........1.1 This aeroplane is fitted with a Merlin 61 engine and 4 blade (Dural) Rotal hydraulic propeller. The armament consists of 2 x 20 m.m. guns, Hispano Mk.II and 4 x .303" Browning guns. The 8 x .303" Browning gun version has also been considered. Ballast consisting of 5 x 17.5 lb. standard weights is permanently fitted on a bar situated in the fuselage adjacent to the tail wheel.

........1.2 The results of weighing and centre of gravity determination, details of loading, in accordance with preliminary draft of Appendix I to Chap.I, Section 4 of A.P.1565 and centre of gravity form the subject of this report.

2......Weight Summary.

'TARE' Weight (including 5 standard ballast weights of 17.5 lb. in tail57495719
Service load1008798
Fuel 85 gallons @ 7.2 lb./gall.612612
Oil 8.5 gallons @ 9.0 lb./gall. 76 76
Flying weight74457205

*Load 1. 2 x 20 m.m. gun Hispano and 3 x .303 Browning guns.
Load 2. 8 x .303 Browning guns.

3......Maximum Capacity of tanks.

Fuel85 gallons
Oil8.5 gallons

4......Centre of Gravity.

........4.1 The centre of gravity with the above loads measured parallel to the datum line and relative to the datum point (See Fig.1) are: Load 1. 4.4" aft and Load 2. 4.8" aft.

........4.2 The centre of gravity range due to dissipation of load is 4.0" aft to 4.8" aft, Load 2. being on the aft limit. The forward limit is obtained from Load 1. by the expenditure of Browning and Hispano gun ammunition and the consumption of fuel but leaving a supply sufficient for 1.2 hour's running of the engines at maximum power permissible at ground level.

........4.3 A further forward centre of gravity of 1.9" aft may be obtained when the aeroplane is in a light loaded condition of "TARE" weight plus a light pilot of 170 lb. and fuel reduced as in para. 4.2.

........4.4 The moment effect due to undercarriage retraction is 3150 in/lb. and moves the C.G. aft 0.4" at full load.

5......Loading Details.

[FIG. 1 Location of S.M.C. and Datum Point]

[Main] [Spitfire Mk IX]