F4 question
 

Yes, we were taught to use full aft control column for take-off, releasing the back pressure slightly and as required when the aircraft was about to become airborne.

Yes, this was SOP on all RAF variants i.e FG1, FGR2 and F4J. I regret that, 30 years later, I cannot recall why but I assume that it was due to aerodynamics plus ensuring best use of runway.. Someone out there will have the answer.

On heavy for jet aeroplanes that tend to use an awful lot of runway the procedure was changed in the 1950's. Holding the stick back and accelerating with the elevators up would increase the drag once they get some effect but not enough to lift the nose. Lifting the nose wheel and waiting for the aircraft to lift off also slows the acceleration.

The technique arrived at was to let the controls stream until about 25 knots before the calculated unstick and then rotate the aircraft so that it unsticks at the desired speed.

far more gentlemanly; or should I say personably.

Did not the Fleet Air Arm use a piece of calibrated string attached to the control column to prevent too much forward movement of the column after a catapult launch?

I don't know the reason for this technique in the F-4 but I have what seems to be a plausible explanation. With a tricycle undercarriage aircraft, when initially rotating on the ground the point of rotation is the mainwheels. As the aircraft unsticks, the point of rotation in pitch becomes the centre of gravity which is forward of the mainwheels. Therefore, the horizontal stabilizer instantly has a longer moment arm resulting in an instantaneously larger nose up pitching moment for a given stabilizer angle. This could result in an unpredictable response in pitch. However, using the F-4 technique, as the nosewheel starts to lift off the runway the pilot is given a cue to smoothly move the stick forward which results in a smooth capture of the desired pitch attitude after unstick. I suspect that it is just that the pitch response characteristics of the F-4 in this flight regime make this a good technique. Also, it is simple and calculation of a rotate speed is not required.

However, there is the potential for the horizontal stabilizer to scrape the runway during rotation. On one of my very early sorties in the F-4 I was flying a totally clean F-4K which thereby had a very aft c.g position. It rotated more rapidly than I had seen on my previous sorties and although I moved the stick forward more quickly the stabilizer tips still scraped the runway. Luckily, the rubbing strips worked and there was no damage. I was not the first to do this so we refitted a ballast Sparrow on the front station!

Full aft stick take-off rolls are also flown on Hunter post-maintenance test flights to check the nosewheel lift-off speed although the pitch attitude is then checked and a normal unstick speed used.

I believe that this was to stop aft movement of the stick top due its inertia during the acceleration of the catapult launch.

I'll buy that

Beardy,

It was called a stick positioning device and consisted of a small drum of cable, the end of which could be clipped to the forward side of the stick top. As Lomcevak said, its purpose was to prevent inadvertant aft movement of the stick during catapult launch. The drum had a clutch which could be overridden by pulling harder if necessary to raise the nose in an emergency. During my apprenticeship at Hawker Siddeley Aviation Brough in 1970, I worked in Structural Test and carried out the endurance test on the device which consisted of operating it several thousand times by hand and checking the breakout load of the clutch at regular intervals. Not the most exciting way of pushing forward the frontiers of aviation.

Walbut

On 228 we taught using full aft stick till 10 deg nu and then holding till lift off. This ensured formation take-offs were together. One of the instructors queried this technique, but full aft stick produced an earlier lift off than rotating at lift off speed. No special skill was required for this technique as all members of a formation did the same thing!

On the F-4, all versions, the nose gear was heavy loaded. (Just look at any landing, even with a light aircraft, once the mains touch? The nose drops like a rock even when the chute is pulled early)

To reduce wear and tear on the nose wheel and strut it was advised to lighten the nose ASAP during a full fuel take off and even more so with stores.

Interesting to hear all this analysis . Back in the day , you didn't think too much about things , you just did as you were told , and it generally worked ok . What's that old saying about too much knowledge being a dangerous thing ? Favourite Chick Childerhose quote re guage markings--" green means go ; that's all any fighter pilot should be expected to remember " .

Mind you , in the F4 , it was always a good idea to pay close attention when the instructor told you " when it buffets , use your boots"....

From a USAF F-4E manual stilton.

