Author Topic: making logarithmic controls (Read 6243 times)

Igor Burger · « **on:** June 10, 2014, 01:39:17 AM »

Several people asked about making my logarithmic controlls. Most pictures are also on facebook, but for those not having account there, I will make thread about making controlls and how I build them in model also here. The first picture shows steel parts. They are new, while following pictures shows older parts, so do not be confused with little different look.

Openings are little bit undersized, so it will need little work with a file to make proper fit, especially for no-gap and no friction ball bearing fit in slot.

Igor Burger · « **Reply #1 on:** June 10, 2014, 01:49:49 AM »

Making horns. I use brass tubing and soft steel 1/8" rods. Soldered with Ag4SN96. I think pictures tell all. If not, ask.

EDIT:
I wrote it in messages, but I think it should be here:
That shiny wire is silver plated brass or copper wire (I am not sure, it is from hobby shop for decoration).
The rod is copper plated soft steel (therefore that color).
Those materials perfectly soak melted AgSn solder with water based soldering flux for copper tubing (white gel stuff).

Igor Burger · « **Reply #2 on:** June 10, 2014, 01:52:26 AM »

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Igor Burger · « **Reply #3 on:** June 10, 2014, 01:53:51 AM »

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Igor Burger · « **Reply #4 on:** June 10, 2014, 01:54:51 AM »

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Igor Burger · « **Reply #5 on:** June 10, 2014, 01:57:30 AM »

hole for push rod is then dilled or filed for proper pushrod fit after soldering

Igor Burger · « **Reply #6 on:** June 10, 2014, 02:02:02 AM »

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Igor Burger · « **Reply #7 on:** June 10, 2014, 02:05:19 AM »

making logarithmic bellcrank ... drilled nut is for better stability

Igor Burger · « **Reply #8 on:** June 10, 2014, 02:06:51 AM »

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Igor Burger · « **Reply #9 on:** June 10, 2014, 02:11:19 AM »

classic main bellcrank is done the same way

Igor Burger · « **Reply #10 on:** June 10, 2014, 02:13:24 AM »

push rods

Igor Burger · « **Reply #11 on:** June 10, 2014, 02:15:14 AM »

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Igor Burger · « **Reply #12 on:** June 10, 2014, 02:16:23 AM »

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Igor Burger · « **Reply #13 on:** June 10, 2014, 02:21:09 AM »

installation in fuselage

Igor Burger · « **Reply #14 on:** June 10, 2014, 02:22:46 AM »

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Larry Fruits · « **Reply #15 on:** June 10, 2014, 05:23:11 AM »

Thanks Igor. Great tutorial.

Larry

Derek Barry · « **Reply #16 on:** June 10, 2014, 06:28:47 AM »

Hello Igor,

What is the benefit of your logarithmic controls?

Thanks
Derek

Crist Rigotti · « **Reply #17 on:** June 10, 2014, 07:48:09 AM »

Beautiful Igor! Thank you.

Derek Barry · « **Reply #18 on:** June 10, 2014, 08:54:42 AM »

Quote from: Crist Rigotti on June 10, 2014, 07:48:09 AM

Beautiful Igor! Thank you.

No doubt! His workmanship is incredible.

Derek

Allan Perret · « **Reply #19 on:** June 10, 2014, 01:03:04 PM »

Igor, how do you make the bends on the control horns so close to the bushing tubes without distorting them ?
Do you have a picture of the tool or jigging you use ?

Tim Wescott · « **Reply #20 on:** June 10, 2014, 01:13:30 PM »

Quote from: Allan Perret on June 10, 2014, 01:03:04 PM

Igor, how do you make the bends on the control horns so close to the bushing tubes without distorting them ?
Do you have a picture of the tool or jigging you use ?

Don't you mean control rods? If you look closely at the rod in the vise, it's in a tube.

Also, the rods look to be brass and not steel, which would tend to make them more malleable.

Igor Burger · « **Reply #21 on:** June 10, 2014, 01:34:55 PM »

Thanks guys :- ))

Derek: it helps to make rounds round and squares square :- ))))

Tim: no it is not brass, it is soft steel rod. (not hardened, no piano wire, simply soft steel)

Allan, the brass tubes are tight on rods without notable free play, so it is easily fixable and soft steel will bend easily. You can see clearly part of untouched metal segment (which was in tube and fixed during bending) and bent segment with clearly to see plastic deformation on those hooks for pushrods as Tim mentioned. It works nice. I add few more pictures showing just what you asked.

Igor Burger · « **Reply #22 on:** June 10, 2014, 01:36:46 PM »

may be this is even better visible

Allan Perret · « **Reply #23 on:** June 10, 2014, 01:47:10 PM »

Quote from: Igor Burger on June 10, 2014, 01:34:55 PM

Allan, the brass tubes are tight on rods without notable free play, so it is easily fixable and soft steel will bend easily. You can see clearly part of untouched metal segment (which was in tube and fixed during bending) and bent segment with clearly to see plastic deformation on those hooks for pushrods as Tim mentioned. It works nice. I add few more pictures showing just what you asked.

