LCA News and Discussions

SaiK · Post by **SaiK** » 19 Dec 2010 21:23

Can those LCA pod be converted to carry multiple rails launcher? so that it can take more R73s or Nags/brimstone. wing design/weight issues or already planned?

Singha · Post by **Singha** » 19 Dec 2010 21:41

which of the teen series has dual rail launchers for amraam or aim9x anyone know?

nachiket · Post by **nachiket** » 19 Dec 2010 21:56

SaiK · Post by **SaiK** » 19 Dec 2010 22:06

from wiki/f16
/corrected

del

sorry

nachiket · Post by **nachiket** » 19 Dec 2010 22:07

SaiK, Singha was asking about dual rail launchers for AMRAAM and AIM-9 missiles not bombs.

ashokpachori · Post by **ashokpachori** » 19 Dec 2010 22:53

Singha wrote:which of the teen series has dual rail launchers for amraam or aim9x anyone know?

F-15 uses such (dual rail) adapters for sidewinder.

SaiK · Post by **SaiK** » 20 Dec 2010 01:45

http://es.is.itt.com/LAU145A.htm
F-18 it is

SaiK · Post by **SaiK** » 20 Dec 2010 01:53

The lightweight ALARM weighs in at 584 lb, and is fired from ALARM specific rail launchers. This allows SEAD aircraft to carry a substantial load of weapons, this RAF Tornado IDS is carrying no less than 9 rounds on triple rail wing pylon launchers and three fuselage stations (BAe).

Surya · Post by **Surya** » 20 Dec 2010 02:48

Now thats a sexy rack

ramana · Post by **ramana** » 20 Dec 2010 08:31

Would like more info on the bomb trial. Looks like an accurate strike aircraft.

Singha · Post by **Singha** » 20 Dec 2010 10:37

per this pic, Tejas has 6 pylons on wing (3+3) and 2 below the fuselage. I have not seen anything like centerline pylon yet. also the Litening pod for strike will be on a chin pylon hopefully not a weapons pylon.

the outermost two pylons we can safely assume will mount the python5/R73
the innermost pylons will house the drop tanks for air defence and strike missions
that leaves 2 fuselage pylons and 2 wing pylons.

if we can come up with or purchase a dual weapon rail for the wings, we can have 6 BVR AAMs instead of 4 which is always better.
for DPSA strike missions it can carry 4 x 1000lb or more usually 4 x 500lb or 2x1000+2x500 imo.
for CAS missions within internal fuel range, it can carry 6 bombs and 2 R73
the Litening pod will be useful in a2g not just in targeting but in surveillance to locate targets and threats and damage assessment. it will also be useful to hunt helicopters passively at night, picking up their movements from above and launching guided aams.

if we integrate the KH59 as a deep strike missile, one fuselage pylon will go to its datalink pod, so maybe 4 x KH59, 2 x R73 and a single BVR AAM on the remaining fuselage pylon or leave it empty.

Rahul M · Post by **Rahul M** » 20 Dec 2010 10:38

which pic ?

shiv · Post by **shiv** » 20 Dec 2010 11:03

All air to air missiles have a shelf life and a carriage life - i.e. a limited number of hours that they can be carried on pylons. Having more pylons means that you are using up that life. In a prolonged conflict you have to strike a balance between using up the shelf life in flight hours where the missile is not used versus the need for missiles.

Any air force should be able to calculate the statistical probability of needing to use AAMs in a given action and from that calculate the number of missiles that can optimally be carried to ensure that more missiles than needed are not carried on hundreds of sorties.

Singha · Post by **Singha** » 20 Dec 2010 11:08

this pic

Singha · Post by **Singha** » 20 Dec 2010 11:26

small scale qualifications for IOC are fine. now they got to step up, populate all pylons and start some heavyweight missions with full representative payloads first to chitradurga then in pokhran, tezpur, leh, bagdogra, car nicobar to test weapons and sensors in all possible conditions. it also has to practice DACT and joint missions with all other IAF fighters, escort missions with phalcons/midas/MMS1 and ofcourse DACT with Singapore AF F_16s

a daily screaming pass along ORR at 300ft with full weapons by a quartet of Tejas wingtip to wingtip with lights flashing @ a fixed time would not be too bad either...keep the brf boys happy. let the world know there is a new sheriff in town and he doesnt believe much in arrest warrants and namby pamby stuff. shape up or leave town.

Rahul M · Post by **Rahul M** » 20 Dec 2010 11:31

Singha · Post by **Singha** » 20 Dec 2010 11:33

so there is no side by side fuselage station - the 200kg will be Litening. perhaps two bombs can be placed in tandem on the fuselage centerline - I hope so. 2 BVR aam though it drops down before firing safely may not be possible due to length limits (AAMs tend to be long things vs bombs)

The Mk2 with higher thrust and stronger bones can rectify this. the underside is flat - should be possible.

abhik · Post by **abhik** » 20 Dec 2010 11:54

Singha wrote:per this pic, Tejas has 6 pylons on wing (3+3) and 2 below the fuselage.

