my 3dx500

[Heli Joe]

Thanks a lot for the info. I will try that in my next flight. I think that it would be ok with my pinion because in hard flights the headspeed seams to be a little bit too low. So that should be also better now. And also the ESC and motor temperature should be lower than..

I will tell when i have tried it...

Greetings from Austria

Joe

[Rudy C]

Hi Joe, we Love Austria! Wife and I went there for two weeks on our 30th wedding anniversary. Lived in the Alps in Erhwald. We visited Salzburg, home of Mozart, the king. Every moment of this vacation was unforgettable. You are so fortunate to be in one of the most beautiful places on earth. On another note, as in previous threads I own an HDX 500. My only problem with it is slow cyclic. Please let me know what you think. Rudy C.

[Heli Joe]

Hi Rudy !!

Thanks a lot...for Salzburg - what a coincidence that you where allready here ... I also live not very long here. I am here since a half a year. But it is nice... Really. But there are also a lot of other really nice places on the world.. My dream is Canada ( East or West coast ). Thats also great.

So, now to your question about the HDX. How long - how much flights - to you have with it. I had it also at the first time but it is getting better now. Maybe the belt is not running very good in the first time and then you get a cyclic. but normaly then up and down. The other thing could be a too slow mainrotor speed or a slow tail servo. ( Is the linkage or the tail servo working smoothly ???). I have to give a very low sensibility on my gyro. Then it was working good in hoovering.
Is the cyclic only at hoovering or also in straight flight ???

Cheers from Austria

Joe

[Rudy C]

Hi Joe, I think u misunderstood my last thread. I was talking about how fast the heli responds in cyclic inputs. (very slow roll rate) Heli Direct.com says they are comming out with longer cyclic levers to overcome this problem. i'm afraid to try any wild stuff with it until I get this sorted out. No issues with the belt, tail or any of that stuff. I use the 68cf tail blades, and made my own tail fin out of G10 material on the scroll saw. How.s the weather in Salzburg? Good for helis I hope... BTW, this HDX500 is very stable in hover and plenty powerful with 4cells and the wonderful German motor Kontronic Kora 15-12..I was playing with mine today, the weather was HOT! but the little 500 stayed cool! Good luck>>>>>>>>>>>>>>>>>>>>>>>>>>>>

[Heli Joe]

Hi Rudy !!

Yes that was a missunderstanding. Sorry but some spezial words i still have some problems. But it would be easier from time to time.
Yes - that is right. Did you trie some smaller lighter paddles ??? I did it and then it is much better. On pix are still the original ones.
But i still have another problem. ( the weather is also a little bit hot here in Salzburg and sometimes a little bit windy ) and at high temperatures i have the problem that the motor is getting really hot. And then the power is goiing down and down.
I am not sure, but i want to stay at the 3 Lipo version.( Still have some 3S 4000 Lipos ).My motor has a 990 rpm/min/Volt and in case of the 3 Lipos i gave him a 26 T pionion. Because if i take a smaller one ( 24T ) then the headspeed ( calculated ) is much less then then it should be. But otherwise maybe in the praxis the motor has more power with the smaller pinion and then it is running better and is getting not so hot.
You have the Kora 15/12 with 4 Lipo. So if i try the Kora ( Is for sure the better motor ) i think i have to take the 15/10 with more rpm and a smaller pinion that i go better with 3S Lipo.
What to you think ???

Cheers from Salzburg

Joe

[kgfly]

Joe the low gearing ratio caused by the 94t main put a high load on the motor.


Sample eHeli gear ratios
========================

------------- ---- ------ -----
Heli Main Pinion Ratio
------------- ---- ------ -----
T450 150 13 11.5
EP8 120 20 6.0
Lepton/HDX500 94 23 4.1
T600 170 11 15.5
------------- ---- ------ -----


You can see how the design of the Lepton/HDX500 really makes the motor work very hard with such a low gear ratio. You might be interested to know that Steve of HeliDirect is experimenting with a new 150t main gear. It would make a big difference to the gear ratios. For example for a 3s setup you could use a Hacker A30-XL 1100kv and even with the same 23t pinion that you are know running your ratio would be 6.5, a huge improvement on the 4.1 you have now. With say Z20-1700kv you could choose a range of pinions from around 19t to 24t. A comft crusing setup on 20t would be a 7.5 gear ratio which should greatly reduce current draw and hence heating, giving improved efficiency, less bogging and longer flights.

I don't know yet if the 150t gear will make it through from experiment to production but it is an interesting possibility.

[Heli Joe]

Hi Kenneth !!

Thanks for you explanation. You are right. From this side I still haven't seen it. That I can get a good ratio i must use a 14 T pinion that I come on a ratio of 6,7...
Then I have to use a Motor with about 1700 rpm/V that i can range a good headspeed.

Thats maybe a better solution.

