RunRyder RC
 8  Topic Subscribe
WATCH
 3 pages [ <<    <    ( 1 )     2      3     NEXT    >> ] 8178 views
HelicopterRadio - Servo - Gyro - Gov - Batt › Cyclic Stick Limiter Rings
11-29-2005 07:54 AM  12 years agoPost 1
GimbalFan (RIP)

rrProfessor

Big Coppitt Key, FL

My Posts: All  Forum  Topic

Here's a useful idea about transmitters & RC helis that's actually been around for quite awhile. For those who're new to RC helicopters, it's a concept worth considering. For heli pilots who fly with Mode 1 or Mode 4 tx's -- unfortunately this tool won't be of any use to you because only Mode 2 and Mode 3 tx's have their elevator and aileron (cyclic) controls on one stick.

. . . . .
A Ring on a Mode 3 (lefty) TX . . . . . . . . . . Stick Modes . . . . . . .

After seeing a couple of them at the field, I made a cyclic stick limiter ring such that the stick throws on my 7CHP are still 100% at the 3, 6, 9 & 12 o'clock positions, but limited at the corners. I was then able to adjust my tx's servo end points on both elevator and aileron up about 22% before I began dragging the shoulder of the swashplate against the mainshaft on my R50.

As it turns out, the large servo wheel that comes with Futaba servos (9252's and others, part# FUTM2035) is exactly the right outer diameter for the 'seat' at the base of the gimbal of a 7CHP, for some other Futaba tx's and even for some non-Futaba tx's -- thanks to ChuckHager for that discovery. The servo wheel even has a slight bevel on the outer edge making it easy to press securely into place for flying helis and pop quickly back out for flying planks.

After measuring the stick throws, I used a drill press to drill a 7/8" (22mm) hole in the wheel's center. I used a 13/16" (21mm) cylindrical sanding drum to smooth out the cut and bring it out to just the right inner diameter for the stick throws on a Futaba 7CHP, about 29/32" (23mm). I also beveled this inside hole about 40 degrees so the tx stick would have a flat seat to rub against.

In the 1st and 2nd pics above you can see the concentric guide ridges on the 'bottom' and the beveling on the outside edge that are part of the original servo wheel mold. The concentric ridges are useful for keeping the inner hole round & centered as you enlarge it to fit your stick throws. The outer diameter of the servo wheel will fit a few other models and brands of tx's as well.

Some prefabbed limiter rings attach instead to the cyclic stick itself between the locking parts of the stick height adjustment. Either one accomplishes the same thing, but this method allows for quicker removal for plank flying.

When using one of these rings, GREAT care must be taken in the tx setup to confirm ZERO binding of the swash frame shoulder on the mainshaft, AND on ALL the linkages and ball link ends on the entire rotorhead, at ALL cyclic and collective stick positions.

I have 22% more swash angle available now at the 3, 6, 9 & 12 o'clock stick positions than I did when the tx stick's 'corners' were my limiting dimension for setting the aileron & elevator endpoints on my tx. Although this seems to be okay on a Raptor 50, it may be too much swash angle for other helis.

I recommend backing off at least 5-10% on your tx's elevator & aileron servo endpoints from the start of swashplate binding until you're absolutely SURE your bird will be happy with the greater angles.
_____

We have the good fortune here in Vegas of flying alongside all 3 Szabo Boys, and both Alans (Sr & Jr) along with Jeff Fassbinder of Thunder Tiger were all at Bennett Field the day I tested this new setup.

Alan Jr was sure that the 22% greater swash angles wouldn't over-stress the linkages on an R50's head when using the ring. Nonetheless, for the first test
I backed off about 10% on the elevator & aileron endpoints (2 degrees of swash angle). Nice.

Then I swapped out the 30g black paddles for 20g greens. Nice!

