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Aero Precision provides OEM part support for military aircraft operators across more than 20 aircraft

pjvr99

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Posts posted by pjvr99

  1. Sounds like a wiring problem. Quickest fix would probably be to replace the inconel fire-wire in the engine and do a test flight.

    Question - had the engine been washed recently, i.e. inside the cowls? If the wire is chafed somewhere, water in the open area may be sufficient to momentarily trigger the system.

  2. I bet your performance was also around 113%. Not a problem - I had one about 2 years ago. Spent more than a week looking for the problem, until I noticed that the CDP matched the \'Air Start\' pressure guage. I confirmed by adding a third direct reading guage. You have one of the 1-in-1000 engines where the turbine, compressor and associated components match perfectly, coupled to the atmospheric conditions. Just make sure it\'s installed on an INBOARD position, and make a clear entry in the a/c forms. There\'s nothing wrong with it!!

  3. During the 80\'s, we got the call one of our birds(?) had a birdstrike, and was coming home for repairs. When she flew overhead, it looked like it had been painted with a gloss-coating. After landing we saw it was helo blade-tape over most of the leading edges - during a low-level leg they had surprized a flock of crow-sized birds.

  4. duckhunter04 wrote:

    We had a simular problem a few years back up here in Kodiak. Above crossover the TD and prop did it\'s job and everything was fine but below crossover and even into reverse we had a FF and TIT flux. Changed fuel control(2), fuel pump and then the TD Valve. Still did it and we needed the plane so we had to change the engine. What finally was the problem was a 3 way elbow/valve assy thats on the bottum of the TD valve and was allowing fuel to flow through it(wrong diection). Of coarse when we did the TD valve change we took the old elbow off and put new orings and installed on new TD valve. What a waste of man hours but I will never forget that again and always put new on new if available!!

    I remember something similar many moons ago .... still want to know whether the thread-starter resolved his problem

  5. DC10FE wrote:

    This has been around a while, but a friend sent it to me this morning & I think it needs to be read again.

    Don R.

    YOU MIGHT HAVE BEEN AN AVIATION MECHANIC IF YOU HAVE EVER WORKED AT OR DONE AT LEAST 1 OF THE FOLLOWING..........

    Ever drank castor-oil -- and not because of your mother.

    Slept on concrete under your jet.

    Ever said, \"Oh, yes sir, it’s supposed to look like that.\"

    You know what a pointy head is.

    You consider \"2380\" finger prints on food an \"acquired taste.\"

    Have sucked O2 to cure a hang-over.

    You know what JetA1 tastes like.

    Used a black grease pencil to fix a worn tire.

    You have a better store\'s supply in your coveralls or tool box than store\'s does.

    Used a piece of safetywire as a tooth pick.

    You refer to a pilot as a \"Control Stick Actuator.\"

    You\'ve ever been told to go and get \"a yard of flightline\" or a \"bucket of propwash\" from stores.

    Worked a 16 hour shift on a jet and then be told by operations that we aren\'t going to fly it till the next day.

    Know that R & R doesn’t always mean remove and replace, but raise and rotate.

    You\'ve ever said, \"As long as it\'ll start every other try, you\'ll be fine sir.\"

    You\'ve ever considered a traditional Thanksgiving dinner to be a sandwich off of the roach-coach in one hand and a wrench in the other.

    You know what a roach-coach is.

    And you like the food.

    You have ever sat underneath the heat exchangers to get warm.

    You\'ve ever towed airplanes around to match the board in operations.

    You believe that your \"bird\" has a soul.

    You talk to your bird (In your head still counts).

    Your spouse refuses to watch any aviation shows with you.

    You\'ve ever said, \"That nav light burned out when you turned it on this morning sir.\"

    You\'ve ever used a wheel chock as a hammer.

    The only thing you know about any city is where the good bars are.

    You know more about your co-workers than your own family.

    While watching commercials on TV, you look for tail numbers on your birds.

    You\'ve ever wished a pilot would just say \"Great bird, thanks.\"

    You\'ve ever passed gas in the work truck just to clear it out.

    You can\'t figure out why your 2 week advance per-diem is gone after 2 days.

    You can\'t get through a trip without finding an ATM.

    On a trip, the first place that you go is to the local store on a beer run.

    Most of your advance is spent in $1.00 increments in a \"club.\"

    You can sleep anywhere -- anytime, but as soon as the engines shut down you are wide awake.

    Everyone thinks that your job mainly consists of waving your arms at airplanes.

    You have scars on you that aren’t from your spouse or significant other.

    You\'ve ever used a seat cushion as a pillow.

    Been gouged by the pig tail end of a safety wired cannon plug.

    You\'ve ever stood on wheel chocks to keep your feet dry.

    You change underwear and t-shirts more times than your coveralls.

    Used dikes to trim your finger nails.

    Used RTV to fix a stripped screw.

    Made tampons out of paper towels for drain hole leaks.

