Compass 4926-510 SZ - Flight Report

[Rob43]

My system seems battery pack limited. I think the GA packs are reliable, and run cool, but don't provide as much punch. Not sure why. They just don't. I'd like to try some TP65C packs to see, but not worth the $500 to find out.

[Bubba Gump]

Rob how you liking the new motor? I finally getting my 7hv this week as soon as the new shipment for Nankin gets out of customs this week. I'm gonna be running it with vbar gov. I'm looking at running 1800hs and running light set up with gens ace 4000s that I already have.

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[BakedMopar]

I have logs from mine but I don't have a 45 size xera or scorpion to compare it too. I also don't fly hard enough to see the difference between this motor and the Hacker that was in there before. The only difference for me is at lower rpms it will hold the headspeed better. Do I think it's a good motor? Yes. Can I make use of its power? No. Lol

[Stolla]

Originally Posted by Rob43

My system seems battery pack limited. I think the GA packs are reliable, and run cool, but don't provide as much punch. Not sure why. They just don't. I'd like to try some TP65C packs to see, but not worth the $500 to find out.

What pinion youre running Rob, if lipos still cool maybe you can run a t bigger pinion to get the jive use headroom more efficiently. I find my 4035 yy handwind, 510kv came alive on 15t

[Rob43]

Originally Posted by Bubba Gump

Rob how you liking the new motor? I finally getting my 7hv this week as soon as the new shipment for Nankin gets out of customs this week. I'm gonna be running it with vbar gov. I'm looking at running 1800hs and running light set up with gens ace 4000s that I already have.

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Hey Forrest! I think the 4926 is a great motor, and I, for one, believe the light setup is very suitable to the 7HV, and for me, so far, more fun. Plenty of practical power.

Originally Posted by Stolla

What pinion youre running Rob, if lipos still cool maybe you can run a t bigger pinion to get the jive use headroom more efficiently. I find my 4035 yy handwind, 510kv came alive on 15t

I tried the 15t. I could hold at 70% throttle at 2250 headspeed, and the GA 30C packs came down warm. Just warm, not hot. 100f or so. Maybe someone watching me would say "Wow" is that thing crazy, but from the sticks, it just made more noise and was a little faster. I'll say this, the motor was relatively cool afterwards. Maybe 120F. Jive heat sink felt like maybe 110F. Was 80F outside air temp.

At this point, I plan to get Spyder 30C 12S stick, run 13t at 65%, and maybe try some 710-713 blades. I have some Rotor Tech 115mm tails on the way. I love how quiet the Rails are, but I'd like to really try a low disc loaded bird to explore the smoothness a bit.

[OICU812]

While observations in both sight, sound and so fourth are valuable in motor evaluation numbers rule the final roost. DO you by chance have a Eagle Tree or FDR of some sort to get some graphs can clearly show HS losses, current draws, max spikes and so fourth? That would be very valuable in such cases here. Interested to hear more, thanks.

Ive tested countless motors and "often" was VERY suprised once numbers were shown clearly to compare, what sometimes seems to be king is often the kings fool. Not saying this one is, it "sounds" good but some good HARD data would surely compliment the stories nicely.

[myrseth]

I have to disagree, you can get sky high numbers on a motor and still underperform, it depends how efficient the motor is and if its geared correct ++

[OICU812]

I'll strongly disagree with you Numbers, GRAPHS are ONLY way to clearly know on a given system how it handles and process the power. A 100% optimum system is your goal, at least it is mine and it is serious business and inquiring minds want to know

Of course gearing is all important, and of course you can get microspikes, bursts etc, but the point is the averages and all data surrounding it, more then a few lines makes a story is what I am saying here.

In conclusion there is NO free lunch, with great power comes great draw, its key to know those spikes, their length and to better evaluate the power to "worth" ratio in regards to electronics abuse from the esc to packs and so fourth.

[Rob43]

As an engineer, my experience is that the data should mostly reflect the system performance, and help point towards the desired improvements. As a geek, I think I'd like to learn more how this system is performing, regardless if I can fly it hard enough to extract the max from it. Common sense may or may not play out in optimizing it for me. To me, both Klaus and Shawn are both correct. The numbers could be misleading at times, but without any numbers, there's nothing to share.

I need to understand the best logging method to move forward. It seems to me that the J-Log would be best since it's not in series with the power system. Eagle Tree looks much simpler, but has some current limitations.

[GimpyGolden]

JLog is beauty.
Not difficult at all.
If you get one and need help there is a forum for it here. Tom the designer is very helpful.
Shoot me a PM as well if you need further help.

[heraldo]

What sort of currents are you guys pulling? I only have a SJ Hawk 120HV esc, will I need to upgrade. I fly 3d but nothing hard.


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[Stolla]

incidently the fusionhawk is one of the best esc's current wise, gov is no good but works fantastic with vbar gov in heli mode actually better than the digested plane mode.

Regarding numbers its true that a bad setup can show high numbers amp wise if a motor bogs for instance, but you will see the rpm drop at same instance. Numbers are indeed the only thing that will truly show what's going on, but most people think if they get a200 amp spike they have a8 kw motor, not so!, you have to look at the overall picture, average amp draw, rpm decay under load, pwm percentage.
Jlog is a fantastic tool and imop crucial for a perfect setup, I was flying my helis thinking my setups were perfect till I saw the pwm percentage hitting 100% too often, you can easily see on the figures how the rpm drops as soon you hit max due to the gov running out of headroom but not noticeable by ear or sight as its not real bogging just more rpm drop, with strong motors you won't pick it up except through logging
The problem with logging is people tend to misinterpret the figures, when comparing data between different motors, setups etc its very difficult as you need exact same conditions gearing headspeed etc to get an indication of how they compare.