Tu-144: busting myths

[DerAdlerIstGelandet]

Look, I like your different views on this, it can make for interesting discussion. I don't like your approach.

 

[Snautzer01]

Wrong! We kick out the people who argue their point in an arrogant and uncivil manner using insults and snide comments, and claim they are debating from an academic standpoint when they clearly aren't.

And we only do that after repeated warnings and suggestions to change their approach.

And we are sick of it NOW, and not "someday.

Relax. You putting out fire with gasoline.

Quote: academic standpoint when they clearly aren't. End quote.
I have not see you throw in any source, nor state why you think you can say this about a member giving sources. Nor why said member is so clearly wrong.
One can debate sources on merit. Or style.
I agree
But when challenging acedemic standpoint i sure wish a lot of sources.
Please endulge me.

 

[DerAdlerIstGelandet]

Relax. You putting out fire with gasoline.

Quote: academic standpoint when they clearly aren't. End quote.
I have not see you throw in any source, nor state why you think you can say this about a member giving sources. Nor why said member is so clearly wrong.
One can debate sources on merit. Or style.
I agree
But when challenging acedemic standpoint i sure wish a lot of sources.
Please endulge me.

1. I don't have to throw in a source when I'm not part of the debate.

2. Said user throwing out snide comments and insults in every post is not debating from an academic stand point.

3. The point of my post and why I said WRONG was that we are not kicking out members who are trying to argue their point of view. THAT IS A FACTUAL LIE. we kick them out for constant insults and breaking of forum rules they agreed to.

4. I hope you feel indulged. I'd rather you not question our every intent. We don't need our jobs made more difficult.

 

[DerAdlerIstGelandet]

When we receive PMs and reports of members detracting from conversations with constant personal attacks we tell all parties to knock it off, as we did in this particular case. Some members stop. Some don't. That is the case here.

 

[Simon Thomas]

Thrust figures:
"It is interesting to note that at the speed of the Concorde, which is 3.6 times 375 mph (1,350 mph), 1lb of thrust is 3.6 thrust horse power, and, thus, at 50,000 ft when the Concorde is cruising at Mach 2.05 and requiring a thrust of 10,000 lb from each engine, the power produced per engine is 36,000 hp, giving a total aircraft power of 144,000 thrust horse power from the four Olympus 593 engines"
(Not Much of an Engineer, Hooker, App II)

"The production airliner Concordes are propelled by four Olympus 593 Mk.610 engines and together they produce 152,200 lbs of thrust at take-off and 27,160lbs of thrust during the cruise at 60,000 feet."

Concorde Olympus 593

Concorde engines

www.heritageconcorde.com

This reinforces the earlier comment about L/D not being the whole story.
Would be great if there were an equivalent chart/figures/tables for the TU144 to allow real world comparison.

MTOW : 408,000 lb ~= 185 T

 

[OldGeezer]

Relax. You putting out fire with gasoline.

Not to change the subject too much, but back in the days when I made my living in the field of reducing combat aircraft vulnerability, I remember that one of the ways that was seriously proposed to reduce fuel tank ullage explosions was to put pumps in the tanks to spray a fine mist of fuel into the air spaces, which would make the fuel/air ratio much too rich to be ignited. So if not literally putting out the fires, at least preventing them from starting in the first place, using the fuel itself.

 

[bf109xxl]

one of the ways that was seriously proposed to reduce fuel tank ullage explosions was to put pumps in the tanks to spray a fine mist of fuel into the air spaces, which would make the fuel/air ratio much too rich to be ignited. So if not literally putting out the fires, at least preventing them from starting in the first place, using the fuel itself.

Weren't the tanks pressurized with inert gas? The fuel vapor pressure would still be limited by thermodynamics - it could not be higher than the saturated vapor pressure at a given temperature. In addition, diesel fuel, for example, could explode in unfilled tanks when hit by a shell, increasing the destruction - this is the experience of tank design in World War II, I think I posted statistics on the forum once.

 

[bf109xxl]

This reinforces the earlier comment about L/D not being the whole story.

I wrote about this already in post #11 - this parameter was more important for the Soviets than for the Anglo-French consortium, because the fuel efficiency of the Soviet engines was much lower. And with comparable (but still lower) fuel efficiency, the weight of the Soviet engines was higher than the Olympus one. The weight efficiency of the airframe was also higher for the Concorde. L/D_max is apparently the only efficiency parameter by which the Tu-144 was superior to the Concorde. The Soviets sacrificed (partly) aerodynamic efficiency on takeoff and landing modes for it.
Why L/D is the most important SST aerodynamic parameter can be understood from this book:

Would be great if there were an equivalent chart/figures/tables for the TU144 to allow real world comparison.

