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Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A340?

Posted: Thu May 16, 2019 3:40 pm
by phugoid1982
I was rather bored this morning thinking of the whole quads vs. twins debate and wondered why the Soviets never attempted to use the higher thrust Lotarev D18T engine used on the AN-124 and An-225 on the IL-96? I did some calculations matching the engine out climb performance of a twin engined IL-96 equipped with D-18Ts to a quad and calculated that for this to hold the max fuel capacity would have to be almost 1/3 of the original. The max range using Breguet range equation and taking into account the TSFC of the D-18T relative to the PS-90 would translate to a still air range of approximately ~3900 miles. This would still be respectable for a domestic aircraft and the on par with the early IL-62's which did transcons. Moreover, the maintenance costs would of course be signficantly reduced. I was thinking akin to the development of the A330 and A340 where the A340 was intended to be long range version to circumvent ETOPS and the A330 relegated so shorter segments, although this obviously changed with more powerful economical engines. Any thoughts appreciated.

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Thu May 16, 2019 3:49 pm
by anshabhi
After USSR collapse the economies collapsed/goals changed. Most of the Soviet civil aircraft were a spin off from military aircraft.

Further, the companies got split. For ex Antonov is based in Ukraine while most of its products were used in Russia and USSR sponsored the process as a whole.

There's a ton of material available online on collapse of Soviet aerospace industry along with USSR

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Thu May 16, 2019 3:54 pm
by dcajet
Probably a good dose of reality as well. In the 90s Russia was broke and any market for such a plane had evaporated. Even today, with Russia in a much stronger position, its struggles to sell its designs beyond its captive markets.

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Thu May 16, 2019 4:32 pm
by Slash787
And Im still waiting for the Il-96-400 to fly and hopefully be delivered to Cubana in this lifetime.

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Thu May 16, 2019 5:18 pm
by luckyone
anshabhi wrote:
After USSR collapse the economies collapsed/goals changed. Most of the Soviet civil aircraft were a spin off from military aircraft.

Further, the companies got split. For ex Antonov is based in Ukraine while most of its products were used in Russia and USSR sponsored the process as a whole.

There's a ton of material available online on collapse of Soviet aerospace industry along with USSR

That's not really the case for most of the post-war aircraft, particularly Ilyushin. The last jetliner to be produced in big numbers that was derived from a military aircraft was the Tu-134. The Tu-154, IL-62, and 86 were all purposely developed for civilian purposes.

To answer the question, at the time I would imagine the cost of development for the wing would have been beyond the means of the time.

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Thu May 16, 2019 5:30 pm
by drdisque
My guess is that the D-18T was designed for thrust at all cost and had poor fuel economy by modern standards.

Progress was also possibly not interested in building many more of them. They've only built 188 to date.

End result, economy may not have been better than the IL-96M.

Also, there may have been packaging issues as the D-18T was designed for high wing applications and the IL-96 sits relatively low.

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Thu May 16, 2019 8:43 pm
by workhorse
Also, you have to take into account that in the 90's Russia, the Il-96 was simply too big.

What was the main long haul aircraft of Aeroflot at that time? The A310. Only in the 2000's they started switching to 330s and 77Ws.

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Thu May 16, 2019 9:24 pm
by ewt340
They don't have enough customers.

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Thu May 16, 2019 10:00 pm
by ewt340
Also, IL-96 is too big for domestic operations.

The bigger question is, why don't they make a copy of B737 instead?

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Thu May 16, 2019 10:05 pm
by Pudelhund
Slash787 wrote:
And Im still waiting for the Il-96-400 to fly and hopefully be delivered to Cubana in this lifetime.


Surely you mean the modernized M version? The -400 already exists and is flying, same with the -400T which is the freighter variant.

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Thu May 16, 2019 10:14 pm
by PSAatSAN4Ever
Spare parts.

Servicing and repair of the aircraft.

Customer support.

Soviet/Russian aircraft - while fabulous aircraft in their own right - simply don't have the sales support for airlines the way that Boeing, Airbus, Embraer, Bombardier, and all others do/did.

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Thu May 16, 2019 10:30 pm
by Slash787
Pudelhund wrote:
Slash787 wrote:
And Im still waiting for the Il-96-400 to fly and hopefully be delivered to Cubana in this lifetime.


Surely you mean the modernized M version? The -400 already exists and is flying, same with the -400T which is the freighter variant.


