Hi dear
@araz
I will begin my response touching two major areas from your comment-
(a) Tejas
(b) Wing loading of JF-17 and how it might potentially define the instantaneous and sustained turn rates.
I would like to make it very clear that I do not wish to delve into the strategy of war fighting and certainly the figure of 1:2 or 1:x is rather debatable and would depend on a lot of parameters viz- network centricity,sophistication of the platform,various countermeasures,degree of threat in which either of aircrafts fly etc etc. I will leave this debate to other members and shall focus on (a) and (b) on strictly technical lines.
(a)Tejas as you have wrongly pointed out wont be just a "experimental technological demonstrator".It was and is supposed to replace the mig-21s. It sure wont be a cutting edge or even IAF's top of the line fighting platform but it will fulfill itz intended role in bigger scheme of things in IAF. India has already spent close to $2.5-$3bn(by varying estimates) on just the R&D of tejas. This R&D includes a lot more than you can fathom sitting in the comforts of your room. A lot of pakistanis who are not familiar with any kind of research let alone aerospace research keep making brazen remarks without knowing the true contribution of various labs and colleges like my own that went into Tejas- this kind of "industry-academic" interaction doesnt even exist in pakistan!
(b) Wing loading.
Wing loading is an important parameter in aerial dogfighting but it ALONE doesnt quantify the sustained turn rates.If you ever had a chance to analyze the EM graph,you would quickly point out that the maximum instantaneous turn rate occurs at the max possible "G" or load factor and at a velocity that is also known as corner velocity.
View attachment 336094
Picture Courtesy: SimHQ
In the graph above the solid line that envelops everything else corresponds to ITR(instantaneous turn rate). For this particular aircraft the max ITR occurs when a 6g turn is pulled at somewhere around 260mph. But we need to ask this question can we sustain this turn or for that matter any turn?By sustaining a turn I mean,can be make a turn "without bleeding any energy" and hence "altitude"?To answer this question we need to go a bit deeper.
Lets imagine we calculated that top corner velocity using very simple calculations and got some results ,lets call it x dps. To pull x-dps,we can also calculate the corner speed ,lets call it V1.To ascertain whether we can sustain this rate,all we need to do is find the drag coefficient which is famously given by drag polar and using it find the drag!Lets call the drag we obtained in previous step as D1.
If our Tmax<D1- then we can NEVER sustain that turn rate no matter what!
The aircraft will loose energy and hence height as indicated by dotted lines below that top bold line.The rate at which aircraft will loose altitude is determined by "how far you're away from STR line".The STR line is the solid line in the middle of the graph which has 0 written over it and itz corner shows the max STR possible.That 0 also indicates that if you're on that line,you wont be loosing any energy hence altitude.
You see,a sustained turn rate is perhaps a more useful parameter from dogfight perspective vis-a-vis ITR that merely works as a sign post-where you want to eventually go to. Theoretically speaking ,sustained turn rate is a kind of turning maneuver where thrust is strictly equal to drag. Lets call this condition (1).It is because of this condition that wing loading is inversely proportional to the turn rate. Condition (1) is also sometimes known as "un-constrained" case.
But condition (1) can at times gives mis-leading information as we have not included two major constraints in a flight-
(a) Clmax-max Cl possible
(b) Nmax- or max load factor- structural or aerodynamic limit.
So,ideally speaking our job is to maximize the turn rate equation,subjected to following equalities or inequalities-
(1)T=D
(2)Cl=Clmax
or
(3)n=nmax
We have to choose between (2) and (3),and as my calculations show (2) normally yields higher sustained dps than (3).
PS-if you want to see all the calculations,I can post screenshots of my rough.
PSS- skardu is almost 1000m lower than Leh airbase.
@Oscar
