Jourduson

True, I did mention it to be a (minor) problem. 😁

That's a good tip. Upon reflection the O-rings make sense. During assembly I liberally oiled them, but they are the originals. Rubber composition despite oil....? I'll try out replacing them with red ones. Thanks!

Hi everybody I have been experiencing something with some of my shocks which I have found no answer to the (minor) problem. If the car has been standing still for a while, be that an hour or weeks, two of my 11 cars have shocks that stick on first compression. Once pushed down the first time they operate flawlessly. On both cars (BBX and Optima Pro 4Wd) I've checked all parameters. Do the axels drop freely without shocks? Is the oil filling too much or too little? Is there a stabel piston rebound without the spring and are they the same? I have refilled the shocks as instructed by Tamiya and Kyosho in both cases. The BBX has TRF aeration shocks, soft springs. Both are fairly soft and react to the drop test with a nice thump and no afterswing. Does anybody have an idea what is going on? Cheers!

I just love to watch a slide-rule-using Japanese engineer in his 50ies or 60ies (Kyosho for example) build and explain the car he designed. I don't understand a word he's saying but at times subtitles pop up. For years I had a picture in mind from Accuphase amplifiers of their engineering staff. All in white smocks, slide rule and pen in their breast pocket.... These guys are so engaged in what they do and fight a constant battle with the bookkeeping and sales departments.

ad456, hi! That is a truely beautiful Scorpion you built there. I even think the bucket lights suit it well on the roof. I always felt they are too big, but here..... perfect. Did you chop the rear of the body? I'll be doing so when I build the rere Optima Pro and mount the wing instead, like you have done to give it that real vintage look. Here are some pics of my Turbo Optima/Javelin. Nope, no Kyosho driver, the drivers don't inspire me, but Tamiyas do. Yes, I do run it and crash it 😂

I have a Turbo Optima which I built up as a Javelin, an Ultima and a Tomahawk along side of a BBX, a Buggy Champ, a Fighting Buggy, a Wild One, a DT-03, and a RTR Sand Master for the Kids. All are runners. Now concerning my maintenance experience after running on dirt, gravel, sand I've found that these following three are easiest to clean and check for wear, damage and then servicing: Top of the list is the Tomahawk. Because there is no tray or protection whatsoever very little grub gets caught up. A vacuum cleaner and brush do the trick. Second the Buggy Champ, whereas I have not tried to make the box water tight, just dust tight. Third place the Fighting Buggy. All others have some sort of tray construction and collect stones and crud like dump trucks. I'm still shaking out little stones days later after the clean up and checkup/ servicing. With the Turbo Optima/Javelin I did some trial runs without the aluminium under guard and had much less to clean up afterwards, although then the lower belt box is not protected. My conclusion, the leaner and more open the chassis the easier the maintenance.

I think I've found a site that clears away the fog surrounding brushless motors and torque for me. Very nerdy in depth information without mentioning a brand or manufacturer. Some of you may already know about it, although it's mainly about planes and boats. It's homepage is: RadioControlInfo Yes, I'm a 69yo nerd who still uses a slide rule calculator with pencil and paper at times. Cheers!

Where are those independent testers. Most reviews on rc cars and accessories is pure advertisment.

True. That's why one would have to define the standard parameters of the test and test all motors the same way to make the results comparable. Just like the AES standards for measuring and testing audio equipment.

Thanks for the info. Perfect! All the important specs in one glance with the curves displayed. Note the torque/rpm curve. Define voltage, define rpm range, measure ampere across that rpm range and you would get the same kind of torque curve with a brushless motor without load. Now define a mechanical load with the same measurment procedure and then compare curves. The closer to one another the better. The 3650 looks as if it could be a hobbywing.

With brushed and brushless motors the choice is either speed (low turn no.) or power in the low rpm (high turn no) and everything in-between. So, whatever I'm building I make my choice. Two motors with the same torque but different rpm means, that the motor with the higher rpm usually is, but not in every last case, of better quality. Torque along with the efficiency in % says a lot about what is going on within the magnetic field (magnet strength, winding geometry and density, gap size). And every motor has a maximum torque, be it brushed or brushless like in the afore mentioned comment to Wooders28 with the Xerun V10. The data just has to be made public. I just wonder how many more motors than necessary have been sold because the customer bought two or more motors due to hype, insufficient or false data, until he or she had the right one for the build project.

Here is a calculation I did when a manufacturer publishes all necessary information except for torque using the link you supplied. It's not very polite to think your customers wouldn't be interested in the data.

Thanks for the information. Since I've only been using HobbyWing I knew about the the three phase rectangular puls modulation, yet they also claim that when you use a fully sensored motor/ESC system, they also include the rpm into the calculation in the algorithms.

The way I understand it, and please correct me if I'm wrong, is, given the brushless motor and the ESC are compatible, the torque is variable depending on the power requirement at any given rpm. The ESC will try to hold rpm according to the load, like going uphill for instance, by delivering more amps thus increasing the strength of the magnetic field. The result being more torque. This would explain, in my mind, the 'missing torque' with brushless motors. The same goes for the momentary battery voltage. The ESC acts as a voltage stabiliser to the motor (brushed and brushless) down to a certain voltage, so that the useful time of driving without too much loss is longer than when we had speed boxes with stepped resistors. If anybody knows more on what I've just written, he or she is very much welcome to correct and/or add to the subject.

High Kv, low turn count says nothing about the actual torque the motor is capable of.