The BM-4000, actually a B-4000 whose front cockpit was converted to a cargo hold, served with some airlines as a quick carrier for lighter, frequently-scheduled loads. Powered by a Wright J5 220 hp engine, the B-4000 was built in 1929 and enjoyed a production run of 20 examples. Its construction was of fabric over steel tubing. Length: 23'4". Wingspan (upper): 33'0". Maximum speed: 128 mph.