[WWI] Hanriot HD.1

[Phaelen Bleux]

Biplane of the Month Club: November

Hanriot HD.1
Rene Hanriot began in the airplane business by producing license-built versions of Sopwith aircraft, especially the Sopwith 1½ Strutter. This influence can be seen in his first independent design, the HD.1. The plane features many design elements in common with Sopwith planes, such as light but sturdy design, and the “W” cabane strut seen in the 1½ Strutter.
The HD.1 was designed to replace the Nieuport 17. Although maneuverable and easy to fly, it featured an underpowered engine for its day, and lost out to the SPAD S.7 in French service. However, the Italians and Belgians became enamored with the design; both the Belgians and Italians accepted the production run that was rejected by the French (125 and 100 aircraft, respectively), and the Nieuport-Macchi company license-built the HD.1 to the tune of 900 aircraft. . .far more than the number of planes built by the Hanriot company!
In Belgian and Italian hands the plane performed admirably. Willy Coppens was a top Belgian ace in the HD.1, and the Italians had equipped 16 or 18 squadrons with the HD.1 by 1918. After the war, surplus Italian planes (and 70 more built after the end of hostilities) made their way to several countries, including Switzerland, Paraguay (3 planes) and Ecuador (1 plane). A handful of planes found use with the French and U.S. navies with slight modifications (such as switching their landing gear to floats).
The HD.1 burns 4 gallons of aviation fuel per hour at routine usage. The plane has a historical endurance of 2½ hours and a historical range of 342 miles. A full load of fuel and ammo costs $8.

Subassemblies: Recon Fighter chassis +2; Recon Fighter wings with High-Agility option +2; 2 fixed wheels +0.
Powertrain: 82-kW HP gasoline engine with 82-kW old prop and 15-gallon standard fuel tank (Fire 14) [Body].
Occ.: 1 XCS Body
Cargo: 10 Body

Armor
Body: 2/2C
Wings: 2/2C
Wheels: 2/3

Weaponry:
Aircraft LMG/7.7mm Vickers [Body:F] (500 rounds).

Statistics:
Size: 19'x25'x10' Payload: 0.22 tons Lwt.: 0.67 tons
Volume: 96 Maint.: 137 hours Cost: $2,118

HT: 7. HPs: 30 Body, 35 each Wing, 3 each Wheel.

aSpeed: 114 aAccel: 3 aDecel: 44 aMR: 11 aSR: 1
Stall Speed: 36 mph. Take-Off Run: 144 yards. Landing Run: 130 yards.
gSpeed: 178 gAccel: 9 gDecel: 10 gMR: 0.5 gSR: 1
Ground Pressure: High. 1/6 Off-Road Speed.

Design Notes:
Historical wing area was 194 sf. The design uses High-Agility Recon plane wings as a substitute for Biplane wings, since the SA was a far better match. The weight, HPs and cost of the chassis where doubled to increase design weight; the weight still had to be increased 8% to the historical. The MG load out is a guess. Design aSpeed was 97 mph. Performance calculations were based on historical values for wing area and loaded weight. Fuel capacity was based on the plane's historical endurance and the design fuel consumption.
Design gSpeed reduced by 1/6 for Off-Road conditions is still 82% of the Stall speed; this could allow the aircraft to become airborne even in a bumpy field, at the GM’s discretion.

Variants:
There was provision for a second machine gun to be mounted. Some handful of HD.1s featured a 97-kW engines, and two single prototypes were fitted with 112- and 127-kW engines.
The HD.7 (1918) was equipped with a 224-kW water-cooled engine. It had a top speed of 133 mph. However, the project was dropped with the end of the war.

[johndallman]

Many thanks!