Sorry for this question but Im not sure Im following. Are you saying that by bringing the roll center closer to COG we will retain more of our static camber under higher corner loads?
great video.. would you have any dyno runs for the stock 540 as well as tamiya torque and sport tuned motors .. id like to compare them to the GT tuned.. the only info i can find is max rpm (which as you showed is meaningless)
The biggest issue will be scaling the values calculated by the program. Since a CrossKart is a full scale vehicle this may be an issue. I suggest you install the program from the website and try it out. There is a 30 day free trial period
That must be the best video on RU-vid. Everybody repeats what he read elsewhere, but you are really going beyond that and pushing your analysis. Awesome work and explanations! Thank you RCCrewChief
j'adore cette vidéo, elle donne une bonne dimension de la corrélation des différents réglages d'un châssis, ainsi qu'une bonne base dans la mise au point d'un set up. Merci
Thank you im new to club racing and I'm trying to figure out what all the adjustments actually do and this explanation helped me to understand how to adjust and what for glad I found your content very informative
gosh I hate to be that guy. I dont point this out to take anything away from your work. I have allot of respect for it. You take the general methods rc people use to tune their motor and put science behind it. its very ahead of its time. if most guys took it half as far as you it would be amazing. But here is the rub. permanent magnet motors are not used in applications that are horsepower driven applications. Yet all our motors are. for HP application you want max torque at average rpm not 1 rpm. applying a PMDC motor can be done by using HP and its usually a 3rd or 4th priority when maximizing it in an application. sizing for HP is something that is done primarily when running at a constant rpm or acceleration and deceleration are not important. PMDC motors are sized for an application by the discrete accel/decel rates of each segment of the motion profile.
i suspect the knees that you see are from the incremental boost being added catching up with the ideal trigger point. being ahead a couple degrees of ideal finally reaching ideal and giving it a minor bump in power. The crossovers ive seen are normally a fixed point based on the constants in hp power calculation but i didnt think hard on that. as it relates to maximizing a motor in an application you have two degrees of freedom or restriction. peak power or peak efficiency. an auto commutation program calculated the trigger point for both efficiency and power so that when the motor is in use it only blends between those two limitations. if you do dyno runs that you are trickling in the right amount of timing offset for every discrete rpm you can use this to create a table that an rc guy can use to set his timing. so if you have a track 1000 ft long and you want to run it in 10 seconds you can calculate the average rpm to do this. you set the blinks timing to this 1 end bell setting and you will have max power for that motor on that track. if you then did a series of tests that allowed you to calculate the exact amount of heat that the motor could dissipate continuously and in a 5 minute period you could use a thermal time constant to limit the amount of power (a different average rpm) that is above peak efficiency but below peak power. this is fundamentally what a servo drive does in field oriented control continuously but because an industrial servo is updating the thermal model in real time it can adjust peak power and peak efficiency timing (commutation) on the fly. its also predictable with a thermal time constant. what this means is you can have a published power curve that is limited by heat and as long as all the calculated points on the curve average below the continuous portion of the curve you can have peaks that are above the average 100% duty cycle portion of the curve.
I can take a stab at some things that you might be seeing from one esc to the next. commutation is an output. its the relationship of when the coil is fired. the more precisely it is triggered in the real world the better it will be. there is a frequency at which it triggers. the processor has a fixed frequency and the transistor has a fixed frequency. if both are at a very high frequency there is more resolution to the physical relationship of the rotor and coil. the same concepts apply to the sensors that are being read. you have hall effect sensors and sensor less measurements based on back emf. In general, the error or accuracy of the last coil firing hinders or helps the next pulse a 5% change in output is probably common.
Great video!!!, please teach us about Chassis Dyno for 1/10th Nitro IC, and how to analys the data provided by MiniPRO and from RCCrewChief. Thanks for all
Can't really help you with Nitro as I don't have race that class so no motors to test. You can create a Nitro motor model in RC3 once you have a Torque versus RPM dyno data. This video has some info on Nitro motor modelling studio.ru-vid.comEczz4hxJBb8/edit
Not to my knowledge. There is lots of info out there on Ackerman angles but since this is a dynamic property the only way I know of is to calculate the inside/outside wheel steering angles for any position is to use the actual geometry.
