All Aero

The Twin Bonanza first flew in November 1949 (TC 5A4). Widening the Model 35 Bonanza fuselage to accommodate three abreast and placing an engine on each wing equalled the Twin Bonanza.

The US military used the Twin Bonanza as the L-23 Seminole, redesignated as U-8 in 1962. Four YL-23 were purchased in 1952 [52-1800/1803]. These were followed by 55 L-23A models [52-6162/6216] (most rebuilt later as L-23D.

Forty L-23B [53-6153/6192] were purchased and a single XL-23C [55-3465] in 1955, converted to U-8G.

L-23 trials included “flying fuel tanks” to greatly increase fuel loads with the extra wing area attached to the tanks offsetting the greater weights involved.

Both civil and military versions continued to be developed through various marks. By 1955, 96 L-23As and Bs were built.

In 1958 the US Army sought an upgrade which lead to the development of the L-23F with its enlarged cabin.
It was the first post-war light twin to reach quantity production in the United States, and late models grossed 7300 pounds. Built with 260, 275, 295, and 340-hp Lycoming engines, the Twin Bonanza design has proved highly versatile. Beech produced the military U8 Seminole, the civil Queen Air and early King Airs from the Twin Bonanza wing, and Swearingen has marketed a conversion of the basic Twin Bonanza as the Excaliber.

The design started life as a six-seater, and a seventh was added on the J model in 1960. There is so much room inside that numerous luxury executive interiors have been custom-installed. The aircraft has also been successful as an ambulance plane with room for a stretcher and medical attendants, in addition to the crew.

From the L23F derivative of the Model 50 Twin Bonanza Beech developed the civil Model 65 Queen Air with it first flying on 28 August 1958.

Gallery

B50
Cruise: 190 mph
Range: 1088 mi
Seats: 6

C50
Engines: two 275-hp Lycoming GO-480-F6
Wing span: 45 ft 3.5 ft
Wing area: 277.06 sq.ft
Length: 31 ft 6.5 in
Height: 11 ft 4 in
Gross Wt. 5500 lb
Empty Wt. 3800 lb
Fuel capacity 33 USG
Top 205 mph
Cruise 65%: 197 mph at 10,000 ft
Stall 64 mph
Initial climb rate 1450 fpm
Ceiling 20,000 ft
Range 920 sm
Takeoff distance (50’) 1350 ft
Landing distance (50’) 1210 ft
Seats 4-6

D50A-E
Engines two 295-hp Lycomings
Seats 6.
Gross Wt. 6300 lbs.
Empty Wt. 3981 lbs.
Fuel capacity 180 USG.
Top speed 214 mph.
Cruise 203 mph.
Stall 71 mph.
Initial climb rate 1450 fpm.
Ceiling 20,000 ft.
Range 1650 sm.
Takeoff distance (50’) 1260 ft.
Landing distance (50’) 1452 ft.

Beechcraft 1958 D50A Twin Bonanza
Engine: Lyc. GO-480G2D6, 295 hp
TBO: 1400 hr
Fuel type:100LL
Propeller: Const. spd.
Landing Gear type: Tri./Retr.
Gross weight: 6300 lb
Empty weight, std: 4090 lb
Useful load: 2210 lb
Fuel: 134 USgal
Payload, full std. fuel: 624 lb
Wingspan: 45 ft. 3 in.
Overall length: 31 ft. 6.5 in.
Height: 11 ft. 4 in.
Wing area: 277 sq. ft
Seating capacity: 7
Cabin width: 54 in
Cabin height: 51 in
Baggage capacity: 500 lb
Cruise speed, 8,000 ft 75% power: 203 kt
Cruise speed, 8,000 ft 65% power: 201 kt
Max range (w/ res) 65% power: 825 nm
Fuel consumption 70% power: 37 US gph
Fuel consumption 65% power: 34 US gph
Stall speed (gear, flaps down): 71 kt
Best rate of climb: two engines: 1450 fpm
Best rate of climb: one engine: 300 fpm
Service ceiling two engines: 20,000 ft
Service ceiling one engine: 7000 ft
Takeoff ground roll: 905 ft
Landing ground roll: 700 ft

