Lockheed develops rack to make F-35A/C a six-shooter

F-35 Armament, fuel tanks, internal and external hardpoints, loadouts, and other stores.
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swiss

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Unread post04 Jun 2019, 16:40

sprstdlyscottsmn wrote:What about fuel fraction? We are talking about two ~190lb missiles and two ~150lb pylons on a ~50,000lb plane. Why would that be expected to have a meaningful impact to fuel fraction? The six internal ~350lb missiles and two ~500lb adapters (?) didn't make you ask this question did they?


I mean will have the additional drag from the 2 missiles and pylons increase the fuel consumption. Sorry spurts English is not my mother tongue.
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Unread post04 Jun 2019, 16:45

sprstdlyscottsmn wrote:The AIM-9X on the F-35 is going to generate significantly more drag than on an F-16 (remember, AIM-120s occupy the tip stations so Sidewinders are on pylons) because of the toed out canted pylons.


IIRC the 9x pylons on the F-35 are canted to the side and not toed-out like on the F-18E/F.

The pylon itself looks to be actually better aerodynamically than the F-16s.

Here is the original 9x pylon for the F-35, note the blunt nose.

F-35wingtipLAU-148AextRailLauncherAIM-9Xsidewinder.jpg


Now, here is the new F-35 9x pylon. Note that the leading edges are knife-like instead of blunt. Next to it is an F-16 pylon for comparison.

capture3.png
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sprstdlyscottsmn

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Unread post04 Jun 2019, 17:33

swiss wrote:
sprstdlyscottsmn wrote:What about fuel fraction? We are talking about two ~190lb missiles and two ~150lb pylons on a ~50,000lb plane. Why would that be expected to have a meaningful impact to fuel fraction? The six internal ~350lb missiles and two ~500lb adapters (?) didn't make you ask this question did they?


I mean will have the additional drag from the 2 missiles and pylons increase the fuel consumption. Sorry spurts English is not my mother tongue.

Okay, that makes more sense. No the impact to fuel consumption should not be too great. Fuel fraction is the ratio of fuel to gross weight. And don't worry, your English is better than my anything else, you just used the wrong term for the question you had. It happens.
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disconnectedradical

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Unread post04 Jun 2019, 17:37

sprstdlyscottsmn wrote:I honestly expect the AIM-9X external will raise the front sector RCS to a whopping 0.0005-0.001m^2. Between these statements about improved survivability, the double canted pylon, and the fact that a clean F-35 with surface damage met/exceeded the RCS target of 0.0005m^2 (IIRC, to the F-22s 0.0001)... I just don't see the external carriage as an RCS issue.


I think not. AIM-9X itself has no LO shaping and will have bigger RCS than clean F-35. It doesn't matter if the pylon is canted, look at those perpendicular angles. And look at how perpendicular the control surface of the AIM-9 is. That's NOT good for stealth, and especially at lower frequencies those pylons will be bigger problem for RCS. At certain frequencies small protrusions can make big RCS impacts. Sure, RCS will still be better than Super Hornet or 4.5 gen fighters but it's not ideal.

They really need to fund an ejector launched version of AIM-9X so it can take them internally. That shouldn't be hard. What is the hold up?
Last edited by disconnectedradical on 04 Jun 2019, 18:35, edited 2 times in total.
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Unread post04 Jun 2019, 17:41

SpudmanWP wrote:
IIRC the 9x pylons on the F-35 are canted to the side and not toed-out like on the F-18E/F.

Alright Spud, I was pretty sure about it but your post made me double check.

I see pictures like below and it seems "obvious" that even with perspective the pylons are toed out.

5c65c522598e235da94d31d3-750-375.jpg


To be sure, I looked for shots from below. What do you know? You are right.

2012 Feb F-35A External Weapons Carriage 2.jpg


They are canted down, but not toed-out. The drag penalty will not be as bad as I figured.
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swiss

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Unread post04 Jun 2019, 18:01

sprstdlyscottsmn wrote:
swiss wrote:
sprstdlyscottsmn wrote:What about fuel fraction? We are talking about two ~190lb missiles and two ~150lb pylons on a ~50,000lb plane. Why would that be expected to have a meaningful impact to fuel fraction? The six internal ~350lb missiles and two ~500lb adapters (?) didn't make you ask this question did they?


I mean will have the additional drag from the 2 missiles and pylons increase the fuel consumption. Sorry spurts English is not my mother tongue.

Okay, that makes more sense. No the impact to fuel consumption should not be too great. Fuel fraction is the ratio of fuel to gross weight. And don't worry, your English is better than my anything else, you just used the wrong term for the question you had. It happens.


