Lightweight alloys alone is not enough to get it to 600... you have to make other sacrifices, especially HD shield boosters and prismatic shields, and as a result you end up with a fast ship that is no longer able to hold its own against an FdL which doesn't have to make such sacrifices.
This is the lightweight version of the Mamba I was using in Beta 3:
https://forums.frontier.co.uk/showt...-)-Mamba-PvP?p=7193244&viewfull=1#post7193244
Didn't win every fight I was in (though I did actually win every fight against every Phantom I fought 1v1), but I was a match for some well piloted FDLs and it was a pretty durable setup. Mostly had trouble with ships that had several focused PAs...something I'll need to work on countering (probably with focused PAs of my own, now that a large and a huge won't melt the ship) once the Mamba settles into it's more or less final state.
The 'heavy' version I now have on live still does 582m/s boost and has ~600MJ more shielding (over 2k of fast charge bi-weaves) than the one I was using in Beta 3. Obviously, it can't boost as often, which hinders it's PA evasion a bit, but it's also got the buff to heat dissipation and rotation that it didn't have in Beta 3.
I think theat fdev dont fully understand why the fdl is so prevalent. Its the combo of pitch, acceleration, speed, hardpoint convergance and shields that make it so good.
They know, but I don't think they want to duplicate it, for good reason.
Anyway, the Mamba doesn't need to outbrawl the FDL to have a niche, but it does need to be different in a way that isn't synonymous with 'suck'.
What else is is good for? Unless you can give me an example of a non-combat use for the Mamba, I'm going to treat it as a pure combat ship - and that's where it is objectively worse than its direct competition (FdL) and subjectively worse at combat than a few multi-role ships!
Oh, it's definitely a combat ship, but it's still not an FDL and the same loadouts and tactics that work well with the FDL will not be ideal with the Mamba.
I could be pidgeonholing the Mamba here, but currently it takes the FdL as a starting point and makes it worse in every way that matters - agility, shield strength, ability to evade (lateral thrusters + huge hitbox), internals for HRP/MRP, weapon convergence. What it claims to offer in exchange for those downsides is speed and cheap boosting, both of which were taken away in Beta to make it much more like an FdL.
Beta 4 did make it more like the FDL, which is unfortunate, but I don't feel the situation is as dire as you make it out to be.
- It can still evade ok because it still has silly good forward and reverse acceleration; just tapping reverse at an opportune moment will cause quite a few projectiles to miss their marks. Forward and side profile is also comparable to the FDL, even if it's a proverbial broad side of a barn from above or below.
- Internals are a wash...4/3/2/2 is barely worse than 4/4/2/1 and the Mamba has slightly higher base hull integrity.
- Hardpoint convergence is decidedly worse, but hardpoint sizes are generally more useful, unless you lock yourself into the all PA/rail 'meta' (which exists for a very good reason, but is far from the only viable weapons loadout). Most non-rail/PA medium weapons suffer fairly extreme damage reductions against the hulls of higher-tier combat ships, but large weapons do not. There are also some weapon types that get dramatically better from medium to large in other areas.
- It's speed is still a good deal higher than an equivalently fit FDL, which does matter.
- Also, it doesn't have the FDL's propensity to stall if you are less than perfect with throttle/thruster management.
Edit: This was more true of the Beta 3 Mamba, but even the live version is a bit more tolerant than the FDL. However, something about the flight model seems to make ships more likely to do this the faster they can rotate (possibly simply to to them reaching the opposing vector more quickly), so it may lose what's left of this advantage if it's buff the 'wrong' way.