Beechcraft Model 18 Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.Anti-spam check. Do not fill this in! ==Operational history== [[File:Beech18 on floats.jpg|thumb|Beechcraft 18 on floats]] Production got an early boost when [[Kuomintang|Nationalist China]] paid the company US$750,000 for six M18R light bombers,<ref name="AFB">[http://www.aerofiles.com/_beech.html "Beechcraft page."] ''Aerofiles.'' Retrieved: August 12, 2008.</ref> but by the time of the U.S. entry into [[World War II]], only 39 Model 18s had been sold, of which 29 were for civilian customers.<ref name="BHM18S"/><ref name="BHM"/> Work began in earnest on a variant specifically for training [[United States Army Air Forces]] (USAAF) military pilots, bombardiers, and navigators. The effort resulted in the Army AT-7. Further development led to the AT-11 navigation trainer, C-45 military transport, and F-2 (the "F" standing for "Fotorecon", short for [[Imagery intelligence|"photographic reconnaissance"]]). The [[United States Navy]] first adopted the Beech 18 as the JRB-1, equivalent to the F-2, followed by the JRB-2 transport; the JRB was initially named the '''Voyager''', but this name did not enter common use, and JRBs were generally called Expeditors like their USAAF counterparts.{{sfn|Swanborough|Bowers|1976|p=41}} The first JRB-1 obtained by the Navy, [[bureau number]] (BuNo) ''09771'', was converted from the last civil Model 18 built before production was earmarked solely for the military for the duration of the war.<ref name=Baugher_1>{{cite web |url=http://www.joebaugher.com/navy_serials/thirdseries1.html |title=US Navy and US Marine Corps BuNos, Third Series (00001 to 10316) |last=Baugher |first=Joe |date=16 August 2022 |website=joebaugher.com |access-date=23 August 2022}}</ref> The Navy subsequently obtained more Model 18s as the JRB-3 (C-45B), JRB-4 (UC-45F), SNB-1 Kansan (AT-11), SNB-2 (AT-7), and SNB-2C (AT-7C).{{sfn|Swanborough|Bowers|1976|pp=41β42}} Existing naval Twin Beeches were subsequently modified into the SNB-2H air ambulance, SNB-2P reconnaissance trainer, and SNB-3Q [[electronic countermeasures]] trainer.{{sfn|Swanborough|Bowers|1976|p=42}} The [[United States Coast Guard]] acquired seven JRB-4 and JRB-5 aircraft from the Navy between 1943 and 1947; they were primarily used as utility transports, with one aircraft later converted for aerial mapping, and another used for proficiency flying.<ref name=uscg>{{cite web|url=https://www.history.uscg.mil/browse-by-topic/Aviation/Article/2016419/beech-jrb-45-expeditor/ |title=Beech JRB-4/5 "Expeditor" |publisher=United States Coast Guard |website=www.history.uscg.mil |access-date=23 August 2022}}</ref><ref name=Baugher_cg>{{cite web |url=http://www.joebaugher.com/coastguardseries.html |title=US Coast Guard Aircraft Serials |last=Baugher |first=Joe |date=25 June 2022 |website=joebaugher.com |access-date=23 August 2022}}</ref> After the war, the USAAF became the [[United States Air Force]] (USAF), and the USAF [[Strategic Air Command]] had Model 18 variants (AT-11 Kansans, C-45 Expeditors, F-2 Expeditors, and UC-45 Expeditors) from 1946 until 1951. In 1950, the Navy still had around 1,200 JRB and SNB aircraft in inventory.{{sfn|Swanborough|Bowers|1976|p=42}} From 1951 to 1955, the USAF had many of its aircraft remanufactured with new fuselages, wing center sections, and undercarriages to take advantage of the improvements to the civil models since the end of World War II. Eventually, 900 aircraft were remanufactured to be similar to the then-current Model D18S and given new designations, constructor's numbers, and Air Force serial numbers.<ref name="BHM45">[https://web.archive.org/web/20081231015507/http://beechcraftheritage.com/collection/N7916A.php "C-45H."] ''Beechcraft Heritage Museum''. Retrieved: August 24, 2008.</ref> The USN had many of its surviving aircraft remanufactured as well, resulting in the JRB-6, the SNB-5, and SNB-5P.{{sfn|Swanborough|Bowers|1976|pp=42β43}} The Coast Guard retired its JRBs in 1956 and sold most of them as surplus in 1959, but one was retained by the [[United States Coast Guard Reserve]] until at least 1972.<ref name=uscg/><ref name=Baugher_cg/> With the adoption of the [[1962 United States Tri-Service aircraft designation system]], the Navy's SNB-5 and SNB-5P became the TC-45J and RC-45J respectively, later becoming the UC-45J as their primary mission shifted from aircrew training to utility transport work.