The type is a derivative of the HM14 flying-flea concept, using the same biplane / taildragger construction (although a much more conventional aerofoil section than the HM14). Pitch control was through movement of the forward (upper) wing, there was no movement of the rear (lower) wing, and there was no primary roll control.Directional control was via the large rudder, which was controlled by the stick, which also controlled the steerable tailwheel. Foot brakes (one per side), augmented steering, although were primarily used for normal stopping. This aircraft was also modified with separate rudder pedals, which the owner said he used for steering hands-off in the cruise, but are not a standard fitment on the type, and were not used during this flight.A bungee, secured near to the firewall, and slid up or down the stick provided a limited pitch trimmer.Visibility was poor to the front, typical of many open cockpit taildraggers, but excellent to the sides and behind – it was very easy to turn around and see the fin. Forward view was mainly obstructed by the high nose, but also by the forward wing, which blocked the view fwds/up.The aircraft was powered by a Rotax 503-2V engine (generates about 50hp). Other instrumentation were a pitot ASI (kph, pitot mounted on the movable upper wing), altimeter (metres, static source not known but suspected within the cockpit), dual CHT gauges (°C), RPM gauge, and hobbs meter.

Taxiing was done controlling the aircraft with stick (for directional control) and throttle. The brakes were effective, but only really for stopping, they didn’t help the turning much, but this wasn’t needed. Even on quite rough or sloping ground, very precise control was possible, although the pilot had to keep looking out to one side or the other – seeing over the nose wasn’t possible. Due to the narrow fuselage and wearing of a full face helmet, this wasn’t a particular problem.

Take-off was flown in the conventional taildragger manner, holding the stick forward until the tail lifted (which was quite a marked, probably about 15-20° attitude change), the stick was then checked back to central, and the aircraft naturally flew off, establishing quickly at a good (not measured, but estimated at better than 500fpm) climb rate at an indicated airspeed of 80kph.During the initial climb-out, the aircraft suffered a number of 20-30° rolling departures. This was probably mainly due to the known problem of rotor over Rwy 21 at Popham, but the risk of rolling PIO had been warned, and the briefed solution, establishing a gentle turn with the stick to either side, worked quickly to prevent any recurrence.The aircraft wanted to trim at about 110 kph, and a constant back-pressure on the stick of around 2daN was needed to maintain the briefed climb speed of 80 kph.

Various stability modes were investigated.The SPO was deadbeat when excited using a pitch doublet. The Phugoid however was lightly damped, having a period of about 20 second, and reducing in amplitude by an estimated 75% per cycle. However, it could be damped out easily using the pitch control, and wasn’t particularly intrusive on cruising flight.At any speed above 100 kph, a neutrally stable Dutch Roll (yaw:roll ratio around 2:1) started to intrude into the flying task, and above 120kph it was quite annoying. However, in the cruise at about 90 kph, this went away completely, and it could reasonably be argued that the DR tends to provide good clear warning that the aircraft was being flown at high speeds, above those sensibly useable for the cruise.

LSS was very firm, with about 2daN / 100mm of stick movement being needed for a 20kph speed change. This gave good feedback and feel, and speed control could be maintained very easily.Roll control was excellent, with a roll rate of about 30°/s being achievable with about half lateral stick, and roll mode time constant being so short as almost indistinguishable.

60° bank / 2g turns were flown to both left and right. These were flown with the stick, using a slight forward pressure to maintain speed. Lateral displacement was small, but force was enough to ensure good firm handling. The aircraft became very steady, with none of the previously noted DR being at-all apparent.

In summary, stability and control of the HM293 was excellent and although the DR could become intrusive at high speeds, and a conscious effort was needed to damp the Phugoid, both could reasonably be dealt with, without significant effort, by a pilot of moderate ability.

QTY 3 stalls were flown at idle, 1kn/s-ish, (one with wings level, one each 30 banked) in each case the aircraft stalled with the ASI off the bottom of the dial (lowest reading possible was 30kph), presumably because the pitot with full back-stick was very steeply nose-up, being attached to the forward (control) wing. The stall attitude was very steeply nose up (about 15° above the normal flight attitude), with warning provided by light stick buffet about 5° attitude below the stall, and the stick position (nearly fully back) and the attitude. Stall was marked by a firm but undramatic nose-down pitching motion through about 20°, but no wing drop.

An overhead join was flown at Popham, giving a further opportunity to look at height and flightpath control, both were very good, and visibility within the circuit (except for ahead and up/down) was adequate. An approach was flown at about 95 kph (higher than the recommended 80 kph due to the significant rotor on the runway in question, but still requiring moderate back-pressure on the stick). The flightpath could be held accurately, and there is no doubt that accurate approach speed and touchdown point can reasonably be maintained.It was noted that ASI readings varied a great deal as the pitch control was moved. This is attributed to the pitot being located on the movable forward wing, and could present problems if trying to make significant attitude changes (such as during a go-around) and it is felt that consideration should be given to relocating the Pitot head into a more stable position (highly desirable).A conventional 3-wheel taildragger landing was carried out, with the stick about 2/3 back from the neutral position. After touchdown, the aircraft slewed about 80° to the left in a groundloop. This was attributed to the pilot, being more used to conventional taildraggers, holding the stick central with the expectation of using his feet to keep the aircraft straight, undoubtedly the stick should have been used much more on the ground to keep the aircraft straight. This is an aspect of the aircraft which some attention should be given to in the POH, but was far more a failing of the pilot than of the aeroplane.

The HM293 was a pleasant and responsive aircraft to fly, with characteristics that were unconventional but could not be considered unacceptable.

The aircraft might be improved if the airspeed at which DR onsets could be increased by perhaps 30 kph, and if the Phugoid mode could be made better damped, but neither of these are major concerns.

The only major aspect of the aircraft which was considered poor was the pitch trimmer, which did not allow the aircraft to be trimmed at sensible climb, cruise or approach speeds.