[NSRCA-discussion] Max volts - fresh comparison?

Thu Mar 4 05:16:03 AKST 2010

I agree with most of what you say, except for #3. I personally don't feel weather messes with the electrics nearly as much as with glow. Changing density altitude will affect the propellor performance of both. However, temp, humidity, altitude will also affect the performance, and especially the settings, of an IC engine. If you take both an electric and an IC plane to 10k feet altitude, you could change the prop on the electric (larger, more pitch) and get back all the power - you don't inherently lose power with the electrics due to altitude, in fact you can still get all the power from an electric motor in a complete vacuum as long as you can present it with a load. The IC engine at 10k feet, you will have to mess with fuel (more nitro), mixture settings, as well as prop, and you will probably never get back all the power.  Now, cooling could be an issue with the electrics since the air is less dense at higher altitude.

Ponder this: when was the last time you saw someone fly an .049 powered plane?  I have not seen one in years. In fact, most of the .25 sized or smaller planes are almost all electric now. I have to ask why?

I have lots of electrics, a few glow powered, and a few gassers. So, I am speaking as someone that does them all. They all have their advantages, allure, nostalgia or whatever. Don S let me fly his 1.70 powered Black Magic at Bealton last year, and I was VERY impressed.  However, if I ever put together another competition pattern plane, I am going to lean heavily towards electric. Not due to performance or weight or cost, but because I have been happy with the smaller electrics thus far, and I don't miss having to clean up the plane after each flight.

Either you like electrics, or you don't - to each their own. Can't we all just get along? :-)

Bob R.

--- On Thu, 3/4/10, Woodward, Jim R (US SSA) <jim.woodward at baesystems.com> wrote:

Bingo – “Dave quote, The “biggest lie” about electrics is that they always produce the same amount of power.  Phooey.  Ambient temperature has a big influence.”

Truths about electric – from a glow flyer’s perspective: 
1.       The holy grail of absolute consistency – is false 
2.       The holy grail of motor system security – is false  - must still carry extra motor, ESC, Battery 
3.       Weather effects are at least equal compared to glow – temps, humidity, wind, effect mah usage 
4.       11 lbs weight limit is significantly more difficult to meet with electric plane than glow 
5.       E-deadsticks or low-power runs still occur 
6.       Must have field charging solution – most likely Honda generator 
7.       Must have temp-control measures in place for batteries (hot dashboard or warm blanket?) 
8.       Can have an “E-crash” while flying – ESC or battery starts smoking/fire 
9.       Battery safety ??? 
10.   Reduced flight time - All this ruminating and crazyness for 8-9 minutes of flight time?? 

>From my perspective, the only reason to fly electric would be if the industry and judging trends were so badly biased towards electric, that it became the only “competitive” solution available.  I’m leaving the “sponsorship” component out of the equation, because people on the E or G side of the discussion have sponsorships either way.  It just seems like a large pain in the arse to fly electric, given the reduced flight times and severe penalty on battery life if you fly too long.  

Given all this, what is the E-flyer really getting? 

Thanks, 
Jim W. 

From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of rcmaster199 at aol.com
Sent: Wednesday, March 03, 2010 11:48 PM
To: nsrca-discussion at lists.nsrca.org
Subject: Re: [NSRCA-discussion] Max volts

Ed,

I'm not so sure. Most IC's don't have a pressure regulator...the YS is about the only one. This a passive device that has fixed settings. Dave's example of the EFI may be a dfferent story though...I never spent any time dealing with the OS EFI so I don't know how it worked. 

The problem with such analogies is that gas and glow fuels have a fixed amount of pop per unit mass. Put in X amount and you will pretty much get Y out for any given set-up, even poor ones. Y would vary of course depending on how good the set-up was, meaning different operators will probably get different Y's. However Y would be pretty much fixed for each operator

Batteries on the other hand, have a continuously variable amount of pop per unit mass. Electronically taking the variable input volts and, through some apparently straight forward software, drive a constant Y at the motor, is where I am having some issue with. 

As for ESC's not doing much to alter the piloting of the model, again I am not so sure. Dean used a good example: at near the end of the flight, let's assume there is a diagonal or vertical. The battery has lost some pop and the motor won't be able to keep up under constant throttle conditions. The pilot would need to make a throttle adjustment to maintain momentum. If the ESC had this new programming, the pilot would fly through this without hardly noticing or changing his flying, just like we do with ICs. I certainly am NOT opposed to reducing pilot work load...it's the how not the what. 

And in this particular instance, equality between the types of propulsion IS what the programmable ESC proponents want.....

The rule as written is sticky. I think that some type of clarification or addendum to the rule, as Earl suggested, would eliminate the sticky wicket if you will.

