Incidence Meter/Gauge Measurement

[Capt Kremen]

My old Robart Incidence Meter/Gauge has given of its best and I am in need of a new Incidence Meter. Reading the reviews it seems the quality of currently available and advertised meters is less than ideal! This includes the Robart, Multiplex and E-Flite devices, all seeming now to suffer from inferior materials, construction and resultant inconsistencies in readings & results.

I have checked the helicopter specialist suppliers, thinking they surely must have accurate meters for setting blade angles, tracking etc. nothing apart from the less than ideal brands already mentioned.

So, any recommendations for a consistent, precision, quality incidence meter?

How many even bother to check and correctly set incidence(s) these days, given the dominance of ARTFs???

[Peter Miller]

I have a Robart incidence meter that I never use. Most of my designs are set up 0-0 and I also use the old Burgess Powerline level.

I am open to offers. PM me.

[Craig Carr]

I’ve been using the QUS smart meter recently and it’s superb

click here and scroll down to model aircraft

it was mentioned in RCME a few year back and it’s proved its weight in gold

The great thing with it is because it links to your smartphone you can take a picture of your set up with the incidences recorded See these examples (I’ve just laid on wing for demo, you need to use the full set up with leading and trailing edge brackets in the final pic for accurate readings)

 

 

 

 

Edited By Craig Carr on 30/08/2019 18:28:29

[Manish Chandrayan]

Why not just use your smartphone with a clinometer app? These are pretty accurate.

[Cuban8]

Dead easy to make your own - plans on the web and an inclinometer from Ebay. Very accurate and not expensive. My Robart is at the back but just too small for the 1/3 scale Turb.

Had this published in the mag a while back.

[Martin McIntosh]

I have an Accupoint laser meter from Great Planes. Fine for incidence but useless for the thrust line due to the weight of the unit. Prior to getting this I made my own using alloy tubes and a simple adjustable laser pen but it was a little on the heavy side which distorted the readings.

[robert chamberlain]

I have always used the old Robart unit with the little needle that swings. I understand there is a new unit with a screen and digital read out,but have never seen one. I have a friend ( odd, is it not) that uses what looks like what Cuban8 has in his picture, and he uses it to set up machines for metal work. I bought a similar unit , which looks like what Cubban8 has in the picture but got it from the model train people. They use it to set up grade incline for their train sets only it reads in percent grade. 45 degree angle is 100 present grade. Just got it.---Bob in KS

[PatMc]

Just curious, what are people checking the incidence angle with respect to & what's the reason(s) for the checks ?

I can see that this meter could be useful to check that wings plugged in to a fuselage are at the same angle but that can easily be checked during &/or after build by other methods. Other than that I'm struggling to think of any justification for this gadget.

[Peter Jenkins]

Hi PatMc

Don't know about others, but I fly F3A aerobatics and it is an essential tool to ensure that you have the motor, wing and tail incidences set to the recommended set up. You do need to set a datum to measure from - often the flat fuselage part the canopy rests on. They do not come pre-set even if they are ARTF. Once you fly then there are probably minor tweaks required e.g. re-setting wing incidence to eliminate any trim you have had to dial in to fly wings level. Also essential when trimming the aircraft to go up vertically and down vertically although in the latter case, a mix with elevator to throttle might be the only solution. Motor thrust line can be a very important figure to ensure that motor goes back in the same position after any maintenance e.g. greasing gearboxes used on in-runners or for contra prop gearboxes.

[SIMON CRAGG]

I have been using the Robart versions for many years. You are right, some of them seem to "stick" others seem free and very accurate. IMHO these are an essential bit of kit to the serious modeller. I check every model prior to the first test flight, and virtually all of them (including foamies) require some adjustment (usually wing twist). A degree or so on a big trainer is not a big deal, but on a 6s powered Hawk, a different story. Also been playing with some phone apps, but even these need checking as can be way out!.

[robert chamberlain]

My daughter says she can get degree measurements using her I-phone.---Bob in KS

[PatMc]

Posted by Peter Jenkins on 01/09/2019 02:23:38:

Hi PatMc

Don't know about others, but I fly F3A aerobatics and it is an essential tool to ensure that you have the motor, wing and tail incidences set to the recommended set up. You do need to set a datum to measure from - often the flat fuselage part the canopy rests on. They do not come pre-set even if they are ARTF. Once you fly then there are probably minor tweaks required e.g. re-setting wing incidence to eliminate any trim you have had to dial in to fly wings level. Also essential when trimming the aircraft to go up vertically and down vertically although in the latter case, a mix with elevator to throttle might be the only solution. Motor thrust line can be a very important figure to ensure that motor goes back in the same position after any maintenance e.g. greasing gearboxes used on in-runners or for contra prop gearboxes.

Peter, thanks for the reply but not sure why it's regarded as an essential tool when you have to reset incidences anyway during the trim process.

Actually I was more interested in how & why the gadget is used for more typical types of sport & scale models.

[Peter Jenkins]

PatMc, you do need an instrument to set up incidences accurately before initial flight. CG position is the starting point for trimming and affects all other adjustments. Moving the CG, generally to minimise or eliminate coupling in knife edge and possibly altering wing incidence to counter pitch up/down in vertical up and/or down lines. The average modeller would be amazed at how much nicer even something like a Wot 4 becomes when it has been properly set up although you don't necessarily need an incident gauge to do that.

