Limitless Can someone explain trigger control?

[dure16]

I’ve seen proper trigger control mentioned but I’m trying to understand exactly what that means for speed running.

I know the timing of throttle delivery can impact current and heat build up but don’t understand the right strategy to use, or what signs to look for in a data log.

Any help is appreciated!

 

[LibertyMKiii]

I’ve seen proper trigger control mentioned but I’m trying to understand exactly what that means for speed running.

I know the timing of throttle delivery can impact current and heat build up but don’t understand the right strategy to use, or what signs to look for in a data log.

Any help is appreciated!

As you mentioned it is all about controlling the amperage levels. As the amperage goes up your voltage will go down. This means less RPMs and ultimately less top speed.

As you are looking at your castle data logs you will find that it is the final 25% of the throttle pull that hurts the most because this is when the load is the greatest.

There is a fine balance between getting the pull slow enough to help reduce the amperage loads and having enough time to get the car up to speed in the amount of road you have to use and can see with your eyes.

For example a 10 second throttle pull would probably be great but you would need over 1/2 mile to use that at peak speeds over 150mph.

I have found a something around 5-8 seconds is ideal, but varies based on how fast you are going. A 2 cell run going 100mph can use the 8 second throttle pull, but a 8s run over 150 mph needs something a little shorter. The sweet spot for me seemed to be in the 7 sec range.

This is a 124 mph pass on 3s with the VTE2 using the FC100 body. If you follow the green line you will see it is very linear up till the ESC makes full power (the light blue line). This being so linear is because I was utilizing the throttle control from the Noble NB4 radio. After I reached full power the amperage loads started to come back down. This appears to be a 4.2 second throttle pull but it was a rolling start so it was probably more like 5 seconds. Had I extended this to 7 seconds I could reduce that amperage load quite a bit and would have been a few MPH faster. In general I have found it is good to get up to speed quickly in that first 0-50% of the throttle range and then slow it down in the 2nd half of the throttle pull.

 

[Dan B.]

As you mentioned it is all about controlling the amperage levels. As the amperage goes up your voltage will go down. This means less RPMs and ultimately less top speed.

As you are looking at your castle data logs you will find that it is the final 25% of the throttle pull that hurts the most because this is when the load is the greatest.

There is a fine balance between getting the pull slow enough to help reduce the amperage loads and having enough time to get the car up to speed in the distance you have to use.

For example a 10 second throttle pull would probably be great but you would need over 1/2 mile to use that.

I have found a something around 5-8 seconds is ideal, but varies based on how fast you are going. A 2 cell run going 100mph can use the 8 second throttle pull, but a 8s run over 150 mph needs something a little shorter. The sweet spot for me seemed to be in the 7 sec range.

This is a 124 mph pass on 3s with the VTE2 using the FC100 body. If you follow the green line you will see it is very linear up till the ESC makes full power (the light blue line). This being so linear is because I was utilizing the throttle control from the Noble NB4 radio. After I reached full power the amperage loads started to come back down. This appears to be a 4.2 second throttle pull but it was a rolling start so it was probably more like 5 seconds. Had I extended this to 7 seconds I could reduce that amperage load quite a bit and would have been a few MPH faster. In general I have found it is good to get up to speed quickly in that first 0-50% of the throttle range and then slow it down in the 2nd half of the throttle pull.

View attachment 356762

That’s a great explanation and very useful information.

 

[LibertyMKiii]

This log was 135mph on 3s and was over geared. Normally I should see the amperage (Green line) start to go down after hitting max power output (circled in red).
Because the load was too high with being geared too high the amperage continued to climb.

I had a prior run at 135 with conservative gearing and it ran much cooler and much lower amps.

2 easy indicators to see here beyond the lines of the graph.... 666 amps and the ESC temps were very high. The ESC shut itself down, which is the vertical Red bar at the end of the run. This left the car sitting in the middle of the highway. This is why James McCoy in his recent video he talked about using an RX battery pack so you can steer the car off the road.

Once you get to the point of being over geared all you are doing is over heating your motor and ESC.
You will hear people say to gear up slowly and "follow the process". You have to make little changes and analyze the data. Making big jumps up in gearing cab result in bad situations like this one. I think this was a 3 or 4 tooth jump on the pinion. I knew better, but had limited time to run the car and did something I regretted quickly.

 

[LibertyMKiii]

The other thing to remember is the motor, ESC, and battery is working a complete system.
You can move to another LiPo and have a completely different graph curve because of a better performing LiPo.

