Wednesday, 30 April 2014

The Junkers Ju 87 Stuka. Part 2: Development

The Junkers Ju 87 Stuka Part 2


Origins: Early design
The Ju 87's designer, Hermann Pohlmann, held the opinion that dive-bomber design needed to be simple and robust. This led to many technical innovations, such as the retractable undercarriage being discarded in favour of one of the Stuka's distinctive features, its fixed and "spatted" undercarriage.

 Pohlmann continued to carry on developing and adding to his ideas and those of Karl Plauth (Plauth was killed in a flying accident in November 1927), and produced the Ju A 48 which underwent testing on 29 September 1928. The military version of the Ju A 48 was designated the Ju K 47.

Ernst Udet; the greatest proponent of the dive-bomber and the Ju 87 (Photo 1928)

After Hitler came to power, the design was given priority. Despite initial competition from the Henschel Hs 123, the Reichsluftfahrtministerium (RLM) - Aviation Ministry - turned to the designs of  Pohlmann  and Plauth. During the trials with the K 47 in 1932, the double vertical stabilisers were introduced to give the rear gunner a better field of fire. The main, and what was to become the distinctive, feature of the Ju 87 was its double-spar inverted gull wings. After Plauth's death, Pohlmann continued the development of the Junkers dive bomber. The Ju A 48 registration D-ITOR, was originally fitted with a BMW 132 engine, producing some 450 kW (600 hp). The machine was also fitted with dive brakes for dive testing. The aircraft was given a good evaluation and "exhibited very good flying characteristics"

Ernst Udet took an immediate liking to the concept of dive-bombing after flying the Curtiss Hawk II. 
He invited  Luftwaffe OC Walther Wever and Robert Ritter von Greim to him  perform a trial flight in May 1934 at the Jüterbog artillery range, but it raised doubts about the capability of the dive bomber. Udet began his dive at 1,000 m (3,300 ft) and released his 1 kg (2.2 lb) bombs at 100 m (330 ft), barely recovering and pulling out of the dive. Wever, and the Secretary of State for Aviation, Erhard Milch, feared that such high-level nerves and skill could not be expected of "average pilots" in the Luftwaffe. Nevertheless, development continued at Junkers. Udet's "growing love affair" with the dive bomber pushed it to the forefront of German aviation development. He even went so far as to advocate that all medium bombers have dive-bombing capabilities.

Ju 87 evolution

The design of the Ju 87 had begun in 1933 as part of the Sturzbomber-Programm. The Ju 87 was to be powered by the British Rolls-Royce Kestrel engine. Ten engines were ordered by Junkers in 19 April 1934 The first Ju 87 prototype was built by AB Flygindustri (sv) in Sweden and secretly brought to Germany in late 1934. It was to have been completed in April 1935, but, due to inadequate strength of the airframe, construction was not completed until October 1935. However, the mostly complete Ju 87 V1 W.Nr.c 4921 (less non-essential parts) took off for its maiden flight on 17 September 1935. The aircraft originally did not carry any registration, but later was given the registration D-UBYR. The flight report, by Hauptmann Willy Neuenhofen, stated the only problem was with the small radiator, which caused the power plant to overheat.

The Ju 87 V1, powered by a Rolls-Royce Kestrel V12 cylinder liquid-cooled engine, and with a twin-tail, crashed on 24 January 1936 at Kleutsch near Dresden, killing Junkers' chief test pilot, Neuenhofen, and his engineer, Kreft. The square twin fins and rudders proved too weak; they collapsed and the aircraft crashed after it entered an inverted spin during the testing of the terminal dynamic pressure in a dive.The crash prompted a change to a single vertical stabiliser tail design. To withstand strong forces during a dive, heavy plating was fitted, along with brackets riveted to the frame and longeron, to the fuselage. Other early additions included the installation of hydraulic dive brakes that were fitted under the leading edge and could rotate 90°.

The RLM was still not interested in the Ju 87 and was not impressed that it relied on a British engine. In late 1935, Junkers suggested fitting a DB 600 in-line engine, with the final variant to be equipped with the Jumo 210. This was accepted by the RLM as an interim solution. The reworking of the design began on 1 January 1936. The test flight could not be carried out for over two months due to a lack of adequate aircraft. The 24 January crash had already destroyed one machine.

The second prototype was also beset by design problems. It had its twin stabilizers removed and a single tail fin installed due to fears over stability. Due to a shortage of power plants, instead of a DB 600, a BMW "Hornet" engine was fitted. All these delays set back testing until 25 February 1936.[12] By March 1936, the second prototype, the V2, was finally fitted with the Jumo 210Aa power plant, which a year later was replaced by a Jumo 210 G (W.Nr. 19310). Although the testing went well, and the pilot, Flight Captain Hesselbach, praised its performance, Wolfram von Richthofen told the Junkers representative and Construction Office chief engineer Ernst Zindel that the Ju 87 stood little chance of becoming the Luftwaffe's main dive bomber, as it was underpowered in his opinion. On 9 June 1936, the RLM ordered cessation of development in favour of the Heinkel He 118, a rival design. Udet cancelled the order the next day, and development continued.

