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yankee-flyer

Well Known Member
Let me display my ignorance. I haven't gotten to this point yet but why is the two-piece fixture needed? It appears to just hold the level some distance from the back of the prop (3/4"? 1"??). Why can't the level simply be placed against the back of the blade, contacting the blade at two points instead of the three points as the fixture does. It's not going to be "square" at any point.

THANKS

Wayne 120241
 
yankee-flyer said:
Let me display my ignorance. I haven't gotten to this point yet but why is the two-piece fixture needed? It appears to just hold the level some distance from the back of the prop (3/4"? 1"??). Why can't the level simply be placed against the back of the blade, contacting the blade at two points instead of the three points as the fixture does. It's not going to be "square" at any point.

THANKS

Wayne 120241
Click to expand...

The back of the blade is not flat so the only way to get repeatability is to have the fixture contact the curved surface at 3 places or to make the fixture with the same shape as the blade which is harder to do. It doesn't need to be "square", just repeatable.

Tony
 
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Has anyone checked the blades from side to side using this fixture?

I'm curious as to how close the two blades are using the self adjusting hub. I've tried to use my Warp Drive protractor, but like Tony pointed out the back of the blade is not flat.
 
Difference Between the two blades

Mine was off .8 degrees checked one blade against the other using the digital level method.

John
RV12 N1212K
 
iPhone App as level

Peterk said:
Ditto here. I use the smart level ap on the Iphone.
Click to expand...

Peter, how do you manage to make the iPhone work? Do you measure distance from prop hub center and then somehow hang the phone? Slane
 
Slane said:
Peter, how do you manage to make the iPhone work? Do you measure distance from prop hub center and then somehow hang the phone? Slane
Click to expand...

There's a free ap you can download. You just calibrate it then lay the edge on the hanging fixture you've made for the blade (ala Tony and Scott) and it gives you the angle in hundreths. As everyone has said, you're not looking for a particular angle...just that both blades are the same. Have you read Scott's piece in the latest RVAviator?
 
Peterk said:
There's a free ap you can download. You just calibrate it then lay the edge on the hanging fixture you've made for the blade (ala Tony and Scott) and it gives you the angle in hundreths. As everyone has said, you're not looking for a particular angle...just that both blades are the same. Have you read Scott's piece in the latest RVAviator?
Click to expand...

That makes sense! I have not read Scott's article but will. Thanks and I'll get the app. Slane
 
Scott's article

I purchased the warp drive protractor but as several have pointed out, any device is very difficult to use due to the prop not being flat on the back. So, I too built the 3 point "McDaniels" device that Tony T. so nicely describes in a prior thread. The most challenging aspect of building the device is cutting one the one aluminum angle so that it matches the contour of the back of the propeller blade. I ended up using a contour gauge to do this and it worked perfectly. For those who don't know that a contour gauge looks like- here is a link to one:

http://www.homedepot.com/webapp/wcs...25X-_-100353830&locStoreNum=1950&marketID=234

It will make the measurements very easy and reproducible. I also just read Scott's article- very nicely written and he too describes the device he fabricated.

Jeff
 
Fixture alignment...

Actually, if you make the fixture so that is touches the back of the blade in 3 places as shown here, then there is no need to try to cut the alum angle to match the curve of the blade:
[url=http://tonytessitore.smugmug.com/RV-12-Project-N577RV/RV-12-Tools-Work-Fixtures/7992519_GYr3k#932235457_yDgay-A-LB][/URL]

Here is what it looks like from the front with the top angle lying on the trailing edge of the blade and the sighting notch lined up with the paint stripe:
[url=http://tonytessitore.smugmug.com/RV-12-Project-N577RV/RV-12-Tools-Work-Fixtures/7992519_GYr3k#913401716_x8tB5-A-LB][/URL]

Tony
 
More pics...

MartySantic said:
Can you fellows post a picture or two of the fixture you have fabricated??
Click to expand...

I used some left-over 3/4 X 3/4 alum angle that was included in one of the kits as a packaging stiffener for some hinges (I think).

Initial fabrication:
932579399_oY6C6-S.jpg

I initially cut the alum angle so that it only touches the back of the blade at the two arrows. It was not stable in all directions.

Then added this tab at the end to make the fixture touch the back of the blade at 3 places to make it stable:
932579319_MEFnR-S.jpg


Tony
 
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Thanks Tony. I would venture to guess with your fixture, there should be no need to match the curvature of the back of the blade. Makes fabrication, a bit easier.
 
Iphone App

can U tell me the name or version of the Iphone App you guys used for the prop measurements please?
 
Iphone used for setting pitch angle

I made up a bracket so I can use my Iphone to check both blades of my prop are the same pitch. It works well and is easy to use.

IMG_5459.JPG

IMG_5462.JPG


I am also working on using the Iphone for dynamic prop balancing using the built in motion sensors with an application called Viabration, could save using expensive equipment.

Tony
 
Good job Tony

Do you have to slide the bracket on from the end of the propeller? It would be great if that bracket were made of plastic so that it would not scratch and if it were available for purchase. It would not necessarily have to be made for the iPhone. Two parallel places to rest a digital level would work.
Joe
 
Viabration sensor

Tony is the name pf that Iphone application just Viabration? as I cannot seen to find it ...Thnx Mate.

Platyius said:
I made up a bracket so I can use my Iphone to check both blades of my prop are the same pitch. It works well and is easy to use.

IMG_5459.JPG

IMG_5462.JPG


I am also working on using the Iphone for dynamic prop balancing using the built in motion sensors with an application called Viabration, could save using expensive equipment.

Tony
Click to expand...
 
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