Hello, Very nice video! How do you go about adjusting roll center, camber gain, etc. using a Pillowball style frontend? Do you offer Arrma 1/7 Car or 1/8 Buggy models in your library? Cheers
Adjustability needs to be built into the suspension to allow for roll center and camber adjustments. For pillowball suspension you would need to be able to adjust the position of the inner pivot point of the lower/upper control arm. I do not have models for the chassis you mentioned but you can create your own models by accurately measuring the suspension geometry. There are videos on the website that go through this process. The program has a 30 day trial period if you want to give it a try.
The 748e has a 200mm track width which will introduce slight errors in the camber, toe and steering throw measurements. A custom steering throw adapter would be needed to interface with the front shock tower. As the S411 is a 190mm chassis it will work fine.
RC Crew Chief seems to be a very useful program. I have watched a few of your videos, I think even for those who are good at chassis setup, there could be a benefit of running the program. The animation feature for a setup change looks useful.
@@RCCrewChief I'm not actually racing right now, but I plan to race again in the near future. Once I am competing again, I may give the software a try. Thanks.
Does it matter a lot if suspension arms are gullwing style? I just bought the software and measured a B74. The rear arms are not straight, but are angled upwards behind the shock mount, so the angle of the arm shown in the software does not match the angle of the real arm.
No it does not. The arm length is still the distance between the inner and outer hinge pins. The reason the arm is gull wing shape is to lower the shock mounting points which helps to lower the CG and/or increase the shock stroke in bump. The lower shock mount position will account for the gull wing shape.
@@RCCrewChief Thank you very much for your reply. Maybe you can help me out with two more questions regarding the measurement of my B74. This specific har has seperate mounting points for king pin and camber link on the front hub with the ball for the camber link on the inside and steering arm mount and king pin locatet on the outside. I suppose that the resulting model has more king pin inclination than the real car. Does this matter for the calculations or can i ignore this? As the front drive shafts are inclined backwards, what would be the better representation for Axle Cl, through the diff, which gives a longer Lcc or through the CVA axle, which gives a shorter Lcc?
@@shunryusuzuki6285 The King Pin and steering axis are are different on the front. The program can handle this. The King Pin length will be measured between the arm outer hinge pin and the camber link ball stud. Those are the suspension pivot points. For the steering you should measure Lcc to the Axle CL
Edited:: after watching battery video I think I need a better battery.... :) Hello, your video was very very informative and this is the first one I've watched but I will definitely be subscribing and watching others. I see that there is no different between the 120amp and 200amp esc comparison. I'm curious on your opinion for using an 80amp esc over a 120amp esc for blinky mode? Do you think there would be a huge difference in motor performance with those amperage esc? I'm just getting into this and I'm currently using the budget turnigy trackstar combo 17.5 and seem to lack power when going for longer jumps. Turnigy trackstar 17.5 combo 80amp esc, 4600mah 100c battery, 72spur/30pinion. In order for me to make the biggest jump for indoor carpet track I have the bell timing turned to the max degree. Motor comes off the track at 140-150 degrees
You may get better results turning down the timing as high timing settings are good for maxing out top speed on long straights. What you sacrifice to achieve that is bottom end torque which translates to less acceleration. Also there is no substitute for good batteries. The ESC comparison is for full throttle operation. At part throttle results would likely be different.
Appreciate this advice I will definitely be turning down the end bell timing and getting better batteries!! I will test this out next time at the track. Thanks
I have watched many of your videos, and found them very helpful. I am asking your opinion on a current project. I am working with a light 1s pan car, and I am after top speed only. Insane run type situation. I am currently using a 4.5 motor. Do you think I should use motor timing only? Motor timing with boost and turbo, or just one? Should I shoot for a total target timing setting?? Thanks
