Lucky escape

Had a great days flying today, however on the last flight of the evening I noticed that the tail was waggling as if the gyro gain was too high mainly at the 12 o’clock of a loop while trying to keep it inverted NO H/H then I thought I will try it with H/H but it was no better.
The tail also waggled badly on a roll!
Have any of you guys had a similar problem?

I landed the heli to check it out why the tail is waggling; this is what Leigh found.






The paddles have jammed themselves in front of each of the leading edges of the blades.





Any ideas to what could have caused this ?
How is it possible for the heli to fly this the way it is!


I have checked the gears, all seem to be okay no missing teeth or anything like that.

Any advice is welcome

Thanks in advance.

Zaidy

Looks normal to me?!

Its normal on Mark B Heli not mine LOL

Heh heh! Birdstrike?

zaidy goes flybarless. There was no noise or anything to indicate this happening it gust got a bit lively and looked like the gyro was fighting. Very lucky escape

The thing that is baffling me, is not so much that they are bent, but the fact they have bent forwards. That pretty much rules out them hitting anything in flight....

I can't see any of the forces involved with rotating "bits" being to blame either, because they would want to fling things outwards as far as they can go. That would mean there is a natural tendency for the bar to want to straighten itself, not bend forward as shown.

Perhaps you had a mid-air with my AWOL rocket, the Faaaaark!?

Andy

Hi Zaidy
The picture shows the paddle flybar has bent forward in normal rotation direction to reach the trailing edge of the main blade ahead.
Interesting problem

PDQ wrote:Hi Zaidy
The picture shows the paddle flybar has bent forward in normal rotation direction to reach the trailing edge of the main blade ahead.
Not just one paddle half but both paddles.
Theory 1
Each paddle/flybar half has been pushed forwards by the following main blade
i.e. the blades swung forwards
Theory 2
The engine stopped dead/the main shaft stopped dead. But the blades carried on and clocked the flybar and paddles

Were they mounted stiff or sloppy ?
Are there any marks on the blades to show any impact ?
How close is the blade track to parts of the fus when extrem pitch changes occur ?


Interesting problem
There must be an explanation

Hi Paul

I think you and Dave S are on the same lines and Leigh suggested a missing tooth on the gears but on inspection all was in order !
Were they mounted stiff or sloppy ?
The blades are mounted just tight
Are there any marks on the blades to show any impact ?

Yes there are scuff marks on the leading edge of the blades, the paddles were jammed in front of the leading edge I freed them once I landed.

How close is the blade track to parts of the fus when extrem pitch changes occur ?
Not sure how to answer this one ! I have seen videos of guys throwing the heli in the sky very aggrissively and no damage and yet get have this from doing a few loops and rolls!

Regards
Zaidy

Solution !

Don't do loops and Rolls.....yet

I'm wondering if this has happened whilst spooling up the heli on the ground, before lifting off, rather than in the air?

Think about it for a moment. Engine is turning over, head is not. Spool heli up, and the clutch kicks in a bit aggressively. This causes the main blades to fold back enough to slip under the flybar paddles (or over, depending on where they were when you landed). Head accelerates, causing the blades to be forced back to their normal position due to the reactive centrifugal force on the main blades (things thrown outwards when rotated). Fly bar paddles are caught on main blade leading edges, so get bent with them.

Flight continues, but due to slightly deformed flybar, control response is a little odd!

Sound plausible? I think it is a bit of a longshot really, as I didn't think the main blades could pivot back enough to catch on the flybar paddles. I could be worng though?

One question, was the odd handling noticable throughtout the entire flight, or did it suddenly occur?

Cheers
Andy

We're all guessing really.
There is no concrete evidence apart from the photo. Only a few saw it happen.
Baffling

A couple of more pics
Slight damage to the trailing edge as it folded



Where it impacted and caused the slight damage


Regards

Zaidy

Andy Sayle wrote:I'm wondering if this has happened whilst spooling up the heli on the ground, before lifting off, rather than in the air?

Andy

That would be my thought, other would be if you were doing auto practice, when you spool back up if you have loose blades the force when the clutch bites will kick the blades round,

At a good head speed the blades wont move due to the forces involved

I think lol

Good escape though

M

The head speed wouldn't drop enough in an Auto to allow the blades to kick around more than 90° would they? Or would it? I guess it depends which school of autorotations you subscribe too (there is a really obvious joke that could be used now, but I won't, I feel I have mocked this forum member enough for today )

Those pictures are supporting the theory blades folding back on spool up, Zaidy

Andy

Andy Sayle wrote:I'm wondering if this has happened whilst spooling up the heli on the ground, before lifting off, rather than in the air?

Think about it for a moment. Engine is turning over, head is not. Spool heli up, and the clutch kicks in a bit aggressively. This causes the main blades to fold back enough to slip under the flybar paddles (or over, depending on where they were when you landed). Head accelerates, causing the blades to be forced back to their normal position due to the reactive centrifugal force on the main blades (things thrown outwards when rotated). Fly bar paddles are caught on main blade leading edges, so get bent with them.

Flight continues, but due to slightly deformed flybar, control response is a little odd!

Sound plausible? I think it is a bit of a longshot really, as I didn't think the main blades could pivot back enough to catch on the flybar paddles. I could be worng though?

One question, was the odd handling noticable throughtout the entire flight, or did it suddenly occur?

Cheers
Andy

I guess its possible !
The heli handling was okay I think, but became odd on inverted as the tail waggled, Leigh was by me all the time and I remember saying oh the gyro is struggling high up it must be very windy up there !