class were available. Additionally, two-stroke engines are very smooth running at high RPM, but have real problems running smoothly at low RPM. Even after months of effort, the Hirth designs showed rough running and high minimum power outputs when idled. Two-strokes also have high fuel consumption, and it was expected that the larger engines would burn between 4.5 and 5.5 gallons per hour. By this point, it seemed the basic design was complete, and Bede turned his attention to other projects. One was the jet-powered BD-5J, which boosted performance to . There was an attempt to sidestep the engine problem with the BD-5S glider (S for Sailplane), with lengthened wings and no engine, which prompted Air Progress magazine to sarcastically note, "At last, a BD-5 with no engine problems." This glider version did not fly well and the project was scrapped. Some work on a BD-6 was also carried out, essentially a downsized BD-4 single-seater. There was some criticism that Bede should have attended to the basic BD-5 rather than move on to these other projects. Bede also decided to seek FAA certification of the BD-5D as a production aircraft and sell it complete, and began taking $600 deposits for this model. Deliveries begin By the middle of 1973 the basic design was complete and the tooling set up for production. Now over two and a half years after the deposits started being taken, the engines were the only part holding up deliveries, so Bede offered to ship the kit with the engine to follow. This was a fairly attractive option; it meant the builder could get to work and hopefully complete the airframe by the time the engine arrived, at that point expected in September 1973. Many builders took the company up on the offer, only to receive incomplete kits and plans. Initially, all three Hirth engines were offered; builders could keep the 40 hp engine, or "trade up" to 55 hp or . The latter, which Bede had developed with Hirth, was now considered the baseline engine for the aircraft; when equipped with the original 40 hp the aircraft proved to be underpowered. In a late 1973 newsletter to prospective owners, Bede suggested the 70 hp model and discouraged use of the smaller engines. Prices had risen throughout the 30 months since deposits were first taken. Originally priced at $1,799, the base price was raised to $2,599 with