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Re: Su-35. How the hell it did that?

Unread postPosted: 17 Nov 2019, 13:56
by ricnunes
ovod wrote:
Patriot wrote:9.4t fuel is for two seat Flankers like Su-27UB & Su-30.
Wikipedia claims the Su-35 fuel capacity to be 11,5t (25,400lb) which is basically roughly the equivalent 4x F-16 or 2x F-15C and it has ~25% more fuel than Raptor.
Quite impressive.


I suspect Wikipedia is wrong with 11.5 tonnes - 10 tonnes would be more like it - you would need a source for it.


Well, I found this source (airforce-technology.com) which IMO is more reliable than wikipedia:
https://www.airforce-technology.com/projects/su-35/

Where you can read the following:
The total fuel capacity is 14,350l. In order to increase the unrefuelled range and endurance compared to earlier models the Su-35 incorporates additional tailfin and fin-root tanks. The fuel tanks are of aluminium lithium construction and are located in the wings, fuselage and in the square-tip twin tailfins. The unrefuelled range on internal fuel is 1,580km.


14,350l of jet fuel seems indeed to be something around 25,400lb of fuel or 11,500kg previously mentioned.

Now the question is:
- Does that "total fuel capacity" value refers to internal fuel only or internal plus external fuel tanks?

Re: Su-35. How the hell it did that?

Unread postPosted: 17 Nov 2019, 15:20
by zhangmdev
I don't remember seeing a photo of a Su-27 carrying external tanks. That must be a rare occurrence.

Re: Su-35. How the hell it did that?

Unread postPosted: 17 Nov 2019, 17:36
by sprstdlyscottsmn
The 27 can't only the 35 does

Re: Su-35. How the hell it did that?

Unread postPosted: 17 Nov 2019, 17:44
by Patriot
Only been able to find photos of Su-34 with centerline tank.
The world wide web sources claim that Su-27SMK can carry 2000litres tank under each wing. Although I never ever seen a Flanker in such configuration.

Image
Image

Re: Su-35. How the hell it did that?

Unread postPosted: 17 Nov 2019, 20:44
by swiss
Thy Milosh. Only 6g. :shock: 56% is only 5.2 tonnes of fuel. 2000 lbs less then the F-15C

ricnunes wrote:
ovod wrote:
Patriot wrote:9.4t fuel is for two seat Flankers like Su-27UB & Su-30.
Wikipedia claims the Su-35 fuel capacity to be 11,5t (25,400lb) which is basically roughly the equivalent 4x F-16 or 2x F-15C and it has ~25% more fuel than Raptor.
Quite impressive.


I suspect Wikipedia is wrong with 11.5 tonnes - 10 tonnes would be more like it - you would need a source for it.


Well, I found this source (airforce-technology.com) which IMO is more reliable than wikipedia:
https://www.airforce-technology.com/projects/su-35/

Where you can read the following:
The total fuel capacity is 14,350l. In order to increase the unrefuelled range and endurance compared to earlier models the Su-35 incorporates additional tailfin and fin-root tanks. The fuel tanks are of aluminium lithium construction and are located in the wings, fuselage and in the square-tip twin tailfins. The unrefuelled range on internal fuel is 1,580km.


14,350l of jet fuel seems indeed to be something around 25,400lb of fuel or 11,500kg previously mentioned.

Now the question is:
- Does that "total fuel capacity" value refers to internal fuel only or internal plus external fuel tanks?


According to the UAC the Su-35 has 11.3 tonnes of internal fuel.

https://www.uacrussia.ru/en/aircraft/li ... n-features

The structure (including major elements of the fuselage, wing, stabilizers, and landing gear) of the Su-35’s airframe was reinforced, enabling an increase in the airplane’s maximum takeoff weight. That made it possible to significantly increase the amount of fuel on board (as the Su-35 carries 11.3 tons of fuel in its integral fuel tanks while the Su-27 carries just 9.4). Along with this, the fighter is equipped with a flight refueling system and can carry drop tanks with a 2,000 liter capacity each. The payload remained the same as in the Su-27: 8 tons. The number of hardpoints grew from 10 to 12.

Re: Su-35. How the hell it did that?

Unread postPosted: 17 Nov 2019, 21:08
by madrat
The centerline tank is probably unique to Su-34. Using one on Su-30SM would marginalize the Su-34 role. Su-27 and Su-35 have pretty extreme fuel fraction and can refuel in the air, so not much call for EFT. They already need TVC to log those big planes as it is, the EFTs would restrict maneuvering with TVC to some extent.

Re: Su-35. How the hell it did that?

Unread postPosted: 17 Nov 2019, 21:29
by milosh
swiss wrote:Thy Milosh. Only 6g. :shock: 56% is only 5.2 tonnes of fuel. 2000 lbs less then the F-15C


I think they wanted better range then F-15A not F-15C, because F-15A was actual when requirements for Su-27 were created or to be precise for Sukhoi T-10. Su-27 is Sukhoi T-10S radical redesign.

Re: Su-35. How the hell it did that?

Unread postPosted: 17 Nov 2019, 21:55
by ricnunes
swiss wrote:According to the UAC the Su-35 has 11.3 tonnes of internal fuel.

https://www.uacrussia.ru/en/aircraft/li ... n-features

The structure (including major elements of the fuselage, wing, stabilizers, and landing gear) of the Su-35’s airframe was reinforced, enabling an increase in the airplane’s maximum takeoff weight. That made it possible to significantly increase the amount of fuel on board (as the Su-35 carries 11.3 tons of fuel in its integral fuel tanks while the Su-27 carries just 9.4). Along with this, the fighter is equipped with a flight refueling system and can carry drop tanks with a 2,000 liter capacity each. The payload remained the same as in the Su-27: 8 tons. The number of hardpoints grew from 10 to 12.



