TR TF-X KAAN Fighter Jet

[neosinan]

They use aluminium to keep the cost low, since a titanium part of equal strength is lighter but is much more expensive and difficult to produce. Lockheed even had to redesign the F-35B bulkhead and change it from titanium to aluminium even though this made the plane heavier: link

In this Lockheed Martin presentation it says Aluminum bulkheads We are talking about is lighter and cheaper. This presentation is also the same presentation as @chngr shared one of its page.

In any case, Both Titanium and Aluminum bulkheads are forged according to this Lockheed Martin presentation.

http://www.rssummit.org/presentations/ball.pdf

 

[Nilgiri]

How will Aluminium resist to high pressures at high speeds?

Aluminum 7075, 7085 (7xxx in general actually) is quite proven (strength, toughness etc) and offers large scope of (relative) economical machinability...along with (relative) low weight.

Aluminum alloys are even used in engine blocks so they have a respectable strength. But at the end what counts is the material strength to weight ratio in aviation. Aluminum is an easy to process metal so it is an option to fall back to if better (?) choices can not be accessed to.

Spot on. No question mark needed, it will be very valid option for Turkey to consider right away (in fact its probably already been scoped out, I forgot to mention this earlier) if the Titanium 3d print + machining route faces any stumbling or related issue.

But why does K-FX use routed aluminum?

The milling choice (over say forging) and (contour-parallel) pattern is probably what the CAD/CAM predictor algorithm + analysis + verification gave as optimal factoring in:

a) Minimizing effects of grain flow anisotropy (esp considering this is still Al alloy in the end and it has no fatigue limit for any level of stress cycle, unlike Fe and Ti alloys).

b) You also want to keep compression-tensile considerations as similar w.r.t design parameters as possible (i.e preserve isotropy + dimensional stability) for this very reason too and also to mitigate work/strain hardening (and myriad of related+consequent effects) during service

c) The design relevance of acute angles and geometry involved in some of these edges (and their relevance to larger stress flow paths after assembly) in relation to precise forging potential to begin with

d) Required Tool feed + speed, other tool economics, time, costs, related economics, reliability and related QC/QA (given you don't want to over-age the Aluminium in stress concentrators etc by too much tool heat among other issues, given prior heat treatment + tempering already done, stress residuals, stress relief etc)

e) Any other general factors related to getting the most optimal amount of material removed closest to max theoretical weight reduction etc by the most optimal process .

All of these will relate to maximum flight hours the aircraft design is qualified for (given integral nature of these structures) w.r.t cost. I don't need to explain how important that is .

If any member would like any of this further clarified/explained, I would be happy to.

I hope to eventually cover some related metallurgy + processes etc in my jet engine series thread (found in signature)

@VCheng @Saithan @Joe Shearer @Saiyan0321 @T-123456 @Webslave

7085-T7452 = Aluminium alloy
Ti-6-4Eli = Titanium

It seems F35 central bulkhead are produced with single pieces forging titanium and Rest of the Bulkheads are produced with Aluminium for weight saving.

Yep, spot on. It is all based on the optimal stress flow path analysis w.r.t weight of material and fatigue cycle analysis for entire frame (among others). Similar to how wing spar material is often specifically chosen differently to rest of load carriers/dispersers...to optimise strength w.r.t weight of the whole system as economically but reliably as possible.

They use aluminium to keep the cost low, since a titanium part of equal strength is lighter but is much more expensive and difficult to produce. Lockheed even had to redesign the F-35B bulkhead and change it from titanium to aluminium even though this made the plane heavier: link

Good example. It happens quite frequently tbh. Titanium is not an easy material...esp for volume-intensive optimised geometries.

@anmdt @Sinan et al.

 

[Era_shield]

In this Lockheed Martin presentation it says Aluminum bulkheads We are talking about is lighter and cheaper. This presentation is also the same presentation as @chngr shared one of its page.

In any case, Both Titanium and Aluminum bulkheads are forged according to this Lockheed Martin presentation.

http://www.rssummit.org/presentations/ball.pdf

Not sure I'm understanding you but the presentation only says single-forged aluminium ones are lighter and cheaper than built up plate of aluminium. It doesn't say aluminium ones are lighter than the equivalent of titanium. Titanium has a higher strength/weight ratio than aluminium, actually it has the highest of any element.