Heinkel's He 118, the main competitor to the Stuka

On 27 July 1936, Udet crashed the He 118 prototype, He 118 V1 D-UKYM. That same day, Charles Lindbergh was visiting Ernst Heinkel, so Heinkel could only communicate with Udet by telephone. According to this version of the story, Heinkel warned Udet about the propeller's fragility. Udet failed to consider this, so in a dive, the engine oversped and the propeller broke away. Immediately after this incident, Udet announced the Stuka the winner of the development contest.

Honing the design

Despite being chosen, the design was still lacking and drew frequent criticism from Wolfram von Richthofen. Testing of the V4 prototype (A Ju 87 A-0) in early 1937 revealed several problems. The Ju 87 could take off in just 250 m (820 ft) and climb to 1,875 m (6,152 ft) in just eight minutes with a 250 kg (550 lb) bomb load, and its cruising speed was 250 km/h (160 mph). However, Richthofen pushed for a more powerful engine. According to the test pilots, the Heinkel He 50 had a better acceleration rate, and could climb away from the target area much more quickly, avoiding enemy ground and air defences. Richthofen stated that any maximum speed below 350 km/h (220 mph) was unacceptable for those reasons. Pilots also complained that navigation and power plant instruments were mixed together, and were not easy to read, especially in combat. Despite this, pilots praised the aircraft's handling qualities and strong air-frame.

These problems were to be resolved by installing the Daimler-Benz DB 600 engine, but delays in development forced the installation of the Jumo 210 Da in-line engine. Flight testing began on 14 August 1936. Subsequent testing and progress fell short of Richthofen's hopes, although the machine's speed was increased to 280 km/h (170 mph) at ground level and 290 km/h (180 mph) at 1,250 m (4,100 ft), while maintaining its good handling ability.

The Ju 87 was a single-engined all-metal cantilever monoplane. It had a fixed undercarriage and could carry a two person crew. The main construction material was duralumin, and the external coverings were made of Duralumin sheeting. Parts that were required to be of strong construction, such as the wing flaps, were made of Pantal and its components made of Elektron. Bolts and parts that were required to take heavy stress were made of steel.

The Ju 87 was fitted with detachable hatches and removable coverings to aid and ease maintenance and overhaul. The designers avoided welding parts wherever possible, preferring moulded and cast parts instead. Large airframe segments were interchangeable as a complete unit, which increased speed of repair.

The airframe was also subdivided into sections to allow transport by road or rail. The wings were of standard Junkers double-wing construction. This gave the Ju 87 considerable advantage on take-off; even at a shallow angle, large lift forces were created through the aerofoil, reducing take-off and landing runs.

In accordance with the Aircraft Certification Center for "Stress Group 5", the Ju 87 had reached the acceptable structural strength requirements for a dive bomber. It was able to withstand diving speeds of 600 km/h (370 mph) and a maximum level speed of 340 km/h (210 mph) near ground level, and a flying weight of 4,300 kg (9,500 lb). Performance in the diving attack was enhanced by the introduction of dive brakes under each wing, which allowed the Ju 87 to maintain a constant speed and allow the pilot to steady his aim. It also prevented the crew from suffering extreme g forces and high acceleration during "pull-out" from the dive.

The fuselage had an oval cross-section and housed a water-cooled inverted-V V-12 engine. The cockpit was protected from the engine by a firewall ahead of the wing center section where the fuel tanks were located. At the rear of the cockpit, the bulkhead was covered by a canvas cover which could be breached by the crew in an emergency, enabling them to escape into the main fuselage. The canopy was split into two sections and joined by a strong welded steel frame. The canopy itself was made of Plexiglas and each compartment had its own "sliding hood" for the two crew members.

The engine was mounted on two main support frames that were supported by two tubular struts. The frame structure was triangulated and emanated from the fuselage. The main frames were bolted onto the power plant in its top quarter. In turn, the frames were attached to the firewall by universal joints. The firewall itself was constructed from asbestos mesh with dural sheets on both sides. All conduits passing through had to be arranged so that no harmful gases could penetrate the cockpit.

The fuel system comprised two fuel tanks between the main (forward) and rear spars of the (inner) an-hedral wing section of the port and starboard wings, each with 240 L  The tanks also had a predetermined limit which, if passed, would warn the pilot via a red warning light in the cockpit. The fuel was injected via a pump from the tanks to the power plant. Should this shut down, it could be pumped manually using a hand-pump on the fuel cock armature.

