Tupolev Tu-95 Bear

[Triton]

"Rare inflight footage from inside a Russian Tu-95 shows the Bear’s coaxial contra-rotating propellers"
Feb 15 2015

by David Cenciotti

Source:

Rare inflight footage from inside a Russian Tu-95 shows the Bear's coaxial contra-rotating propellers

Fine piece of machinery. Here's an interesting footage filmed form inside a Russian Tu-95 Bear bomber like the ones that skirt northern Europe's airspaces

theaviationist.com

Here’s an interesting footage filmed form inside a Russian Tu-95 Bear bomber like the ones that skirt northern Europe’s airspaces every now and then.

Although it does not show anything special about the plane, the rare video lets you have a close look at the eight-bladed coaxial contra-rotating propellers Kuznetsov NK-12 engines of the Tu-95.

Indeed, the only propeller-powered strategic bomber still in operational use today, features the typical two propellers, arranged one behind the other, which increase efficiency and performance.

An in-flight, engine shutdown and restart cycle can be seen in the clip.

View: http://youtu.be/aZG-HLU48LU

 

[_Del_]

Looks like a stroboscopic effect as opposed to a shutdown or restart, but a cool video nonetheless.

 

[Michel Van]

Looks like a stroboscopic effect as opposed to a shutdown or restart, but a cool video nonetheless.

This bizarre stroboscopic effect, is produce by today digital camcorder,
There CCD are unable to take high speed like rotating propellors.

 

[CxxTxx]

I saw this unanswered question on another forum, and I've always wondered the same thing so I decided to post it here.

"Why was the Tu-95 Bear designed with 35-degree swept wings? The Bear is fast, but not that fast, that is, it cannot achieve the near supersonic speed that would warrant that degree of sweep. Modern airliners are capable of speeds that exceed the Tu-95, but their wing sweep is much less. Is there something about the NK-12 turboprops that require that sweep, or is the design merely an artifact of when the aircraft was designed (in the early 1950’s?) If the design is merely an artifact from 1950’s Soviet aerodynamic research, why were the 35-degree wings retained in the Tu-142 series of aircraft? Also, are the contra-rotating propellers (the tips of which exceed the speed of sound) still the best way to go given the wide cord six and eight blade props are a proven technology and widely available?"

Good questions. Does anyone have insight into these?

 

[TomS]

The Bear is a bit faster than Mach 0.8 (officially Mach 0.82, IIRC), very close to the large jet aircraft of the era. The B-47, B-52, and Boeing 707 were swept at almost exactly the same angle, and were only a few percent faster. The rationale for the swept wing is the same in both cases -- it reduces transonic drag. Modern airliners still tend to have sweep angles bwtween 30 and 35 degrees and speeds around Mach 0.85 -- not very far at all from the Bear.

Clearly large contraprops aren't a preferred solution anymore or we'd see other aircraft with them. The closest we see are proposed open-rotor engines, but they aren't gaining ground yet.

 

[Machdiamond]

The wing sweep main purpose is to move the wing box structure forward of the bomb bay, which occupies the full depth of the fuselage and needs to be near the aircraft center of gravity.
For the contra-rotating propellers, it depends on the design requirements. It may still make sense today in some cases. It is interesting to see that the A400M does not have those while the An-70 did. I would say that it is always better to avoid complexity if you can.

 

[malipa]

Furthermore a fairly large part of the wing is subjected to the wake of the engines, which accelerate the air as well. The angle actually decreases after the part of the engines ;P

 

[flateric]

35 degrees was a 'magic angle' recommended by TsAGI

 

[Steve Pace]

Its sweptback flying surfaces sure do add to its overall beauty though. -SP

 

[AeroFranz]

Part of the reason is also airfoil technology. Today's airliners employ airfoils that delay compressibility effects without needing as much sweep. For a given cruise Mach number, an A350 needs less sweep than say, a 707. I don't know exact numbers, but it could be as much as 5-10 degrees.

 

[malipa]

The A350 actually has almost no wavedrag.

