French prototypes

airplane designer and ...unknown hero.

Why do I mention FRENCH in the title? Easy, there was a single Delanne variant in England. I give info about it on a special Lysander P12 page.

A model of the Arsenal - Delanne 10 C-2(got permission to use this picture from the modelclub "Club du Theil", thanks guys)

I quote and translate a few articles I found, thanks to the help of Paul Deweer and Brian Ward.

Based on article in "Air Trails" Oct. 1950:

First there was the order for the commander-fighter, like mentioned in the main page. While making the fighter, there came a requirement from the French Air Ministry for a aerobatic trainer. Delanne saw another possibility for his Duo-Mono design. Delanne got a study contract to prepare himself. But he was confident in his design and proposed a four-fifth scale model of the fighter. This trainer, the 20T-02, was finished in March 1938, before the fighter got finished.

Seems like it should be a good thing to find the old test reports. There were some remarkable results. For instance: a take-off test in which a airplane has to climb over a object of 19,8 m (65 feet) high after 600m (1970 feet) of runway. The airplanes of 1939 barely made it. The trainer crossed it with 33 m (108 feet) to spare.

Test flights in front of officials got him contracts to study the design of a bomber, a glide bomb and ... a giant troop glider.

When the fighter was finished, France was run over by the Germans. The fighter got in the hands of the Germans. Delanne pretended to collaborate; but he did all (to the extreme) to prevent the Germans from using his ideas. The Resistance work of Maurice Delanne is worth a book or ...a movie. He started with altering the technical data so the design became worthless. But there were still the two prototypes. The Germans could use them to regain the correct data. Delanne knew ... he had to destroy them! During a bomb raid, he jumped in the trainer and "tried to taxi it to safety", but ... in fact he rammed the fighter. It happened so hard, both caught fire and Delanne barely could escape. His plan to destroy the prototypes had worked. But the Germans did not totally trust his excuse of "being a bad pilot" and sentenced him to the prison of Siegburg, near Bonn.

When the Allied freed the prisoners, Delanne was reduced to a human wreck of only 36 kg (80 lbs)! He seemed to have been useless during that time. Wrong! Even in prison he was a enemy of the Germans. He sabotages the machines, which produced soldier socks, car engines and hand grenades. I pity the soldiers who used those socks, cars and especially those who used the hand grenades.

Text found in mailinglist

for <>
Subject: Arsenal-Delanne 10 Date

Phew! not the easiest of 'planes to research. It appears Messrs. Green and Swanborough are my only sources. The Salamander book entry appears to be a truncated account of what appeared in the (much) earlier book - War Planes of the Second World War - Fighters, Vol.1, published by Macdonalds back in 1960. I can do no better than reproduce the whole entry - paraphrasing would be pointless, so with due acknowledgement to the maestro, here goes:-

"In 1936 M. Delanne first proposed the use of the tandem-monoplane or Nenadovich biplane configuration for a military aircraft. The tandem mounted wings providing a continuous slot effect were claimed to offer an exceptional c.g. travel and an extremely low stalling speed, and, to prove the claims made for this configuration, the Societe Anonyme Francais de Recherché Aeronautiques built a light tandem two seat monoplane, the Delanne 20, powered by a 180 h.p. Regnier R6 engine. Unfortunately, this aircraft was destroyed on its first test flight on 10th August 1938, but a second Delanne 20 was built and successfully test-flown in March 1939. As the feasibility of the tandem-monoplane arrangement had now been proven, the S.A.F.R.A. furnished, at the request of the Ministere de l'Air, the Arsenal de l'Aeronautique at Villacoublay with full details of the configuration, and the Arsenal commenced the construction of a unique two-seat fighter, the Arsenal-Delanne 10. Apart from the use of slots on the leading edge of the forward wing, the fighter followed closely the configuration of the Delanne 20. Metal stressed-skin construction was employed, the fighter using for the first time a technique known as "contre-plaque-metallique"- a smooth dural skin electrically welded to corrugated sheet. An unusual feature of the design for the period was the fact that the wheel well doors closed once the mainwheels had been extended in order to preserve the airflow over the lower fuselage. The pilot was seated aft of the 132 fuel tank, and the gunner, who faced rearwards, had an exceptional field of vision.

