RunRyder RC Helicopter Topic - DH400 Tech Test part 2 (stock blades)

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e-Zoom, Shogun, Dolphin > DH400 Tech Test part 2 (stock blades)

The real Ingo
Senior Heliman
Location:

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DH400 test is goin' on....
I did a test with the tach and tail mounted.
I generated 500gr of lift with stock blades.
I changed the timing this time.
I was expecting this behaviour changin timings but now I know where high timing start to be better.

Let me say that rpm may be wrong because the tach works bad with artificial light, but I believe I trick it using a DC bulb.
Sometimes it showed very out of scale values so I will repeat the test in a sunny day (actually it's raining).
I took at least 3 readings for each value showed here.

rpm - Amp - Amp
Head - HT - STiming
1300 - 6.1 - 7
1400 - 5.9 - 6.6
1500 - 5.8 - 6.5
1600 - 6.2 - 6.4
1700 - 6.7 - 6.4
1800 - 7.4 - 6.8
2000 - 8.7 - 8.4
2100 - 9.9 - 9.4

I made a graph with excel but do not know how to post here.
Also I have pictures that show amperometer, lift and rpm.

From 1300 to 1600rpm high timing advance perform much better.
1500rpm with high timing is the best efficent hovering I ever performed with stock blades. Going up with pitch at 1500 will make your hely climb like a rocket, you have a BIG reserve of power (I'm at 50% hovering at 1500rpm).
The problem is that blades are coning a lot when I apply full pitch.
I will make a test to reach the best climb rate, that is for sure different from 1500.

Over 1600 rpm standard timing will be the choice, but you will lose max power, I mean less climb due to less power reserve.

I did not made any test over 2100 because IMHO do not worth the power you spend (at 2200rpm you will have almost half the duration compared to 1700rpm) at least with stock blades (MS carbon blades are here ready to test). I do not want to pay 3A for 300rpm.

I did'nt try the low timing because...I don't know why, I'm tired and want to make other things. I will do that.
First trials with LT showed some problems (esc do not drive properly the motor) but I'm not sure.
If it works simply the curve (make them with excel) is shifted on the high rpm side and raised , the same that happens going from HT to ST.
Drag will worse the things so probably it do not worth but...theory is not enough to say that this is true.

Conclusions:

1500rpm HT the best efficency.
1700 - 1800rpm ST the best compromise looking for better cyclic response.
Any rpm over 1800 will be just heating your batt motor and esc to have better cyclic and say to your friends "my zoom fly at more than 2k!!"
and remember to turn off your heaters, you don't need them ;-P
You can use piccolo paddles to have the same cyclic effect instead of running high rpm.
If you need more than 1800rpm look for another setup (let me work, you will have also this test, if someone give me the parts :-).
Ingo

01-23-2005 Over year old.

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turboomni
Elite Veteran
Location: 63 Rambler Down By The Dumpster

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Great work Ingo. I do have a few thoughts. I'm assuming you're still using the 8T pinion. You said between 1300-1600 @ high timing advance was much better than standard timing. This seems to be the sweet spot in the motor I guess. I also wonder what rpms is the motor turning between 1300-1600 headspeed? You also said it had a big reserve in power at this setting.
I would also be very curious to see how this combo would work with a 9T pinion as I feel 1500 rotor speed is slow compared to what I'm used to. That way you keep the motor in your newly found powerband but up the head speed abit.Does your gyro and tail have enough authority to control the tail during those climbouts at such a low headspeed?
Very interesting work you're doing!

01-23-2005 Over year old.

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HugeOne
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Location: Quebec, Canada

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Need to do the same with the himaxx, lots of people is using this motor. But don't have a tach.... I'll find some way...

Raptor e620 w/V-bar, Tango 45-06, Phoenix 85HV, TrueRC 12S1P 4000mAh

01-24-2005 Over year old.

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The real Ingo
Senior Heliman
Location:

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Yes I'm using the 8T.
9T will keep the motor rpm too low, 8T is perfect. If I can I want to try 7T but never saw it.
1300-1600 HT is better than ST but not so much, if you really don't like the cyclic response go with 1700-1800 ST (you will lose 1/7 of duration no more).
you can see the differences in terms of amps in the datas posted before.
Don't know if the tail is ok, I know about climbout because it generate lot of lift on my balance.
My way to adjust Tail speed is to find the rpm that keep my gyro gain very close to max.
Lot of people want lot of rpm but they have to lower the gain, finally they have the same authority, this is the theory.
I'm not into 3d so I?m setting up my hely to have very good and efficent flight. I care about everything, one I decide my headspeed I will adjust the cyclic to have the response I need and the same for the tail.
My tail is ok from 1300rpm, under 1300 I do not like it.

