duncan
Junior Member
Joined: December 2014
Posts: 68 
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Post by duncan on Jan 1, 2015 15:18:43 GMT -5
Hello everyone & greeting from Indy! I joined JATO just about a week ago after finding it via Google, while searching for info regarding the Fairchild J44 turbojet engine. I bought one (a J44-R-24 from 1954) in November of 2013 & just got it running almost exactly a year later, this November. I am doing this as a hobby & possible 'retirement project', and because boys never really grow up, only their toys do! I enjoy electronics & mechanical stuff, so jet engines go right down my line.
I started on JATO reading a thread called "New member here with a J44...", which was started by member 'dond', where I posted a few pix & gave links to my photo album, "The J44 Project" on Photobucket. I am listing them here too, so you can see almost every step from picking it up to the 3rd run! I do not have any still camera shots of the first start attempts nor the first & second runs; I do have video & plan to upload them to You Tube once I buy a new computer & edit them. I hope to help others in the gas turbine engine world as well as learn from you as well! Speaking of You Tube, check out "Back Yard Jet", parts 1 & 2, as well as the over 300 videos on jet engines from 'Agent Jay-Z', a jet tech in Canada! He has spent a lot of time sharing his experiences with us, including lots of test cell time, as well as theory & practices. Recommended here!
Cheers!
Darren Duncan
"The J44 Project" album links: s1058.photobucket.com/user/Darren_Duncan/slideshow/The%20Fairchild%20J-44%20Project
s1058.photobucket.com/user/Darren_Duncan/The%20Fairchild%20J-44%20Project/story
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duncan
Junior Member
Joined: December 2014
Posts: 68
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Post by duncan on Jan 1, 2015 15:20:46 GMT -5
SUMMARY <So Far>:
Since I have no prior experience with gas turbine engines & the J44 in particular, this project has been one of reading, trial & error, failures & successes! I have a nice copy of the USAF manual covering the J44-R-3, and I also have one of those old orange tech school manuals I got from Essco Aircraft (On Ebay), which covers the J44-R-24, which is my model. According to the manuals, the R-3 uses a more sophisticated fuel control system while the R-24 uses a simpler design. My R-24 is 'in between' that shown in the 'orange' manual & the R-3. My engine has an 'Acceleration Limiter Valve Assembly' in line between the governor fuel control outlet & the fuel cutoff valve. The R-3 also has a limiter valve, along with the servo control fuel system. Its purpose is to limit overtemping & compressor stall due to too much fuel at once. It measures compressor inlet, outlet, & fuel pressures then adjusts the maximum fuel flow to safe limits.
Overall, my main concern was the fuel control system & its operation. The previous owner said, "It runs." & I did find the filter container & lines to be clean, with no gunk or worse yet, corrosion! I wasn't sure if it would even start & then if it wouldn't just speed up out of control. Well, it starts & accelerates right up to idle at about 31-32% RPM so that part seems OK.
The next concern was that the lube system is/is not working. I ensured that the lines were clear & even pressurized the system with compressed air (less than 30 PSI!), which produced the 'oil mist'. After that test, I had excess oil running out of both bearings. I checked the front frame & inside of the jet pipe, at the rear bearing support, for oil puddling/running, after each run. This indicates the system is working & supplying oil! Looks good here.
Starting her was the next challenge. I tried with straight K-1 but got no light-off; just fuel spraying & blowing out of the exhaust. After 2 tries like this, I contacted the previous owner, who has had several of these engines. He said "These J44s are hard to start & generally won't, using just K-1 or even Jet A. You need to add some gasoline to the mix! About 20-30%. That should do it." Well, I mixed about 2.5 gallons of gas into my 8 gallons of K-1 already in the fuel cell, then purged the fuel system up to the fuel manifold. That did the trick! It lit-off with a 'Poof'! I killed it a couple of seconds later due to the fact that I didn't have any help with spotting & fire extinguisher manning. A second start try fired right off also, so I felt it was ready for a test run.
