J-15 carrier-borne fighter thread

Brumby

Major
But still for the first time (at least since some time) the J-15D in grey ... and IMO it is clearly a J-15D and not a J-15S

View attachment 56285

What is still missing are the jamming pods. Similarly, Growlers without the ALQ-99 pods are just Super Hornets.

Any body knows what is happening with the jamming pods? I have not seen a picture of one.
 
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Insignius

Junior Member
KG-800s (those have been seen onboard JH-7A and H-6Js) are the newest Chinese jamming pods. They should suffice for time being.
 

Brumby

Major
In the video 0:58, the J15 took off from extended position of 190m in 7 seconds, achieving approximate acceleration of 8m/s² and velocity of 200 kmph off the jump.
(Su33 stall speed is about 250kmph). Since the ski jump is angled at about 14°, Horizontal V is 190kmph and Vertical V is 50kmph. Vertical V is used as a safety against sink rate until target lift is achieved.

Considering rolling resistance and drag to be nominally about 10% at lower speeds, T/W is about 0.9. If thrust is assumed to be 26 tons, then TOW is 29 tons which means its carrying a full tank of gas with 2xMraam + 2xSraam.

You are more mathematically inclined and competent than me on this subject. There is a technical paper "CARRIER SUITABILITY OF LAND-BASED AIRCRAFT" which you can google.

In that paper it goes onto a lot more mathematical calculations on the issue.

upload_2019-12-31_9-56-36.png

upload_2019-12-31_9-57-1.png

Maybe you can make more sense out of it than I can.
 

Brumby

Major
KG-800s (those have been seen onboard JH-7A and H-6Js) are the newest Chinese jamming pods. They should suffice for time being.
Those are for self protection. Dedicated jamming platforms have big size jamming pods in order to conduct standoff jamming. They require a lot of power and cooling.
 

Bhurki

Junior Member
Registered Member
You are more mathematically inclined and competent than me on this subject. There is a technical paper "CARRIER SUITABILITY OF LAND-BASED AIRCRAFT" which you can google.

In that paper it goes onto a lot more mathematical calculations on the issue.

View attachment 56286

View attachment 56287

Maybe you can make more sense out of it than I can.
Don't get caught up in the jargon. Most of extra calculations they've done end up being nominal additions of 1-2%. Thats the reason I took a fat 10% cushion initially to absorb any unknown factors ( decrease in energy due rolling friction and drag, increase in energy due to lift and on deck wind speed).
The fact that they assume T/W as 0.89, the same as i arrived at, means Mtow can be 29 tons(J15) from (140+47)m launch point as long as windspeed is 20knots.
From (68+47)m at 20kn, T/W required will be about 1.05 giving Mtow of about 24-25 tons. There will be assured dip in trajectory( depressed path) for about 3-4 seconds when launching from forward section.
 

by78

General
Drone view.

(1280x720)
49303173851_d2b65ba01a_o_d.jpg
 

Brumby

Major
Don't get caught up in the jargon. Most of extra calculations they've done end up being nominal additions of 1-2%. Thats the reason I took a fat 10% cushion initially to absorb any unknown factors ( decrease in energy due rolling friction and drag, increase in energy due to lift and on deck wind speed).
The fact that they assume T/W as 0.89, the same as i arrived at, means Mtow can be 29 tons(J15) from (140+47)m launch point as long as windspeed is 20knots.
From (68+47)m at 20kn, T/W required will be about 1.05 giving Mtow of about 24-25 tons. There will be assured dip in trajectory( depressed path) for about 3-4 seconds when launching from forward section.
Why are you assuming (140 + 47) m and not (68 + 47) m as the launch point distance? What is the end speed based on MTOW of 29 tons?
 

Totoro

Major
VIP Professional
I did a similar calculation years ago but drag (rolling being more of a factor than air resistance at those speeds) amounted to no more than 5%.
Big difference was thrust to weight ratio. I went with 80% of uninstalled static sl thrust, as that seems to be the average for similar planes when they actually have engines installed. As the plane goes faster, thrust slowly rises.

That would mean 245*0.8 = little under 200 kn of thrust.
 
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