The power plant was cooled by a 10 L (3 US gal) ring-shaped aluminium water container situated between the propeller and engine. A further container of 20 L (5 US gal) was positioned under the engine. The control surfaces operated in much the same way as other aircraft, with the exception of the innovative automatic pull-out system. Releasing the bomb initiated the pull-out, or automatic recovery and climb, upon the deflection of the dive brakes. The pilot could override the system by exerting significant force on the control column and taking manual control.

The wing was the most unusual feature. It consisted of a single center section and two outer sections installed using four universal joints. The center section had a large negative dihedral (anhedral) and the outer surfaces a positive dihedral. This created the inverted gull, or "cranked", wing pattern along the Ju 87's leading edge. The shape of the wing improved the pilot's ground visibility and also allowed a shorter undercarriage height. The center section protruded by only 3 m (9 ft 10 in) on either side.

Posted Image

The offensive armament was two 7.92 mm (.312 in) MG 17 machine guns fitted one in each wing outboard of undercarriage, operated by a mechanical pneumatic system from the pilot's control column. The rear gunner/radio operator operated one 7.92 mm (.312 in) MG 15 machine gun for defensive purposes.

The engine and propeller had automatic controls, and an auto-trimmer made the aircraft tail-heavy as the pilot rolled over into his dive, lining up red lines at 60°, 75° or 80° on the cockpit side window with the horizon and aiming at the target with the sight of the fixed gun. The heavy bomb was swung down clear of the propeller on crutches prior to release.

Diving procedure

Flying at 4,600 m (15,100 ft), the pilot located his target through a bomb sight window in the cockpit floor. The pilot moved the dive lever to the rear, limiting the "throw" of the control column. The dive brakes were activated automatically, the pilot set the trim tabs, retarded his throttle and closed the coolant flaps. The aircraft then rolled 180°, automatically nosing the aircraft into a dive. Red tabs protruded from the upper surfaces of the wing as a visual indicator to the pilot that, in case of a g-induced black-out, the automatic dive recovery system would be activated. The Stuka dived at a 60-90° angle, holding a constant speed of 500–600 km/h (350-370 mph) due to dive-brake deployment, which increased the accuracy of the Ju 87's aim.

When the aircraft was reasonably close to the target, a light on the contact altimeter came on to indicate the bomb-release point, usually at a minimum height of 450 m (1,480 ft). The pilot released the bomb and initiated the automatic pull-out mechanism by depressing a knob on the control column. An elongated U-shaped crutch located under the fuselage swung the bomb out of the way of the propeller, and the aircraft automatically began a 6 g pullout. Once the nose was above the horizon, dive brakes were retracted, the throttle was opened, and the propeller was set to climb. The pilot regained control and resumed normal flight. The coolant flaps had to be reopened quickly to prevent overheating. The automatic pull-out was not liked by all pilots. Helmut Mahlke later said that he and his unit disconnected the system because it allowed the enemy to predict the Ju 87s recovery pattern and height, making it easier for ground defences to hit an aircraft.

Physical stress on the crew was severe. Human beings subjected to more than 5 g forces in a seated position will suffer vision impairment in the form of a grey veil known to Stuka pilots as "seeing stars". They lose vision while remaining conscious; after five seconds, they black out. The Ju 87 pilots experienced the visual impairments most during "pull-up" from a dive.

Eric "Winkle" Brown RN, a British test pilot and Commanding Officer of Captured Enemy Aircraft Flight section, tested the Ju 87 at RAF Farnborough. He said of the Stuka, "I had flown a lot of dive-bombers and it’s the only one that you can dive truly vertically. Sometimes with the dive-bombers...maximum dive is usually in the order of 60 degrees.. When flying the Stuka, because it’s all automatic, you are really flying vertically... The Stuka was in a class of its own."

Once the Stuka became too vulnerable to fighter opposition on all fronts, work was done to develop a replacement. None of the dedicated close-support designs on the drawing board progressed far due to the impact of the war and technological difficulties. So the Luftwaffe settled on the Focke-Wulf Fw 190 fighter aircraft, with the Fw 190F becoming the ground-attack version. The Fw 190F started to replace the Ju 87 for day missions in 1943, but the Ju 87 continued to be used as a night nuisance-raider until the end of the war.

Tuesday, 29 April 2014

Junkers JU 87 Stuka Survivors and replicas (Stuka Part 1)

Airworthy Junkers JU 87 Stuka - 1940s Terror of the Skies

Survivors and Replicas

Steve Scheckter recently placed a photo of a replica/model Ju87 on Facebook, apparently flying over European  countryside. I guessed it was a Photoshop picture, as I'm reasonably sure there are no airworthy Ju 87 in the world. Well, then again, that was also said of the Mosquito, so I did a bit of research on the history and current facts, and came up with this:

History (Wiki) :

The Junkers Ju 87 or Stuka (from Sturzkampfflugzeug, "dive bomber") was a two-man (pilot and rear gunner) German dive bomber and ground-attack aircraft. Designed by Hermann Pohlmann, the Stuka first flew in 1935 and made its combat debut in 1936 as part of the Luftwaffe's Condor Legion during the Spanish Civil War.

