LMFS[USER=”3598″]Austin[/USER]
Thanks for the article Austin. I am not very convinced it is very reliable though. Many assumptions are taken out of nowhere, some others seem false so it seems a bit of a mishmash of different sources, some official and some not without a very good filtering
Thrust Data is from interviews from UEC chief , 117 Thrust of 15 T in A/B is a known thing
Great, thanks
LMFSUPDATE ON TURKEY AND THE F-35 Saga;
Trump Administration apparently conveys to Turkey that it was “justified in procuring the S-400”: https://ahvalnews.com/turkey-us/trum…e-says-erdogan
Trump Administration apparently also guarantees delivery of Turkey’s F-35 and implies that Ankara should ignore statements made by media and US Congress:
Turkey says it will still not abandon its other programs: TF-X and S-400…Looks like Trump does not want a $20 billion whack on Boeing
WTF!!?? This is getting incredibly surreal :stupid:
LMFSCould we please move the discussion on which aircraft, besides the F-35, Turkey may operate on its aircraft carrier to an appropriate thread and keep this thread about the F-35 News and Discussion as the title suggests.
True, beyond this point it belongs somewhere else. But the discussion started logically as a F-35 topic.
LMFSTurkey has had an agreement with Mr. Putin for the acquisition of some Su-35 and S-57 (with Turkish (NATO Standard) Sub-systems and weapons systems) as a stop gap measure until Turkey’s TF-X enters service in 2025 in the event that the F-35 program was not viable. Turkey knew all along that Washington may use the F-35 as a bargaining chip when Turkey was interested in the Russian S-400’s.
Thanks Bayar. I interpreted such comments as warnings, I did not thought there were already concrete agreements in place. I can see Russia pushing preferentially the MiG-35 with a big discount (they will want to push the exports of the new model) or in case Turkey insists, a Su-35 that I am sure would give Turkey much food for thought in terms of developing the TF-X. Picking the Su-57 is not really a stop-gap measure, since it can provide both air superiority and strike roles at a very high level long term… operationally it would end up threatening the TF-X. Don’t know if Russia would be ready to launch a modification and co-production program for the Su-57 for a minor Turkish buy. Turkish-Russian relations are not the simplest ones either, with a number of implicit conflicts still unresolved, so there would need to be seen how the negotiations would pan out it terms of transferring most advanced military technologies.
Turkish Airlines has also been asked to cancel a $20 billion order for Boeing Jets in the event that Turkey is kicked out from the F-35 program.
That would be serious retaliation, Boeing is not in the best moment to get a $20 billion hit… I wonder what further vulnerabilities Turkish military, as NATO member and previously strong US partner has in case cooperation is stopped. The engines for the T129, spares for F-16 spring to mind but surely there are hundreds of items where some kind of interdependence exists. Is Turkey in your opinion in conditions to withstand the backlash of a full blown US response until the end? And, as NATO partners, how far US can go without forcing Turkey out of the alliance? It is easy to see where a quarrel starts but difficult to predict where it can stop…
Turkey and London are also discussing Turkish partnership in the Tempest for 2035 requirements.
Fight with US and be friends with UK comes across as an impossible goal to me. Rolls Royce was apparently scaling down efforts for the engine of the TF-X already but maybe I am wrong. I mean, everybody likes money and will be ready for partnership, but if someone above orders to stop the party it can leave Turkey with a lot of investments done and an unfinished project in their hands. Ambivalence West-East has helped Turkey a lot but West is not used to their partners flirting out with the East too .I am inclined to think this ambivalence is not going to be tolerated in the future.
TCG Anadolu will now primarily use Turkish Aerospace T-129’s, T-130 Heavy Atak II’s, Unmanned Aerial Vehicles. So essentially they will act as helicopter carriers with limited strike capability- the Akinci UAV has AESA radar and a weapons payload of 1.5 Tons. The Light Carrier/LHD is due to be launched in 2 months time.
There is also now talk of a Naval Variant of the TF-X for use on a conventional 40,000 to 60,000 ton Carrier as Turkey wants full operational sovereignty and independence.
Sounds reasonable and is clearly another opportunity for cooperation with Russia, which has the proper planes and develops carriers in that tonnage.
LMFSTurkey is not voluntarily leaving the F-35 program as in “abandoning” the program. They are still a partner and have a desire to be. If the S-400 sale goes through this summer (deliveries) then the US Government and the Congress would have to evaluate whether 1) Turkey still gets its F-35A’s 2 ) Turkish companies stay within the JSF program as suppliers. If they decide NO then Turkey’s participation will formally be terminated and the existing aircraft (6) and those on order (24) will be allotted to other operators. I don’t think Turkey will voluntarily leave the program unless formally kicked out though some folks, including me, hope that they do and make it easy on everyone else involved politically.
The way it was stated did indeed sound like “we know how this is going to end so we leave ‘voluntarily’ the program”, which may make sense in order to save face and also to actively start searching for alternatives asap. Turkey could also do as if nothing happens and insist in getting their fighters, that is what I had heard until now and what makes sense in order to place a complaint for contract breach. Not that they are going to get any compensation any time soon but at least they should try. What would be a massive failure by Turkey now would be to buy the fighters, given the state of the trust between both countries and how easily US could ground the fleet. What has happened cannot be undone now.