Then I bumped the endpoints back up to just shy of binding. NICE!!
_____

This ring has worked out real well for maximizing swash deflection. They're a great idea for anyone who's concerned about binding while 'in the corners'. Thanks to ChuckHager for the original idea and the servo wheel suggestion, to Eric_B for his accurate numbers on swash angle and to Alan Jr for his linkage assessment (and for lots of other answers over the past 6 months).

Did I mention that Alan Jr and Danny both use stick limiting rings?

They do, but whereas this is a hardware ring, theirs run as software - between their flippin' ears - because they're that flippin' good. As for me, I'll use a ring.

(Yes, that tx is a lefty -- don't ask.)

EDIT: I first made a ring for that (above) Futaba 7C (in stick Mode 3).

I've since graduated to an Airtronics Stylus, whose gimbal pots can be user- recalibrated. As a thumber I prefer shorter maximum stick throws A smaller ring reduced stick travel by 15%, which also reduced stick (and therefore servo) resolution (the number of individual discrete servo arm positions over the arc of its travel). Recalibrated, they again have full 1024-step resolution.

Not essential, but a worthwhile addition if a tx's sticks can be recalibrated.

op-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-t

PM  EMAIL  GALLERY  Attn:RR  Quote
11-29-2005 12:11 PM  12 years agoPost 2
colsy

rrElite Veteran

Cambridge, UK

My Posts: All  Forum  Topic

Gimbalfan, that is a most excellent post, and very well written.
as i always thought these devices fitted to the stick itself and not the gimbal face.
Now i understand, but anychance of a slightly better picture,
Makes you wonder why The TX manufacturers dont offer these as an option..
Thanx Again Colin..............................

Only Quote From Experience.

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
11-29-2005 02:07 PM  12 years agoPost 3
crowfly

rrVeteran

Pleasant View, TN U.S.A.

My Posts: All  Forum  Topic

COLSY

Here's a view of just the ring. Notice that the inner circle is beveled to match the slant angle of the stick.

http://www.ronlund.com/Merchant2/me...t_Code=FMPRINGJ

If God had meant for man to fly, he would have given him more money

PM  EMAIL  Attn:RR  Quote
11-29-2005 04:19 PM  12 years agoPost 4
colsy

rrElite Veteran

Cambridge, UK

My Posts: All  Forum  Topic

Thanx again, it all makes sense now, i shall get one of my lads to knock me one up at work, i just need to work out the bevel angle to suit JR 9X11,
How are you boys holding it in place, without drilling into gimbal's, only just got my 9x so dont want warranty validation.
Cheers Col..............

Only Quote From Experience.

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
11-29-2005 04:38 PM  12 years agoPost 5
crowfly

rrVeteran

Pleasant View, TN U.S.A.

My Posts: All  Forum  Topic

The "store bought" ones come with double sided tape & a great set of instructions.

If God had meant for man to fly, he would have given him more money

PM  EMAIL  Attn:RR  Quote
11-29-2005 08:14 PM  12 years agoPost 6
GimbalFan (RIP)

rrProfessor

Big Coppitt Key, FL

My Posts: All  Forum  Topic

anychance of a slightly better picture,
Colin, you can click on any thumbnail on RR and get a larger image. Sometimes clicking again gets one even larger.

On my Futaba 7CHP the ring size just happens to be a perfect press fit into the 'seat' of the gimbal face, almost as if they designed it that way. If you also fly planks with that tx, dbl-sided tape might be a problem.

Glad you found it useful. I'm surprised I don't see more of them.

You'd be amazed at how many rookies AND veterans have swash/shaft binding issues that at the least are scuffing their mainshafts, and at the worst are wearing out their cyclic servos and actually notching their mainshafts.

op-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-t

PM  EMAIL  GALLERY  Attn:RR  Quote
11-29-2005 08:27 PM  12 years agoPost 7
crowfly

rrVeteran

Pleasant View, TN U.S.A.

My Posts: All  Forum  Topic

You might be surprised to find out how many people never stick it in the corners.

