Hi Gary, Why the special interest for 1630 grams? Yes the T-Motor props are the V2 versions, they look very promising but the V1 where also looking promising but we know how that wend Mario
Ok, Best is to look at the lifting forge you need, for example 1000 grams that equals a AUW 8Kg octo Mario
Mario agree but other than comparing lift/force from the same motor and current how would you compare one prop over another, at least from a data standpoint? Other measurements like vibration and sound seem to me more subjective. I was picking 10amps since that is a bit higher than what I see on 4s, which in of itself isn't much of a data point Thanks for doing the testing. Only suggestion would be to keep the motor consistent. I noticed that the earlier tests used a different motor. And at least in the states I haven't heard of many folks using the Plettenbergs.
Gary, Well at first they need to track well and they must be reasonable in balance when they come out of the box, if not they are not worth looking at. An other important point is weight, you don't see that on the testing results but we all know that less weight brings more stability in flight because of the quicker response to the throttle input from the gyro's when there is less mass to move, so although most time the bigger the propeller the better the efficiency but there is a limit if your gain is smooth video results, for me the limit is 13">14" for propellers with a weight of 25 grams and more, and 15">16" for propellers with a weight of 25 grams or less. Indeed I use a lower KV motor now for testing because of the bigger propellers but its from the same series so the results are the same, only the end power is lower and you need more throttle input for the same outcome. Mario
Mario, thanks for all the testing... appreciate it since it can't be cheap. What props/setup do you recommend on a X8 coaxial? I'm running Xoar 14x6 top and bottom now. I'm wanting to gain some efficiency back so thinking of moving to a larger carbon props. Issues is what... without spending a fortune on testing size and pitch. This is what I came up with from eCal on 400kw motor. Option 1 = 16x4 top and 15x4 bottom Option 2 = 15x5 top and 15x6 bottom Option 3 = 15x6 top and 14x6 bottom
Jason, I have no experience with coaxial setups, but I think you will gain efficiency and stability if you change the Xoar 14x6 for the Mejzlik 15x5 top and bottom, or maybe the Mejzlik 15x5 on top and the Mejzlik 16x5,5/6 bottom. Btw, there are also extra light versions of the Mejzlik propellers but they cost more. Mario
Thanks for your input Mario. How are you liking the build quality and balance of Mejzlik vs the Tigers?
Jason, Balance is good for both brands. The build quality of the T-Motor V1 propellers are top notch, wish that there performance where on the same level Mejzlik quality is a bit less but there performance is the best I ever tested. Mario
Just arrived, 10 pieces Mejzlik 15x5 (light version) for real flight testing on the Kratos. Weight 12,41 > 14,51 grams
How is the size difference from an Xoar? They look very similar in profile. I want you prop collection
From top to bottom, Mejzlik 15x5-L 12.41 grams / 378mm long Mejzlik 15x5 18.71 grams / 378mm long Xoar 15x4 29.04 grams / 380mm long Xoar 15x6 30.50 grams / 380mm long
Mario along the line of the earlier test it was interesting to see that at 10 amps x 2 motors the coax was delivering about 2800g thrust vs the 1600 delivered with single motor/prop. Which seems to support the anecdotal evidence that Coax are 10-15% less efficient.
Hi Gary, Yes I know coaxial isn't our choice because of the lost efficiency and a very quick popping up of a motor in your picture, but there are guys that love coaxial setups because of the extra stability gain, but IMHO you get the same stability gain if you change your propellers for two sizes smaller without popping up motors in your picture Mario
Mario it is a great test series. This is the first time I have seen some empirical testing with results that clearly show the efficiency loss. Nice job!
Thanks for the pics and coax test! Would you mind trying two coax tests (with xoars since they have different prop pitch): 1) same size prop top/bottom but higher pitch prop on bottom 2) 1 inch smaller prop on the bottom of the coax. Theory is the bottom should rotate faster to cut into the turbulence from the top prop. Yeah the coax will loose about 1 minutes flight per but 6 minutes per battery set up is more than enough to get the shot. We have 12 parallel sets and a dual 70amp charger so we can keep up all day. I swear by coax since every time I have done a shoot, its 5+ knots wind... where before the Hex would float on the wind with the large surface area like a leaf... where now it just charges right though it, I have had many people on set eve comment about it without me even stating it I knew the props where light but didn't realize it would be 140gr/0.3lbs. Doesn't sound like a lot but this + changing out other things could drop enough weight to get some efficiency back with a coax The props look pretty much like the Xoar, I wonder if the tiger's wider spoon design with lower pitch would help with coax's or hinder? I'm doing prop test next week and will report actual flight times. 14x6 top/bottom, 15x5 top/14x6 bottom, 15x5 top/bottom and 16x4 if I can ever find them!
Jason, I don't see the point for going coaxial, see the shoot we have done with a Kratos and a CS3 servo mount, we are now working on a brushless mount that can handle even more wind. Shoot of the Mazda Imax-5 Guinness World Record 2013 with a total of 683 Mazda MX-5 sports cars in a parade. 17.9-24.0 (Gusts 36) mph!! Mario