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Hawker aircraft

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brunel
639184.  Sun Nov 22, 2009 7:18 am Reply with quote

Thank you very much for that Mike - it's interesting to see how quickly the aircraft of WW1 developed so quickly.

 
Sadurian Mike
639326.  Sun Nov 22, 2009 2:58 pm Reply with quote

No problem. Yes, WWI saw the expansion of aircraft from fragile "toys" to machines that were capable of carrying heavy loads long distances, or performing acrobatics that would have torn apart the aircraft of only four years earlier.

As for the armament, early aircraft were often not even routinely armed with machine-guns but that is not to say that offensive uses weren't envisaged. As masterfroggy points out, the French were experimenting with cannon in their aircraft as early as 1910 (although that one never flew), and by 1913 had successfully trialled a Voisin Model 13 armed with a 37mm cannon.

During WWI the French persisted in arming aircraft with cannon, despite them being slow to load and usually very inaccurate. They never developed an automatic cannon during the war, but were great pioneers of mounting heavy weapons in aircraft nonetheless.

 
PDR
639370.  Sun Nov 22, 2009 5:45 pm Reply with quote

Celebaelin wrote:
The Hunter had to have two strengthening pods fitted to the fusilage (the port one can be seen in the photograph above just below the cockpit) to compensate for the stresses placed on the airframe by firing the 30mm cannon which they were ultimately fitted with.


They aren't "strengthening" pods - they're just tanks which collect the cartridge links to prevent them battering the heck out of the airbrake and tailplane. I had cause to dig out the drawings and stress calcs a few years ago when a private owner wanted to convert one into a baggage carrier - they're not exactly "robust" pieces of structure!

PDR

 
PDR
639372.  Sun Nov 22, 2009 5:49 pm Reply with quote

As a peice of related trivia - the Kingston fatcory which Tommy Sopwith set up after establishing the new Hawker company in (I think) 1921 continued until it closed in 1992 (when we moved the design organisation to Farnborough and the manufacturing facilities mostly to Dunsfold). At the time it closed the Kingston plant held the world record of being the aircraft manufacturing site with the longest unbroken history of building its own designs (it never built anything but its own designs).

I think this record still stands.

PDR

 
Sadurian Mike
639395.  Sun Nov 22, 2009 8:38 pm Reply with quote

The Hawker Hurricane is one of the most famous British aircraft, arguably second only to the Spitfire with which it shared many plaudits.

The Hurricane was the result of Hawker deciding to produce a monoplane variant of its highly successful "Fury" aircraft, married to the new engine that had just become available, the famous Rolls Royce Merlin. Hawker Hurricanes were ready in time for eighteen RAF squadrons to be equipped with them by the start of the Second World War, and during the Battle of Britain Fighter Command had 32 Hurricane squadrons as opposed to 19 Spitfire squadrons.



Outclassed by the ME109, its main single-engined fighter opponent, the Hurricane squadrons concentrated on attacking bombers and the clumsier twin-engined ME110 heavy fighters. During the Battle of Britain the Hurricane pilots would earn two important honours, the only VC awarded to Fighter Command (Ft Lt James Nicolson) and the highest allied scoring ace during the battle (Czech Sergeant Josef Frantisek, with 17 victories).

Although not given as great a promience as the Spitfire, the Hurricane is often considered to be at least as important in winning the Battle of Britain.



The Hurricane later went on to be a successful ground attack aircraft with bombs, rockets or two 40mm underwing cannon, and a convoy protection aircraft, the "Hurricat", which was catapulted from the deck of a ship and then had to ditch in the sea after its mission. Less expensive in terms of loss were Sea Hurricanes which were normal aircraft converted to fly from aircraft carriers. Hurricanes were also used by many other countries, including Russia, France, Finland, Australia and India.



The Hurricane was reportedly easy to fly and could soak up considerable damage* and was easy to repair, mainly due to its construction of steel tubes covered with fabric, a carry-over from its inter-war Hawker Fury ancestor.


