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Ok I missed a few posts I guess lol
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Totally understandable. I tend to put a lot of details in there, mostly for me and about 1% of the people actually care about. Then there is the other 1% that just look at the pictures. For the rest of the 98% it's crap shoot if it's read or not.Ok I missed a few posts I guess lol
I think you have the gain turned up way too high. I'd try recalibrating and then turn the gain down to 15-30% and see how she does.Gryo Jitter?
I'm not sure what this is and maybe someone can help me. Maybe I'm wasting my time?
In the last installment my Gryo phase was backwards. I would turn right, it detected a right side skid and corrected by turning right. It's interesting but not very useful.
I pulled out my RadioLink manual and it says to change the phase.
View attachment 249632
As soon as I did that and the front wheel just shook while sitting on the bench. It stopped when I picked it up. The phase is correct. Back moves right and it steers right. As soon as I drove it down the drive way the front wheels started wobbling.
This first video is just me moving the wheel. The first 10 sec have the Gryo on at ~80%. Note that it's not responsive and very chunky. It's almost like the sample rate (assuming it's digital) is too low. The next few seconds is after I turned the Gryo down. Notice the servo is nice and smooth now.
The second video of the car driving and you can see the front wheels "hunting".
Any thoughts are helpful.
Too much gain makes sense but it didn't occur to me that too much gain was an option.I think you have the gain turned up way too high. I'd try recalibrating and then turn the gain down to 15-30% and see how she does.
When you turn the gain up to high it starts reacting to everything. You can tell when the gain is turned up too high when the car starts oscillating.Too much gain makes sense but it didn't occur to me that too much gain was an option.
Recalibrate the Gyro? I believe it calibrates/initializes when the power is turned on. I just need to make sure it's level and not moving.
Fall Colors and an PB
I finally got out to do some more runs.
The short story is I got a new PB of 113 MPH on 8S with a D/R set at 90%. More importantly NO CRASHES! Yah!! But I did get some audible codes from the ESC.
It's only +2MPH, I'm trying to take baby steps until I figure out what's what.
View attachment 256163
Leaf Collection
When I lived on the east coast and when the weather turned, so did the leaves. You could count on piles and piles of leaves, with bright orange, yellow and red colors. There is nothing like the fall colors on the east coast. I guessing my Limitless feels the same way because it brought me a present. No it's not staged, it collected the leaves and kept them through a 100mph run.
View attachment 256130
Car Setup
Arrma Limitless OG (aka not V2). Changes are in bold
Stock Body8S - (CNHL 9500 4S) X 2Servo Relocation Mod/ RX relocationStock D-Boots and GRPsBEC Voltage 7.0VThrottle D/R 50-90%Steering D/R 50%Gryo enabled @0%The servo relocation works well for this application. I wouldn't use it for bashing, racing or crawling, but here it's fine.
View attachment 256156
I didn't see any rubbing or binding; although, I need to go through the car and will update if I find anything. The mounting surface is the front down brace and it is a bit flexy under load; however, I shouldn't "need" to make any quick turns. I'm hoping the solve the flex problem with an aluminum brace, the question is will my center drive shafts clear? I have the Raz Shifrin CF drive shafts and they are amazing, but also a bit stout so I had to clearance the factory plastic braces... which doesn't help the brace with lateral force. Please let me know if you have any ideas which front aluminum braces work with RS CF drive shafts.
Using the Throttle and Steering Dual Rate is very useful. The throttle is good for a few warm up passes where I can practice the throttle control without the speed. The steering really helps me keep it going straight. I will definitely being adding this as part of my regular setup.
I did enable the Gryo, but found it to be a bit too much. When I was testing it I noticed a wobble from too much gain, which limited me to something like 15%. However, when I got to my spot I tried it out and even at 30MPH, 15% was too much. So I dialed it back to a big-old 0%. Maybe it's because I increased the BEC voltage to 7V and the servo is more responsive. Which makes the control loop is smaller and needs less gain?
Practice Time
A while back is was short a battery and limited to 4S only and pretty much maxed out at 75MPH. I actually learned something from the limitation, there is a lot more to this than a fast car and pinning the throttle. There is some skill and experience to driving a 15lb car at 100,110. 120...MPH. Being limited on speed allowed me to just drive the car and not worry about going fast.