The aircraft was easily recognisable by its inverted gull wings and fixed spatted undercarriage, upon the leading edges of its faired main gear legs were mounted the Jericho-Trompete ("Jericho Trumpet") wailing sirens, becoming the propaganda symbol of German air power and the blitzkrieg victories of 1939–1942. The Stuka's design included several innovative features, including automatic pull-up dive brakes under both wings to ensure that the aircraft recovered from its attack dive even if the pilot blacked out from the high acceleration.

Although sturdy, accurate, and very effective against ground targets, the Ju 87, like many other dive bombers of the war, was vulnerable to modern fighter aircraft. Its flaws became apparent during the Battle of Britain; poor manoeuvrability and a lack of both speed and defensive armament meant that the Stuka required heavy fighter escort to operate effectively.

The Stuka operated with further success after the Battle of Britain, and its potency as a precision ground-attack aircraft became valuable to German forces in the Balkans Campaign, the African and Mediterranean theaters and the early stages of the Eastern Front campaigns where Soviet fighter resistance was disorganised and in short supply.

Once the Luftwaffe lost air superiority on all fronts, the Ju 87 once again became an easy target for enemy fighter aircraft. In spite of this, because there was no better replacement, the type continued to be produced until 1944. By the end of the conflict, the Stuka had been largely replaced by ground-attack versions of the Focke-Wulf Fw 190, but was still in use until the last days of the war. An estimated 6,500 Ju 87s of all versions were built between 1936 and August 1944.

Some notable airmen flew the Ju 87. Oberst Hans-Ulrich Rudel was the most successful Stuka ace and the most highly decorated German serviceman of the Second World War. The vast majority of German ground attack aces flew this aircraft at some point in their careers.

See a separate post on the history: Ju 87 Stuka History Part 2

Two intact Ju 87s survive:

Ju 87 R-2/Trop. Werk Nr. 5954

This aircraft is displayed in the Chicago Museum of Science and Industry. It was abandoned in North Africa and found by British forces in 1941. The Ju 87 was donated by the British government and sent to the USA during the war. It was fully restored in 1974 by the EAA of Wisconsin.

Ju 87 G-2, Werk Nr. 494083

A later, ground-attack variant, this is displayed at the Royal Air Force Museum in London; it was captured by British troops in Germany in 1945. It is thought to have been built in 1943–1944 as a D-5 before being rebuilt as a G-2 variant, possibly by fitting G-2 outer wings to a D-5 air frame. After the war, it was one of 12 captured German aircraft selected by the British for museum preservation.

 In 1967, permission was given to use the aircraft in the film Battle of Britain and it was repainted and modified to resemble a 1940 variant of the Ju 87. The engine was found to be in excellent condition and there was little difficulty in starting it, but returning the aircraft to airworthiness was considered too costly (and risky)  for the filmmakers, and ultimately, models were used in the film to represent Stukas. (see below)

 In 1998, the film modifications were removed, and the aircraft returned to the original G-2 configuration.

Junkers Ju 87 R-2 Werk Nr. 0875709 is owned by Paul Allen's Flying Heritage Collection (FHC) and is believed to be under a long-term restoration to fly. It served bearing the Stammkennzeichen of LI+KU with 1./St.G.5, and was recovered to the United Kingdom in 1998 before being sold to the FHC. It is likely to be the best candidate for an airworthy restoration.

Other aircraft survive as wreckage, recovered from crash sites.

1. The Deutsches Technikmuseum in Berlin has the wreckage of two complete aircraft that were recovered from separate crash sites near Murmansk in 1990 and 1994.

These wrecks were purchased from New Zealand collector Tim Wallis, who originally planned for the remains to be restored to airworthy, in 1996.

The Sinsheim Auto & Technik Museum displays the remains of an aircraft that crashed near Saint-Tropez in 1944 and was raised from the seabed in 1989.

2. In October 2006, a Ju 87 D-3/Trop. was recovered underwater, near Rhodes, Greece:

Ju-87 STUKA salvaged in Greece-15.jpg

Markings still visible after almost 70 years under water

Ju-87 STUKA salvaged in Greece-11.jpg

Ju-87 STUKA salvaged in Greece-2.jpg

More on the history of this aircraft: 

According to a combination of available historical data, it appears that the aircraft is most probably S7+GM (100375), crewed by Lt. Rolf Metzger & Uffz. Hans Sopnemann - both MIA), which was shot down on 9 October 1943.

