estimating height and distance gadgets ?

[tipperary]

Any smart and simple way of estimating height and distance like some form of gadget you can hold up ? Like a striped thumb ?

[vintage1]

Yup. You need a theodolite.
One with scribed circdles on it showing angle subtended..

Look at model, point it towards you, and read off angle subtended by wingspan and angle of theodolite above horizon.

Get nerd to do tricky maths and tell you how far ...span/tan (sunbtended angle angle)..and how high ..distance x sin(azimuth)..and how far away in ground term - subsitute cos for sine...

[Tom Harper]

1. Put black tape strips on a pair of sunglasses.

2. White paint on the underside of your cap bill.

3. (Preferred) calibrate the first joint and nail of your thumb.

The airplane is moving too fast for gadgetry

[coosbaylumber]

Back about two years ago, there was a firm located in New Mexico who was pushing some software. It was based on recreating automobile accidents. Some ingenious modeler figured out a way that he could step up to a real A/C take pictures of it, and the software devised a 3-D representation of it. He then found several old B&W pictures of an A/C that no longer exists, and he used about six of them to again make up a 3-D model of it. He then used the accident software and imported it into some 3-D CAD software and developed plans.

I can't estimate all the time involved in this effort, as he did not state. The accident software was selling for $100 in the time before Windows XP was out and I cannot remember what 3-D software he was using, but mentioned the results went into some Autodesk product available at the time.

Big talk is now that 3-D scanners are getting more affordable and can be used on a simple home/office computer.

Wm.

[Sparky Paul]

For distance, this works..

[Arthur P.]

Alternatives:

Relatively simple:
Put a camera in the plane. Before doing that, however, determine the magnification of lens (e.g. calibrate the lens to a number of objects of known size and distance relative to their size in pixels in the image). Take a picture while flying. Look at an object of known size in the image and determine the number of pixels it takes up. This allows you to estimate the distance to that object. If the picture was taken straight down and the object was in the middle, the distance will equate to the height of the camera at the time the picture was taken.

More advanced:
Put one of those flightlog gadgets in the model. Post-flight you can graph altitute (and speed and direction??).

Most advanced:
Put one of those flightlog gadgets AND/OR a GPS receiver (which if standalone also logs the measurements) in the model. Postflight you can graph both the flightpath overt the map and the altitude. For each point of the flight you can calculate the distance horizontally or in direct line to the point of origin (or any other point).

The first solution is simple, not very accurate, but lots of fun in the pictures returned. Have a look in the Aerial Photography forum... The other two are a function of bucks and/or size of plane.

[Tom Harper]

Sparkster,

Now that makes sense - the thing is right in front of your face anyway!

[JRuggiero]

Get an optical golf distance measurer, which measures the distance from the viewer to the flagstick (pin). It assumes a standard golf flagstick height of 7 feet, less maybe 6 inches in the hole. That leaves 6 feet and 6 inches of flagstick above ground. That's darned close to 2 meters, the span of a typical sport sailplane.

Assuming your airplane is a 2-meter sailplane, position it directly overhead, then view it with the optical gadget. Distance can be read to 1000 yards, sometimes. These gadgets sometimes cost $35 US, sometimes $250 US.

Or go to shops that sell used cameras and look for a split-image rangefinder. Federal used to make one. Distance between viewing ports was about 8 inches, so measurement could be made to 250 yards, irrespective of airplane size.

Jim R

[A.T.]

Suggest you read =
Don't Color Me Gone
by Dr. Robert Suding
http://www.ultimatecharger.com/color.html

and the other URL on covering & colour etc at =
http://homepages.ihug.co.nz/~atong/

Note that "Invasion stripes" are the most visible form of judging
distances.
On a light coloured wing and use black paint or 2cm wide black vinyl tape
and put two bands across the top of each wing about 3/4 out with a
separation of same width between the bands - these will be seen as separate
bands by different people at 120-240m out (400-800') after which they form
a solid band - most people have good stereoscopic vision to 300m. (1 cm band should allow upto 60m (200')
By putting your model on a stand or ask a friend to hold in banked
position, walk away and measure distance at which lines are seen by you to merge, then adjust width of the bands to allow for maximum required distance so as not to pass within say 50 feet of the trees. FWIW most of my models use this feature so as to ensure I keep large models within range.

regards
Alan T.
http://homepages.ihug.co.nz/~atong/