Building the Supermarine Spitfire
Section 1
Supercharged V6 Isuzu 3.5
Fuel 98 to 100 Octane
Oil 15w 40
4500-4800 rpm
Oil pressure 60-80 psi
Cruise 3200 rpm
Fuel pressure 42-52 psi
Flying Limitations
Vmo 193 kts
Vle 110 kts
Vfe 90 kts
U/C Levers – both forward
U/C Electrical Switches – both down
Flaps – Up
Fuel - Sufficient for Flight
Fuel Cock Lever – ON
Throttle – CLOSED
Propellor - FULL FINE
Radiator Shutter – OPEN
Brakes – ON
Master Switch - ON
Ignition Switch - ON
Allow engine to warm up at 1000-2000 rpm until water temperature reaches 80 deg C. and oil temperature 50° C.
Engine Instruments - CHECK
Flight Instruments - CHECK
Ignition Systems - CHECK
Fuel - ON & SUFFICIENT
Pitch - FULL FINE
Trim - SET FOR T/O
Flaps - UP
Controls - FULL & FREE
DATUMS
For weighing and weight and balance references:
Horizontal Datum: Topside fuselage longeron
Vertical Datum: Front face of the firewall
CENTRE OF GRAVITY RANGE
Using the front face of the firewall as vertical datum and the top, side, fuselage longeron as horizontal datum, the centre of gravity range, in % of MAC is set at: Forward limit: 18% (520 mm aft of datum) Rear limit: 34%. (745 mm aft of datum) This centre of gravity range to be verified by flight test including spin / spin recovery trials and applies to all gross weights up to 810 kg.
ITEM ARMS
For weight and balance purposes these arms from the vertical datum, front face of the firewall apply:
Pilot: + 1100 mm
Fuel: + 400 mm
Oil : - 600 mm
Baggage: + 1600 mm
Passenger: + 1600 mm
Propeller: - 1260 mm
Spinner/Plate:- 1375 mm
Rear fuselage ballast: +4900 mm
Weighing to be with unusable fuel only, full ail, full engine coolant ,no baggage.
Where X = Distance of Centre of Gravity Aft of Firewall
Where W1 = Weight measured at Mainwheels
Where W2 = Weight measured at Tailwheel
Where A = Distance from Firewall to Mainwheels
Where B = Distance from Mainwheels to Tailwheel
Where W = Empty Weight
Design Gross Weight 810 kg
Typical Empty Weight: 551kg
Weight of Non Flying Parts:
Pilot: 110kg
Engine, mount, controls cowls etc: 245 kg
Propeller/Spinner:20kg
Fuselage complete:114kg
Tailplane:18kg
Fuel ( Part of 115L):84kg
Baggage 2nd pilot:75
NFP TOTAL:666kg
Wing Weight:
Outer panels (2):64kg
Centre section:56kg
Undercarriage assemblies (2):24kg
TOTAL WING WEIGHT:144kg GROSS WEIGHT:810kg
Design Gross Weight 720kg
Typical Empty Weight: 551kg
Weight of Non Flying Parts: Pilot 86kg
Engine, mount, controls 245kg
Propeller Spinner 20kg
Fuselage complete 114kg
Tailplane 18kg Fuel ( Part of 115L) 93kg
NFP TOTAL 576 kg
Wing Weight: Outer panels (2) 64kg
Centre section 56kg
Undercarriage assemblies (2) 24kg
TOTAL WING WEIGHT 144kg
GROSS WEIGHT 720kg
Using set criteria the following loading combinations must be contained inside the nominated, in-flight, Centre of Gravity limits. For dual flight the rear passenger allowance is to be calculated and then placarded.
Foward CG Limit Case Maximum fuel 84 kg
Minimum weight pilot 55 kg
Forward CG Limit set at: 18% MAC
Rear CG Limit Case: Only unusable fuel
Maximum pilot 110 kg
Passenger calculated
Rear C.G limit set at: 34% MAC
To bring the tailwheel weight ,when weighed empty in the level attitude, to between 2kg and 4kg, up to 6 kg of ballast may need to be added to the fin ballast point.
The following definitions apply to warnings, cautions and notes used in the flight manual.
WARNING: means that the non-observation of the corresponding procedure leads to an immediate or important degradation of the flight safety
CAUTION: means that the non-observation of the corresponding procedure leads to a minor or to a more or less long term degradation of the flight safety
NOTE: draws the attention to any special item not directly related to safety but which is important or unusual.