 

[Sundog]

For the contra-rotating propellers, it depends on the design requirements. It may still make sense today in some cases. It is interesting to see that the A400M does not have those while the An-70 did. I would say that it is always better to avoid complexity if you can.

However, don't forget the A400M propellers rotate opposite each other on each wing. The inside propellers, 2 & 3, rotate top away from center line (the fuselage) and the outer two, 1 & 4, rotate top away from center line (the fuselage). Which counter acts the torque and keeps the airflow over both wings symmetric about the center line as well. Even though you don't get the benefit of taking the swirling angular momentum out of the propeller slip stream, you sure save a lot of weight without the complex gear boxes. Although I'm sure you personally knew most of that, I just wasn't sure if you knew about the opposite rotation of the propellers on the A400M.

 

[CxxTxx]

However, don't forget the A400M propellers rotate opposite each other on each wing. The inside propellers, 2 & 3, rotate top away from center line (the fuselage) and the outer two, 1 & 4, rotate top away from center line (the fuselage). Which counter acts the torque and keeps the airflow over both wings symmetric about the center line as well. Even though you don't get the benefit of taking the swirling angular momentum out of the propeller slip stream, you sure save a lot of weight without the complex gear boxes. Although I'm sure you personally knew most of that, I just wasn't sure if you knew about the opposite rotation of the propellers on the A400M.

I didn't know any of it....

Its sweptback flying surfaces sure do add to its overall beauty though. -SP

Agreed, the Bear is a sublime work of art.

 

[Machdiamond]

Yes Sundog that is counter-rotating propellers as opposed to contra-rotating.
Like the Piaggio Avanti, Piper Navajo, Seneca and Seminole, etc.

 

[CxxTxx]

Russian Bears Saved From Extinction

http://www.strategypage.com/dls/articles/Russian-Bears-Saved-From-Extinction-5-14-2015.asp

 

[Basil]

CxxTxx,

during cruise speed the propeller tips of the NK-12 remain well below the speed of sound despite the large propeller diameters; only during high speed dashes the addition of forward and rotational speed makes the tips reaching low supersonic regions.

For the A400M engines a contra-rotating propeller gearbox was designed by a German engineering bureau (which traces its roots back to the propeller gear design of the Jumo 022) but finally a single rotation solution was chosen. Arithmetically the contra-rotation offered a slightly higher propulsive efficiency at high speeds.

 

[Grey Havoc]

In current events:

"Meanwhile, Russia says it has has started deploying its “strategic” aviation - long range Tu-95 and Tu-160 bombers flying eight-hour missions out of Mozdok and Engels airbases in southern Russia. Several have already carried out their first strikes, according to today’s briefing."

Daily Telegraph

 

[TomS]

This bizarre stroboscopic effect, is produce by today digital camcorder,
There CCD are unable to take high speed like rotating propellors.

It's not new to CCD cameras. Film cameras do the same thing when the prop RPMs are close to a multiple of the camera's frame rate. You can even see it in person sometimes. Essentially, people have a frame rate too, though it is less hard-wired than a camera's.

Wagon-wheel effect - Wikipedia

en.wikipedia.org

 

[Hobbes]

The footage taken of the right wing shows the wagon wheel effect, with props looking like they're turning slowly while they actually run at full speed. The motion blur is evident. In the shot of the left wing, the propeller blades are much sharper, so I suspect they're actually stopped. You can see the extreme blade pitch (i.e. they're feathered). Unusual that they would shut down both engines on the left side, though.

 

[gtg947h]

The footage taken of the right wing shows the wagon wheel effect, with props looking like they're turning slowly while they actually run at full speed. The motion blur is evident. In the shot of the left wing, the propeller blades are much sharper, so I suspect they're actually stopped. You can see the extreme blade pitch (i.e. they're feathered). Unusual that they would shut down both engines on the left side, though.

Extreme blade pitch is normal, at least...

http://i1.wp.com/news.usni.org/wp-content/uploads/2015/02/Russian_Bear_H_Aircraft_MOD_45158140.jpg

 

[Flyaway]

Watch the maiden flight of the modernized Tu-95MSM:

View: https://youtu.be/0EHJzJw9ZMA

 

[QuadroFX]

First Tu-95MSM actually - deep modernized Tu-95MS: modernized engines, new electronic warfare, new weapons, according Tupolev design bureau.

