RunRyder RC
 1  Topic Subscribe
WATCH
 1 page 677 views
HelicopterRadio - Servo - Gyro - Gov - Batt › Equal cyclic throws; 100% vs 140% ATV
06-01-2004 01:12 PM  13 years agoPost 1
Taipan

rrElite Veteran

Sydney, Australia

My Posts: All  Forum  Topic

Just read Jason & Todd's latest tips here; http://www.littlerotors.com/article...290504/day2.asp

They said to use maximum ATV wherever possible. This got me thinking. Assuming equal throws for both setups, the balls on the servo horns would have to be moved in & out depending on how much ATV is used.

To be continued...

PM  EMAIL  GALLERY  Attn:RR  Quote
06-01-2004 01:16 PM  13 years agoPost 2
Drunk Monk

rrProfessor

Preston, UK

My Posts: All  Forum  Topic

Using more ATV's would make travel slower but give higher resolution. Why would you want to use 140% atv if you can get 100%


Stephen

I only open my mouth to change feet.....

PM  EMAIL  GALLERY  Attn:RR  Quote
06-01-2004 01:50 PM  13 years agoPost 3
z11355

rrMaster

New England

My Posts: All  Forum  Topic

servo systems use 1024 'steps' or unique
digital words in order to position the servo.

Those 1024 have to cover the ENTIRE specified
range of movement.

Now, the servo movement is not linear but an
approximation. As the window of movement
gets wider, the approximation gets worse,
particularly at the end points. Thats because
the servo movement actually looks like the
almost-flat portion of a sine curve and the
flat-ness gets worse at the extremes.

Lets assume the maximum range is +- 45 degrees
at 140% ATV, and +-30 degrees @ 100% ATV.

So if you are using only 100% ATV, you're in
fact throwing away about 40% of your resolution
1024/200 instead of 1024/280 although the
angular resolution is always the same.

PM  EMAIL  GALLERY  Attn:RR  Quote
06-01-2004 02:04 PM  13 years agoPost 4
Secret Squirrel

rrKey Veteran

New Zealander living in Melbourne, Australia

My Posts: All  Forum  Topic

Gidday Kevin,
Sorry I should have been a bit clearer in that article. I think what they meant is to maintain the highest ATV's that your linkages will allow. FWIW, my ATV's are 100% which they gave the thumbs up to.

BTW, I digitised the video of Jason beating on my CS today. Makes for good watching. Once I've got it done, I'll post if for you guys to see.

Si

PM  EMAIL  HOMEPAGE  Attn:RR  Quote
06-01-2004 02:12 PM  13 years agoPost 5
Drunk Monk

rrProfessor

Preston, UK

My Posts: All  Forum  Topic

throwing away about 40% of your resolution
Ok, I can accept that, so for 100% and +/-30 degrees for instance you might have a 60 degree time of .1 for example. But to use the full movement of 90 degrees (from your example) you would end up with an extra 30 degrees of travel which would mean that full travel from 1 extreme to other would be 1.5 seconds. Would it not then be better to stick to the 100% atv +/-30 degrees and have the nice fast .1 while still maintaining the same resolutions?


Stephen

I only open my mouth to change feet.....

PM  EMAIL  GALLERY  Attn:RR  Quote
06-01-2004 02:38 PM  13 years agoPost 6
z11355

rrMaster

New England

My Posts: All  Forum  Topic

maintaining the same resolutions?
but that requires changing the length of the
servo arm due to the rotary-linear translation.

It's all a fine balancing act between speed,
servo arm, ATV, etc etc

would I use 140? no
would I use 110-125 or so? probably

PM  EMAIL  GALLERY  Attn:RR  Quote
06-02-2004 12:09 AM  13 years agoPost 7
Taipan

rrElite Veteran

Sydney, Australia

My Posts: All  Forum  Topic

Here's my burning question...

Which is faster, stronger, more precise or best combo? 100% & balls far apart or 140% & balls closer in??

Thought 140% is faster, guess not, just more throw. Might've just answered my own question!

PM  EMAIL  GALLERY  Attn:RR  Quote
06-02-2004 12:36 AM  13 years agoPost 8
PietervA

rrVeteran

New Zealand

My Posts: All  Forum  Topic

Using the JR 3810/8103 without governor, you have to set the throttle ATVs at +/-150% if you're using cyclic to throttle mix and run max pitch curves, otherwise the throttle servo binds with max pitch and some cyclic input. A bit irritating.

The 9X does the same, but believe the 10X has dedicated mixes which address this problem. Multiplex get around this issue by calibrating the servos for endpoints and centre point. Have no experience of Futaba heli radios.

The TJ Pro with throttle ATV of approx +/-100% does away with this irritation, of course, as throttle servo travel range is calibrated into the governor.

Ciao

PM  EMAIL  GALLERY  Attn:RR  Quote
06-02-2004 02:14 AM  13 years agoPost 9
z11355

rrMaster

New England

My Posts: All  Forum  Topic

pva, your method is overly complicated.

all you really have to do is add enough subtrim
so the servo stops responding and then reset
the servo arm to be at 'throttle max'. Now, no
matter what any mix or anything else says, the
servo canNOT move any farther than this.

PM  EMAIL  GALLERY  Attn:RR  Quote
06-02-2004 02:46 AM  13 years agoPost 10
PietervA

rrVeteran

New Zealand

My Posts: All  Forum  Topic

If I understand what you're saying, this would work at the one end of the scale (eg full throttle, in ST2), but you'd run into difficulty at the lower end (closed throttle, in NOR).

I want to have my cake and eat it!

If there is a different way of using sub-trims, this would be really useful. Russ Deakin describes the use of subtrims to get 3 headspeads on his TJ Pro (for example), using only one mixer. I don't understand the theory, and so haven't applied this in practice!

Regards

PM  EMAIL  GALLERY  Attn:RR  Quote
06-02-2004 02:57 AM  13 years agoPost 11
z11355

rrMaster

New England

My Posts: All  Forum  Topic

thats true but my answer to that is 'who cares'
about the low side of normal mode. I only use
that when I'm spooling up or spooling down.

any flight is conducted @ 3/4 and above in
normal mode and even w/o GV1, you're well
above the 50% mark in idle-ups

PM  EMAIL  GALLERY  Attn:RR  Quote
06-02-2004 07:15 AM  13 years agoPost 12
PietervA

rrVeteran

New Zealand

My Posts: All  Forum  Topic

Point taken.
Thanks.
Ciao

PM  EMAIL  GALLERY  Attn:RR  Quote
WATCH
 1 page 677 views
HelicopterRadio - Servo - Gyro - Gov - Batt › Equal cyclic throws; 100% vs 140% ATV
 Print TOPIC  Make Suggestion 

 1  Topic Subscribe

Wednesday, December 13 - 11:23 am - Copyright © 2000-2017 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online