How to grappling gun speed knockout?

[RoH]

I think this task is listed somewhere in "the dark knight" challenges or whatever. I have to press F and double Space to grapple somewhere and knock out an enemy who stands near to the edge.

I tried that and I know how to speed up,....but I have no idea how this should work.

Usually I'm so fast that I'm jumping over the enemy and start to glide down somewhere....that makes no sense :(

PS: I know that this semi-challenge is described a bit different as I named it but I'm playing the german version where it's called "Greifhaken-Beschleunigungs-Ausschalten". No idea how it's called in english. If you know it, I will edit the header.

Thanks!

[Jay667b]

I had some trouble with it but I found the best way is for them to be standing still by the railing/edge of the building and you directly in line with them before you begin the grapnel boost.

[ElectricGileq]

I have yet to find points where they are actually standing near ledges. Are there some places in the game where bad guys (technically everyone who isn't Batman, it seems) hang out near ledges?

[Uncle Mikoolo]

snipers are easily taken out with that knockout.

[ElectricGileq]

Originally posted by Mikoolo:

snipers are easily taken out with that knockout.

Good point. Thanks.

[Steven Brattac]

grapplehook takedown

[Mr.2k9]

try to do on the building next to the church in park row.... did mine there...
http://www.youtube.com/watch?v=CXkQtUuLe3c
my msi afterburner audio not working properly... cant figure out whats wrong...

[Wolle]

If anyone searches for the right place: Pinguins Final Offer. A sniper at the edge, you know him propably from your first visit.