Do you think 180hp can actually lift 5000lb 12 inches vertically?

[SolarEagle]

I decided to test the sim in an unusual way, though I imagine the more you try to push the limits the more inaccurate it becomes. I thought it would be ineresting to see how many pounds I could lift with a rotor powered by a 4cyl piston engine(R-22).

I managed to get 5000lb about a foot off the ground, and at 3500lb gross I managed to build enough speed to clear a tree line. Seems the amount of air pressure generated when the rotors are near the surface is quite a lot considering it was enough to suspend 5000lb, but that pressure seems to drop off drastically with every inch of clearance. I found that part of the modeling to be quite interesting.

Do you think this is accurate at all, or is there no way 180hp rotor can lift that kind of weight, if even only 12 inches?

[Wulf190]

I'd like to think it could, but I'm a pilot, not an aero-engineer. My C-172RG grosses out at 2,650lbs, and it's powered by a 180hp Lycoming O-360-F1A6. Anything above that weight and it's a no go.

Granted with me and my instructor we were roughly around 2400lbs. The Cutlass seemed to fair just fine at the weight and handles well, as long as your aware of it's nose heaviness when compared to a regular C-172.

But while I'd like to think it could lift 3500lbs or even 5000lbs; I'd rather have more power.

[gajit]

Hi SolarEagle

Its been a while since I flew the R22 in the real world. Ground effect, air temperature, wind speed can all help. To enalble a departure heavy we were taught to "cusion creep" where you hover taxied faster and faster low to the ground to transition into flight so that the ground cusion would reduce the power required. I cant remember the max all up weight but full fuel and 2 fat blokes could fly on a hot still day.

[Lionheart]

........and the cushion is called 'ground effect' where you can easily hover when the ground is dectable (felt) by the rotor disc thrust area. Once higer though, that drops off..

This is the same with airplanes and even airliners.

For instance, the Airbus A-320's are notorius for 'floating down the runways' using their brilliant glide capabilities along with ground effect to 'float' down the runway. This is bad, by the way. You should touch down as soon as possible before you run out of runway, so with Airbus drivers, you have to learn to put that thing down (force it down) or you keep flying down the runway.

Helo's are quite a bit different though..


If you get a chance, next time the documentary on Igor Sikorski comes on, watch it... Utterly fascinating how he develops helicopters into safe, small little craft with small engines and basic frames and rotor assemblies... All made from scratch on a little chicken farm. Amazing pioneer...



Bill

[SkippyBing]

Cushion Creep is one use of ground effect, another is VOGE (Vertically Out of Ground Effect) where you drop from the usual ~5 ft hover down to a foot or so above the surface which frees up some extra power. You then pull through to max continuous power to climb vertically up and as you clear whatever obstacle is in your way start to apply forward cyclic to start the transition. Obviously it's important to check you still have a rate of climb on before you start the transition, if not you just come back down again and have a think about it.
For more on how to fly helicopters to the limit your best bet is to read Chickenhawk.

[SolarEagle]

Intersting stuff, thanks for the info.

I assume the Sikorski documentary is the one I've seen a few times on the military channel, and it is indeed very good and quite fascinating.