flybarless and blade tracking?

[Delarado]

Guys,

I keep seeing talk of blade tracking on FBL machines. Even my goblin manual mentions it.

I didnt think FBL had blade tracking per-se. If the blades are out of track, the heli will roll/flip and the FBL controller will sort it, no?

[pgkevet]

I think you're confusing swash levelling with blade tracking. You want one thin disc not blades at differing angles of attack giving a two disc appearance edge on.

[SamS]

A FBL controller won't fix a blade tracking issue, you have to increase/decrease one of the linkage arms.

[Chris Boughton]

Blade tracking is when one blade flys slightlty higher than the other, when looking at the blades to track them they will appear tp be 2 rotor discs rather than one, it will still fly if the blades arent tracked but its not reccommened as the peformance will be crap, it wont fly efficiently and use up more power.

[Delarado]

Well this is the thing.

My understanding of blade tracking is blades with differing pitch angles. With FB, the flybar due to its natural horozontalness will adjust to compensate so the heli doesnt tip too violently.

With FBL, if the blades have differening pitch, the heli will roll or flip. And FBL controllers by nature sense this and counteract it. I don't see how blades can be out of track with FBL, because if one blade has more pitch than the other, then the heli will start the move. The FBL Controller will sense this and put in the correction to make the heli not flip or roll, and this by nature will mean the blades are tracking true?

Or am I completely wrong? I just dont understand how a FBL heli can have blades out of track. Surely if you lengthen one pitch link by 2mm then the...hooold on a minute. Ive just realised my mistake If one blade has more pitch, its going to have it for the entire rotation of the disc. So itll just generate more or less lift than the other one but it wont make the heli flip or roll. I get it now

Duhh what a spanner!

[Rctintin]

Do NOT fly with out of track blades!! It causes very bad vibrations and unbalance that will do no good to the sensitive electronics.

Set up your swash to be level (at mid stick), and then set one blade to be at zero deg to the levelled swash.

Now set the second grip to be equal to the first one you have just set like this...



That is 2 lengths of silver steel that are ground to size, thus perfectly straight. (buy them from flee bay)

Adjust the length of the second pitch link to get the bars dead in line and vertical with the mainshaft.

[waveydavey]

Spanner certainly springs to mind

[milly0812]

flybarless and blade tracking?

Fbl is what is says flybar less therefor the box of tricks does what the flybar would do. You can have out of track blades with a flybar so why not with fbl ? ;-)

[tomatwalden]

Blade Tracking & First Spool Up

[Bronek]

Re: flybarless and blade tracking?

Ive just realised my mistake If one blade has more pitch, its going to have it for the entire rotation of the disc. So itll just generate more or less lift than the other one but it wont make the heli flip or roll. I get it now

Yup. And of course this means that direction of lift won't be perpendicular to the rotor disk, meaning ugly vibrations. FBL controlers are sensitive to vibrations.

[Delarado]

Yeah i was just an idiot. I was thinking one blade with more pitch would make the heli roll. When i was explaining it i remembered that the blades actually rotate so it'd generate more lift throughout the entire rotation and so wouldnt induce any roll!

What I do currently is check 0 pitch at mid stick at all 4 points of the rotor disc with one blade. Then I put the pitch gauge on the other blade and do the same. Metal bars idea is a good one though!

[pgkevet]

.............. Metal bars idea is a good one though!

I keep it simlper by dropping a long well fitting bolts through the blade bolt holes and align them with the mainshaft

[Rctintin]

The whole reason on using straight bars is because long bolts are not accurate. The silver steel is a very tight fit in the blade grip holes, and by extending above and below the head, you can easily eye up that the bars are parallel, and vertical to the main shaft.

I have done all my helis like this, and also the 'other' extra models I have had the pleasure of building for other people including TDR's and a Diabolo. I have yet to have a model out of track.

[GIXERMAN]

Yeah i was just an idiot. I was thinking one blade with more pitch would make the heli roll. When i was explaining it i remembered that the blades actually rotate so it'd generate more lift throughout the entire rotation and so wouldnt induce any roll!

What I do currently is check 0 pitch at mid stick at all 4 points of the rotor disc with one blade. Then I put the pitch gauge on the other blade and do the same. Metal bars idea is a good one though!

When you built your goblin you could have used the 0 and 12 degree marks on blade grips as a good starting point.

[r4nd0m]

Yeah i was just an idiot. I was thinking one blade with more pitch would make the heli roll. When i was explaining it i remembered that the blades actually rotate so it'd generate more lift throughout the entire rotation and so wouldnt induce any roll!

What I do currently is check 0 pitch at mid stick at all 4 points of the rotor disc with one blade. Then I put the pitch gauge on the other blade and do the same. Metal bars idea is a good one though!

damn Carl, thats a bit too picky dont you think? what I do I measure the first blade to 0 degrees at 50% pitch - then I do the same for the other - I only had one case where they actually weren't spot on when I took it to the field so I had to work the turnbuckles but thats it ...