Russian Aircraft Structures Design

[Volume]

Hi everyone,

looking at the wreakage of the Tu 154 crashed last week, after torn apart by an explosion in more than 30.000 feet, I wounder about differences between ´western´ and ´eastern´ structural design.
http://wwwi.reuters.com/images/2004-08-27T080700Z_01_DEO728854_RTRDEOP_2_PICTURE0.jpg
Have you ever seen the wreakage of a ´western´ airplane beeing in such big pieces after a severe crash ?
The flaps and slats are still attached to the wing, both wings are still joined together, most of the fairings are still present.
It was very impressive to see the differences for the south german/swiss midair last year, while the Tupolev wreakage consisted of large parts (front fuselage, tail section, wing ...) mainly beeing in one piece, the Boeing wreakage consisted of pices smaller than 1 meter, totally torn apart.

Is there a difference is structural design ? Are the Russians using more ductile materials ? Are they building much stronger ? Do they use different type of fasteners ?

[Wino]

Has more to do with the nature of the impact than anything else.

Hit the ground hard enough and even a brick will disintegrate.

Russian structures are a little different in the certification (for example required to survive a doublet of the type that brought down the Airbus that was American Airlines 587)

But the observations that you have made in the accident have nothing to do with the strength of the aircraft, just the nature of the impact.

Cheers
Wino

[Genghis the Engineer]

Around the end of the cold war I worked briefly in a Russian design bureau, and a thoroughly educational experience it was - the Russians train superb Engineers, arguably a training system far better than the British, European or American models.

However, in general, they don't design significantly different aeroplanes, just reach the design by a different route. They are far more evolutionary, and less revolutionary than we're used to in "the West". What I mean by that, is that whilst a Western trained Engineer will start with a blank sheet of paper and design exactly the aeroplane they want - a Russian will start with an existing design, and modify it to get what they're after. The result is generally that over "here" we achieve more radical designs quickly - and have more problems with them, whilst the Russians achieve less radical designs - which work better straight off.

Which doesn't answer the question really. There are differences between Western (FAR based) and Eastern (soviet based) airworthiness requirements - in general the Eastern approach tends to incorporate much higher structural reserve factors. However, in this instance frankly it's irrelevant - aerial collision, or in-flight break-up loads are so great that the reserve factors aren't a player.

I've seen Western flying machines of the same type either disintegrated into tiny bits, or come down almost intact. It's very much a function of the accident.

So, from a slightly different perspective, I agree completely with Wino.

G

[Boss Raptor]

Not a technical comment as such - but i have considerable experience of operating particularly the TU154 and being in close intimate proximity to the aircraft and its' systems - in comparison to its' western equivalents it is build like the perverbial battleship with what appear to be thicker skins, more substancial structure and lots more rivets instead of bonding - it is big, chunky, takes a lot of damage and is relatively easy to repair

[lomapaseo]

Agree with comments above

As soon as I saw that photo I was suspect of no tail and no nose when it struck the ground with little forward velocity.

[MkVIII]

Russian aircraft are built like the proverbial brick out-house. STRONG, ever-lasting. BUT, that of course has it's downside - extra weight, meaning greater FBO's, lower freight uplift (depends on the aircraft naturally!). Russian designs may seem cruder, and less refined, but work darned well.

As Ghengis said, Russians tend to reverse engineer existing designs, and adapt as required - ever notice how many of their airliners look like existing western counterparts - Tu144 (concorde), 154 (727), 334 (F28 / 100), 204 and 214 (757), 134 (Dc-9 ish), Il62 (VC-10) and Il86/96 (Airbus) are prime examples!

They may not have the refinement of Western designs, but NEVER denegrate them based on structural strenght.

Kind of remind me of good old Douglas aircraft in fact!

[Genghis the Engineer]

I think it's always a little unfair to acuse the Tu-144 of being a Concorde clone - yes it's superficially very similar, but it did fly first.

G

[alexban]

I did fly some russian build airplanes.They are tough,can take a lot of dammage.The An24 ,for ex, has a MTOW of about 21 T (if my memory is corect) and could have easily take off with 3-4 T more. We had one entering in bad weather and getting out like a swaitzer,full of holes in the wings and still flying like new.the structure was made of bars like railroad tracks.
There are indeed,made like battleships. Most of them,actually,were designed to be easily used as military planes (transport-the AN,bombers-tu 154,144)
Most can land on grass rwys,even the mighty An124.
They are very good designers,and are still making a lot of nice new planes.

[MkVIII]

I think it's always a little unfair to acuse the Tu-144 of being a Concorde clone - yes it's superficially very similar, but it did fly first.

G



Yes, but the Soviets DID base their design on the Concorde, NOT the other way around.

The Russians rushed the 144 into flying, and hence, beat the Anglo-French at the game.

How many revenue flights did the -144 ever do? ANY?

Paris certainly ended it's career - why? Was their an inherant design flaw that the Soviets could NOT overcome, so merely shelved it? I know the second -144 is being rejuvenated to fly, I think for NASA, and needed SIGNIFICANT upgrades, not merely in the avionics suite.

[Genghis the Engineer]

Yes, but the Soviets DID base their design on the Concorde, NOT the other way around.

References please?


How many revenue flights did the -144 ever do? ANY?
Revenue wasn't an issue in the Soviet era, but it did fly extensively within the USSR before things went horribly wrong.


I'm not saying the Tu-144 was a successful aeroplane, in the long run it wasn't. And almost certainly it was built because somebody in the Kremlin was determined that if the Yanks and Brits were building a supersonic airliner the USSR should too. But, my belief (having talked to people who worked on it, and had a good poke around one in a museum over there) is that it was substantially an original design.