 

[Bogeyman]

Osman OKYAY, Deputy Chairman of the Board of Directors of KALE Group, announced that they aim to work with Rolls-Royce company for the National Combat Aircraft - MMU engine.


"Together with Rolls-Royce, we submitted our proposal to develop the engine of the National Combat Aircraft domestically and our negotiations on this issue continue."

In 2017, they established a company called 'TAEC Aircraft Motor Industry Corporation' with Rolls-Royce in order to develop the engine of the 5th generation fighter aircraft developed within the scope of the National Combat Aircraft Project. 51% of the company's shares belonged to Kale Group.

Kale ve Rolly-Royce'dan MMU motoru teklifi | SavunmaSanayiST

KALE Grubu Yönetim Kurulu Başkan Yardımcısı Osman OKYAY Milli Muharip Uçak – MMU motoru için Rolls-Royce şirketiyle birlikte çalışmayı hedeflediklerini açıkladı

www.savunmasanayist.com

 

[adenl]

Osman OKYAY, Deputy Chairman of the Board of Directors of KALE Group, announced that they aim to work with Rolls-Royce company for the National Combat Aircraft - MMU engine.


"Together with Rolls-Royce, we submitted our proposal to develop the engine of the National Combat Aircraft domestically and our negotiations on this issue continue."

In 2017, they established a company called 'TAEC Aircraft Motor Industry Corporation' with Rolls-Royce in order to develop the engine of the 5th generation fighter aircraft developed within the scope of the National Combat Aircraft Project. 51% of the company's shares belonged to Kale Group.

Kale ve Rolly-Royce'dan MMU motoru teklifi | SavunmaSanayiST

KALE Grubu Yönetim Kurulu Başkan Yardımcısı Osman OKYAY Milli Muharip Uçak – MMU motoru için Rolls-Royce şirketiyle birlikte çalışmayı hedeflediklerini açıkladı

www.savunmasanayist.com

A competitor to TRmotor, or are they part of it?

 

[TR_123456]

Aluminum 7075, 7085 (7xxx in general actually) is quite proven (strength, toughness etc) and offers large scope of (relative) economical machinability...along with (relative) low weight.




Spot on. No question mark needed, it will be very valid option for Turkey to consider right away (in fact its probably already been scoped out, I forgot to mention this earlier) if the Titanium 3d print + machining route faces any stumbling or related issue.




The milling choice (over say forging) and (contour-parallel) pattern is probably what the CAD/CAM predictor algorithm + analysis + verification gave as optimal factoring in:

a) Minimizing effects of grain flow anisotropy (esp considering this is still Al alloy in the end and it has no fatigue limit for any level of stress cycle, unlike Fe and Ti alloys).

b) You also want to keep compression-tensile considerations as similar w.r.t design parameters as possible (i.e preserve isotropy + dimensional stability) for this very reason too and also to mitigate work/strain hardening (and myriad of related+consequent effects) during service

c) The design relevance of acute angles and geometry involved in some of these edges (and their relevance to larger stress flow paths after assembly) in relation to precise forging potential to begin with

d) Required Tool feed + speed, other tool economics, time, costs, related economics, reliability and related QC/QA (given you don't want to over-age the Aluminium in stress concentrators etc by too much tool heat among other issues, given prior heat treatment + tempering already done, stress residuals, stress relief etc)

e) Any other general factors related to getting the most optimal amount of material removed closest to max theoretical weight reduction etc by the most optimal process .

All of these will relate to maximum flight hours the aircraft design is qualified for (given integral nature of these structures) w.r.t cost. I don't need to explain how important that is .

If any member would like any of this further clarified/explained, I would be happy to.

I hope to eventually cover some related metallurgy + processes etc in my jet engine series thread (found in signature)

@VCheng @Saithan @Joe Shearer @Saiyan0321 @T-123456 @Webslave



Yep, spot on. It is all based on the optimal stress flow path analysis w.r.t weight of material and fatigue cycle analysis for entire frame (among others). Similar to how wing spar material is often specifically chosen differently to rest of load carriers/dispersers...to optimise strength w.r.t weight of the whole system as economically but reliably as possible.



Good example. It happens quite frequently tbh. Titanium is not an easy material...esp for volume-intensive optimised geometries.

@anmdt @Sinan et al.

