For reference purposes I’ve collated a list of production batch numbers for the CAC Wirraway aircraft delivered to the RAAF between July 1939 and July 1946. This page contains the batch numbers for Mark III Wirraways, which were delivered under the CA-16 production “contract”. A summary of Mark III production is given in the table below:

Wirraway type	CAC Contract Number	RAAF Contract Demand	Ordering entity	Order Number	Quantity delivered	CAC Constructor’s Numbers	RAAF Serials
Mk III	CA-16	D.A.P. 1007	DAP	C.S.1800	135	1075 to 1209	A20-623 to 757

DAP = Department of Aircraft Production

Batch numbers
Wirraway Mark III production was planned in batches of 11 aircraft. But there was one exception:

• The final batch of production, batch “N” consisted of only 3 aircraft to make up 135 aircraft

Batch numbers consisted of a letter for each batch followed by a number for each aircraft in that batch (e.g. A1, A2, A3, A4, etc)..The letters I, O, Q and V were generally not used as batch numbers, as they could be confused for numbers. The CA-16 contract started with batch “A”.

The definitive source for batch numbers is a ledger book kept by Mr Gordon Parker, Supervisor in the Sales Department, and one of CAC’s earliest employees from 1936. This book is now held in the collection of the Australian National Aviation Museum at Moorabbin Airport.

Unfortunately there are two discrepancies in the last 25 entries in the ledger. Firstly, Parker skipped batch “L” for A20-733 to A20-743 and went straight from “K” to “M”. We know that batch “L” was not skipped in reality, as two surviving data plates reclaimed from airframes at Tocumwal show L2 for A20-734 (c/n 1186) and M5 for A20-748 (c/n 1200). Secondly, Parker stopped recording batch numbers at A20-740, so the batch codes shown in the list below are “extrapolated”. The batch “M” extrapolation is supported by the evidence of the M5 batch number on the A20-748 data plate. This leaves a question as to the last three aircraft – were they N1, N2 and N3, or was batch M continued for three more aircraft, as M12, M13 and M14. I have postulated that a new batch “N” was commenced, since CAC did not expect to end production at 755 aircraft. There were many debates between CAC and DAP over how many aircraft to supply to the RAAF (the original order was for 150 aircraft, and another order had been received for 100 additional “Dive Bomber” aircraft planned as CA-20, but only 135 were delivered under the CA-16 order), so it is logical to presume that the last three aircraft were N1, N2 and N3.

During production, batch numbers were temporarily attached to the firewall and then the rudder (once the engine was mounted). These temporary numbers are sometimes visible in factory photos.

Constructor’s numbers
These were a sequence of numbers allocated to each aircraft in the sequence that they came off the line. Wirraways delivered under the CA-16 contract were given constructor’s numbers from 1075 to 1209.

RAAF stores number
All equipment in the RAAF was allocated a stores number for tracking and accounting purposes. Aircraft were tracked under the category “A” and each aircraft was given a specific number, Wirraway aircraft being allocated the category A20. These numbers are often referred to as the “serial number” of the aircraft in RAAF service.

Linking batch numbers, stores numbers and constructor’s numbers
Here are several photos showing Mark III Wirraways under construction, allowing us to link the batch codes to RAAF stores/serial numbers.

Below we can see a group of camouflaged Mark III Wirraways on the production line. Batch numbers visible include D10 (furthest away, on the left) and E1 to E5 (closest, on the right). In the original photograph, D11 is also visible, sitting between D10 and E1, but pointing tail-on to the camera, so its rudder cannot be seen. These aircraft are A20-665 to A20-671, as evidenced by the three-digit number after the two-digit batch codes. 

Later in the CA-16 contract, below is a view of H8 (A20-707, c/n 1159) attached to the lifting sling. The batch label taped to the rudder showing H8-707 is repeated in the inset at lower right.

The photo below shows late CA-16 production, with the aircraft now painted overall Trainer Yellow.  K7 (A20-728) is visible sitting on dolly wheels, and the rudder of K8 (A20-729) is visible behind the aircraft (shown enlarged in the inset at lower left).

The table below lists batch numbers and construction numbers for all Mark III Wirraway aircraft, delivered under the CA-16 contract. The batch numbers are transcribed from Gordon Parker’s delivery records (with the last 25 entries corrected), and have been cross-checked with photographic evidence (some of which is shown above) and several frames and ID tags held in museums or private collections.