[Geoff S]

Posted by PatMc on 31/08/2019 22:19:54:

Just curious, what are people checking the incidence angle with respect to & what's the reason(s) for the checks ?

I can see that this meter could be useful to check that wings plugged in to a fuselage are at the same angle but that can easily be checked during &/or after build by other methods. Other than that I'm struggling to think of any justification for this gadget.

I have a Robart gauge and use it regularly though not frequently. It's particularly useful with biplanes where the top wing incidence isn't fixed by the fuselage (which, in a decent kit, can be set accurately) but by a cabane structure which often has quite a vague position. I just like to be sure the set up is somewhere near what I expect so I have fewer potential problems on the test flight. You can also check that the wing incidences at root and tip are the same - or at least washed out rather than in.

They 're also useful for setting engine/motor side and down-thrust.

I last used the Robart device for checking the wing incidence relative to the tail-plane on the Ryan ST I'm building from the Easy Built kit (which is more like scratch building). I just wanted to be sure things were where they seem reasonable to be - the wing is 1 degree +ve

A lot of my professional life involved measurement so I suppose it's what I'm used to and aeromodelling is something I took up late in life.

Geoff

[PatMc]

Geoff, the incidences of biplane wings & washout did occur to me but I've always managed quite easily with bits of string, a ruler & basic trigonometry, so dismissed them as any reason for the gadget.

Side thrust set using an incidence gadget ? I rarely use any, prefer the full size approach of rudder trim.

Down thrust, I don't believe in the term. I always set the horizontal thrust line relative to the wing incidence at the build stage.

[kenking-King Design]

A Wixey digital angle meter from eBay will set you back around £25, and can be the basis of a home-made incidence meter to your own design. Great little units, and as accurate and repeatable as you are ever likely to need.

I have no connection; I'm just a satisfied user.

[Steve Dunne]

I made this incidence guage some 30+ years ago out of scrap bits, when building a 1/4 scale Fokker DVII. It has been used regularly since then, both by me and by the several friends who borrow it from time to time.
No technology, just a dangling pointer!
The rubber band keeps the system in tension during measurement.
The slots in the top part are to slide over prop shafts to get the down-thrust.
Simples .

Steve.

 

Edited By Steve Dunne on 03/09/2019 15:05:57

[Alan Hilton]

My many years old Robat meter was sticking .I took it apart and found the paper scale had wrinkled causing the problem ,reattached the scale and solved the problem .

Alan

[Peter Jenkins]

Posted by Alan Hilton on 03/09/2019 18:02:20:

My many years old Robat meter was sticking .I took it apart and found the paper scale had wrinkled causing the problem ,reattached the scale and solved the problem .

Alan

Must remember that!

[Erfolg]

I seem to be nearer the Pat mac approach.

I have two +48" spruce spar type sections. On the main wing I attach the spar using elastic bands. I then pack the spar near the LE &Te with bits of balsa, until equi distance to the 0-0 line of the section.

Ithen level the plane.

I then check that the spar is level with a spirit level. On a flat plate tail plane I then just stick my spirit level on it. If a bit fancier I pretty much set up as the wing.

Assuming all is not well, I just use the second spar on the tail plane. After that it is a simple bit of maths (trig) to measure a base line, taking measurements to find the opposite triangle length.

The difference will only be a degree or so, a bit of fettling, will bring both to the 0-0 line.

The down thrust and upthrust issue is about turning moments. Most of modern acrobatic models have pretty much got all the drag inducing components in line along the thrust line. The UC and that tiny wing (canuliser what ever that means?) will change their drag value with speed. As will the section pitching moment with AoA. For the rest of us the thrust line is a compromise, which is at best right at one speed, the rest of the time, it is not perfect, if you get my drift as all the other bits and pieces have changing drag values someway from a moving neutral point (at any moment in time).

Edited By Erfolg on 04/09/2019 15:47:55

[cymaz]

I saw THIS on the Robart page for sale. Nearly bought it until they wanted to charge $40 shipping.

Anyone with a 3D printer could make one up in no time....someone up for it?

[Peter Miller]

FIVE DOLLARS for four replacement rubber bands!!!???

[bert baker]

Yes but they are Smartphone rubber bands

[bert baker]

To some degree if the wings are fitted to a none adjustable wing seat, as long as it’s built reflects the plan then it should fly as the designer had intended,,

I like many others have built loads of planes from plans and kits and never had any incidence meters.

Yes they were available, but there were limited ones available back then

Does look like same thing is true today.

[Rich too]

Posted by bert baker on 06/10/2019 08:42:38:

To some degree if the wings are fitted to a none adjustable wing seat, as long as it’s built reflects the plan then it should fly as the designer had intended,,

I like many others have built loads of planes from plans and kits and never had any incidence meters.

Yes they were available, but there were limited ones available back then

Does look like same thing is true today.

Same here, never used one in forty years and rarely had a poorly flying plane.

I guess if I were into competition flying I might use them.

Edited By Rich too on 06/10/2019 09:36:41