Old Tech here

@zander OOps, I meant 2.4KHZ.

@old-tech That's 1,000 times too low.

@old-tech Where are the relays located, and what do they do?

How do you plan on controlling the speed and direction of the tank.

Do you plan on having the turret rotate? If so, how?

Relay logic can be configured just like an H block.

It requires 8 relays to do this for two drive motors.

I will clean up the drawing and post it later.

Amazon.com: HiLetgo 12V 8 Channel Relay Module with OPTO-Isolated High and Low Level Trigger 8 Ways Relay Switch Module for Arduino : Industrial & Scientific

The schematic on the left side

20 vdc battery reduced to 12vdc, and another 20vdc battery to power the blower.

I do not want the battery to die and leave the unit on the roof.

A PWM to control speed placed at the drive input of the relay.

FTVOGUE 12V-40V 10A PWM DC Motor Speed Controller Module Governor Stepless Variable Speed Control Switch : Amazon.ca: Tools & Home Improvement

It is a complicated configuration, but I am near completion.

As to turret rotation, the toy tank had that in place and included the motor with gears. Will have to make a mounting system.

Past relay experience:

In my time as a tech there was a Lamson Pallet loader that was completely relay logic. 4 cartons were placed on a slide by a conveyor, then squeezed to hold them, the slide moved out from under the four cartons. Then an elevator rose up and the four cartons were released to be set onto the awaiting elevator. The elevator descended. The slide closed and the process was repeated. There were over 60 open faced relays that were set to delays by bending the contacts. There was tube PEs to trigger the actions. That was my early time with relay logic. It progressed into electronics and the first IC I saw had 14 pins; it was 1"wide x'4"long x 3/4" thick with three on a board. I progressed from there. They never taught us that in Tech Jr. College in the 1960 time. Then there were industrial lasers that operated off of 5000 volts DC that had to be adjusted in an open-air method.

@old-tech Ok, it sounds like it is coming together for you, all the best.

@zander Read it once more please.

@old-tech I did, what is it you think I am missing?

I added additional comments, that I thought you missed.

@old-tech I saw that.

So, live and learn.

The 20vdc batteries did not work, so, I used one of the 12 vdc Dewalt batteries and everything is great.

I have all of the circuits worked out. 

Learning about the new boards and their functions has really made putting this together easier.

PWM is a great tool.

I have incorporated it.

I sold my scope years ago, so I got a small dual trace coming. 

As I plan to use two motors on each side, I wanted to look at pulse width.

I am waiting on several items so I can make this work with smaller boards.

This crawler is just an experiment, and if it works, I will go with larger motors on another unit.

@old-tech What do you mean that the 20VDC battery didn't work, was it dead?

2 motors driving the same track will likely be impossible to synch and my hunch is you will get less torque as a result.

Once you know how much torque you need, just find geared motors that give you 1/2 that.

Have you got it to the point where you have remote control, or is it a wired setup?

@old-tech 

I was curious if anyone else had built a remote controlled robot blower that could be used on a roof.
https://make.co/contestants/remote-controlled-robotic-leaf-blower/

@robotbuilder That is a beast. Keep in mind the maker is a retired Electronics Engineer. He also needs a lifting mechanism to get it on the roof as it weighs 25lbs.

What struck me, though, is how ineffective it appears especially when compared to the hose end devices.

@zander 

Maybe @old-tech could combine removing leaves with cleaning the roof.

https://lpahjgonline.top/products.aspx?cname=roof+cleaning+robot&cid=166

@zander Getting both motors to run on parallel may reduce the torque, but I hope not. I will sync them with the scope once I get it.

@RobotBuilder: I appreciate your effort to find a working model.

I have got to hand it to the builder, He was smart enough to think ahead and get a lift to do the lifting. I am still in the development stages. I put the tracks together today. I have to take it to the shop and fabricate a base that I can attach the tread motors and idler wheels to. The treads have to be expandable to keep the treads tight. Meaning slots and screws. That part is done. Then I have to put the electronics on a non-conducting board and mount it onto the bot base with Stand offs and a plug in for the 12 vdc battery. I have the plug-in prongs ready to mount. My plans are to use a Dewalt 12cvdc battery to run the electronic remote and motors, then a 20vdc to power the blower. That is yet to come. I am still waiting some parts. 

Keep in mind this build is not the real deal, only a test unit to see if a turret mounted blower will work.

Once I get some idea of what need to be changed, I will go to #35 conveyor chain with fabricated treads which well take time to make. then get two: uxcell DC12V 60W 60RPM 8N.M Reversible Worm Gear Motor High Torque Speed Reducing Electric Gearbox Motor-JCF63R - Amazon.com to complete the big rig.

I have all winter to either do this or drop it.