View source for Miles M.15

{{Use dmy dates|date=September 2017}}
{{Use British English|date=September 2017}}
{|{{Infobox Aircraft Begin
 | name= Miles M.15
 | image=M15II.jpg
 | caption=Trainer MKII
}}{{Infobox Aircraft Type
 | type= Two-seat basic trainer
 | national origin= [[United Kingdom]]
 | manufacturer= [[Miles Aircraft|Phillips and Powis Aircraft Ltd, Reading]]
 | designer= 
 | first flight= Probably 22 September 1938
 | introduced=
 | retired= 1940
 | status=
 | primary user=
 | number built=2
 | developed from= 
 | variants with their own articles=
}}
|}

The '''Miles M.15''' was a 1930s [[United Kingdom|British]] single-engined monoplane [[Trainer (aircraft)|trainer aircraft]] with two open cockpits, designed and developed by [[Miles Aircraft]]. Like other aircraft constructed to the official specification, it failed to meet the performance requirements, and only two were built.

==Development==
The Miles M.15<ref name ="Lukins">{{Harvnb|Lukins|1945|pages=52–3}}</ref> was built in response to [[List of Air Ministry Specifications#1920-1929|Air Ministry specification T.1/37]] which called for a two-seat basic trainer. Two other aircraft manufacturers also built contenders: [[Parnall Aircraft]] provided the [[Parnall Heck|Heck 3]] and [[Heston Aircraft]] their [[Heston T.1/37]]. The [[Airspeed]] AS.36, [[General Aircraft]] GAL.32 and [[Percival Aircraft|Percival]] P.20 were also proposed against specification T.1/37, but not built. At first sight, the M.15 looked rather like the earlier [[Miles Magister]], a low cantilever wing monoplane with tandem open cockpits and a fixed, spatted main undercarriage plus tailwheel, powered by a single inverted [[de Havilland Gipsy]] series in-line engine. Despite this, the two types differed significantly in powerplant, form and construction.

The M.15<ref name='Brown, 1970'>{{Harvnb|Brown|1970|pages=147}}</ref> was powered by a 200&nbsp;hp (149&nbsp;kW) [[de Havilland Gipsy Six|Gipsy Six]] 6-cylinder engine, much more powerful than the Magister's 130&nbsp;hp (97&nbsp;kW) [[de Havilland Gipsy Major|Gipsy Major]]. Partly as a result, the M.15 was about 4&nbsp;ft 10 in (1.4 m) longer than the Magister. The vertical stabiliser had straight leading and trailing edges, giving it a triangular look compared with the rather pointed Magister surface. Both elevators and the horn-balanced rudder carried trim tabs.  The wingspan of the M.15 was slightly less than that of the Magister, but the planform was more curved along the trailing edge and the total wing area greater. Both types carried mild dihedral outboard of the centre section. A small fairing behind the rear cockpit was another new feature of the M.15.

Both Magister and M.15 were wooden aircraft, built with spruce members with ply covering.  The M.15 fuselage though, was a monocoque structure, much more rounded in cross-section (more visible in the lower half of the fuselage) than the flat-sided and flat-bottomed Magister. The wings were built around two spruce spars with plywood webs and ribs of spruce and ply, the whole structure plywood-covered and, like the fuselage, sheathed in fabric. The unladened M.15 was over 40% heavier than the Magister.

The M.15, like the other contenders for specification T.1/37, failed to satisfy the Air Ministry's requirements. Miles built a slightly modified second (Mk. II) machine with squared-off wings and tailplane to see if performance could be improved, but with little success.  It has been suggested<ref name="Lukins"/> that the constraints of specification T.1/37 made it impossible to achieve the performance goals; true or not, no manufacturer received a production order for an aircraft designed to it.

==Operational history==
The two examples were built by Philips and Powis Aircraft at [[Woodley Aerodrome]]. The first flight was made by H. (Bill) Skinner, probably on 22 September 1938.<ref name ="Amos2009"/> He flew it to [[RAF Martlesham Heath]] for trials on 4 February 1939. The second aircraft (Mk. II) flew under B conditions as U-0234 and later with the serial P6326. Built in response to the results of the T.1/37 trials, it transferred to [[RAE Farnborough]] on 23 May 1939.

==Variants==
;Trainer Mk I
:Prototype trainer, serial L7714 to meet specification T.1/37, one completed and flown, and construction of the second abandoned.<ref name="Amos2009">{{Harvnb|Amos|2009|pages= 280}}</ref>
;Trainer Mk II
:Improved variant built in 1939, included squared wingtips and tailplane, and changes to the two windscreens.<ref name ="Amos2009"/>

==Specifications (Mk I)==
{{aircraft specifications
|plane or copter?= plane
|jet or prop?= prop
|ref=Miles Aircraft Since 1925<ref name='Brown, 1970'/>
|crew=2
|payload main=
|payload alt=
|payload more=
|length main= 29 ft 6 in 
|length alt= 8.99 m
|span main= 33 ft 5 in
|span alt=  10.18 m
|height main= 10 ft 5 in 
|height alt= 3.17 m
|area main= 200 sq.ft
|area alt= 18.57 m²
|airfoil= 
|empty weight main= 1,830 lb 
|empty weight alt= 830 kg
|loaded weight main= 2,530 lb 
|loaded weight alt= 1,148 kg
|useful load main= 
|useful load alt= 
|max takeoff weight main= 
|max takeoff weight alt= 
|max takeoff weight more=
|engine (prop)= [[de Havilland Gipsy Six]] 6-cylinder inverted inline
|type of prop= <!-- meaning the type of propeller driving engines -->
|number of props= 1<!--  ditto number of engines-->
|power main= 200 hp 
|power alt= 159 kW
|power original=
|power more=
|propeller or rotor?=propeller
|propellers=fixed pitch
|number of propellers per engine= 
|propeller diameter main=
|propeller diameter alt= 
|max speed main= 
|max speed alt= 
|max speed more= 
|cruise speed main= 
|cruise speed alt=
|cruise speed more 
|stall speed main= 
|stall speed alt= 
|stall speed more=
|never exceed speed main= 
|never exceed speed alt= 
|range main= 
|range alt=
|ferry range main=
|ferry range alt=
|ferry range more=
|ceiling main= 
|ceiling alt= 
|climb rate main= 
|climb rate alt= 
|loading main=
|loading alt=
|thrust/weight=
|power/mass main=
|power/mass alt=
|more performance=

}}

==References==
{{commons category|Miles M.15}}

===Notes===
{{reflist}}

===Bibliography===
{{refbegin}}
*{{cite book |last=Amos |first= Peter |authorlink= |title= Miles Aircraft - The Early Years|year=2009 |publisher= Air-Britain|location= Tonbridge, Kent, England |isbn=978-0-85130-410-6|pages=}}
*{{cite book |last= Brown|first= Don L |title= Miles Aircraft Since 1925 |publisher= Putnam & Company |location= UK |year= 1970 |isbn=0-370-00127-3 |page=}}
*{{cite book| title= The Book of Miles aircraft|last= Lukins|first= A.H. |author2=Russell, D.A. |edition= |year=1945|publisher= Harborough|location= Leicester|isbn= }}
{{refend}}

<!-- ==External links== -->
{{Miles aircraft}}

[[Category:British military trainer aircraft 1930–1939]]
[[Category:Miles aircraft|M.15]]
[[Category:Single-engined tractor aircraft]]
[[Category:Low-wing aircraft]]
[[Category:Aircraft first flown in 1938]]