G

[Hay Ewe]

I did also hear about the TU-144 that it used to fly to Cuba.

Now, I only heard this one time so really am not sure if it is right, I expect that there are people out there who would now if

a) it ever did
B) how often / was it a one off.

What I also heard at the same time was that they had to ship replacement engines to Cuba for it because by the time it got there the engines were so done in they needed over haul and wouldnt have got back to the mother land.

Like I said, only heard it once so dunno if its true.

Hay Ewe - is that another sonic boom?

[bigflyingrob]

As I recall there was a program on a while back that said the U 144 mk 1 was a Russian design but the MK2 was a concorde copy as a spy had given them a copy of the drawings. Still with TV and the security services involved tha chances of the truth being out there are about the same as the X files!

[MkVIII]

No, that is not merely conspiracy theorists at work. The Soviets readily admit that the Tu-144 was in fact based around the PRELIMINARY design work done by the Anglo-French, and drawings "obtained" from the French.

If you examine early Concorde design studies, you will note a definite resemblence, even in the wing planform, and engine nacelle arrangement. On the Concorde, after MANY different flying testbeds were flown with different wing plan forms and shapes, they chose the more elegant (and harder to manufacture) ogive delta we all kow so well.

The Russians adapted and adopted one of the earlier wing planform designs, and the earlier nacelle arrangement.

For those interested, I CAN go through all my collection of Air Pictorial magazines from that era to show the progression of the Concorde design - glad I kept them all (probably worth some dosh too!)

Russian designers took a LONG time to finally arrive at significantly independant design styles. Stalin INSISTED that post-war fighters DID NOT embody MANY Me-262 design features - any that DID were doomed to fail, even if they were significantly superior to the opposition. Fighter designers at least seemingly broke the mold of Russian design, whereas the airliner / transport designers liked to imitate...

[Notso Fantastic]

I was informed the Concorde was the only supersonic airliner that could supercruise- cruise supersonically on jet thrust without afterburner. The TU144 needed constant reheat to maintain supersonic cruise, with all the fuel gulping that implies. So....carry any sort of payload Moscow-Havana? Nahhh! Fuel tankage to do it subsonic across Europe then supersonic with a payload of 2 people? No chance. If it ever did it, it would have had to be subsonic with hardly any payload.
I seem to recall it was only ever used on one internal service (Alma Ater or somewhere obscure?) for a while before being quietly withdrawn to await NASA testing.

[Boss Raptor]

Flew post only - no revenue pax. - MOW Almaty for a few years

[cringe]

It appears that the Tu-144 was used in passenger service for a short period - until the second crash:

The Tu-144S went into service on December 26, 1975, flying mail and freight between Moscow and Alma-Ata in preparation for passenger services, which commenced in November 1977 and ran a semi-scheduled service until the first Tu-144D experienced an in-flight failure during a pre-delivery test flight, and crash-landed with crew fatalities on May 23, 1978. The Aeroflot flight on June 1, 1978 would be the Tu-144's 55th and last scheduled passenger service.

A scheduled Aeroflot freight-only service recommenced using the new production variant Tu-144D aircraft on 23 June 1979, including longer routes from Moscow to Khabarovsk made possible by the more efficient RD-36-51 engines used in the Tu-144D version. Including the 55 passenger flights, there were 102 scheduled Aeroflot flights before retirement of commercial services.

It is known that Aeroflot still continued to fly the Tu-144D after the official end of service, with some additional non-scheduled flights through the 1980s. One last report showed that it was used on a flight from the Crimea to Kiev in 1987.
http://www.wordiq.com/definition/Tupolev_Tu-144

Edited to add a link to a proposed Tu-144D routemap that envisioned Havana, Tokyo and New York flights:

http://www.tupolev.ru/English/Picture.asp?PubID=2390

[steamchicken]

Some comparison figures between the Tu144 and Concorde appear on that map - I don't read Russian, what do they refer to? (the ones that have a + or - sign)

The Tu-144S model had NK-144 turbofan engines, whereas the later Tu-144D model featured more powerful RD-36-51 engines with better fuel efficiency (particularly during supercruise, not requiring afterburner) and longer range.

But...It should be noted that the original Tu-144 and Tu-144S equipped with the NK-144 turbofan engines could not cruise at Mach 2 without the afterburner on

[cringe]

My Cyrillic isn't very good, but I think that one comparison between the Tu-144D and Concorde relates to passenger capacity (150 vs 108) and the last two columns might contain estimates on route profitability.

[steamchicken]

In that case they all seem Sovietly favourable...

[Volume]

On the first view most of the soviet numbers look favorable.
The 144 could carry up to 150 pax in a 5 abrest seating, while the concorde could carry up to 108 in a 4 abrest configuration.
The later 144D-Version with improved engines claims to have about the same fuel capacity as Concorde (95t) and about the same range (6500 km), so they should run on comparable MPG but the 144 could carry 40% more pax.
Anyway these figures may be at different speed, and the engine TBO of the russians might have well outrun fuel costs.
Obviously both failed to provide profitable passenger service after the 70s oil price rise.
The 2000 paris crash would most probably not have happened with the 144, as the undercariage is placed in the engines nacelle and the tire debris trajectory does not affect any fuel tanks. Additionally the Vmc is much lower for the 144 using the canard in low speed configuration allowing the elevons to be used as a flap and increase overall lift. (looking at the canard, it is a REAL high lift device : double slottet slats and triple slottet flaps ! It must provide a C l max of 3 or even more) The engines closer to the centerline are also helpful if you loose two on the same side.

Unfortunately facts and myth mix for both planes and hard facts are not available to most of us folks.