HugeOne, You do not need a tach.
Use the 60hz of your light and watch until blades look stopped, this is 1800rpm, also find the 900rpm. look at your throttle % and assume the relationship between % and rpm to be linear. use gov mode.
Ingo

01-24-2005 Over year old.

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HugeOne
Key Veteran
Location: Quebec, Canada

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The relationship between %gov and HS is not linear, it's kind of exponential look here:

http://www.fraserker.com/heli/zoom/

Thank for the 60hz trick.

I doubt the Himaxx will need less timming advance than the 400DH because it have less poles. This motor is surely less efficient at low speed than the 400DH, so you got to run slightly higher HS compromizing even more the effiency due to low drag.
Conclusion:
Himaxx

400DH

-Hugo

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01-24-2005 Over year old.

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c/f
Senior Heliman
Location: Evansville, IN, USA

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Ingo,

Same setup 400DH/CC25,

I too found that low timing would not run the motor properly, never tried to figure it out just went back to ST/HT.

I had started with the High timing and only after I wanted to improve duration was it suggested and tried the Standard timing. Motor has never run HOT in either mode. Since being a veteran Heli pilot and only doing hover/flying I knew better than to let the motor get behind the blades. I run the MS Blades. I also found that the ST with the below setup, did not really inprove my duration by more than a minute nor did it help my battery temperature, all things that prove merit to your testing.

Up to this point my setup has been the recomended high head speed 2100+ rpm guessing??, about 80% throttle and had to work out tail vibes to get a CSM LW200 to work solid. My motor has stayed really cool for the hover duration of only 7-8 minutes on a TP 1320... But the pack was warmer than I preffer about 120-130 degrees Farenheight. Thus why I too have been tinkering. I will now try the setup range you are presenting and report my results. I do not use GV mode I preffer Throttle pitch curves so to make it easy for me what is your hovering pitch angle. This will help me better find the 1500-1600 rpm range.....Thanx...........

01-24-2005 Over year old.

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turboomni
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Location: 63 Rambler Down By The Dumpster

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Well I guess the next question is has anyone flown their Shogun with a 1500-1600 headspeed? What is the head speed of the stock motor?

01-24-2005 Over year old.

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The real Ingo
Senior Heliman
Location:

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c/f: use the trick I explained. run your hely in your room until you see the blades like stopped, it is 1800 rpm.
you have my setup, with 50% throttle fixed mode you will have an hovering at 1500.
you have MS blades, me too but I have to test them better, Results are the same but the amp going up will raise less compared to stock.
I I was you I try little less than 1800 with ST.
motor wil be always cool because it has a very good self cooling it moves lot of air inside, try it without rotors you will feel the air around.
consider that y 6C li ION stay cool, no more than 40° after 15min of hovering (no canopy) they feel like a guy with fever. Im really happy for that.

Turboomni: Hovering at 1600rpm is good to me but I'm a slow guy ;-P

HugeOne: So you know relatioship between gov an rpm now you really do not need the tach! As you can see under 1800 is pretty linear....I hate to say "I knew that" Exponential is due to the joule effect that over 1800 is really consistent.
Be sure that HT and ST or LT will show different curves, the little the advance the higher rpm at max eff but less absolute efficency.
try and let me know!
What about caps to phase the motor? didi you try some tests?
Ingo

01-24-2005 Over year old.

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HugeOne
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Location: Quebec, Canada

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Did not try the cap thing yet, I'll hook up the scope to the motor first, to see what wave shape I got. To calculate the cap I must know the inductance of the coil at a certain RPM. 1800 will be a good place to start. This way maybe I'll be able to reduce the equivalent inductance to near zero so it will only leave the coil resistance and put the current in phase with voltage.

-Hugo

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The real Ingo
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You are right (as always, you are a good guy!), I mean exacly what you said.
I wait your results I'm very curious, I have DH400 not the himax so will be different.... I need the scope.
Ingo

01-24-2005 Over year old.

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e-Zoom, Shogun, Dolphin > DH400 Tech Test part 2 (stock blades)

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