With a couple of friends to assist me, we rolled it out into my driveway on another day & made the first full start & run! It quickly came up to idle, with my hand nervously on that Emergency stop button, then stabilized at about 31% RPM. What a rush! You can 'feel' that power there, albeit a small & old school engine. With a fuel consumption rate of 1.65 lb./hr./lb. thrust, it IS NOT an economical engine to run! Yes it does drink some fuel! About 0.75 gallons per minute at idle! My 15 gallon fuel cell should run about 20 minutes at that setting & only about 3 - 4 minutes at full power! The used fuel boost pump I bought on eBay will not flow enough to run the engine above 50% RPM, which is fine for a start. I will replace the pump (28 V, mounted on the stand down next to the fuel cell) when other bugs are worked out & I can afford it. I get 25 PSI with the fuel cutoff valve closed & it drops to about 15-20 lbs with the engine at idle. Accelerating to 40% causes a drop to less that 10 pounds, so not much left.
On the first run, upon observing the tail pipe view of the engine, I discovered some erosion of the turbine nozzle blades around the '8 to 10 o'clock position', where I could see fire visible through it. Upon closer examination using a flashlight on a cool engine, I can see the some deterioration of several of the nozzle (stator) blades. This will require removal of the rear end & turbine wheel, to access the nozzle assembly. I am hoping my buddy can weld it up because these aren't around anymore! I don't think it is safe to run it up over idle with this damage; actually it really should not be ran at all! There is a chance that a blade could break-off & damage the turbine rotor! This would be a good time to have the turbine inspected for cracks or other signs of stress, as well as replace the rear bearing if needed. I will try to get this done before Spring, God willing.
In conclusion, I have taken almost a year since buying the engine in November of 2013, to get it running. That was a great feeling of accomplishment to reach that point! Half of the 'fun' is just the engineering, building, wiring, plumbing, troubleshooting, changing & getting it to run! Running it & sharing that experience with friends is the other half. I could have just patched it together some simple switches & wires but I wanted to make a cleaner look, so I just spent more money & bought some nice hardware! I have to buy a new computer so I can edit & process my videos! This old system (from 2006, Windows XP) just chokes on these HD video files! I will upload them to You Tube as soon as I can. I hope my experience can benefit some of you out there in gas turbine engine/J44 world! Also, I hope to learn more about them from you as well. Take Care & Cheers!
Darren Duncan
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duncan
Junior Member
Joined: December 2014
Posts: 68
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Post by duncan on Jan 1, 2015 15:28:07 GMT -5
Since this project has been around so long, I will have to repost the photos once hosted by "Photo Bucket".
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Post by ernie wrenn on Jan 2, 2015 9:43:41 GMT -5
Good looking engine.. What size is the exhaust tube?
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Post by ernie wrenn on Jan 2, 2015 9:59:09 GMT -5
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Post by finiteparts on Jan 3, 2015 19:22:02 GMT -5
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Post by finiteparts on Jan 3, 2015 19:24:10 GMT -5
By the way, does your engine have the thermocouples for monitoring the bearing temperatures? I didn't see the leads for them showing on the pictures.
~ Chris
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duncan
Junior Member
Joined: December 2014
Posts: 68
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Post by duncan on Jan 9, 2015 17:07:31 GMT -5
Good looking engine.. What size is the exhaust tube? Hi. this is the 'stock' <factory> jet pipe, which is 13 inches in diameter at the outlet & it is about 16 inches from the mounting flange to the outlet. Yes, the engine is clean; some rusty bolts & pipe plugs & an oxidized front frame/compressor housing from it sitting outside at some point in its past. I plan to replace the rusty stuff as I can, just for appearance. Thanks. DD |
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duncan
Junior Member
Joined: December 2014
Posts: 68
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Post by duncan on Jan 9, 2015 17:10:57 GMT -5
Thanks Chris! I will check those sources out... too cold here to do much outside! I even hate to heat my shop to work on the J44! Good time to research & read! Get 'em running! These antiques need love too! DD |
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duncan
Junior Member
Joined: December 2014
Posts: 68
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Post by duncan on Jan 9, 2015 17:17:12 GMT -5
By the way, does your engine have the thermocouples for monitoring the bearing temperatures? I didn't see the leads for them showing on the pictures. ~ Chris Chris, it has a rear bearing thermocouple, with the leads cut off at about 4 inches. It is curled-up around the oil & air tubing, near where they connect to the rear frame, at about the 3 o'clock position, facing the rear of the engine. There is no front thermo, that I can see. No leads anywhere. DD |
