RN Phantoms - extended nose gear

[NWSRG]

Folks,

Wondering if anyone can explain the the reason why Royal Navy Phantoms needed an extended nose gear leg, compared to their US counterparts. I'm guessing the increased angle of incidence did a lot for payload and takeoff speeds, but that leg must have been under immense load during takeoff.

Maybe some RN veterans would have more insight?

[Dr Jekyll]

I heard from an Ark Royal veteran that it was indeed to increase angle of incidence to cope with the relatively small flight deck.

[Terry McCassey]

Angle of attack I believe is more accurate as the angle of incidence is the fixed relationship between the wing and the chord line - I'll get my coat.

[NWSRG]

Angle of attack I believe is more accurate as the angle of incidence is the fixed relationship between the wing and the chord line - I'll get my coat.

I suspected I might have got that wrong...:ok:

Still reckon the nose gear leg looks mighty spindly...of course, I'm assuming the catapult acted on the nose gear...maybe not?

[NutherA2]

The F4 was launched by a bridle which was attached to the fuselage somewhere near the wing roots, not to the nosewheel. I stand to be corrected, but I believe all USN & RN Phantoms (F4B/N, J & K) had the extendable nosewheel oleo which was incorporated to give the aircraft an appropriate angle of attack during the catapult launch.

[NWSRG]

The F4 was launched by a bridle which was attached th the fuselage somewhere near the wing roots, not to the nosewheel. I stand to be corrected, but I believe all USN & RN Phantoms (F4B/N, J & K) had the extendable nosewheel oleo which was incorporated to give the aircraft an appropriate angle of attack during the catapult launch.

Thanks NutherA2,
That makes sense...if you check the Wikipedia page for the Phantom, there is a pic of both RN and USN Phantoms on the USS Independance, side by side, on exercise. The USN machine looks to have an extended nose gear leg, but not to the same extent as the RN one...the RN one looks about 6 or 8 feet tall!

[Kitbag]

It's also worth remembering that the UK machines were very different to the US ones due to the installation of the RR Spey



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[Terry McCassey]

The RAF F4M's had the launch hooks covered with a panel, just under the intakes on both sides. I was told that the strop during the launch was thrown forward and into the sea. £10 a time for the strop I believe in the early seventies !

[sidtheesexist]

Terry

Is not the angle of incidence the angle between the mean chord line and the longitudinal axis in straight and level condition? I.e the 'in built AoA'?

[Background Noise]

Angle of incidence is the angle that the wing is bolted to the fuselage.

Angle of attack is the angle between the wing and the relative airflow.

[CharlieOneSix]

I was told that the strop during the launch was thrown forward and into the sea. £10 a time for the strop I believe in the early seventies !

That used to be true up until the end of the fifth commission of Ark Royal (my time on board) which ended on 5 October 1966. During her subsequent refit which enabled her amongst other things to operate the Phantom, she had the Van Zelm bridle (strop) arresting gear fitted which resulted in the extensions forward of the flight deck which caught the strop.

Eagle did the Phantom trials in March 1969 but I don't know whether the bridle arresting gear was fitted at that time. Edit: found out that Eagle never had bridle catchers fitted so the bridles would have been ditched on each launch so Terry is correct that this occurred up until the early 70's - Eagle decommissioned for the last time in 1972.

The reason for the extended nosewheel leg was to avoid the necessity for the pilot to put in a large tailplane angle in order to rotate the aircraft as it left the bows. (quote by Cdr Hefford who flew the Phantom on deck trials - in 1969 CO C Squadron, Boscombe Down). The Spey engines were installed at a slight downward angle compared with the US engined Phantoms.

[CharlieOneSix]

Further quote from Cdr Hefford which may be of interest regarding the Phantom launch technique:

"We devised a stick restraining device for use during a catapult launch. The idea was to set a tailplane angle while holding the stick against a wire strap which was under tension and retracted into the instrument panel when not needed. The tension was such that, should the pilot need more aft stick, he could overcome the restraining device. We completed tests at RAE Bedford before embarking and established that very consistent safe launching were possible, whereas USN launches showed very large variations in the rate and angle of rotation off the catapult. We could not use the "hands free" launch which was designed into, and was so successful, in the Buccaneer, because the control system balance was such as to cause the stick to rotate aft during launch, but we felt this was the next best thing. The disadvantage was that it had to be unclipped during the climb."

