Hafner Rotabuggy (Flying Jeep)

[Cy-27]

Attached are a pair of photos of a replica of the Hafner Rotabuggy (see http://www.secretprojects.co.uk/forum/index.php/topic,4022.msg31649.html#msg31649 for period photo) taken recently at the Museum of Army Flying at Middle Wallop. It was a British experiment that took a Willys jeep and gave it a flight capability. The idea was to produce a method of air-dropping vehicles and was designed by Raoul Hafner of the Airborne Forces Experimental Establishment (AFEE). The replica on display was built by the Wessex Aviation Society.

The sole example of the Hafner Rotabuggy was also known as the Malcolm Rotaplane and the ML 10/42 Flying Jeep (Air Ministry specification 10/42 for a "Special Rotating Wing Glider"). Originally named the Blitz Buggy, it was dropped for the Rotabuggy to keep in-line with the Hafner series naming (Rotachute and Rotatank - see http://www.secretprojects.co.uk/forum/index.php/topic,1291.msg192255.html#msg192255 and http://www.secretprojects.co.uk/forum/index.php/topic,724.msg19746.html#msg19746).

Tests found that a Willys MB could be dropped from heights up to 2.35 metres (7.7 ft) without damage to the vehicle. It had a rotor was along with a tail fairing and twin fins fitted to the jeep. The design had no rudders. Two men were required to pilot the aircraft, a driver and a pilot who would fly the airborne contraption using a control column.

The first trial was conducted on 16 November 1943, with the unit being towed behind a lorry, but the vehicle could not get enough speed to put the "Rotabuggy" in the air. A more powerful 4.5 litre Bentley was used on 27 November to finally allow the machine to become airborne and in test could obtain glide speeds of 45 mph. Later tests were to be made towed behind an Armstrong-Whitworth Whitley bomber.

The tests showed that the device was prone to severe vibration at speeds greater than 45 miles per hour (72 km/h). Improvements led to the Rotabuggy achieving a flight speed of 70 mph (113 km/h) on 1 February 1944.

The last test flight occurred in September 1944, where the unit flew for 10 minutes at an altitude of 400 feet (121.9 m) and a speed of 65 mph (105 km/h), after being released by a Whitley bomber.

With the advent of larger tactical gliders that could carry vehicles (such as the Waco Hadrian and Airspeed Horsa) the Rotabuggy development was stopped and the project cancelled.

General characteristics

Length: 21 ft 0 in (6.40 m)
Width: 9 ft 6 in (2.90 m)
Height to top of rotor hub: 6 ft 9 in (2.06 m)
Main rotor diameter: 46 ft 8 in (14.22 m) [Museum info board quotes 44 ft (12.19 m)]
Main rotor area: 1,711 sq ft (159.0 m2)
Empty weight: 2,125 lb (964 kg) (Jeep only)
Gross weight: 3,110 lb (1,411 kg)
Maximum speed: 150 mph (241 km/h 130 knots)
Estimated Cruise speed: 80 mph (129 km/h 700 knots)
Rate of sink at 48 mph (77 km/h): 960 ft/min (4.9 m/s)
Rate of sink at 150 mph (240 km/h): 1,980 ft/min (10.1 m/s)

Source:

The British Aircraft Specification File by K Meekcoms and E B Morgan (Air Britain 1994) ISBN 0851302203
Nothing Ventured article by Philip Jarrett (Aeroplane Monthly October 1991)
Exhibit Information Board Museum of Army Flying (Middle Wallop Hampshire SO20 8DY)

 

[Cy-27]

There was a detailed article on the Hafner Rotabuggy in Aeroplane Monthly (October 1991) written by Philip Jarrett as part of his Nothing Ventured series.

The piece included a plan drawing, a series of images of the machine in flight and a photograph of the 'cockpit' - see below.

 

[Grey Havoc]

B)

 

[Grey Havoc]

Perhaps not quite the same form of Jumping Jeep', but stumbled across this from an old Copy of Air Pictorial.