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duncan
Junior Member
Joined: December 2014
Posts: 68
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Post by duncan on Jan 9, 2015 18:25:16 GMT -5
Hey all, I have added a few pix to the 'J44 Project' album. They are of the new fuel drain line, from the fuel cutoff valve to the fuel cell & the removal of the 45 degree fitting that was on the boost pump inlet. The drain line allows excess fuel left in the manifold, line & cutoff valve to drain back to the tank when the engine is stopped. When the valve is de-energized, a spring slams the valve to the "OFF" position, which cuts the high pressure side off & also connects the outlet port (feeds to the fuel manifold & nozzles) to the drain port, allowing most of the fuel to immediately drain out. Without this drain, the fuel drains into the combustion chamber, keeping a fire going after the engine stops! Also, some excess fuel already in the chamber makes a hotter, 'fireyer' start, which ain't good either. If any fire is still burning inside the engine or tail pipe after a shut-down, the engine must be motored via the starter until it is out. The change in the fuel line from the tank to the pump inlet was just a matter of rethinking the installation. Why did I ever put that 45 on the pump inlet in the first place? Thought it was necessary at the time but I never liked it. I removed the fuel cell to install the new VDO fuel level transducer/sending unit, to work with my VDO fuel gauge on the console. It will give me some idea of how is in the tank & about how many seconds I have left! It is a 0 - 90 Ohm resistance unit with a simple float & it fits a wide range of tank depths. Upon reinstalling the tank onto the stand, I was able to remove the 45 fitting & just run it straight off of the pump. Looks much better. A couple of other changes are: Connecting the hour <time> meter to the "Fuel Valve" switch, so that it only runs (keeps time) when the fuel cutoff valve is "OPEN", as in when it is running & installing a large ('Max') fuse holder & 60 Amp fuse inside of the stand electrical box, to protect the charging circuit & connector (jack) on the side of the box. It is connected directly to the batteries, at the starter relay & common (-) ground terminals. A short at the connector or in the charger cord could result in a fire & damage, so installing a fuse will protect the wiring. The hour meter originally was connected so that it was on whenever system power was on... not a very good approximation of running time! Whenever the fuel valve is open (energized), the engine is running (or should be!), for the most part; this will help keep track of time on the engine. DD   |
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duncan
Junior Member
Joined: December 2014
Posts: 68
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Post by duncan on Jan 9, 2015 18:33:25 GMT -5
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izzy59
New Member
Joined: August 2015
Posts: 1
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Post by izzy59 on Aug 23, 2015 19:46:25 GMT -5
Any problems with battery overheating on multiple start attempts or is this a non issue?
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duncan
Junior Member
Joined: December 2014
Posts: 68
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Post by duncan on Nov 8, 2015 1:36:02 GMT -5
Hello; no, none noted so far. Batteries are Interstate AGM 1000 CCA Marine 'combo' start & deep cycle. Starter is only ran for 20-30 seconds then killed. If I do 2 runs, they will be around 20-30 minutes apart, giving time for the batteries & starter to cool.
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duncan
Junior Member
Joined: December 2014
Posts: 68
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Post by duncan on Nov 8, 2015 1:54:04 GMT -5
Hello all out in turbine land. I have uploaded a couple of new videos regarding the J-44 Project. One is an overview of the 'system', including the engine, accessories, peripherals, the stand & control console. The other deals with the turbine nozzle damage that has been growing and is now to the point of red-tagging the engine until it can be fixed. This will be a Winter project, which I plan to video parts of, to share later. I know these parts aren't available so I am hoping for a repair via a the same guy the fabricated the stand. It may not be possible but something needs to be done, else the engine will destroy itself or become a nice sculpture! I have ran the engine about 6 times this year, since the uploading of "Runs 3 & 4", noticing increasing erosion in the same area (3 airfoils), while the rest of the nozzle looks OK. My be due to a hot streak from the annular combustor, in that location, which I will look into after removing the nozzle. See all of my J-44 videos on You Tube! Thanks for checking in and stay tuned... Here are the links to my (2) NEWEST J-44 videos: "The J44 Project: Engine and Accessories Overview", www.youtube.com/watch?v=jJoSKJXdCKc and "The J44 Project: Turbine Nozzle Damage", www.youtube.com/watch?v=1zcHIdJ9bGA |
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