In Germany Reimar Horten assisted by his brother Walter built a series of swept-wing sailplanes without conventional fuselages or tails. Almost seamlessly blending the cockpit into the centersection, the brothers successfully flew their aircraft without
fins, rudders, stabilizers, or other vertical surfaces usually employed for control or
stability.
In order to retain their finless wing layout and get the maximum aerodynamic
efficiency, the pilot was put in a prone position with his body in a 27% thickness
ratio egg and his knees and legs in a small leg well, which also supported the rear
skid .
The "praying mantis" pilot position proved to be very comfortable on long flights.
The pilot could rest his chin on a soft cushion, the safety harness was buckled on his
back, but could be released along with the cockpit cover in an emergency.
The first Ho IV flew in May 1941 at the Konigsberg luftwaffe base. After a few low
level winch tows, the test pilot Scheidhauer took an aero tow to 10000 feet and returned after more than one hour in the air.
Two survived the war, and were flown by RAF personnel in Germany and England until 1950.
Serial no26 remained in Germany and was put into storage after a crash landing. When it became part of the Deutsches Museum collection in 1971, the mid-section was missing and was reconstructed during restoration work.
Serial no25, was transported to England, and went through several owners, ending up in the USA in 1951. The following year, Rudolf Opitz won two major soaring contests with it, and placed seventh in the Nationals, after losing points through a navigational error.
In 1959 it was chosen by the Aerophysics Department of Mississippi State University to take part in a sailplane research program
The aircraft is now on display at the Planes of Fame museum in Chino, California
The Cockpit
A Spoiler lever
B Combined cockpit cover and seatbelt release
C Tow release
D Control handle and boot heating switch
E Battery on/off
F Charging socket for accumulator
G Heated control grip
H Front skid deploying lever
I Oxygen system
J Chin and arm rests
K Trim lever
? The inventory taken of the aircraft at Farnborough in 1945 shows two variometers so that is what I have shown , however the actual gauge is a mystery , If you recognise it please let me know!
Specifications
Span 20.3 m
Sweep Angle 20 degrees
Taper Ratio 6.0
Wing Root Thickness 16% chord
Wing Root Depth 1.55 m
Rib Spacing 0.20 m (0.10 at the leading edge)
Wing Area 18.9 m2
Aspect Ratio 21.8
Pilot position Prone
Mid-section width 1.6 m
Cockpit width 0.8 m
Cockpit height 0.55 m
Empty weight 250 kg
Ballast (water) ---
Additional payload 80 kg
Maximum weight 330 kg
Wing loading 17.5 kg/m2
Stall speed 55 km/h
Landing speed 55 km/h
Minimum Sink 0.50 m/s at 60 km/h and 17.5 kg/m2 loading
Best Glide Ratio 37:1 at 73 km/h and 17.5 kg/m2 loading
Maximum speed 200 km/h
