The Ho III e Motorglider


Usage

 

Motorglider

 

Fuselage Construction

Steel tube

 

Wing Construction

 

Wood

 

Capacity

 

Pilot

 

Motor type

 

Volkswagen engine

 

Power

 

22 kW (29.5 HP)

 

Span

 

20.5 m

 

Sweep Angle

 

24.3 degrees

 

Taper Ratio

 

8.0

 

Wing Root Thickness

 

20% chord

 

Wing Root Depth

 

3.25 m

 

Rib Spacing

 

0.2 m (0.1 m at the leading edge)

Wing Area

 

37.5 m2

 

Aspect Ratio

 

11.1

 

Pilot position

 

Seated

 

Mid-section width

 

2.4 m

 

Cockpit width

 

0.8 m

 

Cockpit height (from seat)

 

0.95 m

 

Empty weight

 

340 kg

 

Ballast (water)

 

---

 

Additional payload

 

80 kg

 

Fuel

 

30 kg

 

Maximum weight

 

450 kg

 

Wing loading

 

12.0 kg/m2

 

Engine loading

20.4 kg/kW

 

Stall speed

 

46 km/h

 

Landing speed

 

46 km/h

 

Minimum Sink

 

0.60 m/s at 53 km/h and 12 kg/m2 loading

Best Glide Ratio

 

28:1 at 70 km/h and 12 kg/m2 loading

Cruise speed

 

120 km/h

 

Maximum speed (horizontal)

140 km/h

 

Maximum speed

 

210 km/h

 
The initial problems with the Mikron engine led us to try a somewhat less powerful "Volkswagen" engine, as this reputable power plant had the added advantage of being air cooled. We also planned to use an automatic folding propeller. The overhead propeller shaft would be driven by five V-belts.

 The power plant was built into an all new center section, while surplus H III b wings were used.

 Heinz Scheidhauer made the first flight in January 1944. Here is his account of a subsequent flight:

 "It is February 22nd, 1944, on a beautiful clear winter morning. It is quite cold; the sun is just rising in the Southeast. In the lee side of the hangar, I can feel the air warming around 10 AM, and soon cumulus clouds are forming over a nearby stone quarry. I observed the clouds for a while with my stop watch, to see how long they remained over the quarry in the stiff NE breeze. It appears that one could soar over there, and soon the Ho III with VW engine and folding propeller is brought to the starting line. At 10:48 I take off. I notice that the cumulus clouds have disappeared, I might just get there when the thermal cycle starts again. I shut down the engine, and glide silently toward the quarry cliff, which I reach at 50 meters above the edge. Here I find a weak windblown thermal, and struggle back up while the strong wind carries me away."

 "Gliding back to the cliff, I find myself below the edge, and begin to circle again. The low altitude does not worry me; I can fly out of the quarry and down the valley at any time, and restart the engine. But now I feel another thermal! I circle tightly at 60 km/in, struggling upward inch by inch. I extract the maximum performance from the Horten, and manage to rise above the cliff again. I am close enough to recognize the faces of the quarry workers, who seem to enjoy watching me. Despite the tight turns at almost ground level, I feel safe in the Horten, knowing that it will not spin under any circumstances. After seemingly endless circling, I catch a stronger thermal, and climb quickly. I wipe my face; that was hard work!

 As the thermals weaken, I again head for the quarry, and arrive at 50 meters again. Another struggle to 250 meters and a glide back. This time I arrive with 100 meters to spare. It is getting better! The next thermal takes me right up to the base of the now beautifully developed cumulus cloud. I turn on the electric Turn and Bank instrument, and continue another 400 meters into the cloud. Here the lift dissipates into just choppy air, and I start the engine and continue climbing. I break out on top at 1400 meters. Now I notice that the engine is running rough, with a strong vibration. I shut it down, thinking that the folding propeller might have failed, and glide back to the airport. The flight lasted over an hour, and after landing, I inspect the propeller. The leading edge of the folded blades are coated with a thick layer of ice! Some has broken off, causing the unbalance."