Incidence gauge

Anyone got one or ever used one? I could do with one but they seem bloody expensive.
Thought about making one???

I presume you mean an Incidence gauge.
What do you want it for? A straight-edge is just as good, and a darn sight cheaper!
Depending on the aircraft's purpose there are two possible options for setting
A) - Aerobatic model - the centreline of the wing, the tailplane, and the thrust-line should all be zero (dead straight!) ((and it's usually a shoulder wing, too, so all the draggy bits are in line.))
Trainer/slow glider/sport model - Leading edge of the wing slightly higher that the (usually flat plate) tail line, and a bit of down thrust. It doesn't matter if the whole wing is higher or lower than the t/p, a simple tape measure from the parallel, at the trailing edge, and leading edge will tell you how it is tilted, if the mk 1 eyeball doesn't.
You often find that the top of the fuselage (occasionally the underside) is parallel to the tailplane zero anyway.
Don't forget - it is not the flat underside of the main wing we are looking at, it is the centreline. If the flat underside of the wing is parallel to the line of the tail, that is probably enough + incidence.
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If you really want to, you can buy a nice expensive gauge, that will be used once, now and then. and even after measuring everything to the n'th degree, the first flight will tell you 'something' needs adjusting!

I have one, and very useful it is but you can do just as well with a cheap laser pointer and a 6" rule. You phone also has an angle measuring system but it's only accurate to 1 degree.

My phone is attached to the wall, Klippy! That makes using it as a measure a bit tricky! [badass]

Paul
I had a Robart incidence gauge many years ago, it was useful.

I dont have one now as I rig all of my aircraft over an engineers surface table, so I measure up from what is effectively a fixed and very flat ground.

You could easily make a really nice incidence gauge using the inclinometer function in a smart phone.
You will do better than the 1 degree resolution that Klippy mentions, they must have some old smartphones out in the jungle.

I have just looked at the robart website and they even do the hardware to go with a smartphone, would be no problem to cobble something up to do this.

B.

robart.com/collections/hobby-tools-meter...tors/products/404-v2
cdn.shopify.com/s/files/1/0339/0713/file...98fca7aa2f9.pdf?3671

Eric wrote: I presume you mean an Incidence gauge.
What do you want it for? A straight-edge is just as good, and a darn sight cheaper!
Depending on the aircraft's purpose there are two possible options for setting
A) - Aerobatic model - the centreline of the wing, the tailplane, and the thrust-line should all be zero (dead straight!) ((and it's usually a shoulder wing, too, so all the draggy bits are in line.))
Trainer/slow glider/sport model - Leading edge of the wing slightly higher that the (usually flat plate) tail line, and a bit of down thrust. It doesn't matter if the whole wing is higher or lower than the t/p, a simple tape measure from the parallel, at the trailing edge, and leading edge will tell you how it is tilted, if the mk 1 eyeball doesn't.
You often find that the top of the fuselage (occasionally the underside) is parallel to the tailplane zero anyway.
Don't forget - it is not the flat underside of the main wing we are looking at, it is the centreline. If the flat underside of the wing is parallel to the line of the tail, that is probably enough + incidence.
-
If you really want to, you can buy a nice expensive gauge, that will be used once, now and then. and even after measuring everything to the n'th degree, the first flight will tell you 'something' needs adjusting!

You forgot C Eric, a high performance pylon model ( my slicker) the plan calls for the wing and tail to be set at specific incidences ( thanks for the spell check) You need to bear in mind this model was at the pinnacle of what was thought possible when it first flew and i plan to use it as designed, short ( 25 second) vertical climb followed by a long glide back down, the radio is only there to keep it in sight. The wing needs to be set at 4 degrees and the lifting tail at 2.5. I have taken extra care in the wing and tail seats as well as trigging out the angles and heights but I'd just like to get it set up correctly rather than resort to jacking bits up later on ( the tail will be fixed rather than banded on) plus I'd be interested to measure a couple of other models just out of interest.
Thanks for thoughts and advice Barrie, the main crutch of the model is at zero degrees so providing I level that I can take the incidences from there. I'll have a look at the smart phone app but I've found the compass app is out compared to my 'real compass, wonder if the incidence app is the same??

paul d wrote: You forgot C Eric, a high performance pylon model ( my slicker) the plan calls for the wing and tail to be set at specific incidences ( thanks for the spell check) You need to bear in mind this model was at the pinnacle of what was thought possible when it first flew and i plan to use it as designed, short ( 25 second) vertical climb followed by a long glide back down, the radio is only there to keep it in sight. The wing needs to be set at 4 degrees and the lifting tail at 2.5. I have taken extra care in the wing and tail seats as well as trigging out the angles and heights but I'd just like to get it set up correctly rather than resort to jacking bits up later on ( the tail will be fixed rather than banded on) plus I'd be interested to measure a couple of other models just out of interest.
Thanks for thoughts and advice Barrie, the main crutch of the model is at zero degrees so providing I level that I can take the incidences from there. I'll have a look at the smart phone app but I've found the compass app is out compared to my 'real compass, wonder if the incidence app is the same??

......and D) Some of us like buying or making tools and get a kick out of using them.

Yep!!!

Point of order!
You don't have to keep repeating the whole post when you reply!
Either copy-paste the relevent bit, or put XX said zzz - - and go on from there!
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So - STF, with the wing at 4' and the tail at 2.5' That's the same as having the tail at zero, and the main wing at 1.5'! The model will be flying so slowly that the drag from the fuselage will be negligible!
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But then - the only time I fly free-flight is when the radio quits after take-off - (almost never happens these days!) - and the resulting passage through the air is usually a downward facing parabola! :pinch: :S

Eric wrote: Point of order!
You don't have to keep repeating the whole post when you reply!
Either copy-paste the relevent bit, or put XX said zzz - - and go on from there!
-
So - STF, with the wing at 4' and the tail at 2.5' That's the same as having the tail at zero, and the main wing at 1.5'! The model will be flying so slowly that the drag from the fuselage will be negligible!
-
But then - the only time I fly free-flight is when the radio quits after take-off - (almost never happens these days!) - and the resulting passage through the air is usually a downward facing parabola! :pinch: :S

Is it a big deal?
Actually I did crop the full quote to just Pauls' reply and what you attribute to me is none of my reply.
I thought I was posting on the Aeromodellers forum not Modelflying........ My mistake.......

No Eric, if the models flying straight and level the incidences ( of the flying surfaces)are still +4 and +2.5 , for the wing to be at zero the nose would be pointing down.
Anyways Im going to have a go at making one, just found my ancient protractor.

paul d wrote: No Eric, if the models flying straight and level the incidences ( of the flying surfaces)are still +4 and +2.5 , for the wing to be at zero the nose would be pointing down.
Anyways Im going to have a go at making one, just found my ancient protractor.

Post what you do on here Paul, I'd be interested it what you come up with.

Actually I got my last post wrong!! the incidences are set from the models datum so it doesn't matter whether the models nose up/ down it doesn't change.

If your wing is at zero aoa, then you have no lift being generated!
If the wing is set to fuselage datum, then the aircraft will be flying with the fuz tail-end dangling - looks untidy, to say the least! :evil:

Paul

At least with using a smartphone as an inclinometer with the appropriate app, you can check accuracy with some simple trig and blocks. Once established then you can just get on using the gauge and smartphone.

My tests have been very positive in this respect.

B.