I just want to know if Aluminum 7075, 7085 (7xxx in general actually) can be used as engine ''casing'' and if not,what can be used other then Titanium?

 

[Oublious]

How will Aluminium resist to high pressures at high speeds?

duralumin...

 

[Yasar_TR]

A competitor to TRmotor, or are they part of it?

Neither! TR Motor, would like to think they are part of it. But RR will not give IP rights to TR Motor.
So only scenario I see is RR/Kale produce the engine in Turkey under license with permission to sell to third parties and sell it to Tusas. They may use TEI for some parts. But whether they do or not TEI will carry on with the development of an indigenous engine.
If you do not know the structure of engine manufacturing for the Turkish defence industry;
TR Motor is a design bureau. They also hold the rights of engines produced by TEI and Kale.
A bit like Ukraine’s Ivchenko progress and Motor Sich!

 

[Nilgiri]

I just want to know if Aluminum 7075, 7085 (7xxx in general actually) can be used as engine ''casing'' and if not,what can be used other then Titanium?

Generally for casing, there is more thermal gradient considerations (and impact resistance consideration) to consider above the stress handling itself, depending on the location along the jet engine (cold vs hot may broadly change what you decide to use).

So for example since the compressor blades are generally titanium, to not have too much issue with thermal expansion, you make the "inner" casing in this area of the same material...so that you dont have to worry too much about clearances and such changing too much (w.r.t stator and rotor).

But "outside" casing bulk of it you might indeed just go for a cast aluminium even (don't even need 7075 tbh since we aren't after load bearing much). Or you might continue with Titanium if you want (make just one bulk casing esp for military given volume + weight available is restricted).

On commercial jet engines there can increasingly be a composite or kevlar-based casing here (to both reduce weight and offer maximum impact resistance for rogue blade containment (given larger safety requirement compared to military, and the fact engines are located outside the fuselage etc.).

Hot section (turbine) same kind of concept (keep materials consistent), i.e the innards are generally nickel super alloy (with appropriate thermal barrier coating etc), so you need to make the inner casing out of same material for reliability ease w.r.t tolerances and such (w.r.t stator base etc). Generally an "outer" casing concept doesnt apply here (given bypass in turbofan), they just have bulk nickel super alloy casings for hot. That's why you often see "another" casing or two (depending on # of turbine stages) sticking out the end in say a commercial engine (and which has the larger nacelle for the fan + bypass air):

Military jet engines things are kept even more compact...and the afterburner nozzle needs a nickel super alloy + TBC anyway, so they just keep things fairly the same till the end for the (hot section) casing...and maybe have titanium (bulk simplicity) for the cold section, but any interface shroud etc past it might be aluminium (if its fine to have in analysis) etc:

GE 404 example:

 

[TR_123456]

Generally for casing, there is more thermal gradient considerations (and impact resistance consideration) to consider above the stress handling itself, depending on the location along the jet engine (cold vs hot may broadly change what you decide to use).

So for example since the compressor blades are generally titanium, to not have too much issue with thermal expansion, you make the "inner" casing in this area of the same material...so that you dont have to worry too much about clearances and such changing too much (w.r.t stator and rotor).

But "outside" casing bulk of it you might indeed just go for a cast aluminium even (don't even need 7075 tbh since we aren't after load bearing much). Or you might continue with Titanium if you want (make just one bulk casing esp for military given volume + weight available is restricted).

On commercial jet engines there can increasingly be a composite or kevlar-based casing here (to both reduce weight and offer maximum impact resistance for rogue blade containment (given larger safety requirement compared to military, and the fact engines are located outside the fuselage etc.).

Hot section (turbine) same kind of concept (keep materials consistent), i.e the innards are generally nickel super alloy (with appropriate thermal barrier coating etc), so you need to make the inner casing out of same material for reliability ease w.r.t tolerances and such (w.r.t stator base etc). Generally an "outer" casing concept doesnt apply here (given bypass in turbofan), they just have bulk nickel super alloy casings for hot. That's why you often see "another" casing or two (depending on # of turbine stages) sticking out the end in say a commercial engine (and which has the larger nacelle for the fan + bypass air):

View attachment 12389

Military jet engines things are kept even more compact...and the afterburner nozzle needs a nickel super alloy + TBC anyway, so they just keep things fairly the same till the end for the (hot section) casing...and maybe have titanium (bulk simplicity) for the cold section, but any interface shroud etc past it might be aluminium (if its fine to have in analysis) etc:

GE 404 example:

View attachment 12390

And what about the engine bay,what kind of material(only fighter jets)?
With all the heat coming from the engine?
Or does the airflow take care of the heat problem?