 

[sat_dxer]

First Tu-95MSM actually - deep modernized Tu-95MS: modernized engines, new electronic warfare, new weapons, according Tupolev design bureau.

Hope this variant keeps using the old Morse key:

https://upload.wikimedia.org/wikipedia/commons/9/9c/Cockpit_of_Tupolev_Tu-95MS_%285%29.jpg

 

[kaiserbill]

First Tu-95MSM actually - deep modernized Tu-95MS: modernized engines, new electronic warfare, new weapons, according Tupolev design bureau.

What did they do with the engines?
FADEC?

 

[fightingirish]

The new engines NK-12MPM with also the new propellers have less vibration than the older ones. So the Tupolew Tu-95MSM has now better performance especially during take-off.

[...]“The NK-12MPM engine developed by the Samara-based Kuznetsov public company (part of the UEC [United Engine Corporation] within Rostec) is a modification of the NK-12MP, the world’s most powerful (15,000 hp) serial-produced turbo-prop engine,” says a statement obtained by TASS last year.

“It allows improving the aircraft’s take-off characteristics and increasing the load-carrying capacity and the flight range of the missile-carrying bomber. The new powerplant uses more powerful propellers created by Aerosila Research and Production Enterprise while the new design solutions have almost halved the vibration level,” the statement reads.[...]

Source: https://theaviationist.com/2020/08/...msm-bear-bomber-performing-its-maiden-flight/

 

[Flyaway]

Very much the B-52 of the Russian Air Force especially with that 2040 end of service date.

 

[FighterJock]

Very much the B-52 of the Russian Air Force especially with that 2040 end of service date.

It will be very interesting as to what style of bomber the VKS replaces the Tu-95 with come 2040.

 

[GARGEAN]

Most probably it will appear much earlier (PAK DA). But fleet wide replacement is a long way.

 

[Josh_TN]

Also, like the B-52, the Tu-95 would probably be the last bomber type to be replaced. I can see Backfires and Blackjacks getting replaced by PAK DA long before anyone thinks of taking Bears with this upgrade out of service.

 

[yasotay]

The old maxim comes to mind: "If it works, don't … mesh with it."

 

[TomS]

If/when the PAK-DA does replace the Tu-95 bombers, what replaces the Tu-142s?

 

[kaiserbill]

I can see Backfires and Blackjacks getting replaced by PAK DA long before anyone thinks of taking Bears with this upgrade out of service.

Not so sure of that.
The Blackjack seems to have a long a long life ahead, by various reports and indications.
Not only have there been numerous reports of the Russians revamping and reinstalling the manufacturing capabilities of producing the large central titanium body of the fuselage/wing box, but they have been actively working on the upgrading of production facilities for the NK321 engine, as the below link explains once run through a translation. Reports indicate this engine (or a variant rather) might power the new bomber being designed, but also that there is the possibility that more Tu-160 airframes (Tu-160M2?) are to be produced.
Perhaps Flateric or some of our other Russian members would confirm?

Первая установочная партия двигателей НК-32 второго этапа поставлена для модернизированных Ту-160М

Объединенная двигателестроительная корпорация (ОДК, входит в госкорпорацию

naukatehnika.com

 

[Josh_TN]

IMO, there are too few airframes for Tu-160 to remain in service next to another modern bomber. I think the B-2 was going to be the first bomber the US replaces for the same reasons, except that the B-1s are spend and being drawn down to such small numbers that their replacement will probably be a requirement first. If you want my honest opinion, the PAK DA won't even enter service. But if it does, I do suspect the Bear will be the last thing replaced.

 

[GARGEAN]

If you want my honest opinion, the PAK DA won't even enter service.

Is there any base for that opinion, or just "feel"?

