Brenner

Hey Peter,

The 650 is robust to any ambient temperature. It runs ice cold, so if heat rise is a concern, the 650 will definitely solve all of your problems. I think that you could easily fly it in ambient temperatures up to 45C and above.

The 650 has less power than the 600, and maybe the same, or slightly more than your current setup, which is a mild setup.

The only downside of the 650 is that it weighs 70g more than the 600. A V4 system with a 650 motor will probably end up saving you about 130g over your existing system.

Just contact Mike Mueller at f3aunlimited. He can make arrangements for whichever motor you prefer.

Brenner ...

DaveL322

Bill,

AmbientF +100F is in my experience a concerning increase in temperature......the caveat being how the temperatures are measured can have a substantial impact. Can you advise how you are measuring temperature?

Given the variability of the case materials and finish on most electric motors, I've standardized my practice of measuring motor temps by using an IR gun and measuring the temperature of the rear motor shaft. Most of my Neu setups ran +40-60F, and the Pyro 650 (in cold weather) has been +20-30F, while the Pyro 600 typically shows +40-50F.

If you are able to directly (and consistently) measure the windings of the motor, the temperature will certainly be higher than measuring the rear motor shaft.

rgreen24

My Feedback: (6)

How long do you let your motor sit to cool, before you fly again?

Bubblehead575

Dave

I was measuring the motor shaft and motor can with a small IR temp meter just a few min after landing, There was not a lot of difference. I am going to direct more air flow over the motor to see if that helps. I am also going to try and download the data from the Mezon 95 to see if I note anything unusual.

I normally wait 30+ min between flights. We have a few people flying together.

DaveL322

Bill,

I would definitely look at improving your cooling to your motor. From the ESC side, PWM can affect motor temp. If the ESC is running cold, you might be able to increase PWM and get a small decrease in motor temps (and a small increase in ESC temp). Improved ducting to (and from) the motor should get you a substantial reduction in motor temps.

And...if the ESC is running cool, and you have plenty of power, increasing the compensation factor on Throttle Tech is likely to be an overall improvement for your setup (but it will likely slightly increase ESC temps, or temps on the ESC capacitors).

Between flights...I often fly back to back flights....rarely does the motor increase measurably with multiple back to back flights.....it actually is hottest (on the surface or on the rear shaft) 5-10 minutes after a flight when the internal heat of the motor has "soaked" to the exterior.

Brenner

A couple of tips for installing the V4 Contra Drive:

1/.. I do not recommend running the motor by itself. Without a load it can very easily over rev, and the mounts are tuned for the total weight of the complete system.

Running with just the motor will make the system only have about half the total weight, which will raise the natural frequency of the system up way too high.

The mount is tuned so that the resonant frequency of the system is as low as possible. The Drive will pass through this resonant frequency as you accelerate the motor, and then become very smooth. This is how vibration isolation systems are designed.

2/.. We have had one report of the rear support needle bearing backing out of the rubber grommet. In order to prevent this we recommend using a few drops of CA to lock the needled bearing into the grommet.

3/.. Up until now we have been shipping the rear support needle bearing unlubricated, but from now on we plan to add a few dabs of grease. If the Drive you receive has an unlubricated rear support needle bearing, please add a few dabs of grease to it. We are using the same grease that goes in the Drive. (Rheolube 374A)

TonyF

My Feedback: (92)

I am running the 650 in my V4 and I run the same props as you. I also run the same gear ratio in my V3's as you. I feel they are very similar in performance. Only thing is that the 650/V4 combo needs a much flatter throttle curve. It's power comes in much sooner then the Neu/V3/Castle ESC. BTW, I am also running a Castle in the 650/V4 model with no issues.

Brenner

Hey Tony,

You're right. I forgot to mention the throttle curve.

I've flown both the 650 and the 600, and both motors required a linear throttle curve.

My throttle curve has a sharp jump at the beginning, and from about 15% or so it's linear all the way to full throttle.