Suddenly when the motor looked like it was maxed out you have another 5-10 mph. (example going from CNHL G+ 70c packs to Onyx or SMC top tier batteries.)
Because the more powerful batteries maintain a higher voltage under high amperage loads they will turn more rpms. Gearing down may be the answer which blows some peoples minds. Less gear to go faster

I say all of this to say if you make a significant upgrade. Gear down and work your way back up to get the best results.

 

[dure16]

@LibertyMKiii - damn. You answered my questions plus all the questions I didn’t know to ask. The time spent at full throttle, the current decline after peak power, and the caution with gearing jumps are all great advice. I really appreciate it!

 

[Jerold]

Trigger control is pulling the trigger and firing the gun without disturbing the point of aim.

.... Oh, we are talking RC cars. What they said. I have a bad habit of pinning the throttle when it passes me and I get the ramp (current spike) to go with it. <- not trigger control.

 

[LibertyMKiii]

@LibertyMKiii - damn. You answered my questions plus all the questions I didn’t know to ask. The time spent at full throttle, the current decline after peak power, and the caution with gearing jumps are all great advice. I really appreciate it!

Happy to help!
Feel free to shoot me a private message once you make your first runs and pull the data logs. We can go over them and help you understand the data.

 

[Micron]

Trigger control is pulling the trigger and firing the gun without disturbing the point of aim.

.... Oh, we are talking RC cars. What they said. I have a bad habit of pinning the throttle when it passes me and I get the ramp (current spike) to go with it. <- not trigger control.

I found that I was doing the same when the car passes bye me also. lol

 

[LibertyMKiii]

I found that I was doing the same when the car passes bye me also. lol

Very normal.
You are thinking I need to get to 100% and then end of my road is coming up soon. Before you know it you just jumped the throttle from 50% to 100% all at once.

One of 2 scenarios happens next.
1. Wheel spin and potential crash
2. Amp spike and you ruined the run

Either way the run gets ruined. It's soooo much harder than it looks to speed run.
It is a highly technical segment of the hobby.

 

[Micron]

Very normal.
You are thinking I need to get to 100% and then end of my road is coming up soon. Before you know it you just jumped the throttle from 50% to 100% all at once.

One of 2 scenarios happens next.
1. Wheel spin and potential crash
2. Amp spike and you ruined the run

Either way the run gets ruined. It's soooo much harder than it looks to speed run.
It is a highly technical segment of the hobby.

Yep yep! I started speed running this time last year with a Rlaarlo AK917 and man I learned trigger control the hard way! Your "Scenario 1" with a massive crash! I pulled full trigger as it went past me it instantly sheared the left rear dog bone pins then started burning all three tires and turned left into a curb almost head-on at 135mph! I did the exact same thing the day before, but I saved it by missing the curb by an inch or so. You think I might learn from it right? Not yet! lol, I repaired the dog bone and went out the next day and I did the same thing AGAIN and well it was mostly wasted!
I need to post the video of that pass at some point to possibly help someone out!
Anyway, great info boys! Thank you

 

[Jerold]

Yep yep! I started speed running this time last year with a Rlaarlo AK917 and man I learned trigger control the hard way! Your "Scenario 1" with a massive crash! I pulled full trigger as it went past me it instantly sheared the left rear dog bone pins then started burning all three tires and turned left into a curb almost head-on at 135mph! I did the exact same thing the day before, but I saved it by missing the curb by an inch or so. You think I might learn from it right? Not yet! lol, I repaired the dog bone and went out the next day and I did the same thing AGAIN and well it was mostly wasted!
I need to post the video of that pass at some point to possibly help someone out!
Anyway, great info boys! Thank you

At least you made it to 135, I didn't even break 100 with that one. Kept looping it, short wheel base and lots of juice a tough combo. It needs a bit of work, but I will try to run it a few more times before it goes on the block.

 

[Dan B.]

Trigger control is pulling the trigger and firing the gun without disturbing the point of aim.

Nope. You squeeze the trigger, you don’t pull it. And when speaking of long arms, only a shotgun is a gun. “This is your rifle, this is your gun. This one’s for shooting, this one’s for fun.” Old Marine Corp adage. You must be Army…
Just kidding, man. The only reason I replied is because my dad has told me that so many times it’s ingrained in my brain!

 

[aaronass]

Awesome info here Liberty. Mods should pin this for future help

 

[dure16]

Awesome info here Liberty. Mods should pin this for future help

That’s a great idea. @slick2500

 

[Jerold]

“This is your rifle, this is your gun. This one’s for shooting, this one’s for fun.” Old Marine Corp adage. You must be Army…

https://www.arrmaforum.com/threads/signs-you-might-be-an-rc-addict.65490/page-4#post-999093