Re: I have the taste of Metal in my mouth!!!
IMHO, not much.
Twist and length are everything, and those are allowed mods in T-6. Blade profiling doesn't really buy you much since the blade profiles used by the teams are experimentally derived supercritical sections from top industry engineers. I haven't heard of any other supercritical design engineers doing work on this problem for air racers.
The biggest reason that twist rules is that most aircraft have terrible aerodynamic issues in the area of the prop that cause the prop to not only fly in "bent" airflow, the airflow is also not consistent around the disc. So the alpha (local twist) that works at one clock position of the arc may be stalled or even negative at another!
T-6's have no significant spinner, a wing mounted well below prop centerline, tons of interference drag disrupting the prop disc, and really obnoxious cooling outlets and exhausts creating radial discontiuities. Forget about trying to do CFD on the flow field; it's just too complex. The fact that they can twist a prop to work in this environment at all is amazing.
Originally posted by Leo
Twist and length are everything, and those are allowed mods in T-6. Blade profiling doesn't really buy you much since the blade profiles used by the teams are experimentally derived supercritical sections from top industry engineers. I haven't heard of any other supercritical design engineers doing work on this problem for air racers.
The biggest reason that twist rules is that most aircraft have terrible aerodynamic issues in the area of the prop that cause the prop to not only fly in "bent" airflow, the airflow is also not consistent around the disc. So the alpha (local twist) that works at one clock position of the arc may be stalled or even negative at another!
T-6's have no significant spinner, a wing mounted well below prop centerline, tons of interference drag disrupting the prop disc, and really obnoxious cooling outlets and exhausts creating radial discontiuities. Forget about trying to do CFD on the flow field; it's just too complex. The fact that they can twist a prop to work in this environment at all is amazing.
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