Model
RC-model. Built by a friend to investigate possible trouble areas. Flew straight off the drawing board. Performed aerobatics. No tendency to tumble or spin, flown inverted the only problem area it showed was a tendency to Dutch roll with full up elevator at low speed with a period of 2 secs. Normally DR happens with large dihedral and insufficient fin area. The Plank has no dihedral, my theory was the tip rudders above the wing were having a dihedral effect. The fins were modified by adding area below the wing also area increased at the rear. This cured the problem and was incorporated into the design. The full-sized aircraft has no tendency to Dutch roll. See Youtube vids MW10 second flight.
Model photo 2 shows a nose wheel fitted to se if it caused directional problems.
Wing
Wing assembled in my garage. Ribs have a 3mm thick Gaboon ply shear web and a 10x10mm Douglas fir slotted cap strip glued on. Spar tube is 100mm diax1.5 thick 6082-T6. Diagonal brace to support the ribs on two points and chopped strand Fiberglas spar to rib joints.
Wing fuselage assembly
Fuselage
Wing root assembly. Note wing spar slides into the front fuselage tube into a central FG bush and is secured with a pin through the outer lugs. Rear spar slots into the aft tube secured with a pin. The bolted elevon torque drive connection is seen between the spar tubes. The main UC leg is 28mm solid pultruded FG rod.
Cockpit view showing stick and fuel tank. Additional tanks are fitted in the wing roots and gravity feed into the fuselage tank. The fuselage is reinforced with Kevlar and carbon fibre.
This shows the fin and drag rudder assembly. The rudder is made from a piece of Nomex FG sheet. Many aircraft builders’ flyers are also interested in motorcycles. The one behind the fin is a 1936 250cc Rudge racer running on methanol. My other interest is restoring and racing vintage motorcycles.
I like to confirm my stress calculations by structural tests, especially fiberglass which can have quite a large failure scatter. The pic shows the fuselage and seat being loaded with readily available weights. The fuselage is supported at the wing attachment with a prop at the rear to add the engine weight. This puts the fuselage in bending as would occur in flight.
The assembled fuselage structure.
Konig engine installation.
Complete Plank structure prior to covering.
Load testing the rib wing spar about 1980. Torque 8800 Lb in no sign of failure.
Drawing shows typical rib spar FG joint construction. Note the Plank spar is reinforced half way along with another 100mm dia tube split and riveted inside the main spar.
Structure of the MW7 aerobatic ultralight.
views of the completed fuselage
load and balance check.
Aircraft at Headon for initial hop tests.
Headon with crew. L – R Son in laws Roland Altenburg, Andy Cooper, MW, Mike Wood.
Headon. The konig was 1000 RPM down on power, not enough to take off.
New engine fitted. Ciscomotor Bull Max. 33 BHP. 330 cc. Flight achieved. If the borrowed Konig had been satisfactory. The project cost would have been approximately £1000, However with the Bull Max costing £2500 this makes the expenditure about £3500. Still not bad.
LAA rally Sywell 2018, much interest.
After first flight at Shotteswell airfield. Pilot Eddie Clapham. L-R MW, Andy Cooper, George Haffey. Eddie has test flown most of my designs.
Plank road transport. Enstone SSDR rally 1919.