Guts of a 3-line Handle?

[Tim Wescott]

Does anyone have a picture of the guts of a three-line control handle?  I seem to be unable to convince myself that it makes more sense to spend $75 for a handle and bellcrank from Brodak than to spend $500 worth of my time making something from scratch.

I can figure out the bellcrank without too much difficulty, and a few ways to make the handle.  But it'd be nice to know "how it's done".

[50+AirYears]

This might be of some help.  It's from an old 1994 Model Builder magazine.  Hopefully, the attatchment will work.

Whoops, seems the files are a bit too large.  I'm going to have to do some editing.  I'll try again later.

[Rob Killick]

Nope ,

No workey 

[Joe Just]

Here is an inexpensive way to fly with 3-lines. I have sold or given away 40 some of these in the past 2 years. Really work well for .15 to .36 size Carrier or sport planes. Send me your mailing address and I will get one out to you for mailing cost when I get back to WA after 10 days in NY State.

Joe

[50+AirYears]

I don't give up easy.

[50+AirYears]

I'm feeling lucky.  Let's see if I can include the rest of the article.

[Paul Smith]

I've looked inside the plastic clading and found a factory-assembled unit that discourged further disassembly.

To get true "J.Roberts" action, the mechanism needs to over the UpDown lines in and out together and also move the gas pedal the opposite way so as to balance line pull at all times.  Unless you are really well-equipped, you're a lot better off paying the $55 price tag.  They were $20 42 years ago, not a bad inflation rate.

[50+AirYears]

Yah, the Model Builder photo shows a nice articulated double arm linked to the tthrottle slider to get the motion reverser.  The position of the two pivots in relation to the line attachments and the link connections may or may not be critical.

[Joe Just]

Tim, got your PM, but i can not answer any PM's. I still need your mailing address for the free han dle.  Please send it to me as a PM and i will get one on its way to you by Tuesday before leaving for Buffalo.
Joe

[john e. holliday]

I still have my first J-Roberts handle.   All of $9.95  and I think $1.95 for the bell crank assembly.  Joe's handle set up is great for 15 carrier and sport carrier as long as the pull is not too great.  Would not even attempt it in a high powered scale carrier.   

[Tim Wescott]

Tony:

Thanks for posting that.  After I posted my question I tried One More Search and found a page from England or Australia that shows how to make about 1/2 the J-Roberts style handle -- it basically leaves the throttle lever in the middle of the handle, rather than the end.  So instead of having the extra lever in the J Roberts handle that brings the throttle up to your index finger, it leaves you working the throttle with your 2nd and ring fingers (not me, though -- I don't have enough independent motion between my ring finger and my pinky to pull it off).

Paul:

I already said it didn't make sense -- and yes, I've got a fairly well equipped metal shop here, so I can fabricate anything up to and including an exact reproduction of the J Roberts handle if I want to take the time.

Tony:

Yes, the relationship between the pivots is important -- if you start by saying that the line tension must be consistent and that the throttle and elevator actions are not to interact, then the math says that for every 2mm the throttle moves out the up and down lines each have to move 1mm in.  This relationship has to be maintained at both the plane and the handle, otherwise either you will feel variations of line tension on your throttle finger (which is the drawback of the cool-because-it-is-simple handle that Joe is offering) or you will have some interaction between throttle and elevator action.

[Joe Just]

Tim, Your free handle and bellcrank go out Monday AM from Waitsburg,WA.  Hope it works well for you.
Joe

[50+AirYears]

I've found with mine that the ability to get full throttle movement requires that the handle and bellcrank movement be closely matched.  Also means you have to be very precise in setting up the  plane leadouts.  I remember reading somewhere that the current (Brodack?) handle may have a slightly different degree of movement than the original Robert's handle.  I know I've only had one plane that gave me nearly full range.

I think I've seen the mating of the two regular bellcranks, and the single pivot handle since sometime in the early 60s.

I also have a file copy of a similar non-enclosed articulated linkage handle from Aero Modeler, and English Publication.

And here's a blurb on setting up one of the systems.  Thought it was interesting just how accurate you need to be in setting thee systems up.  Hope this is useful.

Interesting that in 1981, MAN was still a model aviation orientedmag, and not just an RC ARF catalogue like it now seems to be.

[john e. holliday]

Yes you have to take the time to make sure the lines are the proper length.  I have seen leadouts tied where they were the same length.  The same with the handle.  Even then you still need to tie each line accordingly and mark them.  I use two reels glued together.  One gets the throttle line and the other the elevation lines.  The up clip/connector stay on the airplane.   And you should need or have a dedicated set of lines for each airplane.  I used one handle on all planes for years.

Now for minor adjustments to the throttle control on the plane.  I use a transfer bellcrank or lever.  There is a pushrod from the bellcrank throttle to the transfer crank.  Then another pushrod from it to the throttle.  Just like the control horn you move the pushrod for the control action needed.  If you look thru my posts over in the carrier section you find a picture of my throttle set ups on the SkyRay and a throttled profile Stuka by John Lowrey.  Remember it takes patience and thought to set up and once setup don't let a pit boss make you change it.