Question for Astro14

[53' Stude]

Good afternoon again BITOGERS. Thank You to all service members by the way

Does anyone here know what was different about the Super Tomcat F-14. I know Astro 14 probably knows but there are probably people here that worked on the Tomcat or know. Thank You all in advance

 

[IndyFan]

I thought the primary difference was the addition of GE F110 engines to replace the Pratt TF 30. It may have also had an upgraded radar, too. I'm not sure about that, though. Those engines made it an entirely different airplane. Pilots said with the TF30, you had to fly the engine. With the F110, you could fly the airplane.

 

[53' Stude]

Thanks for the info sir

 

[javacontour]

IIRC, there was a recent thread about some F-14 crash footage. I believe Astro14 commented on the topic there, or at least regarding the engine issues.

 

[spasm3]

Here is the thread.

https://bobistheoilguy.com/forums/u...-questions-answered-ask-away#Post2911273

 

[Astro14]

The F-14 Tomcat was designed in 1968 with a 25,000# (or greater). thrust engine in mind. To get the first models flying, the TF-30, an existing engine of 20,000# of thrust was used. Interim engines were not uncommon in aviation history.

The original Super Tomcat was the F-14 that flew in about 1973 with Pratt & Whitney prototype engines that gave it a 30% increase in power over the TF-30.

This test program was successful, but cost over runs, inflation, and the end of the Vietnam War killed any money for the new engines in that airplane. The old TF-30s were "good enough" for Congress. The F-14A soldiered on with those engines.

In about 1980, that test article airplane was pulled back out, given new prototype GE engines (DFE - derivative fighter engine that would later become the F-110) and flew again. Successfully, but without a chance to go into production.

In 1986, Secretary of the Navy John Lehman directed the Navy, and lobbied Congress, to go ahead with new engines. The Navy had lost dozens of F-14s to engine failures and the cost of better, more reliable, higher power engines was cheaper than losing airplanes.

The F-110-400 GE engine was chosen, and the model was called the F-14A+.

It was renamed F-14B in 1991, to keep with Joint nomenclature and make the Navy's airplane model numbers compatible with USAF planning systems (CTAPS, at the time).

The F-14D model used this same engine, but had all new avionics with a digital data bus architecture and new mission computers, along with better ECM gear and an IRST (infrared search and track).

The term "Super Tomcat" has been applied to the prototype from 1973, and the A+, B and D models.

 

[53' Stude]

Astro, thank you for the great info sir

 

[A_Harman]

Wasn't the F-14 the first airplane to have more thrust than weight, and was able to accelerate in a vertical climb?

 

[Astro14]

Pretty sure that the F-15 owns that honor. Great airplane, the F-15.

Later versions of the F-14, with the GE F110-400 engines could accelerate while going straight up, but the Eagle could do that from day one, if my understanding is correct...

 

[4WD]

I watched a military video many years ago and it pointed out the F15 could pull off vertical acceleration …

Also worked with a former WSO (wizzo) who confirmed that …

 

[A_Harman]

Originally Posted by Astro14
Pretty sure that the F-15 owns that honor. Great airplane, the F-15.

Later versions of the F-14, with the GE F110-400 engines could accelerate while going straight up, but the Eagle could do that from day one, if my understanding is correct...


Ok, I remember that now! That is one massively powerful piece of hardware.

 

[john_pifer]

Does the F-15 have to do a zoom climb in order to accelerate vertically? How long can it sustain this vertical acceleration? I'm assuming it can't accelerate straight up right after takeoff (well, maybe for a couple thousand feet?).

 

[Astro14]

As with all things....it depends...

The colder the air, the more power the engines make (simple mass transfer, and the denser the air, the more mass is transferred per second). Increasing speed increases thrust in some airplanes (F-14 and F-15 among them) again, due to mass transfer. Higher speed = more air rammed into the engines by intakes designed to do just that.

Thrust/weight ratio depends both on thrust, and, of course, weight. Load the airplane lightly, and your ration improves.

The Streak Eagle - lightened as much as it could be, to the point of foregoing paint, with no weapons or extraneous external racks, and with only the fuel needed to set the climb record, took off from Saint Louis on a cold, cold day and set some incredible records for time to climb.

At roughly 450 KIAS, the F-14's intakes boosted engine thrust by about 30% over static levels. So, take an F-14B, with 23,800# per engine, and run it up to 450 KIAS, and you've got 32,000# of thrust, per engine. #64,000 of thrust in an airplane that weighs #42,000 empty. Depending on fuel load, it will accelerate while purely vertical. It's an awesome thing - to see 90 degrees of pitch, and see the airspeed increasing at the same time.

But the air gets thinner with altitude, and so the airplane loses thrust as it climbs. At about 25,000 feet, in the F14B, the airspeed begins to decrease, slowly at first, but then more rapidly as the air gets thinner.

Google the YouTube video for the Streak Eagle. It's an unbelievable performer.