The Queen Air was the first type of Beechcraft’s very successful twin prop series, that later developed in the King Air. It is a low wing, low horizontal stabiliser aircraft, with two piston or turboprop engines and a main landing gear that retracts forward into the nacelles. The single wheel nose gear retracts rearward. While at first rectangular, almost square cabin windows were used, most versions have the round cabin windows that are still used on the King Airs that roll off the production line today. The same applies to the characteristic cockpit windows, with the typical triangular and D-shaped side windows.

Later also King Air versions with a T-tail started to be made, but these are described separately.

The different versions of the Beech Queen Air and low tail King Air can be distinguished by:

• the shape of the vertical stabiliser
• the shape of the last cockpit side window
• the shape of the engine nacelles
• the number of propeller blades
• the location of the pitot tubes
• the size of the wing tips
• the presence of pods at the wing tips
• the number and shape of cabin windows
• the number, shape and location of antennas
• the shape of the tail cone

The Beech 65 Queen Air was developed from the Beech 50 Twin Bonanza, with a larger cabin featuring three square cabin windows. It does not have a D-shaped cockpit side window yet, but a rectangular one. The original Beech 65 has a straight vertical tail with small, curved dorsal fin. The Queen Air has piston engines in rather thick nacelles, which have a half ring (oval) shaped cooler intake at the front.

The US Army designation was L-23F Seminole, and U-8F after 1962.

The Beech 80 was first introduced after the Beech 65, and is basically a 65 with a swept vertical tail and more powerfull engines. The Beech A65 is externally similar, but has the engines of the 65. The Beech A65 is supposed to have a fourth square starboard cabin window, across the cabin door. However, there are certainly examples without (see photo below).

The Beech A80 - first introduced - has a nearly 1.3 metre wider wing span than the Beech 80, and a re-designed nose. The model B80 has an increased take-off weight, but is externally the same. The same applies to the B80A, which had lower power engines. The Beech 70 has the lower power engines of the Beech A65 and the increased wing span of the Beech A80, but is also externally very similar.

On this photo of a Beech B80 the wider distance between aileron and wingtip is slightly better visible. (photo: Michel Gilliand/WikiMedia)

This version can be recognised easily, as it has the round windows and D-shaped cockpit side windows of a Beech 90 King Air with the piston engines of the Beech B80. The model A88 was a test aircraft with higher power engines, and for the rest the same as the standard 88.

The Beech 88 has the round cabin windows of the King Air, but is for the rest a piston powered Queen Air. (photo: RuthAS/WikiMedia)

The Beech 87, also designated NU-8F, was a proof of concept for the U-21 military transport and for the later King Air series. It was a modified Beech A80 with PT6A turboprop engines. It also has a left hinged door left of the main cabin door, leaving room for only two square cabin windows. Eventually Beechcraft decided to give the U-21 the model name Beech 65-A90-1, even though it has square cabin windows due to the unpressurised cabin. The utility transport versions have US Army designation U-21A, GU-21A (for a ground trainer) and JU-21A (special test aircraft). Some U‑21As were converted to electronic reconnaissance aircraft with many antennas on wings and fuselage, receiving a different designation (see below).

EU-21A was the designation for an electronic relay version of the U-21A. Compared to the standard U-21A it has long antennas straight up and down from the outer wings.

Another Beechcraft 65-A90-1, but a U-21A converted to a special electronics mission aircraft. Most equipment and antennas are in wingtip pods (looking like tip tanks). There are also four short blade antennas on top of the fuselage, of which two near the dorsal fin. The RU-21 variant is also referred to as "Cefirm Leader".

The RU-21D also is a electronic reconnaisance versions of the Beechcraft 65-A90-1. The antenna configuration seems to differ, but the likely one has single long antennas up and down from the wings near the tips and nacelles, and from the horizontal stabilisers. It is sometimes referred to as "Laffing Eagle".

Even though the U-21G has officially the same Beechcraft model designation (65-A90-1) as the (E)U-21A, it looks different, because it has round cabin windows. On the left side there is more space between the second and third cabin window, with the third window in the cargo door. Note that some U-21Gs seem to have square cabin windows. Possibly they were originally delivered as such, and later converted with round windows. At least some examples that eventually ended up at the civil market were converted with round windows.

