My approach to this is for simple heli recovery. I found it more suitable to my needs. Airfoiling is the TRUE way to do this, especially if you're doing competitions. Since I'm not, I like the simple plan better. Glad to help. Hope to see a video of your flight.
My avatar pic is of my scratch-built 'copter, concepted when I initially became a "born again rocketeer" last December after many many years away. Not having known just how far the sport had progressed, I wanted to create something "original, something no one had ever thought of". Unlike the earlier attempts which were largely body tubes with large fins and flaps that deployed to spin them down, I wanted a true set of dedicated "rotors". Hah! Fast forward a few weeks only to discover that not only did helicopter recovery already exist, there were even NAR events dedicated to this genre!
Never been able to get a video, things happen too fast even on just a C engine. Maybe I could borrow a true videocam, one that can track and zoom real good so I can stand way the heck back.
For a first attempt the thing boosts ridiculously straight and I have to admit airfoiling the rotors really made a difference. It actually comes down slower than a rocket with a chute. Plus, well...it looks cool too.
Just started on a featherweight eRockets kit model (Heli Roctor) that employs the same slice and bend technique. I'm curious to compare the spin and descent rate of this vs my airfoiled one. Granted the eRockets model weighs in at 26 grams and mine at 57grams (with engines installed), allowing for scale, I think the lift generated by both rotor designs will have a large effect.