If God had meant for man to fly, he would have given him more money

PM  EMAIL  Attn:RR  Quote
11-30-2005 08:50 AM  12 years agoPost 8
Pelos

rrVeteran

Bizkaia (Spain)

My Posts: All  Forum  Topic

There's a very good post about rings here that shows one (little) problem: The throws on elevator and aileron aren't equal, at least in futaba transmitters (the stick makes more travel in aileron direction than in elevator). The hole ideally should be eliptical.
Nevertheless, I made mine some time ago the way you posted, and works well. Mi Tx is a 9CHP and the ring fits a litle loose, but it works.

Is there a life outside the sim?

PM  EMAIL  GALLERY  Attn:RR  Quote
11-30-2005 10:28 AM  12 years agoPost 9
Al Magaloff

rrMaster

12,199 Posts- Enough Time Wasted. See Ya!

My Posts: All  Forum  Topic

The throws on elevator and aileron aren't equal
Something wrong with this! You're saying the transmitter has different output ratios between the two?

PM  EMAIL  Attn:RR  Quote
11-30-2005 11:04 AM  12 years agoPost 10
Pelos

rrVeteran

Bizkaia (Spain)

My Posts: All  Forum  Topic

The phisical travel of the stick is different, at least in 9C and 9Z wich I both own. If you attach a true circular ring sized to aileron full travel, the stick does not touch the ring in full elevator. If you size the ring to elevator, you never reach full aileron travel. There is maybe 1,5 or 2 mm more travel for aileron than elevator.

Is there a life outside the sim?

PM  EMAIL  GALLERY  Attn:RR  Quote
11-30-2005 11:11 AM  12 years agoPost 11
Al Magaloff

rrMaster

12,199 Posts- Enough Time Wasted. See Ya!

My Posts: All  Forum  Topic

Strange that Futaba would go that way. Has there ever been an explanation of why ?

PM  EMAIL  Attn:RR  Quote
11-30-2005 07:33 PM  12 years agoPost 12
GimbalFan (RIP)

rrProfessor

Big Coppitt Key, FL

My Posts: All  Forum  Topic

That difference in stick throws must be model specific. That's certainly important to know. After reading your post, Pelos, I remeasured my 7CHP again and found them to be equal.

Thanks for pointing that out.

op-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-t

PM  EMAIL  GALLERY  Attn:RR  Quote
12-01-2005 12:59 AM  12 years agoPost 13
Pelos

rrVeteran

Bizkaia (Spain)

My Posts: All  Forum  Topic

I don't know the reason, and yes, I made mine round and live with that.

Is there a life outside the sim?

PM  EMAIL  GALLERY  Attn:RR  Quote
03-03-2009 03:52 PM  8 years agoPost 14
Dood

rrProfessor

Wescanson

My Posts: All  Forum  Topic

There are 2 basic designs of cyclic rings.
One is a true circle (left), the other type of ring is a squarish circle (right).

I much prefer the squarish-type cyclic ring as it limits stick travel ONLY in the corners where it needs it to prevent binding.

I feel that the round cyclic ring is inferior as it may limit stick travel 360º.

To compensate for the stick travel-limiting ring, cyclic rates would need to be increased to match the capabilities as if you had no ring at all, therefore robbing the stick of it's native resolution.

Even worse are the homemade rings with an even smaller opening that are often used as a training aid for learning piro & "chaos" maneuvers.

  ▲
▲ ▲

PM  EMAIL  GALLERY  Attn:RR  Quote
03-03-2009 03:58 PM  8 years agoPost 15
GimbalFan (RIP)

rrProfessor

Big Coppitt Key, FL

My Posts: All  Forum  Topic

The squarish ring concept makes no sense.

If cyclic stick travel limits are circular, then achieving equal swash deflection in all directions without binding the swash shoulder on the mainshaft is easy.

But a squarish ring oriented with its rounded 'corners' at the 3, 6, 9 & 12 o'clock positions will either result in less than full swash deflection in the corners, or too much deflection while at the 3, 6, 9 & 12 o'clock positions.