This specialised electronic surveillance version of U-21A is unlike most others, because it has twin wheels on the main landing gear, and longer main landing gear doors. The RU-21B "Cefirm Leader" has three wide blade antennas on top of the fuselage, and one below the fuselage near the cabin door. It has just one square cabin window, on the right side only.

Like the RU-21B the RU-21C has two wheels on each main landing gear. It has fewer antennas though, two blade antennas on top of the fuselage and none at the bottom. The RU-21C is called "Cefirm Leader" like the previous versions.

This version of the RU-21 has single wheel main landing gears again. The antenna arrangement is as follows: double long blade antennas up and down the wings near the tips, single long ones near the nacelles, two long and two short ones on top of the fuselage and one long one at the bottom. It has cabin windows like the U-21A.

On the final RU-21 version most antennas have been relocated to pods at the lengthened wing tips (like tip tanks). Long blade antennas remain near the nacelles. Also the RU-21H has no cabin windows on the left side but one on the right side, although that may vary on specific aircraft. The RU-21H is named "Guard Rail".

The King Air is very basically a Queen Air with turboprop engines, so the general arrangement is the same. The basic Beech 90 is based on the Beech 87 concept aircraft, but then with a pressu­rised cabin, D-shaped last cockpit side window and round cabin windows. The Beech A90 has different PT6A turboprop engines, improved engine de-icing and a redesigned cockpit, but this is not visible on the outside. Both subtypes have in common standard three cabin windows next to each other, a small distance between the ailerons and wing tips, a pitot tube underneath the left wing and a short, blunt tail cone.

The King Air B90 version is a King Air A90 with wing span increased by 1.5 metres, leading to a visibly larger distance between the ailerons and wing tips. Furthermore it has an optional (fourth) cabin window on the right side, and a longer tail cone. It retains the pitot tube under the wing's leading edges.

One Beech B90 was delivered to the USAF as VC-6A for VIP transport.

This is a Beech B90 with the pressurisation and cabin environment systems of the Beech 100. During the long production run of this model the pitot tubes were relocated from below the leading edge of the wings to both sides of the nose. Hence you cannot easily distinguish the C90 from either the B90 nor C90-1.

The USAF version of the Beech C90 was designated VC-6B. The US Navy received a training version of the King Air C90, designated as T-44A Pegasus. It has better engines than that model. Beechcraft officially called this a model H90.

The T-44A US Navy training version of the King Air is externally the same as the Beech C90. (photo: Mike Freer - Touchdown Aviation)

To improve engine efficiency, the air intakes of the Beech C90 were lengthened, creating the Beech C90A. To make it more difficult for us, Raisbeck can convert older King Airs with these ‘ram-air recovery' or 'pitot-style' intakes as well. The same applies to earlier Taurus 90 conversions by Swearingen. Other changes include an improved gear retraction system and the King Air F90-1’s pressurisation/heating system.

The Japanese navy acquired this version (and the King Air C90) for training. It is designated LC-90, TC-90 and UC-90 by them.

The King Air C90SE is the 'poor man’s' version of the Beech C90B with three-bladed props and “mechanical” instruments.

This is basically a King Air C90 with the more powerful engines of the Beech 100. These engines have slightly larger exhausts, and no cooler exhaust at the side. It was also the first King Air with pitot tubes under the nose. Also the landing lights are no longer in the wing leading edge. That was then copied to subsequent King Air C90s (or modified on older examples). Some sources state that it has a redesigned tailplane or wings. In any case, we do not see the difference with the Beech C90.

The Power 90 is another engine upgrade for the King Air, but only for the older versions 90, A90, B90 and C90. The engine used is a Walter M601, driving five blade propellers. They have exhausts at the side of the nacelles, slightly wider in diameter and turned up.

Swearingen (and later Excalibur Aviation) offered the Queen Air 800 conversion of the Beech 65 (including L-23/U-8) with different piston engines (both rated 400 hp, hence Queen Air 800), which can be seen by looking at the front of the engine cowlings, which are much flatter. Also, the longer gear doors fully enclose the gear when retracted.

This is a similar conversion as the Queen Air 800, but then of the Beech 80, A80 and B80. The Queen Air 8800 has different piston engines, which can be seen by looking at the front of the engine cowlings, which are much flatter. The main gear doors are longer as well.