The Hellenic Air Force web-site tells us this about this aircraft:
"On that very day the II/St.G. 3 lost a total of nine Ju 87D-3/Trop when they were intercepted during their mission against Royal Navy and Hellenic Navy ships in the Aegean. Of these nine, seven crashed into the sea and two made emergency landings on Rodos. A week before, German troops had landed on the island of Kos, which fell the next day. On 9 October 1943, HMS cruiser "Carlisle" and other destroyers, returning from a sweep west of Kos, were dive-bombed SW of Rodos Island by a formation of Ju-87 Stukas. "Carlisle" was seriously damaged and HMS destroyer "Panther" was sunk. Most of her crew were saved by the RHN destroyer "Miaoulis", which has also claimed firing against the Ju-87 formation and probably hit a couple of them."

3.  Junkers Ju 87 B-2 9801 (serial number: 0406) is under reconstruction at Yugoslav Aeronautical Museum.

5. The fuseage of a Junkers Ju 88 was raised 6 miles off the coast of the German Island of Rügen in June 2012, the team of German Army researchers having thought it to be a Stuka. The two Junkers planes shared several parts, including the engines, and from the way it sat in the seabed it reportedly appeared to have been a Ju 87.

British Flying Replicas

 During the filming of 'The Battle of Britain' in 1968, serious thought was given to using the Hendon Stuka for the Ventnor radar bombing scenes. At the time the Stuka was part of the Air Historic Branch's collection of German aircraft, and it was decided by them that the Ju 87 was too valuble to risk (It was unique at that point).

The cost of getting the aircraft airworthy would have been prohibitive, but they did get the engine running, and this was recorded for use on the films soundtrack. Next they bought 4 Percival Procters for conversion to 'lookalikes'. The work was carried out by Viv Bellamy and entailed a major redesign of the cockpit glazing, new rectangular tail plane, rear fuselage cut down and new centre section built to pass for the distinctive Stuka cranked wing. 

The conversion was pretty convincing but, when flight tested by Bellamy, they did not fly well and were not used for filming. Their places were taken by large-scale radio controlled models which bombed the Ventnor film set constructed at The Mound near Dover.

New Zealand Static replica:

The full-size replica Stuka built by Lester Hope and his team of dedicated volunteers for Classic Fighters, was moved to its new location outside the Omaka Aviation Heritage Centrey. Here it joins its contemporary adversary, the replica Hawker Hurricane. 

Frankfurt Airport Static Replica:


Ukranian scaled down  flying replica, one of many in the world.

Wednesday, 16 April 2014

Vampires in Air Race in NZ Warbirds over Wanaka

Jet-Races on at Warbirds over Wanaka 

(Weather permitting)

Peter Vause

Peter Vause, who has a L39 Albatross, and Brett Emeny in his de Havilland Vampire will join Christchurch pilot Paul Hughan, who also has a de Havilland, to take on the Americans.
It is the first time this type of jet air racing has been done in New Zealand, Emeny says.
"We fly round a race track, it's an eight-mile course. The circuit gets down to 100ft at 700km an hour.
"It's good fun. It's going to be cool. You get around that eight-mile course in less than 1.5 minutes. It's about six miles a minute. We're going to do six laps of the course and see how we go."
The Americans will be flying Russian L-29 trainer  jets, he said.
All six jets will start in a row, a bit like in a horse race, and come in from behind the airfield in a straight line.
"When you get cleared to start, you open the throttle and go for the first pylon.
"They've got these blow-up pylons that stand up and you fly around and zoom around those."
The six jets will be within a few metres of each other at times, Emeny said.
"It should be a good spectacle." 
L-29 Delfin

The American pilots race at the Reno Air Races in Nevada.
"They used do it with high-powered prop-driven fighters and now they are racing jets as well. It's the fastest motor sport there is."
The de Havilland Vampires were the first single-engine jet fighters ever built and were first flown in 1943, Emeny said.
They were also flown by 75 Squadron at Ohakea in the 1950s.
"Mine was built in 1958. It was one of the last ones built."
Vause, an engineer, got his L39 Albatross, which was built in 1983, 10 years ago.
"It's a Czech-built jet trainer used by all of the Eastern bloc air forces. They became available in relatively large numbers when the Russian empire collapsed in 1992. Air forces started shedding their aeroplanes so they could afford to pay people."
He bought it because he wanted to fly "something that went fast".
Vause and Emeny flew their jets to Wanaka yesterday.
Warbirds Over Wanaka starts on Good Friday and finishes on Sunday.
The first jet race will be on Friday.

L39 Albatross
Just in case anyone had forgotten the biggest warbirds airshow in the southern hemisphere starts on Saturday, six racing jet aircraft flew low, slow and quietly over Wanaka's lake frontage yesterday afternoon.

