[NSRCA-discussion] More electric newbie questions

[Vicente "Vince" Bortone]

Something that I noticed with most electric pattern planes flying Masters. The down-line speeds in stall turns is very nice for most. However, the down-line speed on the square loop on corner last leg increases too much. For sure I would like to reduce that speed. In my case, using same settings and motor that Andrew is using. 

Thanks, 

Vicente "Vince" Bortone 

----- Original Message ----- 
From: "colin chariandy" <cchariandy at yahoo.ca> 
To: "General pattern discussion" <nsrca-discussion at lists.nsrca.org> 
Sent: Monday, June 20, 2011 2:58:43 PM 
Subject: Re: [NSRCA-discussion] More electric newbie questions 



I'm still trying to get my head around windmilling, low idle and higher idle being almost the same for downline speed. 

I would have thought (from traditional magnetics theory) that there should be some torque (synchronization) derived from the rotating field and the rotating magnets to resist speeding up. Unless the rotating feild is too weak at low RPM and once out of sync the speed increases with little resistance. Thus the question....is it better to have a higher idle (stronger field)? 

I am assuming that at low RPM both the PWM and the field voltage are lower than at higher RPM. 

The problem is that theory and actual test data often don't go hand in hand....and not many clock the speed of their planes. 




From: Dave Lockhart <DaveL322 at comcast.net> 
To: General pattern discussion <nsrca-discussion at lists.nsrca.org> 
Sent: Mon, June 20, 2011 3:25:11 PM 
Subject: Re: [NSRCA-discussion] More electric newbie questions 




Ooopsss…..I meant to respond to your 1), 2), and 4) scenarios…… 



I haven’t flown the 3) med brake setting on the Jeti…..but yes, it is possible to have too much brake, and then you will have a faster downline speed than just a windmilling prop. 


Dave 





From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of colin chariandy 
Sent: Monday, June 20, 2011 3:20 PM 
To: General pattern discussion 
Subject: Re: [NSRCA-discussion] More electric newbie questions 





Dave....so you are saying: 





No brake (regardless of idle or windmilling) - approx the same speed on downlines. 


Too much brake - faster than idle/no brake? 





Colin 







From: Dave Lockhart <DaveL322 at comcast.net> 
To: General pattern discussion <nsrca-discussion at lists.nsrca.org> 
Sent: Mon, June 20, 2011 1:00:02 PM 
Subject: Re: [NSRCA-discussion] More electric newbie questions 


Using Castle stuff…. 



1) and 2) definitely not…..the idle RPM is not governed, and will wind up substantially in downlines, RPM will be the same at the end of the downline whether starting at low idle or high idle. I’m not aware of any different behavior on other brands of ESCs. 

3) definitely not……wind up in downlines is virtually indistinguishable from using low idle. 



Depending on just how many braking parameters you can adjust (which does vary between Castle, Jeti, Schulze, YGE), it is possible to have too much brake…..at a point, the downlines will become faster again when the prop disc is spinning too slowly. I’ve been told that the ideal idle RPM (for maximum braking) can be calculated, but I don’t know anyone that has done this (and I certainly don’t have the knowledge to run the numbers). 



Regards, 



Dave 





From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of colin chariandy 
Sent: Monday, June 20, 2011 11:44 AM 
To: NSRCA Mailing List 
Subject: [NSRCA-discussion] More electric newbie questions 





I can't find any definative reading on this so I have to ask the group. 





Which configuration provides the most braking on downlines and approach for landing (Jeti 90 + evo 30-10) : 





1) Lowest possible idle 


2) Windmilling prop 


3) Jeti Med brake 


4) Slighlty higher idle 





My testing has not been conclusive....just not enough data. 





Thanks 


Colin. 
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