The Republic Aviation P-47 “Thunderbolt” entered service in May 1942 with the introduction of the P-47B. It had a “Razorback”, a high dorsal spine behind the side-ways opening canopy that reduced visibility. As improvements were made a “D” variant was produced with 12,602 being manufactured. The British developed a sliding bubble canopy for their Typhoon and this was adopted by the USAAF starting with the P-47D-5. With its ability to survive enemy fire along with impressive armament and bomb load the P-47 excelled at ground attack roles.