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Using a Smart phone as an incidence meter

Use your smart phone as an incidence meter

For many years I used the Robart Model Incidence Meter to measure the incidence of my airplanes. To make the process of taking measurements slightly easier, I eventually bought a second Robart so I could use the two in conjunction with one another.

Those meters served me well however I always thought accuracy was sacrificed since the pendulums in both meters had developed a habit of sticking. Plus the so called “precision pointer” wasn’t the easiest thing to read even with good eyes. 

When Hangar 9 released their incidence meter, called the Angle Pro, I saw that as a massive improvement over the mechanical meters. The Angle Pro uses an electronic inclinometer, provides a digital read out and measures in increments of tenths of a degree. A few years ago I purchased the Angle Pro and have not even looked at my old Robart meters since. 

Hangar 9 Angle Pro incidence meter

Hangar 9 Angle Pro

I’m a fairly recent smart phone convert and use all the little goodies far more than I ever imagined. One of those goodies is an inclinometer app. Using this app I simply rest my phone on whatever, and it gives the angle in degrees that it’s sitting at. Kind of like a fancy level.

Using this app at work one day the proverbial light bulb went on and I thought why couldn’t this app be used as an incidence meter? It functions just like the brain of the Angle Pro?

Couldn’t wait to get home and put my brilliant idea to the test. Before any testing could be done I needed to figure out how to make it work so the phone would be a reliable fit on a wing, stabilizer or whatever in order to take measurements. The plan I came up with was to use the optional belt clip that came with my phone cover and simply clip the phone onto the bar of one of my incidence meters.

Smart phone belt clip

With the how figured out, it was to the shop to see if it really worked as slick as I thought it would. I put one of my planes in a stand and set up the trusty Angle Pro on the wing. With that in place, I clipped my phone to the bar so it was sitting right next to the Angle Pro’s brain. Raising the nose of the airplane a few degrees I compared measurements.  The Angle Pro said 3.2° while the app read 3°. Note: The app I used only provides whole degrees.

Using an smart phone with inclinometer app as an incidence meter compared to the Angle Pro

Testing the accuracy of the inclinometer app against the trusty Angle Pro.

The inclinometer app passes with flying colors but the first test of this whole smart phone/incidence meter idea revealed some issues. First one is that the phone is bigger and heavier than the brain unit of the Angle Pro. This may pose a problem on smaller planes or when the end of the incidence meter needs to rest on a control surface. The second issue is that the belt clip is a loose fit on the bar and moves easily. Although I believe this can be easy remedied with some ingenuity.

I came up with another idea for taking measurements that completely voids those first two issues. That is simply resting the edge of phone along the top of the incidence meter bar, as depicted in the picture below to take a reading.

Smart phone being used as an incidence meter

Resting the phone on top of the incidence meter bar to take a measurement

Knowing the phone can be just as accurate as a dedicated meter, there was still one more detail to address… The feature that made the Angle Pro a gift from the R/C gods, which is the ability to zero at any angle. What zeroing does is converts the angle in which the meter is sitting into a new zero point, there by removing the prerequisite leveling of the plane to take comparative measurements.

I’ve been spoiled with Angle Pro’s zeroing function and would not want to do with out it in my smart phone incidence meter. Non-zeroing requires the plane to be leveled first or use of math. I’m all about easy and reliable and prefer the keep the math brain cells out of the process. Before the start of this I searched for an inclinometer app that has the zeroing function. Now I’m an iPhone user and the Apple app I ended up using for this experiment is called U-Clinometer. This is a free app by the way.

For you Android users out there I’m afraid you are on your own finding an inclinometer app with the zeroing feature. I could not find one with a Google search. If you do find one please leave a link in the comments below.

The one draw back with the U-Clinometer app is that only reads in whole degrees, but I guess it depends on how precise you like to be if that’s an issue or not. A free app I do like that does give readings in tenths of a degree, but lacks the zeroing feature,  is called Clinometer HD. Like many free apps there is pay version and it zeroing MAY be part of the upgrade. I did not see it listed in the description and I’m too cheap to test first hand.

The final decision: If I were in the market today for an incidence meter upgrade I would absolutely use the smart phone/inclinometer app along with the frame from an older incidence meter. That arrangement provides any smart phone user a digital incidence meter that measures up to the $60 Angle Pro.

Do you think this set up will work for you? Did you find an app that works better than the ones I listed. Add your comments below let me know what you think.

Iphone using an inclinometer app to measure the control surface movement on a radio controlled airplane

Smart phone can also be use as a deflection gauge


* Reader Curt Sidles has been kind enough to share pictures of how he uses a smart phone and app as an incidence meter. You can read in the comments section some of the details. Thanks Curt!

incidence 1

incidence 4

incidence 3

incidence 2


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  1. Curt Sidles says:

    I use an app. called CARPENTER for the iPhone and iPod Touch.
    It measures to 1/10 degree, includes the zero-reset feature, and is available for free (or if you pay a buck or two you also get a few other features).
    Also, I am using a Harbor Freight 12-inch clamp I bought for $4 with the clamp pads modified to the sideways “V” shape like those on your cannabilized incidence meters.
    Works great to compare incidence angles and measure control throws! 😉
    Happy Landings!

    • Curt, thanks for the heads up on the app, will certainly check it out.

      I’m curious about your Harbor Freight clamp with modified pads. If you could send me a pic of your set-up I would love to see it.


      Edit: Curts pictures have been added to the article

  2. Curt Sidles says:

    Requested snapshots were sent to your email address.
    I used epoxy to attach a Velcro-backed platform to the moving handle on the clamp and I cut V-shaped openings in the bottoms of two small plastic bins. The lids for the bins are attached to the clamp’s pads with 2-sided tape.
    If any unusual shape is needed I can cut the new shape into spare plastic bins, then unplug the old bins from the lids and plug the new ones into the lids.
    Please send me an email if any questions remain or arise.
    Best regards,

  3. Bill Wagstaff says:

    Thanks for an interesting article. Another iPhone app that I am familiar with is MultiLevel, which is free, indicates in tenths of a degree, and has a zero capability.

  4. Glenn Read says:

    What a fantastic site and helpful info.
    Thank you all.

    • Thank you Glenn. Hopefully some new content will be flowing again very soon as one chapter in my life comes to a close and another begins.


  5. Thanks a lot for this great idea!

    On Android I am testing two apps, Clinometer and Toating sphere. First one looks quite precise and stable, while second has zeroing feature…

  6. The Hanger9 Angle Pro Incidence meter device is too heavy to use on foam RC planes.
    The meter bends/deforms an elevator or aileron surface.
    What is needed is a lightweight inclinometer that has Bluetooth transmission and uses the flat lightweight 2016 or 2017 Lithium batteries. Such as device would be light weight and would transmit the incidence measurement to a Bluetooth receiver. The wireless Bluetooth data transmission would eliminate any wire connections to the incidence measuring device. This would work for foam RC planes.

    • Edward, I would welcome that technology to use on any plane. Especially if it had the capability to use several meters together. How nice would it be to have attach a meter to the wing, one to the horizontal stab and one to the firewall, to instantly see how they all relate to one another.

  7. Useful information in this
    article and very creative and
    nice article and this points this a very
    innovative .
    Thank you.

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