F-14A & B System change

[ChockP51]

Lately, I went through some F-14A material from Grumman. Compare to a NATOPS F-14B& D available publicly, I went through and here I have some questions about the difference.

 

1. F-14A show a figure of bleed door schedule but in F-14B NATOPS mention that these bleed door always open. Is this a change related to engine-intake matching? and if we bleed door open is it possible to see it open from the outside ?

 

2. F-14A mention that there is a switch in the cockpit that allows a pilot to select wing sweep program schedule that maximizes Ps or CLMax. Is this switch persist in operation aircraft?

 

3. F-14A allows maneuver flaps to be extended up to sweep angle 50 degrees but our F-14B & NATOPS seems to allow extended maneuver flap only at the most forward sweep angle.

 

4. Will we have the power trim indicator gauge available in our F-14A?

[Quid]

I'm guessing you have the Preliminary Technical Order made by Grumman for the F-14A from 1 June 1972, because a lot of the stuff you're describing isn't found in later versions, and there were some significant changes even before the F-14's initial cruise two years later.

 

For question 1, if you're talking about the inlet bleed door on top of the intake nacelles, it was fixed in place at least by 1982, and likely earlier since no airframe change is listed in later manuals indicating a modification to the bleed door after the aircraft was IOC. The Preliminary T.O. from 1972 describes it as a "forward hinged, two-positioned bleed door with side plates" but by 1982, it is referred to as a "fixed bleed door" and the image showing its operation does not carry a change designation. It may have been fixed in place before 1974. The odds are, HB's F-14A isn't going to be a pre-production model, so I wouldn't expect these to move.

 

For question 2, the two-position "Sweep Prgm Switch" is not to be found by 1975. J.P. Stevenson's "Grumman F-14" by Tab Aero, first published in 1975 includes cockpit layouts which show how rapidly the aircraft's cockpit was changing by bureau number and airframe change. His source list includes the 1 November 1973 preliminary NATOPS manual (the likely source of what are usually foldouts, reformatted to fit his book), and the switch isn't included in any of the cockpit layouts, to include as an airframe change.

 

For question 3, that's a misreading for the later manuals. In the PTO, it states the main flaps may be extended between 0 and 10 degrees with a wingsweep angle of less than 50 degrees. At this time the F-14A didn't have automatically-programmed maneuver flaps; it was totally reliant on the thumbwheel. Later F-14A/B/Ds had automatically positioned maneuver flaps (F-14A Block 90/BuNo 159825 and beyond) which could be overridden by the pilot using the thumb wheel, and the main flaps (the same ones used for maneuver flaps) could be commanded at wing sweep angles of less than 50 degrees, the same as the number listed in the PTO. So, no change there, other than that the pilot's positioning of the maneuver flaps became secondary to the CADC.

 

For question 4, no idea.

[ChockP51]

I'm guessing you have the Preliminary Technical Order made by Grumman for the F-14A from 1 June 1972, because a lot of the stuff you're describing isn't found in later versions, and there were some significant changes even before the F-14's initial cruise two years later.

 

For question 1, if you're talking about the inlet bleed door on top of the intake nacelles, it was fixed in place at least by 1982, and likely earlier since no airframe change is listed in later manuals indicating a modification to the bleed door after the aircraft was IOC. The Preliminary T.O. from 1972 describes it as a "forward hinged, two-positioned bleed door with side plates" but by 1982, it is referred to as a "fixed bleed door" and the image showing its operation does not carry a change designation. It may have been fixed in place before 1974. The odds are, HB's F-14A isn't going to be a pre-production model, so I wouldn't expect these to move.

 

For question 2, the two-position "Sweep Prgm Switch" is not to be found by 1975. J.P. Stevenson's "Grumman F-14" by Tab Aero, first published in 1975 includes cockpit layouts which show how rapidly the aircraft's cockpit was changing by bureau number and airframe change. His source list includes the 1 November 1973 preliminary NATOPS manual (the likely source of what are usually foldouts, reformatted to fit his book), and the switch isn't included in any of the cockpit layouts, to include as an airframe change.

 

For question 3, that's a misreading for the later manuals. In the PTO, it states the main flaps may be extended between 0 and 10 degrees with a wingsweep angle of less than 50 degrees. At this time the F-14A didn't have automatically-programmed maneuver flaps; it was totally reliant on the thumbwheel. Later F-14A/B/Ds had automatically positioned maneuver flaps (F-14A Block 90/BuNo 159825 and beyond) which could be overridden by the pilot using the thumb wheel, and the main flaps (the same ones used for maneuver flaps) could be commanded at wing sweep angles of less than 50 degrees, the same as the number listed in the PTO. So, no change there, other than that the pilot's positioning of the maneuver flaps became secondary to the CADC.

 

For question 4, no idea.

 

Thank you sir for your detailed answer. Yeah I think we look are the same Preliminary technical Order and you pretty much clear most of my questions.

It’s a shame that some cool switch and feature didn’t make it to the operation plane such as autopilot mach hold function and wing sweep schedule program selector.

 

3. For F-14B NATOPS it doesn’t explicitly said that the maneuver flap can be manually extend with wings sweep less than 50 deg. In fact the figure 2-51 in F14B NATOPS show where maneuver flap can be extend. At SL F-14B maneuver flap will retract at around M0.6 which is about wing sweep angle of 21 degree. Granted, the PTO F14A has the maneuver flap schedule limit as well. However, the graph is with respect of dynamic pressure.

[Quid]

Thank you sir for your detailed answer. Yeah I think we look are the same Preliminary technical Order and you pretty much clear most of my questions.

It’s a shame that some cool switch and feature didn’t make it to the operation plane such as autopilot mach hold function and wing sweep schedule program selector.

 

3. For F-14B NATOPS it doesn’t explicitly said that the maneuver flap can be manually extend with wings sweep less than 50 deg. In fact the figure 2-51 in F14B NATOPS show where maneuver flap can be extend. At SL F-14B maneuver flap will retract at around M0.6 which is about wing sweep angle of 21 degree. Granted, the PTO F14A has the maneuver flap schedule limit as well. However, the graph is with respect of dynamic pressure.

 

Read the paragraph on Flap Wing Interlocks and you'll find the 50-degree limit. You should also see a "Wing-Sweep Interlocks" graph that shows the maximum wingsweep positions where the pilot may extend the main flaps (out to 50 degrees). Note also that the CADC can drop maneuver flaps based on AoA at airspeeds higher than those listed in the MF Envelope (figure is "Maneuver Slat/Flap Automatic Schedule for CADC"). By that chart, even if you're at SL at .7M, if you have around 10 units AoA on the jet, the CADC will lower the maneuver flaps.