But one can appreciate the Indian position as well — it guarantees that ToT will be delivered in a timely and moreover useful fashion.

Yes… but as the old saying goes, “you can lead a horse to water, but you cannot make it drink”.

The Indian negotiating position is tantamount to insisting that Dassault not only lead the horse to the water, but they must make it drink.

Probably better off handing HAL (or whoever) the design data of the relevant parts, then let them replicate them – any questions on the design/process/etc must be answered by Dassault in timely fashion otherwise contract penalties ensue.

Your point is moot overall anyway, because if you examine my calculation it relies on ratios pertaining to one aircraft only, and is not extended beyond that. I.e. whether we take the lower or upper fuel density for the fuel the ratio of internal fuel to total fuel for an Su-35 is the same.

You cannot compare between aircraft without ensuring you are consistent.

You cannot even generate fuel fraction vs. tank fill level without knowing fuel density!

You don’t have consistent tank volumes but are using kg which have been determined using unknown fuel densities.

e.g. How much fuel (in kg) is there in a 50% full Flanker? That answer depends on the fuel density and tank volume. Neither of which are stated in any calc I’ve seen to date in this thread.

Same for Eurofighter.

[N.B. They quote in kg as it could mean anything. Its done for a reason.]

The Eurofighter has a fuel tank volume of approximately 5700 litres. [albeit, its classified, so thats a best guess]

At a fuel upper density of 0.876 kg/litre, that is just under 5 tonnes.
At a nominal fuel density of 0.785 kg/litre, that is 4.475 tonnes.
At a lower bound density of 0.743 kg/litre, that drops to 4.235 tonnes.

For the Su-27, estimated tank volume is around 11,775 litres – but the full g envelope is only available for fuel volume below ~6,600 litres due to limits of various tanks in the system.

For the various fuel densities then:
0.876 = 10.315 tonnes/5.78 tonnes
0.785 = 9.245 tonnes/5.18 tonnes
0.743 = 8.750 tonnes/4.90 tonnes

So, if you want to be a lying bstart and use the upper EF fuel weight of 5 tonnes, and use the Su-27 lower fuel density and 9g only tanks then you can say the EF (5 tonnes) has more fuel than the Su-27, 4.9 tonnes! [In reality, there the EF has 86% the capacity of the Flanker.]

But, as we all know, the initial portions of any mission in which endurance/range is a factor do not involve 9g maneuvering, so the Flanker indeed has the full 11775 litres to use – which means the EF has 48% the fuel tank capacity.

Frontal cross-section only bettered by F-22 (written pre-F-35):

http://typhoon.starstreak.net/Eurofighter/structure.html

Ah… It was in a press release…. that means it must be trooo.

The problem is that drag is only a very small part of the (T-D)/m equation until near Vmax.

Thrust varies with speed due to inlet efficiency, so both variables in T – D are changing. Thats ok when considering small velocity deltas, but not significant accelerations.

Your right in that drag effects on acceleration start at 0 (at 0 m/s) and rise to 100% at Vmax, loosely rising on a quadratic curve.

But, broadly, the problem cannot be accurately described in a few lines on this forum.

I think you’re talking about irrelevance to drag, not acceleration, which will always be given by F/m.

The original source of the row on the first page was about speed and weight. Hence picking up on that.

Aside from that; F in this case is given by T – D.

[Which won’t make a big difference for similar aircraft, but could be substantial for dissimilar aircraft]

I used 2 x 90kN engines since you didn’t specify. I got a ~2% difference in drag (so about 1% in speed) but 13% difference in acceleration.

Yeah, I didn’t specify and don’t have the workbook to hand now. I can’t remember the numbers either.

KC-130J Harvest Hawk has the missile launch tubes built into the paratroop doors.

Yep, thats the kinda arrangement I’m on about…

But, given the oodles of cargo space and lift capacity wasted inside a normal cargo aircraft* – I’d be looking at some kinda onboard reload mechanism (or rather, cycling of the cells)… bit like the B-2 rotary launcher I suppose.

*Ideally, the basic system would plug into any Herk, Spartan, A400M, C-295 or similar, rather than just the gunships.