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pjvr99

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Posts posted by pjvr99

  1. Very cool video!!!

    Have you used a different pump housing?

    Next on the 'to-do' list

    In HSGI if you retard the throttle towards reverse does the RPM increase or overspeed or does the fuel flow and blade angle change?

    What happens if you leave the engine at HSGI for an extended time?

    TIT?

    RPM?

    Tq was/is 6000.

    Moving to reverse is not a problem, torque, ff, rpm normal. Got to be very careful coming

    back as the torque picks up very quickly. If left long enough the rpm will decrease

    below 94%, risking flameout. TIT rises some

  2. th_VIDEO0295.jpg

    Vid as promised. Don't worry about the odd movements, it's the way my HTC

    captures the movement. Sound is not recommended, except to determine up-

    and downshift. Starts of in NGI then goes to LSGI, back to NGI, and finishes

    at LSGI. +-1minute, 8MB on Photobucket

  3. Last effort maybe “pin†the valve housing to see if your issue stops…. Then pin the rigging (work your way out) to find where it is malfunctioning....

    Installed one of the last props we ran, engine is perfect. This is the only thing we didn't

    do because we were out of time - priority engine. We will be doing more troubleshooting

    in the next few days, then this will be checked also. I did move up close to the engine to

    see if there was any linkage movement on the controls - nada. Also shutting the engine

    down from NGI didn't show anything as the blades go back as soon as the engine slows.

    Will post a vid later today ......

    PJ

  4. Since the valve housing had been changed with no effect:-

    1- De-activate NTS bracket by keeping the gap at maximum, and check your engine.

    Done - no change

    2- Check your NTS bracket on the valve housing cover assembly for bending.

    Done - also changed out covers

    3- Remove the electrical plug (the one for the feather solenoid valve) and recheck.

    Hope those steps will help isolating the affected area of the NTS system.

    Done - removed all 5 cannon plugs. Ran a purely mechanical prop, no anti-icing, no aux

    feather motor, no pressure cutout, no low light, no synchrophaser, no feather solenoid

    just for kicks, I'd start the engine null and see what happens

    Did that - no difference

    I could also guess internal leakage in the prop

    Looking into that

    always the possibility of a malfunctioning fuel control

    Removed from equation by installing a known good prop

    Thanx for the feedback so far. When/if we find out what it is, I'll get back

    PJ

  5. Hey HerkyWorld

    Got an unusual situation here. Engine starts normal, LSGI torque set correctly. When

    the LSGI button is pulled to upshift to Normal Ground Idle, torque stabilizes for a

    moment at +-1200"lb ........ then increases to +-6000"lb, rpm decays to 94%, and

    TIT increases. Also prop noise indicates the engine is labouring. When LSGI button

    is pushed in, everything returns to normal. Standing on the blade line, you can see

    the pitch change occurring.

    Changed out valve housing, pitchlock regulator, and low pitch stop. Also removed all

    cannon plugs to remove electronic influence - no good! Stays the same .....

    Anyone out there seen this before? any ideas, theories ........ anything?

    Have a great day

    PJ

  6. Hey HerkyWorld

    Got an unusual situation here. Engine starts normal, LSGI torque set correctly. When

    the LSGI button is pulled to upshift to Normal Ground Idle, torque stabilizes for a

    moment at +-1200"lb ........ then increases to +-6000"lb, rpm decays to 94%, and

    TIT increases. Also prop noise indicates the engine is labouring. When LSGI button

    is pushed in, everything returns to normal. Standing on the blade line, you can see

    the pitch change occurring.

    Changed out valve housing, pitchlock regulator, and low pitch stop. Also removed all

    cannon plugs to remove electronic influence - no good! Stays the same .....

    Anyone out there seen this before? any ideas, theories ........ anything?

    Have a great day

    PJ

  7. Friends, I am looking for someone who can help me to help some South African Air Force friends. They received some F models from USN and little to no data. Date received was circa 1996.

    They are primarily interested in the amount of mods (if any) performed to the OW's. If you know someone who would share their sagely wisdom please ask them to contact me at [email protected] or through this site.

