Kraton ROCKET BOOST KRATON 6S AND 8S

[arelee]

One of the reasons that I decided to get back into RC cars, after 37 years, was because I watched the David Windestal youtube video, "Recreating the Mythbusters rocket car (with a RC car)". However, he ran a 1/10 scale, Hobby King "Desert Fox". I wanted to go bigger.

I bought a Kraton 6s and an 8s. After getting the low down on how to properly use LiPo batteries, from some great people on "Arrma Forum", I am ready to learn what it will take to run the car(s) at top speed, then engage a model rocket, that will be built into/ onto the car(s), starting with the Kraton 6s.

Currently, aside from swapping out the the stock bearings with sealed bearings, the car is stock. I'll start by upgrading the motor, ESC, pinion gear and tires. What would be the best combination of these parts, to get the highest top end speed? Next is the rocket mounting system and location.

I am new to model rockets. From what I've read, size "G" engines are the largest that can be used without having a level 1 certification. Anybody know anything about model rockets? From what I've read, an Aerotech, G54W-14A White Lightning is VERY high thrust, and, no HAZMAT charge= normally $35.00, (I think).

The rocket motor mounting location and platform are crucial. I have some ideas, but any suggestions would be great. This is going to be fun!

 

[jondilly1974]

I’m not a fan of doing rockets, but there is a guy on YT already doing it

 

[Notorious J]

Mounting a rocket?. Since you plan on running it on flat surfaces, I don't think any extra bracing is needed, but you might consider raising the dif fluids, especially in the center. 500k or 1M to keep the balance from front to back. Changing just the pinion isn't the only thing to consider. You might want to change the center spur as well. Gearing this beast properly will definitely affect the intended outcome. I'm not a speed guy, but reading about all the others who do it regularly, there's more to be considered than just mounting a rocket. Should be fun to watch when your done.

 

[arelee]

I’m not a fan of doing rockets, but there is a guy on YT already doing it

Thank's for the video jondilly1974. I'm not into rockets either. Never owned one. It just seems like something cool to try out.

 

[arrmadillo]

I'm not into rockets and not a scientist, so that doesn't make me a rocket scientist lol
But it's interesting and someone has to do it, keep us posted, and some vids!

 

[arelee]

Mounting a rocket?. Since you plan on running it on flat surfaces, I don't think any extra bracing is needed, but you might consider raising the dif fluids, especially in the center. 500k or 1M to keep the balance from front to back. Changing just the pinion isn't the only thing to consider. You might want to change the center spur as well. Gearing this beast properly will definitely affect the intended outcome. I'm not a speed guy, but reading about all the others who do it regularly, there's more to be considered than just mounting a rocket. Should be fun to watch when your done.

Thank's Notorious J for the dif. fluids and spur gear advice. I put them on my list of 'things to do'.

As I mentioned above, I've never messed with rockets before. Just something to try. In regard to speed, it's simply one of the other things I want to try with my cars.

Where I live, there are mostly gravel roads and pastures. That's why I chose the Kraton 6S and 8S. Strong and versatile RC cars.

Thank's again for the info.

 

[Branson_Basher]

Here's something to consider, when you mount the rockets consider the angle of thrust and it's effect on down force at the front wheels.

These rc cars tend to get "light" at the front end when run at high speeds. As soon as the front end gets light you loose steering traction and once the front comes up off the ground your speed run is over.

If you angle the rockets to provide some down force to the front end you'll be able to hit higher speeds.

 

[arelee]

Here's something to consider, when you mount the rockets consider the angle of thrust and it's effect on down force at the front wheels.

These rc cars tend to get "light" at the front end when run at high speeds. As soon as the front end gets light you loose steering traction and once the front comes up off the ground your speed run is over.

If you angle the rockets to provide some down force to the front end you'll be able to hit higher speeds.

Thank's Branson_Basher. Great point! Definitely on the list of variables to consider. The location of the rocket= high or low in the rear of the car, along with your advise should keep the nose down.

