F-14 low speed prowess vs Other Aircraft

Based on your vast knowledge of youTube videos ;)

Why are mods so provocative on this forum? You're here to prevent things from getting out of hand, not instigate things!

PS: I've been at many airshows in person, taken photos and recorded videos.

Well when you start using terms like 'butthurt' I figure a thread is just about done anyways...

Erm... you're saying he didn't purposely try to rile me up? Come on now, let's be objective here, and more importantly get back on topic.

Anyways, when did this turn into a F-14 vs F-15 thread? Seems off topic and you started the thread...

The thread is about the F-14's low speed prowess, which obviously means it will be compared with other aircraft, which is perfectly on topic - so says the OP ;)

Personally I'd like to know exactly why each plane is capable of what it is. While I can see why one could argue that the F-14 is aerodynamically superior to the F-15 and F-16, what surprises me is that it apparently overcomes the drastic weight difference.

No biggy it's all relative - you can overcome weight and drag with adequate thrust and lift.

3 very different designs - all achieve their design goals in different ways aerodynamically - the F-16 probably being the most radical (F-35/22 use some similar design concepts)

No biggy it's all relative - you can overcome weight and drag with adequate thrust and lift.

 

3 very different designs - all achieve their design goals in different ways aerodynamically - the F-16 probably being the most radical (F-35/22 use some similar design concepts)

Yep.

Also, let's not forget the F-18 which trades sustained maneuvering for extremely rapid instantaneous high alpha agility :)

In this video the F-14A executes a 360 deg min radius turn in ~20 sec with an entry speed of 325 mph (Mach 0.42) and accelerates to an exit speed of 450 mph (Mach 0.59) [4:58 min]:

Uj7WA5m2F-4

So a 360 in ~20 sec from a starting speed of Mach 0.42, that's mighty impressive.

No biggy it's all relative - you can overcome weight and drag with adequate thrust and lift.

Yep - F-4 is a beautiful case study of what enough thrust can help overcome.

Have you guys seen this video?

Have you guys seen this video?

 

Great find! I've seen excerpts, but never the video itself. Looks like 1974 given the prototype gunports (not vents, but the port itself) on the VF-124 aircraft.

One of the big surprises of the F-14 in it's early career was it's performance in the vertical. On paper, it seemed like it might lag behind the F-4 in climb ability while accelerating better in level flight. Reality proved to be the opposite, it was much better than the Phantom in the vertical, but only slightly faster in level acceleration from 250 kts to 500 kts (after which the Tomcat developed a bigger advantage).

It was a reminder of how performance can be difficult to fully appreciate with numbers alone (T/W ratio). What was found during the Tomcat's OpEval testing was much better operational performance in the vertical than the Phantom. The reason was that the Tomcat lost much less energy pitching up into the vertical and lost less airspeed in the climb because of it's better lift-drag ratio. As such, it could sustain a vertical climb with a lower starting airspeed, which proved to be a big real world advantage. It could start a climb at 350 knots and consistently vertically separate from an A-4 or F-5. The Phantom needed at least 450 knots to do the same. The Tomcat could also pitch around from the vertical with a lot less airspeed and performed much better at high AOA.

The Phantom had a few advantages against the F-14, mostly a better roll rate and it sustained higher speeds in military power alone, especially above 20,000 feet. Tomcats (F-14As) use their burners a bit more during ACM than Phantoms - one of the limitations of the TF30 is more than average thrust degradation at altitude, especially in military power and with slower airspeeds. One Tomcat pilot claimed: "The only thing the TF30 can reliably do in military power above 25,000' and below 250 knots is convert JP-5 into noise".

The benefits of the F110 were more noticeable operationally than the numbers might suggest. The TF30 was great in full afterburner below 10,000 feet (a VF-14 pilot called it a "beast"). But the aircraft certainly felt underpowered at higher altitudes without burner. The F110 was a HUGE operational improvement for loaded aircraft at middle to high altitudes, especially for casual operations (eg, climbing to altitude, accelerating from max conserve airspeeds, etc).

-Nick

Have you guys seen this video?

