.

Thanks,
Keith
Old 07-30-2007, 12:31 AM
  #13  
My Feedback: (2)
 
Join Date: Jan 2002
Location: Delta, BC, CANADA
Posts: 1,015
Received 3 Likes on 3 Posts
Default RE: Few questions about PST engines

Hey Keith,
I gotta keep this short as I'm out of town at the High River Jet Rally. Back in contact ~Aug 7. (BTW everyone else, if you call my place for customer support, I'm not there and the guy staying there won't know anything about turbines!) Please email / PM me in the mean time...

Fluid left over in the canister is normal. It likley won't all be consumed in the previous start.

The burn time on propane is driven by many, many factors. If it takes time getting up to 110C, you'll have a longer start. Once on kero, its a function of the start ramp setting.

I'll put you in contact with the service dept when I return. Either that or you can just contact 'B777' on RCU (Kraivuth in Thailand).
Old 08-01-2007, 02:31 PM
  #14  
 
speedbrake's Avatar
 
Join Date: Jan 2006
Location: Fort Valley, GA
Posts: 476
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Few questions about PST engines

B777,
I just obtained a second PST600R. There is a lead coming from ECU I'm not sure what it is. It is a black two wire lead with a male two pin plug. On the plug is red heat shrink material and the letter "F" labeled on it. I assume it is a lead for the (new) fuel solenoid. I have all the other leads coming from the ECU hooked up. My other (older) turbine ECU does not have a similar lead.

Thanks,
Keith
Old 08-01-2007, 11:11 PM
  #15  
My Feedback: (2)
 
Join Date: Jan 2002
Location: Delta, BC, CANADA
Posts: 1,015
Received 3 Likes on 3 Posts
Default RE: Few questions about PST engines

Hey Keith,

Just popped in for an RCU fix while on the road.

You’re correct, the black lead with the red heat shrink is the new (optional) fuel solenoid control plug.

As a side note, anyone in North America interested in getting the upgrade to an older ECU can contact me directly. I have all the hardware to perform the upgrade out of Vancouver. It involves adding a new solenoid driver board, and software update if the ECU has software prior to V2.38 for 600R’s and 3.38 for 1300R’s. I need the ECU and data terminal to perform the upgrade. If the software needs to be updated, the ECU will return with the most recent version 2.39 / 3.39.

Kelly
Old 08-02-2007, 12:42 AM
  #16  
 
speedbrake's Avatar
 
Join Date: Jan 2006
Location: Fort Valley, GA
Posts: 476
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Few questions about PST engines

Kelly,
Does that mean my ECU and software have been upgraded and I only need to purchase the solenoid/valve? If that is correct I would be interested in buying the valve.

Keith
Old 08-02-2007, 08:37 AM
  #17  
Senior Member
 
Join Date: Jul 2002
Location: Bangkok, THAILAND
Posts: 726
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Few questions about PST engines

Hi,

Any high volume 6v fuel solenoid valve should work fine. However, we are recommending the JetTronic fuel solenoid valve.

Regards,
Kraivuth S.
Old 08-19-2007, 08:12 PM
  #18  
 
speedbrake's Avatar
 
Join Date: Jan 2006
Location: Fort Valley, GA
Posts: 476
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Few questions about PST engines

Kelly,
Took a look at the number of starts the ECU has in its memory. I was surprised at the number...much higher than what my log indicates. My question to you is "what constitutes a start?" I thought once the start sequence gets to "idle set" that constituted a start. Now I'm not so sure.

Need to chat with you away from this forum...please provide me with an email address.

Thanks,
Keith
Old 08-20-2007, 03:25 AM
  #19  
My Feedback: (1)
 
Join Date: Feb 2002
Location: private, UNITED KINGDOM
Posts: 3,672
Likes: 0
Received 26 Likes on 16 Posts
Default RE: Few questions about PST engines

I would like to know too. Mine seems to count a start if it sends the signal to the fuel pump to run, even if the pump isn't working etc and the fuel never gets going. My ecu has counted far more starts than the number of genuine engine runs

Are the PST 600 fod guards available yet?

Harry
Old 08-20-2007, 08:24 AM
  #20  
 
speedbrake's Avatar
 
Join Date: Jan 2006
Location: Fort Valley, GA
Posts: 476
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Few questions about PST engines

Harry,
The P60/70 guard fits perfectly. I've seen one installed on a PST. They are a good quality item.

Keith
Old 08-20-2007, 10:30 AM
  #21  
My Feedback: (2)
 
Join Date: Jan 2002
Location: Delta, BC, CANADA
Posts: 1,015
Received 3 Likes on 3 Posts
Default RE: Few questions about PST engines

Hi Keith and Harry,

The start count looks for a specific event before it increments the start count, zeros the previous run's glitch count, etc. I believe that event is voltage being applied to the pump, meaning the engine has sustained the minimum RPM and EGT for a start and its time to ramp on Kerosene. You've raised an interesting idea about perhaps setting the trigger as the completion of idle set or something further down the road. I'll enquire about it.

The FOD guards, I've heard nothing about them from PST lately. I'm not part of PST's sales arm, mainly service and spare parts, so perhaps Kraivuth (B777) can get you a more accurate answer.

I don't post my email address directly in the forum any longer, since it always results in a new boat load of spam... Please see this [link=http://www.pstna.com/service.htm]link[/link] for the PTNA service page, which has my contact info listed.

Kelly
Old 09-11-2007, 10:51 AM
  #22  
 
speedbrake's Avatar
 
Join Date: Jan 2006
Location: Fort Valley, GA
Posts: 476
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Few questions about PST engines

Kelly,
Just wondered if you received an answer about what constitutes a start? I would like to see the trigger be "idle set", assuming I have a vote in this.

Keith
Old 09-12-2007, 01:16 AM
  #23  
My Feedback: (2)
 
Join Date: Jan 2002
Location: Delta, BC, CANADA
Posts: 1,015
Received 3 Likes on 3 Posts
Default RE: Few questions about PST engines

Hey Keith,
Sorry, no progress to date.

Last time I sent GB and email the address wasn't working. I think they've just got some server issues at the moment.

I'll recommend that they look into it for the next software version, but I don't think they have any new releases planned any time in the immediate future. I don't write the software, so I can't really give any more information than that unfortunately...

Kelly

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are On


Thread Tools
Search this Thread

Contact Us - Manage Preferences Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.