Humber 15

Humber 15.9
3-door saloon registered January 1924
Overview
Manufacturer	Humber Limited
Production	1919–1928[1]
Body and chassis
Body style	5-seater open tourer (AllWeather) 3-door saloon (spare is by driver) saloon landaulette chassis only also available[1]
Layout	FR[1]
Powertrain
Engine	2815 cc Straight-4[2]
Transmission	enclosed Ferodo-lined clutch, a short Hardy disc-jointed shaft to the four-speed gearbox which is held at four points with its control by driver's right hand, open propellor shaft with one fabric (front) and one metal universal joint to bevel driven rear axle[3]
Dimensions
Wheelbase	123.5 in (3,137 mm) Track 57 in (1,448 mm)[3]
Length	173 in (4,394 mm)[4]
Width	69 in (1,753 mm)[4]
Kerb weight	Saloon 31 cwt, 3,472 lb (1,575 kg)[4]
Chronology
Predecessor	Humber 20
Successor	Humber 15/40

Humber 15.9 engine
Combustion chamber
Configuration	Straight 4-cylinder[1]
Displacement	2,815 cc (171.8 cu in)[2]
Cylinder bore	80 mm (3.15 in)[1]
Piston stroke	140 mm (5.51 in)[1]
Cylinder block alloy	cast-iron monobloc suspended at four points[2]
Cylinder head alloy	cast-iron detachable[3]
Valvetrain	overhead inlet, side-by-side exhaust; tappets, pushrods and rockers; force-feed lubrication; timing by chain[3]
Combustion
Fuel system	Cox Atmos carburettor with air-intake muffler and strangler control on instrument panel; fuel delivered by vacuum and gravity[3]
Management	magneto and CAV generator[3]
Fuel type	petrol[3]
Oil system	splash and gravity feed from a reservoir filled by gears from sump, there is a dipper gauge[2]
Cooling system	radiator, fan and linked water impeller for circulation[2][3]
Output
Power output	40 bhp (30 kW; 41 PS) @not provided rpm[1] elsewhere 33 bhp @2000 rpm Tax horsepower 15.9[1]
Chronology
Predecessor	Humber 20
Successor	Humber 15/40

Humber Fifteen 15 horsepower cars were medium to large cars, classified as medium weight, with a less powerful than usual engine which attracted less annual taxation and provided more stately progress. The coachwork was superbly finished, specially the tourers,^[5] and these cars were much favoured by the professional classes.

They were manufactured from 1919 to 1924 and 1924 to 1927. Their former place in Humber's catalogue was bracketed in 1927 and 1928 by new cars, a much smaller engined 14/40 or late in the same year a 20-horsepower six-cylinder 20/55 of ten per cent greater capacity.

Introduction

These cars were displayed at Olympia's first postwar Motor Show in November 1919. Commentators described the design as common-sense and not sensational with evident attention to detail. The blue saloon with shining black roof and mouldings drew attention.^[1]

Fifteen .9

Engine

The 2.8 Litre four cylinders in line engine made in a single casting has a detachable cylinder head and is fitted with, new for Humber, overhead inlet, side-by-side exhaust valves.^[3] Their equivalent prewar car with an engine of 3.3 Litres had twin overhead camshafts.^[4]

Bodies

The 15.9 is available as a saloon or a 5-seater tourer. There is no door for the driver because the brake lever and gear change lever are to his right and the spare wheel and tyre are fastened to the outside of the car at the same point.

A special pull control for the CAV starter is mounted on the dashboard.[2] The steering wheel carries an advance and retard (timing) lever and an ignition switch.[3] Steering column rake is adjustable[3] The split windscreen reaches down to the curved dash without a wooden fillet.[2] Its instrument panel includes a cupboard and two drawers and a Jaeger speedometer run from the gearbox. There is also a clock and an air control. There are scuttle ventilators.[2] Beneath the bonnet there is storage for the wheelbrace, jack, oil-can etc., small tools are in the passenger's side front door and there is a further locker below the front floorboards[3] The tourer has some special features. Humber claims this open tourer converts to an All-Weather car in a few seconds. The aluminium-framed celluloid side curtains, carried neatly below the driver's seat, can stay up when the hood is lowered. For the back seat passengers there is a combined rear cowl and screens.[6] The cowl covers passengers' knees and two single windscreens by Auster carried inside the cowl, when needed, are mounted in slots on the cowl and secured by butterfly nuts. The cowl itself is quickly released when the all-weather configuration is wanted.[2] Later cars were given a single large Auster windscreen with hinged wings at each side to give passengers further wind-protection.

A saloon landaulette was added to the standard range and it also shows the care and forethought put in to give comfort and convenience. Between front and back seats it has a glass partition with sliding panels and there is an extra fold-away seat in the rear compartment which may be turned to face either side.^[7]

Brakes suspension steering

The hand lever to the driver's right by the change-speed lever operates internal expanding brakes on the back wheels, the foot brake pedal operates a contracting band on a drum just behind the gearbox. A hand adjustment for wear is provided for both rear and transmission brakes.^[2] The Times thought the suspension was not quite free from fore and aft movement but was otherwise satisfactory and comfortable on a rough road. The springs are set with a minimum of camber,^[2] they are half-elliptical, set on top of the axles and from 1923 Hartford shock absorbers were fitted at the back.^[3] Steering is by worm and complete wheel and can be adjusted for wear^[3]

Test

A road test of Humber's Fifteen horsepower five-seater open tourer by the motoring correspondent of The Times resulted in published comments along the following lines. The Fifteen is an expensive car but, without an employee for the purpose, an owner who drives it himself is expected to care for its every need, daily.^[2]

