No, simply multiplying the wind tunnel speed by the scale ratio will not give you the model plane's real-life speed. When dealing with models and scale ratios, it's important to consider that the relationship between various quantities is not always linear.
To scale the wind tunnel speed to the model plane's real-life speed, you need to take into account the scale ratio, as well as other factors such as Reynolds number scaling.
The Reynolds number is a dimensionless quantity used in fluid dynamics to characterize the flow of a fluid around an object. It is calculated using variables like velocity, length, and viscosity of the fluid.
When scaling a model, including a model plane, the Reynolds number must be preserved for the flow around the model to be similar to the flow around the full-scale object. This means that the velocity of the fluid in the wind tunnel needs to be adjusted to maintain the same Reynolds number.
The scaling of the wind tunnel speed to the real-life speed involves a combination of factors, including the scale ratio, the Reynolds number scaling, and possibly other aerodynamic considerations specific to the model and its intended purpose.
It is best to consult with experts in the field of aerodynamics or wind tunnel testing to accurately determine the appropriate scaling factors for your specific model and desired outcome.