Wing span: 27.5Ft
Wing Area : 122 SqFt
Mean Aerodynamic Chord: 1380mm
Wing Aspect Ratio: 6:1
Span fixed centre section: 7.8Ft
Span of each outer panel: 9.85Ft
Dihedral: 5 Deg
Design gross weight: 810kg
Engine : Isuzu V6 Supercharged
Horse power: 330hp
Propeller: Variable pitch propellers meeting engine makers requirements and the airframe weight and balance limits are allowed
Diameter pitch: 78 in
Aileron up travel: 14 deg
Aileron down travel: 12 deg
Elevator up travel : 18 deg
Elevator down travel: 15 deg
Rudder travel each way: 30 deg
Landing flap down travel: 70 deg
Main Fuel tank capacity: 115 litres
Wing Tank capacity: 85 litres each
Wing incidence to datum: +2.0 deg
Wing outer panel washout: -2.5 deg
Horizontal tailplane incidence: 0 deg
Flap system: Electric
Retracting U/C System: Electric
Steel tube U/C legs: Rubber/Spring in Compression
Hydraulic wheel brakes: Disc
12 volt electrical system: 30 amp
Elevator trim: Push/Pull
Main wheels: 15-600-6
Main tyre pressure: 35 psi
CONSTRUCTION OUTLINE
The Spitfire MK 26 is of all metal construction, pressed ribs and frames, with alloy tube section main spar caps. A mixture of aircraft grade and commercial grade materials are used: The wing main spar utilises 6061-T6 square alloy tubing for the top and bottom caps and 2024-T3 alclad sheet alloy for shear webs. The aircraft is skinned in 2024-T3 alclad sheet alloy All frames and ribs are formed from 2024-T3 alclad sheet alloy The undercarriage legs are 31 6 stainless steel tube and 41 30n steel parts The engine mount is 4130n round tube of varying dia and wall thickness The structure is rivetted using mainly blind rivets. Engine cowls are constructed in Fire Resistant epoxy resin/glass cloth. Normal aviation construction conventions are applied throughout the structure, flight and engine control systems.
For reference purposes, throughout this document, the relevant parts of FAR Part 23 references and guidelines will be shown " (23-*)"
" The relevant parts of JAR-VLA will be shown "(VIA***)"
CATEGORIES
(A) UTILITY
The Mk26 when loaded to 810 kg will carry one pilot, one passenger and a significant fuel load. In this condition FAR 23 "Utility Category" limitations apply.
(B) AEROBATIC
The basis of VLA Aerobatic Category justification. The Mk26 when kept to solo only (no passenger) will operate at a gross weight of 720 kg which would be the basis of Aerobatic Category justification.
This Type Report does not specifically address Aerobatic Category for the Mk26 but does provide some basic specifications for later use and shows where structural tests have gone to this level.
DESIGN LOAD FACTORS
Design load factors are determined from VLA Appendix A table 3 observing the basic factors set out in VLA 337 and FAR A23 .
UTILITY AEROBATIC
Limit positive load factor Va NI +4.4
Limit negative load factor Va N2 -2.2
Ultimate positive load factor +6.6
Ultimate negative load factor -3.3
Limit positive load factor VC N3 +4.4
Limit negative load fador VC N4 -2.2
General safety factor 1.5
Other safety factors are applied to specific parts of the structure and systems as recommended in FAR 23 I JAR guidelines.
PILOT WEIGHTS
JAR and FAR differ in their requirements for body weight. Since body weight is a significant part of a small aircraft and can seriously affect the balance. The more conservative line of JAR 22 which asks for a solo pilot with parachute to be a maximum of 110 kg and a minimum of 55 kg and 2 pilots combined to not exceed 200kg has been adopted. This directly influences such things a seat design, harness restraint, maximum weight of non flying parts, Centre of Gravity range etc. The reality is that in 2006, body weights are on the increase which is accounted for in the JAR 22 requirements.
Pilot weights include parachute if worn. This aircraft is to be weighed and these weights shown by cockpit placard for each category.
OPERATING SPEED LIMITS - VIA (knots E.A.S)
With a calibrated pitot/static head under the LH wing tip, Position Error is negligible in the working speed range. All speeds to be confirmed by flight test.
FLIGHT CONDITION
Stall Speed (flap U/C retracted) Vs1
Stall Speed (flap and U/C extended) Vso
* Max Speed Flap extended VFe
* Design Manoeuvre Speed Va
* Design Speed for Maximum gusts Vb
* Maximum Structural Cruise Speed Vno
*Maximum Operating Limit Speed Vmo
* Maximum U/C extend Speed Vlo
* Maximum Speed U/C extended Vle
SPEED KTS EAS
UTILTY AEROBATIC
* These speeds can be assumed to be I.A.S. and are to be placarded in the cockpit and used for A.S.I. colour coding.
The following speeds are determined for various aspects of flight test work taken at Gross Weight 810kg, Utility Category. These speeds for design and test flight are considered to be CAS and subject to both Instrument Calibration Error and Position Error for conversion to IAS.
Stall speed Flaps & U/C extended:Vso = 43kts
1.2 Vso = 54kts
1.3 Vso = 59kts
1.4 Vso = 61kts
Stall speed clean:Vs = 52kts
1.2 Vs = 65kts
1.3 Vs = 71kts
1.4 Vs = 76kts
Demonstrated Cruise speed @ SL: Vh = 160kt
Design Cruise Speed:Vc = 136kts
Design Dive Speed: Vdmin 215kts
Placarded maximum Vmo:(.9*Vdmin) 190kts