Recent Flying Limitations Imposed on German Aircraft, WWII Tactical and Technical Trends, No. 23: April 22, 1943 (Lone Sentry)

An indication of possible reckless or unintelligent flying on the part of GAF pilots may be found in recent instructions, establishing certain restrictions on the operation of various airplanes, issued by the Germany Air Ministry. This was done to reduce the loss of, or damage to, particular planes by overtaxing their capabilities. The particular types covered are the FW-190, the Me series, the He-177, and the Ju-88.

The maximum permissible operating speed for the FW-190 have been reduced from 466 mph at all heights to the following:

Up to 10,000 ft - 466 mph

From 10,000 ft to 16,500 ft - 428 mph

From 16,500 ft to 26,250 ft - 360 mph

These speeds are to be marked on the air speed indicators in each aircraft and are only permissible with strengthened elevators. Aileron corrections at high speeds must remain within moderate limits.

The He-177 combines light elevator control with good elevator effect, but has a comparatively low factor of safety, with the result that wrinkling of the skin on the wings or wing failures may occur from careless flying. Permissible pull-out acceleration at the present time amounts to 2.3g with a flying weight of 27 tons, and crews are reminded that high stresses may be caused when pulling out of a glide at high speed, by sharply pulling up out of horizontal flight at any speed, and in steep turns or by strong vertical gusts at high speed. A warning is issued that the automatic pull-out apparatus can unintentionally cause a strain of over 2.5g by tail-heavy trimming before the release of the bombs, by pulling back on the control column at the time of the automatic pull-out if the centre of gravity lies too far to the rear, or when dive-bombing is done in very gusty air. In the latter case, speed should be reduced to 186 mph. The pilot must be trained to watch closely the air speed indicator and the acceleration warning apparatus during every pull-out.

In the case of all aircraft of the Me-109 series, including the Me-109G, attention is called to the numerous accidents caused by wing breakages, resulting from strains induced by air speeds in excess of the permissible maximum limits. All previous limitations are therefore cancelled and the following are substituted (previous limits are given for comparison):

    Limit     Previous Limit

Up to 10,000 ft 466 mph   466 mph

At 16,500 ft   435 mph   425 mph

At 23,000 ft   357 mph   382 mph

At 30,000 ft   280 mph   341 mph

At 38,000 ft   248 mph   304 mph

A corresponding notice is to be placed on all airspeed indicators in these aircraft.

Warning is also given against yawing in a dive, which under certain conditions leads to high, one-sided wing stresses which the wing tips cannot support. When yawing occurs, the dive is to be broken off gradually, without exercising force. Wing tips must be examined and checked frequently for signs of failures. When yawing is encountered during turning, correction must be made with the rudder only and not with the ailerons. Mention is also made of high-wing stresses caused by the unintentional unlocking of the landing gear especially the dropping of one side in a dive. It is stated that steps are being taken to prevent this.

Apparently, even the yellow recognition paint on the ailerons changes their characteristics unfavorably and paint already put on is to be removed.

Reference is made to the difficulty of controlling Ju-88 aircraft at a dive angle of 60°, and it is stated that in the future they are to be rigged for a dive angle of 50° only. This will limit the indicated air speed in the dive to between 329 and 341 mph as against 341 to 354 mph obtained in a 60° dive.