Quickie: Do Flakk Missles work?

No. Well, not really. Let's take a look:

It's S7 AP4 Skyfire. This allows you to fire it at your normal BS at Flyers. Now we'll look at how they function against Flying MCs and Flyers vs. an Autocannon (S7 AP4 Heavy 2).

Math Rules
MEQs are the ones to get these so BS is 4 always.
FMC's have toughness 6
Pretty much every flyer is 12/12/10 or 12/12/12 (Necrons are 11/11/11 but whatever)so we'll use AV12 (I'm doubting your heavy unit manages to get behind a flyer often)
They won't be evading or diving (ie no Jink)




Here we go:

Flakk Attack!

versus MC's you have a 3+ to hit and a 3+ to wound. With your 1 shot you thus have an average of .44 wounds. To make this easier that means you have a less than 50% chance of causing 1 wound with your missile launcher.

versus Flyers you have a 3+ to hit and a 5+ to glance. With 1 missile you'll cause a glance or pen less than 1/3 of the time. Nice. You'll have to fire 3 to be pretty sure of a glance (eh 47% sure). Fascinating.

Autocannon

versus MC's you have 6+ to hit and 3+ to wound. With 2 shots you get an average of .22 wounds. Equal to the Flyer 'wound' average for Flakk.

versus Flyers you have a 6+ to hit and a 5+ to wound. 1/9 times will glance or pen. You are again, half as likely to get a single wound.

versus MEQ the Missile Launcher wins again because with 2 Autocannon shots you only cause .37 wounds while with the Krak missle you cause .55 wounds. With the Frag missile you cause .33 wounds average (assuming you hit 3 guys).

However, the missile launcher goes for 25 points while the Autocannon goes for 10. Meaning the Autocannon balances out in price what the Missile launcher makes up for in Strength. 4 Autocannons are 40 points while 4 Flakk Launchers are 100. The 60 point difference can net you even more heavy weapons (albeit on other units). Simply put the Autocannon loses in all measures until you get to price in which the Missle Launcher clearly loses. If the Missile Launcher were to be 20 points instead it'd be pretty balanced out in fact


Conclusion
So, with either, you straight suck at wounding flyers with anything less than 4 of these AND even when you have 4 you will not be able to bring down a Flyer with more than HP 2 in one turn. Neither of them are worth your cash in my mind as the Quad Gun is 100 points total (or 175 with Bastion), gives you cover (or AV14 and 4 Heavy Bolters, ya get the picture) and causes more wounds total on Flyers and MC's than 4 of either other gun (2.37 wounds versus MCs and 1.18 glances/pens versus Flyers). Since you can't move and shoot (well you can with the Autocannon since it's snapshots anyways) a well placed Quad Gun is well worth the money. The Icarus laser sucks because it doesn't have a re-roll and even though it's better and more likely to wound it's much less likely to hit and doesn't have near enough shots to compensate.

TL;DR: Get a Quad Gun. Anyway you can.

For Funsies: Put Telion on it to make every shot Precision Shot!