Tail blow out

[kenny d]

Hi guys , what makes the tail blow out on pitch pumps ? , i have tried the gyro gain in the transmitter with
no affect , ( trex450 tt & beastx ) I mostly find this problem on 450's , regards Kenny d

[Grumpy]

If it's a proper 'blowout' rather than just a big wag, then i'd suspect you are running too low headspeed or using a 'normal mode' sloping throttle curve rather than a constant headspeed setup.

[Hamish]

Batteries, I have found that if the batteries are not up to the job, they will bog the rotor which then can blowout the tail. As well as that pitch pumps are quite demanding. What packs are you using??

[kenny d]

I've got a few different makes , one is a new 2200mah opti , so don't think it's the batteries , I am running 100% on throttle flat or 85% flat ,

yeh proper blow out sometimes I can get a 360 , it is a standard 450 3gx , nothing changed except beastx

Transmitter is set all the same for all my 450's , so don't think it's got anything to do with that

mechanical set up as per manual

[bigpops]

Pitch pumps aren't normally bad for a blow out in my experience, you normally just get a kick while the gyro/servo catches up. It's usually a fast funnel or backwards loop with plenty of pitch that makes the tail give up. If you're getting a 360 piro, something is wrong somewhere.

Tweak pot 3 on the mircobeast (turn it clockwise), and see if that helps. The I gain might be too low if everything mechanical is sound.

[bigpops]

I read it as he'd swapped the 3gx for a Beast X and that's when the problem started.

I can't help with the 3gx, I've never owned one.

[kenny d]

I read it as he'd swapped the 3gx for a Beast X and that's when the problem started.

I can't help with the 3gx, I've never owned one.

the model was a align 450 3gx , I have changed the 3gx to a beastx , the tail has always been bad , I just read a bit about the dual slider which mine has , there is a mod for it , on HF some one says the tail will never hold without the mod , I'm going to look into this and precomp (F in parameters menu) , Kd

[kenny d]

Originally Posted by bigpops
Pitch pumps aren't normally bad for a blow out in my experience, you normally just get a kick while the gyro/servo catches up. It's usually a fast funnel or backwards loop with plenty of pitch that makes the tail give up. If you're getting a 360 piro, something is wrong somewhere.

Tweak pot 3 on the mircobeast (turn it clockwise), and see if that helps. The I gain might be too low if everything mechanical is sound.

ive tried pot 1 , 2 , & 3 with no joy , Kd

[myxiplx]

I can't speak to your model specifically, but the advice above is all sound. If it's a genuine tail blowout then you simply don't have enough force available on the tail.

On my Gaui X3 the tail performance improved dramatically when I changed one of the pulleys to increase the tail ratio, and also when I added larger blades. It's got a lot more 'oomph' behind the tail now and it really locks in nicely no matter what I throw at it.

Another option is to increase your headspeed, a higher headspeed with less cyclic pitch will give you a model with similar feel on the cyclic and collective, but which then has a lot more rpm on the tail, and hence more tail authority when flying those same moves.

[tomatwalden]

parameter menu F : page 27 .. http://www.bladehelis.com/ProdInfo/F...-Manual_EN.pdf

F. Tail—RevoMIXThe AR7200BX can pre-compensate for torque variations on the tail before anynoticeable change. RevoMIX relieves the tail control loop and improves tailperformance on helicopters with insufficient tail authority and/or high poweredelectric helicopters

[tomatwalden]

...
yeh proper blow out sometimes I can get a 360 , it is a standard 450 3gx , nothing changed except beastx

..

If it really is a full blow-out (sounds like it is), then the only thing that could cause that really is a loss of aerodynamic anti-torque from the tail rotor. Pre-compensation on collective will avoid a wag by mixing in tail in advance of the increase in torque, but at best it would only hide a real problem if one exists.

One possibility is that something is slipping under high load. Is this a belt-drive for example - is the belt slipping under load? Or if a torque tube, is something slipping.

Common trick is to hold the tail rotor still then (fairly gently), see if you can turn the main rotors keeping the tail still.

[Grumpy]

Too low headspeed is still the more likely cause, low headspeed = low tail rotor speed = low tail rotor authority.

So what headspeed are you running and are you using a fixed headspeed (gov or V curve) or a sloping 'normal mode' throttle curve?

[kenny d]

maybee I've not got enough to information on this post or some people are not reading it right , but all imput is appreciated lol

[kenny d]

As stated above , the model is a trex450 3gx tt ( torque tube) , it's the model directly before the DFC , the only thing that has been changed is the 3gx has been changed to a a beastx ( not ar7200bx) , the battery I'm using for setting this up is a brand new opti 2200 mah , it has a proper blow out ( not a wag ) , I've tried the gyro in the transmitter & the 3 pots on the beastx with no joy , It's running 100% head speed in the transmitter



ive got a new set of 450L dominator tail blades coming this morning they are longer than standard so I'll try them , I was going to try tail precomp but not so sure now
the ball on the servo horn is in the same place as my other 3 450's so don't think it's that , the tail mechanism is free flowing so not sticking at all , if I start the pitch pump slow for the first 10% then fast it holds ok , thanks again for any suggestions Kenny d

[Grumpy]

With a flat 100% throttle curve in the Tx it shouldn't be a headspeed issue.. I'm kinda out of ideas then, if you are getting full pitch range travel and have high headspeed the tail hold should be solid.