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-   -   New member, lots of questions!!! JPX turbine (https://www.rcuniverse.com/forum/rc-jets-120/11600094-new-member-lots-questions-jpx-turbine.html)

Justflying1 06-11-2014 01:16 AM

Yeh nice one. Is this how you are going to build your posts.
Yes the gentleman unfortunately did not research before purchase, but maybe he is not as rich as you and possibly got the turbine at a reasonable price in the hope to break into the jet community.

erbroens 06-11-2014 04:55 AM


Originally Posted by xjsftsdghu (Post 11821517)
Jeez. I've never seen a turbine with an oil port.

http://finanziellede.de/hu6l.jpg

Full size jet turbines have a closed cycle lubrification system .They have a oil port too.

The JPX and Turbomin had a pressurized oil port, in wich the oil is directed to the bearings by the "cold" air pressure taken from the turbine case. After lubricating the bearings the excess oil is burnt away with the turbine hot gases,

This system is not bad, as modern turbines with its mixed oil / fuel solution burn most of it expensive synthetic oil without lubrificating anything. This system only takes more space in the airframe and needs extra attention and maintenance for working properly.

ravill 06-11-2014 07:32 AM

More power to the OP!

If he wants a project turbine, great!

I've only played with one airstart engine and it was certainly a novelty for me.

yeahbaby 06-11-2014 07:39 AM

LoL long live the iron lungs!!!!.

thedeerhunter 06-11-2014 11:30 AM

any suggestions for glow plugs? should I get the hottest I can find? will the reach into the combustion chamber be long enough? the original plug looked like it extended about an inch in the chamber. I have no idea what that plug was, no info stamped on the insulator and I can't find anything that looks even close online, weird.

erbroens 06-11-2014 11:42 AM

Any glowplug will work.. it only needs to glow well, almost white-orange to ignite the gas. This is more a voltage factor than anything else. about 2 volts will do the trick. You also must not have it lighted on for long, or it will burn.

If you do the glow conversion, you should machine a adaptor that will expose the glowplug filament well into the gas flow in the combustion chamber.

Instructor 06-11-2014 01:40 PM

Hi thedeerhunter,

I flew a Kangaroo with a JPX T-250 for one year. Most of the replies you have received already are telling you not to fly with this turbine. Since you already mentioned that you don't plan on trying to fly with it, here is what I remember on the starting of this turbine. The glow plug you call it is an igniter
like the one used in a propane gas grill.

First hook up the air to the small tube on the side of the inlet. Attach the Ignition to the sparkplug and then ground it to the turbine. I like to use the small propane tube coming from the exhaust outlet to the GRU ( Gas Regulation Unit). Hook up the gauge to the right side port of the engine. This is a millibar gauge. You will need a t fitting in the clear line going to the oil tank. This can be medium glow fuel line. Attach the gauge to this line. Be sure to pinch off the line to the compressor and blow air into the oil tank filled with turbine oil until you see oil going into the turbine on top of the turbine. The turbine is now ready to start.

The air pressure should be around 150psi coming out of the regulator. When you spool it up, you will hear two different sounds. One is a low pitch and the other is a high pitch. When the high pitch is achieved, then the Ignition button is pressed. Open the propane valve about 1/4 turn or until you hear ignition. Open the fuel valve all the way open. Move the throttle rod out on the GRU until the millibar gauge reads 0.60 bar. If the gauge doesn't read 0.60, then the GRU will have to be adjusted until it reads 0.60. You might have to screw the GRU in or out until you reach this reading. At this time, you can disconnect the air, Ignition. Move the throttle rod out all the way. Adjust the GRU until the gauge reads 1.2 BAR.

The turbine is now running full throttle. To get low throttle, push the throttle rod in until the gauge reads 0.02 to 0.04. To shut down the turbine, pull the throttle rod out until the gauge reads 0.40 bar for about 6 seconds, then turn off the propane. Use a leaf blower to cool down the turbine. Good luck.....

Larry/ Instructor

Kevin_W 06-11-2014 01:46 PM

If all else fails you can always light it off by hand.
A butane fireplace lighter (the type with the long extension) placed near the exhaust will usually do the trick. The gas in the exhaust will ignite and the flame will move forward into the combustion chamber quickly as it hunts for the proper fuel/air mixture.
[Disclaimer: This method can be rather dangerous if you use too much gas (especially in enclosed spaced), or are not quick enough getting the rpm's up once it lights]
I started my FD3-67 this way a few times. It works fine as long as you pay close attention to gas flow and starting air.

JackD 06-11-2014 02:07 PM

Man, things have gotten a lot easier!!!!

Instructor 06-11-2014 02:22 PM


Originally Posted by JackD (Post 11821988)
Man, things have gotten a lot easier!!!!