Brenner ...

mups53

My Feedback: (41)

Guys I just finished listing the new Falcon props we have available:
http://www.f3aunlimited.com/airplane.../falcon-contra
We're on a very limited stock as we get started with Falcon.
We still sell all the Original Contra props on the site now you have a different choice.
Thanks for your interest.
Mike Mueller
F3AUnlimited.com

mups53

My Feedback: (41)

What's the most popular ESC for the two motors?
Mike

Brenner

Hey Mike,

I notice that you're selling the Falcon and the Mejlik props $0.05 cheaper than our original brand props.

I guess we're going to have to lower the price to remain competitive.

Brenner ...

rm

My Feedback: (27)

Mike's (Gaishan) gonna have to take a pay cut.

Brenner

That's going to be a harder sell ....

mups53

My Feedback: (41)

For the sake of all involved I am enacting a price increase on the Falcon props to $100.04
I can't take the pressure.
Mike Mueller

NJRCFLYER2

My Feedback: (42)

Dave, I'm not following how increasing the Throttle-Tech compensation factor would make the ESC or ESC caps run any warmer. It's resulting in a lower throttle setting for a given stick position, so it seems like it would run about the same temp, if not slightly cooler. I realize that the overall efficiency of a motor/gear combination that has a lot more power than you would need can be considered less efficient than one that is better matched to the real need, But I don't see any direct correlation to throttling back a little more on average and having the ESC run warmer. What am I missing?

NJRCFLYER2

My Feedback: (42)

Dave, thinking on this a bit more, when you take an overall power delivery system (battery, ESC, motor) that has excess power on tap and then limit its upper range to produce only what a lesser, but totally adequate system can produce in its optimal power range, then yes, there may be more heat generated in the "killer" system as a result of not running in it's optimal power curve, Is that along the lines of your reasoning?

Brenner

Hey Bill,

I'll let Dave comment on his comments, but as far as motor efficiency is concerned, The motors that we use aren't going to see a significant reduction in efficiency if they are throttled back by the amount that we do when we fly. This is because in the ranges that we run, motor efficiency will typically increase a little as the motor current is reduced. This because I^2*R losses are lower when the motor current is reduced.

You can test this out by using one of the many motor performance calculators that are available online. The one I use is Ecalc. (http://www.ecalc.ch/)

See below for a typical analysis from this website.

On the other hand, my understanding is that an ESC will run the coolest when it's running at full throttle, because at full throttle it's primarily just passing the battery voltage on to the motor.

However, when an ESC is throttled back, the IGBTs in the ESC are switching on and off, and since they take a finite amount of time to switch like this, there are power losses while they are switching, which results in heat generation.

NJRCFLYER2

My Feedback: (42)

Speed controllers are a PWM (pulse width modulated) system. The MOSFETS switch on and off at any and every throttle setting / RPM. To turn a prop faster, the motor gets longer pulse widths of on time from the speed controller to generate a longer magnetic impulse to motivate it to turn faster under some load condition. When the MOSFETS are on, they are all the way on, i.e., full battery voltage to the motor windings every time the switch on is thrown. When they are off, they are all the way off. Other than extremely brief switching times (discussed below), there's no in between. They do not regulate voltage to the motor. The motor windings get all or nothing, just depending on what position they’re in during each commutation period. If it didn’t work this way, i.e. if some type of voltage regulation system were being used, you would need a whopping big heatsink that wouldn't even fit in a Pattern airplane. And you would need batteries with much more capacity than what we carry now, just to heat the heatsinks and throw the heat overboard.

At higher RPMS the average time that MOSFETS are on is longer than at low RPMS. They are also being switched more frequently. One of the two main reasons for heat being generated in the MOSFETS is the effective on resistance when they are conducting, in which ohms law basically applies (ignoring reactance and reactive power here). Power MOSFETS used in speed controllers have very low on resistance, a small fraction an ohm, but at the current levels that occur while on, even a fraction of an ohm results in some heat generation that can’t be ignored. The lower the MOSFET's on resistance is, the better, but make no mistake, the more average time they are on, the more heat is being generated by that on resistance factor. When a MOSFET is off, its DC resistance is very, very high and for all practical purposes, you could consider it infinite for this type of discussion. That just means that the power dissipated in the MOSFET while off is insignificant.