 

[Nilgiri]

And what about the engine bay,what kind of material(only fighter jets)?
With all the heat coming from the engine?
Or does the airflow take care of the heat problem?

Thermal gradient is largely mitigated by time it reaches engine bay itself by a few different ways.

There is active cooling with bleed air (allowed to flow around the casing)...a blanket of cooler air basically. This is done in various ways but they all help to drastically reduce any direct conduction from the engine heat to the interface shroud and body (from hot section).

There can be insulation blanket materials for the turbine section specifically too (unsure how much this is used for military though). Shroud design also helps with this.

The very action of bypass flow (if its turbofan) also helps from the get go (i.e at casing skin you are not going to see anything close to say turbine inlet temp).

Here is actually good summary I just found with more details:

Aircraft Reciprocating Engine Cooling Systems and Maintenance

Technical knowledge for Aviators on aircraft systems and components maintenance; theory; methods; procedures; troubleshoot; repair; testing; diagrams;

www.aircraftsystemstech.com

 

[Era_shield]

I just want to know if Aluminum 7075, 7085 (7xxx in general actually) can be used as engine ''casing'' and if not,what can be used other then Titanium?

If we're talking only about fighter jet engines, some sections can be but not all. The AL-31 engine has an IGV outer casing of aluminium alloy, not sure exactly which alloy, but other sections are nickel based alloys or titanium. Titanium used to be used for casing in the most advanced engines in the 70s/80s but due to the risk of titanium fires some manufacturers switched to other materials like steel (source), but some still use it with a special coating. In the EJ200 for example, the outer and intermediate casings are titanium but the stage 5 inner casing is incoloy.

 

[AzeriTank]

Generally for casing, there is more thermal gradient considerations (and impact resistance consideration) to consider above the stress handling itself, depending on the location along the jet engine (cold vs hot may broadly change what you decide to use).

So for example since the compressor blades are generally titanium, to not have too much issue with thermal expansion, you make the "inner" casing in this area of the same material...so that you dont have to worry too much about clearances and such changing too much (w.r.t stator and rotor).

But "outside" casing bulk of it you might indeed just go for a cast aluminium even (don't even need 7075 tbh since we aren't after load bearing much). Or you might continue with Titanium if you want (make just one bulk casing esp for military given volume + weight available is restricted).

On commercial jet engines there can increasingly be a composite or kevlar-based casing here (to both reduce weight and offer maximum impact resistance for rogue blade containment (given larger safety requirement compared to military, and the fact engines are located outside the fuselage etc.).

Hot section (turbine) same kind of concept (keep materials consistent), i.e the innards are generally nickel super alloy (with appropriate thermal barrier coating etc), so you need to make the inner casing out of same material for reliability ease w.r.t tolerances and such (w.r.t stator base etc). Generally an "outer" casing concept doesnt apply here (given bypass in turbofan), they just have bulk nickel super alloy casings for hot. That's why you often see "another" casing or two (depending on # of turbine stages) sticking out the end in say a commercial engine (and which has the larger nacelle for the fan + bypass air):

View attachment 12389

Military jet engines things are kept even more compact...and the afterburner nozzle needs a nickel super alloy + TBC anyway, so they just keep things fairly the same till the end for the (hot section) casing...and maybe have titanium (bulk simplicity) for the cold section, but any interface shroud etc past it might be aluminium (if its fine to have in analysis) etc:

GE 404 example:

View attachment 12390

Today, head of TEI, Turkish engine giant said they are the only company after GE that able to produce compressor and blades together as a single unit that's why why got 5 billion $ order from GE, also became main contractor of Safran and other commercial engine producers..

 

[Nilgiri]

Today, head of TEI, Turkish engine giant said they are the only company after GE that able to produce compressor and blades together as a single unit that's why why got 5 billion $ order from GE, also became main contractor of Safran and other commercial engine producers..

Not sure what he means by that (or the exact words) as my company (PW) and rolls royce does that (blisk manufacture) and I would imagine Snecma and some others too.