Thanks from Austria

Joe

[kgfly]

Two problems we face. The first is finding suitable >500W range motors with 5mm shafts and the right KV that will fit the frame. The second is the limited range of 5mm/module 0.6 pinions that are available. RevCo makes a range of suitable (Lepton) pinions from 18t to 23t: http://revco-rc.com/index.php?cPath=21_24&osCsid=d87614d20530667d3bfa1b5e28100d68.

So working backwards to get the best gear ratio we choose the smallest available pinion, which is 18t pinion. Now we can consider what KV motor would be required.

LiPo per cell voltage
=====================
Max 4.2
Nominal 3.7
Loaded 3.5
Min 3.3


Heli parameters
===============
Heli Model HDX500
Main gear teeth 94
Pinion teeth 18
Efficiency 95%
LiPo 3S (11.1V)


Headspeed estimates (rpm)
=========================

Motor KV Max Nominal Loaded Min Example
-------- ---- ------- ------ ---- --------------
890 2000 1800 1700 1600 HDX500
980 2200 2000 1900 1800
-------- ---- ------- ------ ---- --------------
1100 2500 2200 2100 2000 A30-8XL
1130 2600 2300 2200 2000 AXI 2826/8
-------- ---- ------- ------ ---- --------------
1250 2900 2500 2400 2200 ?
-------- ---- ------- ------ ---- --------------
1360 3100 2700 2600 2400 Typhoon 600-33
1470 3400 3000 2800 2700 Z20-1500
-------- ---- ------- ------ ---- --------------
1700 3900 3400 3200 3100 Z20-1500
-------- ---- ------- ------ ---- --------------

If the above analysis is even close to being right then I think 1700kv would be too high with an 18t pinion. Around 1100kv looks nice for learner/mild sport flying and around 1500kv for 3D. Since you cannot go below 18t but you can go above, it would seem a flexible combination could be a ~1100kv motor like the Hacker A30-8XL with an 18t for getting started and 19t/20t for more aggressive flying as skills progress. This would have the motor operating at ratios in the range 5.2 to 4.7, still somewhat better than the ~4.0 with the stock motor and 23t/24t pinions.

[BobOD]

with 4cells and the wonderful German motor Kontronic Kora 15-12..I was playing with mine today, the weather was HOT! but the little 500 stayed cool! Good luck>>>>>>>>>>>>>>>>>>>>>>>>>>>>

I'm quite confused by this. From what I can find of that motor, I wouldn't think it would have nearly the power to handle an 1800g heli. If it did, at only 150 grams, I'd buy it right away.

Rudy, what head speed do you get and with what gearing? How many amps?

[Heli Joe]

Hi Rudy !!

Another question about the Head and Tail Grip direction.

Is that correct like on my picture ?? In the construction manual there is the Main Rotor Grip linkage in the front of the blade ( when you look in rotation direction. ). Mine are on the backside of the blade. The HDX is flying perfect with that solution... ????
Or does it make no differenze.???

Thanks Joe

[houstonrevo]

kgfly,

I have a Hacker 30-8xl sitting around and 18T pinion. Based on you calc but with 4S, would I be better off with the hacker 8 turn that than my current set up (hyperion 3025-10 and 23 T pinion) for more torque and power?

I think I can gain about 27% more torque due to the gearing change from 23T to 18T but the 8 turn motor has inherently less torque than 10 turn motor so i don't know if I am gaining anything.

[Rudy C]

Joe head looks right! If tail was not on correctly, it would spin out of control and u could not fly it.

[Rudy C]

Hi Ken, Thanks for the info on gear ratio's ect. It makes sense to use a larger tooth main gear, and a truly hope HeliDirect does this. This is a good heli, but it IS heavier than the Hirobo Lepton. Maybe by as much as 10-12oz. I use the Kora motor because the junk motor the heli came with got way to hot! The Kora gets hot but nothing like the original motor did.

[Rudy C]

I'm quite confused by this. From what I can find of that motor, I wouldn't think it would have nearly the power to handle an 1800g heli. If it did, at only 150 grams, I'd buy it right away.

Rudy, what head speed do you get and with what gearing? How many amps?

Hi ya Bob, The kora Rocks! I use Max Amps 4000 4s packs, 24tooth revco pinion medium timing on the stock hobby wing ESC and turn a 3000Head Speed for about the first 3 min of flight. With lite 3d expect a 6 min flight. Don't take my word for it, talk to John at Ready Heli.com and ask him about this particular motor. Every item I own from Kontronic, has never failed me and I love it........................

[kgfly]

kgfly,

I have a Hacker 30-8xl sitting around and 18T pinion. Based on you calc but with 4S, would I be better off with the hacker 8 turn that than my current set up (hyperion 3025-10 and 23 T pinion) for more torque and power?

I think I can gain about 27% more torque due to the gearing change from 23T to 18T but the 8 turn motor has inherently less torque than 10 turn motor so i don't know if I am gaining anything.

It is hard to know based on theory alone.


