Author Topic: Spitfire fuel tank and weight (Read 607 times)

F4UDOA · « **on:** September 23, 2003, 10:10:16 AM »

Here is a chart for a Spit IX weighting 7400+LBS.

It shows 85 gallons (Imp) or 102 US Gallons of fuel.

So could someone please tell me where the other 30+ gallons are on the AH Spit? And if they are there why doesn't it reflect in the loaded weight?

1......Introduction.

........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.

*Load 1. 2.
'TARE' Weight (including 5 standard ballast weights of 17.5 lb. in tail 5749 5719
Service load 1008 798
Fuel 85 gallons @ 7.2 lb./gall. 612 612
Oil 8.5 gallons @ 9.0 lb./gall. 76 76
Flying weight 7445 7205

*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.

Fuel 85 gallons
Oil 8.5 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.

Staga · « **Reply #1 on:** September 23, 2003, 10:42:15 AM »

Dunno if this helps.

niklas · « **Reply #2 on:** September 23, 2003, 11:13:27 AM »

do i read "ballast weight"?? Didn´t Col. Carson complain about ballast weight on the 109E?? Lol, he should better have looked at his own fighter.

Nice to have a Spit weight statistic. Thx for the doc F4UDOA.

niklas

F4UDOA · « **Reply #3 on:** September 23, 2003, 12:43:12 PM »

Stega,

It is a two part problem.

The loading chart I have is for 7400lbs with 102 gallons of fuel.

This means that the weight with 102gallons is clearly 7400lbs. So if there is another 30+gallons of fuel on board lets get the weight right and add 200lbs.

The second problem is that even you chart only shows 114 gallons with no mention of imp gallons. And I am looking at source document data and I can't find any reference to anymore than 110 gallons US.