The Potez Po-633B2 light bomber / reconnaissance
In 1934, the French Air Ministry decided to boost the capabilities
of the L'Armee de l'air by providing it with a "workhorse"
capable of performing all sort of missions. Therefore, they issued a
specification for a twin-engine, multi-role plane, to be powered by
two small-diameter radial engines conceived and built by Gnome-Rhône
and Hispano-Suiza. The plane had to have good armament, to be able to
act as a kind of airborne controller for single-seat fighters, to serve
as interceptor, heavy fighter and night fighter as well.
A team of engineers from the Potez company, headed by Louis
and M.Delaruelle, came up with the Potez 63 design. It was a cantilever,
low-wing monoplane of basically stressed-skin light alloy construction
with an oval-shaped fuselage made up of three sections (semi-monocoque
nose and tail sections attached to a four-longeron central section).
It had a low-set wing, with a flat constant-chord center section built
integrally with the
central part and external panels tapered in thickness and chord. Cockpit
was a raised, "glasshouse" type, with sliding panels for easier
access. The landing gear was fully retractable, with the main gear retracting
rearwards into the undersides of the wing.
First prototype, designated Po-63.01, took off for the first
time in April 1936, with a temporary wooden tail, so that it could be
easily transformed into the optimal shape. It was powered by two Hispano-Suiza
14Hbs radial engines. After some time, a second prototype, designated
as Po-631.01, was completed and started test flights. This plane was
powered by two Gnome-Rhone 14Mars engines. After the Po-631.01 was built,
the Po-63.01 became the Po-630.01.
After beating its rivals ( the Breguet Bre.690, the Hanriot H.220, Loire - Nieuport LN.20 and Romano R-110 ) in an open contest, the Po-63 managed to make such an impression on the French Air Ministry, that it was quick decided to place an order for a batch of no less than 7 pre-production Po-63 variants.
Eventually, 5 of these versions entered mass-production
: - Potez Po-630C.3, a three-seat fighter powered by 2 Hispano-Suiza 14AB-02/03
or -10/11 radial, rated at 650 hp or 700 hp engines and armed with two
fixed forward-firing 20 mm cannons plus a rear-firing 7.5 MAC machine
gun ( initially was destined for night fighter units, but some planes
were sent to single-seat fighter units to act as avions de commandement,
meaning command aircraft for single-seat fighters ) ; Potez Po-631C.3,
a dedicated three-seat fighter, powered by 2 Gnome-Rhône 14M-4/5
or -6/7 radial, with the same armament ; Potez Po-633B.2, a light bomber,
pretty much similar to the 631C.3, but with a glazed lower nose where
the bombardier stood , and an internal bomb bay where eight 50 kg bombs
positioned vertically could be carried ; Potez Po-637A.3, a three-seat
reconnaissance and army co-operation version, fitted with a glazed observation
gondola and a Labrely F.20, F.30 or F.50 camera with up to 40 marker flares
in the rear furselage, as well as two 50 kg bombs underneath the wings
; Potez Po-63.11A.3, the final army co-operation and reconnaissance version.
The ARR became interested by the Po-633B2 in 1937, and in the
spring of 1938 an order for 20 modified planes was placed. Changes consisted
in fitting electrically operated Ratier propellers, inertia engine starters,
and provision for a Labrely F.30 or F.50 reconnaissance camera in the
weapons bay. Defensive armament was changed as well : 3 Browning FN 7.92
mm machine guns were mounted, one fixed forward-firing, one
rearward-firing in the rear cockpit and one rearward-firing in a new ventral
hatch position. In 1939, all 20 Po-633B2's arrived in Romania, where they
were assigned to the 74th and 75th Bomber Squadrons of the 2nd Bomber
Group. Afterwards, 20 more airplanes were ordered but it seems that only
1 was delivered, as the rest were embargoed by the French, and pressed
into service with their own air force.
At the start of operation Barbarossa, 17 Po-633B2 were standing
by ready for action. They did a pretty good job, but took heavy losses
from AA fire, so after just one month the 75th Bomber Squadron handed
in all its remaining planes to the 74th Squadron. After participating
in the siege of Odessa, the 74th had been reduced to 5 operational Po-633B2's.
In late 1941, 9 more Po-633's were received from Vichy France in exchange
for various oil products. Most were assigned to the 74th Bomber Squadron ( they had 9 Po-633's when they were sent to the east front )
but it seems that some were given to the 3rd Long Range Recon Squadron
as well. Both units took part in the Stalingrad campaign, but were pulled
out of action and sent home by early 1943. Afterwards, surviving aircraft
were used as trainers for night fighter pilots. Generally, the Po-633's
achieved a good combat reputation, mainly for its good handling and good
survivability, being able to take considerable damage and still make it