BTW- I am not implying that Dean is against the programmable ESC, far from it. He has thought through what would be needed to accomplish the task. In fact, he did something similar to Bob Hunt's WC stunt entry a few years ago. 

Matt

-----Original Message-----
From: Ed Alt <ed_alt at hotmail.com>
To: NSRCA List <nsrca-discussion at lists.nsrca.org>
Sent: Wed, Mar 3, 2010 7:56 pm
Subject: Re: [NSRCA-discussion] Max volts

I actually was only halfway joking I said "Ban the YS Pressure Regulator", or something like that.  Not that I really think it should be banned, but for everyone who thinks it would be cheating to have an ESC that can auto-compensate for dwindling battery voltage, then you ought to seriously think about why it is OK to have a automatic pressure regulator in a recip.  There isn't much difference, other than one is wet and the other is dry.  And the other key point about having an ESC with this feature is that it doesn't do anything to alter the piloting of the model based on the external conditions that the model is encountering. All it is doing is de-rating the output of the the battery to make it consistent throughout its useful operation range.  

Ed

To: nsrca-discussion at lists.nsrca.org
Date: Wed, 3 Mar 2010 13:58:30 -0500
From: rcmaster199 at aol.com
Subject: Re: [NSRCA-discussion] Max volts 

Dave,

I would argue that the ESC has the sensor built. It isn't a sensor in the sense of a mag pick up such as CDI devices have. It is rather an exact frequency determination to which the motor is driven. It is simpler and hidden. Should we go back on mechanical advance....God no./

I think the CDI electronic advance is similar to today's digital servo. The former advances spark pulsing based on rpm and the latter advances motor output torque based on input load. Whether each violates, not sure. Needs more thought and comparison to the rules. My first take would be to say NO because the magnitude of adjustment is fixed

Matt

----- Original Message ----- 

From: Dave 

To: 'General pattern discussion' 

Sent: Wednesday, March 03, 2010 9:47 AM

Subject: Re: [NSRCA-discussion] Max volts

Matt,

One more thought/consideration/question –

Is electronic ignition with variable timing advance illegal?  Essentially the RPM is sensed (through a sensor), and as RPM increases, the timing is advanced.  The ESCs of today do the same function…they advance timing as RPM increases, but do so without sensor.  Should we go back to sensors and mechanical advance devices?

Regards,

Dave

On Mar 2, 2010, at 8:15 AM, rcmaster199 at aol.com wrote:

I had a brief conversation with Dean Pappas on this subject recently. Dean explained that some folks have been advocates of programming the ESC to do some footwork at various stages of battery use. He explained to me just how easy this is to do physically. It seems a few have mentioned something similar in this thread.

I am not that concerned about raising the voltage of the battery as I see this as a somewhat clear violation of the FAI code. I am more concerned about what and how the ESC is "programmed" . I would like for some one with the electronic/software pedigree to explain to me how programming adjustable rates of voltage potential and making these adjustments automatically, does not constitute a programming violation within the rules as they exist today. 

When the rules were written, we were clearly dealing with RADIO pre-programmed sequences and the like, no gyros, etc. However I would argue that rate auto adjustments that are definitely possible with the ESC's of today, also qualify as a violation of said rules. Someone should sit down and think this through...I could be convinced otherwise but it needs to be a good argument

MattK

-----Original Message-----
From: Anthony Romano <anthonyr105 at hotmail.com>
To: nsrca-discussion at lists.nsrca.org
Sent: Tue, Mar 2, 2010 8:29 am
Subject: Re: [NSRCA-discussion] Max volts

Keep this line of thinking in mind next time we talk about weight limits! Or any other rules proposal.