 

[haavarla]

There is the upgrade of Tu-95. That will ensure them a service decades from now, well the ones that get this latest upgrade that is.
And on top of this, they are slowly producing AND upgrading Tu-160M.

This means they are not in a hurry of getting the Pak-Da into service. But that said, i have no doubt it will happen.
At some point they need to get rid of the hoplessy Navy striker Tu-22M's.. they are something of a dissepointment as a modern Strategical platform by now.

 

[Josh_TN]

If you want my honest opinion, the PAK DA won't even enter service.

Is there any base for that opinion, or just "feel"?

I just a feeling. I think Russia's defense budget is struggling to recapitalize its legacy nuclear force and introduce brand new nuclear system types, all while modernizing its conventional forces across the board. I think projects with very long lead times might find that the money spigot has run out in the future. The US, specifically the US Navy, is similarly going to have a crushing budget problem in the future for new systems. Is there any kind of first flight/deployment time frame that has been published for PAK DA?

 

[Josh_TN]

There is the upgrade of Tu-95. That will ensure them a service decades from now, well the ones that get this latest upgrade that is.
And on top of this, they are slowly producing AND upgrading Tu-160M.

This means they are not in a hurry of getting the Pak-Da into service. But that said, i have no doubt it will happen.
At some point they need to get rid of the hoplessy Navy striker Tu-22M's.. they are something of a dissepointment as a modern Strategical platform by now.

There is also a modernization program for the Tu-22M3. And I don't understand why you consider it hopeless or a disappointment; I think it is generally considered a very capable platform in terms of range, speed, and payload. The fact that all three bomber types are undergoing modernization does indicate PAK DA is a long term plan.

 

[Evgeniy]

f/when the PAK-DA does replace the Tu-95 bombers, what replaces the Tu-142s?

Well, there is only one option, this is the old Tu-204P project.

Ðа базе ТÑ-204: РоÑÑÐ¸Ñ ÑоздаÑÑ Ð¿ÑоÑиволодоÑнÑй ÑÐ°Ð¼Ð¾Ð»ÐµÑ - ÐазеÑа.Ru

Ðлавное командование ÐÐФ планиÑÑÐµÑ ÑоздаÑÑ Ð¿ÑоÑиволодоÑнÑй ÑÐ°Ð¼Ð¾Ð»ÐµÑ Ð½Ð° базе паÑÑажиÑÑкого лайнеÑа ТÑ-204, ÑÑвеÑждаÑÑ Ð¡ÐÐ. ÐоеннÑй обозÑеваÑÐµÐ»Ñ «ÐазеÑÑ.Ru» ÐиÑаил ХодаÑенок...

www.gazeta.ru

Yes, it's like all the chatter now, but there is no other option.
And this option will be the most adequate.

 

[QuadroFX]

(c) UAC/ОАК

 

[haavarla]

There is the upgrade of Tu-95. That will ensure them a service decades from now, well the ones that get this latest upgrade that is.
And on top of this, they are slowly producing AND upgrading Tu-160M.

This means they are not in a hurry of getting the Pak-Da into service. But that said, i have no doubt it will happen.
At some point they need to get rid of the hoplessy Navy striker Tu-22M's.. they are something of a dissepointment as a modern Strategical platform by now.

There is also a modernization program for the Tu-22M3. And I don't understand why you consider it hopeless or a disappointment; I think it is generally considered a very capable platform in terms of range, speed, and payload. The fact that all three bomber types are undergoing modernization does indicate PAK DA is a long term plan.

If you take Tu-22M, and try to grade it. Then the ONLY capability that ONLY matters is the combo Weapon and platform!
Unless you get a hard-on seeing it do FAB-500 bombing run over Syria..
The Kh-22 and Tu-22M is a symbiosis. Now the world and time has long since moved on. The Kh-22 is long ago seen as antiq weapon. The airframe of Tu-22 was basicly build around the massive Kh-22, hense they are basicly one and the same.
As for mission range on Tu-22, no its not great by any stretch. Even now i think they have put back on the refueling probes due to end of START II treaty.

Now if they made accomondation for say Kinzal or Kh-101 on it.. i would had to change my opinion