Pitch gauge accuracy

[Guest]

Just a quick and potentially silly question. What do you use/how do you setup to ensure your flybar is set level with the heli when using a pitch gauge. It seems a little difficult and ineffective to do it by eye as I think this needs to be bang on to ensure an accurate reading when we need to tell the difference between 0 and 1 degree.

Cheers
Jack

[sacko]

On the Blade 400 (twister 3d), you can put your flybar paddle through the blade holder.

[Grant85]

What about this to lock the flybar in place if you wanna be bang on

http://www.fast-lad.co.uk/store/130-...ck-p-4784.html


Cheers Grant.

[electricsceadu]

i use a spirit level that hangs on the flybar and use a flybar lock
i also make sure the bench and airframe are level before i set the pitch
as its no good setting the flybar level if the airframe isn't

[Astronobaldo]

What I do (not sure if that is correct or not) I removed one of the vials from a level tool (like this one, for example: http://nextday.diy.com/app/jsp/produ...roductId=35466). Then I place it in the flybar to check whether or not is lined with the heli.

I hope that helps.

Cheers,

[Grant85]

These may help you mate

[ame]http://www.youtube.com/watch?v=L02UlMgxy9E[/ame]

[ame]http://www.youtube.com/watch?v=r7-eU5uwcQk&feature=related[/ame]

[ame]http://www.youtube.com/watch?v=hZN_SGs8UEk&feature=related[/ame]
http://www.rchelimag.com/pages/scope...cope=29&page=1

Plus check this site out too:

Cheers Grant.

[Guest]

Thanks guys, great response as ever - question answered

[Grant85]

Thanks guys, great response as ever - question answered

Good,glad your sorted now.Let us know which approach you took in order to get the flybar level and how well it worked.I'm thinking of making such a device too
The second video i posted may not work for you as there is no space between the Twister frames to put the foam block like there is on a T-Rex 450,so maybe the third video might be a better idea.
Cheers Grant.

[Guest]

Cheers Grant. I will have a go tonight and let you know. Did not spot the other two videos until this morning so will watch them later too.
Jack

[unwind-protect]

It seems to me that not getting the flybar exactly perpendicular to the main mast is one of the more minor ways of introducing error to reading blade pitch.

It seems to me you get far bigger errors from not having the blade pulled out straight, by not having the pitch gauge on straight, by looking at the gauge/ head from a slight angle, and on smaller helicopters from the amount of slop in the head, none of which ever seemed to get talked about much.

[Mart61]

Forgive me for I may be wrong in this. However, the only use a spirit level based tool will be is when the heli itself is level. As such you'd have to check that.

Even further, when you check the heli is level, what are you using as a datum? The skids? The main blade grips? What?

It is my opinion that the important thing is not that the flybar is level, but that the flybar is perpendicular to the main shaft.

As such on the T-rex 500 I simply slid a 4mm allen key between the main shaft and the flybar see-saw holder. See Finless Bob's video here - you need to forward about half way thru (10mins 10secs) and see how he does it.

On your heli it may not need a 4mm key but perhaps a 3 or 5 may do the job?

Bob's your Uncle!

[Holst]

Forgive me for I may be wrong in this. However, the only use a spirit level based tool will be is when the heli itself is level. As such you'd have to check that.

Even further, when you check the heli is level, what are you using as a datum? The skids? The main blade grips? What?

It is my opinion that the important thing is not that the flybar is level, but that the flybar is perpendicular to the main shaft.

As such on the T-rex 500 I simply lid a 4mm allen key between the main shaft and the flybar see-saw holder. See Finless Bob's video here - you need to forward about half way thru (10mins 10secs) and see how he does it.

On your heli it may not need a 4mm key but perhaps a 3 or 5 may do the job?

Bob's your Uncle!

Thats a very good idea

If the flybar is at 90 degrees to the mainshaft then its in the correct position.

I think as long as you get use the same method on both blades then you wont end up a long way out. A slight difference in pitch wont make much difference to how the heli flys.. unless its different side to side and makes your tracking go wrong.

[Mart61]

I think as long as you get use the same method on both blades then you wont end up a long way out. A slight difference in pitch wont make much difference to how the heli flys.. unless its different side to side and makes your tracking go wrong.

I fully support this. It's the same when we diet. OK our bathroom scales may be inaccurate but, in theory at least, they should always lie by the same amount. As such, when they say you've lost (or gained) a few pounds, they should be correct. They may have your actual weight half a stone out, but the comparative weights should be correct.

The same is true of a pitch gauge. As such, so long as you're using the gauge the same way on both sides, you should be ok.

[electricsceadu]

to get the heli level i use the top mainshaft bearing block
provided that it square to the mainshaft (the top of the holder as some are shaped , i'm not saying the bearing is not square cus it should be)

[Mart61]

to get the heli level i use the top mainshaft bearing block
provided that it square to the mainshaft (the top of the holder as some are shaped , i'm not saying the bearing is not square cus it should be)

Yep - that'd work. But so does the allen key trick and for a fraction of the cost/time.