*"a sheer joy to fly .... a reliable trustworthy workhorse, which could take a lot of punishment and still get you home" - bbc people's war

http://en.wikipedia.org/wiki/Hawker_Hurricane
http://www.aviation-history.com/hawker/hurrcane.html
http://www.bbc.co.uk/ww2peopleswar/stories/61/a3293561.shtml

 
Sadurian Mike
639397.  Sun Nov 22, 2009 10:15 pm Reply with quote

One more QI, if rather macabre and unfortunate, fact about the Hawker Hurricane is that the first RAF pilot to be killed during WWII was Montague Hulton-Harrop, who was flying a Hurricane at the time. He was shot down and killed on 6th September 1939, three days into the war. His wingman, Frank Rose, was also shot down but survived. That is unfortunate enough.

The very unfortunate part of it is that the aircraft that shot them down was an RAF Spitfire flown by John Freeborn, who had been directed to destroy the Hurricanes by ground control who had mistaken them for enemy aircraft, there being some confusion over the two Hurricanes' identity thanks to them taking off seperately from the rest of their formation who had been scrambled in response to a (false) raid warning.

The Hurricane thus became the first aircraft ever to be shot down by a Spitfire.


http://www.northwealdairfieldhistory.org/content/battle-barking-creek
http://en.wikipedia.org/wiki/Battle_of_Barking_Creek

 
Celebaelin
639402.  Mon Nov 23, 2009 2:56 am Reply with quote

PDR wrote:
Celebaelin wrote:
The Hunter had to have two strengthening pods fitted to the fusilage (the port one can be seen in the photograph above just below the cockpit) to compensate for the stresses placed on the airframe by firing the 30mm cannon which they were ultimately fitted with.


They aren't "strengthening" pods - they're just tanks which collect the cartridge links to prevent them battering the heck out of the airbrake and tailplane. I had cause to dig out the drawings and stress calcs a few years ago when a private owner wanted to convert one into a baggage carrier - they're not exactly "robust" pieces of structure!

PDR

I shall be sure to inform my father of his error.

 
Celebaelin
639519.  Mon Nov 23, 2009 12:50 pm Reply with quote

Pater has decided to take an old acquaintance to task on this point; that said acquaintance was formerly a Hunter pilot is neither here nor there of course.

The story currently remains that the squadrons were only permitted to fire two of the four cannon simultaneously until the modifications had been conducted to 'strengthen the airframe'. Since the ADEN modules were uninstalled and replaced as a unit after use (Sq.L. Celeb Snr. had to build the installation which performed this operation) the suspicion is that the spent belts were contained within the module. This may be simply what knowledge was available at the time regarding the ADEN but word from those involved so far (ie my father) goes against the specs and blueprints you have seen(!?) Any chance they were still subject to Official Secrets as regards the ADEN - which if my reading of Wiki is correct is still in use essentially unchanged? Is a mystery developing about the 'empty' pods?

<E> Update; the question is doing the rounds - will get back with the consensus in due course.

 
PDR
639528.  Mon Nov 23, 2009 1:23 pm Reply with quote

The pods are part of the (quick-change) gun pack, which is not a stressed part of the airframe. I think I may have traced the possible scope for confusion though. On initial entry to service the aircraft were limited to firing two guns at a time because the recoil shock-stalled (aka "pop-surged") the engine. A mod was introduced which inserted an interrupter into the fuel feed to address this, and after the mod the aircraft was cleared to simultaneously fire all four cannon.

The Avon engine was rather sensitive in its early versions - very prone to surge and flame-out. In fact the first development engine would only run at full power - in desperation to make it run at part throttle and transition reliably for development flying they took four stages out of the HP compressor!

