MVVS 6.5/910 and EMax BL2820/07 performance

[kiwibrit]

Are the performances of the MVVS 6.5/910 and EMax BL2820/07 broadly equal for use in a stunt model?  I've been recommended a MVVS for a project, and  appreciate the excellent build quality. However, in the UK the MVVS is four times the price of the EMax motor. 

[Russell Bond]

There is a saying and it goes; " Buy cheap, buy twice." And it is so true.

The Emax is an Arrowind and they are very "average" in quality. Go for the MVVS.

[Keith Renecle]

Hi, The MVVS 6,5/910 is a classy motor.......like Russell says, but it is a bigger and more powerful motor than the E-Max/Arrowind 2820/07. This E-Max is a good .40 equivalent, and the MVVS will fly a .60 size model. I have used plenty of E-Max 2820's and they are a very good motor for their price. I have also sold plenty of them as well and had zero comebacks. The bigger 2826 motor is similar to the MVVS 6,5/910. I have both of these motors and the MVVS is a superior motor in all ways, but then you must compare apples with apples. The cheap bearings in the E-Max can be replaced but they last quite long anyway. The 2826 motors do have magnets that come loose if they get too hot, but you can glue them back. They are good sport motors and not recommended for serious competition. Right now, it looks like a good value for money motor  is  the Cobra,  and they have a big range to choose from. They have good bearings and a larger than normal one at the rear of the motor. They have also added a retaining ring at the rear of the magnets so it looks like they have done their homework.

RSM Distribution also has some nice Black Tiger motors that are work looking at. They have good quality bearings and better than average magnets. I have a few of them myself and so far they are doing very well. Another medium price motor range that is also good is Scorpion, so you have a choice. MVVS does not have a .40 size motor that is the equivalent of that E-Max 2820. They have their in-out runner range but they are more suited to gliders and are quite heavy for their size. The 6,5 designation is supposed to be a .40 size glow equivalent but not in C/L terms. This is something like the E-Flite Power 15, 25 or 32 range. The Power 15 is the same as the E-Max 2820. The E-Flite motors are another option for you to look at.

Will Moore said some years ago that you can basically choose the right motor for your model by the motor weight and Kv rating. A good thumb-suck is to estimate the overall weight of the model and divide that by 10 to get the weight of the motor. Then you can decide on the number of cells in the battery. For a .40 size plane that will weigh around 1200 to 1300 grams (around 50 oz. max) you can use a motor that weighs around 140 grams, and 3 or a 4-cell pack. The higher the voltage, the lower the current, and with a 900 Kv, like that E-Max, this will work with a 4-cell lipo of 2200 mAh to a little higher depending on the weight of the model. Have fun, and if you need any more help, then this forum is the place to ask questions!

Keith R

[Igor Burger]

The cheap bearings in the E-Max can be replaced but they last quite long anyway. The 2826 motors do have magnets that come loose if they get too hot, but you can glue them back. They are good sport motors and not recommended for serious competition.

I fully agree, beside that word "good" :- ))) if loosing magnets or bad bearings are "normal" troubles, then you pay money for troubles. Remember, those motors are designed for light R/C flight, berings are simply undersized for C/L pattern and also we fly them at all time power, unlike R/C gus playing with throttle. I tried several motor types including chep Chinese, I can say that "overbuilt" = "expensive" European motors like MVVS, AXI or Plettenberg are OK (some little better in quality, some better in design etc, but all well usefull) I never had success with cheap motors, I had even problem with Scorpions which are counted to be "those better" simply those cheap motors are designed to be on edge all ways, so simply something MUST fail sooner or later. There is only one reason to use such motor, and that is if beginner expects crashes. So if someone learns pattern then it does not make sense to buy expensive Plettenberg.

Will Moore said some years ago that you can basically choose the right motor for your model by the motor weight and Kv rating.

