Great Planes AccuPoint Laser Incidence Meter ?

I'm having a problem getting repeatable results with my Great Planes AccuPoint Laser Incidence Meter . There is a small adjustable weight on the laser pointer that allows you to set the level reading. When I initialize this to a "zero" setting then move the fixture to the wing the setting has changed, or moved, or something. Even when I'm VERY careful not to disturbe the laser or balance weight. For example: I put the fixture on the engine prop shaft with the engine mounted on the fuselage and set the pointer to "zero", then move the fixture to the wing, set the wing incidence then move the fixture back to the engine to check the original setting. The pointer "zero" has changed. Have any of you had this problem? and how did you fix it?

You might do a search on RCU, I seem to recall some talk of the bearings having too much friction and maybe needing some lubrication. I haven't used one personally, was thinking about buying one at one time and did some searches. I think RCU is where I read this.

Hi Ron,
We have been using one of these. Ours has a problem in that the plastic bracket used to mount the system to the engine isn't strong enough to hold the bar consistently. When we just use it on the wing and stab, it has worked fine. Our problems have been trying to use it on the engine.
Bill <><

When I got back into the hobby I first bought a laser incidence meter and ran into the same problem you are having. My solution was to purchase a second incidence meter but this time I bought the one with a real meter.

I have my building bench set up so it is completely level (within the thickness of a time card) in all directions. I use the Laser on the wing to be sure it stays put and the analog on the stab. For the engine I have a small pocket level I purchased at Sears that has a V grove in one side. I rubber band the level to the threaded part of the engine shaft. With this set up I can check/adjust all 3 at the same time.

I just used mine this morning, and rereading the instructions, it said that you must support the end of the device when checking the engine incidence. I personally think it is totally useless for this function. It does work well for checking the wing and stab. angles. I set my airplanes up on sandbags, and use a small level on the fuselage, and by giving the meter a little tap, it is fairly repeatable.

In my review for SN, I noted that the engine shaft function was a little flaky because of the compliance in the plastic mount--after a couple of trials, some degree of support of the bar can help but repeatability of this measurement is still less than totally acceptable.

Otherwise, the slight tapping on the bar to settle the pendulum into a repeatable angle and overcoming the stiction inherant in the design will result in excellent measurements.

>When I got back into the hobby I first bought a laser
>incidence meter and ran into the same problem you are
>having. My solution was to purchase a second incidence meter
>but this time I bought the one with a real meter.
>
>I have my building bench set up so it is completely level
>(within the thickness of a time card) in all directions. I
>use the Laser on the wing to be sure it stays put and the
>analog on the stab. For the engine I have a small pocket
>level I purchased at Sears that has a V grove in one side. I
>rubber band the level to the threaded part of the engine
>shaft. With this set up I can check/adjust all 3 at the same
>time.

What device did you use to level your bench that gave you such precision? I need to do it to mine.

>What device did you use to level your bench that gave you
>such precision? I need to do it to mine.

Used 3 different levels to check and double check each other.

1. 6 foot carpenters level
2. Sears Laser Trac laser level
3. carpenters angle indicator I picked up at Lowes.

My bench is an old heavy office desk with a 4'x 6' piece of 3/4 MDF on top. First I made sure it was flat front to back, side to side and corner to corner by shimming between the desk top and the MDF with old time card stock then I adjusted the feet on the desk so it was level in all directions. This desk has adjustable feet so leveling it was a piece of cake.

Thanks

I had the same problem you are talking about so made legs that hold the adjustment wheel longer and now it works fine, for the engine I am going to make an aluminum part that will clamp to the bar in the middle. Here are some photos of my mod.

My recollection is that the GP Laser meter specs claim half the accuracy of that claimed by the Robart Incidence Meter spec sheet, which has no laser. Two (2) is the number you need. Steve

The laser inherently adds nothing to the accuracy. Both of these units utilize the weighted pendulum. The only real difference is the laser unit has a "virtual" meter needle length of 10" so the scale is much easier to read.

FYI