Heli parameters LiPo per cell voltage
=============== =====================
Heli Model HDX500 Max 4.2
Main gear teeth 94 Nominal 3.7
Efficiency 95% Loaded 3.5
LiPo 4S (14.8V) Min 3.3


Headspeed estimates (rpm)
=========================

Motor KV Pinion Ratio Max Nominal Loaded Min Example
-------- ------ ----- ---- ------- ------ ---- --------
890 23 4.1 3500 3100 2900 2700 HDX500
-------- ------ ----- ---- ------- ------ ---- --------
1100 18 5.2 3400 3000 2800 2600 A30-8XL
-------- ------ ----- ---- ------- ------ ---- --------


Clearly running the Hacker A30-8XL on 4S/18t should give you similar headspeed to the HDX500/23t (which is no suprise since 23 x 890 / 1100 = 18.6) but with so many variables invovled it is hard to know whether it really is more efficient and less likely to bog. Empirical testing is the way forward ;)

It would be great if you could log a flight with the HDX500/23t combo and then log one with the A30-8XL/18t combo and let us all know how it works out :)

[houstonrevo]

I emailed Hacker. From what I was told, apples to apples, running a hacker A30-10xl with 23T or running a hacker A30-8xl with 18T on 4S, the 8 turn has slightly higher power (about 5%).

However, I have a hyperion 10 turn so I don't know how it would work out. I guess I can tried both and see. The problem is that it is such a pain to swap out motor with the lepton.

[kgfly]

...the problem is that it is such a pain to swap out motor with the lepton.
Easy fix, get a new HDX500 to wrap around that Hacker motor ;)

[Heli Joe]

Hi Kenneth !!

I will try now in the next weeks a new Motor from MVVS ( I am not sure if you know that company but they have a lot of very good gas Motors ). Thats a new outrunner with van.
You can take a look at this in my attachment or directly on the webpage mvvs.cz. Looks good and there will be the interresting one 3,5/1400 Sport.
We will se what happens with this motor.

Cheers Joe

[Heli Joe]

Hi Kenneth once more.

Here a 2 more datasheets from the MVVS Motors.

Cheers Joe

[kgfly]

Hi Joe,

Thank you for the info. What a coincidence! A friend of mine is currently testing an MVVS motor (4.6/1120) in his new HDX500. See here: http://www.rcgroups.com/forums/showthread.php?t=720533

I got another fly in today. I started at 2100HS and the heli is a little ***** cat. Not quite authorative enough for my likes but i was at 40% throttle. I stepped things up 10% at a time to get into a happy place. By the time i was up to 2400 the heli felt much better to me and i was surprised at how good it felt at the lower speeds.

I have setteled on 2540ish for the time being. The heli sounds very happy and response is more than adequate for me. I suppose the closer to 3000 it gets the more brain power i will need but that can wait until i get some more flights on it.

So far the mvvs is doing vey well and the Jazz does what a Jazz does (works bloody well).
The logictec 6100 is also impressing. After the effort to get the 2100 dialed in i was not looking forward to doing the 6100 but it has just fallen into place.

These flights have been running the 4s A123 cells (to lazy to check any of my other packs and during testing its nice to not worry abou over discharge).

This build started with great impressions as i begun and has continued to impress right thru.

Mind you, those MVVS are very expensive :shock:

[houstonrevo]

Easy fix, get a new HDX500 to wrap around that Hacker motor ;)

I may end up with a HDX500 if (when) my lepton crash into pieces and replacement parts cost as much as the HDX :)

[Wirestealth]

Hi any one with the stock motor and stock controler?

This are my settings and motor run HOT very Hot!
brake-----------------Off
battery type--------Lipo
Cut Off Type-------Middle
Star mode----------Soft
Timming Mode----High
Governor Mode----Off


Belt tension is ok every thing very smooth

Nuno from portugal

[Heli Joe]

Hi Rudy !!
Hope you are fine and the wheater is good. In Salzburg it is raining and so i have a lot of time to think about a new motor for my HDX 500.
We had about 20 degrees temperature in the last days and the motor was gooing hot like in the other days. I think it is gooing hotter and hotter every flight. Also now with the 24T pinion. It is running still on his limits. So before it is burning and i crash in case of that i will change it to another one.
I am thinking about a Kora 15. I am still not sure if i should take a 15/10 or a 15/12 for 3S Lipo use.
I will get a theoretical headspeed of 3037 rpm ( with Kora 15/10 ) and 2547 rpm ( with Kora 15/12 ). I think in case of that the 15/10 is better but the 15/12 has more power i think so. ??? What should i do ???

What do you think about that ???

Cheers from Salzburg

Joe

[petmen]

take the kora 15-10 i love it on 4s its a gun.

[BobOD]

take the kora 15-10 i love it on 4s its a gun.

I still have my doubts about this Kora. I don't think I could buy a motor from a manufacturer that doesn't even list the continuous/surge current rating. Can't find it anywhere. At 150g weight, being the lightest motor being used on this heli, it just seems too good to be true.

Petmen, what are your running conditions? How hot does it get? How many flights do you have on it?