    Knocked back a rivet stem that was hanging out of a drain hole.

    Wiped leaks down right before a crew show.

    The person held with the highest regard is the person that can drink a 6-pack with in a 5 minute period and not puke.

    You\'ve ever driven home after working a 36 hour shift, and don’t remember the drive.

    You tell your peers that you are getting a divorce and the first thing that they ask is \"selling anything?\"

    Everyone you know has some kind of nickname.

    I have highlighted more than 5, so I suppose I qualify :laugh:

  6. This sounds like a problem I had +-2 years ago. Problem is probably not in the prop at all (easily checked by removing the prop and doing a short run). Initially the problem was cured by changing the speed valve, I was venting intermitently, found during a man-on-stand check. The problem returned, becoming progressivly worse.

    See if you can attach an air-line and 160psi guage to the bleed valve system DOWNSTREAM of the speed valve. Attach another hose and guage to the CDP fitting. Do a run and compare the pressures from normal to cross-over. There shouldn\'t be more than 10psi difference, and there shouldn\'t be more than 5psi flux on either guage.

    Eventually my engine was found to have a bad tower shaft system, causing the flux.

  7. pjvr99 wrote:

    ..... bearing in mind when the prop does over-speed, the fuel conrol governor rpm is set according to fuel flow, which mostly is around 104.5% to 105.5%

    [email protected]$$ me: I should have stated that as when the prop does over-speed for fuel governing/pitchlock check ..... etc

  8. Different languages, different meaning, same words. US Navy guys talk about the \'fuel topping governor\', while the rest talk about \'fuel control governor\'. In South Africa and the UK we talk about \'topping up\' the tanks, while Americans talk about \'topping off\'.

    BTW fuel governor rpm for -A15/D22A 103.6% to 106.1%, and -7/D22 is 103.6 to 105.8%

  9. The test cell uses an A2D converter for the speed/RPM display which needs to be calibrated every 6 months. The procedure calls for 3 values 7Hz, 35Hz and 70Hz which displays as 10%, 50% and 100% respectivly. Thus at 100% the tach generator is putting out a signal of 70Hz. However, because the wires from the tach gen travel along various looms and harnesses, and is also connected to the synchrophase, it is extremely likely that no matter how accurately the guages are calibrated, there is going to be an element of error induced. When in doubt of the rpm guage, take a quick look at the frequency meter corresponding ......

  10. Natops1, you\'re almost right but the gauge error could go the other way too ....

    an exerpt from my post on HH

    .... I have never seen an engine below 95% at FI, and on those occasions a quick check has revealed FI blade angle to be in excess of 17.5° and/or LPS to be in excess of 25.5°. LPS gives itself away normally by being in excess of 5500\"lb when coming down from x-over .....

    ....As someone posted correctly, the speed valve does open at a significantly lower rpm on downshift than it closes on acceleration - generally 92 - 94% on upshift and 85 - 88% on downshift. I have on several occasions had the misfortune of having a speed valve close the bleed valves during starting, TIT quicly rises to start limiting TIT (810°C) at +-35 - 40% and stagnate.....

    Bottom line - if an engine is below 94% at GI or FI there\'s a good chance something is not set correctly, check RPM gauges, fuel control, coordinator and prop rigging and blade angles, and do a good performance run.

    http://p076.ezboard.com/RPM-Limitations/fc130herculesheadquartersfrm3.showMessage?topicID=746.topic for the full discussion

  11. Dan Wilson wrote:

    .....

    The TD system will fall into the equation when you get low voltage across one or more of the phases for the amp, I would tend to think that solid state will act worse with low voltage than any analog circuit will, computerized systems do all sorts of stupid things when you don’t feed them right. But as to how much more a solid state will contribute to the rollback problem vs. an old analog amp. I don’t really think they attribute a much larger problem with the solid state TD amp than with the old amp during a rollback or any other TD system problem .....

    Dan

    Dan, you\'ve said something here that is much closer to the truth than you think. I worked for an electronics company in the R&D lab. We had a number of problems with our devices initially, due to bad/low power supplies. Some of the devices were fitted to cars and trucks and were extremely unstable until we redesigned the power circuits for ESD problems, and more importantly brown-out.

    Brown-out is a low voltage condition where a circuit is still active but the voltage is too low for a clear signal/data to be transmitted and interpretted. Then, as you say, it does all sorts of stupid things. When I get back to work I will try to locate schematics for the TD amps and see if there is a brown-out reset function installed.

    It would appear from what you say, that in a low voltage condition the amp thinks there is too much fuel going in and therefore, starts cutting back. The problem may be that the comparators in the amplifier are incorrectly referenced .....

    ..... this may become an interresting project

  12. Casey, I sent you a PM a while ago. I have most of the Service News in .pdf format. I would like to upload them here but am a little wary of the response from Lockheed. Please advise me.

    Thanx

    PJ

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