One thing I find interesting about those huge engines, is that the contra-rotating props spun independent of each other when they were moved on the ground.
Are they directly connected with a gearbox or do they each have their own shaft and gearbox...?
GDB From United Kingdom, joined May 2001, 12718 posts, RR: 80 Reply 4, posted (4 months 1 week 5 days 22 hours ago) and read 4730 times:
A fascinating video, thanks.
Never seen one in the air, however they sent one to the static park of the RIAT in 1994. Parked it near a B-52 as well!
The TU-95 is a stark, intriguing looking aircraft, even more so if you ever get to see one close up.
It looked to me like some kind of huge metal Preying Mantis, maybe a Dragonfly, either way it looked almost organic .
francoflier From France, joined Oct 2001, 3196 posts, RR: 10 Reply 5, posted (4 months 1 week 5 days 20 hours ago) and read 4686 times:
Interesting. I thought those props were connected via a gearbox that made them turn in opposite direction at the same speed.
When the officer preflights, he turns both props in the same direction, meaning they're both independent and connected to 2 different turbine discs on concentric shafts.
Looks like I picked the wrong week to quit posting...
MrChips From Canada, joined Mar 2005, 911 posts, RR: 0 Reply 6, posted (4 months 1 week 2 days 10 hours ago) and read 3976 times:
Quoting francoflier (Reply 5): Interesting. I thought those props were connected via a gearbox that made them turn in opposite direction at the same speed.
When the officer preflights, he turns both props in the same direction, meaning they're both independent and connected to 2 different turbine discs on concentric shafts.
I'm fairly certain that the NK-12 has a single output shaft, rather than concentric output shafts.
Depending on the type of gearbox used (I'm assuming it's some sort of planetary gearing), it should be possible to turn both props in the same direction by hand while having them go in opposite directions while being powered by the gas turbine.
titanmiller From United States of America, joined May 2006, 86 posts, RR: 0 Reply 7, posted (4 months 1 week 7 hours ago) and read 3702 times:
Quoting MrChips (Reply 6): Depending on the type of gearbox used (I'm assuming it's some sort of planetary gearing), it should be possible to turn both props in the same direction by hand while having them go in opposite directions while being powered by the gas turbine.
That makes sense. Rotating them in the same direction at the same speed should result in the turbine (input) shaft remaining stationary.
That also means that in flight the props are equal torque, not equal RPM.
celestar From Singapore, joined Jul 2001, 245 posts, RR: 0 Reply 9, posted (3 months 6 days ago) and read 2201 times:
I read from somewhere that the technology behind the propeller engine for Tu 95 originated from captured German engineer and know-how - which is interesting to know that.
Tu95 is designed to fly long distance, over vast expanse of sea or land. I wonder if the Tu--95 was powered not by propeller but by gas engine, would it still be able to make that range - unrefueled mid-year? Is that long range a reason why the plane is a propeller driven? 1950s engine technology is probably not that fuel efficient, I think.
rwessel From United States of America, joined Jan 2007, 1991 posts, RR: 2 Reply 10, posted (3 months 5 days 23 hours ago) and read 2194 times:
Quoting celestar (Reply 9): Tu95 is designed to fly long distance, over vast expanse of sea or land. I wonder if the Tu--95 was powered not by propeller but by gas engine, would it still be able to make that range - unrefueled mid-year? Is that long range a reason why the plane is a propeller driven? 1950s engine technology is probably not that fuel efficient, I think.
To clarify, the Tu-95 is powered by four NK-12 turboprops (gas turbines).
But yes, the range on jets would have been drastically shorter given the turbojets of the time. Actually even now, if you didn't care about top speed, you'd be better off building a Mach .65 turboprop than a Mach .8 turbofan (which will do much better than a turbojet at subsonic speeds).
The approximately contemporaneous B-36 with the added four outboard jets, would always run with the jets shut down, except when the extra thrust was needed (takeoffs, maximum speed dashes through defended areas, etc.). The B-36's props being driven by pistons, unlike the Tu-95, and the B-36 was 100kts slower.
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