Swing Wings: Yea or Neah?

[BOB URZ]

Why have most newer fighter designs not used swing wings?
It seems in the US, the F14 and F111 were the last to go with
swing wings. It seems the major reasons for using them is having the
best of both worlds in wing loading at both low and high speeds.

Why have the newer designs avoided them? Maintenance?
Weight? Cost?

Also, most newer fighter designs use twin tails canted out from
perpendicular. Is there a reason this is better than straight
dual perpendicular tails?


Bob




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[The Enlightenment]

BOB URZ > wrote in message >...
> Why have most newer fighter designs not used swing wings?
> It seems in the US, the F14 and F111 were the last to go with
> swing wings. It seems the major reasons for using them is having the
> best of both worlds in wing loading at both low and high speeds.
>
> Why have the newer designs avoided them? Maintenance?
> Weight? Cost?

From what I can see mostly maintainance. Advances in engines: they
are both more fuel efficient, lighter and more powerfull for the same
size means that performance such as take of run, range and top speed
can be achieved without resorting to the complexity of swing wings and
the space and weight liberated can best be used to carry more fuel. I
note also aerodynamics such as strakes and leading edge extensions
have also helped as have reductions in airframe weight.

Still the low wind gust response of an Panavia Tornado with wings back
at low level penetration is much better than an F15E but low level
penetration is nuts accoding to the USAF.



>
> Also, most newer fighter designs use twin tails canted out from
> perpendicular. Is there a reason this is better than straight
> dual perpendicular tails?

Probably to get them in to clean airflow at high angle of attacks.

>
>
> Bob
>
>
>
>
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[Jim Doyle]

"The Enlightenment" > wrote in message
m...

<snip>

> Still the low wind gust response of an Panavia Tornado with wings back
> at low level penetration is much better than an F15E but low level
> penetration is nuts accoding to the USAF.


So that's why they leave it to the British?! :o)

Jim

[Thomas J. Paladino Jr.]

"BOB URZ" > wrote in message
...
> Why have most newer fighter designs not used swing wings?
> It seems in the US, the F14 and F111 were the last to go with
> swing wings. It seems the major reasons for using them is having the
> best of both worlds in wing loading at both low and high speeds.
>

....don't forget the B-1

> Why have the newer designs avoided them? Maintenance?
> Weight? Cost?
>

It's probably a combination of all three, though someone also pointed out
that engine efficiency has a lot to do with it as well. Newer engines are
indeed more versatile in their application of power, and I would probably
add that aerodynamics have come a long way as well.

That is not to say that there is no benefit at all in having a swing-wing,
but the advantage is minimized by these advances to a point that it no
longer becomes cost effective to incorporate variable geometry into a modern
design.

However, if I remember correctly, I did see some designs for a new SST
concept that utilized varible geometry wings. Not much came of it though, at
least I dont think.

> Also, most newer fighter designs use twin tails canted out from
> perpendicular. Is there a reason this is better than straight
> dual perpendicular tails?

That has more to do with steath than anything else. 90-degree angles are a
major no-no in stealth design. So simply canting the tail surfaces inward or
outward can greatly reduce a radar signature. I believe that this was first
discovered on the SR-71; the engineers lowered its signature by something
like 30% or so just by giving it inward canted stabilizers.


>
>
> Bob
>
>
>
>
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[breyfogle]

The swing wing mechanism adds ALOT of weight, the smaller the airframe the
larger the percentage weight gain. On both F14s and F111s the tradeoff to
optimum performance was considered acceptable in order to acheive both good
high speed performance (usually requiring a small wing) and good low speed
landing performance (large wing). B-1s made the same design choice for the
same reason. Fighters generally are optimised for maximum performance and
minimum weight and therefore can not justify carrying the extra weight of a
swing wing just to gain a lower landing approach speed.


"BOB URZ" > wrote in message
...
> Why have most newer fighter designs not used swing wings?
> It seems in the US, the F14 and F111 were the last to go with
> swing wings. It seems the major reasons for using them is having the
> best of both worlds in wing loading at both low and high speeds.
>
> Why have the newer designs avoided them? Maintenance?
> Weight? Cost?
>
> Also, most newer fighter designs use twin tails canted out from
> perpendicular. Is there a reason this is better than straight
> dual perpendicular tails?
>
>
> Bob
>
>
>
>
> -----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
> http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
> -----== Over 100,000 Newsgroups - 19 Different Servers! =-----

[Nemo l'ancien]

Jim Doyle a écrit :

> "The Enlightenment" > wrote in message
> m...
>
> <snip>
>
>>Still the low wind gust response of an Panavia Tornado with wings back
>>at low level penetration is much better than an F15E but low level
>>penetration is nuts accoding to the USAF.
>
>
>
> So that's why they leave it to the British?! :o)
>
> Jim
>
>
B'cause they, the US, have no more balls...