NORMAL TAKEOFF - The slats out-flaps down position is recommended for all takeoffs. After taking the runway and completing necessary pre—takeoff checks, engines can be run to 85% with brakes held and nose gear steering engaged to ensure nose gear alignment. With both engines operating in excess of 85% and the brakes locked. there is a possibility of rotating the tires on the wheel rims or skidding the tires. Check for normal rpm response and approximate readings of 450‘C EGT, 4000 pph fuel flow, one quarter nozzles, and 30-40 psi oil pressure. After releasing brakes, advance both throttles rapidly to full military power and check rpm, exhaust temperatures and nozzle position. WSO check the ramps fully retracted. If an afterburner takeoff is desired, shift the throttles into the afterbumer detent and advance full forward for max thrust. Maintain directional control with nose gear steering or rudder as required. The rudder becomes effective for steering at approximately 70 knots. Wheel braking should not be used for directional control during takeoff roll. Nose gear steering should he disengaged when rudder steering becomes effective. If it becomes necessary to re-engage nose gear steering at the higher speeds, rudder pedals should be returned to neutral prior to engagement since rudder displacement necessary for rudder steering will generally be excessive for nose gear steering. Sufficient aft stick should be applied prior to nose wheel lift off speed to attain the desired pitch attitude. As the nose rises, pitch attitude must be controlled to maintqain a 10° to 12° (first pitch mark) nose high attitude for aircraft fly-off. Caution must be exercised to preclude over-rotation due to excessive aft stick or an extended take off due to late lift off. The basic take off attitude should be held during acceleration and transition to a clean configuration. Trim change and control action during this period are normal. The AUX AIR DOORS. WHEELS, and MlASTER CAUTION lights may illuminate momentarily as the landing gear and flaps are retracted.

CAUTION - Rapid full aft movement of the stick between takeoff airspeed and 30 knots below takeoff airspeed may result in the stabilator hitting the runway with the possibility of stabilator actuator damage.

NO-FLAP TAKEOFF - No-flap takeoffs are not recommended. However. if it is determined that no-flap takeoffs must be performed to satisfy mission requirements. aircrews should be aware that takeoff roll and airspeed will be increased and the takeofl attitude will be slightly steeper. Stabilator effectivetress is considerably increased and extreme caution must be exercised to prevent overrotation which could result in the stabilator striking the runway.

WARNING - Due to increased stabilator authority with the flaps up, aircraft rotation can be initiated at lower than normal airspeed: and overrotation is a definite possibility. If it appesrs that overrotation is occurring, positive oontrol rnovernent (stick forward) rnust be taken to prevent the stabilator from contacting the runway and/or loss of control.

MINIMUM RUN/IHEAVY GROSS WEIGHT TAKEOFF - A minimum run/heavy gross weight takeoff (aircraft over 55,500 pounds) is accomplished in the same manner as a normal takeoff with the following exceptions. It is
recomended that all minimum run/heavy gross weight takeoffs he rnade with aterburner. During the talreoff run. full aft stick must he applied prior tn reaching 80 knots. As theaircratt starts to rotate.thestick should be adjusted to maintain 10° to 12° pitch attitude for aircraft fly-off. The possibility of a main landing gear tire failure increases with an extended takeoff‘ ground run under heavy gross weight conditions. Nose wheel liftoff speed and takeoff speed is increased during heavy gross weight conditions. In the event of an aborted takeoif, it must be remembered that stopping distance is greatly increased as abort speed increases.

CAUTION - With a combination of light gross weight and aft CG, the minimum run takeoff technique (i.e., full aft stick prior to reaching 80 knots) produces rapid pitch rates during nose rotation. This combination can exist when the radar package and nose gun (or equivalent ballast) are not installed.The manual uses a decision speed, same as civil V1. Failure prior to, abort, after continue. If the take off is on military power checklist says to go to full afterburner on the good engine, so rudder authority wouldn't seem to be an issue.

Salute!

Don't think many of the RAF folks who contribute so much here, but maybe some RCAF F-5E drivers could help.

Seems to me that the F-5E gear configuration and cee gee was such that they needed to crank up the nose for takeoff. Apparently the elevatror didn't have enough control authority to change pitch at a reasonable speed racing down the runway. I lurched one day behind our "agressor" folks and they had some gizmo that actually extended the nose gear to raise the nose.

