The Ho XIII Research Glider for Supersonic Aircraft

Usage
 

Experimental

Fuselage Construction

Steel tubing
 

Wing Construction
 

Wood
 

Capacity
 

Pilot
 

Span
 

12 m
 

Sweep Angle
 

60 degrees
 

Taper Ratio
 

6.5
 

Wing Root Thickness
 

12% chord
 

Wing Root Depth
 

5.2 m
 

Rib Spacing
 

0.4 m
 

Wing Area
 

36.0 m2
 

Aspect Ratio
 

4.0
 

Pilot position
 

Seated
 

Mid-section width
 

2.4 m
 

Cockpit width
 

0.60 m
 

Cockpit height (from seat)
 

1.0 m
 

Empty weight
 

250 kg
 

Ballast (water)
 

---
 

Additional payload
 

80 kg
 

Maximum weight
 

330 kg
 

Wing loading
 

9.2 kg/m2
 

Stall speed
 

44 km/h
 

Landing speed
 

44 km/h
 

Minimum Sink
 

1.1 m/s at 60 km/h and 9.2 kg/m2 loading

Best Glide Ratio
 

16:1 at 80 km/h and 9.2 kg/m2 loading

Maximum speed
 

180 km/h
 
The H XIII a was built in Hersfeld in 1943. It was a glider with 60 degree sweep back, consisting of a pair of Ho III b wings mounted on a special center section. The wing attachments were offset to give the excessive sweep. The span was consequently reduced to only 12 meters. We hoped to gather data on the middle-effect in this configuration, and also explore the handling during slow flight and landing. The pilot sat in a gondola, much like a blimp cabin, mounted under and behind the center section trailing edge. Entry was gained by removing the gondola's tail cone. This made emergency exit and parachute jump easy, since the pilot could simply jettison the cone, which included the seat back, and let himself fall out backwards. A spoiler mounted on top of the center section was nearly useless, because of the middle-effect turbulence there. The L/D was only 12.

 Hermann Strebel did the testing at Hornberg, where it was taken following its maiden flight at Gottingen.

 Here is the initial flight test report: "Weight and c/g was 393 kg, and 4725 mm respectively, wind W. 2 m/s, take off to the NW behind a He 126.

The takeoff was normal, tow speed 130-140 km/h, good aileron and elevator control, weak rudder, adverse yaw light.

 Poor forward visibility, but adequate for the tow. Released at 2700 meters, and flew at speeds between 70 and 150 km/hr, straight ahead. Heavy elevator! Ailerons normal when slow, but at 150, roll control is almost nonexistent. With the stick all the way back, I get 70 km with no stall tendencies. The rudder is still weak, but coordinated turns can be made. A light roll oscillation of about 5 occurs with 45 bank; aileron application will dampen these somewhat.

 The approach is difficult, because the extended skid and the overhanging center section, blocks the view of the runway, making landings in unfamiliar areas very difficult.

 The aircraft touched down fast and bounced a few times, the third bounce resulting in a flat glide with only 50 km indicated. The ineffective spoiler could not prevent the long float over the ground."

 While the research with the H XIII a was linked to the H X delta project, we chose to avoid having the glider identified as part of the project for security reasons. We therefore choose the H XIII a designation instead of HXa. Later the HX was designated H XIII b.

 The H XIII a was destroyed at the end of the war by liberated Russian prisoners.