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Jan Straka: Sopwith F.1 Camel

Sopwith F.1 Camel was developed as replacement of Sopwith Pup. The prototype first flew in December 1916. It was equipped with two synchronized machineguns Vickers 7.7mm. The plane was called Camel due to typical hump covering guns breech. The first planes were given to operation units in May 1917 and in July the fighting started. There were about 5500 Camels produced during the war. On contrary to previous Sopwith Pup and Triplane the Camel was not considered easy to fly plane. Gyroscopic and reaction momentum of rotary engine made the plane rather dangerous during take off and landing in hands of unskillful pilots. Camel was very sensitive and required focus during whole flight. On the other hand the experienced pilots could use those properties and fast left turn of Camel became famous. During summer of 1918 the Camel started to be obsolete as a fighter. It was used more often for land attacks. Further it was replaced by modern Sopwith 7F.1 Snipe. More information can be found e.g. on Wikipedia.

I built the Camel based on linedrawing in the book Vojenská letadla 1. Letadla první světové války, Václav Němeček, published by Naše vojsko in 1974 and I also used monography in Modelář magazine, 12/1973. I also used Internet sources on favourite server Unfortunatelly just after finishing the building I found nice plan on the the plan page.

Used equipment is shown in the table:

Receiver: MINOR 35
2x servo: RC-1
Battery: LiPol130-P
Motor: G15 4W Bee
Propeller: MCF5030S 128 mm
Controller: MBC3

The model is built in 1/20 scale. Unfortunately I can not reconcile at this type of plane with the idea of having dihedral on the upper wing. It was clear that there will be trouble with lateral stability in combination with no ailerons which are hard to make in such model size. The skeleton is made from balsa using classical methods. After covering the wings and front part of the fuselage I used templates to get proper dihedral on lower wings, incidence angles and parallel wings. The back part of the fuselage was covered after installation, adjustment and tests of servos which control the rudder and elevator. Keeping resistances minimal is necessary. I used thin strips of transparent adhesive tape as hinges. As the front part of the Camel is quite short, I had to put all equipment into the front. Battery is placed in box covered under engine cowl, the box also serves as motor mount. The finish was made after the trimming flights (Agama colors).

Final flight weight is 45 g with wingspan of 425 mm. This combination is on the edge of the drive, however the Camel is capable of fast flights. It took me a while to trim the plane into smooth flight. The COG is pretty high (I think due to the no dihedral on the upper wing). The left turn is perfect, plane is capable to return to direct flight without touching the controls. The right turn is a puzzle. It must be flown very carefully as it puts the plane into unstable state. If the turn is too sharp there is nothing one can do using only rudder and elevator. The only solution is to shut off the engine.

Thanks to my irresponsibility during one low pass I hit the plant reminding orache, which was exceeding other meadow plants. The pilot was catapulted from the cockpit and lost. Bitterness from the loss was huge in spite the fact that flying characteristics improved. So the next day I made new pilot, even nicer one. However, if somebody accidentally finds the pilot, please return him to me.

Finally I would like to thank Ing. Štefan Gašparín and Ing. Ivan Motička for their willingness and help. The photos in the gallery were made by Lucka.

[Jan Straka]