[NSRCA-discussion] SD-10

Atwood, Mark atwoodm at paragon-inc.com
Tue Aug 25 06:41:36 AKDT 2009 

I actually think we're both right and that the specs are starting to exceed our needs which is awesome.  As for brand wars, no, I didn't think it was either...I just didn't want it to become one.

Appreciate all the conversation!

-Mark
(PS, and it may even be an E-Passport)

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Anthony Frackowiak
Sent: Tuesday, August 25, 2009 10:36 AM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] SD-10

Hi Mark,

I never saw this as a "brand" war, I was just trying to correct what I  
saw as some misconceptions out there and perhaps express another  
viewpoint. I guess this really comes down to an agreement to disagree.  
You feel resolution greater then 1024 is below recognition and I feel  
latency below 40 ms is below that point. The great thing about the  
hobby is that the buyer has a lot of choices. So I guess you pick your  
poison!

And you are correct about electric being better!

Thanks!

Tony


On Aug 25, 2009, at 6:59 AM, Atwood, Mark wrote:

> Hey Tony,
>
> I don't disagree with your math or understanding, though I'm trying  
> to make a slightly different point I think. I also misspoke in a  
> previous post regarding how the resolution and EPA settings  
> interact, you're explanation is clearer and is also my understanding.
>
> I also want to state that I'm not advocating that 2048 isn't  
> "better".  The original question was "Why didn't ATX choose 2048  
> over 1024" and the answer from their end was cost and the "opinion"  
> that given the cost choice between speed and resolution, that speed  
> had a more noticeable impact on most setups.
>
> The point I want to express is analogous to making your house more  
> secure by putting 4 giant deadbolt locks...on a hollow core door.   
> You're only as safe as your weakest point of entry. Be it kicking  
> through the door or breaking a window...the locks are more than  
> adequate and no longer the weak point in the system.  I believe the  
> same is true for resolution, it's no longer the weak point in the  
> system.
>
> To follow your math/understanding, the "step" size for a given  
> resolution is constant.  So in your max travel example, which I  
> think is a good one, we're probably talking about spreading  
> 1024/2048 across 135 degrees of throw at max.  Thus the "step" size  
> for 2048 is approx 1/15 of a degree, and therefore at 1024 it's  
> approx 1/7th of a degree.  Regardless of how you dial down your  
> rates, that will always be the smallest step size.  I.e. if you  
> reduce rates as you suggested, reducing EPA to 100% from 150% (down  
> to 90degrees) and D/R down to 80% from 100% (down to 72degrees of  
> rotation) we now have 1080 pts across 72degrees with 2048, or 540  
> pts across 72degrees with 1024.  In Both cases the step size is  
> still 1/15 of a degree or 1/7th respectively.
>
> My assertion is simply that 1/7th of a degree of resolution (approx . 
> 0012" movement on a 1" servo wheel) is smaller than other area's of  
> inaccuracy in our setups.  Or at least in most people's setups.   
> Getting a setup tighter than that is hard.  Keeping it there is even  
> harder. Servo gear trains have slop, ball links, clevises (big  
> slop), wing adjusters, even the wing tube all allow for movement in  
> micro amounts that ruin our accuracy at a given point. And I won't  
> even mention the variance in deflection if you're flying glow due to  
> vibration which I'm sure makes this whole conversation moot.  (I  
> know I know...I need to convert to Electric...you keep telling me!  
> I'm working on it!).
>
> Anyhow, I hope you understand my perspective. People are choosing  
> where best to spend their money to gain the most functionality and  
> advantage in their flying setups, and in a similar fashion  
> Airtronics did the same.  They felt they were giving the pilot the  
> best bang for the buck by choosing speed over resolution.  I DO  
> think when they complete their flagship radio (a ways out) it will  
> likely be 2048 so as to be comparable with the other top of the line  
> systems.  I'm also pretty sure it won't be $500 though.
>
> This has been a great discussion though and hopefully enlightening  
> to some.  I did not mean for it to be a brand war on features though  
> as clearly I have bias as an Airtronics pilot.  I just wanted to try  
> and answer the question.  I'm happy to discuss further off list, or  
> answer other specific questions on or off list, but for now I'm  
> going to bow out of this thread.
>
> Thanks,
>
> Mark
>
> -----Original Message-----
> From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org 
> ] On Behalf Of Anthony Frackowiak
> Sent: Tuesday, August 25, 2009 12:55 AM
> To: General pattern discussion
> Subject: Re: [NSRCA-discussion] SD-10
>
> I'll try to explain this as I understand it. With a 2048 system you
> get 2048 TX step outputs through the entire stick travel only if the
> electronic throws in the TX are set to Max. Say that's 150% Travel at
> 100% Dual Rate. Those numbers vary amongst the brands and models but
> this is a start. Any reduction from there will reduce the 2048 by some
> percentage. Let's say Travel is set to 100% and Dual Rate remains
> 100%. You have just reduced the number of steps by 33% so now you're
> down to around 1350. If you reduce the Dual Rate to 80% from there
