D1 single seater

D1 specifications

A pilot report about the D1


When appearances are deceptive

D1 specifications

Do you remember the Mini Cooper? It looked like you could hardly fit in but once inside it appeared to be one of the roomiest cars on the marked.

Likewise with the D1,
Looks small but has the widest cockpit of all light aircraft
Looks nervous in flight but is in fact very stable
Looks only suitable for flights around the airfield but is in fact a very comfortable traveling aircraft
Looks if no luggage can be carried but has 500 ltr for this
Looks tricky to land with the monowheel but is very stable on the ground
Looks fast but is fast.

The D1 is not weird just to be weird, in many aspects it is a better aircraft like in stability, reaction to turbulence, inner space and flight comfort.

All parts are designed for the best solution.

Therefore the landing gear is of a monowheel type which is lighter and less complex and gives aileron control before liftoff, so no surprises with crosswind. This monowheel is retractable and steering to prevent groundloops.

The wings have only 2 elevons, so aileron and elevator mixed which is not so complicated as it looks, only 2 steering rods go directly from the stick to the elevon.

The outerwings can be folded upward by only pulling out 1 pin, no fairings removed or controls disconnected. Folding out and pulling the aircraft from the trailer only takes 15 minutes.
This can save you a lot of money for hangarage.

The tanks are simple plastic jerrycans, the remaining fuel quantity can be read directly.

Flying the Verhees Delta

Flying is like with any other aircraft, however the rudder is only used for engine torque compensation, not in turns.
In turbulence and thermals the Delta is much better than normal light aircraft. When an upgust is entered the nose is automatically lowered a bit and the aircraft will not endure much more than the +1 g it already had. This gives a very comfortable ride even in turbulence. The effect has been calculated and is also there in practice.

Just keep directional control with the rudder and keep wings level with the ailerons but this is not critical. When liftoff speed is reached the Delta will automatically get airborne without pitch change. When positive climb is there the wheel can be retracted for better climb performance. This is done quickly by hand lever so that the better climbing is there right away.

Landing: The Delta has a fixed relation between elevator position and speed, independent of power setting and not influenced by the airflow from the wing like with a normal aircraft. So simply fly to the runway with the right elevator position and round out a few meters above the runway. Too high is not a problem, the Delta will not sink too rapidly.
Crosswind landings are easy, there is little need for rudder although it will save the tires. The steering mainwheel will line-up itself, no danger of groundloop. The only tricky point is the touchdown speed, this must be so slow that the tailwheel touches first.

At about 30 deg angle of attack there is a strong buffeting. If the elevator is pulled through there is a wingdip which can be counteracted by the ailerons, in the landing you won’t be doing this because the forward visibility is zero.. It is possible to limit the elevator travel, then the wingdip will not occur.

Most aircraft suffer from additional drag due to the propellerwind. This causes the fuselage to actually fly faster through the surrounding air.

With the Delta this propellerwind creates lift so that the induced drag will be less. So where traction propellers have less efficiency with other aircraft it gives benefit with the Delta.