Hi,
i have been working on a HK450 since the past 2 months but cannot get the bird to fly.

Here is my setup
Brushless outrunner motor - 3500KV
ESC - 25A hobbycity fried, Now using 35A

The ESC runs very hot ( cannot touch) , the top cover of ESC is already split due to excessive heat.
Head speed is low and the tail wags right on throttle increase.

I suspect the power in the bird is very less but i have checked everything for binding. Even fixed the lower belt gear lateral movement not heard of this issue.

My assumptions for this problem
1. There is a high vibration in the heli during spool up at low speed, but it reduces with high speed.
- Blades : I balanced again both individually
- Tracking no issue
- Main shaft , Checked by Amit Kumar.
2. Motor or ESC is bad, How much should be current(A) on a hovering heli

So i dont know if i should buy carbon blades or change the Motor / ESC combo.

Any Advise will be most appreciated.

There are lots of small issues (individually or together) that can cause this. Listing some that comes to my mind, will add more later. Obviously there are bigger factors, like the motor itself being bad or the battery being bad etc.

1.  The pinion gear on the motor shaft is rubbing too closely with the main gear. In other words, the motor is pushing against the main gear. You should fold a piece of paper in two, and insert that between the pinion gear and the main gear, push the motor towards the main gear, tighten it, and then rotate the main gear to remove the piece of paper (you should get a zig zag wrinkled piece of paper, leaving the "right amount" of gap between the main gear and pinion gear).

2.  I am not sure if the HK450 comes with multiple pinions like the Trex 450, where there are 11teeth, 13 teeth etc.  The higher the number of teeth, the higher the headspeed, and load on the power system.  Please confirm how many teeth are on the pinion gear (which is on the motor shaft).

3.  Check your tail belt tension.

4.  Too low head speed (as determined by a low throttle curve) is not good, so check your throttle curve.

5.  Make sure moving parts are moving free, lubricate them if needed.

6.  Guess you have verified the battery is fine, by trying alternates.

When you do not have enough headspeed, the tail kicking is an obvious result.

thanks for your reply anwar ji

1. Pinion pressing - Done
2. Motor ESC - Changed
3. Pinion changed from 13T to 11T
4. Lubrication - Done
5. Belt - Checked

Still i have already burned 2 ESC and the new one is from Mystery and trips on getting heated up.

I have been suggested to change to 9T by Amit kumar, but as per me 11T pinion cannot be the reason of heating up.

So i would appreciate help from All.

As per [2], both the motor and ESC have been chaged, or just the ESC ?

Remember that going down on the pinion is in many ways equivalent to running on a lower throttle curve. 

The big question is, are you having enough power/rpm to lift off ?  Have you verified that you have a proper pitch curve ? Since you have someone experienced helping you, I hope they have looked into these aspects.

At this point, I am tempted to ask for a video of you trying to spool up and fly this heli. How are you defining "low power" ?

dear anwar ji,

Lift off is not a problem, but i am burning on ESC current at all head speed, be it lower or higher.

Tried everything

I will post video at end of this week.

Big question unanswered, have you changed both the ESC and the motor, or just the ESC ?

If you keep the heli on the ground with the blades spinning at say 30% to 40% throttle (for say 3 to 5minutes), does the ESC still get overheated and cut-off ?

anwar ji,

yes, changed both motor and esc

I tried with 40% throttle for 2min but no heating

Then it is probably a head speed thing.  Try lowering the pinion further, or adjusting the throttle curve.

If you have a pitch gauge, can you measure and post your actual blade pitch at 0%, 25%, 50%, 75% and 100% throttle stick positions ?  Please post also corresponding throttle curve values.

Hi,

Also what battery are u using with the setup as make sure that the C's are calibrated with the ESC and motor type


Thanks
Hellyflyer