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Old Apr 03, 2013, 06:56 PM
Phil.T-tailer
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The Mad-stab Mad-AMT MadStab design resource thread

Starting a thread here to collect together links to all the ideas that inventive folks on here have come up with for Mad-stab / Mad-AMT - mechanics, linkages, pulleys, cams, chain drives etc.

I'll start with Dawson's oval pulley:
http://www.rcgroups.com/forums/showthread.php?t=1693398

Please add any other links that you know of - so we can build a "design resource"
here for future easy reference

and heres a big "thank you" to all the inventors / experimenters / evolutionists that have got us this far

(and yes, I need this so I can build oval pulleys etc. for the Kulbutin refurb !)

Phil.
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Old Apr 03, 2013, 07:01 PM
Phil.T-tailer
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Shane's funky hybrid pushrod/pulley system on the Fluid:

http://www.rcgroups.com/forums/showp...&postcount=141
http://www.rcgroups.com/forums/showp...&postcount=168
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Old Apr 03, 2013, 07:04 PM
Phil.T-tailer
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I'll contribute my Kulbutin removable Mad-AMT design

http://www.rcgroups.com/forums/showp...21&postcount=9
http://www.rcgroups.com/forums/showp...6&postcount=30
http://www.rcgroups.com/forums/showp...4&postcount=32
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Old Apr 03, 2013, 07:08 PM
Feeling FrSky
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For the ultralight Le Fish, I am using a copy of Benoit Paysant-Le Roux's elevator layout as shown on the Madslide plan, with small changes as follows:
  • 6mm Depron (or EPP) for the elevator surfaces
  • 0.125" / 3.2mm carbon fiber tube for stabilizer spar / joiner (CSTSales.com Part Number T512)
  • K & S Tubing 5/32" (3.9mm) x 0.014" (0.35mm) wall aluminum or brass tubing for pivot bearing - perfect sleeve with above CF tube
  • Du-Bro #846 Micro Pull-Pull System with tailboom-mounted elevator servo
  • 1/32" or similar thickness plywood, fiberglass or carbon fiber plate to "box-in" the pivot bearing tube - super bomber mod that greatly increases durability of this joint.

I'm currently using a Futaba 3156MG servo for the elevator, but this is the third one in my plane in about 6 weeks - they're dying early deaths as they do not appreciate any sort of abuse whatsoever.

I recommend instead a Hitec HS-65MG, but you'll need a longer servo arm - Du-Bro #934 Micro Servo Arm XL for Hitec looks good.

I have no affiliation with any of the above companies, just find their products work for this application. Feel free to substitute as appropriate.

Steve
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Old Apr 03, 2013, 07:09 PM
Phil.T-tailer
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and the great-grand-daddy of them all - the original Madslide pull-pull system

http://www.jivaro-models.org/madslide/page_madslide.htm

EDIT - HaHa - Steve beat me to it - its all good

Phil.
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Old Apr 03, 2013, 07:23 PM
Phil.T-tailer
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Francois Cahour's interesting offset pulley/cam design for the mid-mounted removeable Mad-AMT on his Quartz

http://www.rcpilot-online.com/fcahou...r-3D_a102.html
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Old Apr 04, 2013, 06:29 PM
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any more contributions? - or just Steve?

Phil.
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Old Apr 04, 2013, 07:15 PM
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Here is another method I'm using on my BD-5. A Mad Whip. In the center of movement, the system acts like it is on low rates. When the servo moves far enough, the whip takes over and moves to very high rates to get the 90 degree tail movement...kind of a mechanical dual rates.

I'm working out 90 degrees for both up and down with this system. The nice thing about the whip is that you don't have to switch anything on the TX. Fine control in the middle of the stick then full up elevator in the last bit of stick movement.

Mad Whip on my Le Fish.
Mechanical dual rate for Mad Stab (0 min 34 sec)
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Old Apr 04, 2013, 08:55 PM
Feeling FrSky
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Towards a durable, packable Madstab

I've been brainstorming this solution for a packable Madstab for some time, and plan to build a prototype as soon as I get the parts together.