Under leaden skies, the three Aero L-29s, two De Havilland Vampires and an Aero L-39 have been practising for their starring role in the Warbirds Over Wanaka International Airshow.

On Saturday and Sunday, they will race wingtip-to-wingtip around an ''aerial racetrack'' marked by large orange pylons, in a type of race rarely seen beyond the Reno Air Race in the United States.

Much of the banter among the American and New Zealand jet racing pilots at Wanaka Airport yesterday revolved around the differing performance characteristics of the aircraft.

The Vampires are faster; the Aeros take the corners better.

And one of the American pilots was a little bemused at having a speedometer reading kmh rather than mph.

Spectators can expect the fastest of the six jets to hit 640kmh [397mph] on the home straight.

Wanaka Airport has been filling up this week with aircraft of all shapes and sizes - a Spitfire has arrived, and a Mustang, a Corsair and the Yaks are in the plane park.

Late yesterday afternoon, the French Air Force contingent arrived in its Casa (mini Hercules) military transport aircraft.

Infrastructure construction was a day ahead of the last show two years ago and was going ''really well'', he said.

Bad weather further north had created ''some challenges'' getting aircraft to Wanaka from the North Island.

While the ''vast majority'' had arrived, Mr Taylor said, there was still doubt yesterday over whether the Harvard aerobatics team would make the show.

''If the Harvards can't make it, it will be a real shame, but it won't affect the airshow at all.''

Mr Taylor said the weather forecast for the weekend indicated better weather for Central Otago than for elsewhere but there were still likely to be ''a few light showers''. An ''old-timer'' had told him a ''good thing'' about grey skies was that it made planes easier to see.

''Also, it's not such a strain looking into the hot sun all day.''

The first official event on the show programme is a free World War 1 ''dogfight'' over Lake Wanaka on Good Friday afternoon, involving six biplanes and triplanes.

Boating has been banned from the lake area below during the performance.

Mr Taylor said the New Zealand Air Force would be doing a ''special event'' at the end of the dogfight, but declined to elaborate.

''You've got to be there to see it. It will be pretty spectacular.''

In addition to the action in the air over Easter, the best jet sprint boats in the country will be competing in the finals of the national championships on a course next to Wanaka Airport tomorrow evening.

Race organiser Chris Munro said yesterday the event was timed to fit in around the warbirds show.

The last jet sprint event at Wanaka attracted a crowd of 6000-7000 people.

Canterbury driver Peter Caughey leads the way in the superboat championship and Sam Newdick, of Hamilton the group A championship.

Condensed article from Otago Daily and Southland Times reports - no copyright infringement intended

Tuesday, 15 April 2014

Silent Wings: The AS 51 Horsa Glider

The Airspeed 51 Horsa Glider

As part of the 70th Anniversary of the D-Day Normandy Landings our Wargames club is re-fighting the Sword Beach Landings of 1944.

This led me to research the history of the British 6th Airbourne and the Horsa Glider:
(Mostly from Wiki)

The Airspeed AS.51 Horsa was a British World War II troop-carrying glider built by Airspeed Limited and subcontractors and used for air assault by British and Allied armed forces. It was named after Horsa, the legendary 5th century conqueror of southern Britain.

The German military was a pioneer in the use of airborne operations, conducting several successful operations during the Battle of France in 1940, including the use of glider-borne troops in the Battle of Fort Eben-Emael and Crete. Impressed by the success of Germans airborne operations, the Allied governments decided to form their own airborne formations.This would eventually lead to the creation of two British airborne divisions, as well as a number of smaller units.

Tarrant Rushton Airfield, with gliders lined up

When the equipment for the airborne forces was under development, it was decided  that gliders would be an integral component; used to transport troops and heavy equipment. The first glider to be designed and produced was the General Aircraft Hotspur. Several problems were found with the Hotspur's design, the primary one being that the glider did not carry sufficient troops.

Hotspur glider 

Tactically it was believed that airborne troops should be landed in groups far larger than the eight the Hotspur could transport, and also the number of aircraft required to tow the gliders needed to carry larger groups would be impractical. There were also concerns that the gliders would have to be towed in tandem if used operationally, which would be extremely difficult during nighttime and through cloud formations. So the Hotspur was relegated to training duties, leading to the development of several other types of glider, including a 25-seater assault glider which became the Airspeed Horsa.

Initially it was planned that the Horsa would be used to transport paratroopers who would jump from doors installed on either side of the fuselage, and that the actual landing would be a secondary role; however the idea was soon dropped, and it was decided to simply have the glider land airborne troops. An initial order was placed for 400 of the gliders in February 1941, and it was estimated that Airspeed should be able to complete the order by July 1942.  Enquiries were made into the possibility of a further 400 being produced in India for use by Indian airborne forces, but this was abandoned when it was discovered the required wood would have to be imported into India at a prohibitive cost. Five prototypes were ordered with Fairey Aircraft producing the first two prototypes for flight testing while Airspeed completed the remaining prototypes to be used in equipment and loading tests. The first prototype (DG597) towed by an Armstrong Whitworth Whitle,  took flight on 12 September 1941 with George Errington at the controls.