But the achievement for Turkey is notable one, I would imagine GE was attracted to go for JV with TEI earlier for this very reason:

GE and TEI Engine Industry in Joint Venture for Manufacturing Blisk in Turkey

TEI will become a specialized manufac

www.defenceturkey.com

 

[AzeriTank]

Not sure what he means by that (or the exact words) as my company (PW) and rolls royce does that (blisk manufacture) and I would imagine Snecma and some others too.

But the achievement for Turkey is notable one, I would imagine GE was attracted to go for JV with TEI earlier for this very reason:

GE and TEI Engine Industry in Joint Venture for Manufacturing Blisk in Turkey

TEI will become a specialized manufac

www.defenceturkey.com

he said normally you chnage those blades after flights, as if you dont, and if they go out, it will destroy the whole engine. he said Turkey lost most of f16th because of this failure. but with this technic, they make it from a single crystal.. so you dont need to care about it much.. he een said, the US embassy army attaché came to visit them, when he showed their this technology, he was shocked how they did it.. He said, because of their making this technology, all commercial flight ticket prices around the world came down 20-30%

 

[Nilgiri]

he said normally you chnage those blades after flights, as if you dont, and if they go out, it will destroy the whole engine. he said Turkey lost most of f16th because of this failure. but with this technic, they make it from a single crystal.. so you dont need to care about it much.. he een said, the US embassy army attaché came to visit them, when he showed their this technology, he was shocked how they did it.. He said, because of their making this technology, all commercial flight ticket prices around the world came down 20-30%

I think I understand more now. It is probably an application of blisk to military use for F-16 engines (if say some of these were non-blisk ) that Turkey has extended into...and probably what impressed the army attache.

Single crystal is something else, thats the turbine side of things.

Blisk is single piece I would say.

Yes the context of blisk since the 90s has led to economy of scale in MRO industry leading to lower prices (as less downtime for the commercial aircraft).

 

[AzeriTank]

I think I understand more now. It is probably an application of blisk to military use for F-16 engines (if say some of these were non-blisk ) that Turkey has extended into...and probably what impressed the army attache.

Single crystal is something else, thats the turbine side of things.

Blisk is single piece I would say.

Yes the context of blisk since the 90s has led to economy of scale in MRO industry leading to lower prices (as less downtime for the commercial aircraft).

not only military, they sell it to commercial Turbofan engines... about the single crystal you are right, he said it on Turbine part. he said the name of engine that 80% of all commercial planes use.. basically they do it all for them..

 

[Nilgiri]

not only military, they sell it to commercial Turbofan engines... about the single crystal you are right, he said it on Turbine part. he said the name of engine that 80% of all commercial planes use.. basically they do it all for them..

Yes the JV between GE and TEI was for production of blisk for CFM LEAP engine after all. Maybe TEI has found a process innovation within it.

 

[Zafer]

Yes the JV between GE and TEI was for production of blisk for CFM LEAP engine after all. Maybe TEI has found a process innovation within it.

TEI made many process innovations especially in surface finish area.

 

[Yasar_TR]

Main points of the M F Aksit interview:
1. PD170 ; Currently in use on Anka there is now a PD180 model in the works , 10kg lighter but will have more power for TB3 Bayraktar.
2. PD222 ; Already Ank has flown with it. Aksungur too. This engine will also be used on a lighter longer endurance model of Akinci.
3. TJ90 ; Was originally a test bed to see if an indigenous turbojet can be produced. Success ended with the use of the engine on “Simsek” target jet drone.
4. TJ300 ; Was a test bed for an axial flow jet engine. It turned out, it could be used as an engine for Medium Range Anti Ship Missile.
5. F110 ; All Turkish F16 engines were put together in TEI with a handful of pieces actually produced in situ. But Today more than 50% of all critical parts of that engine can be produced in house and the complete engine can be put together with some minor parts outsourced. In fact the TFX will have an indigenous engine. May not be the first plane but the one after definitely.
6. CFM, RR, P&W and GE all use TEI large blisk technology. In fact there are some critical parts produced by TEI on at least 50% of all the aircrafts today that is in the air, be it civilian or military.
7. TS1400 ; there will be 6 or more prototype engines whereby small glitches will be ironed out during the integration process. Then there will be a qualification process for the engine. This will take around 3 years. But this engine has opened the way to produce much bigger and more powerful engines for us. Be it gas turbines for ships, turbofans or turboprops.