I'm neither a real pilot or engineer but it would seem to me that a longer, more slender body would lead to less rudder control, not more. Torque is one thing though he speaks of yaw to either direction. Torque rolls one way, with the propellor.
Even the statement about out turning a -51, hmmm. And no one plane can out turn/fight/BnZ, etc five or six planes. A zero can't, a Tempest can't, even the mighty 262 is going to get hammered eventually. The very best stick in our game is not going to beat 5 or 6 average joes in one furball.
I don't know though I am a bit sceptical of his words.
Boo
Well Boo, its not uncommon to defeat a mob if you have the right pilot in the right fighter.
A few years ago, when I was a trainer, Murdr, TC and I were holding a wingman tactics clinic in the TA. We had a pretty good crowd, a mix of noobs and vets looking to learn new skills. After the clinic ended, we decided to see what everyone had learned.
I took six guys and gave them the task to shoot me down (or at least hit me enough to equal that). Two were in P-51Ds and four (all from Saxmans's squad) were in F4Us. I was flying a 109G-2.
We flew out in opposite directions until beyond icon range and reversed to merge right on the deck. Within a few minutes, all six were in the tower. Everyone of them had been shot up, and I forced all of them to auger. Meanwhile, my 109 had not suffered a single ping. They grumbled and complained, so I took a P-38J for the next round. Net result was identical. Murdr watched both fights and commented that they quickly forgot everything they were taught immediately after the merge. Rather than cover one another, they flew in a closely grouped mob, making it easy to keep an eye on all of them. Once I had them slow, I took the fight vertical and was able to pick them off almost at my leisure.
In a fight like this, dealing with a group is not that difficult. Your only concern would be the arrival of higher aircraft while you are maneuvering with the mob. That happened in the second fight, because they would immediately re-up after crashing. Thus, I had to watch for them returning with altitude and E. That didn't help them much.. I would abandon the guy I was working on and climb out to meet the new threat, knowing that the low and slow guys would not be able to climb up and re-enter the fight for a few minutes. Long enough to deal with the returning guy(s). What makes this type of fight more problematic in the MA is that you will have many different types of fighters arriving at various altitudes and E states, making it much harder to track all and stay aware of their relative E states. You could be down in the weeds, flaps out and find one or more guys above you looking for the pick opportunity. The MA is a much more complex and uncontrolled environment.
I may or may not still have some films of these fights, but Murdr can testify to the accuracy of the above.
So, the answer is, within a controlled environment, one guy in a 109K-4 can certainly engage and defeat five or six guys in P-51s, depending upon the skill levels involved and tactics utilized. If they all commit to maneuvering with the 109, the task gets easier.