13S 5000!!

[zguy]

Disclaimer-These are real life results on my Logo 700 as delivered. I’m not recommending doing this and am simply sharing information to help anyone who may be wishing to pursue similar results. YMMV!

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Thanks to the generous loan of two 7S 5000 packs by RC Depot , I was able to test 13S 5000 on my Logo 700 yesterday and am very pleased with the results.

To recap, the 4525-520 that shipped with my Logo 700 appears to be closer to a 500kv motor based on the hover head speeds. This is well within the production tolerance, but also yielded less than 10% headroom for the governor. This resulted in the 12S batteries running at, or near, 100% throttle in flight at 2050 rpm and gave little to no reserve for heavy/sustained collective moves.
In addition, the AUW of my Logo 700 on 12S is 12.6 lbs and using a power system typically targeted for helis that weigh 1-2 pounds less is not going to result in an impressive power to weight ratio.

Now, before anyone gets upset….
The Logo 700 as delivered has adequate power for all 3D flight, as evidenced by the stellar flights performed by the Mikado team pilots. I believe that if the motor was closer to its stated kv, excellent 12S packs and good collective management are used that the 700 will perform just as in the videos.
That being said, I’m not at that skill level and simply want my new Logo 700 to perform as well as possible and in a similar flight envelope to my other somewhat overpowered helis. The goal is to have fun!!

So, some may have read my 14S thread and ultimately I can envision a high performance setup using 14S packs and an appropriate motor. (This also may become a 750mm machine.) The stock motor and gearing is not well suited to 14S and so I decided to split the difference and try 13S!

As can be seen in the chart below, 13S is the sweet spot for governor headroom when trying to run ~2050rpm head speeds. As opposed to the 12S setup, 13S has ample reserve power to support sustained collective (and poor collective management skills!). It really “woke the bird up” and makes it fly much more as I had hoped.



Adding a cell to the Logo 700 adds 2.1% to the AUW, but also adds 8.3% more power on board. As mentioned above, a heli that weighs this much can use the extra energy. I did try head speeds from 1800 to 2200rpm and found that at 2075 that the added weight was not noticeable, but the additional power certainly was. 2100-2200rpm did not contribute much more other than shortening flight times and making more heat. At 2075, the motor and ESC are each running about 10F higher than on 12S at 2050. 1900 rpm is the sweet spot for sport flying on 12S and is probably the highest that should be continuously run on 12S. 1900 on 13S is also perfect for sport flying, but this did result in the only thermal ESC warning during all testing. This is likely due to the low throttle percentages at 1900 on 13S and the increased switching losses. I will be adding a heat sink just for such occasions.

Oh, yes you can switch between 12S and 13S at will and without changing any settings. Very nice flexibility!

Pros:
Heli can now fly aggressively with adequate power, governor headroom and with less strain on the batteries.
Flexibility to run 12S/13S at will.
Can now wait and save for full upgraded power system.

Cons:
Adds more weight to an already heavy machine.
Can’t parallel charge 6S and 7S together. (Not a big deal for dual port or separate chargers.)
Will have to answer endless questions on “13S ?!?”

So, if you have access to a 7S 5000 pack, combine it with a 6S 5000 and give it a try.

Blade testing next week…….

[OICU812]

Interesting but the gearing will work for 14s to like you said 520 bit much...460-490 kv will do in that spot. I don't have any 7s 5000 but I would surely try if had.

Very nice breakdown and report!!!

[heliaddict2424]

Nice job zguy that looks like allot of work you went to. I must admit though I think the Logo 700 stock setup is pretty darn good headroom wise and everything else. I think that you will find in Kyle Dahls 3d Masters freestyle flight that headroom is not an issue. If it was good enough to win 3d Masters then its good enough for most..just saying.

[zguy]

Originally Posted by heliaddict2424

Nice job zguy that looks like allot of work you went to. I must admit though I think the Logo 700 stock setup is pretty darn good headroom wise and everything else. I think that you will find in Kyle Dahls 3d Masters freestyle flight that headroom is not an issue. If it was good enough to win 3d Masters then its good enough for most..just saying.

Hey Shannon,
No argument here, unfortunately few of us fly like Kyle.

The motor kv and gearing in my Logo 700 does not have adequate headroom to run ~2050 rpm on 12S as shown in my testing. As I'm sure you already know, for any power set up the governor needs headroom to work. This allows the batteries to hold a reserve and provide extra power on demand. Going 13S provided a simple, lower cost solution (vs. upgrading the whole power system) to make the heli fly better for me and I'm simply sharing the results.

