Limitless Talbot's fastest RC car project discussion

[LibertyMKiii]

@LibertyMKiii has a decent thread here. We can reverse engineer what KT did on his Lim. and offer why it will or wont work on a technical level. That's how many can learn here. Lets not hijack this thread with nonsense.
This thread should remain on a technical level. Like KT or not is your own opinion. We should accept those comments here, not be insulted if you don't agree, and move on.
I feel KT did not consider much when choosing motor placement and didn't select the correct KV or consider that a direct drive to the F/R diffs eliminated much if any gear reduction options. KT just slammed it with electrics impulsively. Much of KT's stuff is impulsively motivated. I don't see much planning or technical explanations of what he did. Because he has nothing to back them up. Just slam it with $$$. $$$ he has to play with these toys. Much are wasteful attempts. Most of his content is like that. Not realistic for the average Speed Runner or Rc'er in general. The weight of that rig exceeds the parameters of any tires in this scale. This project is out of his league so to speak.
But from a business standpoint will pay his bills whether successful at 203MPH or not.
He chose the wrong Radio set for this project. He is in over his head on this one. He gets help from many other seasoned RC builders when he is stuck. He is not a one man band with great experience. Just appears that way. He is an RC jack of all trades master of none. He just wants you to keep coming back for more. Lets keep it in perspective.

I agree,

The purpose of the thread was to look at what KT was doing and poke fun a little.... But was never meant to be a why we hate KT thread or why I like KT thread. It was about the pursuit of top speed and why he may or may not get there.
So far I am impressed with how far he has gotten and in the RC speed world MGM ESCs are mostly unknown so I had wondered how they will work out for him.

I think overall the setup could work, but I would want the motors coupled in the middle so that the front and rear tires don't spin different RPMs.

Another point is that it has been well proven that one 56mm motor is plenty to reach 190mph with a Limitless so he has only added extra mass to the setup that is un-necessary.

 

[Johnnytoofast]

I couldn't have said it better myself. Why get so bent out of shape over something that doesn't pertain to you. If it's not your cup of tea then don't drink it.
Everyone needs to take a deep breath calm down and go fast. Get out there and have some fun and stop worrying about what someone else calls fun.

 

[Exc3l]

I think overall the setup could work, but I would want the motors coupled in the middle so that the front and rear tires don't spin different RPMs.

This is exactly what I was thinking too. I have seen Raz Shiffrin use a dual-motor mount. Did he make or buy that?

 

[Johnnytoofast]

And yet no one is talking crap about raz and his two motor setup.

This is exactly what I was thinking too. I have seen Raz Shiffrin use a dual-motor mount. Did he make or buy that?

And his two

 

[ABabyEater]

I couldn't have said it better myself. Why get so bent out of shape over something that doesn't pertain to you. If it's not your cup of tea then don't drink it.
Everyone needs to take a deep breath calm down and go fast. Get out there and have some fun and stop worrying about what someone else calls fun.

Conversely, people need to get over themselves if someone express displeasure over something.

Arbitrary example: I don't like the instability of the Notorious. I am allowed to express that I don't like the Notorious in a thread about them without people jumping down my throat about it. If all I say is "I don't like the Notorious" it isn't constructive, but rather than people getting offended by it, better they ask why I think that. Discussion comes from two sides.

And yet no one is talking crap about raz and his two motor setup.

That is because iirc at the time he was actually going into more unknown territory rather than refusing to learn from what is common knowledge among anyone with any experience in speedrunning.

 

[LibertyMKiii]

This is exactly what I was thinking too. I have seen Raz Shiffrin use a dual-motor mount. Did he make or buy that?

You can buy it on eBay. Both motors drive the original center spur gear. (one motor has to turn in reverse) Keeps everything like stock basically....

 

[Jimbobjr]

Wow, 12 pages of this...

 

[jkflow]

Wow, 12 pages of this...

Yes, you discovered the business secret behind most Youtube channels, it's called controversy.

 

[Notorious J]

Conversely, people need to get over themselves if someone express displeasure over something.

Arbitrary example: I don't like the instability of the Notorious. I am allowed to express that I don't like the Notorious in a thread about them without people jumping down my throat about it. If all I say is "I don't like the Notorious" it isn't constructive, but rather than people getting offended by it, better they ask why I think that. Discussion comes from two sides.

I am Notorious and I approve this message

 

[SrC]

Now getting back on topic, I feel like KTs arrogance and blatant hypocrisy will keep him from getting anywhere close to his goal of 200+, but it will absolutely get him his goal of views and income. He is an entertainer with RC as a backdrop, and like it or not, there are enough people that are entertained by him to not only make it successful for him, but to maintain his success.

Well said. RC is his backdrop/ world stage. RC is his tool for success. He just found a way to reach many and keep them coming back for more of whatever they feel is entertaining. Not all of us are in that catagory however.

And yet no one is talking crap about raz and his two motor setup.

And his two

Raz is not a hack by any stretch of the imagination.
Far from it.

 

[Mr.Duke]

Conversely, people need to get over themselves if someone express displeasure over something.

Arbitrary example: I don't like the instability of the Notorious. I am allowed to express that I don't like the Notorious in a thread about them without people jumping down my throat about it. If all I say is "I don't like the Notorious" it isn't constructive, but rather than people getting offended by it, better they ask why I think that. Discussion comes from two sides.



That is because iirc at the time he was actually going into more unknown territory rather than refusing to learn from what is common knowledge among anyone with any experience in speedrunning.