I know, I was talking about the M version or whatever new version Cubana has on order since god knows how many years now.

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Thu May 16, 2019 10:36 pm
by PlymSpotter
The Il-96 was based on the Il-86, meaning the entire architecture was orientated towards it being a quad jet.

The A330/340 meanwhile was designed to be a dual quad / twin jet from the outset.

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Thu May 16, 2019 11:37 pm
by Phosphorus
USSR was burned once by inability to fly Tu-104 transatlantic (something to do with international rules to have diversion field handy, unless you have three engines or more). They were not about to forget that easily.
Now Il-96 and its powerplant were a result of many political and design compromises. Sufficies to say that PS-90 on Il-96 was a result of a project to standardise engine pool between Il-96 and Tu-204

A leap of faith, required to redesign Il-96 around two engines, built to maximize thrust per military requirements (and all else be damned), would be massive.

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Fri May 17, 2019 12:14 am
by leleko747
Pudelhund wrote:
Slash787 wrote:
And Im still waiting for the Il-96-400 to fly and hopefully be delivered to Cubana in this lifetime.


Surely you mean the modernized M version? The -400 already exists and is flying, same with the -400T which is the freighter variant.



Just a little update to your info: as far as I know, the only 400s flying are now in service for the Russian Government. These were ex-Polet Flight, 400T version, and were converted to passenger (yes, converted from cargo to pax!!!) interior.

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Fri May 17, 2019 12:59 pm
by phugoid1982
Thanks for all the replies. To clarify I was thinking the twin engined IL-96 being developed simultaneously with the long range variant in the mid 80's when the Soviets where starting to pay attention to efficiency before the collapse and subsequent collapse of the domestic air travel market. The D-18T has a 25% higher TSFC but again the reduction in maintenance is what I was focused on. Also, I know the PS-90 was notoriously unreliable and I'm wondering how the D-18T compares in that respect? Also, even though the Il-96 was based on the Il-96 the wing is completely new supercritical wing so it could've been designed to be a twin, although as was pointed out the landing gear would've had probably had to have been designed to be taller to accomodate the engine.

Funny enough, I stumbled upon this article in Flight Global about UAC studying a twin re-engined with the PD-35 under development to breath some life into the program.

https://www.flightglobal.com/news/artic ... 96-445788/

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Fri May 17, 2019 1:06 pm
by Armadillo1
ewt340 wrote:
Also, IL-96 is too big for domestic operations.

The bigger question is, why don't they make a copy of B737 instead?

Tu-204 was here, 734 range enough for this side from Ural only. also, its funny to see question about 737classic copy with A320 in flight

Phosphorus wrote:
They were not about to forget that easily.

wel well, nobody heard about IL-62

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Fri May 17, 2019 6:10 pm
by Ty134A
First of all, an ILW or IL9 is not an 330/340 fuselage. It is only marginally below the diameter of a 777, making it a rather wide bodied plane, not allowing for engines in the thrust area where the D-18 is situated. Three D-18 engines would work, two wouldn't. And there was no need for it, fuel was not a factor, nor other economical aspects that today do count. They had IL6 for long haul, and began flying the IL9. Up to 5000km they had ILW and TU5, with the T20 on the way. And with YK2 there was a turbofan jet with actually a D-18 family engine aboard, the D-36. This engine ist still in use today as D-436 with A81 and Beriev sea planes. Soviet SU most likely favoured the D-18 for strategic transportation on the A4F. With new noise regulations and emission standards, it basically ment that the SU was left with only a hand ful of engines, the D-30KU-154 had also it's clock ticking. So there were the PS-90A and the D-36. They had the ILW and they had the PS-90, so they made something out of it. The reason for the IL9 being so stubby is, by the way, the lack of adequate soviet engines. And sure nobody thought of a 346 like ILW with four D-18... So they had to shorten the fuselage, keep the diameter and use 4 PS-90.

I remember that SU IL9 had an CASM on par with their 763. But remembering that some airlines preferred the thirsty ILW over a low numbered IL9 (spares!!!) it somewhat shows that engines were not the main issue of this airframe. Neither was safety an issue. Only one ILW very unfortunately crashed (after maintenance) and one IL9 burned down while parked. Also T20 performed extremely well safety wise, and all late Soviet frames were really good, solid/safe aircraft, but with the usual downfalls. I also preferred classic Soviet T5M over the Russian built ones, so did pilots. Same goes for ILW... Yet thair safety statistics speak for them, and deserve a certain amount of respect, considering what Boeing came up with lately...

