The biggest muppet ever!

[Macsgrafs]

Well today I took the plunge, having spent many many hours on the sim practicing all sorts of things, from hovering to autorotations. I went out with my Blade 400, weather nice & sunny, wind speed about 5 MPH, if that. Up she went (no training gear...1st mistake), I hovered her about 4 ft off the ground, then I noticed the tail wagging..landed her rather hard & broke a skid mounting arm, no worries I thought let's get her up again...bad move! Should have sorted out the gyro to try & stop it hunting. Any way, up again she goes & she's trying to get away from me so i have to turn her nose in & bring her back...slowly does it. then a apply rudder to turn her away from me & she starts to crank over to the right, apply a bit of left...BLADE strike..too slow Mac Damage is limited to main blades, broken support strut for the skids & scuffed tail feathers, so I have ordered all the parts, only a few quid....this time!!!!
This Blade is a right pain. I had already sorted out the tail wagging in my studio once before, yet she seems to be doing it again. I have seen so many reports on the crap gyros in this bird, that I'm begining to wonder if I should by a Titan 325, they seem so much smoother in flight.


Oh well, I've learnt a nasty lesson today..all that glistens isn't gold

Regards
Ross

[Icewizzard88]

Yes i have had that issue once but I usually have a slow spinup everytime no matter how bad I want to hover and it seems to do well, if I get hasty it gets twitchy on lift off. I also changed the throttle curve in the DX6i transmitter to be a bit smoother. Granted I AM A NOOB but Radds school of flight and patience has paid off, only hovering not still hover but no crashes yet. Radds is a good way to learn.

[Aztek1701]

Hi there,

Wagging on a model is usually indicative of one of three problems..

1. There is stiffness somewhere in the linkage between the tail servo and the tailblades. This could really be anywhere, from the pushrod to the tail pitch slider. ESPECIALLY on the 400 sized models, the tail linkage needs to be really free. To test.. Disconnect from the tail servo and move it by hand. If it feels stiff then you need to find out whats causing it an free it off. Usual culprits are the ball joints on the bell crank or the tail pitch slider assembly. You can buy a ball joint reamer that will free off the ball joints without making them sloppy.. silicon grease or oil sometimes helps too. Id be willing to bet that this is the problem on your 400 since its a pre assembled machine.

2. Gain in transmitter is too high... Every gyro is different but try reducing the gain. The wag may go away but if it stays but just gets slower look back to 1. If the gain is too high you'll get a wag whatever happens. The trick is to get it as high as possible without the wag.

3. Static tail pitch not right... All driven tail helis need a certain ammount of static pitch at centre stick on the rudder to counter the helis normal torque. (Its ususally about 5 - 6 degrees) If its too much or not enough the head hold system in the gyro then has to work extremely hard to maintain the heading. Result, it doesnt quite make it and the tail wags. The test for this is (if your competent) flip off the head hold in a hover with neutral rudder. If it suddenly pirouettes then this is the problem. You either need to adjust the length of the linkage between the tail servo and the bell crank or move the servo slightly up or down the boom to adjust the pitch.

Radds school is a good way to learn. Keep at it guys

Take Care... Azzy

[Macsgrafs]

Originally Posted by Icewizzard88

Yes i have had that issue once but I usually have a slow spinup everytime no matter how bad I want to hover and it seems to do well, if I get hasty it gets twitchy on lift off. I also changed the throttle curve in the DX6i transmitter to be a bit smoother. Granted I AM A NOOB but Radds school of flight and patience has paid off, only hovering not still hover but no crashes yet. Radds is a good way to learn.

I have followed radds school of how not to crash & seems to work fine. But there comes a point when you just have to get the heli off the deck & that's as far as I have got, it was fun but nerve racking.

Ross

[Macsgrafs]

Hi Azzy, thanks for the tips. I disconected the push rod from the tail servo & it is very smooth, no binding or sticking. I did use a screw driver on the gyro a few days ago as it was doing the tail wagging then, it seemed to cure it until yesterday when it had come back. On Saturday I am going to an indoor meet with a few others that fly helis, I will get one of them to fly it & get there comments.

I see you have both the 450 & 600 trex, which one is more stable? These small helis are so skittery, I have even used +25 expo on cyclic to try & sort it out, still a very nervous heli...any ideas how I can take a bit of life out of this bird?

Regards
Ross

[Aztek1701]

Hiya,

The 600's are easier to fly... no question.. They are better designed machines too just a little bit pitchy at medium slow forward speed (this is a trait of trexes though). My 450 isnt too bad considering its really a dememted bumblebee in disguise , it runs 2500+ RPM at the head (its a 4 cell setup). I Im running 30% expo on it though lol. If you want to tame yours down a bit, try weights on the flybar. That clams them down a bit, that + expo. The other thing that might help is winding up the headspeed a bit... You'll need to find the sweetspot though because too high and they turn into hornets and too low and they become very "fidgety".

Hope this helps... Azzy

[Macsgrafs]

Thanks Azzy, some really informative info there. I didn't know that adding weights on the flybar calmed things down, just got to find something to do that with. I could up my expo a bit as well i suppose, 30-33 insted of the 25.

Again many thanks for the much valued input.

Regards
Ross

[Aztek1701]

Im told wheel collets for planks do the job well. Also I think align supply them as part of the kit for the 450's now so they should be available as spares. These should fit your blade. They work because they increase the mass and inertia of the flybar and therefore the ammount of effort needed to move it. This in turn affects the helis flying.

As far as the expo goes... Theres no harm in trying it. If you dont like it, roll it back off again.

Good luck with it ... Azzy