I was thinking that just using a regular vise would have caused enough distortion on the bushings that they would no longer turn free on the horn wire. I guess the difference is you use a softer wire which bends with much less force than I am accustom to with bending harder wires.

Igor Burger · « **Reply #24 on:** June 10, 2014, 01:51:58 PM »

And yet more informations - that shiny wire is silver plated brass or copper wire (I am not sure, it is from hobby shop for decoration). Mentioned rod is copper plated steel (therefore that color). Those materials perfectly soak melted AgSn solder with water based soldering flux for copper tubing (white gel stuff). Therefore it makes so pretty joints. And do not worry about soft solder strength, I tested one horn and picture shows that join is stronger then rod itself.

Igor Burger · « **Reply #25 on:** June 10, 2014, 01:54:04 PM »

Quote from: Allan Perret on June 10, 2014, 01:47:10 PM

I was thinking that just using a regular vise would have caused enough distortion on the bushings that they would no longer turn free on the horn wire. I guess the difference is you use a softer wire which bends with much less force than I am accustom to with bending harder wires.

Yes I think so ... however fixing in wood does not work well, it will allow rod to bend inside the tube and then it does just what you described. Guess how I know :- )))

Derek Barry · « **Reply #26 on:** June 10, 2014, 02:10:51 PM »

Quote from: Igor Burger on June 10, 2014, 01:34:55 PM

Derek: it helps to make rounds round and squares square :- ))))

Very good Igor.

Derek

Igor Burger · « **Reply #27 on:** June 10, 2014, 02:16:56 PM »

:- )))) ... may be funny, but true ... I wrote it some time ago in SN

Tim Wescott · « **Reply #28 on:** June 10, 2014, 02:24:14 PM »

Quote from: Igor Burger on June 10, 2014, 01:34:55 PM

Derek: it helps to make rounds round and squares square :- ))))

If it's not obvious just looking at the mechanism, the flap moves more with respect to the elevator around neutral, and less as the elevator deflection gets high. This would give you more immediate response in altitude around neutral with less rotation, and visa-versa at high deflection. So for level flight and the rounds, it more or less shoves the airplane up and down without changing the direction of flight (much), while for high deflection it lets the elevator take over and actually rotate the airplane.

Nifty.

Derek Barry · « **Reply #29 on:** June 11, 2014, 05:55:39 AM »

Quote from: Igor Burger on June 10, 2014, 02:16:56 PM

:- )))) ... may be funny, but true ... I wrote it some time ago in SN

I know you did, I guess I should go back and read that article.

Derek

Trostle · « **Reply #30 on:** June 11, 2014, 08:23:19 AM »

Quote from: Tim Wescott on June 10, 2014, 02:24:14 PM

If it's not obvious just looking at the mechanism, the flap moves more with respect to the elevator around neutral, and less as the elevator deflection gets high. This would give you more immediate response in altitude around neutral with less rotation, and visa-versa at high deflection. So for level flight and the rounds, it more or less shoves the airplane up and down without changing the direction of flight (much), while for high deflection it lets the elevator take over and actually rotate the airplane.

Nifty.

Well, you do not need to be limited to be "just looking at the mechanism" photographs above. Check out Igor's website at

http://www.netax.sk/hexoft/stunt/the_max_ii.htm

This graphically shows the flap/elevator response.

Great website by the way.

Keith

Derek Barry · « **Reply #31 on:** June 11, 2014, 09:31:09 AM »

Quote from: Trostle on June 11, 2014, 08:23:19 AM

Well, you do not need to be limited to be "just looking at the mechanism" photographs above. Check out Igor's website at

http://www.netax.sk/hexoft/stunt/the_max_ii.htm

This graphically shows the flap/elevator response.

Great website by the way.

Keith

Thanks Keith,

I understand how it works now.

Igor, do you sell that setup and if so, how much?

Derek

MarcusCordeiro · « **Reply #32 on:** June 11, 2014, 02:47:42 PM »

Quote from: Derek Barry on June 11, 2014, 09:31:09 AM

Thanks Keith,

I understand how it works now.

Igor, do you sell that setup and if so, how much?

Derek

I was wondering the same here.....

Marcus

Igor Burger · « **Reply #33 on:** June 12, 2014, 03:41:33 AM »

Yes kits are regularly available for 25 Euro (as seen on picture)

If necessary, I can also arrange custom building of all parts (all horns, properly set slot to ball bearing, 4 hooks for pushrods with proper fit to bushings), it comes usually 120 euro. It is almost day of work, but I would not miss that fun of bulding it myself :- )))).

Lauri Malila · « **Reply #34 on:** June 12, 2014, 04:12:11 AM »

Igor,

About the lever dimensions;
With a quick look at your drawing, it seems that when flaps are in neutral position, the distaces from center of ball bearing to both pivot points is the same. Is it so?

Lauri

Igor Burger · « **Reply #35 on:** June 12, 2014, 04:17:34 AM »

no, it is 45:55