I'm not into rockets and not a scientist, so that doesn't make me a rocket scientist lol
But it's interesting and someone has to do it, keep us posted, and some vids!

Hey arrmadillo, nice to hear from you again. Thank's again for the help with my batteries and charger.

I'm in the same boat as you. Not a rocket scientist.

I don't own a cell phone. I'm retired, so a land-line is all I need out here in the country. I do have a still camera, so I can include photos, if I can figure out how to do it.

 

[Branson_Basher]

More thoughts on front end mods; lower the front suspension and use heavy shock oil. Suspension travel is not your friend at high speeds...

An air dam on the front end will help keep your rocket car from taking flight. It'll be tough to get one low enough to block all air from getting under the front end and keep enough ground clearance for running on gravel but any improvement here will help.

Study the front end of Formula 1 cars to see how you can design a front clip that gives maximum down force. Come up with something that will cover the entire front 1/3 of the car, including tires, and attach it right on top on the lexan body. It'll be a lot of work but it's probably the least amount of work you'll have to do if you want to hit enough speeds to make this project worth it.

Have you worked with thermo forming plastics before? Kydex is pretty easy to work with and is inexpensive.
Carve a mold form out of wood and form the kydex to it. I'm sure there are youtube tutorials that'll walk you through it.

Another route would be buying a lexan body for an 1/8 road car and cutting the front 1/3 off, then graft it onto the Arrma body.

There are several ways to get the job done but however you do it adding down force to the front end must be done.

Watch some of the youtuber guys do speed runs and you'll see that keeping the front down if the practical limit to a speed run.
"RC Speed Week" is a good series that illustrates how all cars come up in the air before reaching the top speed the motors/gearing can provide.

Good luck!

 

[r4nd0m]

hmm and here I was thinking someone modded the Kraton with a supersized jet engine ...

 

[arelee]

More thoughts on front end mods; lower the front suspension and use heavy shock oil. Suspension travel is not your friend at high speeds...

An air dam on the front end will help keep your rocket car from taking flight. It'll be tough to get one low enough to block all air from getting under the front end and keep enough ground clearance for running on gravel but any improvement here will help.

Study the front end of Formula 1 cars to see how you can design a front clip that gives maximum down force. Come up with something that will cover the entire front 1/3 of the car, including tires, and attach it right on top on the lexan body. It'll be a lot of work but it's probably the least amount of work you'll have to do if you want to hit enough speeds to make this project worth it.

Have you worked with thermo forming plastics before? Kydex is pretty easy to work with and is inexpensive.
Carve a mold form out of wood and form the kydex to it. I'm sure there are youtube tutorials that'll walk you through it.

Another route would be buying a lexan body for an 1/8 road car and cutting the front 1/3 off, then graft it onto the Arrma body.

There are several ways to get the job done but however you do it adding down force to the front end must be done.

Watch some of the youtuber guys do speed runs and you'll see that keeping the front down if the practical limit to a speed run.
"RC Speed Week" is a good series that illustrates how all cars come up in the air before reaching the top speed the motors/gearing can provide.

Good luck!

Hey Branson_Basher,

Thank for all of the information. Although most of the roads here are gravel, a few of the paved ones are long, straight and not used much. Perfect for speed runs.

I'm going to order a full set of shocks and tires, to be used for speed runs. Do you think that 30W motor oil would work in both the front and back?

I've never worked with thermo forming plastic. Seems like a good plan. Definitely looking into it. I have an extra, new clear body that I plan on modifying for the the rocket platform and any other mods.

Thank's again for all of the useful information.

Have a great Christmas!

 

[arelee]

One of the reasons that I decided to get back into RC cars, after 37 years, was because I watched the David Windestal youtube video, "Recreating the Mythbusters rocket car (with a RC car)". However, he ran a 1/10 scale, Hobby King "Desert Fox". I wanted to go bigger.