 

[Nik]

"This is but 'Proof of Concept': Next, a Bren Carrier (on wheeled trailer), then a 'Tank Destroyer' !!"

Upside, if crazy but works, YAY !! Downside, I think it needed four blades...

 

[robunos]

Downside, I think it needed four blades...

It only has two blades because it has a a simple, 'Benson-Type', teetering rotor hub. If you go to four blades, that means a double hub . . .

cheers,
Robin.

 

[robinbird]

Just joined Secret Projects and this is to introduce myself. My late father Bob Bird photographed trials of the Flying Jeep at RAF Sherburn and simialr secret projects during WW2. He was a Ministry photographer assigned to similar secret trials, firstly with the Marine Aircraft Experimental Establishment, Helensburgh, then the Airborine Forces Experimental Establishment, Sherburn and Beaulieu. I am interested in anything regarding MAEE/AFEE, or forums I have missed. Pictures from a book I published about dad's war-robin

 

[robinbird]

My late father was the photographer of the flying jeep trials at Sherburn, these pictures were taken by him. Bob Bird was employed by the Ministry of Aircraft Production. He was assigned to secret projects conducted by Airborne Forces Experimental Establishment. In 2004 I published a book about him entitled Top Secret War Bird of WW11. To take some pictures dad sat in the back of a Bentley sports used as the tow car. Sqd Ldr Ian Little was the test pilot. The Bentley was said to be an ex Le Man car. My research suggests an ex Birkin Bentley. Another secret project was the experimental Baynes Bat tailless glider, a scaled down version of a proposed glider wing that could carry a tank. The test pilot was Robert Kronfeld, the record breaking glider pilot before the war
robin bird

 

[Justo Miranda]

Rotabuggy details

 

[Justo Miranda]

Hafner Rotachute

 

[Justo Miranda]

Flying Valentine

 

[robinbird]

Dad photographed trials at AFEE Sherburn in Elmet and at Marine Experimental Establishment, Helensburgh, before that. Both the Rotachute and Flying Jeep were flown by Sqd Ldr Ian Little, post war Little was known for economics as a professor of Oxford University. Dad's photographs are in the National Archives, Kew, attached to MAP reports

 

[nuuumannn]

There's a Rotorchute at the Museum of Army Flying as well. Rotorbuggy for interest's sake even though it's been posted before.

 

[dan_inbox]

Flying Valentine

Some art on the Rotatank concept is at https://www.dingeraviation.net/rota/hafnerrotas.html (scroll down).
I cannot make sense out of the described idea that the Rotatank would need to be towed by a Lancaster itself towed by a C-47 to get airborne. If it is any true, no wonder the idea was abandoned.

 

[robinbird]

Attached are a pair of photos of a replica of the Hafner Rotabuggy (see http://www.secretprojects.co.uk/forum/index.php/topic,4022.msg31649.html#msg31649 for period photo) taken recently at the Museum of Army Flying at Middle Wallop. It was a British experiment that took a Willys jeep and gave it a flight capability. The idea was to produce a method of air-dropping vehicles and was designed by Raoul Hafner of the Airborne Forces Experimental Establishment (AFEE). The replica on display was built by the Wessex Aviation Society.

The sole example of the Hafner Rotabuggy was also known as the Malcolm Rotaplane and the ML 10/42 Flying Jeep (Air Ministry specification 10/42 for a "Special Rotating Wing Glider"). Originally named the Blitz Buggy, it was dropped for the Rotabuggy to keep in-line with the Hafner series naming (Rotachute and Rotatank - see http://www.secretprojects.co.uk/forum/index.php/topic,1291.msg192255.html#msg192255 and http://www.secretprojects.co.uk/forum/index.php/topic,724.msg19746.html#msg19746).

Tests found that a Willys MB could be dropped from heights up to 2.35 metres (7.7 ft) without damage to the vehicle. It had a rotor was along with a tail fairing and twin fins fitted to the jeep. The design had no rudders. Two men were required to pilot the aircraft, a driver and a pilot who would fly the airborne contraption using a control column.

