Copy files without encryption (ssh) in local network

You might be looking for rcp, it performs remote execution via rsh so you will have to rely on that and have in mind that all communication are insecure.

You cannot disable encryption completely on ssh/scp but you can force it to use a weaker cipher that is much less cpu intensive. Make sure that compression is not turned on in your ssh_config or on the command line and add -c arcfour,blowfish-cbc to your scp command line to select weaker ciphers.

I wrote this quick script:

#!/bin/bash

ssh "$1" "nc -l 2020 > \"$2\" &"
pv "$2" | nc "$1" 2020

It takes two args, the host to send it to and the file you are sending. It only works for one file. It uses ssh to start a netcat listening on the opposite end and then uses netcat to send it to that listening port. I added pv to the start to give a nice progress bar. Replace pv with cat if you don't have or want that. Change the 2020 port to whatever you like. This requires you to have ssh access to the remote system.

This is completely insecure, but then, that's what you wanted.