Basically I learned it's important to get more low speed passes. This time I started with 8S but turned down the Throttle D/R to 50% and started working my way up. Just like last time the speed was ~75MPH. Back down the D/R and made more passes. Eventually swapped to the GRP tires and had 2 passes at 100+. There was probably a 3rd but my GPS wasn't on - Doh!
ESC Codes
I managed to get this to happen twice. I made a run then staged for another one. The car cut slightly at first acceleration and then continued then continued to perform as expected. The code sounds like "o - - " which would be Excessive Load.
I'm not sure what the load would be, it was very easy acceleration from about 2 mph? The video is below.
Data Log
My log is attached in the ZIP file.
I'm still going through them, but I can immediately see a few things. the first is I had much more time at or near 100% throttle (relative to the D/R setting). The last run I had over 2 Secs of full throttle. The acceleration is looking much less jagged.
This is my last 113MPH run. You can see a plateau for the throttle followed by the braking. The throttle ramp is a bit exponential; however, I also figured out that if I get it rolling and straightened out, then give it the beans, I can get to get max speed in less space.
View attachment 256171
Another thing is the Voltage droop and Watts. My Watts went way up, like to 11K and my Voltage Droop was very high and dropped to 23V. That seems a bit much to me - Comments?
View attachment 256173
Carnage got the best of my Front wing. Same as yours, stripped. Shoogoo worked for a brief while. But then I just used a 3 mm oversized screw.Front Wing Screw Mod
I ran into a minor problem right after I got the Limitless roller. The front wing wasn't very well attached and would pop off with just about anything. It turns out hole for the screw had been stripped out. The wing, with screw attached went flying up in the air. This was temporally fixed by adding a bit of electrical tape on the screw to take up some extra space but that didn't last long.
Eventually I replaced the front bumper (ARA320515) and that fixed it for a little bit until the screw pulled through the Lexan wing. Which left me front wingless.
View attachment 226989
Not wanting to spend $30 on wings, I was thinking to add a washer on the top. However, looking through my stash of stuff found a set of 1/8" Hillman screw covers #881025.
This not only fixed the problem but makes it look more finished too.
View attachment 226990
Don't tell Hillman though, because the get rebranded to Arrama Screw Covers and cost $8.95.
Yup that makes sense. I'm asking it to do more work when it's working the hardest. But is 11KW excessive? I mean it's only like eight toasters.Other than finding the perfect road, the next hardest thing is getting the throttle pull just right. That is the cause for you amperage spike here. You will need to attempt to get on the throttle really aggressively initially and then slow it down towards the end.
I have drawn over your screen shot the black chisel line is about what your throttle line was.
The Red is more of what I would like to see you do instead:
View attachment 256178
I saw your Hobao @127. It's impressive. Pointers, yes please. My goal is 130, given my space constraints I think it's a reasonable goal and running 4S or less is considerably less stress on my wallet, my car and my brain.Another thing @Jerold is that driving on 8s is very hard.
Most of us found learning this side of the hobby is considerably better on 3s and 4s.
I was able to reach 127 mph on parallel 3s packs and now shooting for 150 as a goal for parallel 4s. Might be worth trying 4s for a bit. Happy to coach you on it if you would like some pointers.
Yup that makes sense. I'm asking it to do more work when it's working the hardest. But is 11KW excessive? I mean it's only like eight toasters.
I saw your Hobao @127. It's impressive. Pointers, yes please. My goal is 130, given my space constraints I think it's a reasonable goal and running 4S or less is considerably less stress on my wallet, my car and my brain.
Maybe someday I will find a better road with less liability to it.
FWIW, 130mph on 4S is well with the realm of possibility. You don't need 8S for that. That just increases the likelihood of accidents. I just got back from a 4S pass and set a new PB at 131mph.Yup that makes sense. I'm asking it to do more work when it's working the hardest. But is 11KW excessive? I mean it's only like eight toasters.
I saw your Hobao @127. It's impressive. Pointers, yes please. My goal is 130, given my space constraints I think it's a reasonable goal and running 4S or less is considerably less stress on my wallet, my car and my brain.
Maybe someday I will find a better road with less liability to it.
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