North American Sabre Mk.4 sabrepic051

PART III - HANDLING (vi)Changes of trim Undercarriage down Weak nose-up initially and finally weak nose-down Undercarriage up Slightly stronger nose-up Flaps down Slight nose-down Flaps up Slight nose-up Air brakes out Strong nose-up at high speed decreasing to mild at low speed Air brakes in Strong nose-down at high speed decreasing to mild at low speed (iii)Flying at reduced airspeed Fly at 150-160 knots with the air brakes out and the flaps fully down. At low altitudes about 80 per cent. r.p.m. will be necessary to maintain level flight. 59. Maximum range and endurance (i) When maximum range is essential the climb should be made at 100 per cent. r.p.m. and cruise carried out at the best height for the required range, as indicated on the Flight Planning Charts in Part VI. (ii) At any altitude, maximum endurance is obtained by fly- ing at the I.A.S. which requires the lowest r.p.m. to main- tain height. This speed is approximately 195 kts. on a clean aircraft or with 100 gall. drop tanks, and 200-220 kts. with 167 gall. drop tanks. Increase in altitude up to 30,000 ft. gives a slight improvement in endurance, especially at the low weights, but the amount of fuel required to reach a higher altitude must be considered. 60. Pressure error corrections The pressure error corrections are negligible. True air- speed may be calculated direct from indicated airspeed by use of the Mk. IV computer. 61. Flying with the hood open (i) The maximum speed at which the hood can be opened and at which continuous flight is permitted is 215 knots. Considerable draught is experienced at the maximum speed and loose articles and the shoulder harness tension- ing straps should be secured before opening the hood. (ii) If a landing is made with the hood open it is recom- mended that it be opened only halfway. In this position there is less draught, while the forward view is practically the same as with the hood fully back.