> you're now flying on 1080. If this started out as a 1024 you would end
> up at 540. I guarantee you'll feel the difference between 1080 and  
> 540.
>
> I always try to maximize the electronic throws and set the mechanicals
> to get the surface travel I desire. But some things are inevitable. To
> get the model to properly break in a spin takes a lot of elevator
> deflection, so I end up flying with DR set to 50% or so for normal
> flying. The higher 2048 system makes a difference with this sort of an
> example. And I do believe the better servos will respond to this fine
> of a command.
>
> Hope this isn't too confusing.
>
> TonyF
>
>
>
> On Aug 24, 2009, at 8:14 PM, Atwood, Mark wrote:
>
>> The resolution is for the full throw of the servo. If you bump your
>> endpoints up to 150% and have 135deg of travel, you have 512 / 1024
>> or 2048 individual points in between.  At a normal 100% that's
>> across 90degs of throw.  If you dial your endpoints down, it's
>> spread across a smaller arc.
>>
>> We're talking about extremely fine movement even at 512 resolution.
>>
>> What's nice is that all the components of the Accuracy "system" are
>> improving together.  The pots in the new radios (all brands) are
>> significantly more accurate, the digital servos of all brands are
>> significantly more accurate, and our linkage systems continue to
>> improve as well.  My argument was simply that after 1024 (and
>> probably lower actually), the resolution is probably not the "weak
>> link" in the accuracy chain.  We have too much slop elsewhere.  Even
>> a tight servo has some lash, as do the connections to the servo and
>> even movement of the control surface on the hingeline.
>>
>> Admittedly though, On a LARGE control surface like a 40% IMAC
>> Rudder, you can still see the surface "Step" if you move it slowly
>> and watch carefully even with 1024.  So to say that 2048 is not
>> smoother would be foolish.  But on our pattern planes and the throws
>> we use, the other sources of error take resolution off the critical
>> path to more accuracy.
>>
>> So to slightly change the topic, how do we get spec's on the
>> resolution/accuracy of the servos?  Does anyone publish that? (I'm
>> pretty sure Atx doesn't).  That would be as important than just
>> about any other spec I would think.
>>
>> -----Original Message-----
>> From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org
>> ] On Behalf Of Lisa n Larry
>> Sent: Monday, August 24, 2009 10:31 PM
>> To: 'General pattern discussion'
>> Subject: Re: [NSRCA-discussion] SD-10
>>
>> I'm curious...
>>
>> How many degree of servo throw for 1024/2048 are we talking?
>>
>> -----Original Message-----
>> From: nsrca-discussion-bounces at lists.nsrca.org
>> [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of
>> Ronald Van
>> Putte
>> Sent: Monday, August 24, 2009 8:34 PM
>> To: General pattern discussion
>> Subject: Re: [NSRCA-discussion] SD-10
>>
>> Geez!  I was happy with 512.
>>
>> Ron VP
>>
>> On Aug 24, 2009, at 3:13 PM, mike mueller wrote:
>>
>>> So a 2048 is smoother than a 1024 by double. I wonder at what
>>> point you no longet "feel the difference".?
>>> For me it could be as soon as tomorrow. M2
>>>
>>> --- On Mon, 8/24/09, Jay Marshall <lightfoot at sc.rr.com> wrote:
>>>
>>>> From: Jay Marshall <lightfoot at sc.rr.com>
>>>> Subject: Re: [NSRCA-discussion] SD-10
>>>> To: "'General pattern discussion'" <nsrca-
>>>> discussion at lists.nsrca.org>
>>>> Date: Monday, August 24, 2009, 3:05 PM
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Frank, you
>>>> are getting your terms mixed
>>>> up. The 1024 & 2048 refer to the number of
>>>> "steps" from one end
>>>> of the stick movement to the other. The speed, known as
>>>> latency, is the time it
>>>> takes from the instant you change the stick to the time the
>>>> servo moves. Actually,
>>>> it is the time until the servo receives the command to
>>>> move. The two functions
>>>> are not dependant upon each other.
>>>>
>>>>
>>>>
>>>> As far as
>>>> keeping up, that depends on
>>>> servo speed. It is possible to have a switch change which
>>>> instantly commands a
>>>> function from low to high, for example. The time to get
>>>> there, however, will
>>>> depend on how fast the servo can move.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Jay Marshall
>>>>
>>>>
>>>>
>>>> -----Original
>>>> Message-----
>>>>
>>>> From:
>>>> nsrca-discussion-bounces at lists.nsrca.org
>>>> [mailto:nsrca-discussion-bounces at lists.nsrca.org]
>>>> On Behalf Of
>>>> frank
>>>>
>>>> Sent: Monday,
>>>> August 24,
>>>> 2009
>>>> 3:30
>>>> PM
>>>>
>>>> To:
>>>> 'General pattern
>>>> discussion'
>>>>
>>>> Subject:
>>>> [NSRCA-discussion] SD-10
>>>>
>>>>
>>>>
>>>> Hi Anthony,
>>>> Jim, Mark , and Others
>>>> who Responded,
>>>>
>>>>
>>>>
>>>> Thanks for
>>>> your valuable input.
>>>> I've read that this radio's resolution is or is
>>>> among the very
>>>> fastest; so much so that even digital servos
>>>> can't keep up with it.
>>>> I understand  that the system is 1024 , but
>>>> can't help but
>>>> wonder why it isn't 2048. I'm sure
>>>> I'll get past my
>>>> hangup, but would appreciate everyone's
>>>> insight's on that
>>>> one.
>>>>
>>>>
>>>>
>>>> Thanks,
>>>>
>>>> Frank
>>>> Imbriaco
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> -----Inline Attachment Follows-----
>>>>
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>>>
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