LMFSThe J-31 is about the only other game in town that’s going to be available in the next 15 years. Su-57 maybe? But I’m not sure they’ll get technology transfer or operational sovereignty there either.
Su-57 would be a very good option even when it would be actually a substitute to both F-35 and TF-X, and I don’t think that is wished. But I guess they could get good price and ToT on it, it should be very interesting to Turkish industry, not so sure about long term consequences for Russia. There could be also cheaper options but older than F-35 from China, Europe and Russia, they could be acceptable as stop-gap measures if TF-X is modified to cover strike roles. What I don’t see is a substitute for the F-35B…
LMFSTurkey’s Undersecretary for Defense Industries says Turkey would prefer co-production of the S-400 and S-500 with Russia any day of the week- over mere procurement of the F-35 from Lockheed Martin and that it was not the end of the world if the remainder of Turkey’s F-35’s were not delivered by the US. He added that Turkey’s priority was “operational sovereignty” and “technology transfer”.
It is now safe to say that but for the 2 F-35’s that have already been delivered to Turkey- Turkey will not be a partner in the JSF consortium in the near future.
Wow, that sounds very conclusive, do you think is that serious? Do you mean a definitive abandonment of F-35 program?
And how is Turkey expected to substitute the gap left by the F-35, is there a plan at all that you know? I mean, apart from AF you were expecting to buy the STOVL version too for the navy, right?
LMFS117 Engine is 150 kg lighter than AL-31 and Thrust of 15 T , Dry weight of AL-31 is 1520 ( http://roe.ru/eng/catalog/aerospace-systems/engines/al-31f/ ) , So 117/AL-41F1 weighs 1370 trust at 15T gives T:W Ratio of 10.9 or ~ 11: 1
Good to use ROE data for the weight of the AL-31. Where did you find the thrust data of the 117?
LMFSInstead of brags, what’s some actual numbers? 117S is 1,604 kg with 14.5 tons of thrust so t/w is 9. So if izd.30 is about 25% better, then t/w of 11.3, so similar to F-135 then?
No, they are not obligued to give away any numbers. Besides, they are not referring TWR but specific thrust. As said, TWR of AL-41F1 is around 10. That value is IMHO not going to be 25% better in Izd. 30 by increasing thrust a 25% since the engine’s diameter remains largely the same, it would need to be rather through a very serious reduction in weight that you could reach a 25%improvement, and that is not a given. They said Izd. 30’s TWR would be above 10 and that’s all the information we have.
LMFSWhy are we comparing the t/w of this engine to the F-135? I am sure that VTOL needs a lot of thrust to take of vertically than an aircraft that has to use a runway.
There is a F135-PW-100 which is the engine for the CTOL version of the F-35 and is widely supposed to be the best fighter engine available and thus the reference right now. It is said to produce 128.1 kN thrust dry, 191.3 kN wet (28,000 and 43,000 lb respectively).
The engine for the STOVL version is the PW-600. When configured for short take off or hovering, the thrust augmentation derived from A/B is not used but instead the BPR is notably increased through the additional lift fan. Thrust from the nozzle is notably reduced due to the big amount of power extracted at the turbine to move the fan and high pressure air bled from the compressor to feed the roll posts. Engine does NOT operate with A/B with the nozzle bent downwards. Total thrust is 175.3 kN, including nozzle, lifting fan and roll posts.
So conventional take-off configuration gives more thrust that hover or short take-off configuration, STOVL has nothing to do with any claimed extra thrust.
If that t/w was correct wouldn’t the F-35 easily outrun the SR-71 and even the claims of mach 4 with the mig-41?
No, drag at supersonic speeds in F-35 is very high. Also max temperature the engine can operate under and configuration of the intakes (no variable ramps) limit fundamentally the speed of the plane. F-35 is not an aircraft designed to be a supercruiser or a highly supersonic interceptor, its engine has high BPR and is hence optimized for subsonic flight.
What measurements did you take to get t/w of 11.3? Wikipedia is telling me this for the F-35 regarding t/w.
- With full fuel: 0.87
- With 50% fuel: 1.07
and for the SU-57 its telling me this.
- AL-41F1: 1.02 (1.19 at typical mission weight)
- izdeliye 30: 1.16 (1.36 at typical mission weight)
Did I miss anything?
Data in Wikipedia are not to be taken seriously, they are unreliable and much less if you use TWR of the whole plane as starting point of your calculation. For instance, no official MTOW of the Su-57 is available and for the F-35 only information is 60,000 or 70,000 lb class. No official info about Izd. 30 thrust available either. The thrust I indicate above for F135 is credible though. Best weight estimates (USAF) indicate 3750 lb for the engine, that would mean TWR = 11.46. AL-41F1 is around 10 with the available information.
The article linked by Austin really means specific thrust is better than analogues. That is, more thrust per flow mass.