The first trial was conducted on 16 November 1943, with the unit being towed behind a lorry, but the vehicle could not get enough speed to put the "Rotabuggy" in the air. A more powerful 4.5 litre Bentley was used on 27 November to finally allow the machine to become airborne and in test could obtain glide speeds of 45 mph. Later tests were to be made towed behind an Armstrong-Whitworth Whitley bomber.

The tests showed that the device was prone to severe vibration at speeds greater than 45 miles per hour (72 km/h). Improvements led to the Rotabuggy achieving a flight speed of 70 mph (113 km/h) on 1 February 1944.

The last test flight occurred in September 1944, where the unit flew for 10 minutes at an altitude of 400 feet (121.9 m) and a speed of 65 mph (105 km/h), after being released by a Whitley bomber.

With the advent of larger tactical gliders that could carry vehicles (such as the Waco Hadrian and Airspeed Horsa) the Rotabuggy development was stopped and the project cancelled.

General characteristics

Length: 21 ft 0 in (6.40 m)
Width: 9 ft 6 in (2.90 m)
Height to top of rotor hub: 6 ft 9 in (2.06 m)
Main rotor diameter: 46 ft 8 in (14.22 m) [Museum info board quotes 44 ft (12.19 m)]
Main rotor area: 1,711 sq ft (159.0 m2)
Empty weight: 2,125 lb (964 kg) (Jeep only)
Gross weight: 3,110 lb (1,411 kg)
Maximum speed: 150 mph (241 km/h 130 knots)
Estimated Cruise speed: 80 mph (129 km/h 700 knots)
Rate of sink at 48 mph (77 km/h): 960 ft/min (4.9 m/s)
Rate of sink at 150 mph (240 km/h): 1,980 ft/min (10.1 m/s)

Source:

The British Aircraft Specification File by K Meekcoms and E B Morgan (Air Britain 1994) ISBN 0851302203
Nothing Ventured article by Philip Jarrett (Aeroplane Monthly October 1991)
Exhibit Information Board Museum of Army Flying (Middle Wallop Hampshire SO20 8DY)

 

[robinbird]

ps the rotor blades were made by Morris Furniture Glasgow. The company worked on experimental projects for AFEE and MAEE including models of the SR1 seaplane jet. Mr Morris is pictured on one image standing next to the Flying Jeep at Sherburn

 

[robinbird]

Thank you for the feedback. I visited the museum several years ago and left a stock of my books that then 'took off' somewhere. As a pre war MG owner, I am interested in the story of the 'Birkin' Bentley and where it came from. After the Jeep trials it was used as a runabout by AFEE. Post war it was returned to the dealership and is now part of our motoring heritage, an expensive example at that! Like the Jeep, the Bentley was registered as an aircraft at AFEE. I do not think it was given a RAF serial number. Test pilot Ian Little was nearly killed flying the jeep. Like the Bentley the Jeep was later used as a workhorse by AFEE. At Beaulieu the Jeep towed a trailer to launch the Focke Achgelis Fa330. Post war Little became well known for his contribution to economics as an Oxford professor. A change of occupation to say the least. Incidentally, Gerstenhauer who flew the Focke Achgelis Drache helicopter to Beaulieu conducted the first trials of the Fa330 for the Luftwaffe in 1942. He did not volunteer to fly any examples at Beaulieu but conducted a few 'trial' flights in his helicopter. Both he and his crew expressed a wish to return to Germany as soon as possible which they did in 1946.

 

[klem]

Rotabuggy under another aspect.

 

[robinbird]

| have a still image from a clip of film of the 'flying jeep' at Beaulieu, which shows it still has the high windscreen

 

[riggerrob]

Flying Valentine

Some art on the Rotatank concept is at https://www.dingeraviation.net/rota/hafnerrotas.html (scroll down).
I cannot make sense out of the described idea that the Rotatank would need to be towed by a Lancaster itself towed by a C-47 to get airborne. If it is any true, no wonder the idea was abandoned.

Just compare gross weights. The Rotabuggy Jeep weighed 3,200 pounds while a Valentine tank weighed more like 32,000 pounds.

