I've always wondered.........
Thread Starter
I've always wondered.........
An aircraft such as the phase three Shackletons and B-36s were fitted with both piston and jet engines. Presumably the aircraft had to carry two different sorts of fuel. Is that right?
Jet engines can run on petrol as well as kerosene. The ones I have experience of restrict petrol usage to a set number of hours and have an altitude restriction as well. Although I don't know specific details of the B-36, I would bet that they loaded just AVGAS (petrol) and used it for both types of powerplant.
In contrast, piston engines tend to stop if fed with kerosene.
In contrast, piston engines tend to stop if fed with kerosene.
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In the case of the B-36 only AV-Gas was carried, 115/145 octane. From what I remember my father telling me, that because the jet engines used AV-Gas, precautions had to be used when working on the jet engines due to the lead build up on the turbine blades.
As for other piston/jet combination powered aircraft, I don't know.
As for other piston/jet combination powered aircraft, I don't know.
In contrast, piston engines tend to stop if fed with kerosene.
But that's looong after the Shackletons and B-36s era...
So how was the turbine cooled on the J-47 engines? I trust all that lead would have an unwelcome tendency to clog up those holes in the blades in case film cooling was used and the engines would show rather short TBOs?
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So how was the turbine cooled on the J-47 engines? I trust all that lead would have an unwelcome tendency to clog up those holes in the blades in case film cooling was used and the engines would show rather short TBOs?
The fact that the jet engines were not started until basically the aircraft was in takeoff position and shut down as soon as they landed might have something to do with the cooling issue you speak of.
A personal side note. After I received my 727 type rating I called my father and informed him that now I was shoving three throttles forward to takeoff. He laughed and said I wasn't anything* until I shoved ten throttles foward for takeoff.
I thought about that for a second, then told him to wait just a minute, he never shoved ten throttles foward on the B-36, the FE did for the piston engines and the co-pilot handled the jet engines.
He shot right back saying, 'Don't bother me with details boy.'
* The word he used was not anything, but a word that started with an 's' wot we's not supposed to use here.
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yes JET engines can run on gasoline...indeed JP4 was a broad mix of fuels a bit of gas might have even been in that
and yes, you can't use JET fuel in a piston engine..I should say gasoline piston engine.
now...here is the nifty thing...in some turbine engines the greasy sort of kerosene/jet fuel keeps the fuel pumps lubricated.
and at least one turbine engine I used req'd the addition of lubricating oil to the gasoline...almost like a two cycle engine...butnot really.
six turning four burning was the call on the B36
and yes, you can't use JET fuel in a piston engine..I should say gasoline piston engine.
now...here is the nifty thing...in some turbine engines the greasy sort of kerosene/jet fuel keeps the fuel pumps lubricated.
and at least one turbine engine I used req'd the addition of lubricating oil to the gasoline...almost like a two cycle engine...butnot really.
six turning four burning was the call on the B36
Con-pilot,
thank You for the explanation. So it seems that fouling up the turbine blades and shortening the engines lives by feeding them leaded piston engine fuel was considered more desirable than installing a whole second jet fuel storage system, likely due to the relatively short times the jets were run during a flight.
thank You for the explanation. So it seems that fouling up the turbine blades and shortening the engines lives by feeding them leaded piston engine fuel was considered more desirable than installing a whole second jet fuel storage system, likely due to the relatively short times the jets were run during a flight.
Agreed.
Gas turbines can use gasoline, but if memory serves me, the Vipers on the Shackleton could not be run at maximum thrust because the turbine temperature limits would easily be exceeded.
An old friend "Beery" Weir (RIP) once told me that the maximum turbine temperature (reflected as jet pipe temperature) could be achieved with the rpm as low as 95%.
Gas turbines can use gasoline, but if memory serves me, the Vipers on the Shackleton could not be run at maximum thrust because the turbine temperature limits would easily be exceeded.
An old friend "Beery" Weir (RIP) once told me that the maximum turbine temperature (reflected as jet pipe temperature) could be achieved with the rpm as low as 95%.
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Mate of mine, at the time navigator on C130's, told me that in an emergency (war) they could use gasoline if desperate. Engines needed strip down/ inspection afterwards tho...
