I see that the tail rotor can be either engine or head driven.

Can a single heli be set up either way (like on the Raptor 30 for example)? I'm wondering because when it's engine driven that can cause problems in normal mode... for example when in-flight taking collective all the way down and then back up again.

Cheers

Hi,
The tail drive is dependant on where the drive is taken from. This is a matter for the main gear/ sprag bearing etc. You can get different gears for helis to make them a driven tail drive, or non driven (speaking from the main blades ). A non driven tail is not driven by the main blades during an engine failure (or practise auto) and while you have little/no rudder control to change where the nose is pointing, you have more energy at the bottom of an auto to make landing a little easier. On a 50 size heli you can auto with a driven tail, there is enough energy stored in the rotor system. On a 450 electric you have only about 25% of the energy you get in the 50 heli, so a non driven tail would be much better, then again, electrics seldom need to auto.

So, yes you can change a heli from one to the other, but you can't set one up for both.

With regard to dropping you head speed in normal mode and low collective, set up your engine idle for about 1/4 trim, before takeoff increase your trim to full. Now even when your throttle/collective is all the way back, you have some power to help keep head speed up.

Thanks. Answered not only my main question, but also explains the reason for tail rotors not being driven via the head. Especially on a really small heli it would definately be bad to bleed the energy to the tail which is useless for an emergency autorotation.

I was worried that certain 30 size heli's might be permanently engineered to be not-head-driven on the tail. But you say that you can change that in the mechanics? That's what I was hoping to here. I'm thinking of getting the Raptor 30 v2. Is a 30 size not sort of on the borderline in this regard? In other words that the tail could be head driven while still being able to autorotate reasonably well?

But it's also a good option to adjust the low end engine rpm.

Thanks

Hi again,
Speaking of autorotation, I found this "optional part" for the Raptor 30 called the AUTO ROTATION GEAR (PV0379). Apparently it relates somehow to the tail pully. I can't find a description of it. What is this exactly? What's it for? Again, it's an optional part.

Thanks

EDIT: come to think of it, could that part be what you need in order to make the Raptor 30's tail rotor head-driven?

Hi,
This is the information given on Midland Helis web site for the above part.

PV0379 : Auto-Rotation Tail Pulley - 30/50
Autorotation Tail Pulley for the Raptor 30/50. This gives a driven tail on autorotations. This item is standard on the Raptor 50V2.


I have not used this part as the Titan has a driven tail but autos fine.
From the description it sounds to me that the Raptor 30 has a non driven tail.
can someone confirm or correct this please?

You're correct, stock the R30 has the red tail gear which makes the tail non-driven in an auto.

It's no big deal, you just need a little forward speed and it will weathervane into the wind. Some folks do it, some folks mod the 50 to be non driven to get extra hang time. Personally if I had a 30 I would leave the tail drive stock.

Thanks guys. Ok good to know that I know what part to get if I do get the R30 and wanted to mod it. And I have some better perspective now on the issue as well.

All things considered thus far, I'm starting to consider getting a 50-size electric instead... partly because of the whole autorotation issue. I like the R30 though, but have to consider this still further.

Cheers