Scale OH-6A "Cayuse" (450 size)
- Thread starter danhampson
- Start date
Lee
Well-Known Member
Hi Dan.
I'm pretty sure the reason for the tail problem is.
You have changed the tail to the opposite side of the boom.
But you haven't changed the rotation of the tail. Its no longer turning the tail in the correct direction.
Tail blades should turn up into the down wash not with it.
Also because the tail is now on the other side, the torque from the main blades means most of the work in the tail is lost from the deflection off the boom.
Normally the tail airflow would be unit erupted by the boom for the important job of fighting the Main blade torque.
Solution.
1) Rotate the tail belt the opposite way, flip the tail blades. This should give the tail more authority.
2) This could take more effort. Rotate the one way bearing in the Main gear. swap two motor wires to allow the main blades to turn the opposite way.
There for allowing the tail to fight the torque in the opposite direction, giving the tail clear airflow to push against.
I'm pretty sure the reason for the tail problem is.
You have changed the tail to the opposite side of the boom.
But you haven't changed the rotation of the tail. Its no longer turning the tail in the correct direction.
Tail blades should turn up into the down wash not with it.
Also because the tail is now on the other side, the torque from the main blades means most of the work in the tail is lost from the deflection off the boom.
Normally the tail airflow would be unit erupted by the boom for the important job of fighting the Main blade torque.
Solution.
1) Rotate the tail belt the opposite way, flip the tail blades. This should give the tail more authority.
2) This could take more effort. Rotate the one way bearing in the Main gear. swap two motor wires to allow the main blades to turn the opposite way.
There for allowing the tail to fight the torque in the opposite direction, giving the tail clear airflow to push against.
Lee
Well-Known Member
Hi Dan.
I'm pretty sure the reason for the tail problem is.
You have changed the tail to the opposite side of the boom.
But you haven't changed the rotation of the tail. Its no longer turning the tail in the correct direction.
Tail blades should turn up into the down wash not with it.
Also because the tail is now on the other side, the torque from the main blades means most of the work in the tail is lost from the deflection off the boom.
Normally the tail airflow would be uninterrupted by the boom for the important job of fighting the Main blade torque.
Solution.
1) Rotate the tail belt the opposite way, flip the tail blades. This should give the tail more authority.
2) This could take more effort. Rotate the one way bearing in the Main gear. swap two motor wires to allow the main blades to turn the opposite way.
There for allowing the tail to fight the torque in the opposite direction, giving the tail clear airflow to push against.
I'm pretty sure the reason for the tail problem is.
You have changed the tail to the opposite side of the boom.
But you haven't changed the rotation of the tail. Its no longer turning the tail in the correct direction.
Tail blades should turn up into the down wash not with it.
Also because the tail is now on the other side, the torque from the main blades means most of the work in the tail is lost from the deflection off the boom.
Normally the tail airflow would be uninterrupted by the boom for the important job of fighting the Main blade torque.
Solution.
1) Rotate the tail belt the opposite way, flip the tail blades. This should give the tail more authority.
2) This could take more effort. Rotate the one way bearing in the Main gear. swap two motor wires to allow the main blades to turn the opposite way.
There for allowing the tail to fight the torque in the opposite direction, giving the tail clear airflow to push against.
Last edited:
danhampson
Member
Thanks Lee.
As for the solutions.
1. the heli im using a 450 pro so its TT
2. is the only other choice. And would look better for scale.
15 mins later.....
Just flipped the owb in a spare hub so going to take the mechanics out the fuse and install the flipped bearing and set the tail and head up accordingly.
Slobberdog
Well-Known Member
You might have to flip the mounting orientation in the gyro make it think its upside down so it compensates for the new rotor direction, and anti torque correctly,
Just a thought
Just a thought
danhampson
Member
rotor direction shouldnt make any difference to the gyro but will the anti torque. i will have to see if telling the gyro its upside down that it will make the right stability corrections.
danhampson
Member
ive completed the left hand rotation mod swapping the control edge for every blade every thing is working fine, ive not done anything with the 3gx i want to give it a fly first.
Last edited by a moderator:
Lee
Well-Known Member
As you have found out. changing the main blade rotation, has done the first mod for you anyway. Now the tail is correct because the torque tube is being turned the other way.
Glad you got it working mechanically right.
Now make sure to get all the electronics compensating in the correct direction
Glad you got it working mechanically right.
Now make sure to get all the electronics compensating in the correct direction
danhampson
Member
been out and tested, all gyro correction directions correct, spooled up smooth and lifted off nice (a bit strangle the heli drifting right) but the nose is rotating to the right, i had to hold about half left rudder for it to hold.
I think that Kev is right about the torque precomp.
So any ideas welcome guys? (apart from get an ikon)
I think that Kev is right about the torque precomp.
So any ideas welcome guys? (apart from get an ikon)
Lee
Well-Known Member
Get an IKON hahahahahha
The gyro doesn't distinguish left or right. So it will just compensate for what ever it feels is happening.
The mechanical pre comp will be wrong, again because you have changed sides. Setting the pitch slider in the middle will give the tail blades negative pre comp to what is needed.
You will need to set the pitch slider to give around 8º of pre comp against the main blade torque, Or. and this is just from the top of my head, as i don't have a 450 in front of me. You could flip the tail grips to be leading edge controlled rather than trailing edge, which should give you centred pitch slider with the correct pre comp blade angle.
Also you would then have to change the servo direction and gyro direction for the tail.
You will have to verify this yourself and let me know if thats right.
The gyro doesn't distinguish left or right. So it will just compensate for what ever it feels is happening.
The mechanical pre comp will be wrong, again because you have changed sides. Setting the pitch slider in the middle will give the tail blades negative pre comp to what is needed.
You will need to set the pitch slider to give around 8º of pre comp against the main blade torque, Or. and this is just from the top of my head, as i don't have a 450 in front of me. You could flip the tail grips to be leading edge controlled rather than trailing edge, which should give you centred pitch slider with the correct pre comp blade angle.
Also you would then have to change the servo direction and gyro direction for the tail.
You will have to verify this yourself and let me know if thats right.
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danhampson
Member
yeah your right Lee on the mechanical side just gone over the set up and the mechanical was out ive not changed the tail to leading edge just extended the control rod (all corrected now), also the anti torque comp direction doesnt affect the cyclic gyro correction direction so ive changed this too.
Charging packs up now so hope to get out in the next hour.
Charging packs up now so hope to get out in the next hour.
danhampson
Member
no change in the tail behavour, in fact it was better with the main blades rotating in the correct direction. I came down a bit hard and stripped some tail gears and snapped the OH-6A tail fin. I will have to order some parts to get her fixed and hope that i can repair the tail fin.
danhampson
Member
I think I might have found the tail problem. It looks as if there may not be enought support for the tail push rod. I've found some parts to do the job so I'll have a look tomorrow, got to go to work now.
danhampson
Member
Re: OH-6A "Cayuse" (450 size)
Just thought I'd update, the project hasn't stalled, I've just had to put it on hold for a while due to me recently losing the battle against physics and gravity.
Just thought I'd update, the project hasn't stalled, I've just had to put it on hold for a while due to me recently losing the battle against physics and gravity.
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danhampson
Member
Not this one Lee. I need something other than my 150 to fly, I've come to the conclusion that micros aren't really my thing. I'm hoping to get this project back on the go at the end of June.