I wish that more people would provide actual data to support their opinions and am very curious to know what other's beginning of flight HS is to indicate motor kv. Maybe mine is an outlier?

Also, the Dahl's have said that they have not had a production kit and may, or may not, be using the same production batch motor?

Really looking forward to others sharing their experiences. Isn't that what these forums are for?

[dahld]

Hey Rob, another possible option to get where you want to go with your motor, is trying an 18 tooth pinion vs. the stock 17 tooth. I can send you one if you want. Send me your address via e-mail if you want to give it a try.

(-: Dave

[Tenguru]

Thanks for posting this info.

If your motor is a lower kv than advertised, have you considered running a pinion one tooth larger?

Also, what was the flight duration for each test flight? That would give more meaning to the "End of flight HS at 100% throttle" column of data.

[zguy]

Originally Posted by dahld

Hey Rob, another possible option to get where you want to go with your motor, is trying an 18 tooth pinion vs. the stock 17 tooth. I can send you one if you want. Send me your address via e-mail if you want to give it a try.

(-: Dave

Thanks Dave!

Upping the gear ratio by 6% would provide the needed headroom on 12S, but my guess is that the power system will be less happy working harder at the higher gear ratio. My formula to make helis fly fun for me is to use the smallest pinion possible to provide a minimum of 15% headroom on a slightly over-powered power system. The 12S is not quite enough for the weight.

Still "one test is worth 1000 opinions" is my motto and I'd like to try it.

Also, I did read you comments on the other thread and agree completely that if a pilot at Kyle's level uses the 13S power to the max for the entire flight that it will be too much heat. For me with mixed high/low demand maneuvers, it seems to be OK...for now

This is starting to get fun!

[zguy]

Originally Posted by Tenguru

Thanks for posting this info.

If your motor is a lower kv than advertised, have you considered running a pinion one tooth larger?

Also, what was the flight duration for each test flight? That would give more meaning to the "End of flight HS at 100% throttle" column of data.

Pinion question answered above.

The flight times were 4:00 for the <2075rpm tests and 3:30 for the >2100rpm tests. The mAh returned to the packs was 3597 to 3839 and end of flight voltages were ~3.75v/cell.

It would take 10x the amount of flights to get proper averages, but I did my best to get consistent results in the limited time I have.

[JCLG]

Hello everyone,hello Kyle

With the LOGO 700XXTREME/520KV/YGE160/VBAR GOV in 3D flight:

I would want to know clearly if it would be more interesting to put a 18T pinion and have more flexibility with the headspeed of the main rotor and be sure to have 1900 to 2100 rpm with 12S?
Or put the standard 17T and have 2050 rpm max.

For information we can use the max headspeed few time but for pleasure(i know that the batteries don't like but....)

I 'll receive very soon the LOGO 700XXTREME and i have bought also the 18T pinion in case of..
I don't forget also that we use 713mm main blades instead of 693mm like other 700s.

I ask the question to Kyle or other pilot which perhaps have compared the 2 pinions 17T and 18T.
Thanks for answerme.

[dahld]

@ JCLG,

Your quote, "I ask the question to Kyle or other pilot which perhaps have compared the 2 pinions 17T and 18T."

Last winter when we first got the prototype Logo 700's, all we had was the 18 tooth (they were available because the Logo 800 used them). After many flights, we asked Mikado for a 17tooth to test (which they then produced), as we felt the 17 tooth gearing might allow the motor to unload a little and run cooler. The system with an 18 tooth we felt ran just a little too hot for our liking, and in the end, Kyle settled on the 17 tooth.

Now as been discussed before, very aggressive flying styles can often expose a drawback in a power system (usually meaning they run too hot because of the watts you're pushing through the system). That same system when flown just a little bit easier, might prove to have some advantages, like holding head speed a little better, etc., whatever. I think this could very possibly be the case with the debate over the 17 and 18 tooth pinions on the 700.

Now Kyle thinks the 17 tooth provides enough head room, holds head speed well enough, and the gearing of the system helps things run cooler as a benefit. I mean, he could have selected for the combo the 18 tooth, if he thought it offered any huge advantage. To some it might (and we're all OK with that...no hurt feelings if that's the way some want to go). But Kyle uses what he thinks runs the best overall, which although may not be perfect for every pilot and flight style, works pretty well.

But since you've got an 18 tooth coming, give it a shot. Nothing really "bad" can happen with it from experimenting.

(-: Dave