Sunday, 12 March 2017

Pictures of a model Pou du Ciel / Flying Flea / Himmelslaus

In the open West-Frisian countryside
In the garden
Left side...
... and right side
Engine running

Building this model is not as straight-forward as one would like.
In the first place, there exist no exact drawings of the full-scale aircraft.
The Pou-du-Ciel design was intended for inexperienced home-builders. Building was described by mr. Mignet in a step-by-step, bottom-up fashion, in a book of which the 6th edition (1994) is depicted here. The book contains hundreds of sketches and photographs, but no to-scale drawings. To complicate things further, the original version, which flew well with small engines, rated at about 20 H.P., turned into a killing machine when over-powered, as a result of insufficient pitch control.
It was banned therefore, as a result of which many aircraft of this version survived time and can be seen in museums.
Mignet, however, didn't accept his defeat and came with a second version in 1936, with a controllable rear wing, inversely coupled to the front wing control. This version has the main focus in the later editions of his book, like this 6th, although the first version has been included for the sake of completeness.

There exist some sets of drawings of model Pous, e.g. from Nexus Plans Service (Aeromodeller) and from RCMagazine, but these refer to the first version. Moreover, their construction is quite different from the original construction, on one hand because they refer to English interpretations of the original Pou, and on the other hand because they are intended to fly, understandably.
So it was decided to draw own plans, of the 1936 version, applying the original construction as much as possible. This required a translation of building guidelines to exact dimensions. E.g., building the wing spars required bending the girders under a few bounding conditions. The effect of bending under these conditions was calculated using elasticity theory, resulting in the exact shape.

Wednesday, 8 February 2017

Model details

A closer look
Pilot seat, wind screen, engine and airspeed indicator

Instruments and controls

Airspeed indicator, model Etévé, from WW I
Instrument panel
Instruments from left: rate of climb indicator, altimeter, tachometer, compass, pocket watch
Engine controls: power and mixture levers, near the engine the decompression lever

Control system

Front and rear wing linked together.
Wing actuation levers oriented conversely
Front wing control: stick pushed, trailing edge up
Front wing control, right
Rear wing control: stick pushed, trailing edge down
Rear wing control, right.
Rear wing control, left. Rudder control and rear landing gear
Front wing control, left

Landing gear

Pressed rim wheel, slide bearing
Axle suspension
Sprung rear support


Registration (format abandoned 1929 ;-): H(olland) - P(ou) D(u) C(iel) C(ontrollable)
West-Frisian flag, H(enry) M(ignet) - (model) 14 (version) 2 (1936)

Tuesday, 7 February 2017


Aubier et Dunne, 2-cylinder, 2-stroke, 17 h.p. engine
Carburettor and fuel filter
Fuel and oil supply, fuel gauges and oil flow indicator
Engine with tachometer cable, cylinder lubrication, exhaust tubing, decompression valves and ignition
Exhaust tubing
Cylinder lubrication
Cylinder heads with spark plugs and decompression valves
Engine mounting

Running engine

Not running
Fast running

Monday, 6 February 2017

Building phase


Fuselage sides
Undercarriage and control cut-outs
Fuselage under construction
Fuselage top view
Bottom view
Front bottom view
Fuselage nose
Control stick


Just before covering

 Rear wing

Wing during construction
Top close-up

Front wing

Wing awaiting balsa covering rib fronts 
Wing centre with fuel tank bays and oil can mounting bracket
Before final covering
Wing tip
Fuel tanks and oil tank installed
Brass fuel tanks and oil tank made from oil can


3-D printed engine parts
Just foundry work ...
... after a metallic spray coating
3-D printed small parts: exhaust manifolds, decompression valves and  levers, various oil nipples, carburettor pieces, spark plugs, ignition cable exit box, tachometer pick-off
Engine dummy with built-in electric motor