Weird object on back of F/A-18F

We were at the Salinas Airshow last week and there were 2 F/A-18F's parked on the runway. We were able to get around and look at the back real close and found this on airframe 165802:




a bit closer


Now right next to it was airframe 165798 which did not have them:






So we have two airframes that are pretty close in production number that have a big difference. The question is what are they?

Countermeasures?

[edit on 10/3/08 by FredT]

reply to post by FredT


I'm not positive, but these look like flare/chaff ECM dispensers......

reply to post by habu71


Thats what I was wondering too, but I thought you usually found them on the lower portion of the airframe and they have a 25 degree bend to them as well.

Also why on one and not the other.

[edit on 10/3/08 by FredT]

I'll go along with...

Some form of countermeasures dispenser...

Originally posted by FredT


Also why on one and not the other.

Because VFA-122 (165798) is a replacement (training) squadron whereas VFA-211 (165802) is a fleet deployed (operations) squadron.



[edit on 3/10/2008 by Mirthful Me]

If it were a simple countermeasures dispenser, why offset at 25deg to the longitudinal axis of the aircraft?


Possibly a heat exchanger? (similar to the F-22, circulating fuel through the leading edges of the wings to keep them cool for IR signature reasons)

For this, the crossflow would induce additional mixing with the ambient flow, dispersing the hotter air quicker.... although with the engine exhausts being a few metres away, I don't see what significant effect the crossflow mixing would have on overall rear azimuthal IR signatures.


It could be a test item Fred, you happened to stumble across a frame the Navy are using for testing?



edit: If it were a countermeasures dispenser, and you were on full clockwise roll, chances are any released flare/chaff would impact the left 'vertical' fin.

I don't think it is a dispenser.

[edit on 3/10/08 by kilcoo316]

I'm willing to bet that it's part of the ALQ-124 (IDECM). It has the ALE-47 which controls chaff, flares, and decoys, as well as the ALE-50 decoys. The ALQ-124 was deployed in Iraqi Freedom, but I can't find any good pictures of the system, or of what any of the sensors look like. The one CGI picture I have of a Super Bug deploying an ALE-50 it does look like it is deployed off the top of the aft fuselage......

Obviously---chemtrail generators.

*ducks*
*runs, dodging rotten tomatoes*



Kidding. Really.

Another thing to notice is that those "openings", for lack of a better word, are hexagonal in shape and not round. Perhaps that's for RCS purposes? However why pay attention to the RCS given that this is in the exhaust and tail area, traditionally not a very LO region.

Fred, with your permission I'd like to post these images elsewhere and see if I can get a definite answer.

[edit on 4-10-2008 by WestPoint23]

Originally posted by WestPoint23
Fred, with your permission I'd like to post these images elsewhere and see if I can get a definite answer.

[edit on 4-10-2008 by WestPoint23]

Please do im pretty curious

Originally posted by Phage
Obviously---chemtrail generators.

*ducks*
*runs, dodging rotten tomatoes*

Kidding. Really.

ha, I am so going to send that to some chemtrail board! haha

I have never seen those things before on an F-18, it almost looks like they are photoshopped in, by the angle of those "things" compared to the angle of the tail section, but that's just me.

they are quite weird maybe it was a heat exhust of some kind, chaffs are normally lower and larger and tilted at more of an angle.

Originally posted by firepilot

ha, I am so going to send that to some chemtrail board! haha

Don't.
Please don't.

Odd...looks almost like tailpipes on a 68 GTO sort of.

I would suspect they are some kind of venting ducts for the engines, perahps a new design to the engines so they perform better. Or even dispensers that shoot out something to kill the exaust heat signature if other countermeasures are exausted during combat, a backup of sorts.

Looks kinda weird..whatever they are for.

Cheers!!!!

I've seen a thread on this before. It was a while ago but I think they are ducts for something. I doubt they're dispensers as the airflow between the fins would make safe dispension difficult - especially while manuvrering.

Here's one on display at Farnborough '06

Those don't look very aerodynamic - and they are right on top of the engines so I doubt countermeasures. The countermeasures don't protrude from supersonic aircraft. Very strange indeed although it's probably got a simple purpose for training or engine experimentation?

The AN/ALE-55 FOTD went into production in 2006 after tests to see if it could safely operate in the afterburner plume of the F/A-18s. These could be dispensers for the decoys. They're smaller, and fiber optic so they're more effective than the ALE-50s.

This is prob. just a stupid question....but does the second plane on the first top have a arrestor hook? (a pure land-based Hornet?).

Could that be the solution that the naval Hornet has the dispencer on top, and land-based have on the bottom?

Originally posted by Phoebus
This is prob. just a stupid question....but does the second plane on the first top have a arrestor hook? (a pure land-based Hornet?).

Could that be the solution that the naval Hornet has the dispencer on top, and land-based have on the bottom?

Only the Marines and Navy have Hornets and only the Navy has the Super Hornet, Marines always get the left overs and get the old stuff...lol
There is no land based only Hornet that I know of unless its in an advasary squadron or test pilot squadron and evan those have tailhooks.......FYI The F-15 has a tail hook for landing emergencies.

reply to post by Phoebus


It does its just not apparent from the angle of the picture.