I only flew the F-18 sim once at St Louis, but apparently the rudders were canted in for takeoff to help get a nose up pitch moment.

Gums wonders....

With the low set anhedral stabilator, if you held a constant stick position all the way to touchdown the aircraft would pitch slightly nose down due to the stab entering ground effect before the wings. Apparently, this did not occur when landing on a carrier deck because you didn't get the same ground effect. Personally, unless on a runway length limited landing, I would apply slight aft stick just before touchdown in order to maintain a constant pitch attitude and AOA.

Different F4 marks/models had different brakes so the braking issues did vary. The F-4M/FGR2 certainly had the 'good' brakes.

One other interesting aspect of the F4 was that in a crosswind you did not kick off drift because the aileron-rudder interconnect would generate excessive roll if you did; you touched down with the 'crab' applied.

F4 Takeoff technique was standard on most models. The aircraft sat on the ground with the wing at a low incidence. 3/4 to full aft stick was used to rotate the wing to the optimum angle. As the speed increased through 100kts it was required to ease the stick forward to capture about 12deg pitch angle. The aircraft would fly off between 145 and 205 kts dependant on configuration, temperature and altitude. It was possible to "pull" the aircraft airborne early, however, not recommended.

Three main components affected the takeoff speed and distance; technique, C of G and nose strut extension. Any one of those out could extend the takeoff by 20%!! A USAF article written in the Phantom Digest in about 1970 called "Late Rotators" explain it very well.

As for approach and landing the F4 was a beast apart from other aircraft. Due to it's unique handling characteristics the aircraft had to be flown using AOA as the main reference. Apart from the AOA gauge the pilot was provided with Head Up Indexers and on some models Audio AOA. Once mastered to was possible to fly a stable approach very accurately to a precision touchdown. All naval variants (B,J,K,M,N,S) had strengthened landing gear, smaller wheels and were designed to land with No Flare. The USAF originated models (C,D,E,F,G) had different landing gear and wheels and required a flare to reduce the descent rate prior to touchdown. The UFAF IPs did not appreciate my naval landing technique.

As LOMCEVAK stated, Kicking off drift was a NO-NO.

Landed using the wrong techniques it was possible to use over 10,000 ft of runway to stop. As Audax stated, on 64(R) Sqn we perfected the short landing technique prior the the Falklands deployment and managed to stop in 2500 ft without using a cable. The brakes,however, would be very hot. Chute deployment should occur so that full deployment occurred at touchdown and not before. A 200ft deployment would be a little early in my opinion.

F I belts and braces
 

FI
https://cimg4.ibsrv.net/gimg/pprune....891130fcbf.jpg
belts and braces

Anyone recall the two A1 QFIs flying a 21AOA approach at Akronelli and landing in the undershoot? Tsk, tsk.....

Salute!

Some really great stuff on the last few posts
.
I flew three birds with an AoA gauge or indexer or bracket in the HUD.

The VooDoo did not emphasize use of the AoA gauge for landing or best cruise/holding. It was mainly an indication of how close you were to the pitch-up.

The A-7D and F-16A had an AoA bracket in the HUD for approaches and it was very useful as Lom has explained. The A-7D, being a USN derivative, but with vastly more advanced avionics, retained the USN "indexer" chevrons on each side of the HUD to show best approach AoA. Because stall and best approach speed changed a lot due to external ordnance and configuration, AoA was the best indication versus rules of thumb that related all the factors to a best approach speed. So if the guess was within 5 or 10 knots when the AoA indexers showed where to fly, then it was easy to transition and fly the AoA. The A-7D and F-16 had the AoA bracket in the HUD, so pulling or pushing that thing wrt the flight path marker made approaches a piece of cake.

I adopted the USN practice of flying the A-7D down to the runway with little or no flare. The F-16 required a bit of flare if you were hot or you would bounce. And as LOM has stated, no cross control for crosswinds!! Land the thing in a skid with the aileron interconnect feature would bite you in the butt when weight on wheels happened and the feature kicked out. F-16 was really touchy about that, but gear was close together and it was no biggie right after touch when landing wings level in a crab.

Gums sends...

Another part of landing the F4 that made it different was Boundary Layer Control (BLC), In either 7th or 12th stage BLC lift was being enhanced by air bled from the engines. If the throttles were retarded to idle too early the aircraft dropped like a stone. Better to fly the aircraft onto the ground.

