De Havilland DH34
 

A large single engine biplane designed as a follow-on to the Airco DH18.
De Havilland DH34 prototype G-EBBQ The prototype De Havilland DH34 G-EBBQ in Daimler Hire colours.
 
In the very early 1920s, the De Havilland Aircraft Company recognised the need for increased capacity to improve the economics of passenger transport operations.
 
The De Havilland DH29, their ten seat monoplane, had suffered with significant low speed handling issues and so the company opted for a relatively conventional biplane for their next commercial design, the De Havilland DH34.
 
The prototype De Havilland DH34 (G-EBBQ) flew for the first time on 26th March 1922, and it was delivered just a few days later to Daimler Hire Ltd who immediately commenced passenger services to Paris, which were inaugurated on 2nd April 1922.
 
Carrying up to 10 passengers, the De Havilland DH34s were used heavily on the cross-channel air services, with the fleet flying more than 8,000 hours in their first nine months of operation. Such was their durability that the second aircraft flew over 100,000 miles without overhaul.
 
The plywood covered fuselage featured an enclosed passenger cabin with two pilots, seated side-by-side. They were positioned immediately ahead of the wings but behind the Napier Lion engine in an open cockpit, high up in the nose of the aircraft. In fact the pilots position was so high up that a distinctly non-aerodynamic external ladder was provided to allow the crew to reach it. The engines were fitted with inertia starters thus avoiding the necessity for hand-swinging of propellers.
 
Unusually, the passenger cabin was designed to allow a spare engine to be carried across the rear with the unusual shape of the cabin door allowing the engine to be loaded and unloaded with a degree of ease. Spare engines were not always routine cargo but the facility allowed operators to combine maintenance and service requirements with fare paying flights. In this passenger / cargo configuration, a specially-fitted removable 'porthole' on the other side of the cabin allowed the propeller boss to protrude out of the side of the aircraft.
 
A total of eleven DH34s were built with a number of them being modified 'in-service' to De Havilland DH34B specification with an increased wing span and surface area. The increase in wing area from 590 sq ft to 637 sq ft reduced the landing speed by some 7 mph, without significantly affecting the type’s cruise performance. This modification was intended to lower the landing speed to 70 mph, which was still regarded as high at the time.
 
De Havilland DH34 G-EBCX Refuelling De Havilland DH34 G-EBCX with the aid of a long ladder.
 
In addition to Daimler Hire Ltd, the type was flown by Instone Air Lines who used their four aircraft on combined European destinations including Amsterdam, Brussels, Cologne and Berlin.
 
Twelve De Havilland DH34s were allocated construction numbers, although it is believed that the final one (G-EBCY) may not have been completed.
 
Although they were very successful and reliable in service, five aircraft were destroyed in accidents whilst at least one aircraft was exported to Russia.
 
Six De Havilland DH34s were passed to Imperial Airways upon its formation in 1926, but they decided to select multi-engine aircraft for their passenger operations. Consequently, the remaining De Havilland DH34s were withdrawn from service at the end of March 1926, before finally being dismantled at Croydon Airport.

 

Specification


  (DH34 and DH34B unless otherwise noted)
Powerplant One 450 hp Napier Lion engine
Span DH34 51 ft 4 in; DH34B 54 ft 4 in
Maximum Weight 7,200 lb
Capacity Two pilots in an open cockpit and seats for nine passengers in an enclosed cabin 
Maximum Speed 128 mph
Cruising Speed 105 mph
Range 365 miles

 

Variants & Numbers Built


DH34 Production standard (12, of which 11 aircraft are known to have been completed)
DH34B Three aircraft modified with increased wing span and area (G-EBBT, ‘BBX, ‘BBY)

 

Survivors


None