The Ho XIV Club Sailplane


Usage

 

Trainer

 

Fuselage Construction

Steel tubing

 

Wing Construction

 

Wood

 

Capacity

 

Pilot

 

Span

 

16 m

 

Sweep Angle

 

18 degrees

 

Taper Ratio

 

5

 

Wing Root Thickness

 

18% chord

 

Wing Root Depth

 

2 m

 

Rib Spacing

 

0.4 m

 

Wing Area

 

15.76 m2

 

Aspect Ratio

 

16.2

 

Pilot position

 

Seated

 

Mid-section width

 

0.8 m

 

Cockpit width

 

0.8 m

 

Cockpit height (from seat)

 

0.5 m

 

Empty weight

 

150 kg

 

Ballast (water)

 

---

 

Additional payload

 

80 kg

 

Maximum weight

 

230 kg

 

Wing loading

 

14.6 kg/m2

 

Stall speed

 

41 km/h

 

Landing speed

 

41 km/h

 

Minimum Sink

 

0.55 m/s at 55 km/h and 14.6 kg/m2 loading

Best Glide Ratio

 

30:1 at 70 km/h and 14.6 kg/m2 loading

Maximum speed

 

250 km/h

 
A Ho IV pilot, practicing short landings, flew through a telephone wire, breaking the front skid and three feet of one wing tip. Since our work shop was fully occupied and the aircraft urgently needed, we simply cut three feet of the other tip as well, and recomputed the lift distribution and center of gravity.

 The Ho IV, serial number 24, now had only 18 meter span, a wider tip, and less washout. Flight tests showed that performance remained about the same, but adverse yaw was now much in evidence. The aircraft remained in the hangar most of the time, as the pilots preferred the 20 meter machines.

To combat the adverse yaw that appeared with the new lift distribution, we considered modifications to the elevons, so they would provide some compensating drag on the up elevon side. This could be accomplished with a "Frise-nose"; recessed hinge points that allow the leading edge of the up elevon to protrude below the wing, and act as an airbrake. During slow flight, this solution creates a dangerous situation, since both elevons will be up, and both leading edges down in the air stream, where they may cause flow separation and control reversal.

 Differential movement, common on conventional aircraft, is also unacceptable, since application results in net up elevator input. This can, however, be avoided by coupling the landing flap into the system, so that they extend slightly during aileron inputs, to make the aircraft nose-heavy. This then, compensates for the up elevator effect. The gap between the up elevon and the down flap will also generate considerable turbulence and drag.

 Our experience with the Ho IV and Ho VI had shown that considerable weight savings could be realized by making the center section smaller, and changing the wing geometry.

 Thus, the concept for a small, light and inexpensive club sailplane was born.

 The last Ho VI was being completed in Aegidienberg while the thunder from the artillery at the approaching front could be heard, so no new project could be started there. It was built in Gottingen instead, using the H IV b building method with molded panels.

 It was covered in April 1945. Alfons Putzer remembers:

 "As Gottingen fell to the advancing American troops, the Horten brothers, myself and a couple of staff members drove to Brandis near Leipzig with a trailer, containing the almost finished Ho XIV. The staff at the Me 163 base there, under the command of Wolfgang Spate, was cooperative, and gave us access to a workshop. As soon as our work got underway, both the Americans and the Russians were practically on our doorstep. The Hortens hurried off to Berlin, while I was asked to try to save the H XIV.

 The three of us remaining put the sailplane back in the trailer again, then managed to commandeer a Mercedes diesel truck, loaded it up with extra fuel cans, hooked up the trailer and headed West.

 Near the front was a large forest with a small village in the middle. Only one road let to it from the East. We decided to hide there, and let the Americans overrun us.

 We hid the sailplane in an attic above a small foundry, where old wooded forms and other junk camouflaged it nicely. Drawings and other documents were put in an metal cylinder, and buried in the ground. Then, there was little to do but settle down in he village inn, which we shared with a refugee lady from Cologne.

 Our first encounter with the Americans did not come out the way we had hoped. One of us, Ing. Warmund, was unfortunately shot, I do not know why! The remaining two of us reached Bonn eight weeks later.

 The lady from Cologne has since informed me that a group of foreign workers were ordered to remove the sailplane from the attic, and destroy it, which they reluctantly did."