The Arsenal-Delanne 10 prototype had just been completed when Villacoublay was occupied by German forces in June, 1940, and the R.L.M. ordered the French personnel to continue work on the machine. After protracted delays during taxi-ing tests, and modifications to the vertical surfaces and tailwheel, the Arsenal-Delanne 10 finally flew for the first time in October 1941. The undercarriage was successfully retracted on the second flight, and some fifteen test flights were made from Villacoublay during which six hours in the air were logged. After the completion of these trials, the fighter was ferried to a German experimental center (Rechlin?) for further tests, but its subsequent history is unknown."

As far as data is concerned, there appears to be some slight differences between William green's earlier account and the Salamander book, in particular the original figures include:Height: 9 feet, 10 inches Wing Area: 242.188 sq. feet (really, that precise!)Endurance: 1.5 hours at 95% powerService ceiling: 32,810 feet

Graham Salt

A model of the Arsenal - Delanne 10 C-2You can see the control surfaces. Elevators and ailerons on the rear wing.Probably flaps on the front wing.(got permission to use this picture from the model club "Club du Theil", thanks guys)

The Germans knew, near the end of the war, they could use Delanne again. They were in need for a easy to fly single engine jet which could take off on a short airstrip. Just imagine the problem it would have been if the Germans had this stable jet instead of the unstable Heinkel He 162. I dare not guess how many months the end of war would have taken longer. How many deaths more.

Thanks to Paul Deweer I found a drawing and a small text about the Delanne DL 190 glider. This glider was built end 1940 - begin 1941 by SAFRA in Coulommiers in order of the Germans. They wanted to test the Duo-Mono configuration for large transportation gliders with a loading door at the rear. One was finished and taken await by the Germans, the second never got finished. Was Maurice Delanne able to sabotage the plans to make this glider useless?

Delanne DL 190 glider. Made for the Germans to test possible large transportation glider.

Delanne DL 190 glider

  • Span 14 m (45 feet 11 inch)
  • Wing area 24 m2 (258 sq ft)
  • Length 5,75 m (18 feet 10 inch)
  • Weight (total) 580 kg (1278 lbs)
  • Height 2 m (6 feet 6 inch)

I can understand the reason to choose Delanne configurations for transportation airplanes. Easy, wide CG range! Just fill the cargo space without thinking too much about the center of gravity. Sounds easier than calculating the placement of the cargo to get the CG between the limits.

Collection of data found about the French Delanne

Data of the 20T (trainer):

  • Engine: 180HP Regnier 6B-01
  • Span front: 7,86m (25 feet 9 inch)
  • Span rear: 5,66m (5 ft 6 inch)
  • Length: 6,78 m (22 ft 3 inch)
  • Height: 2,20 m (7 ft 2 ½ inch)
  • Total wingarea: 14 m2 (150,7 sq ft)
  • Weight: 978kg (2145 lbs)
  • Top speed: 314km/h (195mph)
  • Climb: 530m (1740 feet)/minute
  • Descend: 5,36m (17,6 feet)/second    at 60km/h (37,5 mph)

another document gives:

  • Weight empty: 730 kg (1609 lb)
  • Weight total: 1031 kg (3382 lb)
  • Speed max.: 262 km/h (163 mph)
  • Speed landing: 60 km/h (37mph)

If you want to make a peanut scale model of the 20T, go see: . You can freely download the plans.

Data of the 10 C2 (fighter):

A lot of data lists give the estimated performances. But those were very optimistic. The engine used performed less than expected. And the weight of the airplane was higher than expected. Both influence performance of the airplane.

  • Length: 6,80 m (22 ft 3 ½ inch)
  • Span 9,25 m (30 ft 4 inch)
  • Wingarea 19,360 m2 (12,788 + 6,572)   208, 4 sq ft (137,7 + 70,7)
  • Weight empty: 1436 kg (3166 lb)
  • Weight total: 2300 kg (5071 lb)
  • Speed max.
    • at 0m: 470 km/h (292 mph)
    • 4000m: 570 km/h (354 mph)
  • Climb to 4 000 m (13 123 ft) in 4 min 33 s
  • Ceiling 10 200 m (33 464 ft)
  • Range 3 h at 450 km/h (280 mph)
  • Climb and clearing a obstacle of 8 m    in 370 m (405 yrd)

(source: le fana de l' aviation, Feb. 1989)