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quick update:
Have added H21A1 optointerrupters for the main ring gears. Had to be careful that the flag had a full range of movement, and still not convinced the flag on the compass card won't cause some problems with the 7-segment displays and off flag mechanisms.
Also added cutouts for the glideslope indicators, and mounted servos in positions that might work. Am using 0.5" and 1.5" spacers as used in BSAI.
http://mycockpit.org/forums/images/HSI/hsi03.jpg
Ok, Lets move the optical sensors to the opposite corner because the rotary encoders need to go where you have them now. (or just rotate the picture..)
Since this is a combo unit that fits many planes, I guess we can lose the outer facia ring that the BK unit has.
Now if you please, add the encoders and the 7 seg displays in the corners. That way we will know if the proper clearance exists or if we need to modify the ring flags with a greater bend.
Can we get a detail shot of how you have the inner servo connected at this point?
This is looking good. I imagine there are a few out there ready to build as we design. :D
Hmmm... If we add just a squidge of space between the rings, do you think we could fit the opto-interrupters between them? That way they do not interfere with the encoders or the 7 seg displays.
My largest Simkits instrument is about 5" deep, so we have plenty of room yet.
Ruprecht:
Love ya work mate! Here's a suggestion for the optos. If we drill a hole in each ring gear the optos can be moved up to straddle the gears and save some space.
Another practical consideration as far as the materials for the gears. Consider the standard thicknesses of metals. I'm not sure what the thicknesses are for brass (expensive in the sizes needed) but aluminum (aluminium for the Aussies watching) cover a pretty wide spectrum. 3mm is a nice thickness to work with but I've made gears successfully from thinner stuff.
The problem with thinner stuff will be the attachment of the bug and course pointers. As it appears in your diagrams, it looks like you've attached them to the inside edge of the gears. We might be able to make a tab on them and fold them and attach them to the face of the gear, but that adds thickness to the gear which needs to be accounted for, as far as the optos are concerned.
One more practical consideration, we'll be home building these, so try not to make the tolerances/clearances too tight. That makes them really hard to build.
Lastly (for now) for rotating bearings or concentric shafts, it's hard to go past the little brass tubes that you get in the hobby stores. I'm not really familiar with the sizes of the metric ones, but the imperial ones go from 1/16" upwards at 1/32" intervals and the slide inside one another very nicely and freely with minimal play or wobble. The wall thicknesses are just under 1/64".
Keep going mate your drawings are looking fantastic. I myself would prefer the BK style, but hopefully we'll be able to mod your mechanicals to suit the different style.
Guys:
I just had an idea for mounting the ring gears. Imagine the ring gears meshed with 4 small gears of the same thickness as the ring gear. Imagine these small gears positioned at 90 degree intervals (even three at 120 degree intervals would do). Now imagine that each of these gears rotates freely on a fixed shaft mounted to it's plate, but most importantly...Each small gear has a washer on both sides of it that overlaps the ring gear thus retaining the ring gear while the little gear acts as a bearing.
HA! Thanks Scott! I had that idea for drilling the hole the other day but as usual, my grandaughter chose that moment to ambush me. Apparently I have 'Climb on and beat on me' tattooed somewhere on me. So, thanks to her, I had forgotten that one. And the layered gear idea I had was a rather complex method of always knowing the exact position of the gear.
EDIT: I like the three at 120 better. Just as sturdy and less to build. So the washer is basicly a bushing to keep the spacing correct.
Roger that and less gears to cut. ;)
The washer is a spacer and retainer.
Is this what you meant by the support gears? The washers are standard steel off the shelf, and the shafts are 1/8" and 3/32" brass tubing. The gear is a 12-tooth.
http://mycockpit.org/forums/images/H...tingGear02.jpg
Guys, keep up the great work. You are making history as you progress here.
Thanks Trevor.
Guys, while I focus on the modelling (around my day job and other pitbuilding activities!) it would be very helpful if you could collect standard dimensions for the components we will be using. Things I'm thinking of are:
- rotary encoders
- 7 seg displays
- sheet metal
- LEDs
etc, anything you can think of. I am working in mm to 3 decimal places. Remember, use commonly available stuff, not random stuff from your "bits box".
cheers lads