Good point Terry. I may not use tables anymore - always interpolating the table anyways.You don't really need the tables, just divide the no. of degrees you move the prop by 360 then multiply by the dial reading.
If you think about it a second pitch is how far the prop would advance in one complete revolution. If you just measure part of a rev. you just need to take that into account by dividing by 360.
Good point Terry. I may not use tables anymore - always interpolating the table anyways.You don't really need the tables, just divide the no. of degrees you move the prop by 360 then multiply by the dial reading.
If you think about it a second pitch is how far the prop would advance in one complete revolution. If you just measure part of a rev. you just need to take that into account by dividing by 360.
Time to make a spreadsheet.
Terry they just numbers ,,bend and take degree of the clock ,then record.No need for headcase multiplications ha.
Any kind of racing! Take the first 15* from the LE about 3/4 out from the C/L, multiply by 24 to get "full circle" pitch then use that in the formula to see "potentially" how fast a prop will go.I guess if veiwed from a SAW perspective that's understandable.Cheers
I didn't reply correctly and yes you are right any racing,,I Just don't go into that depth of measure,,but thanks for the formula..Any kind of racing! Take the first 15* from the LE about 3/4 out from the C/L, multiply by 24 to get "full circle" pitch then use that in the formula to see "potentially" how fast a prop will go.I guess if veiwed from a SAW perspective that's understandable.Cheers
For a light, clean running hydro I've found 10% - 15% slip is about right, monos as much as 25%.
Props I'm working with on my 40 hydro have about 4" of LE pitch. So 4 x 24,000 (guesstimate) / 1057 = 90.8 x 0.85 (15% slip) = 77.1 mph
Right in the ballpark!
That gauge is for more than just a overall pitch #.
It dose any thing you want any where on the prop.
Lead in to trailing edge cup.
If you use it right and record your pitch at different points on the prop. You can learn a lot about what dose what as far as pitch is concerned.
Over all pitch average dose not tell the whole store at all.
The first 20deg from the leading edge will tell you how fast the prop can go with no slip % needed in the equation.
Have proved it to my self many times with a eagle tree. Also with the gas guys at the pond with there gun.
Read the 20 deg leading edge at the 70% mark on the prop and then use the equation. pitch x RPM /1057 = MPH always came in at around +/- 2 mph
That gauge is for more than just a overall pitch #.
It dose any thing you want any where on the prop.
Lead in to trailing edge cup.
If you use it right and record your pitch at different points on the prop. You can learn a lot about what dose what as far as pitch is concerned.
Over all pitch average dose not tell the whole store at all.
The first 20deg from the leading edge will tell you how fast the prop can go with no slip % needed in the equation.
Have proved it to my self many times with a eagle tree. Also with the gas guys at the pond with there gun.
Read the 20 deg leading edge at the 70% mark on the prop and then use the equation. pitch x RPM /1057 = MPH always came in at around +/- 2 mph
No slip?
not if you use the first 20 deg from the leading edge as your pitch for calculation.
Check a prop and map it with this gauge. take a reading at every 5 deg mark all the way across the blade at the 70% mark on the blade.
Use any prop you have a good log on the RPM and speed.
Let me know what you see?
No slip?
not if you use the first 20 deg from the leading edge as your pitch for calculation.
Check a prop and map it with this gauge. take a reading at every 5 deg mark all the way across the blade at the 70% mark on the blade.
Use any prop you have a good log on the RPM and speed.
Let me know what you see?
In the 115 mph range, 15% slip...Must be the prop you are using......... 3.8" to 4" is the range I like to stay in.
6" to 7" of lead in is a lot .....
Then again I never tried to set any speed records just heat race.
so how fast dose it go with 6" and 24K? my calculations show 136 with no slip.
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