The only 2 below fuselage "pylon" AFAIK are the centerline(1)and the one for the pods.
The F-15E has an interesting arrangement for its numerous pylons. 1) it loads 2 AAMs and a large fuel tank on the same pylon and 2)it has pylons on its CFTs

abhik · Post by **abhik** » 20 Dec 2010 12:08

Here is an (model) lca from the early days-Fuel tanks on pylon no. 2,4 and 6; 2 bombs placed one after the other on no. 3 and 5.

I guess this sort of load out will not possible on the present aircraft.

abhik · Post by **abhik** » 20 Dec 2010 12:16

Also IAF Mig-21s with 'multi rails'(?).

Singha · Post by **Singha** » 20 Dec 2010 12:39

well time to start work on certain ideas then. the idea of a taller fuel pylon and a couple AAM fixed to the side seems interesting...(F15E style)..

suryag · Post by **suryag** » 20 Dec 2010 12:48

Why are drop tanks always hung, why cant they be put above the wing and dropped when all fuel is dumped into the wings. This way there would be no need to pump out from the drop tank to the wings, gravity will do the job.

krishnan · Post by **krishnan** » 20 Dec 2010 13:33

suryag wrote:Why are drop tanks always hung, why cant they be put above the wing and dropped when all fuel is dumped into the wings. This way there would be no need to pump out from the drop tank to the wings, gravity will do the job.

How are you gonna drop them? Invert the aircraft?

himanshugoswami · Post by **himanshugoswami** » 20 Dec 2010 13:38

suryag wrote:Why are drop tanks always hung, why cant they be put above the wing and dropped when all fuel is dumped into the wings. This way there would be no need to pump out from the drop tank to the wings, gravity will do the job.

would that not play havoc with the aerodynamics of the bird? and then, what happens when you need to jettison them? will you provide small rockets to make them fly clean off the bird?

shiv · Post by **shiv** » 20 Dec 2010 13:49

suryag wrote:Why are drop tanks always hung, why cant they be put above the wing and dropped when all fuel is dumped into the wings. This way there would be no need to pump out from the drop tank to the wings, gravity will do the job.

Sounds dangerous - although I think the BAC Lightning had overwing drop tanks.

When you "drop" a drop tank from above the wing - the drop tank will have to lift itself off, go behind the wing, miss the tailfin and then fall. That means that the drop tank will have to "fly" for a bit. If the tank has to be jettisoned when it is full or half full in an emergency it would be worse. I have no idea how they made the BAC Lightning's drop tank drop without hitting the tailplane or tailfin.

I found refs that say that the overwing tanks were "ferry tanks" in the Lightning, not drop tanks. That is more likely.

Lalmohan · Post by **Lalmohan** » 20 Dec 2010 14:01

^^^ and the starfighter had wing tip tanks, as did a number of other aircraft

abhik · Post by **abhik** » 20 Dec 2010 14:55

When you "drop" a drop tank from above the wing - the drop tank will have to lift itself off, go behind the wing, miss the tailfin and then fall. That means that the drop tank will have to "fly" for a bit. If the tank has to be jettisoned when it is full or half full in an emergency it would be worse.

Or go upside down and then drop them!!

Avinash Rav · Post by **Avinash Rav** » 20 Dec 2010 16:46

shiv wrote:
suryag wrote:Why are drop tanks always hung, why cant they be put above the wing and dropped when all fuel is dumped into the wings. This way there would be no need to pump out from the drop tank to the wings, gravity will do the job.

Sounds dangerous - although I think the BAC Lightning had overwing drop tanks.

Shiv, I was wondering what if the plane (with overwing drop tanks) had to fly upside down. I mean, it has to have a pump inside it to pump the fuel in this position. Else the turbine might flame out because of shortage of fuel.

So, my next question is, what advantage has the "overwing drop tanks" over "underwing drop tanks" ? In both these cases a pump is definitely needed....!!

krishnan · Post by **krishnan** » 20 Dec 2010 16:55

Only thing i can figure out is, it is easy to jettison them

Lalmohan · Post by **Lalmohan** » 20 Dec 2010 16:58

a fuel pump is always needed in a jet, and in any decent manoevring piston
(early Me109's used to cut out in inverted flight due to not having one and gravity not playing ball)
drop tanks don't directly feed the engine, they feed a wing and/or fuselage tank or tanks which flow through (eventually) to an engine

re jettissioning overwing tanks - an empty tank if released, or explosively detatched will be caught in the slip stream and quickly blown away before its had much time to drop downwards. the rear fins may be designed to help it do so. underwing tanks and stores run the risk of 'flying up' under the wing, so stores separation design over or underwing (i.e. gravity > aerodynamic up load) is quite an interesting engineering problem.

aditp · Post by **aditp** » 20 Dec 2010 17:19

^^^
All fighters in WWII had fuel pumps. None depended on gravity feed. In fact the Me-109 never faced fuel cutoff problem. The Diamler engine powering the aircraft was a pioneering unit with direct fuel injection (straight to the combustion chamber) via mechanical pump. On the other hand the Spitfires fuelled via carburettors could'nt engage the Me-109s in a sustained inverted dive, as the fuel would spill from the float chamber!

