Why newer air to air missile all have smaller fin/wing?

[Vanessa1402]

As we all know, missile and aircraft alike turn using lift. The more lift they can generated, the more G they can pull and sustain. So in theory, bigger wing is better from maneuver aspect and big wing also help at high altitude.
But it seem like a common trend that newer missiles keep reduce their fin/wing size more and more.
AIM-54 and AIM-7 both have massive wing. AIM-120A get tiny wing and fin compared to its predecessor, AIM-120C reduce the fin size even further. This is not only happen with BVR missiles. It happen with short range WVR missile as well. AIM-132 ASRAAM has tiny fin compared to AIM-9A/B/C/D/E/M/L eventhough it also has no TVC. So what are the reason for this trend?. How can missile like AIM-132 and AIM-120C match the agility of their predecessor (let alone surpass them?)

 

[Ronny]

Possible that for missile designed in the 50-60s, their most dangerous targets are high and fast aircraft such as Mig-25, SR-71 so big wing is a requirement to operate in thin air. By contrast, modern fighters appear to operate mostly at medium altitude, so big wing isn't needed, reduce wing area can lead to lower drag and missile can go further at the cost of agility. I don't know why AIM-132 has such small fin though

 

[publiusr]

Nike Hercules have the biggest “fin-span?” —Not including BOMARC

 

[NMaude]

Nike Hercules have the biggest “fin-span?” —Not including BOMARC

That big fin-span is associated with the Nike booster-stage's tail-fins and those were discarded as soon as the booster burned and separated.

 

[Hobbes]

ASRAAM can maneuver at 50 g, which seems to indicate "loss of agility" is not an issue.

 

[sferrin]

Nike Hercules have the biggest “fin-span?” —Not including BOMARC

That big fin-span is associated with the Nike booster-stage's tail-fins and those were discarded as soon as the booster burned and separated.

Hercules' upper stage had huge fins too. SA-5 (S-200) Gammon had large fins as well. For thin air at high altitude as well.

 

[TomS]

This is outside of my comfort zone, but I wonder how much reduced fin size can be credited to improved autopilots and or the use of body lift and bank-to-turn steering for maneuvering. Old missiles were basically "bang-bang" with control surfaces either neutral or at full deflection. Now, autopilots can be much smarter about how much deflection to use, when to steer, etc.

 

[NMaude]

but I wonder how much reduced fin size can be credited to improved autopilots

This certainly would be the case.

Old missiles were basically "bang-bang" with control surfaces either neutral or at full deflection.

Not all of them especially the larger SAMs and AAMs, for example both the Sidewinder and the Sparrow used proportional deflection from the beginning.

 

[TMA1]

I think thrust vectoring is a large part as well as better solid fuels.

 

[Vanessa1402]

I think thrust vectoring is a large part as well as better solid fuels.

Neither AIM-120 or AIM-132 have thrust vector though

 

[iverson]

If current missiles reach higher speeds, they might get more lift from the body of the missile, with less need of wing lift.

 

[Manuducati]

The AIM-120 is a special case, the missile having to "fit inside" AIM-7 dimensions (including control surfaces) in order to be compatible with F-14, F-15 and F/A-18 Hornet fuselage (corner for the laters) recessed stations, and light enough to be mounted on F-16 wingtips. Then from the -C variant the control surfaces had to be small enough so six could be carried by the F-22 instead of four.
The next generation AIM-xxx will have similar limitations: 12 ft length (to go inside existing weapons bays) and its section will have to fit into a (12.8 inches iirc) square (potentially including folding surfaces), unless the Air Force is willing to diminish the number of missiles carried by its fighters (unlikely).

 

[zjz]

If current missiles reach higher speeds, they might get more lift from the body of the missile, with less need of wing lift.

Larger fins/wings area also contribute to higher drag.