Bruh...69% of my messages are just memes and shitposts
Well, there are two three points that needs to be addressed before we can do something like this
• Redundancy
Typically, the whole idea of a FTB is a plane that can do everything on its own and have an extra engine duct taped to it. So, it takes off with its own power, attains a stable altitude, slowly starts the "test article", increases till maximum revs, all while asymmetrically lowering its own thrust so that there isn't any turning moment due to this weirdly placed engine, collects data, turns the engine off, lands with its own power. With time and confidence, the time interval in which the test engine is run is increased, ultimately running from before take-off to after landing. So, the summary of all this
Satyanarayana Katha is that the only job of a test engine in a typical FTB is feeding gigs worth of data every minute; that's it.
But in case of a single engine UAV like CATS, the same engine that needs to be tested is also the one responsible for every single thing on the FTB from propulsion to electricity generation. This can seriously mess up your redundancy.
• Data Analysis
More or less an extension of the previous point. Let's say your Boeing 737 based test bed is testing Kaveri in a pod attachment and suddenly there's a flameout or even a near catastrophic failure. So let it be! The plane would simple land unscathed, the whole pod would be removed and shipped to DRDO or HAL and they'll have a thorough investigation on the cause.
But let's say this same happens on a small, single engine CATS with Kaveri test engine. Now you'll first need Belgian Malinois to search God knows how many square kilometers of area to find all the bits and pieces of the engine and then do analysis of whatever you find.
• The good ol' SWaP that I keep bringing
Here's the rough size of Kaveri compared to that of CATS
View attachment 25321
The proportion is huge also you'll be now on very limited fuel because on one hand you're consumption is going up and on other your internal volume is going down.
• Stability
Take the example of the famous Pratt & Whitney FTB. It's 150 tonnes Boeing 747 so it's bit tough for a single test engine to unstabilize it. And even if it does then also you have four onboard engines producing 800kN of thrust that can balance it out. Now consider CATS; a 2t MTOW plane where 1t is just Kaveri with dry thrust of 50kN...a TWR of whopping 2.5; basically a rocket.
There's is absolutely no doubt about the novelty of this idea; a unmanned drone is definitely going to perhaps even be a better FTB than a manned one...but sadly not CATS; it's too small. It's like asking whether it's a good idea to add a 105mm gun in a lighter platform. Yes definitely it is, but that lighter platform can't be a jeep.
You'll need a big, multi-engined UAV like this maybe
View attachment 25322
But then the age-old question arises, viability.
How viable it is to make just one-piece UAV from scratch when you can acquire a retired airlines and modify it?