Hobao/Scorched RC VTE Speed Build Thread

[Diem Turner]

It seems like it’s tracking very well. How are the winters there? Obviously cold when you ran it. Are you going to have to shelve it for the season? If so, that must be really frustrating after all of your work!
Also, why don’t you connect your AUX wire in the receiver?

The tracking is really good. The kind of tracking that pushes your confidence which in turn drives aggressiveness. It felt really planted and predictable, even when it spun up all four tires, I never felt like it was about to do anything unexpected. I think there's still some minor improvements to be made here and there, but I feel like the suspension setup is 90%+ where I want it to be.

As for the winters here...they can be a really mixed bag, hard to tell beforehand. Some years it will just rain incessantly from November through February and then the temperatures drop and we get intermittent snow from Feb sometimes all the way into April. Some years it will be mix of rain and snow leaving everything slushed and soggy for extended periods, always melting some away but never fully. This year the temps have definitely dropped below freezing well early compared to the last 2-3 years. I'll just have to see how it plays out and if/when it leaves me with some windows of opportunity.

I'll never shelve it. I'll always have them both ready to go so that I can be up an running within an hour or two if need be.

I set my mind on a minimalist setup with the VTE...ascetic if possible. No extra wires that aren't necessary (within reason - my cars share batteries/motors and I'm not going to cut the leads down to the absolute minimum possible, but no extra fat wherever possible. I don't see the need for a 20A BEC, 8A should do me just fine. The steering rack on the VTE is smooth and offers little in the way of resistance when compared to the Infraction. Without any kick-up induced caster, the car isn't constantly trying to force the wheels back in line with the direction of travel so there's just no need for it. Should I notice an issue at any point in the future, installing the AUX line is not big deal.

But last night definitely got me hyped to get it out for a first speed pass. It's supposed to remain dry and below freezing until Monday so, if the weather remains as advertised, I should be able to get at least a couple of passes in the next few days to establish a baseline.

 

[Moirae]

Sweet build and test pass bro. That street looked creepy AF

 

[Diem Turner]

Sweet build and test pass bro. That street looked creepy AF

Thanks my dude

IKR? When I pulled up the video on my PC I was like, "Whoa....all it's missing is the screeching radio and this is Silent Hill IRL..."

 

[Dan B.]

But last night definitely got me hyped to get it out for a first speed pass. It's supposed to remain dry and below freezing until Monday so, if the weather remains as advertised, I should be able to get at least a couple of passes in the next few days to establish a baseline.

Can’t wait to see the runs! Are you nervous going from that extra long Lim to that 330mm VTE? I’m nervous about my 325mm. Apparently they’re much more difficult and get squirrely at speed.
The photo you posted of your Lim next to your VTE really brought it home.

 

[dk10438]

Not gonna lie, it's a pretty nice servo. Don't ask me why I thought this, but I felt like it was a little underpowered for the Infraction (not that I ran into any issues with it before switching to the HRC servo) and I got this thing in my head that more torque equals better directional stability at high speeds, resistance to bump steer, etc. so I decided to go with the 44kg servo. The front kick-up automatically tries to force the wheels to point straight ahead so I wanted heading holding power.

On the VTE, the steering has far less (none?) tension in the steering geometry because it has no kick-up so it requires much less force to turn the wheels and hold them at whatever angle you have them at. As for power delivery, nothing special. I'm just running it at 6V straight off the receiver. I don't have the AUX wire from the ESC connected so I'm limited to 8A max from the BEC but I'm not getting the sense that this is in any way insufficient for this application.

The programmability of the servo (neutral position, speed, dampening and some other variables) is a nice added feature that allows me to do things like center the servo before even touching parameters like sub-trim. Is it strictly necessary? No, definitely not. Is it a nice touch that allows you to dial your steering in even closer to an imagined ideal? Yes. This servo is stupid fast and being able to tailor it to any given use case is pretty sweet. Now...is it $180 sweet? That's definitely debatable and even I'd tend to lean towards saying "probably not". But once you've rolled the price of it into an entire car...you tend to forget what you spent on it and just see the net positive of the additional features.

hey @Diem Turner
did you find SR mode to be a significant improvement? I contacted Futaba the other day and they said telemetry and SR mode were compatible with the 7PX and up? Futaba told me that SR mode was twice as fast but did not have as much "resolution". What's your opinion of this?

