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***CUB BROTHERHOOD***

Old 02-25-2014, 01:46 PM
  #1801  
John_M_
 
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Thanks Steve... the cap is 11/16 of an inch in diameter which represents 2.75" inches full scale... I think the full scale is closer to 3"; but the PL259 looks close enough.

And my mind continues to wonder... I was thinking about animating the control stick in the cockpit by using some pull pull cable out the side of the fuse and along the forward strut, around a working pulley and connected to the servos in the wing... for safety, adding a lite weight spring inline on the cable inside the wing to protect the servos in case of any binding that may occur... but that all depends on how much weight I have added so far.


John M,
Old 02-25-2014, 02:00 PM
  #1802  
FlyerInOKC
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On Tail Wheels I like to run the cable/rod thru an E-Z connector mounted on servo arm with a lite spring on each side and the a small collar to sandwich the spring between them and the E-Z connector. It prevents unwanted movement due to rough surfaces damaging the servo. You can make your own or get a kit from Great Planes: "GPMQ3890 Spring Over-Ride Servo Saver". It cost between $2 and $3 is all.
Old 02-25-2014, 02:14 PM
  #1803  
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Good idea FlyerInOKC... I forgot about those... I use to use something like that on my throttle servo before they had computer radios with end point adjustments... I'd get the travel as close to proportion with the mechanical linkage, and use the spring to take up any binding / over travel.


John M,
Old 02-25-2014, 02:42 PM
  #1804  
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John,
I wouldn't worry about the weight. I think that big wing can handle it.
Nice fuel dot too.
Old 02-25-2014, 02:48 PM
  #1805  
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Here's the old J3 stripped down. A 10 meter roll of Solartex just hit the door
so I am about ready to do it to it.
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Old 02-26-2014, 06:36 AM
  #1806  
FlyerInOKC
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Originally Posted by John_M_
Good idea FlyerInOKC... I forgot about those... I use to use something like that on my throttle servo before they had computer radios with end point adjustments... I'd get the travel as close to proportion with the mechanical linkage, and use the spring to take up any binding / over travel.
John M,
Us old fossils remember stuff like that.
Old 02-26-2014, 06:40 AM
  #1807  
FlyerInOKC
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Originally Posted by cubcrasher
Here's the old J3 stripped down. A 10 meter roll of Solartex just hit the door
so I am about ready to do it to it.
If that is bright yellow interior I would say it looks like the old Ultracote paint I used on my Cub's interior. I covered the exterior with Bright Yellow Ultracote and painted the cowling and the interior with the matching paint. The cowling came out great on the color match after I used a white primer.
Old 02-26-2014, 06:57 AM
  #1808  
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Originally Posted by John_M_
Good idea FlyerInOKC... I forgot about those... I use to use something like that on my throttle servo before they had computer radios with end point adjustments... I'd get the travel as close to proportion with the mechanical linkage, and use the spring to take up any binding / over travel.

John M,
When coupling my tailwheel tiller arm to either the rudder or to pull-pull cable, I use a spring arrangement much like the FS Cub. I bend .035 music wire into a "U" shape and then put small hooks at each end. using one of these inserted into each end of a compression spring (from a ballpoint pen if the size is right) I then hook the rudder tiller arm or the pull-pull cables to one end of the "spring" assembly on each side and the other ends to the tiller arm on the tailwheel. Sounds complicated, but is not hard to do and like the FS assembly is failsafe and cannot overstretch. Not inventing the wheel, just reducing the size to our needs.

As a further aid, I use an on-board voltage monitor. Anytime a servo is at limit or something is binding, the voltage monitor will drop into the red zone indicating a voltage drop due to the stall or bind. I can then fix the issue before the first flight or before every flight.
Old 02-26-2014, 06:59 AM
  #1809  
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Flyer,
That is actually Nelson Hobby Paint.
I've been redoing the landing gear. After I get back from town I am going to paint
the interior light gray. Then lay on the Solartex. If any of the wood grain shows through
I am going to put some acrylic enamel on top. I have been lucky with this plane, 10 years
of flying it and no crashes. That said I will probably pile drive it after it is done.
Old 02-26-2014, 07:05 AM
  #1810  
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Spaceworm,
I like that idea. I've got a small brain though. Could you post
a pict?
Old 02-26-2014, 01:23 PM
  #1811  
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Originally Posted by cubcrasher
Flyer,
That is actually Nelson Hobby Paint.
I've been redoing the landing gear. After I get back from town I am going to paint
the interior light gray. Then lay on the Solartex. If any of the wood grain shows through
I am going to put some acrylic enamel on top. I have been lucky with this plane, 10 years
of flying it and no crashes. That said I will probably pile drive it after it is done.

