And you thought the Tomcat we had was great

[JetStar]

http://foxtrotalpha.jalopnik.com/top-gun.../+matthardigree

Interesting article on the planned F-14 Tomcat derivitives.

I started my career back in the mid 80's working on analog engine controls for GE aircraft engines. I remember when we started production of the F110-400 engine control for the Tomcat. We were given literature about the performance increase of the aircraft over the P+W TF-30. It looked impressive. Eventually the Air Force went with the F110-129 replacing the F110-100 in their F-16's. We always wondered how the Tomcat would perform with a pair of F110-129's.

 

[spasm3]

Loved the Tomcat. The Tomcat 21 would have been cool! Stealth might have been tough to accomplish, but the range and radar ability of an upgraded redesigned Tomcat would have been awesome!
Astro14 would know better but the titanium electron beam welded wing boxes limited the tomcat to i think it as 7.5 or so G's. I think the military limited it to 6.5 G's to prolong airframe life.

 

[Astro14]

The Tomcat's airframe was a remarkable structure...the titanium wing box was far stronger than the rest of the jet. Limiting the G to 6.5 did prolong airframe life, but it was things like fuselage longerons, shear webs (monocoque structure under the twin tails) and the AWG-9 antenna that began to fatigue at the higher G levels.

The Navy considered raising it to 7.5 G as a stress limit, but the tactical performance increase was modest and the fatigue life cost was high, so it was kept at 6.5G. The fatigue and engine monitoring system (FEMS) in the F-14 B/D variants showed that the loads imposed by full stabilator deflection without spoiler augmentation (wings positioned aft of 57 degrees disabled spoilers) twisted the fuselage and strained those areas I mentioned above.

I am here to tell you though, that at 8.5G in a hard pull, the airplane flies just fine, your RIO nearly blacks out, your skin tingles from broken capillaries and the pursuing F-16 overshoots your flight path...

However, after landing, your penance should include helping the jet engine shop re-install the engines because they both shifted in their mounts. It was a young pup's mistake, compounded by adrenaline and the transonic pitch-up as the airplane decelerated through mach 1...

We all got briefed on Quick Strike and Super Tomcat 21 back in the early 90s. It would have been nice to see the power, fuel capacity and weapon system capability increase in what was already a great airplane.

Still miss that jet...

 

[spasm3]

Thanks for the info!
Everyone of your posts about the tomcat makes me drool! I wanted to go navy after high school but with already corrected vision, flying a tomcat was never going to happen.

 

[Astro14]

I should add that a slick (no stores) F-14B would, in fact, supercruise...it would stay supersonic in mil power (no AB) for many hundreds of miles...flew a -B model from Key West to Oceana NAS in 55 minutes one night....

 

[expat]

Maybe

But are we close to having the last Piloted fighter?

ie. Is the human pilot the limiting factor in performance.

 

[OneEyeJack]

It's too bad the Tomcat did not get the GE engines from the start. Some of us here that worked on the chemical milling for the titanium ducts for GE at Chemtronics were really disappointed when they went with the PW engines. From a technical and practical point of view it made no sense at all.

 

[Astro14]

Originally Posted By: expat
Maybe

But are we close to having the last Piloted fighter?

ie. Is the human pilot the limiting factor in performance.


Maybe...

Let's distinguish performance, however. For things like G-tolerance and endurance, humans in the airplane limit performance. People can't fly in a fighter cockpit and be effective past about 8 hours (my personal experience in Desert Storm)...also, humans are limited to about 9 G...

However, no autonomous plane that we've built is capable of air to air engagements. So, a plane without a human pilot would be able to pull more G, but it wouldn't be able to use that extra G because it isn't capable of the mission.

So, for the missions of which autonomous airplanes are capable (like strike, interdiction, etc.) the extra G doesn't help in mission completion. You don't need to pull crazy G to go deliver ordnance.

You do need to pull high G to defeat SAMs, or engage in air to air combat. The autonomous airplane can't do either. To pull an orthogonal SAM defense, you have to visually acquire the SAM. Radar warning receivers aren't precise enough in determining direction of arrival of the signal (which is the guidance signal, not the SAM arrival direction anyway), so autonomous airplanes are not going to be capable of that sort of maneuver, they lack the proper sensor (Mark 1, MOD 0 eyeball). So, the extra G capability of a "drone" is superfluous...

For a mission that is complex, requiring detailed integration with boots on the ground, the situation requires the judgement of a human. That human can be in the loop either from a cockpit, or in the control room of an RPV (remote piloted vehicle, which is what the Predator truly is...it is NOT, and never has been, a "drone"). But those planes with remote pilots are not built to maneuver, and are sitting ducks in a hostile air to air threat environment. The Predator has very, very long endurance...but it's slow, can't maneuver and has been shot down with RPGs, and small arms fire...

We can build a plane that flies to a target and delivers a weapon. We can build that plane with long endurance and high G capability, but that plane can't think, and it can't see, which makes it incapable of some missions. For missions in a high threat environment, for missions like air to air combat, you still need the pilot in the plane.

The Navy's UCLASS is a great airplane. It adds incredible new capability that the no one (not even the USAF) has and it doesn't risk a human pilot, but it represents precisely what I am talking about: great range, endurance, stealth, but limited mission set: strike and surveillance. It's a drone (autonomous) and will fly a complex profile, but it can't do close air support, air superiority, and the missions that require on scene judgement...

http://en.wikipedia.org/wiki/Unmanned_Carrier-Launched_Airborne_Surveillance_and_Strike

 

[Astro14]

Originally Posted By: OneEyeJack
It's too bad the Tomcat did not get the GE engines from the start. Some of us here that worked on the chemical milling for the titanium ducts for GE at Chemtronics were really disappointed when they went with the PW engines. From a technical and practical point of view it made no sense at all.


It was a purely monetary decision in a post-Vietnam declining defense budget era...the airplane had flown with TF-30s (developed for the F-111) as demonstrator engines. Pratt was working on an advanced engine at the same time that GE was developing the F101 DFE (which would later become the F110). But budget was tight, and the TF-30 was paid for, and Navy decided to keep its air superiority airplane funded rather than risk its cancellation due to engine cost increase...

The first "Super Tomcat", the original F-14B was built in 1974 with a prototype of Pratt's new engines. The performance was eye-watering...but the DOD couldn't afford the cost...and it wasn't until 1986, when SECNAV John Lehman, looking at the number of F-14 airframes (and cerws) lost due to TF-30 failures, mandated that the airplane get better engines. The F-110-400 was engineered to fit in the F-14 airframe (longer AB section than the F-110-100 in the F-15 and F-16) and the F-14A+ was born. The name of that variant was later changed to F-14B to fit DOD standard nomenclature.

 

[tom slick]

Originally Posted By: OneEyeJack
It's too bad the Tomcat did not get the GE engines from the start. Some of us here that worked on the chemical milling for the titanium ducts for GE at Chemtronics were really disappointed when they went with the PW engines. From a technical and practical point of view it made no sense at all.


Off topic:

The fan ducts on the F101 and F110 are are awesome parts. Large, curved, rigid, lightweight and made of what appeared to be one piece of titanium. The first time anyone lifted them it was a surprise. They were also quite expensive.

 

[azsynthetic]

Originally Posted By: Astro14


However, no autonomous plane that we've built is capable of air to air engagements.


No one on earth has build an autonomous air to air combat vehicle yet. That is because there isn't a need for it, yet. There is a plan to build one though, but it is more of a Kamikaze drone.