Yes Jack they have, but that was the way it was done in 1994. Also at that time, you had to go to ground school to learn how to start a manual turbine. When the kero burners came out, you also had to go to ground school to learn how to start them. They showed you how to start them and also what to do if there was ever a problem. Today the full kero start turbine can have a hot start and continue to feed kero to the turbine. With the manual start turbines, the pilot or the helper knew how to instantly shut it down to pervent fire damage to the aircraft. The air start turbines were spooled up a few times to get any propane fumes out of the combustor chamber before the ignition was appilied......

Laarry / Instructor

Larry/ Instructor

LGM Graphix 06-11-2014 02:24 PM

I stlil love my air start AMT, makes me feel like I'm part of the process!!!

JackD 06-11-2014 02:28 PM


Originally Posted by Instructor (Post 11821995)
Yes Jack they have, but that was the way it was done in 1994. Also at that time, you had to go to ground school to learn how to start a manual turbine. When the kero burners came out, you also had to go to ground school to learn how to start them. They showed you how to start them and also what to do if there was ever a problem. Today the full kero start turbine can have a hot start and continue to feed kero to the turbine. With the manual start turbines, the pilot or the helper knew how to instantly shut it down to pervent fire damage to the aircraft. The air start turbines were spooled up a few times to get any propane fumes out of the combustor chamber before the ignition was appilied......

Laarry / Instructor

Larry/ Instructor

I know.. that was our first turbine (t260) back in 95. I still have a classic bandit my dad built in 97 with JPX stickers all over it!!!

Starting it was more fun than flying!!!

mr_matt 06-11-2014 04:44 PM


Originally Posted by Instructor (Post 11821995)
When the kero burners came out, you also had to go to ground school to learn how to start them. They showed you how to start them and also what to do if there was ever a problem. .....

you tell em Larry. I remember I had a special waiver for the Golden West, the Hammer (the original JetCat name), and AMT Peguses and the AMT Mercury. Had to get a cert for every motor.

Also, at the time each turbine had to be AMA certified, during which it had to be tested to destruction. This was a real barrier to entry in the US market (for anyone who cared about having an AMA sanction, I should say). Bob Wilcox led the charge to get that AMA barrier removed (he could have pushed to keep it in place to help JetCat but he knew that AMA had no business doing this).

ravill 06-12-2014 11:17 AM

OMG, no thanks!

I love auto-start!!

I can understand the desire to want to do an airstart every once and a while for S & G's, but for flying ease, nothing beats the miracle of auto-start!

Kevin_W 06-12-2014 12:56 PM


Originally Posted by ravill (Post 11822553)
OMG, no thanks!

I love auto-start!!

I can understand the desire to want to do an airstart every once and a while for S & G's, but for flying ease, nothing beats the miracle of auto-start!

Auto start may be simple and easy, but I know I felt a lot more in control when starting my FD3-67, and in most cases I could whisk through the entire process and have the turbine up and running in less than 30 seconds. It was a heck of a lot quicker and easier than starting a OS-91. LOL

erbroens 06-12-2014 01:44 PM


Originally Posted by Kevin_W (Post 11822610)
Auto start may be simple and easy, but I know I felt a lot more in control when starting my FD3-67, and in most cases I could whisk through the entire process and have the turbine up and running in less than 30 seconds. It was a heck of a lot quicker and easier than starting a OS-91. LOL

No way! is impossible to not start a O.S. engine in the first flip unless you have a dead glow starter! :)

ravill 06-12-2014 02:18 PM

Ah, the OS 91! What a great little engine!

c/f 01-01-2016 10:21 AM

We have a club member who works for his brother inlaw here..., http://www.lantzscoachworks.com/ , back in the 90's he had a F4 built by Lewis Patton with two JPX in it, it currently sits as a hangar queen, and since I am the only turbine pilot around this area , he had seen my at a flyin few years back and started talking about getting this thing airborne with me, when I looked into twin JPX, I said out of my league, buy some modern day turbines and I would be glad to help out, He never called back. So here is another JPX sighting nationwide I thought relevant to document. Lewis knows all about it as well as me as he did my AMT/Waiver sign off back in 2000. I think I recall that that two turbines were not separated in own chambers which would also be fun with propane gas run turbines.......02

Countryboy 01-01-2016 03:24 PM

I think I have some old photos of that F-4.... at least cockpit photos. Photos were taken at Superman many years ago. To my knowledge, the jet was never flown.

Sorry to hear of the recent passing of your friend John Mathis. Very nice guy... I had actually been to his home years ago.

jetmaven 01-01-2016 03:43 PM

Let's give Bob Fiorenze some credit here , he managed to stuff one of these in a
Yellow F-16 and flew perfectly in front of a mesmerized crowd at one of the very first
Floida International Jet Rally's back in the early -mid 90's .

c/f 01-02-2016 08:45 PM

Thanks Country Boy jack was a great guy, I have to stand corrected on my recent post on the F4, We has our chili Flyin today and was discussing the F4 and it has turbomin turbines in the F4, It still has never flown..............


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