Beechcraft E-50 Twin Bonanza
Business Twin, USA, 1957
Engine : 2 x Lycoming GSO 480 B1 B6, 316 hp
Length: 31.529 ft / 9.61 m
Height : 11.516 ft / 3.51 m
Wingspan : 45.21 ft / 13.78 m
Wing area : 276.958 sq.ft / 25.73 sq.m
Max take off weight : 4795.9 lb / 2175.0 kg
Weight empty : 5009.8 lb / 2272.0 kg
Max. weight carried : 1991.1 lb / 903.0 kg
Max. speed : 198 kt / 366 km/h
Initial climb rate : 1614.17 ft/min / 8.20 m/s
Service ceiling : 24606 ft / 7500 m
Wing load : 17.43 lb/sq.ft / 85.0 kg/sq.m
Range : 864 nm / 1600 km
Endurance : 5 h
Crew : 2+5

J50
Engines two 340-hp Lycomings.
Seats 6-7.
Gross Wt. 7300 lbs.
Empty Wt. 4460 lbs.
Fuel capaci.ty 230 USG.
Top speed 235 mph.
Cruise 223 mph.
Stall 82 mph.
Initial climb rate 1270 fpm.
Range 1650 sm.
Ceiling 29,150 ft.
Takeoff distance (50’) 1450 ft.
Landing distance (50’) 1840 ft.

Excalibur / Beech Twin Bonanza
Engines: 2 x Lycoming IGSO-540-A1A, 380 hp.
Seats: 6/7.
Wing loading: 22.7 lb/sq.ft.
Pwr loading: 9.6 lb/hp.
Max TO wt: 7300 lb.
Empty wt: 4768 lb.
Equipped useful load: 2200 lb.
Payload max fuel: 820 lb.
Range max fuel/ 75% cruise: 797 nm/3.5 hr.
Range max fuel / 55% cruise: 1343 nm/ 6.7 hr.
Service ceiling: 30,000 ft.
75% cruise: 226 kt.
55% cruise: 202 kt.
Vmc: 78 kt.
Stall: 72-78 kt.
1.3 Vso: 93 kt.
ROC: 1900 fpm.
SE ROC: 340 fpm @ 102 kt.
SE ceiling: 17,500 ft.
Min field length: 2612 ft.
Fuel cap: 1380 lb.

Excalibur Excalibur 800 / Beech Twin Bonanza
Engines: 2 x Lycoming IO-720-A1B, 400 hp.
Seats: 6/7.
Wing loading: 22.7 lb/sq.ft.
Pwr loading: 9.5 lb/hp.
Max TO wt: 7600 lb.
Empty wt: 4768 lb.
Equipped useful load: 2500 lb.
Payload max fuel: 1120 lb.
Range max fuel/ 75% cruise: 901 nm/4.4 hr.
Range max fuel / 55% cruise: 1156 nm/ 6.3 hr.
Service ceiling: 22,200 ft.
75% cruise: 204 kt.
55% cruise: 185 kt.
Vmc: 78 kt.
Stall: 71-80 kt.
1.3 Vso: 92 kt.
ROC: 1870 fpm.
SE ROC: 440 fpm @ 102 kt.
SE ceiling: 11,800 ft.
Min field length: 2178 ft.
Fuel cap: 1380 lb

YL-23

L-23A
Engines: 2 x 260hp O-435

L-23B
Engines: 2 x 260 h.p. Lycoming GO-435-17
Span: 45 ft. 3 in.
Weight: 5.500 lb.
Max. Speed: 202 m.p.h.
Sats: 6
Range: 985 miles at 190 m.p.h.

XL-23C

L-23D / E/F-50 / U-8D / RU-8D / RU 8D Seminole
1958
Engines: 2 x 340hp O-480
Useful load: 2026 lb
Max speed: 233 mph
Cruise speed: 203 mph
Range: 1355 mi
Seats: 6
No built: 85 [56-3695/3718, 57-6029/6094, 57-3084/3101, 58-1329/1353, -1357/1364, -3048/3092, 59-2535/2543, -4990/4992], included remanufactured L-23As.

RL 23D
Radar photo-observation, from civil E50
No built: 9

L-23E / U-8E / D-50
Engines: 2 x 295hp GO-480
No built: 6 [56-4039/4044], plus 1 civil to military to civil [N1779G=66-15360=N5375G=N888JE=N74GV].

U-8G Seminole
Conversion of L-23D/23E
No built: 23 [55-3465, 56-3710, -4039, -4041, -4043, -4044, 57-6085 -6089, 58-1329, -1336, -1348, -1357, -1359/1360, -1363, -1364, -3055, -3057, -3062, 59-2536/2538, -4990].