stunthanger.com
Speed,Combat,Scale,Racing => Combat => Topic started by: Motorman on August 25, 2018, 09:09:04 PM
-
blank
-
IMO i'd try to isolate the wire from the metal bellcrank - i'd use the straw from a WD40 spray can with wire threaded through it and loop through the crank. It won't preclude the straw wearing through but it will take a while. Harder metal will ALWAYS cut through softer and unless you can engineer an isolated bearing some cutting will occur. Even the usual copper tube loop will wear alloy eventually.
-
I use copper or brass tubing to run the cable through before bending it in the bell crank so it can be wrapped or swaged. Have to anneal the brass tubing with heat so it bends easier. D>K
-
Make the leadout ends with eyelets, just like lines. Bolt the leadouts to the bellcrank with 4-40 blind nut "buttons" and short 4-40 screws.
-
What Bill said.......bellcrank buttons. Available here https://www.mcmaster.com/#90596a005/=zir19n
-
Excuse me being a little bit offtopic, (I write not about FOX bellcrank) but
an essetial principle is by me not to pair metal to metal by any moving connection.
Reason: not only the abrasion counts , but vibration as well, when wearing appears.
So I use always (hard, polished) metal + "self lubricating" plastic pairs. Plastic was in ancient times textile-bakelite (Textolite), and in the recent 18 years ZX-100.
See:
http://www.plasticbearings.com/index.php?id=344&L=2
and here:
https://plus.google.com/photos/117790355930193335731/album/5715088163776972593/5715089525767871586
-
Excuse me being a little bit offtopic, (I write not about FOX bellcrank) but
an essetial principle is by me not to pair metal to metal by any moving connection.
Reason: not only the abrasion counts , but vibration as well, when wearing appears.
So I use always (hard, polished) metal + "self lubricating" plastic pairs. Plastic was in ancient times textile-bakelite (Textolite), and in the recent 18 years ZX-100.
See:
http://www.plasticbearings.com/index.php?id=344&L=2
and here:
https://plus.google.com/photos/117790355930193335731/album/5715088163776972593/5715089525767871586
Most Combat planes will be dead and gone long before a lead out wears though........
-
Most Combat planes will be dead and gone long before a lead out wears though........
This...
-
This...
But not on nostalgia replica's intended to sport fly. I'm still flying replica airplanes of combat planes from the 60's that were built decades ago and have many, many flights on them.
Andre
-
But not on nostalgia replica's intended to sport fly. I'm still flying replica airplanes of combat planes from the 60's that were built decades ago and have many, many flights on them.
Andre
True.
-
Make the leadout ends with eyelets, just like lines. Bolt the leadouts to the bellcrank with 4-40 blind nut "buttons" and short 4-40 screws.
Where did you get the 440 hex head blind nuts?
Al
-
Where did you get the 440 hex head blind nuts?
Al
I make them. Screw a blind nut onto a long 4-40 screw as a handle. "Jam nut" a 4-40 hex nut against the top of the blind nut, and grind the blind nut down to match the hex nut with a moto tool and cutoff wheel. The result is a 1/4" hex button. If you want a 5/16 hex button, use a 4-40 weld nut from McMaster Carr, and buy one of their 4-40 rod couplers, which is a 5/16 hex threaded standoff kind of thing. The weld nuts are like blind nuts before the teeth are formed. They make good round buttons as supplied. I also use the large eyelets from Brodak or MBS Model Supply.
-
Im building a Voodoo type wing can I use piano wire with 80 to 100# Strength. Thanks
-
Take it from experience from many, many years ago, stay with cable lead outs. D>K
-
Never worried about bushing a bellcrank on a combat type ship or a racing plane for that matter. The combat planes did not last that long and the racing planes do not have the constant full movement so the braded leadout on racing planes lasts for years.
-
I still have 40 year old bell cranks that I ran just cables through. Some wear can be seen but never enough to not re use.
-
FAST combat new style or old skool Big Iron , Raunchy, VooDoo, Equalizer, or all others with inside wing BC.....
Most competitive Fast Big Block combat is flown with foam wings and top side BC and fuel cuts... yes there is/ are lot of East Europe made ARFs with internal controls
Top side BCs are usually best with Buttons and line lengths in regulation Eyelet to eyelet of 60' +/-6"
In my opinion old skool for nostalgie craft that might not ever see for than 50 flights ever...who cares....
we have plenty of historical facts that aluminum or nylon Bell cranks do NOT cut the solid or stranded lead-outs....rather the Bell Crank or Horns wear and do get sloppy...crap there dozens of photos of this wear here on SH in the Brett Buck sandwich Bell Crank threads
on the other hand the effort and practice to make the lead out to Bell Crank interface most long lived and least drag...copper tube and 7 strand stainless .037 with adjustable guides is not hard to fabricate
-
I use copper or brass tubing to run the cable through before bending it in the bell crank so it can be wrapped or swaged. Have to anneal the brass tubing with heat so it bends easier. D>K
Me too. I used .027" cable for 36-size and .018" cable (broken lines) for FAI.
They always outlived the models and got installed in the new model, leadout guides and all.
The bending of the annealed tube into a horseshoe shape tended to slightly crush the tube, thereby relieving some, or maybe all, the stress on the termination.