sillyness

My Feedback: (25)

All I can find are offerings from Robart and Great Planes. I saw a guy saying he was using a digital, but he didn't what it was.

Any ideas?

Diablo-RCU

My Feedback: (1)

You want the best? Here it is. Get the Robart V-clamps and a length of aluminum bar from the hardware store. Set this tool on top of the aluminum bar and read the incidence to within 0.1 degree.

http://www.precisionmeasure.com/tool1.htm

sillyness

My Feedback: (25)

OK... so maybe second best.

the-plumber

The Robart unit works well, and [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXPW71&P=ML]this [/link] is 'better', but only because you can use the laser for other tasks.

I found it to be a waste of time to insist on drop-dead incidence accuracy, because while you might get that particular structure (wing, stab, whatever) 'dialed in', the collection of bits we call a model aircraft is a flexible, shrinking-and-swelling-with-every-change-in-temperature-and-humidity beastie. I've found that the Robart meter, and now the laser unit, are more than sufficiently accurate for setting and checking incidence, and that sweating 1/10 of a degree incidence simply wasn't worth the expense in time and aggravation.

I get the thing within a half or quarter of a degree, and the rest is taken care of by trimming the model.

Diablo-RCU

My Feedback: (1)

IMHO it doesn't take me any longer to set the wing donuts with a meter that tells me it's within .1 degree. Less than an hour including the glue and drinking coffee while admiring the job... I know some "builders" who don't even use an incidence meter. Just stand about 10 feet back and say "that looks about right".

MikeEast

My Feedback: (3)

Diablo is right that is THE way to set incidence.. Ours is zip tied on top of the great planes incidence rig. You can dial in to within 1/10th degree and you better believe it matters. If you want any level of precision in your flight this is the way to go. And if you want PERFECTION in your setup here is a free pictoral set of plans a buddy made up of his alignment table. It will allow you to align everything PERFECTLY using 2 craftsman laser levels. If you are a serious builder you NEED these plans this is an awesome tool. Go to www.midcountyrc.com for a free download of the plans in the "how to " section. Look for Buddys laser jig.

the-plumber

While the laser jig is a really neat thing, and thanks for the link I nabbed a copy, it would likely be wasted on my kind of serious building, that is, giant _scale_ models. I often think the term giant scale is misused, and that the normal use these days really refers to giant _sized_ models rather than scale models of large size.

It's one thing to have an airframe which can be aligned to a fare-thee-well, it's quite another to have an airframe which cannot, or more importantly, which will not exhibit any detectable response to airframe misalignments up to and including a quarter or half degree.

The sort of models I'm talking about are for example, a 33% L-4, or Piper Cub with too many windows and funny looking paint. The airframe is so flexible, even after covering, that bolting the wings on at the field can change the incidence one way or t'other - a change which would no doubt be detected immediately in a pattern ship, but which is essentially undetectable in the L-4.

My 33% L-4 has a wing span of 140". Any way you slice it, that's a serious model.

sillyness

My Feedback: (25)

My airframe, quite to the contrary, is very stiff and rigid. Small incidence imperfections would affect it.

I've never check incidence before... just to confirm, I would want to do it BEFORE hinging, correct? I would think I would want to check the flying surface incidence, not the control surface.

Panzlflyer

My Feedback: (15)

Funny how the ones Ive flown with OFF incidence have been the constantly trimmed squirrels and the ones that were almost perfect are the flies like on rails kind

the-plumber

With the L-4, and many other flat-bottomed wing models, power changes generally require a pitch trim change, but of course not always.

These models don't fly like they were on rails, but they do fly very predictably and reliably.

One mod I did use in the L-4 was [link=http://home.mindspring.com/~the-plumber/Models/L-4/Fuselage/pages/07Fuse.htm]this.[/link]

sillyness

My Feedback: (25)

I think most folks in here are talking about symmetrical airfoil aerobatic thoroughbreds, and that's what I'm interested in.

MikeEast

My Feedback: (3)

Hey if you cant use it you cant use it, but its there if you can.

Actually the original design can easily be lengthed/widened to accomodate 40 or 50% or even full scale real aircraft and built a lot lighter IMO and it is intended to be that way. But the fundamental design of the table and use of laser levels will allow you to start out with an absolutely perfectly straight airplane.

Something not in the original plans we talked about the other day was a way to infinitely extend the lasers mounts out so that you could see the laser line along the entire thrustline, leading edges of the wings and stabs all at the same time. I think it could be done with a square aluminum bar mounted to the table that would extend out far enough beyond the wings that the laser would hit everything. You would just have to build in a way to level the bar and raise/lower it as needed.

Panzlflyer

My Feedback: (15)

I generally like to take a new model ARF or otherwise out and I dont expect more than a click or two in trim. If you set it up true or it was built true it will fly true.
Try a 1 degree diference on either stab and see how well it tracks in a loop!! Not to mention tip stalls etc from warped wings.
Note: I'm not talking about Trainers here.

mrbigg

My Feedback: (21)

i'm thinking about the laser incidence meter from great planes. i'm going to need the aluminum extension. is this one better than the robart? if the robart is better, will the great planes extension work with it? i'm building the profile ultimate in the "HUGE ULTIMATE BUILD", over in the profile forums. i want to get everything as perfect as possible. too much time and money invested. i was told to balance the plane so that the thrust line is level and then go from there. is this correct? thanks guys, i appreciate it.

sillyness

My Feedback: (25)

I wound up buying the Great Planes laser meter. I like it pretty well... seems pretty accurate and is eaiser to read than the Robart I looked at. As an added bonus, the plane doesn't have to be perfectly level to use it, it just has to be secure so it doesn't move after you calibrate the meter.

It looks to me like the robart and great-planes bars are interchangable.... that being said I suspect it is a standard bar shape you can find at a hardware store as opposed to paying $20+ for the longer bar. I'll be looking soon.

Josey Wales

My Feedback: (61)

Yep..I got my extended bar at Home Depot..it was 3.50$...Im looking for a new meter so if the bar fits the GP thats what Im gettin

mrbigg

My Feedback: (21)

thanks guys.

p51flier

I never use an incidence meter. I use a ruler and a simple MS Excel sheet. Well, you have to play around with some mathematical functions but this way you get the most accurate results. With this method I also check the amount of washout.

I did use an incidence meter years ago. The major problem for me was the weight of the IM when used at small airplanes (deflection of controll surfaces) and the insufficient length of the IM when used at giant airplanes.

Joe

mrbigg

My Feedback: (21)

i was thinking about the weight of the meter too.

figueroa

My Feedback: (22)

The Great Planes extention bar doenot fit the Robart incidence meter. It's about 1/8 of an inch thicker than the Robart.