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Sat May 18, 2019 8:45 am
by Phosphorus
Armadillo1 wrote:
Phosphorus wrote:
They were not about to forget that easily.

wel well, nobody heard about IL-62

Well, Il-62 was a quad. Unless you are trying to convey some other point, I guess it meets "three or more engines" requirement.

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Sat May 18, 2019 2:30 pm
by exFWAOONW
Don’t twins require a larger rudder to compensate if they loose an engine?

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Sat May 18, 2019 5:57 pm
by Ty134A
exFWAOONW wrote:
Don’t twins require a larger rudder to compensate if they loose an engine?


Depends how long they are! Ask a 74L about large rudders...

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Sat May 18, 2019 6:26 pm
by VSMUT
Slash787 wrote:
Pudelhund wrote:
Slash787 wrote:
And Im still waiting for the Il-96-400 to fly and hopefully be delivered to Cubana in this lifetime.


Surely you mean the modernized M version? The -400 already exists and is flying, same with the -400T which is the freighter variant.


I know, I was talking about the M version or whatever new version Cubana has on order since god knows how many years now.


FYI, the original Il-96 stretch is just Il-96M, no -400. The freighter was the Il-96T. The Il-96-400 is the new Russianized stretch that has yet to fly, and has been ordered by Cubana. The Il-96-400M is an even newer project which also hasn't flown yet, probably mostly for the Russian MOD.

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Sat May 18, 2019 8:50 pm
by Phosphorus
VSMUT wrote:
Slash787 wrote:
Pudelhund wrote:

Surely you mean the modernized M version? The -400 already exists and is flying, same with the -400T which is the freighter variant.


I know, I was talking about the M version or whatever new version Cubana has on order since god knows how many years now.


FYI, the original Il-96 stretch is just Il-96M, no -400. The freighter was the Il-96T. The Il-96-400 is the new Russianized stretch that has yet to fly, and has been ordered by Cubana. The Il-96-400M is an even newer project which also hasn't flown yet, probably mostly for the Russian MOD.


Then what am I looking at here, airborne in 2009 (not the only photo of the type in the database, I would assume):

https://www.airliners.net/photo/Polet-A ... 0T/1574277

Does this airframe meet your definition of Il-96-400 ?

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Sat May 18, 2019 9:16 pm
by VSMUT
Phosphorus wrote:
VSMUT wrote:
Slash787 wrote:

I know, I was talking about the M version or whatever new version Cubana has on order since god knows how many years now.


FYI, the original Il-96 stretch is just Il-96M, no -400. The freighter was the Il-96T. The Il-96-400 is the new Russianized stretch that has yet to fly, and has been ordered by Cubana. The Il-96-400M is an even newer project which also hasn't flown yet, probably mostly for the Russian MOD.


Then what am I looking at here, airborne in 2009 (not the only photo of the type in the database, I would assume):

https://www.airliners.net/photo/Polet-A ... 0T/1574277

Does this airframe meet your definition of Il-96-400 ?


The Polet freighters would simply be Il-96T.

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Sun May 19, 2019 7:35 am
by Phosphorus
VSMUT wrote:
The Polet freighters would simply be Il-96T.


That would be before conversion, while still equipped with PW engines.

After conversion to PS-90 in the last decade, at least one frame got both new factory number, and designation Il-96-400.
Another frame was directly built as Il-96-400T late last decade.

So the "new" airplane in the works is the Il-96-400M, otherwise there was a to convert an existing Il-96-400T into a pax version for Cubana (frame RA-96103). Not sure what came out of that, but that's hardly a new plane, is it?

Re: Why did the Soviets never try making a domestic twin IL-96 using the Lotarev D-18T engine similar to the A330 and A3

Posted: Sun May 19, 2019 1:22 pm
by SR380
Phosphorus wrote:
VSMUT wrote:
The Polet freighters would simply be Il-96T.


That would be before conversion, while still equipped with PW engines.

After conversion to PS-90 in the last decade, at least one frame got both new factory number, and designation Il-96-400.
Another frame was directly built as Il-96-400T late last decade.

So the "new" airplane in the works is the Il-96-400M, otherwise there was a to convert an existing Il-96-400T into a pax version for Cubana (frame RA-96103). Not sure what came out of that, but that's hardly a new plane, is it?


Last August the aircraft was photographed in VASO with many Il-96. I haven't heard much since then.