I bought a Kraton 6s and an 8s. After getting the low down on how to properly use LiPo batteries, from some great people on "Arrma Forum", I am ready to learn what it will take to run the car(s) at top speed, then engage a model rocket, that will be built into/ onto the car(s), starting with the Kraton 6s.

Currently, aside from swapping out the the stock bearings with sealed bearings, the car is stock. I'll start by upgrading the motor, ESC, pinion gear and tires. What would be the best combination of these parts, to get the highest top end speed? Next is the rocket mounting system and location.

I am new to model rockets. From what I've read, size "G" engines are the largest that can be used without having a level 1 certification. Anybody know anything about model rockets? From what I've read, an Aerotech, G54W-14A White Lightning is VERY high thrust, and, no HAZMAT charge= normally $35.00, (I think).

The rocket motor mounting location and platform are crucial. I have some ideas, but any suggestions would be great. This is going to be fun!

UPDATE:
After taking all of the suggestions that everyone has given me here on this thread, and looking at some other threads, (and more research on the internet), I have decided that the Kraton 6S might not be the "best" choice of car to use for this experiment. The (2) that seem to fit the bill, (while staying in the ARRMA family), were the Talion 6S and the Typhon 6S. I chose the Typhon 6S. BLX V4. , and just ordered one from Amazon, along with "Fast Eddiy" bearings. Haven't told my Kraton 6S yet, (I don't want to hurt its feelings on Christmas day).

 

[Clubin]

I would leave the shielded bearings. They have less drag than a rubber sealed bearing.
If you are just doing speed runs every bit helps.

 

[arelee]

Thank's Clubin, makes sense to me. I'll send the others back.

 

[LibertyMKiii]

Is there a certain goal that you have in mind?

Edit - just read that you got a Typhon.
The gearing is quite different on this. 26t pinion and 34t spur I did 90mph on Monday.

For speed you want
Stiff springs (Limitless setup works great)
Low ride height (droop screws)
Locked diffs (silly puddy or 2 mill fluid)
Spool (again limitless works best)

People go wild with big motors but as this video shows the BLX motor is capable with the XLX esc.

 

[arelee]

Hey LibertyMKiii,

Wow, that is one fast car! Nice work.

I chose the Typhon over the Kraton 6S, because I will get a faster top-end speed without having to change the ESC and motor, just the pinion and spur gear. At least for now,(at least that's what I hope). It's just a better car than the Kraton for fast, straight runs. The rocket will hopefully take over when the car maxes-out. At least that's the plan. Thank's for the useful information. However, I have a few questions:
1) What are "droop screws"?
2) What does "spool" mean?
3) I'm thinking 20 tooth pinion and 38 tooth spur gear. What do you think?
4) Your speedometer, I can only read "Garmin". What model is it, and how do you hook it up to the car? I have to get one!!!

You really know what you're doing, regarding speed.

Many thank's.
Merry Christmas.

 

[LibertyMKiii]

Hey LibertyMKiii,

Wow, that is one fast car! Nice work.

I chose the Typhon over the Kraton 6S, because I will get a faster top-end speed without having to change the ESC and motor, just the pinion and spur gear. At least for now,(at least that's what I hope). It's just a better car than the Kraton for fast, straight runs. The rocket will hopefully take over when the car maxes-out. At least that's the plan. Thank's for the useful information. However, I have a few questions:
1) What are "droop screws"?
2) What does "spool" mean?
3) I'm thinking 20 tooth pinion and 38 tooth spur gear. What do you think?
4) Your speedometer, I can only read "Garmin". What model is it, and how do you hook it up to the car? I have to get one!!!

You really know what you're doing, regarding speed.

Many thank's.
Merry Christmas.

Just to clarify that is not my YT Channel or car, just providing an example of the capabilities of the stock motor.
With the Typhon I would do 28 tooth pinion and 34 tooth spur. That should take you to the 95-100 mph range on stock electronics.