 

[Diem Turner]

Can’t wait to see the runs! Are you nervous going from that extra long Lim to that 330mm VTE? I’m nervous about my 325mm. Apparently they’re much more difficult and get squirrely at speed.
The photo you posted of your Lim next to your VTE really brought it home.

I was for the first while...basically until yesterday or the day before. It was so skittish my first couple of outings that I was starting to get this feeling like I was going to have to resort to electronic aides to help keep it in shape so I don't destroy it. But I kept at it and I'm glad I took my time dialing in the suspension and not going fast until the car was planted and predictable.

I just got back in from my first actual speed passes. The road was still, well not quite wet but, very moist and after the way the car drove yesterday I had no second thoughts about sending it and it went pretty much exactly as I expected. She four wheel drifts where I want her to go and even if I nail the throttle in a straight line, it stays pointed in the direction the wheels are pointed in.

So far, so good.

 

[Diem Turner]

hey @Diem Turner
did you find SR mode to be a significant improvement? I contacted Futaba the other day and they said telemetry and SR mode were compatible with the 7PX and up? Futaba told me that SR mode was twice as fast but did not have as much "resolution". What's your opinion of this?

It's my understanding, from everything that I've read, that it's not possible to run telemetry in SR mode on the 7PXR. I do, however, think you can do it on the 10PX. Since everything said it doesn't work on my Tx so I never even bothered trying. Moreover, after getting a better understanding of what they mean when they say "twice as fast" and how irrelevant it is as it relates to speed running, I still wouldn't bother, even if it were possible.

Having compared response times on my 7PXR between T-FHSS and T-FHSS SR without telemetry, I can confidently say that it makes no difference, whatsoever in speed running situations and I'll explain why that is. Before I get into it, I will say that SR and whatever the new ultra fast mode is called do have a use, but it is limited to track racing.

So when it comes to super response times, you have to look at it this way - Futaba designed these low latency transmission protocols for race drivers who are rarely more than 100ft away from their vehicle. If you're within close proximity of your vehicle, switching to the low latency protocol will cut your response times from 8ms to 4ms, or from 4ms to 2ms and I could see where, at the highest levels of competition with drivers who are fighting for tenths or hundredths of seconds might be able to benefit from steering that will allow them to dive into the apex of a turn just a little tighter, a little more precise than if their response time was double.

However, in speed running it is not uncommon to be 1000-1500ft from your vehicle and at distance I'd guesstimate that you're incurring distance latency well beyond half a second, probably more in the vicinity of 3/4 of a second. If you're even further out it might be approaching a second. There was absolutely zero difference in perceived latency at 1000ft+ out, irrespective of what protocol I was using and here's why. The SR protocol can cut the physical transmission time in half through some sort of technical wizardry. What it can't do, however, is magic its way around distance latency. So let's say that the transmitter right next to the receiver will have a latency of 2ms in SR mode vs 4ms in std. T-FHSS mode. Once you add in the 3/4 second of distance latency, T-FHSS is now operating with a perceived latency of 754ms and SR mode with a latency of 752ms.

And with that, the low latency protocols become useless when it comes to speed running and provide no benefit whatsoever. But the brain compensates for distance delay and the only time I actually still perceive it is when I'm staging the car at the starting point. When the car is standing still making it impossible to ignore how long it takes before the car starts moving when I give it a little throttle. But once I send it, the brain calibration that has taken place over dozens or hundreds of passes kicks in and it becomes almost imperceptible once the car is on the move.

That's my take on SR protocols as they relate to speed running. But, to finish the topic off, I'm really confident that average or even above average drivers simply aren't operating at a level where you or I would even notice the difference, even in a race situation simply because our reactions to what's happening on the track because our perception just doesn't have the necessary resolution to even perceive it. Kind of how visible light waves are so long relative to the size of elementary particles that it becomes impossible to make elementary particles visible to the naked eye simply because they're too small to be "painted" by the visible light wave.

 

[chris adams]

It's my understanding, from everything that I've read, that it's not possible to run telemetry in SR mode on the 7PXR. I do, however, think you can do it on the 10PX. Since everything said it doesn't work on my Tx so I never even bothered trying. Moreover, after getting a better understanding of what they mean when they say "twice as fast" and how irrelevant it is as it relates to speed running, I still wouldn't bother, even if it were possible.

Having compared response times on my 7PXR between T-FHSS and T-FHSS SR without telemetry, I can confidently say that it makes no difference, whatsoever in speed running situations and I'll explain why that is. Before I get into it, I will say that SR and whatever the new ultra fast mode is called do have a use, but it is limited to track racing.

