Lightly flown Tu-95 Bear for sale...

[Mig_Driver]

http://arstechnica.com/information-tech ... w-mileage/

Can you believe it?

[Bruce Hamilton]

Listing removed from eBay, wonder why...

[pjc747]

Listing removed from eBay, wonder why...

The German government has a Cold War era moratorium on the private sale of Russian mainline bombers...

[Lewis - A2A]

Would love to see a Tu-95 Bear up close would be quite the experience

[pilotgod]

If I were to own a Bear, wonder if the US Navywould extend the same courtesies to me if I buzz one of their carriers as they did the USSR. While I bet I get the same escort, I doubt they'll just let me go home.

[pilottj]

Talk about breaking noise abatements lol. I think Bear crews go deaf after serving aboard that noisemaker.

Turn DOWN your speakers for this LOL
[youtube]http://www.youtube.com/watch?v=q-2dfEc70gU[/youtube]

Still I hope at least museum could pick up this Bear for sale.

Cheers
TJ

[Great Ozzie]

If I were to own a Bear, wonder if the US Navywould extend the same courtesies to me if I buzz one of their carriers as they did the USSR.

Decades old Cold War games (in this example) the Soviets would play with the U.S.

First pic is one I took from (I think) the USS New Orleans during a WESTPAC deployment (western pacific) in the early '80s.

Second pic came from a buddy in my platoon but located on another ship in the PHIBRON (Amphibious Squadron i.e. multi-ship deployment).

[DC3]

I don't see many aircraft with tandem props. It must be a maintenance nightmare to maintain them. I wonder how efficient they really are. How much extra speed do they add to the aircraft? Is there any online reference about this type of prop setup?

[AKar]

Turn DOWN your speakers for this LOL

Interesting video. I've always thought that the NK-12 would be a single-spool engine with a horrendous gearbox thing for the props, but the shutdown part in this video suggests that the propellers actually are independent spools from each other. Can that really be, or do they rotate fast enough even when shut down for the video frame rate to play tricks?

Looks like I need to put some money aside for Yefim Gordon again.. Anyway, a magnificent aircraft!

Edit:

I wonder how efficient they really are. How much extra speed do they add to the aircraft? Is there any online reference about this type of prop setup?

According to Wikipedia, they "have been found to be between 6% and 16% more efficient than normal propellers." If I recall what I've been told, we are speaking of efficiency gain of about 10 %, so that might be. Unfortunately, the source referred in Wikipedia is behind ftp password. But I got no reason to believe they would not be very efficient, as they are able to redirect the radial component of the propeller airflow much like fan guide vanes used in turbofan engines.


-Esa

[DC3]

Found this on NASA website:

Tests of 2-blade, adjustable-pitch, counterrotating tandem model propellers, adjusted to absorb equal power at maximum efficiency, were made at Stanford University. The characteristics, for 15 degrees, 25 degrees, 35 degrees, and 45 degrees pitch settings at 0.75 R of the forward propeller and for 8 1/2%, 15% and 30% diameter spacings, were compared with those of 2-blade and 4-blade propellers of the same blade form. The tests showed that the efficiency of the tandem propellers was from 0.5% to 4% greater than that of a 4-blade propeller and, at the high pitch settings, not appreciable inferior to that of a 2-blade propeller. It was found that the rear tandem propeller should be set at a pitch angle slightly less than that of the forward propeller to realize the condition of equal power at maximum efficiency. Under this condition the total power absorbed by the tandem propellers was from 3% to 9% more than that absorbed by the 4-blade propeller and about twice that absorbed by a 2-blade propeller.

http://ntrs.nasa.gov/archive/nasa/casi. ... 014144.pdf

Doesn't seem like much gain for the maintenance nightmare it must have been.

--

[cflord]

The old Bear needs to be in a museum some where. I'd like to see her as a flying museum; but she is probably too expensive to operate. The movie clip of the Bear flying is awesome. I liked watching the counter-rotating props!

Keep the shiny side up and the dirty side down!

Ret SMSgt Cliff Lord - C-130 Flight Engineer & Mechanic

[pjc747]

Found this on NASA website:

Tests of 2-blade, adjustable-pitch, counterrotating tandem model propellers, adjusted to absorb equal power at maximum efficiency, were made at Stanford University. The characteristics, for 15 degrees, 25 degrees, 35 degrees, and 45 degrees pitch settings at 0.75 R of the forward propeller and for 8 1/2%, 15% and 30% diameter spacings, were compared with those of 2-blade and 4-blade propellers of the same blade form. The tests showed that the efficiency of the tandem propellers was from 0.5% to 4% greater than that of a 4-blade propeller and, at the high pitch settings, not appreciable inferior to that of a 2-blade propeller. It was found that the rear tandem propeller should be set at a pitch angle slightly less than that of the forward propeller to realize the condition of equal power at maximum efficiency. Under this condition the total power absorbed by the tandem propellers was from 3% to 9% more than that absorbed by the 4-blade propeller and about twice that absorbed by a 2-blade propeller.

http://ntrs.nasa.gov/archive/nasa/casi. ... 014144.pdf

Doesn't seem like much gain for the maintenance nightmare it must have been.

--

Ships have been using contra-rotating propellers for a long time, and are quite reliable now, and I think the same goes for these Russian systems. The Russians have been using this plane for nearly 62 years; its the same age as the Boeing B-52. If they've kept a turboprop bomber with such a configuration for so long, especially seeing as they have built jet bombers since, it must work pretty reliably and cost-effectively. The Americans had trouble with the configuration, however the British worked it out in many iterations of the Griffon-based Spitfire, and the Russians to boot. If NASA were to invest the time and money into developing their own contra-rotating system, I'm sure it would work as well or better than the Russians'. But we have jets, and since sexagenarian turboprops aren't available to us, they don't have a cost effective edge.

[pilottj]

An interesting offshoot is the contra-rotating prop fan of the Antonov An-70. Quite a unique sound too, kinda sounds like a diesel lol.

http://www.youtube.com/watch?v=NhJNllbXBXo
http://www.youtube.com/watch?v=lAafPSWzpOw

[Dooga]

Turn DOWN your speakers for this LOL

Interesting video. I've always thought that the NK-12 would be a single-spool engine with a horrendous gearbox thing for the props, but the shutdown part in this video suggests that the propellers actually are independent spools from each other. Can that really be

As this is a turboprop I assume that the two propellers simply have independent drive shafts coupled to counter-rotating turbine sections in the engine. Not really that complicated...

[AKar]

As this is a turboprop I assume that the two propellers simply have independent drive shafts coupled to counter-rotating turbine sections in the engine. Not really that complicated...

The reason I'm surprised if it actually is so is that as far as my knowledge goes, almost all Soviet turboprops of that era were of single spool design. Also, the sparse internet data, pictures and videos of NK-12 generally indicate it would be a single spool. And even the Progress D-27, which appears to have a twin spool gas generator section and separate power turbine, has both propellers mechanically connected. So I'm not yet buying that the Bear's props would be independent from each other.

-Esa