The fundamental purpose of a limiter ring to achieve maximum and equal swash deflection in all directions without binding.

op-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-t

PM  EMAIL  GALLERY  Attn:RR  Quote
03-03-2009 04:02 PM  8 years agoPost 16
Dood

rrProfessor

Wescanson

My Posts: All  Forum  Topic

If stick travel is circular
I disagree that travel is circular, at least on my JR radio.
Pushing a gimbal stick to it's limit, it is clear that it's travel limit follows a square pattern.

  ▲
▲ ▲

PM  EMAIL  GALLERY  Attn:RR  Quote
03-03-2009 04:06 PM  8 years agoPost 17
GimbalFan (RIP)

rrProfessor

Big Coppitt Key, FL

My Posts: All  Forum  Topic

I disagree that travel is circular, at least on my JR radio.
Pushing a gimbal stick to it's limit, it is clear that it's travel limit follows a square pattern.
The square pattern inherent in all tx's is what we aim to correct (for helis) with a ring in the first place.

Of course, some helis' head designs end up such that they can handle more deflection fore & aft than left & right (or vice versa) -- and some tx's have less stick throw fore & aft than left & right (or vice versa).

In my mind a limiter ring's hole should be made either circular or somewhat elliptical to take full advantage of its purpose. Since it's a heluva lot easier to make a circular hole than an elliptical one, and since any inequities can easily be programmed out with the tx's endpoints, circular makes the most sense.

op-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-thwop-t

PM  EMAIL  GALLERY  Attn:RR  Quote
03-03-2009 04:16 PM  8 years agoPost 18
Dood

rrProfessor

Wescanson

My Posts: All  Forum  Topic

Isn't the fundamental purpose of a limiter ring to achieve maximum and equal swash deflection without binding?
Negative on the Equal swash deflection.
For example, the helicopter may require more fore/aft swash deflection to make the flip rate match it's roll rate.

While I agree that it makes sense for stick travel to be symmetrical, swash travel should not be.

When you get to the point where you are physically limiting stick travel where it should be at it's highest and must compensate for this by increasing rates electronically (either with D/R, travel limit or swash mix) thats when I feel you'd be robbing the radio of it's native resolution.

  ▲
▲ ▲

PM  EMAIL  GALLERY  Attn:RR  Quote
03-03-2009 04:16 PM  8 years agoPost 19
helical

rrApprentice

Bowling Green, KY

My Posts: All  Forum  Topic

True enough, but that square pattern inherent in all tx's is what we're aiming to overcome with a ring (for helis) in the first place.

Of course, some helis' head designs end up such that they can handle more deflection fore & aft than left & right (or vice versa) -- and some tx's have less stick throw fore & aft than left & right (or vice versa), so in my mind a limiter ring should either be circular or somewhat eliptical to take full advantage of its purpose.
I agree.

And as per the second paragraph, I made a homemade ring for my old 9C and learned that it needed to be slightly eliptical in the aileron direction to get full travel.

I'm not understanding Dood's assessment of the square ring. It seems like it would limit travel in the corners of throw.

PM  EMAIL  GALLERY  Attn:RR  Quote
03-03-2009 04:19 PM  8 years agoPost 20
Dood

rrProfessor

Wescanson

My Posts: All  Forum  Topic

I'm not understanding Dood's assessment of the square ring. It seems like it would limit travel in the corners of throw.
As it does. It limits travel in the corners, and in the corners only.

  ▲
▲ ▲

PM  EMAIL  GALLERY  Attn:RR  Quote
WATCH
 3 pages [ <<    <    ( 1 )     2      3     NEXT    >> ] 8178 views
HelicopterRadio - Servo - Gyro - Gov - Batt › Cyclic Stick Limiter Rings
 Print TOPIC  Make Suggestion 

 8  Topic Subscribe

Wednesday, December 13 - 7:33 am - Copyright © 2000-2017 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online