So when it comes to super response times, you have to look at it this way - Futaba designed these low latency transmission protocols for race drivers who are rarely more than 100ft away from their vehicle. If you're within close proximity of your vehicle, switching to the low latency protocol will cut your response times from 8ms to 4ms, or from 4ms to 2ms and I could see where, at the highest levels of competition with drivers who are fighting for tenths or hundredths of seconds might be able to benefit from steering that will allow them to dive into the apex of a turn just a little tighter, a little more precise than if their response time was double.

However, in speed running it is not uncommon to be 1000-1500ft from your vehicle and at distance I'd guesstimate that you're incurring distance latency well beyond half a second, probably more in the vicinity of 3/4 of a second. If you're even further out it might be approaching a second. There was absolutely zero difference in perceived latency at 1000ft+ out, irrespective of what protocol I was using and here's why. The SR protocol can cut the physical transmission time in half through some sort of technical wizardry. What it can't do, however, is magic its way around distance latency. So let's say that the transmitter right next to the receiver will have a latency of 2ms in SR mode vs 4ms in std. T-FHSS mode. Once you add in the 3/4 second of distance latency, T-FHSS is now operating with a perceived latency of 754ms and SR mode with a latency of 752ms.

And with that, the low latency protocols become useless when it comes to speed running and provide no benefit whatsoever. But the brain compensates for distance delay and the only time I actually still perceive it is when I'm staging the car at the starting point. When the car is standing still making it impossible to ignore how long it takes before the car starts moving when I give it a little throttle. But once I send it, the brain calibration that has taken place over dozens or hundreds of passes kicks in and it becomes almost imperceptible once the car is on the move.

That's my take on SR protocols as they relate to speed running. But, to finish the topic off, I'm really confident that average or even above average drivers simply aren't operating at a level where you or I would even notice the difference, even in a race situation simply because our reactions to what's happening on the track because our perception just doesn't have the necessary resolution to even perceive it. Kind of how visible light waves are so long relative to the size of elementary particles that it becomes impossible to make elementary particles visible to the naked eye simply because they're too small to be "painted" by the visible light wave.

Your ability to express your thoughts through proper use of the English language is incredible to someone like me that "Don't talk too good"

 

[dk10438]

It's my understanding, from everything that I've read, that it's not possible to run telemetry in SR mode on the 7PXR. I do, however, think you can do it on the 10PX. Since everything said it doesn't work on my Tx so I never even bothered trying. Moreover, after getting a better understanding of what they mean when they say "twice as fast" and how irrelevant it is as it relates to speed running, I still wouldn't bother, even if it were possible.

Having compared response times on my 7PXR between T-FHSS and T-FHSS SR without telemetry, I can confidently say that it makes no difference, whatsoever in speed running situations and I'll explain why that is. Before I get into it, I will say that SR and whatever the new ultra fast mode is called do have a use, but it is limited to track racing.

So when it comes to super response times, you have to look at it this way - Futaba designed these low latency transmission protocols for race drivers who are rarely more than 100ft away from their vehicle. If you're within close proximity of your vehicle, switching to the low latency protocol will cut your response times from 8ms to 4ms, or from 4ms to 2ms and I could see where, at the highest levels of competition with drivers who are fighting for tenths or hundredths of seconds might be able to benefit from steering that will allow them to dive into the apex of a turn just a little tighter, a little more precise than if their response time was double.

However, in speed running it is not uncommon to be 1000-1500ft from your vehicle and at distance I'd guesstimate that you're incurring distance latency well beyond half a second, probably more in the vicinity of 3/4 of a second. If you're even further out it might be approaching a second. There was absolutely zero difference in perceived latency at 1000ft+ out, irrespective of what protocol I was using and here's why. The SR protocol can cut the physical transmission time in half through some sort of technical wizardry. What it can't do, however, is magic its way around distance latency. So let's say that the transmitter right next to the receiver will have a latency of 2ms in SR mode vs 4ms in std. T-FHSS mode. Once you add in the 3/4 second of distance latency, T-FHSS is now operating with a perceived latency of 754ms and SR mode with a latency of 752ms.

And with that, the low latency protocols become useless when it comes to speed running and provide no benefit whatsoever. But the brain compensates for distance delay and the only time I actually still perceive it is when I'm staging the car at the starting point. When the car is standing still making it impossible to ignore how long it takes before the car starts moving when I give it a little throttle. But once I send it, the brain calibration that has taken place over dozens or hundreds of passes kicks in and it becomes almost imperceptible once the car is on the move.

