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 D-Plane,
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 D-Plane 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.

Read the flight report (by Peter Kuypers)

A tour around the Baltic (journey report)

List of journeys

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 D-Plane

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.

with the Delta there is 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 that makes that the fuselage is actually flying 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.


Wingspan: 4,5 m
Length with Subaru engine: 3,3 m
Wing area: 10 m2

Empty weight prototype: 210 kg
Max take-off weight: 340 kg

Cruise speed: 220 km/h
Vne: 270 km/h
Stallspeed: 85 km/h

Loadfacto:r +/- 6g

Tank content: 60 ltrs

Engine on prototype Subaru EA 71, 1600 cc, 50 HP in direct drive, liquid cooled
uses 13 l/hr mogas at cruisespeed

Propeller on prototype 138×110 cm wood, fixed pitch

Construction all metal, mainstructure aluminum 6061 or 2024

Landinggear steering monowheel type with rubber compression spring
tailwheel with shock cord suspension
tipwheels with metal torsion spring suspension

Suitable engines:

The prototype is fitted with a 1600 cc Subaru EA 71 engine, propeller directly fitted to the crankshaft. The engine is lightened, all redundant aluminum is milled from the housing and the steel oilpan is replaced by an aluminum one.
The cooler is placed in the starboard wing.

Other engines that will do the job are the 1800 cc VW and the 80 HP Jabiru although this one would not fit in as nicely as the other ones.

You can also install a 2 stroke like the Rotax 582 but the fuel consumption will be more.



For tools you only need the normal tools for aluminum like an electric nibbler (or plasma cutter)
Pneumatic riveting hammer etc. A folding bench can be home made of hardwood.
Because of the metal construction you do not need a workshop with climate control.

There is minimum of milling and welding involved which can be done by a friend with the right equipment and skills if you can’t do it yourself.

Plans will come as printed CAD drawings with builders handbook and digital cuttingfiles.

set of plans and builders guide: 400 euro
building license and a lifetime free advice: 500 euro