PRC Tu-4 w/ WJ-6(?) AI-20 turbo props performance Q

[frank]

I've been reading in various sources recently about the PRC Tu-4s modded with the turboprops. We all, I guess, know about the drone carrier & AWACS & I've read some indication that the conversion goes back to the '70s for the standard bomber version, I guess the drone carrier being closest to that. However, I've not found any performance data & I'm curious as to that. I don't know how the weights of the piston engines compare to these turboprops, but they are about twice the power of the recips & appear a cleaner (less drag) installation combined with the additional exhaust thrust, surely the a/c would have been a screamer, not to mention climbing like a bat out of Hades along with greatly reduced ground roll & probably no payload weight limit. Anyone ever seen or heard what its performance was? Or, any of you engineering types have a thought? My limited knowledge & guesstimate of turboprop mods in general it oughta be able to hit about 500 MPH, but I also don't know the airframe limitations, in addition to climbing like that aforementioned bat & other guesstimates. Thanks.

 

[Apophenia]

Frank,

I suspect that you're right about a 500 mph top speed. After all, the corpulent An-12 Cub can hit 482 mph (777 km/h) on similar engines.

The original Tu-4 is a much heavier aircraft [Tu-4 empty weight: 77,594 lb / 35,270 kg vs An-12 62,000 lb / 28,000 kg]. But considerable weight loss must have been accomplished just by removing the gun turrets, bomb racks, etc.

You asked about comparative engine weights. Empty weight of the original ASh-73TK radial was 2,987 lbs / 1,355 kg. Empty weight for a AI-20M turboprop (or Zhuzhou Wojiang-6 equivalent *) is 2,376 lbs / 1,080 kg.

So, reckon on a further 2,444 lbs / 1,110 kg in engine weight saved. That's 4 x 611 lbs / 277 kg difference between the empty weights of ASh-73TK and AI-20/WJ6.

[* The Kong Jiang-1 AEWC may well have Zhuzhou Wojiang-6s with BPF props. But, I think we can assume that earlier Tu-4 conversions had AI-20Ks or AI-20Ms with Stupino props. In any case, the dry weight for the WJ6 should be identical to an AI-20.]

 

[borovik]

1)-2) - Tu-4 (AI-20M)
3) – “Aircraft – 94” Tu-4 (TV-2)
4) – “Aircraft – 94” Tu-4 (TV-4)
Sources: “AviO’4”
“Aviation Cosmonautics #17
V.Rigmand "Strategic twins"

 

[Apophenia]

Nice! Thank you, Borovik.

Do you have any information on the 1951 flight testing of TV-2s on the Tu-4? Was the TV-4 another Isotov design?

 

[borovik]

"Do you have any information on the 1951 flight testing of TV-2s on the Tu-4?"
The TV-2 at that time had, as per its trials:
5163 shp (taking off mode)
3740 shp (cruise mode)
dry weight (whole assembly) 1700 kg
The Tu-4 performance with TV-2 could be improved at 15-20% only, which
wasn't enough, so they stopped further works.
"Was the TV-4 another Isotov design?"

TV-4 (original designation of VK-2) Single-shaft axial turboprop developed at GAZ-117 under Klimov 47 to termination 1952; 8-stage, 3,357/3,580 kW at 9,000 rpm

Sergei P. Izotov (1917-1983) - chief designer of air-engines.
A disciple and first substitute V.Ya.Klimov’s……With 1962 more than 20
years stayed at the head of "V.Ya. Klimov" factory .
As per my opinion, it is about the same engine. :-\

 

[Apophenia]

Excellent, many thanks Borovik!

"Do you have any information on the 1951 flight testing of TV-2s on the Tu-4?"
The TV-2 at that time had, as per its trials:
5163 shp (taking off mode)
3740 shp (cruise mode)
dry weight (whole assembly) 1700 kg
The Tu-4 performance with TV-2 could be improved at 15-20% only, which
wasn't enough, so they stopped further works.

And, I think, there is the answer to Frank's original question.

 

[famvburg]

I just read in a Tu-4 book that the Tu-4 that was tested with the TV-2 engines had contra-props. I haven’t seen any pics, but if it had contra-props, wouldn’t they be shown in drawings, as they are on the TV-4 powered one? I found drawings of the Jumo 022 showing contra-props, but that’s it. Also, any idea where the exhausts came out on the TV-2 version?

 

[ucon]

Some pix of Tu-4LL

 

[ucon]

and two more from many LL on Tu-4

 

[Vahe Demirjian]

I've been reading in various sources recently about the PRC Tu-4s modded with the turboprops. We all, I guess, know about the drone carrier & AWACS & I've read some indication that the conversion goes back to the '70s for the standard bomber version, I guess the drone carrier being closest to that. However, I've not found any performance data & I'm curious as to that. I don't know how the weights of the piston engines compare to these turboprops, but they are about twice the power of the recips & appear a cleaner (less drag) installation combined with the additional exhaust thrust, surely the a/c would have been a screamer, not to mention climbing like a bat out of Hades along with greatly reduced ground roll & probably no payload weight limit. Anyone ever seen or heard what its performance was? Or, any of you engineering types have a thought? My limited knowledge & guesstimate of turboprop mods in general it oughta be able to hit about 500 MPH, but I also don't know the airframe limitations, in addition to climbing like that aforementioned bat & other guesstimates. Thanks.

The KJ-1 (AEW derivative of the Tu-4) with had a top speed of 346 mph (558 km/h).

Links:

Shaanxi KJ-1 – Wikipedia, wolna encyklopedia

pl.wikipedia.org

KJ-1 — Википедия

ru.wikipedia.org

 

[Archibald]

When you think about it, the B-29 extended family is pretty unbelievable - B-50, Stratocruiser, KC-97, (Super) Guppy, Tu-4 (and Tu-85), and Chinese AWACS. It boggles the mind.

 

[NUSNA_Moebius]

Are the Tu-16 and Tu-95 completely void of B-29 DNA? Figured there would be some of the same fuselage strutural design elements.

 

[Vahe Demirjian]

Are the Tu-16 and Tu-95 completely void of B-29 DNA? Figured there would be some of the same fuselage strutural design elements.

The Tu-95 was a descendant of the Tu-85, itself derived from the B-29 and Tu-4, differing from the Tu-85 in that is replaced piston power with turboprop engines (derived from the Junkers Jumo 022 turboprop, blueprints of which fell into Soviet hands after World War II). The Tu-16 had a totally different design philosophy than the Tu-4, because the turbojets were buried in the wing roots like the wartime Junkers EF 132 jet bomber project and the nose section was borrowed from the earlier '86' design, itself a scaled-up version of the Tupolev '82' (Tu-22) prototype swept-wing jet bomber.

 

[iverson]

Are the Tu-16 and Tu-95 completely void of B-29 DNA? Figured there would be some of the same fuselage strutural design elements.

The Tu-95 was a descendant of the Tu-85, itself derived from the B-29 and Tu-4, differing from the Tu-85 in that is replaced piston power with turboprop engines (derived from the Junkers Jumo 022 turboprop, blueprints of which fell into Soviet hands after World War II). The Tu-16 had a totally different design philosophy than the Tu-4, because the turbojets were buried in the wing roots like the wartime Junkers EF 132 jet bomber project and the nose section was borrowed from the earlier '86' design, itself a scaled-up version of the Tupolev '82' (Tu-22) prototype swept-wing jet bomber.

The Tu-16 inherited its gun turrets from the B-29/Tu-4.