Re: Prop Efficiency

From: markdrela <drela_at_mit.edu>
Date: Mon, 28 Aug 2006 17:18:39 -0000

--- In Indoor_Construction_at_yahoogroups.com, "John Kagan"
<john_kagan_at_...> wrote:
>
> After playing around a bit, I think I found the (or at least "a")
> problem: there is a small set of airfoils (with a specified Re) to
> choose from. I picked a 6% arc airfoil with a Re of 50,000 - the
> closest thing it had to an indoor airfoil. But I think the
> relatively high Re might be skewing things.

Yeah, that Re is at least 10x too big.

If you give me the prop geometry in the following format,
root to tip, I can easily run it with the appropriate airfoil numbers.
The radial spacing is arbitrary -- you just need enough points to
define the planform and twist adequately. Inches are OK for the units.

# radius chord angle
   0.20000E-01 0.15816E-01 84.9498
   0.40000E-01 0.31006E-01 76.7416
   0.60000E-01 0.44295E-01 69.1633
   0.80000E-01 0.54513E-01 62.3656
   0.10000 0.61066E-01 56.3885
   0.12000 0.63979E-01 51.1954
   0.14000 0.63651E-01 46.7095
   0.16000 0.60566E-01 42.8396
   0.18000 0.55101E-01 39.4964
   0.20000 0.47369E-01 36.5991
   0.22000 0.36939E-01 34.0781
   0.24000 0.21305E-01 31.8749
   0.25000 0.11536E-01 30.8925


It would also be interesting to run the same blade shape with two
different RPMs, corresponding to a VP change.
Received on Mon Aug 28 2006 - 10:19:30 CEST

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