Since the USAF operated off very long runways the BLC was inhibited. Then the jets E/S onwards got slats and that changed the aircraft's handling in the landing phase. Far more difficult to land in a very strong Xwind. I was happy to land a FGR2 with 35kts across whereas an E model with 25kts across was a handful!!

In any type you actually want to approach at a given AOA but most aircraft do not have AOA gauges so you fly an airspeed to achieve it. Flying AOA keeps it simple; the number is always the same whereas you have to adjust the airspeed for weight. In addition, a swept wing aircraft such as the F4 typically approaches below minimum drag speed, on the backside of the drag curve. The technique required to fly an accurate approach is to control AOA with the stick and rate of descent/approach path with power. Hence, you need an AOA gauge and you fly an AOA value and achieve an accurate approach.

The F-4K/FG1 had audio AOA but the F-4M/FGR2 did not. The tones used were identical to those on the Buccaneer. BUT, they worked in the opposite sense! When at the correct datum AOA for the approach in both types, you had a 'steady note'. But, when the AOA was less than this you had 'beeps' in the Buccaneer and 'burps' in the F-4 and vice versa when greater than the datum AOA. Not many pilots were current on both at the same time but I was for a while. I had a Buccaneer background so when flying the FG1 I used the gauge until 'on speed' then maintained the AOA using the on-speed tone.

The F-4M was not a naval version. However, the YF-4M (XT852) that was still flying through to at least 1990 did have the drooped ailerons and slatted stabilator as per the F-4K/FG1.

Sometime in the 1980's I attended a meeting at Boscombe Down to discuss heavy weight and single engined landing limitations for the UK Phantoms. Don Headley represented the BAE test pilots and I guess there were Flight test and Aerodynamics reps from BAe as well, but I can't remember who they were. My only reason for being chosen to attend was because, at the time, I understood the flight systems and the workings of the flap and BLC system and the associated 7th/12th stage bleed. It was intended to try and test various combinations of settings to allow approaches to be flown, potentially I think, even in reheat. I remember expressing some concern about some of the tests being proposed and Don Headley put me firmly back in my Flight Systems box. He pointed out that my concerns were based on the behaviour of the Buccaneer which could really bite if you reduced blowing pressures too far and in practice, the Phantom was much more benign. The main reason for the difference was that Phantom primarily 'blew' the leading edge of the wing and if blowing pressures were reduced, and the slits became unchoked, the aircraft would pitch nose down. Buccaneer on the other hand primarily blew the trailing edge of the wing and if BLC pressures fell too low, the aircraft pitched nose up which was the last thing you needed when low and slow and close to the ground. At the time the prospects of hot weather trials for UK Phantoms were pretty slim and Don probably did not want me to prejudice the chances of going on an interesting, if high risk, flight trial in an exotic location. I cant remember if or where the trials ever took place but in the back of my mind, I think it might have been Akrotiri

One minor deviation from this thread was that it fascinated me what you could hear on a Phantom engine run. I can remember the Rolls Royce rep pointing out to me when the engine changed from 7th to 12th stage bleed and vice versa you could hear it quite clearly among all the other racket from the engines when stood alongside wearing ear defenders.

Walbut

Not quite, only the F-4B, F-4N and all but the last 12 RF-4Bs had the narrow wheel/tyres, the F-4J, F-4K, F-4S and last 12 RF-4Bs had the wider wheels/tyres first seen on the USAF's F-4C...

-RP

I agree with Don that the Phantom was less affected by low blow pressures than the Buccaneer, but the Bucc had much more extensive BLC. The slits were all along the top of the leading edge of the wings, along the front edge of the mainplane flaps and under the leading edge of the tailplane. Even at minimum blow pressure and at datum speed the stabilised rate of descent was very high. Unblown approaches (45-10-10) were 19 KIAS faster than blown approaches with 45-25-25.

LOM .
All that I meant was that the K and M were both based on the J. Most of the RAF interaction with the aircraft, radar and weapons (AIM7 and AIM9) was with the USN.

As for Indexers and Audio AOA, there were various variations and combinations throughout the Family of F4s in different nations and forces.
Even such things such as Slotted Stabilator (F4F) were adopted in later variants.