So that means that the wikipedia entry on the Su-35 and its internal fuel information isn't far off (it erred by 200kg), thanks swiss!

Re: Su-35. How the hell it did that?

Unread postPosted: 18 Nov 2019, 07:59
by knowan
mixelflick wrote:As someone else pointed out, the SU-35 is more powerful and lighter.


Heavier

Re: Su-35. How the hell it did that?

Unread postPosted: 18 Nov 2019, 17:08
by milosh
knowan wrote:
mixelflick wrote:As someone else pointed out, the SU-35 is more powerful and lighter.


Heavier


It is lighter then Su-30MK which was in that video.

Su-30MK is two seater. Su-35 is single seater.

Su-35 weight is 17.5tons, Su-30MK is 17.7tons. Though some on net (Russian sources) are compare Su-35 to Su-27SK in therms of weight, Su-27SK is ~17tons.

Re: Su-35. How the hell it did that?

Unread postPosted: 18 Nov 2019, 21:22
by swiss
milosh wrote:
knowan wrote:
mixelflick wrote:As someone else pointed out, the SU-35 is more powerful and lighter.


Heavier


It is lighter then Su-30MK which was in that video.

Su-30MK is two seater. Su-35 is single seater.

Su-35 weight is 17.5tons, Su-30MK is 17.7tons. Though some on net (Russian sources) are compare Su-35 to Su-27SK in therms of weight, Su-27SK is ~17tons.


There is no way the Su-35 weight only 17.5 tons. Yes its a single seater. But as you can read above, the structure was reinforced to increase in the airplane’s maximum takeoff weight. The normal Takeoff weight is 25.3 tons with 2 РВВ-АЕ and 2 x Р-73E. ( 600 kg) and 50% fuel (5.7 tons) which give us 19 tons .

http://www.knaapo.ru/products/su-35/

This is also confirmed in a TASS article from September
https://tass.com/defense/1078209

The Su-35S supersonic fighter jet performed its debut flight on February 19, 2008. The fighter jet is a derivative of the Su-27 plane. The Su-35S weighs 19 tonnes, has a service ceiling of 20,000 meters, can develop a maximum speed of 2,500 km/h and has a crew of one pilot. The fighter jet’s armament includes a 30mm aircraft gun, up to 8 tonnes of the weapon payload (missiles and bombs of various types) on 12 underwing hardpoints. The Su-35S has been in service with the Russian Army since 2015.


The Su-30 MK has roughly the same weight as the Su-35s. Normal Takeoff weight is 24.9 tons with 2 x R-27R1 + 2 x R-73E and 5,270 kg of fuel.

https://www.uacrussia.ru/en/aircraft/li ... t-specific

Re: Su-35. How the hell it did that?

Unread postPosted: 18 Nov 2019, 22:44
by milosh
swiss wrote:There is no way the Su-35 weight only 17.5 tons. Yes its a single seater. But as you can read above, the structure was reinforced to increase in the airplane’s maximum takeoff weight. The normal Takeoff weight is 25.3 tons with 2 РВВ-АЕ and 2 x Р-73E. ( 600 kg) and 50% fuel (5.7 tons) which give us 19 tons .

http://www.knaapo.ru/products/su-35/


Where you have data about normal fuel weight? I don't see it on that site, nor anywhere else. Btw if you look you can see info about acceleration with 50% of fuel but at 1000m altitude. So 50% fuel isn't normal weight of fuel but at minimum weight of fuel it have when it reach 1000m.

With 19tons empty weight plane would be nowhere near agile as it is. And another problem is weight of Su-30 variants which is between 18-19tons.

Su-35 is smaller and use lot lighter materials, Al-Li and composites.

Even if it is same weight as Su-30MK it have more poweful engines and TVC which Su-30MK from heavy load demo don't have, so Su-35 would be noticeable more agile with such heavy and asymetrical load. But I still think it weight noticable less becuase how it regain energy is very impressive.

Re: Su-35. How the hell it did that?

Unread postPosted: 18 Nov 2019, 23:08
by swiss
Well, 19 tons fits perfect with 4 AAM and 50 % fuel, for 25.3 tons take off weight. As mentioned in the knaapo document. And i don't think TASS says 19 tons out of the blue. :wink:

Re: Su-35. How the hell it did that?

Unread postPosted: 19 Nov 2019, 03:40
by charlielima223
milosh wrote:With 19tons empty weight plane would be nowhere near agile as it is. And another problem is weight of Su-30 variants which is between 18-19tons.

Su-35 is smaller and use lot lighter materials, Al-Li and composites.

Even if it is same weight as Su-30MK it have more poweful engines and TVC which Su-30MK from heavy load demo don't have, so Su-35 would be noticeable more agile with such heavy and asymetrical load. But I still think it weight noticable less becuase how it regain energy is very impressive.


Maybe I am misinterpreting you about your opinion of weight in relation to agility.
The F-22 Raptor has an listed empty weight of 43340lbs, that is about 21.67 tons. At 50% fuel that would mean the F-22 would have a weight of 52340lbs or 26.17 tons. Despite this weight however the F-22 is able to demonstrate impressive AoAs, post stall maneuvers, and acceleration.
I would think that an important factor other than T/W ratio is also the aerodynamics of the aircraft as well as the flight control systems/logic/laws of the aircraft itself.

Re: Su-35. How the hell it did that?

Unread postPosted: 19 Nov 2019, 09:41
by disconnectedradical
We should clarify to make sure we’re using same units. A short ton is only 2,000 lb while a metric ton that Russia uses is 1,000 kg or 2,205 lbs, so F-22 is actually about 19.7 metric tons.