The owner-driver's needs seem to have been considered very carefully and all but one of them met, that is the difficulty in draining engine oil which requires the removal of an undershield. A minor point was that the rear tappet plate was made difficult to remove by having carburettor control springs anchored on it. A few drops of oil two or three times a week and tappets will run for a long time without shake otherwise they soon become noisy.^[2]

The following good points were noted by The Times:

easy to reach magneto, dynamo, starter and carburettor

clutch spigot and the withdrawal mechanism automatically lubricated

all brakes have easy to reach hand adjustments

no grease-cups but spring-controlled ball-valve greasers throughout the chassis, special gun supplied

easy to reach tools, access does not disturb a passenger

fuel tank at the back has a gauge easy to read when the luggage grid is fully loaded

fuel tank fuel filter funnel

all-weather hood; the side-curtain beside the driver has access for a signalling arm^[2]

Accordingly, The Times also noted that "it is not necessary to lift floorboards and poke about with an oilcan before a journey".^[2]

The car is moderately fast, best run 50 miles per hour (80 km/h) but it seemed to have a minor fault and should have reached 55 miles per hour (89 km/h).^[2] Seating is comfortable with unusually generous knee room in the front seat. Of 5-seater owner-driver cars that have been submitted to The Times for trial this car, said the reviewer, is the best.^[2] He did consider the car a little narrow for five passengers but decided there is sufficient legroom^[3]

On the road, he reports, the lively quiet and flexible engine is silky on top and accelerates with real spirit. Though the clutch can grab, the gears are easy and quiet. The car's steering is delightful but its brakes and suspension are only satisfactory.^[2]

Fifteen 40

Humber 15/40
saloon registered December 1927 Humber Mole with black trimmings
Overview
Manufacturer	Humber Limited
Production	1924–1928[8]
Body and chassis
Body style	5-seater open tourer (AllWeather) 4-door saloon saloon landaulette with 2 occasional seats chassis only also available[9]
Layout	FR[8]
Powertrain
Engine	2815 cc Straight-4[8]
Dimensions
Wheelbase	123.5 in (3,137 mm) Track 57 in (1,448 mm)[8]
Length	173 in (4,394 mm)[4]
Width	69 in (1,753 mm)[4]
Kerb weight	Saloon 31 cwt, 3,472 lb (1,575 kg)[4]

Humber 15/40 engine
Overview
Manufacturer	Humber Limited
Combustion chamber
Configuration	Straight 4-cylinder[8]
Displacement	2,815 cc (171.8 cu in)[8]
Cylinder bore	80 mm (3.15 in)[8]
Piston stroke	140 mm (5.51 in)[8]
Output
Power output	40 bhp (30 kW; 41 PS) @not provided rpm Tax horsepower 15.6[1]

The 15-40-hp, a lightly revised 15.9, was displayed at the Olympia Motor Show in October 1924.

Engine

Some trouble has been taken to dampen engine vibration. The engine and separate gearbox are on a subframe. The engine is flexibly held by two sets of enclosed springs at the front end and at the back by semi-circular steel trunnion blocks. These blocks are secured by spring-loaded bolts. This way the engine is held firmly in a fore and aft position but can swing to the limits of the two sets of enclosed front springs.^[10]

Bodies

Each body has four instead of three doors. The rear seats are wider incorporating the space above the wheel arches,^[9] the mudguards built closer to the wheels to reduce mud splashing. The saloon landaulette's solo occasional seat is now a pair and they fold into the partition below the glass division.^[9]

1926 tourer The petrol filler is no longer beneath any luggage on the grid but out to the side.[10] All-weather equipment is better, The side screens in their stiff metal frames are glazed with celluloid as before but they are now part of the body, they fold within the lower half of the door. Each frame edge overlaps the next.[9] Humber's advertising said: "Exclusive! Ready-In-a-Moment All-Weather-Windows and One-Man Hood."

Brakes, suspension

The 15-40-hp is fitted with Humber-Perrott semi-servo front wheel brakes. The driver's foot pedal still works the transmission brake and now the front wheel brakes as well. A floating shoe gives the semi-servo effect and it relies to some extent on forward motion. Applying the brakes when backing the car receives only half the force. Front axle and stub axles are strengthened to accommodate the higher loads from braking, to the same end the springs are wider and there is a new cross tube linking the dumb irons (forward ends of the main longitudinal chassis members). Front brake adjustment is carried out by jacking up that end of the car and the hand operated nuts turned until equal pressure is provided to each wheel.^[9] The following year a compensating device is installed between the two sets of brakes.^[8]

Shock absorbers are now fitted to the front as well as to the back suspension.^[10]

Test

When the 15/40 was tested by The Times in August 1924 the report ended "travelling was a pleasure".^[10]

References

1. Motor Show. The Times, Monday, Nov 10, 1919; pg. 19; Issue 42253
2. Cars Of To-Day. The Times, Tuesday, Mar 14, 1922; pg. 8; Issue 42979
3. Cars Of To-Day. The Times, Tuesday, Jan 29, 1924; pg. 7; Issue 43561
4. Culshaw and Horrobin (1974). Complete Catalogue of British Cars London: Macmillan. ISBN 0-333-16689-2.
5. Michael Sedgwick and Helen Marshall, Cars of the 1930s, Batsford, London, 1970 ISBN 0713404655
6. Humber Models at Olympia. The Times, Monday, Nov 07, 1921; pg. 5; Issue 42871
7. The Motor Show. The Times, Tuesday, Nov 06, 1923; pg. 20; Issue 43491
8. The Motor Show. The Times Tuesday, Oct 13, 1925; pg. 8; Issue 44091
9. The Motor Show. The Times, Monday, Oct 20, 1924; pg. 23; Issue 43787
10. Cars Of To-Day. The Times, Tuesday, Aug 24, 1926; pg. 6; Issue 44358

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