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T56-A-9 vs T56-A-11


gmat
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All differences between the T56-A-9 and the T56-A-11 engines are internal. The T56-A-11 engine is a T56-A-9 power section which has been modified to operate with kerosene fuel. The T56-A-11 engine uses the same gearbox as the T56-A-7 engine. This gearbox is equipped with a lower gear ratio than the T56-A-9 engine. Externally, there is no difference between the two engines and there accesssoriess. The power section of the T56-A-11 engine is the same as the T56 -A-9 except the -11 uses a dual orifice fuel nozzle, p/n 6813716. These fuel nozzles are of a duplex nature designed with a spray tip with two concentric orifices and two spin chambers. These nozzles replace the T56-A-9 counterpart, p/n 6812991, which is a dual slot type incorporating one spin chamber and one exit orifice. The newer dual orifice nozzle results in greatly improved atomization of the fuel at cold temperatures and low fuel rates. A new fuel control, p/n 6826924 is used instead of the T56-A-9 fuel control p/n 6812563. The reduction gear configuration of the T56-A-11 gearbox is different from the T56-A-9 gearbox. The major difference is the gear ratio. The T56-A-11 gear box provides a 13.54 to 1 ratio which permits a slower propeller speed. Except for the slower speed, the internal changes to the gearbox do not result in any differences in the operating or maintenance instructions. Externally, the T56-A-11 gearbox is the same as the T56-A-9 and all mounting pads and accessories are the same. All performance specifications for the T56-A-9 engine apply to the T56-A-11. The weight of the -11 engine is approximately 100 pounds greater than the -9. The -11 engines had the Aeroproducts Model A6341FN-D1A, 3 bladed propeller.

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All differences between the T56-A-9 and the T56-A-11 engines are internal. The T56-A-11 engine is a T56-A-9 power section which has been modified to operate with kerosene fuel. The T56-A-11 engine uses the same gearbox as the T56-A-7 engine. This gearbox is equipped with a lower gear ratio than the T56-A-9 engine. Externally, there is no difference between the two engines and there accesssoriess. The power section of the T56-A-11 engine is the same as the T56 -A-9 except the -11 uses a dual orifice fuel nozzle, p/n 6813716. These fuel nozzles are of a duplex nature designed with a spray tip with two concentric orifices and two spin chambers. These nozzles replace the T56-A-9 counterpart, p/n 6812991, which is a dual slot type incorporating one spin chamber and one exit orifice. The newer dual orifice nozzle results in greatly improved atomization of the fuel at cold temperatures and low fuel rates. A new fuel control, p/n 6826924 is used instead of the T56-A-9 fuel control p/n 6812563. The reduction gear configuration of the T56-A-11 gearbox is different from the T56-A-9 gearbox. The major difference is the gear ratio. The T56-A-11 gear box provides a 13.54 to 1 ratio which permits a slower propeller speed. Except for the slower speed, the internal changes to the gearbox do not result in any differences in the operating or maintenance instructions. Externally, the T56-A-11 gearbox is the same as the T56-A-9 and all mounting pads and accessories are the same. All performance specifications for the T56-A-9 engine apply to the T56-A-11. The weight of the -11 engine is approximately 100 pounds greater than the -9. The -11 engines had the Aeroproducts Model A6341FN-D1A, 3 bladed propeller.

Wow I guess that answers his question.

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Generalsmoke,

Thank you for you explanation. It is excellent and I am ashamed to say that it is pretty overwhelming for my limited knowledge about engines. But thank you again. Do you know when the -11 started to be used on C-130As?

Best wishes,

Grant

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  • 3 weeks later...

Your right Sam its all kerosene but, All the different grades have stuff (additives) in it to change things like, flash points, static inhibitors, densities, preservatives, even good ol gasolene as Tiny mentioned in another thread. The list goes on and on. And $$$$$. The performance gains Generalsmoke is talking about probly made the mods pay for themself in a hurry.

Edited by mongo
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Correction to your prop speeds for the dash 11 engine. The prop turns faster using the -7 geargox. The three bladed prop turns at 4 bladed speed and is noisier as a result.

The official description of the kerosene used in the -11 is "super clean kerosene" as defined by the RAAF Fuels and Lubricants Handbook.

The engine is actually an Allison 501D13 power section fitted with a -7 gearbox. It runs the same max torque as the -7 and gives a 20kt higher cruise for the same power settings used for A models. As per Allison manual 11R4, the engine is limited to 4,300HP in the test cell, but runs the 4,050, the same as the -7. The -11 engine does not use USAF T.O.s for overhaul, but does for general maintenance. Overhaul is by Allison manuals 11R1 thru 4.

I have a full set of these manuals that I have used for over 20 years when working on the -11 engines.

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  • 1 month later...

According to the SPADL there are almost no parts interchangeable between the -9 and -7 hot sections and -7 and -15 hot sections. The -7 turbine is so highly stressed that they fitted a scatter shield to them so they wouldn't hit the airframe when they suffered an uncontained failure. The -9,-11 and -15 don't have a reputation for uncontained failures. The -7 turbine loads was the main reason the B and on had the engine nacelle moved forward several inches. It kept the turbine plane in front of the spar webs and planks if it failed.

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And 1958 thru 1959 would be years of production. As the RAAF C130A were the last to be produced except for some RC130A's then all engines except maybe for some additional spares would have been produced in the production years.

The RAAF made the engine more reliable by restricting the Cruise TIT which extended the life without premature change outs greatly.

AVTUR which is a British spec equivelant to JP1 was our normal diet, but of course we used JP4 out of US bases and Vietnam. The made differance I believe is that JP1 had no petrol in it.

Earl Cherry has been operating the only flyable RAAF C130A for so many years and runs his on JP4 with no problems.

Regards

Col

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