chinese weights

[moyesboy]

Over the BH I did the chinese weight mod to the tail of my 450, which is mostly trex but for the sonix superframeand a load of otherstuff. The tail mech is genuine align but driven by acarbon rod old style (not sure why the wire is supposed to be better).
tail is 401/FS61BB with stdcurvy ended plastic align blades.

I just got the chance to fly it.

It wagged on piro stop until I reduced the gain to 72% from 82% (on gear end points).
piro rate is up about 50% which I guess is like a mechanical gain increase.
It bounced a lot on piro stop, and now i have a bit of delay (25%) to cure it and performance seems pretty good but darkness and small field size restricted things.
Piro rate seems more constant in a ripper (falling out of a stall turn piroetting), as would be expected if the piro rate has increased purely from the mechanical setup.

so, in my opinion the blade bris should have these weights on as standard.

I used stainless raptor TT balls and tapped the blade grips m2 just outboard of the bearing. Search helifreak if you don't know what the chinese weight mod is.


to cut a long story short, the blade aerodynamics and the weight of the blade grip control arm make the blade grips want to turn to zero pitch when the tail is revolving. these weights want to turn to 90 degrees pitch when the tail spins. Thus they blance those forces out, at least a bit - so less servo power is needed tocontrol the tail.
Even on a 450 the forces making the blades want to go zero pitch overpower a decent digital servo - otherwise why does my heli piro faster with these weights on? So I should get better tail performance, and better servo life.
We will see, but it looks good so far.

[jiberjaber]

I had a NIX tail gear set on mine - which in effect is the same thing, cant say I noticed that much difference. Back to the old align tail set now since the last big crash and not a difference to be seen.

I guess if there is less stress on the servo (which from the demos I have seen on the web appears to be the case) then that is a good point.

[moyesboy]

With CSM720 on my other two helis the lack of consistent piro on my 450 has been annoying me. But not over the last week 'cos I've flown nothing except the sim.

[Boggy]

there is an article about this kind of mod (c.r.w. centrifugal restoring moments) in mays mhw magazine. is that where you got the idea Gordon??

[moyesboy]

no, not seen the mag. I first saw it here, or trextuning, and there was a bit of dicussion and a link to helifreak about it. Plus I tried to figure out what the balancing was about on the nix tail that robgt had and reviewed at trextuning.

[robgt]

the nix tail that robgt had and reviewed at trextuning

Which was excellent!
Sadaly, a lack of spare parts for it meant it got retired when a blade pitch lever broke

Cheers,
Rob

[barney]

moyesboy..something worth trying is upping the acceleration gain in the gyro on the 450 by a good margin (try 140%) worked well on the older 560. Allows you to increase your normal gain a good bit. If that works you could try balancing it out at a lower setting if need be.

There is just something the CSM's dislike about small heli's..and you get this little bish bosh (think car wipers) unsecure feeling. I disagree that the rex500 for example needs a full size tail servo to work well. It does seem to be Gyro specific.

The Spartan DS760 for example with a 9257 gives a very good tail on the 500..can't really fault it..It's so darn good I've not even had to change the standard plastic tail blades.

cheers Brian

[moyesboy]

The 450 has a 401, so no adjustments other than gain and delay.
The 720 gyros are on my 600n and knight 3D. Maybe soon I'll get to fly them again...

3 packs through my 450 tonight and the tail is now very very good, and seems to have a much more consistent piro. but lack of flying has made me all nervous and twitchy.