Another significant consideration when it comes to heat generation inside each MOSFET is its switching time. Consider switching a MOSFET on. It goes from essentially zero current to a very high peak value within a few dozen nanoseconds. Quite fast, yet due to the slope of the switching current (where current rise is measured against time), it generates considerable peak power inside, but for such a fleeting moment that the average power is not high at all, and all is well. However faster switching rates (more switching events per second) at higher RPMS yield higher average power consumption in the MOSFETs, just because there are more of those fleetingly short switching events per second, each contributing a small bit to the average power consumption in the MOSFET, hence more heat to dissipate. It’s all manageable, but it’s just what happens. The ideal state would be if the rise and fall times for switching were zero. Then no heat would be generated during switching, but that is not the case in real applications.

Sorry for that being so long winded, but all that is what is behind why I’m puzzled by the idea that the speed controller would run a little warmer at a slightly reduced power setting. It may be the case, I just don’t understand why yet. I want to see what I’m missing.

Brenner

Hey Ed,

Excellent explanation!

Has anyone actually seen their ESC get warmer when it was throttled back. I definitely agree that modern ESCs are designed to be run at part throttle without issue, and I can't think of anyone actually claiming that their ESC is getting noticeably warmer when they run it at part throttle.

I know that it hasn't been a problem for me.

Brenner ...

Bubblehead575

Great Discussion,

I pulled the data from the last flight and the ESC temp was 66*F and max current was 79 Amps. I have increase airflow around the motor by adding a little more baffling. I have also increased the Throttle Tech setting from 30 to 45 to reduce the max throttle and hopefully my mah out. Snow has kept me grounded so I have not had a chance to check the effect of the increased baffling. Hope the weather will improve and let me get a couple of flights in next weekend.

NJRCFLYER2

My Feedback: (42)

I'm probably not giving proper consideration to the effect of back EMF in reducing current flow when switching occurs.

jankulus

Hi Brenner.

I tried contacting you via Facebook with no result. I am interested in V4 contra in black anodized version. Mike from f3aunlimited said to ask you directly.
Is it available in a predictable time?

My mail: [email protected]

Cheers,
Jan

Brenner

Hey Jan,

We still offer anodized Drives. Mike just hasn't modified his website yet to include a color option.

What we plan on doing with the V4 is offer the choice of black,purple, red, gold, or black for an extra $100 charge. We can also offer blue or green, which are special order colors, for a $300 charge.

Also, if anyone has a special custom color that they would like, we can ask our supplier to try and match a sample, but there are no promises that they will get as close as is needed. If someone wants try this, we will have our anodizer quote us the cost, and we will pass this cost on to the customer.

Any kind of color anodizing will require a three week lead time,because we are trying to limit our stock of colored parts.

My suggestion is to tell Mike to add a color option to your order, and add a $100 charge.

If he is unwilling to do this for you, we can sell to you direct. You can contact me through RCU using the private message feature.

Brenner ...

Bubblehead575

Got 7 more flights in today, and spent them trying to get my Agenda trimmed.

I checked the motor temps after the flights and the new baffling made a huge difference. Air temp was about 60*F and the Shaft temp was on 85*F The Can was hitting about 110*F which is consistent with what I have seen with my Neu.

I dialed the Throttle tech to a Compensation Factor of 37 and I have more then enough power.

I will have to wait until I am done trimming to see how my consumption is on a sequence.

Brenner

That sounds much better. The 600 motor trades off heat rise for weight, but it is still better than the Neu f3a motor, which is pretty good as far as heat rise is concerned.

However, the fundamental difference between the two is that the Neu weighs about 380g, whereas the Pyro 600 weighs about 230g. Also, the 600 has more power, and has a more linear throttle response. You can also use the air coming out the back of the rotor to cool your ESC.

Brenner ...