[Orval Fairbairn]

In article >,
Nemo l'ancien > wrote:

> Jim Doyle a écrit :
>
> > "The Enlightenment" > wrote in message
> > m...
> >
> > <snip>
> >
> >>Still the low wind gust response of an Panavia Tornado with wings back
> >>at low level penetration is much better than an F15E but low level
> >>penetration is nuts accoding to the USAF.
> >
> >
> >
> > So that's why they leave it to the British?! :o)
> >
> > Jim
> >
> >
> B'cause they, the US, have no more balls...
>

No, it is because, with stealth and PGMs there is really no longer a
need for low-level penetration. Brains over balls every time!

[Felger Carbon]

"Thomas J. Paladino Jr." > wrote in message
. ..
>
> However, if I remember correctly, I did see some designs for a new
SST
> concept that utilized varible geometry wings. Not much came of it
though, at
> least I dont think.

That's the now-ancient Boeing SST proposal. Boeing's engineers had
to tell management the fuselage could carry the swing-wing mechanism
or passengers, but not both. ;-(

[Jeb Hoge]

"Thomas J. Paladino Jr." > wrote in message >...
> "BOB URZ" > wrote in message
> ...

> > Also, most newer fighter designs use twin tails canted out from
> > perpendicular. Is there a reason this is better than straight
> > dual perpendicular tails?
>
> That has more to do with steath than anything else. 90-degree angles are a
> major no-no in stealth design. So simply canting the tail surfaces inward or
> outward can greatly reduce a radar signature. I believe that this was first
> discovered on the SR-71; the engineers lowered its signature by something
> like 30% or so just by giving it inward canted stabilizers.

I seem to recall that high-alpha directional stability also is
improved. That had a lot to do with the tailplane placement on the
Hornet...a little further forward and canted outward, so when it's
doing its slow, nose-high thing, the tailplanes still are effective.
I would imagine that that's an issue with the Raptor, too.

[M]

"breyfogle" > >

> The swing wing mechanism adds ALOT of weight, the smaller the airframe the
> larger the percentage weight gain. On both F14s and F111s the tradeoff to
> optimum performance was considered acceptable in order to acheive both good
> high speed performance (usually requiring a small wing) and good low speed
> landing performance (large wing).

I'd think that low-level high-speed performance was also an
important design consideration. Or, at least, it was found
useful for the low-level penetration missions that became the
primary tasks of F-111 and B-1B during the cold war.

MiG-23 is an interesting case. It's a relatively light
fighter with swing wings. Any comments on why MiG chose
such a design? Hardly just for STOL, although the Soviets
valued rough&short strip ability much more than the US
(MiG-29 perhaps as a prime exampole). Btw, 23 is very
fast on the deck, fastest of them all, I think.

I'd suspect that the design considerations behind MiG-23/27
could have been rather similar to those of the somewhat
heavier interceptor/strike Tornado.

[Nele VII]

M <*@*.*> wrote in message >...
>"breyfogle" > >
>
>MiG-23 is an interesting case. It's a relatively light
>fighter with swing wings. Any comments on why MiG chose
>such a design? Hardly just for STOL, although the Soviets
>valued rough&short strip ability much more than the US
>(MiG-29 perhaps as a prime exampole). Btw, 23 is very
>fast on the deck, fastest of them all, I think.

Fast AND agile. Syrian 23M and ML models were better to fo fight or chase
with F-16 at the deck. Medium sweep gave good 16 degrees/sec sustained (ML
excellent 18 degrees, MLD has a lower medium sweep and can go to 19 with
less buffeting) turn rate with missiles onboard- remember R-23/24 are HUGE
missiles, and R-60 M(?) are carried in quartet on ML! If it turned against
them, they would sweep back the wings, increase wing loading and went to a
low-level smooth high-speed ride, while Israeli pilots (F-16A, F-15A) were
banging their helmets on canopies due to gusts of Golan. MiG-23 has no
ailerons, it uses wing spoilers and stabilators for roll that is quite
snappy-just like one of Tornado.
>
>I'd suspect that the design considerations behind MiG-23/27
>could have been rather similar to those of the somewhat
>heavier interceptor/strike Tornado.

