stunthanger.com
General control line discussion => Open Forum => Topic started by: Curare on May 31, 2018, 04:37:13 PM
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Hey all, just wondering if there's a decent source for a pitch guage these days. I think I'd prefer something a bit better engineered than a prather or a Hooptie guage.
So, where to get one?
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This one just appeared in RCG. https://www.rcgroups.com/forums/showthread.php?3084938-Prop-Pitch-Gauge-New
Norm
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This one just appeared in RCG. https://www.rcgroups.com/forums/showthread.php?3084938-Prop-Pitch-Gauge-New
Norm
Nice except for this detail: "Measure from 3" to 9.8 inch"
Unless you are focused on smaller planes, I would think you would want to have something that allows for larger props.
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If that’s 3”-9.8” of pitch ( not diameter) that’s a pretty good range.
Dave
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According to the scale reading on this instrument the maximum radius measured is 90 mm = 3.54 inches, not enough for our needs for Stunt. For Stunt you need something that will measure to a radius of at least 6 inches and even then you're a bit short on 13 inch props!
Nice looking unit but it's designed for FAI Speed props!
Randy Cuberly
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Bob McDonnald made these a few years back. I don't know if he still has any. It works for both tractor and pusher props up to 13 inch diameter. Its a double sided placard that is reversible. Works pretty well.
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Bob McDonnald made these a few years back. I don't know if he still has any. It works for both tractor and pusher props up to 13 inch diameter. Its a double sided placard that is reversible. Works pretty well.
I have one of these as well, nice unit.
James
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Don't know what's wrong with the Prather gauge, been using one for 30 years so I guess I'm use to it.
Not a thing wrong with the Prather... other than they are out of production and I haven't been able to find stock in years... love mine, except the holder rocks in the slot, so I got an aftermarket holder (I think Jim Lee still makes holders for them). Brad Walker shared plans for a stellar pitch gage here a few years ago that could hold our size props and even larger, was even better engineered than the Prather, and I was shocked no one decided to have a batch cnc made, because that kind of item could sell cross platform to CL and RC.
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My holder doesn't rock because I hold the whole thing in my left hand so it's clamped down but I can still slide it with my fingers.
I actually like my Prather gage since I got one of the sliders that actually fits from Jim Lee. I also do the hold the whole thing in one hand and manipulate with the fingers so the fight hand can keep the indicator in place and firmly against the prop. I use it a lot.
I'm not sure how accurate they are in terms of absolute value but it really doesn't matter as long as it's consistent and repeatable. They really should be used just as a reference for modifying a prop for more or less pitch at various stations. This whole thing is trial and error. While it's true that having a starting point is handy in getting things to work there are too many variables to really expect find a solution to all the problems associated with the airplane, engine (or motor), and prop in one setup. It's definitely what is referred to as a "Many Body Problem".
I'm not sure anyone knows what the real value in terms of pitch is with an under cambered prop, for instance, is anyway, and a lot of the props I find I'm using these days are just that!
Anyway I think the Prather works well enough for our general purposes of comparison! n~ n~
Randy Cuberly
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Don Ogren made one....I'm not sure that he still does.
I found that mine closely mirrored the Prather.....
And it was/is vewry affordable.
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Have you ever tried to use your phone to meassure the pitch???
It is rather simple.
- Mark the diameters at which you want to meassure the pitch on the underside of the prop
- Place the prop upside down on a table
- Download an App for your phone to meassure inclination (Protractor App)
- Place the phone on the back of the hub and push "Tare" or "0". the back of the hub will now be the datum of the meassurements. Therefore it doesn't matter if your table is level.
- Place the phone on the mark on the back of the blade and read the relative angle between this station of the blade and the hub on your phone
- Now all you have to do is some math.... you could make a small excel spreadsheet that runs on the phone as well to assist with this task.
And PRESTO!!! You have your pitch!
Regards
Frank Wadle
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I think this is still available.
Aki
http://www.pylon-line.co.uk/pylon%20line%20accesories.html
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Have you ever tried to use your phone to meassure the pitch???
It is rather simple.
- Mark the diameters at which you want to meassure the pitch on the underside of the prop
- Place the prop upside down on a table
- Download an App for your phone to meassure inclination (Protractor App)
- Place the phone on the back of the hub and push "Tare" or "0". the back of the hub will now be the datum of the meassurements. Therefore it doesn't matter if your table is level.
- Place the phone on the mark on the back of the blade and read the relative angle between this station of the blade and the hub on your phone
- Now all you have to do is some math.... you could make a small excel spreadsheet that runs on the phone as well to assist with this task.
And PRESTO!!! You have your pitch!
Regards
Frank Wadle
I do what Frank does, but with a digital angle gauge: https://www.amazon.com/Wixey-WR300-Type-Digital-Backlight/dp/B00T6YZ0K6/ref=sr_1_3?ie=UTF8&qid=1528416564&sr=8-3&keywords=angle+gauge . I attach it using its magnets to a light steel angle (an Incra bent-edge rule) and hold the rule against a slab of wood perpendicular to the prop while reading the angle. Works a treat. Even slicker is Igor's device that has an accelerometer you hold against the prop and read pitch on a Jeti box. The Jeti box is Igor's universal interface with the world.
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I'd been doing something similar with a protractor and excel, but the whole process felt kinda chintzy... But using the phone is an idea. Wouldn't be that hard to create an app to do this, surely!
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I experimented some with a small laser pointer positioned at stations along the blade. The prop was bolted firm to the counter top and the laser pointer was laid on the flat side of the blade. The red dot was projected 5-6 ft away onto a calibrated scale drawn on a large sheet of paper that I tacked to the wall. Just a thought. Getting the pointer normal to the blade was critical.
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I just read this post and remembered seeing the attached helicopter pitch gauge. At the time I thought about using it just this very purpose:
https://www.aliexpress.com/item/1pcs-RC-Helicopter-Digital-Pitch-Gauge-LCD-Display-Blades-Degree-Angle-for-ALIGN-AP800-TREX-450/32817989916.html
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Hey all, just wondering if there's a decent source for a pitch guage these days. I think I'd prefer something a bit better engineered than a prather or a Hooptie guage.
So, where to get one?
What did you decide to get?
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Could this be made to work? Digital T-bevel.
https://www.amazon.com/General-Tools-828-Digital-Protractor/dp/B00563TLSI/ref=sr_1_1_sspa?s=hi&ie=UTF8&qid=1528761509&sr=1-1-spons&keywords=digital+t+bevel&psc=1
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What did you decide to get?
So far - nothing.