pjvr99

..... 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%

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%

OK, lets ask the question this way - are there any forum members or readers that work these EPC birds?

Sounds like fun ..... is it already fitted with the EPC system on the 54H60 prop? I\'m actually looking for more info on 54H60 with EPC

Thanx

PJ

Hey guys

Any further news on these EPC birds? Are they still being demodded? Any input from active operators/users/techs would be extremely welcome.

Tnx

PJ

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 ......

Merry Christmas everyone, and a happy New Year. Drive safely if going away for the holidays .....

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

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

Haven\'t done a cooling turbine in nearly 20 years, but remember they use engine oil Mil-L-23699 / Mobil Jet II or whatever engine oil you use

That\'s the full set, and what I have too

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

South African Air Force always drained residue (used it to wipe down engine cowls, etc), SAFAIR always drained, and Saudi Air Force drains. Reason given - to reduce fire hazard

I have most in .pdf - which ones do you need?

Gmon wrote:

You cant be too sure of how much is in the propeller unless you serviced a dry prop.

Absolutely correct! Yet given that I get around 50 dry props a year, 40 of them take 6gal of fluid, 8 will take 5gal 2qrt, and the remaining 2 will take up to 7gal. The only consistant thing being the point at which the feather cutout switch actuates, and when the low light goes off (if the level switch is functional). So the end result is, you can do whatever you like, as long as it is IAW applicable TO or MM. You need to be sure in your mind that there is sufficient fluid in the prop - it is your signature/stamp in the forms, therefore your @ss is on the line.

It is my experience that a prop serviced now, checked as overserviced (atmospheric sump), 10 minutes into the run suddenly has low oil light, and will take another 2 - 3 qrts; or, standing overnight will be low the next day. Each prop is different and needs to be treated as such.

I feel more comfortable using the pressurized sump, because I often work alone.

Madmax, we have over the last +-2years had a rash of float switch failures. Zero time intalled during prop overhaul or build-up, fails in test cell, or shortly after prop installation on the wing, or after replacement. These float switches are a very unreliable design

Must be your PC/ISP connection, I\'m getting really good speeds in the Magic Kingdom (HSDPA 3G modem)

Nice pics Dan, these guys don\'t look too stressed out, do they ? By the looks of things, #1 & #4 blades are at in-flight angles, while #2 & #3 are at feather-shutdown position.

Was the aircraft mothballed or abandoned?

Was it hangared or in open storage?

What type of atmospheric conditions prevail, ie, North Atlantic

coastal, Florida coastal, desert?

Were the engines and GTC removed for reuse?

Lkuest, the only time I ever saw/heard of decouple on take-off, was a safety coupling that disintegrated. As you say, highly unlikely at T/O power unless engine had already flamed out and prop was driving the engine.

B) Antonovs and Ilyushins also have an unfortunate tendency to suffer from decelration trauma, due to poor maintenance and lack of parts. They\'ve been taking a beating in Africa recently, where the Antonovs have been completely banned in DRC airspace. So somehow this must also be the fault of the US:unsure: :unsure:

I believe NATOPS called it right. I fitted the new cooler today, and temperature maxed out at 84°C after 20mins at 1000°C TIT.

FYI engine has 1750hrs, vibes are 0.6, 0.5 & 0.7 resp. for turbine, compressor and RGB. No SOAP.

Being paranoid doesn\'t mean they aren\'t out to get you . I have been told I\'m very picky about what\'s acceptable and what\'s not in the cell. I just like to get it as close to perfect as I can. The oil system is acknowledged the most difficult system to troubleshoot, which is why we should go the extra mile when problems occur.

Thanx for your input guys. Really appreciated

Have a great day

PJ

Hi guys

I got a problem I need your thoughts with. Recently one of our birds twice turned back after oil temperature exceeded +-90°C at altitude.

History: The aircraft just completed ISO, and post-dock runs had oil temps getting up to 100°C at ground idle. OAT was in mid 40\'s. Two different oil coolers were fitted, and oil tank was drained and serviced with new oil. After this it was released.

The next mission off base the in-flight problem occurred, and the engine was removed for test cell evaluation.

In the Cell I started by draining all the oil from tank, RGB, ADH, oil cooler, and motoring the engine to empty all the oil hoses and tubes, and changed all filters.

I then serviced the tank, and motored the engine to refill hoses, tubes and filters, and then refilled the tank. I noticed that the quantity had gone down about 3 gallons during motoring. I then started up and proceeded to do a back-pressure run at 900°C TIT. Only the Fuel Heater back pressure was high at 15psi, but the temperature did go up to 93°C. Immediately after shutdown I checked the oil temperature in the tank with a digital thermometer, and confirmed 93°C. Also the oil qty had increased by 2gallons over the prestart qty.

The next day, I motored the engine again before starting, and noted the qty dropped by 2 gallons. I fitted all the panels, started up and accelerated to 900°C TIT. I ran the engine for 30mins and the temperature went up to 92°C. I throttled back to flight idle for 10 mins and the temperature dropped to 85°C. I then accellerated to 1000°C TIT. Oil temp after 30mins was 97°C, and I also noticed that the lighthouse pressure had increased slowly from 3\"Hg to 4\"Hg. Oil qty after shutdown was the same as before motoring.

I then changed the turbine scavenge pump, as it appeared to be a poor scavenge system causing retained oil to overheat. When I removed the pump, I found the \'O\'-ring on the spline shaft had completely carbonized. The oil temp dropped by 2°C, and the qty during the run was 1/2gal higher than before. I then changed the #2/#3 bearing scavenge pump, but only got 1°C improvement, and no qty improvement. I then decided to go for broke, and had the PS main oil pump and figure 8 seal changed, and had the turbine removed to inspect the oil tube seals inside the lighthouse. These seals were also carbonized.

Today, after motoring qty was only 1 gallon down - normal. I started up, went to 900°C TIT. After 30 mins, oil temp went 87°C. After 10 mins at flight idle, temp went down to 80°C. At 1000°C TIT, temp went up to 89°C. Also the qty during the run was only 1.25gal below prestart qty, and no increase in lighthouse pressure.

So, big improvement all round. But I still feel that the temperature should be somewhat lower. I have received a brand new, out-of-the-factory oil cooler, which I will install tomorrow, and give it the works .

Any ideas and/or suggestions from you would be welcome.

Thanx. Have a great day

PJ

According to the 2-11, run the prop feather to full reverse 2-3 times. On the last reverse cycle hold the condition in air start, while the outsider removes atmospheric dipstick, then move throttle to ground idle. Replace dipstick while running aux motor for 10 seconds. Remove dipstick and check for fluid. Full mark is +-1 inch off the bottom.

(From memory a long time ago .....) Pressurized sump - feather the prop and wait for pressure to deplete. Check dipstick for quantity. If no dipstick available, use a 6\" screwdriver and feel for the ridge inside the well. If you remove the screwdriver and it has fluid you have sufficient.

For me the pressurized sump was always the easier and more accurate way .....

BTW, the Navy P3\'s use a low pressure switch on the pumps to determine prop oil qty

Thanx Casey and Bob

Unfortunately 90% of my plane pics (including ALL my Herk pics) were lost to a HDD failure 5 years ago - so I\'m collecting again.

You guys have done an outstanding job in the few weeks this site has been running.

Have a great day.

PJ