Nazi Jet-Bats Which Never Took Wing

by Erwin J Bulban,
Editorial Assistant, Aviation
These two- and three-place high-performance twin-jet fighter craft were designed as Hitler hope for regaining air supremacy. Among novel devices planned were use of leading edge flaps and combination ailerons and elevators.
Narrowness of the margin by which the Allies held aerial supremacy over the Nazis at the end of hostilities is only now being appreciated.

Vast amounts of data together with aircraft, engines, and armament have been uncovered by Technical Air Intelligence teams. Many of these new air weapons were ready, or nearly ready, for production in underground factories. And, given the results of their findings thus far, many authorities have expressed the belief that if the war hadn't ended when it did the Nazis soon would have had a good chance of stemming the Allied tide, at least temporarily.

Among the radical aircraft designs discovered are a series of three fighter plane designs on which Gothaer Waggonfabrik (Gotha) had been busily engaged, designated the P-60A, P-60B, and P-60C. The first of these was to be powered by two BMW 003 jet units and would carry a crew of two in prone positions. Takeoff weight was planned at 16,424 lb, wing area at 503.7 sq ft, and top speed was estimated at 593 mph at 4,375 ft. Landing speed would have been about 95 mph.

Slightly larger, but with a similar crew arrangement, the P-60B was to be powered by two Heinkel-Hirth 011 engines. Takeoff weight was to be 22,046 lb, wing area 587.7 sq ft, and top speed was planned at about 625 mph at 3,760 ft. Landing speed was calculated at about 95 mph.

Also powered by two Heinkel 011s, the P-60C was designed as a three-seat night-fighter. Since this craft was to be fitted with a 3'-dia radar scanner, it was necessary to extend the nose and add a cockpit canopy which would have permitted the crew to sit upright.

All three craft were to have retractable tricycle landing gear and pressure cabins. In addition, a Walter-type rocket motor of 4,409 pounds thrust was to have been attached for takeoff and climb.

NACA sections were planned for the wings, with the center section to use 0012.5-0.825-35 airfoils, and with outer root panels of 0012-055-50, and tip sections of 0010-1.1-30. Maximum thickness was to be 40% at the tips, but it is reported that this point was later moved forward to 30%. Taper ratio was to be 0.36. A symmetrical profile was decided upon because of its high speed characteristics, especially in view of moment, and with consideration for ease of construction. The Ge mans believed that a sharp nose would give higher critical Mach numbers, especially at high lift coefficients. For improvement of control surface characteristics, maximum thickness was distributed from 50% chord at root section to 30% at the tips. Dihedral was to be 1°.

A novel feature of the craft's wing was to be use of leading edge flaps which could extend about 135° from the airfoil centerline. These flaps were designed to increase the radius of curvature of the nose in addition to increasing camber, thus to slow the separation of flow on the upper airfoil surfaces. It is stated that these flaps would allow favorable stalling characteristics at the stalling point. Another advantage: There would be no modification in either trim or slope of the moment curve at the high lift range.

An interesting mechanism which would have been utilized to take care of aileron control forces in case low speed lateral stability proved unsatisfactory was an automatic device to artificially produce lateral stability. Using a yaw vane indicator, it would be in the form of an aileron actuator to cause a rolling movement in the desired direction.

No vertical tail surfaces were to be fitted to either the P-60A or B, since it was believed that the cleanness of these designs, together with the vertical fin effect of the engines, would give satisfactory directional stability.

However, it was decided that the enlarged nose section and cockpit canopy on the P-60C would cause turbulence, therefore vertical fins and rudders were designed to be fitted on the wings between the control surfaces. These were to be set in from the tips so that the fins could be used to straighten out the cross-flow on the rear section of the swept-back wings. This location would also have less effect on damping roll and so allow greater rolling speeds.

Control surfaces would consist of elevons (combination elevators and ailerons), which were to be divided into two sets, inboard and outboard. The outer set was intended for use at only high speeds, though both sets could be used at low speeds. The outer elevons were to be linked directly to the pilot's controls, but the inner set would be actuated by a servo-tab with force exerted on the tab only. Thus, the inner elevons would be allowed to float freely.

Outboard elevons were planned as blunt-nosed Frise-type for best possible effectiveness, hinge moments, and drag characteristics. Aerodynamic nose balance was temporarily set at 26% for the outboard set and 28% for the inboard. Less balance was desired for the outer, since this set would yield the primary portion of the pilot's action, hence the more linear control feel characteristics were sought. The inner elevon would have a Flettner tab which could also be used for longitudinal and lateral trimming.

Rearward, exposed placement of the power plants was decided upon so that engine heat would be kept away from the wing; critical Mach number would be increased by placing the engines to the rear; drag would be lower than that of buried engines, since leading edge ducts would disturb the flow over that portion of the wing; and external mounting would favor maintenance. Cockpit layout of the P-60C was to have been of conventional design. However, the P-60A and B were to have hanging rudder pedals and stick, plus a control to separate the tab control mechanism from the stick. It was believed that no pilot discomfort would be experienced using prone positions in flights of up to 3 hr duration. This had been tested by DVL, the German research laboratories, in a plane especially built for this purpose. For longer periods it was considered desirable that two pilots be used. It was stated that lack of rearward vision would be compensated by the P-60's high speed.

From the evidence gathered it appears that no full scale aircraft of any of these types was ever built and flown. The P-60C design was entered in a German night-fighter competition against seven other craft (including two tailless types) entered by Arado, Blohm & Voss, Dornier, and Focke-Wulf.

Previously, Gotha had been working on the Horten Brothers 229, also a flying wing. Horten had obtained this contract by going directly to the German Air Ministry. However, since the firm did not have sufficient production facilities, the Ministry ordered Gotha to proceed with the design. Gotha built the 229 V-4 (V means versuchs, or experimental), also a center section for the V-5, as well as starting construction of the V-6 and making detailed plans for the V-7 and V-8. Little data is as yet available on these craft. The only 229 to be flown crashed on its second flight.

This article was originally published in the October, 1945, issue of Aviation magazine, vol 44, no 10, pp 172-173.
The original article includes 3 captioned drawings.
Rendered drawing by the author.

Drawing captions: