RC India

Hi,

I recently started building a Hiller 450 v2.

I noticed that the tail rotor in my heli came on the left side, although in the build videos by sujju, it is on the right side.

Can anyone tell me if mounting on left side makes any difference?  :headscratch:

I tried searching here but to no vain (may be using wrong key words?). Found few random posts in google leading no where.

Links to more reading material on the tail rotor would be greatly appreciated.

Thanks

PS: Changing it back to right side is a easy solution but this is more of a learning exercise. :)

Left or right doesn't matter for a zero pitch aerofoil. Google For images of Mi-8 heptr, it has tail rotor to either side, aim is that the tail rotor should counter the torque. It is like pusher and tractor aeroplane , viewed from front both rotate anticlockwise,

Hi Augustinev,

Thank you for the response but I have two issues now  :banghead:

1) Zero Pitch Aerofoil
By this you mean the tail rotor system is a zero pitch aerofoil? I was under the assumption that gyro/rudder servo controls the pitch of the blades i.e. the angle between plane of rotation and the chordline so the pitch is not zero? Am i lost?  ???

2) Angle of attack (Angle between airflow and chordline)
Doesn't the angle of attack change (assuming certain pitch in the blades) due to the left hand side placement thereby changing the direction of force? If this happens shouldn't the gyro be acting likewise i.e opposite to what it would in-case of right hand side placement?

I am unable to test the gyro practically as I do not have everything in place  :(

a fixed pitch prop has (Depending on the side it rotates) has a positive pitch for a zero deg plane of rotation. whereas a 4D prop, main rotor tail rotor has zero pitch at aero deg plane of rotation. idea is it should work efficiently to both sides (i.e to turn the tail both sides, well) when the tail rotor system moves it about, it now goes into positive or negative angle of attack depending on which side you want the tail to be moved. that does not matter to which side of the tail boom the rotor is.

to put it simply , with the heli nose to your right if you view the tail rotor and say it is angled to push the nose to the right it will do so irrespective of which side of the boom it is on (Not considering design limitations)

Although I have not tried it, but I feel that it should make no difference. Setting the direction of the servo and gyro correction may be required.

 I Think you can also rotate the tail assembly to match the standard way. I will check in my heli.

Nice Information augustinev  {:)}  :thanks:
The below is precisely the line I was looking for. 

Heli is so much fun for someone who loves physics  ;D

@asupan - End effect wise it makes no difference as augustinev pointed out. The differences can be seen when one goes into the theory and dynamics of the system.

I'd have expected Sujju to respond here since this is specifically about a Hiller. I don't have a Hiller, but would mention a couple of observations from other models that may or may not apply to a Hiller.

The amount of tail slider travel is not symmetric on all models. Remember the neutral position is not zero pitch. Some of them have just enough travel when assembled the right way. Your travel will be less than required if assembled on the wrong side.

The tail housing has guide roller for the belt on the slack side in some models. It'd end up on the tight side on your installation.

Some models have tail servo in the main frame which would rule out swapping sides. Hiller seems to have tail boom mount, so no issues on this front.

It takes some effort to get the geometry and travel right in helis as it is. I wouldn't complicate matters by deviating from the intended configuration. I'd take the time to fix it now than fret about it at a later build stage.

thanks karthik for the pm or i would have missed this thread altogether...
theoretically gusty is right and this should work as far it counters the centrifugal forces of the main rotor and yes the gyro and til pitch slider should be working amended to compensate for this new setting... i have seen a few mikado Logo helis in this way recently...
However, with changing the tail to the left hand side then the issues like the belt roller (like rajesh's statement) will come in play and would not recommend you to play around with this unless arrangements are made to compensate this...
infact for the sake of experiment i will try to change this configuration on one of the Hiller basic that we have when i am in bangalore in the next few day if possible and will try to post the outcome here

sujju

Sounds good Sujju. Thanks

@RotorZone - Precise Information - Duly noted.  :thumbsup:

Also I am into helis particularly for the build part of it, so a little pain here and there in the set up is not an issue  ;) . So far simulator has been serving the purpose of flying a heli and I have my cars for bashing and fun part  ;D

For now, I guess Ill go back to the normal set and get it up in the air as suggested.  I'll definitely do the experimenting at a later stage.