Quoted:
It's aimed at every poster that believes modifying an existing airframe or resurrecting a large, complicated airplane is no more difficult than making and drawing "plans" and slathering some parts together as if it's some sort of hot rod for cruising the beach.
A casual look at the Sky Fox reveals that the only obvious airframe parts retained from a T-33 is the canopy, and maybe the cockpit structure between the forward bulkhead and the rear seat bulkhead. Now, retaining other components such as the landing gear or even the control sticks, rudder pedals, bellcranks, and so on go a long way to completing an airplane (when the airframe structure is complete, only 90% of the work remains), but all of that has to be incorporated to function in the new airplane, and they probably won't without massive modifications.
The idea of converting a Lear to tandem seating is too laughable for comment. Same with hanging two engines on the outside of the fuselage of an F-86; that one isn't even remotely clever.
The Lear 24 comment was a comparison to the previously mentioned T-33 and F-86 conversions (from single engine planes with late 1940's to early 1950's engines, to twin engine planes with more modern engines). The T-33 conversion moved the horizontal tail higher up, to get it clear of the exhaust and turbulence from the engines. The same would have to be done for the F-86. So in addition to having to rework the structure to support two engines hanging off the sides, horizontal and vertical tail surfaces would have to be redesigned. Toss in the problems that would probably pop up in reworking the fuel system for the new engines, problems that could easily pop up with finding a spot for the engines that doesn't have an airflow issue created by some other part of the airframe, and the weight and balance, and a nervous breakdown becomes a possibility.
In contrast, changing a Lear 24 to a two seater leaves the wings, tail, engines, and fuel system alone. There would still be a weight and balance issue to deal with, but it would be less complicated than the T-33 and F-86 ideas. Airflow could be a problem, but it would seem to be less likely to produce surprises than hanging a couple engines on the side of the fuselage and rearranging the tail. The systems that would need to be altered or moved, would only need changes with their connections to the cockpit. Availability of spare parts and upgrades to systems, would also favor a modified Lear, over a 60+ year old military jet. I didn't say it would be easy. I said that converting a Lear might be less work than the T-33 and F-86 modifications.
And if I failed to make myself clear with the above, I'll blame it on the long day I just had. A retired sheetmetal guy normally comes in as a contractor to help out on certain jobs, but somebody dropped the ball and didn't call him to tell him we needed him, today. So I was working with a trainee, removing the outer three feet or so of the wings, so that they can be replaced with extended sections with wetwing tanks. On this model, I usually just concentrate on the plumbing and leave the sheetmetal to the retired guy and whoever is helping him. Nobody else in the shop wants to touch the plumbing, and if I try to suggest somebody else do it, they just point out that this particular plumbing installation is my design, so I'm "the expert".
You take pictures, make drawingsa with dimensions, write a material list and rough draft of the installation manual, then turn it all over to a DER to amend the STC, and nobody wants to try cramming six cubic feet of crap into three cubic feet of space.
Hopefully, somebody finally remembered to call the retired guy and ask him to come in tomorrow. I'd prefer to get back to just doing the plumbing. If nothing else, it has the advantage of being able to say "do you want to do this?" anytime somebody bothers me, and they usually go away very quickly.