This was a MAJOR embarrassment to Rolls Royce, because the Avon's rival (the Armstrong-Siddeley Saphire, as used in the Hunter F2) was extremely steady and unpurturbable. Some years later RR and AS had an exchange of technologies in which AS gained some vital information on hot-end alloys in exchange for disclosing the "secret" of the Saphire's robustness. The answer annoyed RR intensely - it was simply that the Saphire's compressor stages ran at less than 50% efficiency. RR had done an immense amount of work getting the Avon's compressor efficiency up to over 90%, and that's what made it so sensitive to airflow disturbances. Quite why they did this is not clear, because compressor efficiency in a turbojet doesn't have much affect on overall thrust efficiency or specific fuel consumption. The story can be read in more detail in various sources, Ray Braybrook's book being a good example.

NALOPKT(&EFGAS)

PDR

 
Celebaelin
639529.  Mon Nov 23, 2009 1:40 pm Reply with quote

Best information states that the pods were to accommodate clips from the ammunition belt and cases were ejected clear of any possible interference with the underside of the aircraft or the engine air intake. Pretty much as you said PDR.

Just read your latest post - I'm told that all four cannon were not in fact fired simultaneously as a rule. There was only one instance in which that was done - a high altitude test to familiarise the pilot with the retardation effects on airspeed of doing so!

 
PDR
639597.  Mon Nov 23, 2009 4:41 pm Reply with quote

Celebaelin wrote:
Just read your latest post - I'm told that all four cannon were not in fact fired simultaneously as a rule. There was only one instance in which that was done - a high altitude test to familiarise the pilot with the retardation effects on airspeed of doing so!


Yes and no - it depends which user. When the RAF switched the Hunter from fighter to ground-attack role they changed the operational clearence to twin-cannon use for two reasons: Firstly the shear number of shells fired by four cannon was way too much for any ground target, and just wasted ammunition. Secondly the ground-attack runs were made at relatively low speeds (around 280-300kts) for easier target acquisition, and at these speed and low altitudes the recoil retardation from four cannon was seriously dangerous.

But the Swiss (who were one of the last to fly Hunters operationally, and only retired them a few years ago) generally used short bursts with all four, and the Fleet Air Arm (who used Hunters as weapons trainers for their Sea Harrier pilots) only trained air-air gunnery at medium altitudes, so they generally used all four as well. I do remember the gunfire vibration cases were the major issue in the final fatigue life-extension we did on the Swiss fleet, and I'm pretty sure the default case was a four-gun burst.

PDR

 
Alfred E Neuman
639726.  Tue Nov 24, 2009 3:52 am Reply with quote

Very interesting stuff here. Thanks guys.

 
PDR
639755.  Tue Nov 24, 2009 5:29 am Reply with quote

Having dug a little further into the design record last night (you've piqued my interest, so I'm going to bill you for a new set of eyes tp replace the ones that have been ruined by staring at pages of archive microfiche) I've found various structural mods to the forward fuselage, some of which look like they were to address gunfire-vibration induced cracking. But these were mid-life and late-life mods (100FI onwards) that were part of the normal structural integrity programme of an ageing aircraft. I haven't found any references to related limitations on gun firing - if there were any they'd be cited on the Form 715 for the mods in question (because the justification for the mods would be to remove the limitation).

PDR

 
Sadurian Mike
640029.  Tue Nov 24, 2009 5:43 pm Reply with quote

Here's some video of the Hunter in live firing training. The cannon are fired at a towed target drogue. At the end of the clip the Hunter attacks ground targets with (unguided) rockets and a couple of napalm bombs.

I had to turn off the sound as the music was getting on my nerves, there is no "natural" sound to the clip.

http://www.youtube.com/watch?v=zVPr6UpqgkU

 
Celebaelin
640135.  Tue Nov 24, 2009 11:21 pm Reply with quote

Going off-topic briefly I've just watched this and I think everybody reading the thread will enjoy it.

American documentary on the Typhoon (ie Eurofighter)

 

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