Anthony

> From: burtona at atmc.net
> To: nsrca-discussion at lists.nsrca.org
> Date: Mon, 1 Mar 2010 22:45:57 -0500
> Subject: Re: [NSRCA-discussion] Max volts
> 
> OK, So I have a question. Is knowingly and purposefully violating the intent
> and letter of the rules to gain a performance advantage called cheating?
> ....... Just asking!
> Dave Burton
> 
> -----Original Message-----
> From: nsrca-discussion-bounces at lists.nsrca.org
> [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of James Oddino
> Sent: Monday, March 01, 2010 7:16 PM
> To: General pattern discussion
> Subject: Re: [NSRCA-discussion] Max volts
> 
> I have the functional concept that solves the rules problem. Picture a 10S
> pack positive lead wired to the common of a switch with two poles, a piece
> of wire connected from one pole to a pole on a second two pole switch with
> its common connected to the ESC. Between the other two poles we place our
> 11th cell. When the 10S pack is above 37.5 volts the 11th cell is bypassed
> and when it is below, like it will be during vertical maneuvers late in
> flight, the 11th cell is put in series to boost the voltage to up to 41.7
> volts. At no time is the voltage over the spec.
> 
> Having said that, I believe the 10S system provides adequate power with the
> right motor at all times of flight even if the voltage drops to 35 volts.
> 
> Jim
> 
> 
> On Mar 1, 2010, at 8:59 AM, Bob Kane wrote:
> 
> > Going higher and regulating down would be against the rules, the max volts
> is still limited to 42.56. 
> > 
> > Bob Kane
> > getterflash at yahoo.com
> > 
> > 
> > --- On Mon, 3/1/10, krishlan fitzsimmons <homeremodeling2003 at yahoo.com>
> wrote:
> > 
> >> From: krishlan fitzsimmons <homeremodeling2003 at yahoo.com>
> >> Subject: Re: [NSRCA-discussion] Max volts
> >> To: chad at f3acanada.org, "General pattern discussion"
> <nsrca-discussion at lists.nsrca.org>
> >> Date: Monday, March 1, 2010, 9:54 AM
> >> 
> >> Couldn't we go to a higher voltage and
> >> regulate it back down? A contstant 42.56v would be nice!
> >> 
> >> Chris 
> >> 
> >> 
> >> 
> >> 
> >> 
> >> 
> >> 
> >> 
> >> 
> >> From: Chad
> >> Northeast <chad at f3acanada.org>
> >> To:
> >> nsrca-discussion at lists.nsrca.org
> >> Sent: Sun,
> >> February 28, 2010 8:48:48 PM
> >> Subject: Re:
> >> [NSRCA-discussion] Max volts
> >> 
> >> You would be at about 50% capacity at 3.85 ish volts/cell
> >> (resting open circuit), so unless you up the capacity you
> >> will have a pretty restricted flight time.
> >> 
> >> Chad
> >> 
> >> On 10-02-28 9:25 PM, Ron Van Putte wrote:
> >>> That stirs a wild thought in my brain. Fully
> >> charged packs don't stay at 4.2 volts per cell very
> >> long. On the other hand, once the initial charge
> >> voltage is burned off by a constant load, the voltage loss
> >> curve "flattens out". What if you put fully
> >> charged 6S and a 5S packs in series and "burn them
> >> down" to 3.869 volts per cell (a total of 42.56
> >> volts for an 11-cell pack) so they were legal for
> >> use. Would the voltage of this depleted 11S pack be
> >> higher than a fully charged 10S pack at the end of a typical
> >> flight? If the end-of-flight voltage might be
> >> significantly higher for the 11S pack vice a 10S pack, it
> >> would be worth investigating, even considering the extra
> >> weight of the additional cell. Come on you electronic
> >> gurus, show me where I'm wrong.
> >>> 
> >>> Ron Van Putte
> >>> 
> >>> On Feb 28, 2010, at 10:00 PM, James Oddino wrote:
> >>> 
> >>>> What comes after ...? Does it specify a load
> >> or any other conditions? Is it measured during the
> >> noise test and have a minimum value?
> >>>> 
> >>>> Just stirring the pot, Jim O
> >>>> 
> >>>> 
> >>>> On Feb 28, 2010, at 5:21 PM, John Fuqua wrote:
> >>>> 
> >>>>> No its not (assuming we are talking RC
> >> Aerobatics). Try page RCA-2 para 4.1
> >>>>> which
> >> states "Electrically-powered model aircraft are
> >> limited to a maximum
> >>>>> of 42.56 volts.."
> >>>>> 
> >>>>> -----Original Message-----
> >>>>> From: nsrca-discussion-bounces at lists.nsrca.org
> >>>>> [mailto:nsrca-discussion-bounces at lists.nsrca.org]
> >> On Behalf Of Ron Van Putte
> >>>>> Sent: Sunday, February 28, 2010 7:07 PM
> >>>>> To: General pattern discussion
> >>>>> Subject: Re: [NSRCA-discussion] Max volts
> >>>>> 
> >>>>> It's in the general rules, not in the R/C
> >> section.
> >>>>> 
> >>>>> 
> >>>>> On Feb 28, 2010, at 6:50 PM, Jim Quinn wrote:
> >>>>> 
> >>>>>> Where can I find the rule
> >> for max volts?
> >>>>>> 
> >>>>>> 
> >> _______________________________________________
> >>>>>> NSRCA-discussion mailing list
> >>>>>> NSRCA-discussion at lists.nsrca.org
> >>>>>> 
> >> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
> >>>>> 
> >>>>> 
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> >>>>> 
> >> _______________________________________________
> >>>>> NSRCA-discussion mailing
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> >>>>> NSRCA-discussion at lists.nsrca.org
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