    Sorry but this is not a paying gig; just a favor to some old Herc friends.

    thanks

    C-130F (ex-USN)

    410 c/n 3636

    411 c/n 3660

    412 c/n 3696

    Were not flown after arrival in SA due to corrosion and other issues.

    C-130B (ex-USAF)

    408 c/n 3526

    409 c/n 3530

    These two were upgraded to C130BZ along with the other original SAAF birds

  8. Natops, you hit the nail on the head. If the engine is being started with +-80psi instead

    of 30 to 35psi the spin up time is often markedly shorter. In turn, 50psi fuel pressure

    to cut off enrichment is also reached quicker. It is thus possible that the window of

    opportunity to see anything on the gauges is very small. A hot engine starts and spins

    up somewhat faster than a cold engine.

    Main tank boost pumps operate at 18 - 24psi, while aux and external at 30 - 40 psi. Basically

    this is already fuel pressure in the manifold, meaning that the time available to see some-

    thing before 50psi is reached, is reduced.

    I know, I'm looking for something highly improbable, but sometimes it's just those little things

    that trip us up. I honestly do hope it's a bad cockpit switch or broken wire ....... something

    regular and simple

  9. Another thought: if the starts are being done on the ground, is this engine being started

    using APU/GTC bleed air, or engine bleed air? And are the tank boost pumps being used,

    more specifically aux and/or external tanks?

  10. APU came from overhaul, ran through test cell - all good. Installed on aircraft, bleed air

    on, but no load, there is a 5 - 10psi pressure surge, small EGT and RPM flux. When a load is

    applied (eg aircon pack), it stabilizes. Removed and sent to test cell, again nothing could be

    found. Installed on another aircraft, has the same problem. Replaced the load control valve,

    but still the same.

    Anyone have any ideas ...??

  11. Believe me, it was the last thing I would suspect. However, a bit of a give-away

    was the 30psi oil pressure at 900° TIT and 75° oil temp. My thoughts were tending

    to a break/crack in the ADH front cover plate or a failure of the seal between the

    pressure and scavenge sides of the pump ....... but that's how knowledge and

    experience is accumulated

  12. ..... The strangest uncommanded shutdown i had turned out to be the T.D. amp. Engine shutdown and wouldn't start. Started in null fine and ran up to full power. Swich back to Auto and engine shutdown. Amp change cured the problem. Good luck.

    Had this one too, many, many moons ago .......

  13. Two areas to look at here:

    1. left hand harness could have broken wires on the speed switch c/plug. Swap it out,

    see what happens;

    2. a little more difficult to determine, but maybe a bad tower shaft, bearings, or gears. Hook a direct

    reading gauge to 5th/10th stg bleed valves, and run the engine. Pressure should be same

    as CDP, but could be as much as 10psi lower. The thing you're looking for is flux exceeding

    about 5psi. At the same time keep an eye on TIT and fuel flow. excessive or erratic fluctuation

    would give an idea

  14. On a whim today, I did a TIT calibration. Shooting TIT from the T-block, starting at 50°C and

    incrementing 50°C up to 1100° all readings within 2°C. Before and after indications of OAT,

    TIT and fuel temp was 30°C, 31°C and 34°C (fuel was higher because the sun had already

    gotten to the pump). I hooked up my relay and ran the engine @ 900°C and only had a 1°C

    change .....

    Bob, you you need to tell your FE's to concentrate on the important things:-

    1. Wine

    2. Women

    3. Song

    :-)

  15. Ah, now that's a different game, Bob. First thing to realize is that no 2 gauges are going to

    give exactly the same reading. Next thing would be that that low down, there is no

    guarenteeing the thermocouple's accuracy. Also effect of air movement through the engine,

    swirling around the fuselage, etc. Sunrise on the left wing?

    In the test cell, GENERALLY, early morning has TIT, OAT, fuel and oil temps within 1 or 2

    degrees. Later in the day, this can change by a substantial amount.

    Why is the FE concerned about this? The TIT system measures measures combustion

    temperature, and is set up for an individual engine.

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