Well, Tornado -looks- heavier, but it actually of the simmilar size. It has
higher wing loading and less powerful engine(s), especially when compared to
MiG-23 MLD with Tumanskii R-35 engine (modified, lightened,
dorabu'tanyj-"reworked"). Tornado has also quite poor T/W ratio for a
dogfigter-remember picture of Tornado escorting Tu-95 Bear at altitude with
wings swept forward and one burner lit!
>
MiG-23ML is a good fighter. It has just been piloted by poor airmen. It can
also takeoff and land with full sweep and is used in Russian "Aggressor"
squadron (MLA/MLD, the first one being interceptor) simulating various US
adversaries like Kfir C1 with clipped canards (US "F-21") had emulated
MiG-23S (export version, MiG-21 avionics). MLD at medium sweep sometimes
emulates F-15 in dogfigts, having simmilar horizontal performance (cut
strakes and reduced sweep did the trick)! MiG-29U emulates F-16A.


--

Nele

NULLA ROSA SINE SPINA

[Bill and Susan Maddux]

It seems in the US, the F14 and F111 were the last to go with( you forgot
the B-1) I hate to admit it but I worked these pigs, and they had more
hydralic leaks on the wings than the B-52s.

Bill Maddux

[Jeff Crowell]

Nele VII wrote:
> Fast AND agile. Syrian 23M and ML models were better to fo fight or chase
> with F-16 at the deck. Medium sweep gave good 16 degrees/sec sustained (ML
> excellent 18 degrees, MLD has a lower medium sweep and can go to 19 with
> less buffeting) turn rate with missiles onboard- remember R-23/24 are HUGE
> missiles, and R-60 M(?) are carried in quartet on ML! If it turned against
> them, they would sweep back the wings, increase wing loading and went to a
> low-level smooth high-speed ride, while Israeli pilots (F-16A, F-15A) were
> banging their helmets on canopies due to gusts of Golan. MiG-23 has no
> ailerons, it uses wing spoilers and stabilators for roll that is quite
> snappy-just like one of Tornado.

There were drawbacks to the Flogger, though. Or at least so we
were briefed. I personally never turned 'n burned against one, but
the guys who did said it was so. The wing sweep mechanism on
the MiG-23 was limited to only 2.5G, at which piit it locked up.
If you put the press on a Flogger, you could drive him out of his
optimum wing angle very quickly. If he was never able to unload
to 2.5G or less, he could not change his wing angle and you had
your kill.

Also, you mention HUGE missiles... let's just imagine the bleed
rate if you start an angles fight carrying all that drag.

Due credit to Ed, a lot of guys would not bother to slow down for
the angles fight anyway.


Jeff

[Nele VII]

Jeff Crowell wrote in message ...
>Nele VII wrote:
>> Fast AND agile. Syrian 23M and ML models were better to fo fight or chase
>> with F-16 at the deck. Medium sweep gave good 16 degrees/sec sustained
(ML
>> excellent 18 degrees, MLD has a lower medium sweep and can go to 19 with
>> less buffeting) turn rate with missiles onboard- remember R-23/24 are
HUGE
>> missiles, and R-60 M(?) are carried in quartet on ML! If it turned
against
>> them, they would sweep back the wings, increase wing loading and went to
a
>> low-level smooth high-speed ride, while Israeli pilots (F-16A, F-15A)
were
>> banging their helmets on canopies due to gusts of Golan. MiG-23 has no
>> ailerons, it uses wing spoilers and stabilators for roll that is quite
>> snappy-just like one of Tornado.
>
>There were drawbacks to the Flogger, though. Or at least so we
>were briefed. I personally never turned 'n burned against one, but
>the guys who did said it was so. The wing sweep mechanism on
>the MiG-23 was limited to only 2.5G, at which piit it locked up.
>If you put the press on a Flogger, you could drive him out of his
>optimum wing angle very quickly. If he was never able to unload
>to 2.5G or less, he could not change his wing angle and you had
>your kill.
>
>Also, you mention HUGE missiles... let's just imagine the bleed
>rate if you start an angles fight carrying all that drag.
>
>Due credit to Ed, a lot of guys would not bother to slow down for
>the angles fight anyway.
>
>
>Jeff
>
>
Hm. I am not a pilot, but I know this-there's no aircraft without the
drawback. You can't roll F-15 a couple 360'es w/out some loading, or one
will be "punished" with inertia-roll coupling (interestingly, MiG-21 shares
the same "drawback", but not to the same amount). You MUST NOT roll an F-4
with it (more or less). You can't slow down the f-111 with full wing sweep
without loosing it... shall I go on? It is all up to the driver. If You have
a fruitcake in the cockpit, it does not matter what he/she flies!

Honestly, I thought that there's much lower g limit on '23 sweep change; I
also don't know how fast it can change the wingsweep (MLD migh be better
than M/MF/ML?).

My bottom line is that MiG-23 is not a bad airplane, but was prone to be
piloted by bad pilots...

--

Nele

NULLA ROSA SINE SPINA