LMFSI am sorry but the airframe is symmetrical regarding a vertical plan encompassing its main axis meaning that it is at least neutral in ‘lateral’ (yaw) and roll. It can be divergent of course but not “unstable”.
Notice that I have long ago supposed that the -Fa* was made able to fly sideway efficiently (frontal stealth).
AFAIK the term “unstable” referred to planes means that, instead of having a tendency to return by themselves to horizontal levelled flight, they will keep or even amplify a given deviation command. For instance a F-16 can keep a “nose up” attitude even when the elevators are levelled whereas a “stable” plane would not.
In terms of lateral instability I am also not sure if they refer to yaw, roll or both. In any case, stability to roll moment depends normally on the wings dihedral and position of CoG among others, given its layout it may well be that Su-57 has very little roll stability. Don’t know much about yaw stability
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BTW what do you mean with your last sentence?
LMFSLMFSSubsonic: “cruise mode”. This does fit – even with superior thermal efficiency thanks to higher TET & OPR a F119/EJ200-style leaky turbojet for good supersonic SFC may very well have *worse* fuel consumption than the AL-31F at subsonic speeds due to inferior propulsive efficiency (see F404 vs. RD-33 static dry SFC).
2400kg may well be an accurate weight for the F135, but only the -600 with all the STOVL bells & whistles (lift fan plus drive shaft, roll posts & 3BSN).
On a related note: this article once again brings up the specific thrust & specific weight conundrum noted by RadicalDisconnect and myself a while ago. I’ve since realized that specific thrust indeed is probably used in the conventional sense (thrust per mass flow), and that the seemingly modest improvement claimed is likely due to higher TET rather than lower BPR. Everything else equal (and with variable cycle now distinctly possible Izd. 30 BPR may well be comparable to the AL-31F in subsonic cruise!) higher temperature before the turbine will increase thrust per mass flow – IIRC a very rough estimate indicated the improvement stated in those earlier sources corresponds to something like 200K worth of TET which is a plausible scale.
OK thanks Trident, I think I start to understand:
– So you think the main goal of the VCE technology in Izd. 30 would not be the subsonic cruise but the supersonic flight, hence reduction of the BPR in that regime in order to increase dry thrust like in F119? And that max BPR of such an engine would be similar or even little lower than AL-31? For the comparison, AL-31F has BPR ca. 0.6:1 and SFC almost identical to EJ200 with BPR 0.4:1 so it indeed seems improvements in thermal and compression performance can compensate for lower BPR to a certain extent.
– Specific thrust: yes, they mention in the article they refer thrust per mass flow. But I don’t see where they claim the improvement to be modest
– What about the intakes? Couldn’t we know more about design philosophy and maybe even quantitative values of the Izd. 30 based on their design, since they determine the mass flow?
– VCE issue: ok just now I get that Izd. 30 could be variable cycle, just not yet including the third air stream, which apparently is going to be important to evacuate heat from the plane and so expected to be relevant for the power demands of 6G planes. It would be a major development of the program indeed, if Izd. 30 was that kind of engine… do we have SFC values of the F119 to compare? This is IMO the only other supercruising engine available and we would probably get an idea of whether SFC values like those in AL-31 are possible for such a supersonic-regime optimized engine without a VCE configuration
LMFSInteresting aside, while looking for an article about the time needed to swap out the F135 engine, I came across the actual weight from a page regarding engine maintainers. I cannot relocate it, or Hill afb realized the error and removed the information.
Needless to say I was surprised at the weight (cannot remember), but suffice to say that the estimates on wikipedia etc are off, way, way off. The engine does not weigh anything near 2,400kg.
Got it:
Good find, thanks!
Those values (43000 lb thrust vs 3750 lb weight) give some respectable 11.46 index in the T/W ratio or 0.087 specific weight for the F135. I think this looks about correct, considering values of previous engines. So, if it is true that Izd. 30 goes beyond this, they are not revealing nothing important by indicating the value is lower than 0.1. It would be nevertheless interesting to see what thrust values are available with the new engine, given it will have more or less the same size and less components than AL-41F1 it should be notably lighter. So either it reaches a huge value in the T/W ratio or it may paradoxically not provide substantial thrust advantages above the old model!
Regarding the VCE issue, it seems confusing and I lack the Russian speaking skills to read deeper into what the designer said. It would be strange that Izd. 30 was a VCE, considering its specific fuel consumption is not much better than that of AL-31, so BPR should be fixed and similar to that of the AL-31.
LMFSSome interesting notes :
1.Development target of T/W of 10:1 has not change.
2.Internal Weapon Bay capacity of Su-57 is about 4200 Kg.
3.Still hasn’t give up on flat nozzle eh.
They say the specific weight is LOWER than 0.1, if I am not wrong that value was already reached with AL-41F1. Also it was stated previously that Izd. 30 would surpass all analogues in terms of specific weight, that would be another useful indication, if we only had a reliable value for F135 as probably the best foreign competitor.
The flat nozzle thing, I interpret it as “we could do that too if somebody would pay”. At the moment they have already a “stealthy-looking” 3D TVC nozzle for Izd.30 that should be lighter and more useful…
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