Lalmohan · Post by **Lalmohan** » 20 Dec 2010 17:19

sorry, my mistake, i meant it hte other way round

Singha · Post by **Singha** » 20 Dec 2010 17:34

whats the fundae behind bent wing of vought corsair ? vs straight wing like spitfire or me109. fw190 vs me109 which was superior?

ashokpachori · Post by **ashokpachori** » 20 Dec 2010 17:39

Usually the fuel in the drop tanks is consumed first, and only when all the fuel in the drop tanks has been used, the fuel selector is turned on the airplane's internal tanks.

Pilot always drains the drop tank first.

vina · Post by **vina** » 20 Dec 2010 17:41

On the other hand the Spitfires fuelled via carburettors could'nt engage the Me-109s in a sustained inverted dive, as the fuel would spill from the float chamber!

Oh.. The solution for that was rather simple.. It was invented by a Miss Shilling and the solution was called "Ms Shilling's Orifice"

.. Check out the wiki entry on that Ms Shilling's Orifice

shiv · Post by **shiv** » 20 Dec 2010 17:42

Lalmohan wrote:so stores separation design over or underwing (i.e. gravity > aerodynamic up load) is quite an interesting engineering problem.

Which seems to be why a bigger hoohah was made about drop tank dropping than bomb dropping or mijjile phyrring in Tejas.

Abhibhushan · Post by **Abhibhushan** » 20 Dec 2010 17:45

This is surely OT but since it is being discussed seriously...

In any tightly packed fighter, fuel is stored in many tanks distributed over the wings and the fuselage and also in additional 'drop tanks' or conformal additional tanks. Proper transfer of all the fuel in proper sequence into a 'collector' tank for a steady supply to the engine is therefore a design problem that must be solved. Some designers use (many) transfer pumps to solve the problem (e.g.Jaguar). Some others solve the problem more elegantly by differential pressurisation sequence of the fuel tanks (e.g. Gant and MiG21)

In all cases, in a jet engine, inverted flight is catered for. In a light piston engined aircraft that use carburettors, prolonged inverted flight may not be possible.

aditp · Post by **aditp** » 20 Dec 2010 17:47

...While not solving the problem fully, the restrictor, along with modifications to the needle valve, permitted pilots to perform quick negative g manoeuvres without loss of engine power, removing the annoying drawback the British fighters had had in comparison to the German Messerschmitt Bf 109 machine, which was equipped with fuel injection. Miss Shilling with a small team travelled around the countryside in early 1941 fitting the restrictors, giving priority to front-line units. By March 1941 the device had been installed throughout RAF Fighter Command. Officially named the 'R.A.E restrictor', the device was immensely popular with pilots, who affectionately named it 'Miss Shilling's orifice' or simply the 'Tilly orifice'.

This simple and elegant solution was only a stopgap: it did not permit an aeroplane to fly inverted for any length of time. The problems were not finally overcome until the introduction of Bendix and later Rolls Royce pressure carburettors in 1943.

Ms Shilling's Orifice couldnt withstand TFTA German injection.

Lalmohan · Post by **Lalmohan** » 20 Dec 2010 17:48

sorry, memory finally catching up
germans had fuel injection unlike brits (in begining)
then super charging
then turbo charging
then turbo-super-charging

the corsair (and Ju87 stuka) gull wings i think offer a couple of options
1. removing the main wing from prop wash and fuselage airflows, making it cleaner - lower drag, improved control responses(?)
2. 'cheaper' undercarriage clearance and also wing folding advantages

also wing anhedral and then dihedral offers other stability and flight mechanics advantages during turns

symontk · Post by **symontk** » 20 Dec 2010 19:47

shiv wrote:
suryag wrote:Why are drop tanks always hung, why cant they be put above the wing and dropped when all fuel is dumped into the wings. This way there would be no need to pump out from the drop tank to the wings, gravity will do the job.
Sounds dangerous - although I think the BAC Lightning had overwing drop tanks.

When you "drop" a drop tank from above the wing - the drop tank will have to lift itself off, go behind the wing, miss the tailfin and then fall. That means that the drop tank will have to "fly" for a bit. If the tank has to be jettisoned when it is full or half full in an emergency it would be worse. I have no idea how they made the BAC Lightning's drop tank drop without hitting the tailplane or tailfin.

I found refs that say that the overwing tanks were "ferry tanks" in the Lightning, not drop tanks. That is more likely.

Even if we have drop tanks or AA misslles over wing like Jaguar, can the LCA wing hold the additional load? I think the issue will be solved in MK2 by having more space for internal fuel and AA refueling system. Then no need of any drop tanks.