Wasn't it me with Allan Hahn?  ... in Any case yes, that motor over is much smaller (powerwise) then MVVS 6.5. But I think Also MVVS 6.5 is still not equivalent of 10ccm engine, Czech guys (beside Jiry - he went back to AXI) fly MVVS 8 in 10ccm models, it is little bit overkill, but I think better then undersized. AXI 2826 is smaller then MVVS 8 and I would like to have something little larger, unfortunately AXI does not make little larger motor then AXI 2826 and they did not want to make motor little longer as I tried to push them, that would be my dream motor :- )) ... so far I solve it with heat sink ... I feel it will be necessary for ECh in Bulgaria this year :-P

[kiwibrit]

There is a saying and it goes; " Buy cheap, buy twice." And it is so true.

The Emax is an Arrowind and they are very "average" in quality. Go for the MVVS.

The thing is the EMax is more than twice as cheap. So there is a case for choosing one, and having a spare motor in the flight box.  

At the moment, I am still in the beginner category, really, despite my age. I have had problems coping with the sun, and consequently crashing models.  I seem to be coping better with that now, but I'm not confident that I'll have no more trouble. Equally, I tend to fly my manoeuvres too high, but when I bring them lower I sometimes misjudge pull outs. The most recent example when I pulled out too low from an outside loop was quite spectacular - the fin ripped off the tail plane, and the rest of the model bounced and flew on a further 1/3 of a lap. The Renecle governor did its job, and the motor was stopped on the first bounce. The only damge to the motor was a bent mounting plate.  

Now this sort of thing does not happen every day. I fully expect to bring my models back and hang them up after a good day's fun. But the chance of something going wrong makes me wonder if I should fork out for a MVVS when an EMax will do. I'm aiming to start competing in British Class 2 comps in the coming season, and the project is for a 58" stunter, so I may splash out. Decisions decisions.

Anyway, some interesting answers, and food for thought as I progress. Many thanks.

[Keith Renecle]

I fully agree, beside that word "good" :- ))) if loosing magnets or bad bearings are "normal" troubles, then you pay money for troubles. Remember, those motors are designed for light R/C flight, berings are simply undersized for C/L pattern and also we fly them at all time power, unlike R/C gus playing with throttle. I tried several motor types including chep Chinese, I can say that "overbuilt" = "expensive" European motors like MVVS, AXI or Plettenberg are OK (some little better in quality, some better in design etc, but all well usefull) I never had success with cheap motors, I had even problem with Scorpions which are counted to be "those better" simply those cheap motors are designed to be on edge all ways, so simply something MUST fail sooner or later. There is only one reason to use such motor, and that is if beginner expects crashes. So if someone learns pattern then it does not make sense to buy expensive Plettenberg.

Wasn't it me with Allan Hahn?  ... in Any case yes, that motor over is much smaller (powerwise) then MVVS 6.5. But I think Also MVVS 6.5 is still not equivalent of 10ccm engine, Czech guys (beside Jiry - he went back to AXI) fly MVVS 8 in 10ccm models, it is little bit overkill, but I think better then undersized. AXI 2826 is smaller then MVVS 8 and I would like to have something little larger, unfortunately AXI does not make little larger motor then AXI 2826 and they did not want to make motor little longer as I tried to push them, that would be my dream motor :- )) ... so far I solve it with heat sink ... I feel it will be necessary for ECh in Bulgaria this year :-P

Igor, I read it first in an old Stunt News article before this forum got going, but for sure I do sometimes talk to you as well( ) so maybe it could have been you. I just feel that in the case of sport flying or beginner stunt, then the Chinese motors like E-Max work fine. I have been flying my 1850 gram Electron for a long time with the MVVS 6,5/910 with one of those extra wide 12 x 6 props from Dennis, and it handles it very well. O.k. so let's call it a .49 to .55 size engine equivalent. I also don't fly 100's of lights per month so maybe that is why I get away with the Chinese stuff. I still believe that for the .40 size models, that particular E-Max is very good value for money.

Keith R