Forum: F-16 Design & Construction

Forum Veteran Joined: Apr 16, 2005 - 03:16 PM Posts: 800

Ok. But you have to be able to double the payload. For that it might maybe be possible to mount 2 ESTERs or 2 BRU-57s in a row.

Ideally a dual 2000lbs bomb rack would also be required. Like a derivative of the BRU-57.

I checked the dimensions quickly and I'm pretty sure that there would be enough clearance with the tank with 2 2000lbs JDAMs mounted next to it. I base myself on the fact that the 2000lbs JDAM has the same box size as the maverick, and the BRU-57 can carry the maverick.

http://www.edomtech.com/Products_files/image016.jpg

I also checked the dimensions of the SDB rack and it has pretty much the same box size as a 2000lbs JDAM. The rack + 4 bombs weight 1450lbs. Up to 8 SDBs could be carried per station eventually.

Those dual 2000lbs ejectors could have the ability to be mounted in tandem too.

For some weapons like most missiles the loadout could not be doubled however. Even though it might be possible I guess to mount in 2 mavericks in front and 2 bombs behind.

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Getting all that hardware mounted at 4/6 might be possible, but flying, maneuvering, ejecting, and jettisoning is another story completely. Some things just won't work, like Mavericks in front of bombs. The bombs won't be able to tolerate the rocket blast. Don't consider Mavericks at 4/6 anyway, as they will burn the tails and probably cause engine stalls due to plume ingestion. Tandem heavy weapon carriage has already been tried, unsuccessfully, as I already mentioned. 4500 lb of pylon, racks, and weapon just isn't likely to succeed at 4/6 due to wing, pylon, and rack strength.

I don't mean to be so negative, but until you've done this work, you just have no idea how difficult is integrate weapons onto an airplane. There are very many conflicting requirements to be met.

Forum Veteran Joined: Apr 16, 2005 - 03:16 PM Posts: 800

btw apparently there's a new rack now, IMER.. don't know it that would help

http://www.globalsecurity.org/military/ ... ms/mer.htm

Or maybe they could make a pylon that would have 4-6 ejectors already, it would be much more rigid.

mmhh..

Elite 1K Joined: May 26, 2005 - 08:39 PM Posts: 1496

johnwill wrote:

There are very many conflicting requirements to be met.

Well said. It's really hard to "min/max" the design of a modern fighter.

The IMER description did not mention additional stiffness, so it still needs that. MER flexibility shows up two ways, during transonic carriage and during ripple ejection. With some heavy stores at speeds above .85 mach an anti-symmettic low frequency pitch oscillation develops which the pilot feels as a lateral motion. Anti-symmetric means the left MER moves nose up while the right MER moves nose down. It's tolerable for a while, but not at all desireable. Ripple ejection means dropping some or all stores on the rack with a certain time interval between each of them. The ejector forces on the bombs are reacted by the MER, so it deflects due to those forces. The centerline racks feel an upward kick, while the side racks feel a kick up and sideways. So you get vertical and lateral motion in the MER. At certain ripple intervals, these motions resonate with the pylon and wing natural frequencies and bad things result, one of which is more lateral scatter in the bomb impact points. I realize today's smart weapons won't be dropped in ripples, but I wanted you to see how unexpected problems can happen.

The idea of a multi-bomb pylon appeals to me, and with the CFT opening up 4/6, maybe it could happen.

Forum Veteran Joined: Apr 16, 2005 - 03:16 PM Posts: 800

I was thinking, if they make this pylon or MER it might be used on the F-35 too I guess .

To get back to the issue of vibration and oscillation, it seems obvious that it would shake a lot, given how the MER is attached.

However, wouldn't it be possible to fix that problem. Here's a simple idea that I have thought of to try to correct the problem..

2 small rails would be attached at the front and at the back of the pylon. The MER would be modified to have rails that would fit on them. That would prevent any vertical and lateral movement it seems to me.

As for a possible dual 2000lbs ejector, 2 reinforcements could be added on each side of the rack one at the front one at the back, that would attach to the pylon. That should also reduce lateral and vertical movement.

Do you think something like that could help? Confused

Inbd shoulder station on a TER at stations 4/6 probably wouldn't be loaded. Release of a weapon could theoretically be into the fuselage.

If my memory serves me correctly original flight testing using a MER proved unsatisfactory. Rumor had it that the flex of the MER in certain flight parameters would sling a slick over the wing of the a/c. After seeing the CFTs it wouldn't surprise me if we don't see overwing fuel tanks and/or AIM-9/120s like the old Jaguar! A 4 station MER could work but again it you would have a flex problem.

Forum Veteran Joined: Apr 16, 2005 - 03:16 PM Posts: 800

Ok wait a minute.. there's no reason why the bombs have to be ejected on the sides.

On the rafale the bombs are ejected (or dropped don't know) vertically.

Here are some pictures:

3 weapons ejected vertically, the ejectors are staggered:
http://www.dassault-aviation.com/fr/defense.html
http://www.defesanet.com.br/rv/le_bourg ... fale_c.jpg

Here's an idea for the F-16.. make a dual launcher for 2000lbs bombs ( derivated of the BRU-57), have the ability to add another ejector in the middle ( the bombs would be staggered vertically and even possibly longitudinally like on the rafale).

And make a 6 launcher derivative. That sextuple would have a basic configuration with 4 ejectors, plus the ability to add 2 in the middle, so it could carry 4 1000lbs bombs or 6 smaller bombs.

That would solve all the problems.
- Stations 3 and 7 would be able to have 3 smaller weapons like GBU-12s/GBU-38s.. no problem of ejection with the tank.
- the rack would allow 2x2000lbs bombs on stations 4/6.
- the sextuple derivative could really carry 6 weapons on 4/6.

So that rack could possibly look like the drawing I made before, but with the possibility to add a third ejector in the middle for smaller weapons.

Forum Veteran Joined: Apr 16, 2005 - 03:16 PM Posts: 800

And here's an idea to reduce vibrations for the tank on stations 3/7.

A device would be attached at the back of the pylon and would be designed to avoid lateral and vertical movement of the tank. Hopefully that would avoid any flutter phenomenon.

The device would not be attached to the tank, so the tank would not have to be modified. It would just follow the contours of the tank to prevent any movement.

Two Cents

One thing to notice is they dont show how you will have any fuel transfer.
As far as I can see they would need some method to allow the fuel transfer from the modified 3&7pylon, to the 4& 6 pylon... Now the other interesting part is indication.
I am guessing with some of the newer systems we have an ability to measure the fuel levels in these modified tanks, in the same way that a 600 gal and the CFT's can be read.

One thing that made me laugh was the animation for the Air Rearming System...
Nice thought But ....
Call me crazy...
What happens when you don't have a new cart loaded into the pylon?
None of the information, and that includes their links addressed how to replace the ejector cartridge...

William G

Forum: F-16 Design & Construction

370gal tanks on stations 3 and 7..