Inspirational diorama (Great North Roads, Carl Hruska)

Production of the Horsa commenced in early 1942, and by May some 2,345 had been ordered by the Army for use in future airborne operations. The glider was designed from the outset to be built in components with a series of 30 sub-assemblies required to complete the manufacturing process. Manufacturing was intended primarily to use wood-crafting facilities not needed for more urgent aviation production, and as a result production was spread across separate factories, which consequently limited the likely loss in case of German attack. he designer A. H. Tiltman said that the Horsa "went from the drawing board to the air in ten months, which was not too bad considering the drawings had to be made suitable for the furniture trade who were responsible for all production."

The initial 695 gliders were manufactured at Airspeed's factory in Christchurch, Hampshire, with subcontractors producing the remainder. These included Austin Motors and furniture manufacturers. The subcontractors did not have airfields to deliver the gliders from, and sent the sub-assemblies to RAF Maintenance Units for final assembly. 4000 to 5000 Horsas were built in all.

The Horsa Mark I had a wingspan of 88 feet (27 m) and a length of 67 feet (20 m), and when fully loaded weighed 15,250 pounds (6,920 kg).

The Horsa was considered sturdy and very manoeuvrable for a glider. Its design was based on a high-wing cantilever monoplane with wooden wings and a wooden semi mono-coque fuselage. The fuselage was built in three sections bolted together, the front section held the pilot's compartment and main freight loading door, the middle section was accommodation for troops or freight, the rear section supported the tail unit. It had a fixed tricycle landing gear and it was one of the first gliders equipped with a tricycle undercarriage for take off. On operational flights the main gear could be jettisoned and landing was then made on the castoring nose wheel and a sprung skid under the fuselage.

A radio-controlled model, probably as close we'll ever get to seeing a Horsa fly again

The wing carried large "barn door" flaps which, when lowered, made a steep, high rate-of-descent landing possible — allowing the pilots to land in constricted spaces. The pilot's compartment had two side-by-side seats and dual controls. Aft of the pilot's compartment was the freight loading door on the port side. The hinged door could also be used as a loading ramp. The main compartment could accommodate 15 troops on benches along the sides with another access door on the starboard side.

The fuselage joint at the rear end of the main section could be broken on landing to assist in rapid unloading of troops and equipment. Supply containers could also be fitted under the center section of the wing, three on each side.

The later AS 58 Horsa II had a hinged nose section, reinforced floor and double nose wheels to support the extra weight of vehicles. The tow cable was attached to the nose wheel strut, rather than the dual wing points of the Horsa I.

The Airborne Forces Experimental Establishment and 1st Airlanding Brigade began loading trials with the prototypes in March but immediately ran into problems. Staff attempted to fit a jeep into a prototype, only to be told by Airspeed personnel present that to do so would break the glider's loading ramp, as it had only been designed to hold a single motorbike. With this lesson learnt, 1st Airlanding Brigade subsequently began sending samples of all equipment required to go into Horsas to Airspeed, and a number of weeks were spent ascertaining the methods and modifications required to fit the equipment into a Horsa.

I also found this great video footage:  Last flight of the Assault Gliders

Operational history
With up to 30 troop seats, the Horsa was much bigger than the 13-troop American Waco CG-4A (known as the Hadrian by the British), and the 8-troop General Aircraft Hotspur glider which used for training duties only. Instead of troops, the AS 51 could carry a jeep or a 6 pounder anti tank gun.

The Horsa was first used operationally on the night of 19/20 November 1942 in the unsuccessful attack on the German Heavy Water Plant at Rjukan in Norway (Operation Freshman). The two Horsa gliders, each carrying 15 sappers, and one of the Halifax tug aircraft, crashed in Norway due to bad weather. All 23 survivors from the glider crashes were executed on the orders of Hitler, in a flagrant breach of the Geneva Convention which protects POWs from summary execution.

In preparation for further operational deployment, 30 Horsa gliders were air-towed by Halifax bombers from Great Britain to North Africa but three aircraft were lost in transit. On 10 July 1943, 27 surviving Horsas were used in Operation Husky, the invasion of Sicily.

Large numbers (estimated at over 250) were subsequently used in Battle of Normandy; in the British Operation Tonga and American operations. The first units to land in France, during the Battle of Normandy, was a coup de main force carried by 6 Horsas that captured Pegasus Bridge in Operation Deadstick, over the Caen canal, and a further bridge over the River Orne.