That's my take on SR protocols as they relate to speed running. But, to finish the topic off, I'm really confident that average or even above average drivers simply aren't operating at a level where you or I would even notice the difference, even in a race situation simply because our reactions to what's happening on the track because our perception just doesn't have the necessary resolution to even perceive it. Kind of how visible light waves are so long relative to the size of elementary particles that it becomes impossible to make elementary particles visible to the naked eye simply because they're too small to be "painted" by the visible light wave.

Great response!

With that being said, I do think that you are able to run the servo in SR mode with telemetry so it might be worth trying out, if you’re curious. Even if there isn’t a performance improvement, SR mode allows you to adjust servo parameters wirelessly instead of using the communication port.

I’m debating SR mode myself but this would require rewiring the car (SR not compatible with SBUS gyro connection) and resetting neutral position and endpoints.

 

[Diem Turner]

Your ability to express your thoughts through proper use of the English language is incredible to someone like me that "Don't talk too good"

I blame the drugs...and all the time I spent trying to verbalize what an acid trip looked and felt like that consisted of something more than, "...and then...it...did you see th....oh wow, that was incredible...". ;-)

 

[chris adams]

I blame the drugs...and all the time I spent trying to verbalize what an acid trip looked and felt like that consisted of something more than, "...and then...it...did you see th....oh wow, that was incredible...". ;-)

Haha I think they had the opposite effect on me.

 

[Diem Turner]

Added the Roto-Lok motor/diff mount and some battery strap buckles. The quality and mesh setting of the Roto-Lok is top notch.

 

[Dan B.]

Wow man, that’s looking awesome. Looks like you can get your packs pretty far to the front with that setup. I’ve only had experience with the PPS mounts, which I like a lot. But I wish I could see a Roto-Loc. And for 2014 technology, it’s pretty amazing.
I’ll not stop busting testicles on that time stamp, man.

 

[chris adams]

Added the Roto-Lok motor/diff mount and some battery strap buckles. The quality and mesh setting of the Roto-Lok is top notch.

In my hubble opinion, there doesn't exist a better motor mount!!! That thing looks great in your already sweet AF rig brother.

 

[Diem Turner]

Wow man, that’s looking awesome. Looks like you can get your packs pretty far to the front with that setup. I’ve only had experience with the PPS mounts, which I like a lot. But I wish I could see a Roto-Loc. And for 2014 technology, it’s pretty amazing.
I’ll not stop busting testicles on that time stamp, man.

Yeah, I'm free to position the batteries anywhere I like.
I'm a big fan of the PPS mount but this Roto-Lok is really tasty.

I wouldn't have it any other way

 

[Dan B.]

Yeah, I'm free to position the batteries anywhere I like.
I'm a big fan of the PPS mount but this Roto-Lok is really tasty.

I wouldn't have it any other way

You’re inspiring me man, I have to get back to my build! BTW, it’s good to see that 917K again. I love that thing, you nailed the livery.

 

[Diem Turner]

You’re inspiring me man, I have to get back to my build! BTW, it’s good to see that 917K again. I love that thing, you nailed the livery.

Yes...you do

 

[Dan B.]

Any problems flipping the mount on the Roto-Locs? I wonder how they would differ for clearance? When I flip the PPS I have just exactly enough space, to less than a mm, to mount a 102mm can in the forward position. So I guess the question is, are those mounts any thicker than the PPS? Because if they were it would be a no go for mine.

 

[Diem Turner]

Any problems flipping the mount on the Roto-Locs? I wonder how they would differ for clearance? When I flip the PPS I have just exactly enough space, to less than a mm, to mount a 102mm can in the forward position. So I guess the question is, are those mounts any thicker than the PPS? Because if they were it would be a no go for mine.

They're no thicker than a PPS. If anything, they might actually be a smidge thinner.

 

[Dan B.]

They're no thicker than a PPS. If anything, they might actually be a smidge thinner.

Hmmmm…. I could actually use another motor mount. The PPS could replace an EXB mount on my (pretty much stock) Typhon basher.

They're no thicker than a PPS. If anything, they might actually be a smidge thinner.

I saw this on the Scorched description…
PLEASE NOTE! Due to the extra width of the mount, an extra 1.5mm of room is needed for the motor compared to the stock mount.
I really can’t spare 1.5mm in length. Is he talking longitudinal or diagonal here?