Hi  am having a strange problem with a D2826 Turnigy motor  my setup is 2826Motor  On 40amp Esc with a 7X4 prop. The motor starts making a tapping sound at about 80watts (reading on my watt meter)  the same motor is okay with a 6 X 4 prop.  The battery am using is 2200mah 11.1 v   ....

Past the 80 watt it accelerates and WOT is around 340 watts  (7X4, 7X4.5  2 & 3 Blade)   the 6X4  prop delivers 180 watts at WOT.

I want to use this on 850 gm AUW model hence was trying higher trust.

Any diagnostic tips would be greatly appreciated.

Thanks
  

If you do that again , definitely you are going to burn your motor!
for 2200kv motor 7x4 prop is more over load for 3 cell (11.1v)
as specification says 7x4 is used only when 2 cell is used (7.4v)
Best suited is 5x5 or 6x4 !

@ nakul here refer this link : https://docs.google.com/spreadsheet/ccc?key=0AtSZzrsraF1-dDJzNGVEMnZnRzNzMkJab2dfRjlxMnc&usp=sharing

prop data for d2826-6

might as well refer this vdo

Try another 7*4 prop. This one might be imbalanced. I use a 9*47 without problems

In most of the cases 6*4 prop works fine with high kv motors and always a better option.
7*4 may seems as over load on your motor.

6x3 prop is best for this motor if running from a 3S battery. It probably gives the best power consumption to performance ratio for this motor. All Up Weight should be ~1000-1200g for this motor-prop combination for a hand launch.

Max current consumption should be ~13-16 Amps. So max power consumption should in the 140-190W range.

As Praveen said, DONT use 7x4 prop with motor when using a 3S battery. You are very lucky the motor hasn't burned yet.

Hope this helps... 

 as all have suggested, please use 6x3 or 6x4 propwith the 2826- 2200kv, 7 inch is fine for the 1500kv version, less current draw with latter. 850 gms sky surfer will fly but 850 gms propjet will have difficulties.

Prop - motor - battery assembly is the touchy thing that creates the best or worst performance overall.
As battery and motor's are too costly than prop, so prop is always used for final tuning.
And it is better to use higher dia and lower pitch prop for slow fly. But as this is a medium KV motor, you should not use prop dia more than recommended except pitch compensation (keeping dia² x pitch = constant).

My apologies: I saw this on a mobile phone, and read 2826, not 2836. You will have to prop down, 6*4 or 5*4

I saw a youtube video where a guy used a 7*3 prop producing 1200gms. Thrust.

for 6x4 prop factor = 6x6x4 = 144 and for 7x3 prop factor = 147 and for 7x4 prop, factor comes = 196.
So you cannot go beyond 70% (144/196) throttle with 7x4 prop.

Hi guys,

Thanks a lot for those tips  will do the needful and research some... I was rely on Utube thrust test and Motocalc which indicated 7X4 was ok   anyways motor is fine  and 6X4 for todays test flight.  Thanks again

Nakul

Hi   a clarification the motor is a D2826 though all of you seem to have caught my error.   Thanks

ps:have corrected Title error

@nakul
My 2826 2200kv broke the prop at the hub on opening the throttle. Not once but twice with 7035 props. Then used a Sharma 7x4, that gave lot of thrust but also a lot of left banking torque. Motor got hot. Then used an old Cox 6x3. This solved the torque problem, and allowed the motor to rev. Now on APC style 6x3.

Moral:
Don't use GWS type thin props, use APC style, 6x3 is enough. The prop tip will be doing about 700 kmph!

@Nakul. Plz correct the title of this topic. 

Hi everyone..in conclusion the D2826 was not able to cope with 840gms AUW..  the plane F35 depron  with mid back pusher config it just spun and had damage to the nose so its back on the work table Maybe a re-build and will restrict AUW to below 700gms and see what happens.  Really appreciate all the inputs I recieved  Thank you all..

Try using a 2500kv motor