Ho I, Our First Sailplane

Ho I Data Table

Usage
 

Experimenta l

Fuselage Construction

Wood
 

Wing Construction
 

Wood
 

Capacity
 

One person
 

Span
 

12.4 m
 

Sweep Angle
 

23 degrees
 

Taper Ratio
 

6:1
 

Wing Root Thickness
 

20% chord
 

Wing Root Depth
 

3.00 m
 

Rib Spacing
 

0.30 m
 

Aspect Ratio
 

7.3
 

Pilot position
 

Seated
 

Mid-section width
 

4.20 m
 

Cockpit width
 

0.60 m
 

Cockpit height (from seat)
 

0.90 m (0.60m wing thickness,
0.30 m cockpit bubble)

Empty weight
 

120 kg
 

Ballast (water)
 

---
 

Additional payload
 

90 kg
 

Maximum weight
 

210 kg
 

Wing loading
 

10.00 kg/m2
 

Stall speed
 

45 km/h
 

Landing speed
 

60 km/h
 

Minimum Sink
 

0.80 m/s at 60 km/h and 10 kg/m2 loading

Best Glide Ratio
 

21:1 at 72 km/h ant 210 kg/m2 loading

Maximum Speed
 

228 km/h (170 km/h actually flown)
Studies of the stability and controllability of flying wings would continue with our first sailplane. We were hoping to establish the center of lift on each wing half, and also to see if it was possible to steer the aircraft with wing tip drag rudders, instead of the traditional vertical fin-rudder arrangement.

 My brother and I was also hoping to improve our own piloting skills on the H I, as our total flying experience amounted to less than one hour in a primary glider.

 We planned a mean chord of at least one half meter, and a root chord large enough to accommodate the pilot This meant a wing with steep taper. A keel structure contained the seat, 10 cm below the bottom wing surface, and the canopy protruded 30 cm above. The root thickness was 60 cm, which, with a 20 % airfoil thickness resulted in a root chord of three meters.

The resulting triangular wing had an almost straight trailing edge, with two elevators in the center, flanked by two ailerons. The washout was 7 degrees, with most of the twist outside Y= 0.75 (the last quarter of the half span).

 The elevators were moved by pushrods, the ailerons by cables, all attached to a conventional stick. The rudder pedals were linked to drag rudders near the wing tips. They could be operated separately for directional control, or together as spoilers something that had not yet been introduced on other sailplanes. With no workshop available, and no financial support, it was necessary to build the aircraft in our home with personal funds.