The Garmin is a discontinued model called a forerunner (models 201,301,401) still can be found used on eBay.
Skyrc makes one just make sure it is their latest model gsm-015

droop screws adjust ride height on the 6s models. It is a screw in the a-arm that rests on the chassis limiting the travel.

A spool replaces the center diff and locks front and rear versus the diff action of the original center diff.

 

[arelee]

Just to clarify that is not my YT Channel or car, just providing an example of the capabilities of the stock motor.
With the Typhon I would do 28 tooth pinion and 34 tooth spur. That should take you to the 95-100 mph range on stock electronics.

The Garmin is a discontinued model called a forerunner (models 201,301,401) still can be found used on eBay.
Skyrc makes one just make sure it is their latest model gsm-015

droop screws adjust ride height on the 6s models. It is a screw in the a-arm that rests on the chassis limiting the travel.

A spool replaces the center diff and locks front and rear versus the diff action of the original center diff.

Thank's once again LibertyMKiii for the valuable information.

I'm going with the Skyrc gsm-015.

 

[arelee]

Is there a certain goal that you have in mind?

Edit - just read that you got a Typhon.
The gearing is quite different on this. 26t pinion and 34t spur I did 90mph on Monday.

For speed you want
Stiff springs (Limitless setup works great)
Low ride height (droop screws)
Locked diffs (silly puddy or 2 mill fluid)
Spool (again limitless works best)

People go wild with big motors but as this video shows the BLX motor is capable with the XLX esc.

Hey LibertyMKiii,

When you suggested "Limitless" parts, I thought those were aftermarket parts. Now I know. The Limitless is one cool looking car. After I beef-up the Typhon with all of the best electronics, add a set of GPR TO1 Revo (S2)=soft compound , belted tires, incorporate your suggestions,(and other suggestions),include the rocket, I will test it. If all goes well, (and the car doesn't go up in flames), I will buy a "Limitless", take the upgraded electronics from the Typhon and put them in the Limitless, and add another rocket. Should be fun.

Bye the way, will the Limitless shocks and spool you suggested, drop into the Typhon, or do they need to be adapted?

Thank's again buddy!

 

[arelee]

More thoughts on front end mods; lower the front suspension and use heavy shock oil. Suspension travel is not your friend at high speeds...

An air dam on the front end will help keep your rocket car from taking flight. It'll be tough to get one low enough to block all air from getting under the front end and keep enough ground clearance for running on gravel but any improvement here will help.

Study the front end of Formula 1 cars to see how you can design a front clip that gives maximum down force. Come up with something that will cover the entire front 1/3 of the car, including tires, and attach it right on top on the lexan body. It'll be a lot of work but it's probably the least amount of work you'll have to do if you want to hit enough speeds to make this project worth it.

Have you worked with thermo forming plastics before? Kydex is pretty easy to work with and is inexpensive.
Carve a mold form out of wood and form the kydex to it. I'm sure there are youtube tutorials that'll walk you through it.

Another route would be buying a lexan body for an 1/8 road car and cutting the front 1/3 off, then graft it onto the Arrma body.

There are several ways to get the job done but however you do it adding down force to the front end must be done.

Watch some of the youtuber guys do speed runs and you'll see that keeping the front down if the practical limit to a speed run.
"RC Speed Week" is a good series that illustrates how all cars come up in the air before reaching the top speed the motors/gearing can provide.

Good luck!

Hey Branson_Basher,

Just wanted to let you know that after taking your advice, I checked-out the aerodynamics, and "Kydex". I came to the conclusion that the Kraton is not the best platform for this project. The Typhon 6s BLX v4 seemed to fit the build, so I bought one. Haven't received it yet. I also got a clear, spare body. With modifications, the Typhon body should produce far better results than the Kraton.

If everything goes as planned, (including the rocket). I am going to try the same thing with a "Limitless". Have you seen what they look like?!

Thank's again man.