You don’t like the Notorious?
How can this be…..Are you cray-cray?

Take it back and agree wiff me or muh feelz gone break bro.


j/k

 

[SrC]

You can buy it on eBay. Both motors drive the original center spur gear. (one motor has to turn in reverse) Keeps everything like stock basically....

You are essentially doubling your torque with a dual motor mount. And one must consider the extreme weight that results. And Double the $$$. Perhaps double the fun. Depends on your $$$: Fun ratio.

 

[Johnnytoofast]

I honestly don't think youll go faster. Maybe more torque but I don't know with all the weight and all that.

 

[SrC]

A super torquey and "efficient" (90%+) single motor setup is where I would want to be at. Think $Handwound$.

 

[LibertyMKiii]

You are essentially doubling your torque with a dual motor mount. And one must consider the extreme weight that results. And Double the $$$. Perhaps double the fun. Depends on your $$$: Fun ratio.

Right and more power in most cases will generate more speed, but that increase is small when at the crossing lines of the graphic noted below. And you are attacking the problem with the wrong solution.

It is the case of what looks cool and is easiest to do. Making a custom body gets out of peoples comfort zones. It is easier to slap electronics in the existing platform.

I take this approach:
1. What is stopping the car from going faster?
1.1 Aerodynamic drag
1.2 Friction and mechanical issues

There is a point where throwing more power at a problem nets little to no difference.
This is an example from airplanes, which due to the aerodynamics is very relevant. It is also worth noting that you can only put down so much power with these foam tires before they slip or blow up.

The correct solution would be to get a car dialed in functioning as the best of the best in the 170-190 mph range.
Then improve the aerodynamics enough to reduce the drag stopping it from reaching 200.

This was my hope for Raz. I wanted him to take his known 170 mph setup and just swap the body. Instead he went down the "how can I get more viewers" path.

There are 3 key needs in reducing the drag.
1. Smoothing and controlling airflow. (could also get into ground effect, drag, vortex creation, and other sub topics.)
2. Total height and total width that make up the aerodynamic frontal area.

My original speed car build utilized the Senton 6s arms and axles to reduce the width of the car. It also didn't have suspension which allowed the body to fit very snug just above the height of the differential. I wish the new owner would have tested its abilities, but I had the same feelings about it. It is too pretty to drive and risk the crash.

 

[SrC]

Dialing in Negative pressure Ground effect can compensate for some Positive pressure body Aero issues.
If aero stability can be achieved, then higher Torque will get you there. Weight at those higher speeds is overcome at the top end. It's getting to the speed threshold where weight can be an issue. Amp draw etc.
I think I follow you ??

 

[LibertyMKiii]

Dialing in Negative pressure Ground effect can compensate for some Positive pressure body Aero issues.
If aero stability can be achieved, then higher Torque will get you there. Weight at those higher speeds is overcome at the top end. It's getting to the speed threshold where weight can be an issue. Amp draw etc.
I think I follow you ??

Talking with James McCoy (who is now at 190 mph with his GT Limitless)
Advised that adding weight really hurts the time to get to full speed and the braking distances.

One of our other obstacles is the roads we have available and distances we can see/control the car in.

Torque is best at pushing through the aerodynamic drag, and there is a formula that shows how increasing speed by power alone requires this insane increase in power because that values is cubed. Approaching the problem from aerodynamic drag reduction is the best path in my humble opinion. This takes the value that your are applying the cube function to and reducing it. This will drastically reduce the power required curve line!

Aerodynamic Drag – The Physics Hypertextbook

"Drag is proportional to the square of speed, then the power needed to overcome that drag is proportional to the cube of speed (P ∝ v3). You want to ride your bicycle twice as fast, you'll have to be eight times more powerful."

Example if your RC car took 2.5 hp to reach 90 mph it will take 20 hp to reach 180 mph.

Also revised the airplane graphic to match what we are seeing today with the 1/7 scale cars and power output required.

View attachment 165823

 

[rotauq]

Thinking out of the box, my mind wandered into warp bubbles and how teleporting would be cheating...
Changing the air density in front of the car, maybe go on the highest possible mountain plateau. Conventional engines don't like the thin air, but aero does

 

[LibertyMKiii]

Thinking out of the box, my mind wandered into warp bubbles and how teleporting would be cheating...
Changing the air density in front of the car, maybe go on the highest possible mountain plateau. Conventional engines don't like the thin air, but aero does

I have had no luck with teleporting so far...

Yes running in high elevation will help and works great for electric motors vs combustion engines.
Also warm temps makes for thinner air. Notice both the 190 mph records were set in July/August?

Colorado springs is within a 1 day drive for me and is around 6.3k feet elevation (aprox 1000' higher elevation than Denver)
They have some smooth roads too!

 

[jondilly1974]

I have had no luck with teleporting so far...

Yes running in high elevation will help and works great for electric motors vs combustion engines.
Also warm temps makes for thinner air. Notice both the 190 mph records were set in July/August?

Colorado springs is within a 1 day drive for me and is around 6.3k feet elevation (aprox 1000' higher elevation than Denver)
They have some smooth roads too!

My son used to live in the Springs when he was an intern at the Olympics. I don’t remember seeing many good quality flat roads there, but I’ve only visited for a few days a few times. There are ENDLESS crawling and bashing spots there though.

Oh and I think the most of the Springs is 7000ft and above. An hour drive up to Pikes gets you above 14,000ft.