CAC Contract Number CA-	CAC Constructor’s Number	RAAF Serial	Batch Number
16	1075	A20-623	A1
16	1076	A20-624	A2
16	1077	A20-625	A3
16	1078	A20-626	A4
16	1079	A20-627	A5
16	1080	A20-628	A6
16	1081	A20-629	A7
16	1082	A20-630	A8
16	1083	A20-631	A9
16	1084	A20-632	A10
16	1085	A20-633	A11
16	1086	A20-634	B1
16	1087	A20-635	B2
16	1088	A20-636	B3
16	1089	A20-637	B4
16	1090	A20-638	B5
16	1091	A20-639	B6
16	1092	A20-640	B7
16	1093	A20-641	B8
16	1094	A20-642	B9
16	1095	A20-643	B10
16	1096	A20-644	B11
16	1097	A20-645	C1
16	1098	A20-646	C2
16	1099	A20-647	C3
16	1100	A20-648	C4
16	1101	A20-649	C5
16	1102	A20-650	C6
16	1103	A20-651	C7
16	1104	A20-652	C8
16	1105	A20-653	C9
16	1106	A20-654	C10
16	1107	A20-655	C11
16	1108	A20-656	D1
16	1109	A20-657	D2
16	1110	A20-658	D3
16	1111	A20-659	D4
16	1112	A20-660	D5
16	1113	A20-661	D6
16	1114	A20-662	D7
16	1115	A20-663	D8
16	1116	A20-664	D9
16	1117	A20-665	D10
16	1118	A20-666	D11
16	1119	A20-667	E1
16	1120	A20-668	E2
16	1121	A20-669	E3
16	1122	A20-670	E4
16	1123	A20-671	E5
16	1124	A20-672	E6
16	1125	A20-673	E7
16	1126	A20-674	E8
16	1127	A20-675	E9
16	1128	A20-676	E10
16	1129	A20-677	E11
16	1130	A20-678	F1
16	1131	A20-679	F2
16	1132	A20-680	F3
16	1133	A20-681	F4
16	1134	A20-682	F5
16	1135	A20-683	F6
16	1136	A20-684	F7
16	1137	A20-685	F8
16	1138	A20-686	F9
16	1139	A20-687	F10
16	1140	A20-688	F11
16	1141	A20-689	G1
16	1142	A20-690	G2
16	1143	A20-691	G3
16	1144	A20-692	G4
16	1145	A20-693	G5
16	1146	A20-694	G6
16	1147	A20-695	G7
16	1148	A20-696	G8
16	1149	A20-697	G9
16	1150	A20-698	G10
16	1151	A20-699	G11
16	1152	A20-700	H1
16	1153	A20-701	H2
16	1154	A20-702	H3
16	1155	A20-703	H4
16	1156	A20-704	H5
16	1157	A20-705	H6
16	1158	A20-706	H7
16	1159	A20-707	H8
16	1160	A20-708	H9
16	1161	A20-709	H10
16	1162	A20-710	H11
16	1163	A20-711	J1
16	1164	A20-712	J2
16	1165	A20-713	J3
16	1166	A20-714	J4
16	1167	A20-715	J5
16	1168	A20-716	J6
16	1169	A20-717	J7
16	1170	A20-718	J8
16	1171	A20-719	J9
16	1172	A20-720	J10
16	1173	A20-721	J11
16	1174	A20-722	K1
16	1175	A20-723	K2
16	1176	A20-724	K3
16	1177	A20-725	K4
16	1178	A20-726	K5
16	1179	A20-727	K6
16	1180	A20-728	K7
16	1181	A20-729	K8
16	1182	A20-730	K9
16	1183	A20-731	K10
16	1184	A20-732	K11
16	1185	A20-733	L1
16	1186	A20-734	L2
16	1187	A20-735	L3
16	1188	A20-736	L4
16	1189	A20-737	L5
16	1190	A20-738	L6
16	1191	A20-739	L7
16	1192	A20-740	L8
16	1193	A20-741	L9
16	1194	A20-742	L10
16	1195	A20-743	L11
16	1196	A20-744	M1
16	1197	A20-745	M2
16	1198	A20-746	M3
16	1199	A20-747	M4
16	1200	A20-748	M5
16	1201	A20-749	M6
16	1202	A20-750	M7
16	1203	A20-751	M8
16	1204	A20-752	M9
16	1205	A20-753	M10
16	1206	A20-754	M11
16	1207	A20-755	N1
16	1208	A20-756	N2
16	1209	A20-757	N3

I welcome feedback on the table above, with supporting evidence of any possible inaccuracies.

References:

Commonwealth Aircraft Corporation. Sales Department Aircraft Delivery Ledger; Kept by Gordon Parker. CAC Collection, Australian National Aviation Museum.

Commonwealth Aircraft Corporation. Aircraft Drawing Office Manual. Incorporating up to Amendment List No. 2, Melbourne, Australia, 1946.