The Beechcraft D-18 also known as the “Twin Beech” is a twin engine, low wing, tailwheel aircraft that could carry 6-11 passengers built by Beech Aircraft Corporation of Wichita, Kansas.
This aircraft was produced from 1937 to November 1969, a period of 32 years. There were over 9,000 built making it one of the worlds’ most widely used light aircraft. It had many uses cargo, passenger, VIP aircraft and many uses in the military as transport.
During and after World War Ii it was used by the military besides being a great transport, navigational trainer, bombing trainer, gunnery training, photo recon, drone target puller. The aircraft identifiers when used by the United States Army air Force (USAAF) were C-45 Expeditor, AT-7 Navigator, UC-45 Navigator and with United States Navy (USN) SNB-1 and SNB-2.
In the early pre- WWII days, it was the pre-eminent “business aircraft” and “feeder airliner”. Later it was used in civil purposes as: aerial spraying, sterile insect release, aerial firefighting, air mail delivery, air ambulance, movie productions, skydiving, freight hauling, weapon/drug smuggling (when the smugglers got caught, an aircraft auction occurred) the D-18 was also a skywriter and banner towing.
Many Beech D18s are privately own in the world with 240 registered with the United States Federal Aviation Administration.
On a personal note: I got my first twin-engine time as a young pilot, flying the D-18 on FAA radar testing station in Fontana CA. It was quite a thrill.
Design and Development
The Beechcraft Aircraft Corp. management speculated that the Model 18 design would be in demand during the mid to late 1930s. The Wichita plant was geared up for the production rush which came in 1937.
The design was pretty standard at the time, twin-engines, all-metal fuselage with fabric control services, tailwheel with a less conventional twin ruddier tail assembly.
The Model 18 could be misidentified as the Lockheed Electra which was larger but very similar appearance. Beechcraft used by Jacobs L-68 330 hp radial engines or the Wright R-760Es rated at 350 hp. Shortly the Pratt and Whitney R-885 450hp was developed and became the standard for production Model 18.
During the 32 years of production, there were 32 design modifications from more powerful engines to larger cabins, tricycle landing gear was introduced. There were D-18s built as seaplanes, some equipped with turboprop engines (later years).
One was modified to look like a miniature Lockheed Constellation, another had a long slender nose with a single rudder assembly. The final D-18 model known as the H-18 went to Japan Airlines in 1970.
Model 18 or D-18 production had been rather slow at the start of the entry of the United States into World War II with only 39 aircraft sold (mostly to civil operators). The military immediate need was a trainer aircraft for pilots, bombardiers, and navigators.
A military version was designed that became the AT-7 for USAAF and the SNB for USN. This eventually led to a more advanced mode the AT-11 and the ANB-2 trainers. The standard C-45 transport version was also in the production line.
At the end of World War II, unlike a lot of aircraft built for the military which was moth-balled or cut up, the D-18 continued in production with new versions as technology and needs advanced. The AT trainers continued to be produced with new features and many modifications for many new uses.
In 1951-1955 time frame about 900 USAF older D-18 models were re-manufactured to D-18S models which at the time was current. The USN had many of it’s older aircraft remanufactured and redesigned SNB-5 and SNB-5P.
The Beech D-18 was used extensively by Air America during the Vietnam War. Most of Air America’s aircraft were standard C-45, but 12 of them were re-modified to what they called Conrad Ten-Two which had increased performance and load capability.
The numerical name was to designate their maximum takeoff weight of 10,200 lbs. The aircraft was powered by Garrett AirResearch TFE-331 turboprop engines. The C-45 flew in the USAFF until 1963, USN flew their SBN models until 1972 the United States Army (USA) continued to use C-45 after USAF separation in 1947 until 1976.
Examples of D-18 Variants:
- Model 18A had 2 pilots, seven or eight passengers using Wright R760E radials of 320hp with a MTOW (max takeoff weight) of 6,700 lbs.
- Model 18D had 2 pilots, nine passengers with Jacobs L-6 radials of 33o hp and an MTOW 7,200lbs
- Model 18R had 2 pilots, nine passengers with Pratt and Whitney R 985-A1 radial with a dual-stage blower rated at 450hp
Where you can see the Beechcraft Model 18 (All Variants)
SBN-2 2C-29646 Pima Air and Space Museum Tucson, Arizona
AT-11 42-37240 Lone Star Flight Museum Galveston, Texas
AT-11 42-37240 Barksdale Global Power Museum Bossier City, Louisiana
UC-45 42-37496 Wings over the Rockies Air and Space Museum Denver, Colorado
UC-45F 44-47342 Alaska Aviation Heritage Museum Anchorage, Alaska
TC-45H 51-11529 Tr-State Warbird Museum Batavia, Ohio
C-45H 51-11696 Museum of Flight Seattle, Washington
C-45G 51-11795 Air Mobility Command Museum Dover, Delaware
C-45G 51-11897 Castle Air Museum Atwater, California
C-45H 52-10539 1941 Historical Aircraft Group Museum Geneseo, New York
C-45H 52-10865 Travis Air Force Base Heritage Center Travis AFB, California
C-45H 52-10893 National Museum of the United States Air Force Dayton, Ohio
UC-45j 23774 Laughlin AFB Del Rio, Texas
RC-45J 51233 Tennessee Museum of Aviation Sevierville, Tennessee
UC-45J 51242 CAF Center Wing San Marcos, Texas
UC-45J 51291 Aerospace of California Sacramento, California
UC45J 51338 Minnesota Air National Guard St. Paul, Minnesota
S18D 178 Beechcraft Heritage Museum Tullahoma, Tennessee
C-45H AF-824 Beechcraft Heritage Museum Tullahoma, Tennessee
E18S BA-453 Beechcraft Heritage Museum Tullahoma, Tennessee
H-18 BA-670 Lone Star Flight Museum Galveston, Texas
This is Just a Partial List of the Beech D-18 on Display. Check With Your Local Air Museum for More Information.
Tech Specs for the UC-45 Expeditor
Wingspan: 47 ft 8 in
Length: 34 ft 2 in
Height: 9t 8 in
Weight: 6,175 lbs (empty): 8,727 lbs MTOW
Max Speed: 225 mph
Ceiling: 26,000 ft
Range: 1,200 mi at 160 mph
Engines: 2/Pratt & Whitney R-985-AN-1 Wasp Junior radial engines rated at 450 hp each