I doubt that similar graphs were published for the Tu-144. They are not included in the flight manual. But I will try to flip through the book from the starting post, it is the most comprehensive source on the Tu-144 that I know. Unfortunately, I have to order it again from the library - I didn't have the time or energy to scan it.

 

[bf109xxl]

On the effect of the wing planform on aerodynamic performance.

The story of the choice of the wing planform [chord/sweep variation along span] for the Tu-144 is didactic. It is known that the development of the Tu-144 began in the USSR in 1963. Britain and France began the development of the Concorde as a joint project a bit earlier. The wing of the Concorde prototype had a so-called sinusoidal shape of the leading edge with variable sweep angles of 76-58°. It seemed that such a complex shape, which was the result of a longtime research, apparently provides some unique aerodynamic properties. In particular, it was assumed that this shape is most favorable for the formation of vortex systems and allows to reach maximum nonlinear lift increments at high takeoff and landing angles of attack. A number of our specialists had a desire to copy this shape. However, it was shown by TsAGI [Central Aerohydrodynamic Institute] and OKB [Tupolev Experimental Design Bureau] that rounding of leading edge breaks has practically no impact on the lift properties, but worsens the longitudinal static stability at large angles of attack. In addition, the Concorde wing with a large cantilevers' sweep angle had low aspect ratio.
As it is known, the wing of the Tu-144 prototype has a single break of the leading edge, consisting of straight segments in the root extension and cantilever parts with different sweep angles. The series production Tu-144 had the sweep angle of the cantilevers' leading edge increased to 57° similar to the Concorde prototype, at the insistence of the same experts. However, when the data on the series production Concorde had been published in the press, it turned out that its "unique" shape of the leading edge was changed and the cantilevers' sweep angle was reduced down to 55°, as it was on the Tu-144 prototype. It should be noted that the use of the Tu-144 experience improved the aerodynamic performance of the Concorde in all flight modes.

My translation of a quote from the book "The truth about supersonic passenger airplanes" by V.Bliznyuk, L.Vasiliev, V.Vul, V.Klimov, A.Mironov, A.Tupolev, Y.Popov, A.Pukhov, G.Cheremukhin, Moscow, 2000. All the authors were direct participants in the design and/or testing of the Tu-144. I would appreciate comments on the translation.

Original text:

 

[OldGeezer]

Weren't the tanks pressurized with inert gas? The fuel vapor pressure would still be limited by thermodynamics - it could not be higher than the saturated vapor pressure at a given temperature. In addition, diesel fuel, for example, could explode in unfilled tanks when hit by a shell, increasing the destruction - this is the experience of tank design in World War II, I think I posted statistics on the forum once.

Planes with OBIGGS or its equivalent are inerted, but the one I was working on at the time (AV-8B) didn't have that or void-filling foam or anything else. We did a whole series of cost/weight/benefit tradeoff studies for ways that it could be made more survivable but none of them found any traction with the customer. It's actually surprisingly hard to get an explosive fuel/air mixture in aircraft ullage spaces, so much so that the test people developed a special "fuel" surrogate that was tailored to provide the required conditions more reliably. It was called JP-4S and if you're interested in such things, this is a China Lake report that talks about it (pages 4 and 6) - https://www.fire.tc.faa.gov/pdf/systems/NWC_TP_7129.pdf

 

[ThomasP]

I ran across manuals for the Concorde and Tu-144 on the Avialogs website. Went back and checked and Benoit has posted a significant number of the Concorde manuals.

He has also posted a number of Tu-144 manuals, but my Russian is not good enough for me to tell if any of them are pertinent to the current discussion.

For the Concorde he has posted 44 site pages of manuals - the pilot's manuals are listed on page 43.

"Avialogs: Aviation Library - Concorde"

Only 1 site page for the Tu-144, but I think they are all equipment oriented manuals - no pilot's manuals (I could be wrong).

"Avialogs: Aviation Library - Tu-144"

 

[bf109xxl]

I ran across manuals for the Concorde and Tu-144 on the Avialogs website. Went back and checked and Benoit has posted a significant number of the Concorde manuals.

He has also posted a number of Tu-144 manuals, but my Russian is not good enough for me to tell if any of them are pertinent to the current discussion.

For the Concorde he has posted 44 site pages of manuals - the pilot's manuals are listed on page 43.

"Avialogs: Aviation Library - Concorde"

Only 1 site page for the Tu-144, but I think they are all equipment oriented manuals - no pilot's manuals (I could be wrong).

"Avialogs: Aviation Library - Tu-144"

Thanks for the links!
I looked at the Tu-144 pdf-s, unfortunately they are mostly purely technical manuals. I had the Tu-144 flight manual in a more complete version with graphs and tables.

 

[ThomasP]

Hey bf109xxl,

If you ever get the time and it is not too inconvenient, please post what you have. I, and I am sure many others on the forum, would be interested.