Supermarine Seamew

Supermarine

Industry	Aerospace
Founded	1913
Headquarters	Southampton , United Kingdom

For similarly named aircraft, see SO3C Seamew and Short Seamew.

The Supermarine Seamew was a British twin-engine amphibious aircraft constructed by Supermarine at their Woolston, Southampton facility. Designed as a compact, shipborne reconnaissance aircraft, it was developed between 1925 and 1927 under the guidance of R. J. Mitchell to fulfill the Air Ministry’s specification 29/24. Notably, it was Supermarine’s first aircraft to incorporate metal into its structure; only two units were produced. Mitchell also envisioned a civilian variant capable of carrying up to six passengers.

Due to higher priority projects, development on the Seamew was limited until October 1926. Its maiden flight occurred on 9 January 1928. Evaluation revealed that the aircraft exhibited a nose-heavy tendency and suffered from defective hand-starter mechanisms. The placement of the propellers was suboptimal, resulting in damage from sea spray over time. Additional testing uncovered that some fittings were fabricated from inappropriate materials. Both examples were ultimately dismantled in 1930.

Design and development

In October 1924, Supermarine’s chief designer R.J. Mitchell produced the initial concept for a new amphibious aircraft intended for reconnaissance. The crew arrangement included three members: the pilot seated in the forward cockpit, a gunner positioned behind the pilot but ahead of the lower wing, and a rear gunner located aft of the lower wing. A revised design dated 5 January 1925 adjusted the rear gunner’s position closer to the wings and relocated the tailskid accordingly. Based on these plans, the Air Ministry commissioned two aircraft to satisfy specification 29/24, assigning serial numbers N212 and N213. The designation Seamew was assigned to this model. By February 1926, Mitchell had finalized detailed drawings, including modifications to the fin and rudder. He also proposed an alternative version designed for civilian use with seating for up to six passengers.

The aircraft employed two 238 horsepower (177 kW) geared Armstrong Siddeley Lynx IV radial engines driving wooden tractor propellers. Fuel was stored in a gravity-fed tank mounted atop the upper wing. A 1929 report in Flight magazine estimated that its 135 imperial gallons (610 L; 162 US gal) petrol capacity provided an operational range near 300 miles (480 km).

The Seamew featured wings with a span of 46 feet (14 m), engineered to fold backward along the hull for shipboard storage. Mitchell selected a thick high-lift aerofoil section—the Göttingen 387 profile—to enable low-speed flight without stalling when fully loaded. This model marked Supermarine’s initial use of metal in construction; the spars were crafted from Duralumin, an aluminium–copper alloy. The wooden hull measured 35 feet (11 m) in length and stood 13 feet 1 inch (3.99 m) tall, essentially a reduced-scale version of the Supermarine Southampton. The mainplanes were covered with fabric.

Throughout 1925, Supermarine concentrated primarily on developing other projects such as the Southampton, Seagull V, and Supermarine S.4. Consequently, progress on the Seamew remained minimal until October 1926. Further delays arose in 1926 due to work on the Supermarine S.5, Supermarine Nanok, and Supermarine Sparrow II, as well as required modifications to the Southampton, postponing Seamew development until late that year. The first prototype took flight on 9 January 1928 under test pilot Henri Biard but was already nearing obsolescence by that time.

Testing and operational history

The Seamew underwent evaluation at the Marine Aircraft Experimental Establishment, the Air Ministry's testing site located at RAF Felixstowe. During trials, it was found that the hand-starter mechanism frequently malfunctioned, and when fully loaded, the propellers were damaged by sea spray during takeoff. Due to the aircraft's tendency to be nose-heavy, which hindered its ability to climb effectively at optimal speeds, Supermarine addressed this by installing balanced rudders on the tailplane. After accumulating 66 hours of flight time, N212 experienced a failure in the mainplane fitting, which was later attributed to the use of stainless steel in its construction. In March 1930, Supermarine explored the possibility of upgrading the Seamew's engine to enhance its performance, but this plan was ultimately discarded.

On 12 April 1930, N212 was involved in an accident while taxiing on the slipway at Felixstowe. This mishap, combined with the anticipated costs of fabricating new mainplane fittings and reconstructing the airframe, resulted in both aircraft being dismantled within the same year.

The Seamew contributed valuable insights into aerofoil design for Mitchell, which were subsequently applied in developing the wing of the Spitfire. The second aircraft, N213, was equipped with smaller propellers; however, this change led to a reduced climb rate. To overcome this issue, Supermarine went on to design the Seagull V and the Sea Otter, each powered by a single engine.

Specifications

{{Aircraft specs |ref=Supermarine Aircraft since 1914 |prime units?=imp |crew=2–3 (pilot plus one or two gunners) |length ft=36 |length in=5+5/8 |length note= |span ft=45 |span in=11+1/2 |span note= |height ft=15 |height in=1 |height note= |wing area sqft=610 |wing area note= |aspect ratio= |airfoil=Goettingen 387 |empty weight lb=4675 |empty weight note= |gross weight lb=5800 |gross weight note= |max takeoff weight lb= |max takeoff weight note= |fuel capacity= |more general= |eng1 number=1 |eng1 name=Armstrong Siddeley Lynx IV |eng1 type=7-cylinder air-cooled radial piston engine |eng1 hp=238 |eng1 note=

|prop blade number=2 |prop name=fixed-pitch wooden propellers |prop dia ft=10 |prop dia in=0 |prop dia note=

(N213, the second Seamew, featured 4-bladed 8 ft (2 m) diameter propellers designed to minimize damage from water impact).

|max speed mph=95 |max speed note= |cruise speed mph= |cruise speed note= |stall speed mph= |stall speed note= |never exceed speed mph= |never exceed speed note= |range miles= |range note= |ferry range miles= |ferry range note= |endurance= |ceiling ft=10950 |ceiling note= |climb rate ftmin=523 |climb rate note= |time to altitude= |lift to drag= |wing loading lb/sqft= |wing loading note= |fuel consumption lb/mi= |power/mass= }