Thanks for your answer. So two external 9x should have a small impact on Drag, fuel consumption and frontal RCS for the F-35.

Problem is, here are many technical words and shortcuts i have to google first. :wink:
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Unread post04 Jun 2019, 19:40

disconnectedradical wrote:
sprstdlyscottsmn wrote:I honestly expect the AIM-9X external will raise the front sector RCS to a whopping 0.0005-0.001m^2. Between these statements about improved survivability, the double canted pylon, and the fact that a clean F-35 with surface damage met/exceeded the RCS target of 0.0005m^2 (IIRC, to the F-22s 0.0001)... I just don't see the external carriage as an RCS issue.


I think not. AIM-9X itself has no LO shaping and will have bigger RCS than clean F-35. It doesn't matter if the pylon is canted, look at those perpendicular angles. And look at how perpendicular the control surface of the AIM-9 is. That's NOT good for stealth, and especially at lower frequencies those pylons will be bigger problem for RCS. At certain frequencies small protrusions can make big RCS impacts. Sure, RCS will still be better than Super Hornet or 4.5 gen fighters but it's not ideal.

They really need to fund an ejector launched version of AIM-9X so it can take them internally. That shouldn't be hard. What is the hold up?


What's the hold up? They don't think they need it now. The experience at Red Flag indicates that stealth, enhanced situational awareness, and an AMRAAM only combat load is more than adequate to deal with the current threat.

I really think if it was a priority that the AF could develop the F-35 into an air superiority platform that is only outmatched by the F-22. Once the F-35 is able to carry six AAMs internally it might make sense to integrate a rail launched HOBS AAM as well options for AMRAAMs on the external pylons.
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Unread post04 Jun 2019, 19:46

blain wrote:if it was a priority that the AF could develop the F-35 into an air superiority platform that is only outmatched by the F-22
The JPO has already said that it is.
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Unread post04 Jun 2019, 22:15

SpudmanWP wrote:
blain wrote:if it was a priority that the AF could develop the F-35 into an air superiority platform that is only outmatched by the F-22
The JPO has already said that it is.


What a priority? Carrying six AAMs internally? Internal launched AIM-9X? Or using the F-35 to replace legacy air superiority planforms?
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Unread post04 Jun 2019, 22:20

blain wrote:
What a priority? Carrying six AAMs internally? Internal launched AIM-9X? Or using the F-35 to replace legacy air superiority planforms?

That it is already only second to the F-22 in Air to Air.
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Unread post05 Jun 2019, 00:52

If AIM-9X carriage is important it's surprising to me that they haven't tried to modify the AIM-9X to make it or its carriage more stealthy. Setting the fins at 60, 120, 180, 240 degree spacing, a truncated pyramid cross-section for the body and RAM. For carriage options either carrying them semi-submerged on a pylon mounted rail or within a faceted stealthy pod. Would assume the pod would have a fly-thru nose section that could be replaced if used.
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Unread post05 Jun 2019, 01:14

The NATOPS for the f-16 has a good drag Index. If anyone wants to do a aim9 on a station, other than the wingtip and how that compares. I don't know if the FA-18 NATOPS is as good.
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Unread post05 Jun 2019, 01:34

wolfpak wrote:If AIM-9X carriage is important it's surprising to me that they haven't tried to modify the AIM-9X to make it or its carriage more stealthy. Setting the fins at 60, 120, 180, 240 degree spacing, a truncated pyramid cross-section for the body and RAM. For carriage options either carrying them semi-submerged on a pylon mounted rail or within a faceted stealthy pod. Would assume the pod would have a fly-thru nose section that could be replaced if used.



My guess is short them the external AIM-9X's have a small impact on the F-35's overall RCS. While, long-term more capable and advanced Air to Air Missiles are in development. Which, will allow the F-35 both greater reach and in larger numbers. (internally)
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Unread post05 Jun 2019, 06:37

It's safe to assume that the JPO and armed services have a pretty. good idea of how extefnal AIM-9X..carriage impacts the F-35's RCS. They also have the latest intelligence on enemy radar capabilities. While nothing is certain, the decision on whether to carry external Sidewinders will be an informed one. Perhaps this played a part in the shelving of plans to develop a mechanism for internal carriage as not being ' worth the squeeze'.
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Unread post05 Jun 2019, 07:36

Between LREW, MSDM, ErWn and SACM, I can't see the Air Force spending the time and effort
to integrate AIM-9X, a missile at the limits of its growth potential, internally.

Since it's unclear if the other efforts with be exportable, that would leave it up to the partners.
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