Multi Blade Rotors

[pitviper51]

http://flying-hobby.com/catalog/prod...oducts_id=1996

hi,, was wondering if anyone here has flown a 3-4 blade heli.. does it make it more stable?????? i want to try and build a scale belt cp. i have yet to decide on body, but a 3- 4 blade would be needed to complete,, mostly wondering if it helps with stablity, thanks!
mike

[Flyinfool]

Typically multi blade heads are much more difficult to setup and fly.

[pitviper51]

i was expecting to hear more sensitive,, i do under stand why they are harder to set up.. at this point on just pondering hehehe
mike

[Flyinfool]

There are many people that end up using gyros for both ail and elev to get some of the systems more flyable.

[Kiwi]

Perhaps the correct answer is it all depends how you do it.

Multiblade heads need to be phased differently. I wont try to explain that here but there area ton of sites with good info on it and why. You can do it mechanically or do it electronically. Electronically is the way to go for lots of other reasons.

OK multi blade heads hate forward flight or a head wind as they flare. Its a by product of multiblade or flybar less heads you can get away from.

So you fit a device called a Helimixer. This does the head phasing and it allows you to fit three gyros (yes not a typo, you need 3) One on the tail as usual and two for pitch and roll. Those gyros really only do a lot of work while your in forward flight. The hover part of things is quiet stable.

And all this info from me is gleaned from a very good friend who just flew his 5 blade Hughes 500E.

If you need any more info I can try to get it for you but again its all word of mouth. I still need to check my shorts after a three minute tail in hover exercise so that gives you expertise on all this.

[DStJohn]

Multi-blade rotor heads are harder to fly on a large heli and on a small electric must be really touchy. I have flown large glow/gas multiblade heads (3, 4, & 5 blade) without the Helitronics mixer. The biggest problem is the heli pitching up in forward flight when reducing collective. You can overcome this with mixes in the radio or add the helitronics mixer & a gyro. I have never flown a bird with the Helitronics in it, but I understand it makes it like a fly-barred heli. If you are flying for fun, and you have the room for the mixer & gyro, I would add it. Of course if the mixer or gyro fails, you are in deep poo! Check out the Helitronics mixer at: http://www.eastcoastvario.com/mixer.htm

If you are building a small electric heli, then I don't think you have the room (or power) to pick up the added weight. You will definately want to use blades designed for the flybarless head. Flybarless blades are weighted more to the outside and forward to add more stability.

[pitviper51]

ok im convinced i dont need multi blades hehe
mike

[jack01]

Could somebody post the link to the info on phasing? I've never played with a 3+ blade head.

[Road Builder]

I've got an old 2 blade flybarless head for a GMP (Hirobo) Legend. I never flew it with this head, but the guy we bought it from said it was tricky to fly. Still have the head, but the heli is gone. I can't imagine a 3+ system being any easier.

Jay

[Kiwi]

You can get the three blade head for the TREX 450 for about $100 on Ebay. Daniel. the guy with the 5 blade Hughes in the above photo flies his 450 Trex three blade with ease but again we are talking scale here and no NO NO!!!!! 3D. No gyros needed, no fancy mixes.

In the hover they are about as stable as a semi stable two blade with a flybar. Again its the moving around bit that gets tricky.

As for the Helimixer there are several other options, one from Hirobo and the other from Vario I think. One of them works like a ball less mouse. Not the animal version guys, the computer one. It takes a visual image every millisecond or so and holds the heli to that spot. It has three inbuilt gyros and apparently makes the whole business a lot easier.

At this years XFC the European boys were flying barless helis like there was no tomorrow. Again I think the system they used is from Hirobo but I will do some research and find out more for you if there is any interest in scale heli and barless helis.

[Road Builder]

Probably from Hirobo. I have an old barless head for a .60 sized bird if anyone is interested.

Jay

[Kiwi]

OK,

The three systems I know of are as follows. There are likely to be more so add them in if you know of any.

http://www.espritmodel.com/index.asp...OD&ProdID=5404

I am pretty sure the FMA auto pilot system would work as well but that will need a manual phasing modification for multi blades.

Helimixer as shown in the link above.

The captron system looks pretty good but not exactly cheap. But if you take three gyros into the equation then the price starts to get reasonable.