May was born on 1916 and was from Victoria, British Columbia, Canada.

On 9 January 1938, May was granted a short service commission as Acting Pilot Officer on probation (gazetted on 25 January 1938).

On 25 October 1938, Acting Pilot Officer May was confirmed in his appointment and graded as Pilot Officer (gazetted on 1 November 1938).

Pilot Officer May was promoted to Flying Officer on 25 April 1940 (gazetted on 18 June 1940).

In April 1941, May was serving in 4 SFTS at Habbaniya.

On 25 April 1941, he was promoted to the war substantive rank of Flight Lieutenant (gazetted on 6 June 1941).

In April 1941, seizing the opportunity of Allied reverses in Greece and in North Africa, a pro-Axis coup led by Rashid Ali took place in Iraq.
Invoking longstanding agreements Imperial troops were landed at Basra at the head of the Red Sea. In reprisal on 29 April, a 9000-strong Iraqi force invested the large RAF base at Habbaniya, to the west of Baghdad.
At this time some reinforcements of the flying training school there had taken place, including the delivery of six Gladiator Mk.Is (from stocks in Egypt) that joined three other Mk.Is on 19 April in a Fighter Flight under the command of Flight Lieutenant R. S. May. The Fighter Flight was to operate from the base’s Polo Field.

Following the refusal of the Iraqi troops to withdraw from Habbaniya on 1 May, Air Vice Marshal H. G. Smart, Air Officer Commanding in Iraq, on receiving confirmation that the Foreign Office in London considered the Iraqi action as an act of war, now decided that he would attack the Iraqi forces at dawn on 2 May without prior warning.

On the second day of the attack, on 3 May, Iraqi bombers were again caught over the base by the defending fighters, Flying Officer R. B. ‘Dicky’ Cleaver made three passes at a SM.79B, firing 1200 rounds; the bomber departed the area with black smoke streaming from the port engine and diving steeply for the ground.
Flight Lieutenant May attacked a formation of Northrop 8A-4s, and damaged one of them.
It was later discovered that the SM.79B and the Northrop had both force-landed in the desert; subsequently both the pilots had their claims upgraded to confirmed victories.

127 Squadron was formed on 10 June with personnel and instructors from 4 SFTS and its Habbaniya Striking Force.
Flight Lieutenant May became member of this unit on 29 June.

On 12 July 1941, he was posted to Rhodesia as an instructor.

Later in the war, he was posted to Bomber Command and 90 Squadron flying Short Stirlings.

He was promoted to Squadron Leader (temp.) on 1 June 1942 (gazetted on 3 July 1942).

On the night of 28/29 April 1943 (take-off 20:19 from Ridgewell), he was involved in a mine-laying operation (Gardening) off the coast of Holland and Germany, flying Sterling BF346. The raid included totally 207 heavy bombers. His aircraft went missing over the sea off Kiel. His Sterling was probably shot down by a German nightfighter of NJG3, which claimed five Sterlings shot down between 00:12 and 01:48.
Killed together with Squadron Leader May were his crew; Sergeant Leslie Hainin (RAF no. 1267828), Pilot Officer Gerald Frederick Heathcote-Peirson (RAF no. 134917), Sergeant Kenneth George Horne (RAF no. 1320949), Sergeant Norman Marshall (RAF no. 817293), Sergeant Basil Horace Reeve (RAF no. 1388458) and Pilot Officer (Navigator) William Greenhalgh Monk (RCAF no. J/17258).

At the time of his death, May was credited with 1 biplane victory.

Claims:

Kill no.	Date	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1941
1	03/05/41	1	Northrop 8A-4 (a)	Destroyed	Gladiator I		Habbaniya area	Fighter Flight

Biplane victories: 1 destroyed.
TOTAL: 1 destroyed.
(a) First claimed as a damaged but later upgraded to a confirmed.

Sources:
Dust Clouds in the Middle East - Christopher Shores, 1996 Grub Street, London, ISBN 1-898697-37-X
Gloster Gladiator - Alex Crawford, 2002 Mushroom Model Publications, Redbourn, ISBN 83-916327-0-9
Gloster Gladiator Aces - Andrew Thomas, 2002 Osprey Publishing, London, ISBN 1-84176-289-X
Gloster Gladiator Home Page - Alexander Crawford.
Hurricanes over the sands: Part One - Michel Lavigne and James F. Edwards, 2003 Lavigne Aviation Publications, Victoriaville, ISBN 2-9806879-2-8
Nachtjagd War Diaries: Volume One - Theo E. W. Boiten, 2008 Red Kite, ISBN 978-0-9554735-6-2
The Commonwealth War Graves Commission
The London Gazette
Additional info kindly provided by Alexander Crawford.