Horten Ho VIII
Reimar Horten says in his biography:
Our next project was a large aircraft with 120 feet span and six engines. This Ho VIII would have two fuselage pod configurations one for cargo, the other build as a flying wind tunnel. Unfortunately, no contract was received to build it.
However, the construction progressed quickly through the spring of 1945, and the aircraft was half finished when the American forces reached Goettingen.
In February 1945 a committee under Professor Bock with representatives from Junkers, Messerschmitt and Horten, deliberated over the optimum design for a 4-jet-engined bomber. Designs by Junkers (Ju 287. A swept forward tailed aircraft), Messerschmitt (Project 1107 as swept back tailed aircraft), and Horten (swept back tailless) were considered, and a joint report issued giving the committee's opinion on the best estimate for relative performance. Junkers published the report.
I was invited to attend a high level meeting with Goering, where the prospect of a long range bomber was discussed. The official demand was: 4000 kg bombs, and 4000 mile range. The Junkers 287 was to be compared with other proposals. Messerschmitt submitted one, we another. Six Jumo 004 jet engines were suggested as powerplants for all.
After three days of discussions, it became clear that our flying wing would have far better range than the others, although short of the required 4000 miles. Thus it appeared that an order for a large bomber would come our way, so we decided to build an intermediate size aircraft to gain experience.
To minimize the risk of aerodynamic surprises, we simply doubled the dimensions of the trusty Ho III. This improved the calculated L/D to 30, since the friction drag coefficient was reduced through a fivefold increase in the Re numbers.
All our calculations needed verification in a wind tunnel. As they remained unavailable, we decided to help ourselves, and put a tube shaped fuselage in the Ho VIII, to make it a flying wind tunnel.
The Argus engine used in the Ho VII would be used, with six units mounted in the wings driving pusher propellers. The wing would have a box spar, with all control rods and cables inside the spar, to free the remaining wing space for fuel tanks.
The construction progressed quickly through the spring of 1945, and the aircraft was half finished when the American forces reached Gottingen.
The specification to be noted was for 900 km/h at 10 km height and a range of 3,000 km using four H 11 jets. According to Horten the committee decided that his machine, given the same top speed as the others would have more range and less landing speed. (125 km/h against the 175 km/h for the others.) Alternatively he could carry 8 tons of bombs against the 4 by his competitors for the same range.
The dimensions of the aircraft were roughly as follows:
| Ju and Me: | Horten VIII: | |
|---|---|---|
|
Span: |
17-18 m | 30 m |
|
Aspect Ratio: |
5.5 | 5.5 |
|
Wing pressure: |
500-600 kg/sq.in. | 220 kg/sq.in. |
All the above figures were remembered by Reimar Horten, who used them as a rough illustration. They are not necessarily accurate.
In the structural design Reimar Horten reckoned to save 6% of the all up weight (spar and rib weight) compared with the conventional type. He thought the committee a bit unfair because they insisted on increasing his estimate of structure weight by about a ton.
Specifications
| Usage | Experimental |
| Fuselage Construction | Steel Tube |
| Wing Construction | Wood |
| Capacity | Three people |
| Motor type | Six Argus As 10 engines |
| Power | 6 x 176 kW (6 x 236 HP) |
| Span | 40.0 m |
| Sweep Angle | 33.7 degrees |
| Taper Ratio | 8.1 |
| Wing Root Thickness | 18% chord |
| Wing Root Depth | 6.5 m |
| Rib Spacing | 0.4 m |
| Wing Area | 146.0 m2 |
| Aspect Ratio | 11.0 |
| Pilot position | Seated |
| Mid-section width | 4.0 m |
| Cockpit width | 0.80 m |
| Cockpit height (from seat) | 1.1 m |
| Empty weight | 5000 kg |
| Ballast | water |
| Additional payload | 240 kg |
| Fuel | 2760 kg |
| Maximum weight | 82000 kg |
| Wing loading | 55 kg/m2 |
| Engine loading | (5.55) 7.6 kg/kW |
| Stall speed | 80 km/h |
| Landing speed | 80 km/h |
| Cruise speed | 250 km/h |
| Maximum speed (horizontal) | 280 km/h |
| Maximum speed | 430 km/h |