{{sfn|Swanborough|Bowers|1976|p=43}} The C-45 flew in USAF service until 1963, the USN retired its last UC-45J in 1972, while the U.S. Army flew its C-45s until 1976. In later years, the military called these aircraft "bug smashers" in reference to their extensive use supplying mandatory flight hours for desk-bound aviators in the Pentagon.<ref name="Proceedings">O'Rourke, G.G, CAPT USN. "Of Hosenoses, Stoofs, and Lefthanded Spads." ''United States Naval Institute Proceedings'', July 1968.</ref> Beech 18s were used extensively by [[Air America (airline)|Air America]] during the [[Vietnam War]]; initially more-or-less standard ex-military C-45 examples were used, but then the airline had 12 aircraft modified by Conrad Conversions in 1963 and 1964 to increase performance and load-carrying capacity. The modified aircraft were known as Conrad Ten-Twos, as the maximum takeoff weight (MTOW) was increased to {{convert|10200|lb|abbr=on}}.<ref name="AA"/><ref>Deakin, John. [http://www.avweb.com/news/pelican/186015-1.html "Pelican's Perch #75:Those Dreadful POHs (Part 1)".] ''AVweb'', November 9, 2003. Retrieved: August 12, 2008.</ref> The increase was achieved by several airframe modifications, including increased horizontal stabilizer angle-of-incidence, redesigned undercarriage doors, and aerodynamically improved wingtips. Air America then had Volpar convert 14 aircraft to [[turboprop]] power, fitted with [[Garrett AiResearch TPE-331]] engines; modified aircraft were called Volpar Turbo Beeches, and also had a further increase in MTOW to {{convert|10286|lb|abbr=on}}.<ref name="AA">[https://www.utdallas.edu/library/specialcollections/hac/cataam/Leeker/aircraft/vtb.pdf "Air America: Beech/Volpar Turbo Beech 18".] ''University of Texas at Dallas'', 2006. Retrieved: August 5, 2017.</ref> ===Spar problems=== The [[wing spar]] of the Model 18 was fabricated by welding an assembly of tubular steel. The configuration of the tubes in combination with drilled holes from aftermarket [[Supplemental Type Certificate|STC]] modifications on some of these aircraft have allowed the spar to become susceptible to corrosion and cracking while in service.<ref>Ramey, Taigh. [http://www.twinbeech.com/beech18sparconcerns.htm "Spar concerns."] Twinbeech.com. Retrieved: December 17, 2014.</ref> This prompted the FAA to issue an [[Airworthiness Directive]] in 1975, mandating the fitting of a spar strap to some Model 18s. This led, in turn, to the retirement of a large number of STC-modified Model 18s when owners determined the aircraft were worth less than the cost of the modifications. The corrosion on unmodified spars was not a problem; it occurred due to the additional exposed surface area created through the STC hole-drilling process. Further requirements have been mandated by the FAA and other national airworthiness authorities, including regular removal of the spar strap to allow the strap to be checked for cracks and corrosion and the spar to be [[Industrial radiography|X-rayed]]. In Australia, the airworthiness authority has placed a life limit on the airframe, beyond which aircraft are not allowed to fly.<ref>Ramey, Taigh. [http://www.twinbeech.com/considerations_when_buying_a_twi.htm "Vintage Aircraft: Things to Consider when Buying a Twin Beech Project."] ''Twinbeech.com'', Stockton, California. Retrieved: August 24, 2008.</ref><ref>[http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/0EA4F6AC8BB1222986256A46004B8A4E?OpenDocument "FAA Airworthiness Directive No. AD 75-27-09."] ''Federal Aviation Administration''. Retrieved: August 24, 2008</ref><ref>[http://www.casa.gov.au/airworth/airwd/ADfiles/under/beech18/BEECH18-017.pdf "CASA Airworthiness Directive No. AD/BEECH 18/17."] {{webarchive|url=https://web.archive.org/web/20080801104732/http://www.casa.gov.au/airworth/airwd/ADfiles/under/beech18/BEECH18-017.pdf |date=2008-08-01 }} ''CASA.'' Retrieved: August 24, 2008.</ref> Summary: Please note that all contributions to Christianpedia may be edited, altered, or removed by other contributors. If you do not want your writing to be edited mercilessly, then do not submit it here. You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource (see Christianpedia:Copyrights for details). Do not submit copyrighted work without permission! Cancel Editing help (opens in new window) Discuss this page