 

Yeah, posted it here a while ago along with some other very interesting videos: http://forums.eagle.ru/showthread.php?t=141451

Thanks :)

 

Are you still using rates instead of acceleration figures? :) Wondering considering the actual acceleration measurements of the F-14A & F-16C:

 

 

I'd use the actual acceleration figures, as that's from where the rates are calculated. The rates also make no sense at very low speed.

Of course, i use rates because they are more intuitive, and the difference isn't all that great. But, when doing actual computations i use both :)

 

 

 

The benefits of the F110 were more noticeable operationally than the numbers might suggest. The TF30 was great in full afterburner below 10,000 feet (a VF-14 pilot called it a "beast"). But the aircraft certainly felt underpowered at higher altitudes without burner. The F110 was a HUGE operational improvement for loaded aircraft at middle to high altitudes, especially for casual operations (eg, climbing to altitude, accelerating from max conserve airspeeds, etc).

 

-Nick

Pretty much this. Above angels 25, the PW's would hardly hold you airborne, let alone accelerate (in MIL power).

EDIT: looking again at those Su charts i posted, and playing with the google translate, i get the notion that both are sustained turns, just one in full AB and the other in full MIL power....... but..... can a Flanker really sustain more then 9g with 4 AAMs and over 10000lbs of fuel at 10000ft???

Pretty much this. Above angels 25, the PW's would hardly hold you airborne, let alone accelerate (in MIL power).

Although, if you load up an F-15C to ~50-55K lbs, the F100's also have a hard time accelerating above 25K and its best to climb in steps (I just tried this out).

I've heard that the GE engines in general (in both the Tomcat and Viper) are much better at altitude with lower airspeed. PW engines seem to want more airspeed to make thrust.

-Nick

The only comparisons you can make with real aircraft are the clean birds in-game.

Stores drag is quite excessive in-game. An eagle with two bags and eight missiles will happily go M1.6-1.8, and that performance is part of its air sovereignty mission. That doesn't mean you shouldn't climb in steps, but that's a schedule that pilots plan based on the aircraft's Ps curves, fuel flow, and desired time-to-distance.

LN may possibly deal with stores drag differently so it won't affect their aircraft.

The only comparisons you can make with real aircraft are the clean birds in-game.

 

Stores drag is quite excessive in-game. An eagle with two bags and eight missiles will happily go M1.6-1.8, and that performance is part of its air sovereignty mission. That doesn't mean you shouldn't climb in steps, but that's a schedule that pilots plan based on the aircraft's Ps curves, fuel flow, and desired time-to-distance.

 

LN may possibly deal with stores drag differently so it won't affect their aircraft.

Good to know, though it seems that the F-15C can still reach very high speeds with stores, including fuel tanks. I was surprised that it could reach M1.6+ with 3 fuel tanks. Plus, part of the acceleration/climb changes is the fact that thrust relative to mass really drops off with altitude. Engine thrust drops by ~ 50% by 20,000' and drag decreases considerably also, but mass is constant. It's no surprise that an aircraft operating at twice it's empty weight with with less than half of it's sea-level thrust would have underwhelming acceleration up in the stratosphere.

One nice characteristic of the F-14 was that all of is stores are conformal/semi-conformal in the center tunnel. Placing large stores in the center tunnel was chosen for drag benefits and the fuselage lift that resulted was unexpected. It was discovered during aerodynamic testing. Many Tomcat pilots would move to the ANG after retiring from the USN and fly the F-16C. One Tomcat pilot that I spoke to (via the Sunset forum several years ago) was flying Block 32 wide-mouth F-16Cs. He was impressed by the Viper's abilities, but surprised by how much performance deteriorated when they strapped on fuel tanks or ordinance. The Tomcat, in contrast, had little performance changes from it's stores.

-Nick

The F-14's stores between the engines are incredibly draggy, at least if the manual is correct. As you mentioned, the good thing is that up there, drag doesn't count as much. There are more effects than just drag when you add stores, the F-14 just seems to suffer less from such. Also, the F-16's intake isn't as good at recovering thrust as an F-14 or F-15, so I suspect those play a huge role.

