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By: - 20th August 2016 at 16:19 Permalink - Edited 1st January 1970 at 01:00
Hello,can someone point to a reliable source describing materials by % used in the Su-35 ?
How about other 4th & 5th gen planes ?
Cheers
These thing are not 100% static.
It may change a bit during a production period from start- 10 years -20 years.
New and better manufactor solutions, cheaper methods to create super alloys, which was very expensive prior..
By: - 20th August 2016 at 18:03 Permalink - Edited 1st January 1970 at 01:00
These thing are not 100% static.
It may change a bit during a production period from start- 10 years -20 years.
New and better manufactor solutions, cheaper methods to create super alloys, which was very expensive prior..
I agree with that, but if your first batch F-22 had 30% titanium I dont think the last batch has 95%, lets be serious.
Anyway, coming back to the topic at hand, any idea the combo for Su-35 ?
By: - 21st August 2016 at 17:40 Permalink - Edited 1st January 1970 at 01:00
I dont think that material used for a single design would change over time, change in material would change alot of things such as center of gravity, stress distribution, thickness, even the ways you put the aircraft together would be very different, metal required different kind of screws, bolts from composite material.. etc so on and so on. It would require alot of effort, may be even to the point that you will have to do all flights testing over again. To much effort for too minimum gain, unless you design a total new aircraft the material will likely to stay the same ( or at least stayed 99.999% the same, minus extra stuff like RAM)
By: - 21st August 2016 at 18:42 Permalink - Edited 1st January 1970 at 01:00
Today, you do not have to worry about getting 25 or 75 kilo shift in CG.
Any modern FCS will compensate for this trough its FBW.
How do you suppose the Sukhoi dealt with the Irbis-E on Su-35S which is way lighter vs BARS.
And add to that, each 117S engine is 75-100kg heavier vs AL-31FP; Su-35S =/= Su-30SM.
By: - 22nd August 2016 at 03:55 Permalink - Edited 1st January 1970 at 01:00
Today, you do not have to worry about getting 25 or 75 kilo shift in CG.
Any modern FCS will compensate for this trough its FBW.How do you suppose the Sukhoi dealt with the Irbis-E on Su-35S which is way lighter vs BARS.
And add to that, each 117S engine is 75-100kg heavier vs AL-31FP; Su-35S =/= Su-30SM.
You still have to do loads of flight test and stress test though and then the change in bolts , screws , thickness and a different manufacturing process would be a maintainance and logistics nightmare. While it should be possible in theory , i dont think they would do that in reality
By: - 22nd August 2016 at 05:32 Permalink - Edited 1st January 1970 at 01:00
As long as the shape of parts (fuselage parts) stays the same as before, but then they change it into a favorable stronger/lighter composite/super alloy, they do not necessarily need the change anything else.
I would think you could thrust the aviation industry to do this right. After all its what they are good at.
Take the Mig-29. How many times do you think they improved upon the airframe.. i'd say a lot.
By: - 22nd August 2016 at 05:40 Permalink - Edited 1st January 1970 at 01:00
Today, you do not have to worry about getting 25 or 75 kilo shift in CG.
Any modern FCS will compensate for this trough its FBW.How do you suppose the Sukhoi dealt with the Irbis-E on Su-35S which is way lighter vs BARS.
And add to that, each 117S engine is 75-100kg heavier vs AL-31FP; Su-35S =/= Su-30SM.
yes, modern FCS compensate, ....by adding trim drag
By: - 22nd August 2016 at 06:38 Permalink - Edited 1st January 1970 at 01:00
Some time trim drag reduce lift that lower induced drag... You can have a positive balance since a wing is a much larger surface than a small flap.
For example, most modern fighter use spanwise dissimilar lift to induce drag much better than a traditional airbrake ;)
By: - 22nd August 2016 at 06:52 Permalink - Edited 1st January 1970 at 01:00
As long as the shape of parts (fuselage parts) stays the same as before, but then they change it into a favorable stronger/lighter composite/super alloy, they do not necessarily need the change anything else.
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Sorry but i have to trim in abit . The problem with mechanic is not as straightforward as we would like it to be, there are more about a material rather than just strength and weight. There are mainy others factors that you have to consider like yield strength ,specific strength ,modulus of elasticity , heat resistance and so on. It rather impossible to come up with a new material that is superior to the old one in every single aspect,thus testing is a must. Take for example a common table comparision of carbon fiber and alluminium
The first look at the table will give you the impression that carbon fiber is far superior to alluminium in all aspect, however it is important to remember that all properties are at room temperature. Environmental conditions have a great effect on carbon composites ( If temperature goes up above 150 F, carbon fiber epoxy composite properties will be reduced somewhat whereas the steel and aluminum properties will remain the same).High humidity with heat will have an even greater effect. Moreover,the value above is for a single-direction , while carbon fiber needs to be layered in multiple directions (Otherwise all the fibers will be going in one direction and the material will be prone to splitting because there will be no strength in the cross-wise direction, just like wood veneer. If you layer carbon fiber in such as way as to have most uniform properties { aka “quasi-isotropic” laminate} you will end up with overall properties rather similar to aluminum.
That is just an example ,but you can see that chaging airframe material canbe rather complex and costly
Posts: 151
By: mikoyan - 20th August 2016 at 13:53
Hello,
can someone point to a reliable source describing materials by % used in the Su-35 ?
How about other 4th & 5th gen planes ?
Cheers