For comparison, a Horsa Glider weighed 16,000 pounds fully loaded. Horsas were towed by DC-3s or Albemarle bombers.

The Hamilcar heavy assault glider weighed 36,000 pounds and was usually towed by Halifax bombers. Halifax had similar horsepower as Lancaster (4 RR Merlin engines). Hamilcars were planned to deliver (16,800 pounds) Tetrarch or (16,400 pounds) American-built M-22 Locust (nicknamed "Harry Hopkins") light tanks, but were mainly used to deliver towed anti-tank guns (e.g. British 17-pounder).

Rotors are inherently slower and draggier than fixed wings, ergo they need more horsepwoer to tow.

 

[dan_inbox]

The part which doesn't make sense to me is "a C-47 towing a Lancaster " to tow the rotatank.
Mechanically and operationally, it just sounds so fraught with problems.

 

[robinbird]

At Sherburn all types of tow aircraft and combinations were used to tow the heavy Hamilcar, hence Experimental Establishment. Even the World's best glider pilot had trouble controlling a loaded Hamilcar resulting in a crash that caused him minor injuries. Also AFEE had to use available aircraft and it was not until after D Day they became more available. i.e. Lancasters Halifaxes Stirlings, Hastings. Two Hamilcars were fitted with engines by AFEE, with fuel tanks in the wings, serial numbers LA704 and LA728

 

[robinbird]

Thanks for the x ref Robin. I am happy to stay at Sherburn-in-Elemet and the Flying Jeep.

 

[hesham]

Hi,

The Hafner Rotachute, Rotabuggy and Rotatank projects of WW2

dingeraviation.net

 

[Schneiderman]

The part which doesn't make sense to me is "a C-47 towing a Lancaster " to tow the rotatank.
Mechanically and operationally, it just sounds so fraught with problems.

 

[Nicknick]

There was a detailed article on the Hafner Rotabuggy in Aeroplane Monthly (October 1991) written by Philip Jarrett as part of his Nothing Ventured series.

The piece included a plan drawing, a series of images of the machine in flight and a photograph of the 'cockpit' - see below.

A glide angle of 1:57 ??? I guess this is missing a point, but even 1:5.7 would be quite good for that

 

[robinbird]

Up to D- Day AFEE had difficulty obtaining powerful four engined bombers for conversion into tugs or for airborne drops. They were needed elsewhere. After D-Day the need to drop tanks, jeeps, heavy guns etc was not a priority as reflected by the types of trials carried out. The challenge was then to develop assault gliders and the transportation of troop by aircraft and helicopters.

 

[riggerrob]

There was a detailed article on the Hafner Rotabuggy in Aeroplane Monthly (October 1991) written by Philip Jarrett as part of his Nothing Ventured series.

The piece included a plan drawing, a series of images of the machine in flight and a photograph of the 'cockpit' - see below.

A glide angle of 1:57 ??? I guess this is missing a point, but even 1:5.7 would be quite good for that

A glide angle/ lift-to-drag ratio of 1.57 puts it in the same range as a round parachute, perhaps a high-performance round parachute like a Para-Commander.
OTOH Jalbert-pattern, rectangular, ram-air canopies with an aspect ratio of 2.6 tend to have glide angles in the 2.6 range. They could be trimmed flatter, but then lose the ability to self-recover from stalls.
Yes, we know that elliptical, para-gliders have much higher aspest ratios - and flatter glides - but they do not need to inflate part way down and they lose the ability to self-recover from stalls.

 

[robinbird]

Tests of the Flying Jeep. The Bentley is believed to be Birkin's ex-Le Mans car.

 

[Nicknick]

@riggerrob :
1.57 sound realistic to me, not "1 in 57"

 

[publiusr]

It also gave a roll cage to the Jeep.

I could see upper part of that detachable with bolts, and the tail assembly broken down into a tent…or folding forward over the Jeep for protection against the elements. With modern materials—this needs a fresh look. Keep blades to either side to put across a ditch and drive over it…the top prop-column detached from the roll cage now a gun mount of some kind…