Institute of Aerodynamics und Gas Dynamics

Model construction LWT

including construction guidelines for externals users

Models from our construction workshop

Wind tunnel models of high precision are built in positive and negative methods for our own requirements and measurements for industry partners.

Sample of a semi shell with pressure taps
Sample of a semi shell with pressure taps

Construction guidelines for airfoil models in the Laminar Wind Tunnel

Standard chord length of airfoils: c=0.6m, c=0.8m

Range of Reynolds numbers:

t=0.6m: Re from 0.5*106 to 3*106

t=0.8m: Re from 0.7*106 to 4*106

Airfoil structure:

The models are mounted vertically in the test section with the help of a rod of 30 mm diameter, which passes through the model at the c/4 point. The models are fixed against rotation only at the upper end rib.

An approx. 20 mm thick plywood rib must be implemented in the sides of the airfoil in order to gain enough rigidity for the building-in of the fittings.

The airfoils have to be manufactured very carefully to ensure a high parallelism and rectangularity and must have a  wing span of 730 ± 2 mm.

The airfoil is attached in the wind tunnel with the fittings B1, as well as with a rod of 30 mm diameter, which goes through the fittings of B1 and B2 at c/4. The thread M12 at the fittings of B1 must be extended through the plywood rib.

For flapped airfoils a template of the upper side has to be made to enable the adjustment of the reference angle of the flap.

The gap between the flap and the airfoil has to be as narrow as possible. Friction should be reduced to a minimum when the measurement of the pitching moment of the flap is necessary.

The flap fittings must not stick out of the maximal wing span of 730 mm. The fittings must be produced and attached according to the drawing.

The flap is fixed with the help of the flap fittings K1.

Parts list:

For the flap:

1 flap fitting K1
1 flap fitting K2 
2 flap fittings K3
2 flap fittings K4
8 low-headed screws 4 x 15 DIN97
2 ball-bearings 10 x 3 (SKF 623)

For the airfoil:

1 big fitting B1
1 small fitting B2
8 low-headed screws 4 x 20 DIN97



This picture showsWerner Würz

Werner Würz

Head working group Laminar Wind Tunnel

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