The F-14's stores between the engines are incredibly draggy, at least if the manual is correct.

I actually got the opposite impression. At least relatively, the F-14A seams to have less penalty from stores then the F-15/16/18 or Su-27. With 8 AAMs, even the A still reaches mach 2.15 at 35+ kft (out of max 2.41+ clean) unlike the F-15 wich struggles to break through mach 2.0 with similar load (out of max 2.5 clean). The Su us even worse.

I think it has something to do with the conformal stores, or how much submerged the missiles were inside the funnel.

An F-15 will go pretty fast with stores onboard, but 'not permitted' AFAIK. Put it another way, they'll fly it M1.8 with two bags, those are about the value of the drag of all the AAMs put together ( ... minus pylons of course :) )

Conformal stores help, and both the F-15 and F-14 use them. Drag index of F-15 stores is pretty small. Drag index of F-14 stores is relatively quite large, but also realize the F-14 changes its wing sweep to drop overall drag to begin with. In other words, it's probably a bit beyond trying to pin it on any single thing.

In other words, it's probably a bit beyond trying to pin it on any single thing.

Probably so :)

Makes me wonder why they never came up with some less draggy solution for the Sidewinders though :confused:

I mean, those Sparrows could depending on station and plane go from 25% to over 75% recessed.

Sidewinders need to lock-on before launch, and a relatively wide FoV helps :)

The draggiest part about the sidewinder, IMHO, is the pylon it's attached to.

Sidewinders need to lock-on before launch, and a relatively wide FoV helps :)

 

The draggiest part about the sidewinder, IMHO, is the pylon it's attached to.

Good point about the seeker, i never thought of it.

Why do the drag indexes on the winders are then often larger (by quite the margin) then the ones for AMRAAMs and Sparrows (in the store managers in the manuals)?

EDIT: because of the adapter/pylon?

Good point about the seeker, i never thought of it.

Why do the drag indexes on the winders are then often larger (by quite the margin) then the ones for AMRAAMs and Sparrows (in the store managers in the manuals)? EDIT: because of the adapter/pylon?

For which plane and for which station? E.g. on the F-15's, both can be carried under the wings using the same pylon so it's probably not the pylon? Maybe due to the blunt seeker head of the Sidewinder (vs the thicker, but more aerodynamic AMRAAM I guess but I'm no aerodynamics expert)?

An F-15 will go pretty fast with stores onboard, but 'not permitted' AFAIK. Put it another way, they'll fly it M1.8 with two bags, those are about the value of the drag of all the AAMs put together ( ... minus pylons of course :) )

 

Conformal stores help, and both the F-15 and F-14 use them. Drag index of F-15 stores is pretty small. Drag index of F-14 stores is relatively quite large, but also realize the F-14 changes its wing sweep to drop overall drag to begin with. In other words, it's probably a bit beyond trying to pin it on any single thing.

How could wing sweep explain it? The F-14 isn't limited to wing sweep with stores only ;) Thus it can only really be that the F-14 suffers a smaller drag penalty from its stores, something which is evident looking at the speed difference at all altitudes.

I actually got the opposite impression. At least relatively, the F-14A seams to have less penalty from stores then the F-15/16/18 or Su-27. With 8 AAMs, even the A still reaches mach 2.15 at 35+ kft (out of max 2.41+ clean) unlike the F-15 wich struggles to break through mach 2.0 with similar load (out of max 2.5 clean). The Su us even worse.

 

I think it has something to do with the conformal stores, or how much submerged the missiles were inside the funnel.

Drag will also depend on flight regime. Around transonic speeds the constriction in area in the tunnel between the engines when filled with weapons could lead to earlier formation of shockwaves which could lead to big drag hits.

Good point about the seeker, i never thought of it.

Why do the drag indexes on the winders are then often larger (by quite the margin) then the ones for AMRAAMs and Sparrows (in the store managers in the manuals)?

 

EDIT: because of the adapter/pylon?

The sharper nose on the MRM's should help with drag at high speeds, perhaps having the wings on the missiles further back as well.