[Dr Jekyll]

Was there any truth in the rumour McDonnell were also hoping to sell UK style Phantoms to the US navy for use on the smaller types of carriers?

[NutherA2]

Was there any truth in the rumour McDonnell were also hoping to sell UK style Phantoms to the US navy for use on the smaller types of carriers? Unlike the Phantom FGR2 (F4M), the FG1 (F4K) incorporated a fixed slat on the stabilator leading edge and aileron droop when flaps were deployed; this reduced the approach speed by some 13 knots, in recognition of the limitations of the arrester wires & flight deck size of Ark Royal (and Eagle). The USN F4J also had these features; might this have been the origin of the rumour?

[Terry McCassey]

Great stuff Charlie and thanks for sharing. I think in my so far nearly 42 years of aircraft maintenance, my time on the F4 was the most interesting. Because I enjoyed it so much, I seem to remember more about that type than all the machines I am current on these days. There are volumes of information about the F4 available and every time I dig, I learn something new . . . .

[DeepestSouth]

In about 1988, we installed a tie-down point at Honington in preparation for a 'Bolthole' for a Phantom squadron. It had to be tested, of course, and that was achieved by tying-down a Phantom, with the CO of the squadron in the cockpit IIRC, and running it at full chat, then with full reheat - to see if the tie-down held. It did. I noticed, though, that just before 'giving it welly', the pilot extended the nose leg - the gentle rising of the nose was quite elegant to watch. No idea why it was extended and as he taxied off afterwards, I never had the chance to ask.

I was standing a few feet from the stbd wing whilst all this happened. Even with ear defenders, a most impressive sound and much vibration through my DMS shoes. When self and PSA chaps wandered on to the concrete to check the tie-downs - it was still flippin' hot and started to melt the rubber on my shoes - so, quick scarper on to the grass!

[John Eacott]

I managed to get a few photos of the F4K, having done a couple of tours on Ark. These were from 1974 and show the sequence off the waist cat:

http://www.eacott.com.au/gallery/d/1670-1/Phantom+waist+cat+launch+Ark+Royal+1974+04.jpg

http://www.eacott.com.au/gallery/d/1672-1/Phantom+waist+cat+launch+Ark+Royal+1974+05.jpg

http://www.eacott.com.au/gallery/d/1674-1/Phantom+waist+cat+launch+Ark+Royal+1974+06.jpg
http://www.eacott.com.au/gallery/d/1676-1/Phantom+waist+cat+launch+Ark+Royal+1974+07.jpg

Re the extended NLG, I also recall that it was a fairly serious issue if the extended NLG failed to retract. Apart from being unable to retract there were issues (IIRC) that prohibited a landing, this photo was a low pass to visually inspect the NLG due to spurious cockpit indications;

http://www.eacott.com.au/gallery/d/1632-1/Phantom+012+low+pass+for+gear+inspection.jpg

The US F4 (a USMC version) shows their NLG, which obviously wasn't too much of an issue off our cats as we cross decked a lot. Which makes me wonder if the explanation by C16 is the full SP?

http://www.eacott.com.au/gallery/d/1696-1/US+Marine+Phantom+RN+colours+07+off+waist+cat.jpg

And a USN F4:

http://www.eacott.com.au/gallery/d/3267-2/USS+JFK+F4+on+waist+cat+Ark.jpg

An F4K for comparison from the same angle

http://www.eacott.com.au/gallery/d/1626-1/Phantom+005+dusk+launch+Ark+waist+cat.jpg

[blaireau]

From memory, the F4K extended by 40" on a double telescopic compared with the USN/USMC 20" extension.
On the K this gave 9 degrees of incidence and the rotation at the end of the cat stroke was a further 5 degrees minimum to achieve climb-out at launch speed dependent on launch weight.
But, it's all a long time ago.
Nice shots John.

[54Phan]

Lovely pictures, thank you.