X-Mozilla-Keys:
Paul wrote:
Perry Mick wrote:
Paul wrote:
Perry what takes longer to build a new prop or a new duct?
I am also curious about the latest carbon fiber prop.
What is the tip thickness? Have you tried coating the
inside of the duct with spray foam and letting the
prop machine it to the right size?
It take about the same amount of time, about 2 months,
at my 1 hour/day work rate (the real world gets in the
way).
I had closed up the gap closer with this prop than the
previous, but vibration cause it to open up a little
(tips hitting, grinding off some micro and some of the
prop tips). I think the gap is about 3/32 inch. But now
that the prop is dynamically balanced, I can probably
close up the gap some again. I don't think it could
get much better than 1/16 inch. Also don't think it
would cause a significant change in performance.
Here are some rough numbers on the props:
Prop 2: root blade thickness: 1 inch, tip blade thickness:
0.4 inch, chord: constant 4 inches.
Prop 3: root blade thickness: 0.5 inch, tip blade thick-
ness: 0.2 inch, chord: 4 inches root, linear taper to
2.5 inches at the tip.
The new prop does have light blades!
Any twist in those blades?
Yes:
Blade 90-blade
Radius Cord Thick. Angle Angle
4.0 4.00 0.49 64.00 26.00
4.5 3.95 0.46 60.95 29.05
5.0 3.90 0.43 57.90 32.10
5.5 3.85 0.41 54.85 35.15
6.0 3.80 0.38 51.80 38.20
6.5 3.75 0.36 48.75 41.25
7.0 3.70 0.34 45.70 44.30
7.5 3.65 0.32 43.65 46.35
8.0 3.60 0.30 41.60 48.40
8.5 3.55 0.28 39.55 50.45
9.0 3.50 0.26 37.50 52.50
9.5 3.45 0.25 35.90 54.10
10.0 3.40 0.23 34.30 55.70
10.5 3.35 0.22 32.80 57.20
11.0 3.30 0.21 31.30 58.70
11.5 3.25 0.19 30.10 59.90
12.0 3.20 0.18 28.90 61.10
12.5 3.15 0.17 27.75 62.25
13.0 3.10 0.17 26.60 63.40
13.5 3.05 0.16 25.65 64.35
14.0 3.00 0.15 24.70 65.30
14.5 2.95 0.15 23.80 66.20
15.0 2.90 0.14 22.90 67.10
15.5 2.85 0.14 22.15 67.85
16.0 2.80 0.14 21.40 68.60
16.5 2.75 0.14 20.70 69.30
17.0 2.70 0.14 20.00 70.00
17.5 2.65 0.14 19.35 70.65
18.0 2.60 0.14 18.70 71.30
18.5 2.55 0.15 18.30 71.70
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