Ranville - note "Rommel's Asparagus" - anti glider posts

320 Horsas were used in the first lift and a further 296 Horsas were used in the second lift. Large numbers were also used for Operation Dragoon and Operation Market Garden, both in 1944, and Operation Varsity in March 1945; the final operation for the Horsa when 440 gliders carried soldiers of the 6th Airborne Division across the Rhine.

Horsas at Ranville

In operations, the Horsa was towed by various aircraft: four engined heavy bombers displaced from operational service such as the obsolete Short Stirling and Handley Page Halifax, the Armstrong Whitworth Albemarle and Armstrong Whitworth Whitley twin-engined bombers, as well as the US Douglas C-47 Skytrain/Dakota (not as often due to the weight of the glider, however in Operation Market Garden, a total of 1,336 C-47s along with 340 Stirlings were employed to tow 1,205 gliders,) and Curtiss C-46 Commando. They were towed with a harness that attached to points on both wings, and also carried an intercom between tug and glider. The glider pilots were usually from the Glider Pilot Regiment, part of the Army Air Corps, although Royal Air Force pilots were used on occasion.

British airborne troops guarding a road crossing, Horsas in background

The United States Army Air Forces (USAAF) acquired approximately 400 Horsas in a form of "reverse" Lend-Lease. A small number of Horsa Mk IIs were obtained by the Royal Canadian Air Force for post-Second World War evaluation at CFB Gimli, Manitoba. Three of these survivors were purchased as surplus in the early 1950s and ended up in Matlock, Manitoba where they were eventually scrapped. A small number of Horsas were also evaluated postwar in India. Due to low surplus prices in the UK, many were bought and converted to travel trailers and vacation cottages.

Horsa fuselage being converted into a "lovely little flat"

On 5 June 2004, as part of the 60th anniversary commemoration of D-Day, Prince Charles unveiled a replica Horsa on the site of the first landing at Pegasus Bridge, and talked with Jim Wallwork, the first pilot to land the aircraft on French soil during D-Day.

Replica at Pegasus Bridge

Ten replicas were built for use in the 1977 film A Bridge Too Far, mainly for static display and set-dressing, although one Horsa was modified to make a brief "hop" towed behind a Dakota at Deelen, the Netherlands. During the production, seven of the replicas were damaged in a wind storm; the contingent were repaired in time for use in the film. Five of the Horsa "film models" were destroyed during filming with the survivors sold as a lot to John Hawke, aircraft collector in the UK. Another mock-up for close-up work came into the possession of the Ridgeway Military & Aviation Research Group and is stored at Welford, Berkshire.

AS.51 Horsa I
Production glider with cable attachment points at upper attachment points of main landing gear.
AS.52 Horsa
Bomb-carrying Horsa; project cancelled prior to design/production
AS.53 Horsa
further development of the Horsa not taken up.
AS.58 Horsa II
Development of the Horsa I with hinged nose, to allow direct loading and unloading of equipment, twin nose wheel and cable attachment on nose wheel strut.



Belgian Army - One aircraft only.
Royal Canadian Air Force
Indian Air Force
Portuguese Air Force
Turkish Air Force
 United Kingdom
Army Air Corps
Glider Pilot Regiment
Royal Air Force
No. 670 Squadron RAF
 United States
United States Army Air Forces

An Airspeed Horsa Mark II (KJ351) is preserved at the Museum of Army Flying in Hampshire, England. The Assault Glider Trust is building a replica at RAF Shawbury using templates made from original components found scattered over various European battlefields and using plans supplied by BAE Systems (on the condition that the glider must not be flown).

The Dakota leaves RAF Shawbury

The Assault Glider Trust  (Clicky for link) Horsa being transported from RAF Shawbury

More info and pics from Chalk Living History

Although there is some difference of opinion (now being researched), the replica at Pegasus Bridge is believed to incorporate a forward fuselage section retrieved from Cholsey, Oxfordshire, which had served as a dwelling for over 50 years. This relic was recovered from Cholsey around 2001 by the Mosquito Aircraft Museum, of London Colney, where it was stored until being transferred to Pegasus Bridge. The airframe is not believed to have seen active service.

Specifications (AS 51)
Data from British Warplanes of World War II

General characteristics
Crew: 2
Capacity: 25 troops (20-25 troops were the "standard" load)
Length: 67 ft 0 in (20.43 m)
Wingspan: 88 ft 0 in (26.83 m)
Height: 19 ft 6 in (5.95 m)
Wing area: 1,104 ft² (102.6 m²)
Empty weight: 8,370 lb (3,804 kg)
Loaded weight: 15,500 lb (7,045 kg)

Maximum speed: 150 mph on tow; 100 mph gliding (242 km/h / 160 km/h)
Wing loading: 14.0 lb/ft² (68.7 kg/m²)

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