Wind Tunnel Data Reduction Tool

Getting Started

Click here for more detailed instructions on how to build your Wind Tunnel Model.

You will need to produce 3 total Wind Tunnel models

Basic: No control surface deflections
Pitch Control: Pitch control surfaces deflected 10 degrees Trailing Edge Up (TEU).
Directional Control: Rudder deflected 10 degrees Trailing Edge Left (TEL).

Making the Models

Open your *.ntop model.
Position the controls as necessary.
Export the OML to the CAD folder: ./CAD/FILENAME.implicit
Open MakeWindTunnelModel.ntop (which you can download HERE).
Position the Sting/ForceBalance Center at your desired CG.
Export your model in a format readable by the PRUSA 3D-printing software: ./3D_Printing/FILENAME.stl
Here are some templates for your Prusa printing project. Pick the one that corresponds to the printer you want to use:
Get it on the printer!

NOTE:

Keep the wingspan ≤ 18 inches; bigger is better.
Be sure not to put any supports inside the cavity that receives the sting mount.

Test data

This is your aircraft JSON or JET11 workbook.

Choose your JET11.json or JET11.xlsm

This comes from the Wind Tunnel.

Choose your WindTunnelData.mat

MATLAB v7.3 (HDF5) files are not supported; re-save them as v7 or v6 before loading.

Show JET11 derived predictions

Full-scale geometry

Planform area, S (ft²) Mean chord, MAC (ft) Wing span, b (ft) Static margin— Center of gravity (ft) Neutral point (ft)

Model scale, 1 to : Desired static margin

Scaled model geometry

Planform area, S

Wing span, b

Mean chord, MAC

Center of gravity

Neutral point

Reynolds Number Correction

Correct to this Alt (ft) Correct to this Mach Wind-tunnel Re Corrected Re Reynolds Number correction weight (w)

C_{D 0, corr} = C_{D 0, WT} [1 + w ({(\frac{{Re}_{model}}{{Re}_{Eval}})}^{0.2} - 1)]

Moment Assessment Position:
Relative to Force Balance

X_shift (in)To noseTo tail Y_shift (in) Z_shift (in)

Determine Neutral Point from Data

Wind Tunnel Assessed NP: 21.1 ft

Manual NP (ft from nose)

Slider range: enter the full-scale wingspan. Manual entry overrides the slider and can be outside its range.

Move the Wind Tunnel Assessed NP Slider until the slope of the plot below become zero (flat). That is your Neutral Point according to the WT Data.

C_M vs. Angle of Attack at Trial Neutral Point

Select the MAT-file exported by the wind-tunnel system.

Support/Standoff Correction (optional)

Run the external support or standoff in the tunnel without the aircraft. Load that MAT-file here to subtract its lift, drag, and moments before calculating coefficients.

Drop or choose a support-only .mat file

Use the same MAT format, tunnel conditions, force-balance reference, and angle-of-attack test-point order as the aircraft run. Saved JSON contains the corrected loads.

No support correction applied.

Ready for wind-tunnel data