ozzy9

Hi

I hava a hangar9 katana 50 powed by an Eflite power 52 ,Eflite 80 amp esc, 5 cell 18.4 lipo and a 14x8 apc prop.
While flying it has lots of power and can climb forever but 8 to 10 seconds into a hover the motor makes a screaching sound and then a total loss of power
if i throttle down and then throttle up it runs fine. this has now happend 4 times . Has anyone had this problem or know weather it is an esc or motor problem.
I have tried changing props and timing but nothing has changed. Any response will be greatly appreciated.

fmw

Almost every time what you describe is due to overpropping the system.  Something somewhere (probably the motor) is being asked to operate beyond its maximum current rating.  The times when this is not the case, the culprit is usually ESC timing.  Time to use the old reliable watt meter to check out the power system. 

chuckk2

Try a 14x7 and see if things improve.

RCMaister

I had this happen to me using a castle and the error code was that the motor and prop combo was pulling more power than the battery could provide. The castle had a setting that changed the esc from performing a hard cutoff to instead reduce the RPMS to compensate. To eliminate the problem I had to either install higher mAh batteries or reduce the prop size. Now the screeching sound is what's bothering me here. Whenever I had a motor screech, it was either timing or a problem with overloading the motor. Mostly it was a timing issue. I did have an NTM prop drive 50 - 50 from HK that would screech whenever I tried to run it on 6 Cell with a big prop. The problem went away when I ran it on 5 Cell which tells me the motor couldn't handle the RPMs and that particular prop size.

Dr Kiwi

The shutting down is a battery issue.. the pack can't cope with the excessive amp discharge and voltage under load is dropping below LVC. The proximate cause of the excessive amp discharge is a prop which is too big! The fact that the motor screeches despite your having modified the timing is an indicator of too large a prop.

You could just increase pack size (that would eliminate the LVC issue), but if you cannot find a timing advance which prevents the screech... then reducing prop size is the logical answer. I would also check the WOT amp draw, in case you are exceeding the motor's capability.

Cheers, Phil

geefish1

Hi E flyers.
Just bought an E flite Power 52 motor and put it in A Hangar 9 P 51 Red tail. Using 6s 4500mah 45c lipos. I have the same plane with e flite power 46 with 5 cells. Have not maidened the 52 yet. Anybody out there have any feedback on this new motor. Turning a 12x8 apc prop.

chuckk2

Same Model & Motor, 6S 5000Mah battery. 12x6x3 Master Airscrew prop. Electric retracts. Uses a separate BEC for electric retracts.
Weather permitting, maiden might be today.

12x8x3 is a bit much, but might work if you can restrict throttle settings until the plane is moving at speed.
A 13x6.5 two blade APCelectric prop should also be looked at (E-Calc)

How did it do with the 46 ? I used the 52 because the plane would need nose weight with the 46.

geefish1

Actually maidened it and flew it six times today. Started with an 13x8 apc prop and it was generating 1825 watts, a bit too much for the 52 which is rated at 1650 watts. Went to a 12 x8 APC and brought it down to 1575 watts. I am using a castle ice lite 100 esc with a 20 amp BEC and E Flite 60-120 retracts. It showed 118mph with a speed gun. Its a bit nose heavy but flies great. At least 15 mph faster than same plane with the e flite 46 and 5 cells, if the speed gun is accurate. It had a lot of forward momentum so I had to cut power on the base leg before final, otherwise I was overshooting the 700 foot runway. Hardly any wind today. The motor seemed to have a little looseness at the shaft. Not sure if it is a bad bearing. Will talk to Horizon Hobby tomorrow.

chuckk2

The H9 P-51 was maidened Sunday before last. It flew very well, with just slight trim needed. GPSairspeed showed 88Mph with a 12x6x3 Master Airscrew prop. Motor, battery, and ESC were cool to the touch after the flight. The P-51 easily did an extended vertical climb. No holds or frames logged during the flight.
A Castle Ice II 75A was used, and it showed a maximum wattage of 1625. A slightly rough landing was made, resulting in some gear leg bending, enough that one gear would not fully retract.
(Fixed the next day) Maximum indicated current was 68A (Static Test). Before it flies again, I'm gonna change the motor spoolup setting to the next faster setting. The landing might have been "saved" if the motor would up with less delay.
Last weekend was a bummer, due to bad weather and wind.

markskrusher

switch the timing to high!

chuckk2

Made some changes, flew the 51 several times this Sunday. Flies well, easy to control. Landings without flaps are fast!
One change was to go to a 12x8x3 prop. we also measured the overall weight, and were somewhat surprised at the results!
The listed weight (7.5Lb) was evidently with a light engine, no fuel or retracts.
This one came out at about10.5Lb in ready to fly configuration. (Just had to measure the extra electrons, heh!
Sadly HH and H9 have discontinued the model. Due to the price of spare parts, I ended up buying one on E-bay, along with a discontinued H9 P-47.
There are significant differences between the discontinued H9 P-47 and the current "razorback" version.
If it wasn't for the higher price, I'd have opted for the new version. A major difference is the use of a wing tube on the new version.

The manual claims a weight of 10-11 Lb for the P-47. Hope that is correct. If so, a Power 52 motor and a 6C LIPO should get things done. (1650W Motor)
The current ESCwBEC is a Castle 75, and the ESC's short term capability is much higher than the 75A spec.
Note: The E-Flite 80a ESCwBEC has a note about the power 60 motor and compatibility. The 52 is very similar, except for the KV rating.
With the 52, the Castle 75 ESC will cause the motor to "screech" if the motor is stopped, and the throttle rapidly advanced from 0.