It's comprised of five parts:
  • 3.9mm square CF joiner rod
  • 6mm square (4mm inner) CF capture tube with corners rounded off
  • 11/32" brass inner bearing tube (0.014" wall)
  • 3/8" brass outer bearing tube (0.014" wall)
  • Control horn or pulley bonded to capture tube

The concept is pretty simple, the 6mm square capture tube (4mm square inside) is installed in the stab halves, as well as having a section bonded to both the inner bearing tube as well as the control horn or pulley (the corners of the bearing tube will have to be rounded off to get it to sleeve into the 11/32" inner bearing tube).

That subassembly is then sleeved inside the outer 3/8" bearing tube, which is installed into the plane with ply or CF/FG plates supporting either side.

A single 3.9mm square joiner rod is used to join the stab halves together. Friction alone might be sufficient to retain the stab halves, if not, then I'd use four small neodymium magnets at the ends of the joiner rod and capture tubes to keep everything in place.

In theory, it should work. In practice... we'll just have to see!

Steve

In theory this should work pretty good... in practice, who knows!
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Old Apr 05, 2013, 02:51 AM
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Would this work? A 180-degree servo shaft directly on elevator fulcrum.
Here is a 180 degree servo: http://www.hobbyking.com/hobbyking/s..._12g_0_10.html

No, that won't work.
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Old Apr 05, 2013, 06:51 AM
Phil.T-tailer
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Quote:
Originally Posted by surfimp View Post
I've been brainstorming this solution for a packable Madstab for some time, and plan to build a prototype as soon as I get the parts together.
In theory, it should work. In practice... we'll just have to see!

Steve
Good thinking & sketching there Steve - sort of a fully packable version of the Kulbutin square-drive.
When I was building the Voltij (5 years ago now!) - I got as far as raiding the K&S metals rack at the LMS - I came up with square brass tubes which fitted into each other. But then the Kulbutin turned up so I built the Voltij tail "stock"
A potential problem is slop from the square joiner being able to rotate slightly in the square tube - might not be a problem for a lightweight ultrabat. Bigger square or rectangle (!) drive would have less slop. Build one & try it out?

Phil.
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Old Apr 05, 2013, 09:24 AM
Feeling FrSky
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Quote:
Originally Posted by Phil.Taylor View Post
A potential problem is slop from the square joiner being able to rotate slightly in the square tube - might not be a problem for a lightweight ultrabat. Bigger square or rectangle (!) drive would have less slop. Build one & try it out?
Yes, I am concerned about the slop you mention although I do have some ideas around how to address it. But to you point, yes again, I intend to use one of these in the near future on a build

Steve
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Old Apr 05, 2013, 09:41 AM
Feeling FrSky
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Quote:
Originally Posted by Phil.Taylor View Post
As far as I know, this idea originally came from Vincent "Prop-er" with his Twincam setup used on the Slopium prototype he built about a year ago.

Here is his video demonstrating its workings:

DSCN6138.MOV (0 min 48 sec)


And on the tail of the plane - check the sweet taileron action!

Madcam system (0 min 57 sec)


And the beautiful Slopium itself:



Steve
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Old Apr 05, 2013, 09:46 AM
Feeling FrSky
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Another cool design idea which uses the concept of spring tension - similar in general principle to Dan "Leadfeather"'s solution but totally different in implementation - is the 2PES - 2 Point Exponential System - by Stéphane "pgts" Combet:

2PES - 2 Point Exponential System - for madstab. (2 min 9 sec)


Stéphane is the creator of the RC-SlopeS as well as the designer of The Poisson, a Depron ultrabat inspired in part by Le Fish. He is currently in progress on a very cool all-wood ultrabatic plane called the Snowflak, which will put the 2PES system into practical application.

SNOWFLAK - I would like to mix a snowflake with a Lunak as RC-glider... (2 min 10 sec)


Steve
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Old Apr 05, 2013, 12:51 PM
FSD
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Great thread...well needed.

-Paige
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Last edited by FSD; Apr 05, 2013 at 02:12 PM.
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