Ireland Neptune
| {{Infobox aircraft begin
| name=Neptune | image=File:Ireland N-2 Neptune Aero Digest December 1928.jpg | caption=first N-2B in 1928 }}{{Infobox aircraft type | type=Four or five seat cabin flying boat biplane, some amphibious. | national origin=United States | manufacturer=Ireland Aircraft (later renamed Amphibions, Inc) | designer= | first flight=1927 | introduced= | retired= | status= | primary user= | more users= | produced= | number built= about 56 | program cost= | unit cost= | developed from= | variants with their own articles= }} |
The Ireland Neptune was a four or five place pusher configuration biplane sold in flying boat and amphibian versions. Designed in the U.S. and first flown in 1927, well over 50 were built.
Design and development
File:Ireland N-1B Neptune 3-view Aero Digest June 1927.jpg
File:Ireland N-2C Neptune Aero Digest March,1930.jpg
The Neptune was a biplane with a single, pusher configuration engine mounted just under the upper wing and with a conventional hull. The 1927 type N-1B was initially advertised with engines in the {{cvt|90-220|hp|kW}} power rang and an early 3-view shows it with an inline engine, but it first flew in late 1927 with a {{cvt|220|hp|kW}} Wright J-5-C radial. About five more of this flying boat sub-type were built but, despite the 220 hp Wright, they were underpowered when loaded and so most were re-engined into N-2Bs.
This was also a flying boat. It had a {{cvt|300|hp|kW}} Wright J-6-9 but was otherwise similar to the N-1B. The N-2C which followed it into production was an amphibian and had a further 50% power increase from its heavier {{cvt|450|hp|kW}} Pratt & Whitney R-1340 Wasp. The power increase required a new, three-bladed propeller in place of the earlier, {{cvt|8|ft|m}}, 2-bladed one used by the N1-B and it had a swept upper wing and a {{cvt|1|ft|mm}} increase of lower span.
The Neptune was an unequal span single bay biplane with its lower wing on top of the hull and close to the water but with a wide interplane gap. The lower wing had a span 85% of the upper and was significantly narrower, but only it carried dihedral. The wings were rectangular in plan out to rounded tips apart from a central cut-out in the upper trailing edge for propeller rotation. Frise-type, Alcad covered ailerons were fitted only on the upper wings. Both wings were built around spruce spars and were fabric covered and braced together by pairs of outward-leaning parallel interplane struts. The upper centre-section was mounted over the hull on a pair of sturdy N-form struts which were also the main engine supports. Leading edge sweep on the N2-C was about 7°.
The hull had a Cr/Mo steel tube structure which was Alcad clad. The planing bottom had a shallow V-section and a single step under the wing, though it ended abruptly mid-way between wing and tail. Stability on the water was provided by small floats mounted below the interplane struts. The first few N-2Bs had open cockpits but most had glazed cabins like that of the N-1B, as did the N-2C. Crew and passengers were accommodated in two rows of side-by-side seats with the pilot's seat, on the front row, well ahead of the upper leading edge. Entry was via upward-opening doors
Behind the wings the hull tapered to a conventional tail. Its fin was broad and tetrangular in profile, carrying a large balanced rudder. A small, near-rectangular tailplane was mounted on top of the fin, braced by inverted V-struts to the hull. The elevators were larger and balanced, separated by a cut-out for rudder movement. The tailplane was structurally similar to the wings but the other tail surfaces had metal frames. All were fabric-covered.
The amphibious N-2C had mainwheels on short oleo strut legs close to the hull sides with rear drag struts and an oleo tailskid at the extreme rear fuselage. Wheel retraction was manual and took about 30 seconds.
Operational history
About 46 flying boats and 10 amphibians were completed, though histories are sparse. Two at least were used by Curtiss Flying Services, an air-taxi service, the first from mid-winter 1927-8 along the New England coast joined by another based in Florida a year later.
Variants
;N-1B Neptune: 1927 four seat amphibian with a 9 cylinder {{cvt|220|hp|kW}} Wright J-5. About six built.
;N-2B Neptune: 1928 five seat flying boat with a 9 cylinder {{cvt|300|hp|kW}} Wright J-6-9. About 40 built.
;N-2C Neptune: 1929 five seat amphibian with a 9 cylinder {{cvt|450|hp|kW}} Wasp C. 10 built.
;N-2D Neptune: 1929 = 300hp Wright J-6 pusher.
;ND-5: 1929 - 5pCBAm; 450hp Wasp pusher.
;ND-6: 1929 - ND-5 with 300hp Wright J-6 pusher.
Operators
; Curtiss Flying Services
Specifications (N-2C)
{{Aircraft specs
|prime units?=imp
|genhide=
|crew=One
|capacity=Three
|length m=
|length ft=31
|length in=
|length note=
|span m=
|span ft=
|span in=
|span note=
|upper span m=
|upper span ft=40
|upper span in=
|upper span note=
|lower span m=
|lower span ft=35
|lower span in=
|lower span note=
|height m=
|height ft=12
|height in=2.5
|height note=
|wing area sqm=
|wing area sqft=376
|wing area note=
|aspect ratio=
|airfoil=Curtiss C-72
|empty weight kg=
|empty weight lb=3240
|empty weight note=
|gross weight kg=
|gross weight lb=4900
|gross weight note=
|max takeoff weight kg=
|max takeoff weight lb=
|max takeoff weight note=
|fuel capacity={{cvt|85|USgal| Impgal l}}
|more general=
|eng1 number=1
|eng1 name=Pratt & Whitney R-1340 Wasp (Wasp C)
|eng1 type=nine cylinder radial in pusher configuration
|eng1 kw=
|eng1 hp=425
|eng1 note=
|power original=
|more power=
|prop blade number=3
|prop name=Hamilton-Standard
|prop dia m=
|prop dia ft=
|prop dia in=
|prop dia note=
|perfhide=
|max speed kmh=
|max speed mph=120
|max speed kts=
|max speed note=
|cruise speed kmh=
|cruise speed mph=95
|cruise speed note=
- Landing speed: {{cvt|48|mph|km/h kn}}
|stall speed kmh=
|stall speed mph=
|stall speed kts=
|stall speed note=
|never exceed speed kmh=
|never exceed speed mph=
|never exceed speed kts=
|never exceed speed note=
|range km=
|range miles=380
|range nmi=
|range note=
|endurance=
|ceiling m=
|ceiling ft=16000
|ceiling note=
|g limits=
|roll rate=
|glide ratio=
|climb rate ms=
|climb rate ftmin=900
|climb rate note=
|time to altitude=
|sink rate ms=
|sink rate ftmin=
|sink rate note=
|lift to drag=
|wing loading kg/m2=
|wing loading lb/sqft=
|wing loading note=
|fuel consumption kg/km=
|fuel consumption lb/mi=
|power/mass=
|more performance=
|avionics=
}}
Notes
References
Further reading
{{Commons category|Ireland N-2 Neptune}}
- {{cite book |title=Jane's All the World's Aircraft 1928 |editor1-last=Grey |editor1-first=C.G. |year=1928 |publisher=Sampson Low, Marston & Company, Ltd |location=London }}
Category:Single-engined pusher aircraft