I cannot seem to make a fast fighter, with decent attack power.
I cannot do a double engine with a single weapon without going over power.
Any help? Ideas?
1 weapon, 1 power plant, 2 engines, no armor. Don’t worry if you end up with two "engine 1"s instead of two of the more powerful engines. Also, if you really love fighters, use Rebels. Rebels are known for having the best fighters, and GSB continues the tradition.
Yeah, you can get a speed 2.65 laser fighter with Rebels. Icarus with one laser, one Power Generator II, one Engine III.
EDIT: oh… and with the right combination of TWO engines, as Teatime suggested, and power plant, I found a Icarus that goes 2.68… Laser, Power Generator I, Engine I, Engine II. Only costs 1 resource more (90), and has 20% more HP (23 instead of 19)! Nice 
I would consider this to be the ‘best’ laser fighter design possible at the moment (at least unless destroyed fighter armour modules become repairable in carriers.)
Really though, at the moment it’s still the case that if you need to kill other fighters, you need to go antifighter missiles and tractor beams (you need the tractor beams for dealing with the insanely fast rocket fighters that can be made without power plants - I can make one that goes 4.60! Dirt cheap, but only one rocket, so it’s not dealing much damage… But it’ll survive the battle, and if the enemy tries to intercept it with fighters, it’s effectively taken those fighters out of the battle. Fastest I can pull with two rockets is 2.99.)
tell me about this rocket fighter, I have really only been using laser
Well, you’ve basically got three choices of weapon for your fighters…
Laser = anti-fighter, and with suitable orders (set to 100 range so you are often firing within the shields) can eat cruisers and frigates too. Versatile.
Rocket = anti-frigate. No use against anything but the slowest fighters, and harmless to cruisers unless something has brought the shields down already… But they chew up frigates fast, except the most heavily armoured ones. Since you can often build these fighters without a power plant, they tend to be very cheap and very fast.
Torpedo = anti-cruiser. Slow, easy to kill, and often expensive. But if you use them wisely (i.e. make sure they don’t get attacked by enemy fighters) they can deal tremendous damage. Capable of demolishing cruiser shields and armour.
A well coordinated mix of the three, can take down many of the challenges people have posted. Lasers deal with the enemy fighters, rockets with any anti-fighter frigates, and torpedoes show up last to speed up the process of killing the cruisers.
so what about fighter to fighter, speed and laser right?
can i set that order then let them sting the cruisers?
Yeah, speed and a laser. Speed beats armour, at the moment, once you get over around 2.5 speed.
However, once you get to around 2.6, 2.7 speed… Your fighters will dogfight each other for a very long time, don’t expect them to get anything else done. If they end up chasing anything really fast, like a speed 2.98 rocket fighter (or the ridiculous 4.6 speed one) then the battle will end before they get done killing them. For this reason, you cannot forgo mixing some frigate/cruiser antifighter (antifighter missiles and/or tractor beams) into your fleet, no matter how good your fighters are.
I usually give laser fighters orders to target fighters at 100%, and cruisers at 1%, so that I can set them to fight the cruisers at 100 range (inside the shields.) If you just leave the attack cruiser order off, I’m not sure what range they try engage at.
fastest I have gotten is 219
what race are you using for almost 3?
Rebels. Their fighters are unmatched, with high hull power AND a speed bonus. The Icarus is the best fighter hull, IMO, with the Achilles a very close second.