Shhhhhhh, don't say that. LOL
Old 02-26-2014, 01:56 PM
  #1812  
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Originally Posted by spaceworm
When coupling my tailwheel tiller arm to either the rudder or to pull-pull cable, I use a spring arrangement much like the FS Cub. I bend .035 music wire into a "U" shape and then put small hooks at each end. using one of these inserted into each end of a compression spring (from a ballpoint pen if the size is right) I then hook the rudder tiller arm or the pull-pull cables to one end of the "spring" assembly on each side and the other ends to the tiller arm on the tailwheel. Sounds complicated, but is not hard to do and like the FS assembly is failsafe and cannot overstretch. Not inventing the wheel, just reducing the size to our needs.As a further aid, I use an on-board voltage monitor. Anytime a servo is at limit or something is binding, the voltage monitor will drop into the red zone indicating a voltage drop due to the stall or bind. I can then fix the issue before the first flight or before every flight.
That's another good idea; the springs are always in compression rather than stretching... you would never over stress the springs using your method.

The idea of having the springs inline was just in case binding occur with the animated control stick in the cockpit during flight... that's all it would take to bring it down in a bad way... if binding did occur, the aileron servos would continue to move the ailerons... the chances of binding occurring are slim, but its cheap insurance, just in case.

Did I mention that Murphy (law) and I go way back... he and I crossed paths too often to be a coincidence lol

John M,

Last edited by John_M_; 02-26-2014 at 02:07 PM.
Old 02-26-2014, 02:06 PM
  #1813  
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Originally Posted by FlyerInOKC
Us old fossils remember stuff like that.
LoL... never thought of myself as a fossil; more like petrified wood, but yeah, one in the same; old as dirt, lol

The ol mechanical mixers, what a treat those were to set up ... those were the days we used "whatever works methods" to get things done.


John M,
Old 02-26-2014, 02:15 PM
  #1814  
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Originally Posted by cubcrasher
John,I wouldn't worry about the weight. I think that big wing can handle it.Nice fuel dot too.
Yep, the wing is strong; I just don't want to be under powered... I don't think I'll be adding much more than a couple pounds... the biggest weight contributors are the robart landing gear and the H9 struts... everything else is small stuff, shouldn't add that much weight.


John M,
Old 02-27-2014, 07:00 AM
  #1815  
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I still have a manual from MAN on setting up mechanical control systems. Most of it we don't really use anymore but its just too good to throw away. Its like the tiny Aeromodeling hardback (4" X 12") I have from the late 50s-early 60s. Its trying to fall apart and to call it dogeared is a complement but some of theoretical stuff still applies today.
Old 02-27-2014, 09:35 AM
  #1816  
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Originally Posted by cubcrasher
Spaceworm,
I like that idea. I've got a small brain though. Could you post
a pict?
It works on the same principle as this device which those of us from windy climates will recognize...



mnem
*Nods knowingly*
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Old 02-27-2014, 10:04 AM
  #1817  
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Here is a better view of what I think he is talking about.
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Old 02-27-2014, 01:28 PM
  #1818  
rafeeki
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Default Working landing gear

This is what I did with my 1/5 scale Cub..

Rafeek
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Old 02-27-2014, 02:16 PM
  #1819  
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Originally Posted by FlyerInOKC
Here is a better view of what I think he is talking about.
Yes, that is it, just make the hooked pieces out of music wire and use a compression spring to suit. Thanks, saves me trying to draw it.
Old 02-27-2014, 02:36 PM
  #1820  
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A small piece of 1/4ply and three dowels make a nice jig for consistent duplication.
Old 02-27-2014, 09:44 PM
  #1821  
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Wink

hey guys, havnt posted in a while but have been keeping up with everyone
ive been re-doing an old goldberg cub. heres a couple pics for now. i also
built a matching set of floats for it. hopeing to maiden this weekend on its
wheels the next. its powerd by a saito 65GK fs. will post pics asap on the floats
Happy Flyin and Buildin,
TY
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Old 02-27-2014, 11:31 PM
  #1822  
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Nice one dirtrod.
Old 02-28-2014, 06:21 AM
  #1823  
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Originally Posted by cubcrasher
Nice one dirtrod.
+1

You're welcome Spaceworm. I saw the drawing someone posted and recognized it as a storm door safety chain so it was easy to find. I was in the home improvement business at one time, you would be surprised how many doors have been saved by those springs.

Last edited by FlyerInOKC; 02-28-2014 at 06:24 AM.
Old 02-28-2014, 06:58 AM
  #1824  
mnemennth
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*Putters quietly in the corner*


mnem
"If you can't say it quietly, it probably isn't worth saying."
Old 02-28-2014, 03:05 PM
  #1825  
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Originally Posted by mnemennth
*Putters quietly in the corner*


mnem
"If you can't say it quietly, it probably isn't worth saying."
Kinda like a four stroke just barely ticking over?

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