HK450 Pro tail control rod

[amedv]

Hi guys,

I am building HK450 Pro and I ran into interesting problem with the tail control rod.
So far, the build was exactly as per Align manual, all parts were exactly the same (and the quality is mostly satisfactory). Slightly different tail mount and tail servo mount, that's all.
And the tail control rod is exactly as Align manual says, 330mm (345mm ball to ball).
But it fell about 10mm too short.
I searched forums for that and some people said the the tail pipe is not all the way in which makes it longer. But the torque tube feels pretty snug, the tail rotor rotates as it should. I can double check, but I feel that I cannot push it in any more.
Some people just made custom control rod... Is that the only option?

Any ideas?

P.S. Sorry if the question was asked before, I honestly tried to search for it for half an hour, but did not find any answers.

P.P.S Yes, yes, I know, the proper Trex 450 3GX is on the way, but I never flew 450 class before , my only CP experience is mcp x, and I wanna crash my HK450 first

[satgod]

turn the servo around so the wheel is closest to the back of the heli

[amedv]

Originally Posted by satgod

turn the servo around so the wheel is closest to the back of the heli

Thanks for the tip , but I am not thaat stupid ;-)
The wheel is already as close as it can be.

[GreyEyes]

If the boom is seated correctly, the problem often is the servo you are using.

Unfortunately there is no standard for the position of the output shaft.

The HK clone is a direct copy from Align, and the Align is designed for an Align servo. Align servos have the output shaft closer to the end of the case than a lot of other servos, so if the one you are using has the shaft closer to the center of the servo, the control rod will be short.

With some servos it is long enough but you don't have many threads left in the links

Your best bet is to make a carbon fiber one the length you need. It will be stiffer and you can do away the the rod gudes.

[amedv]

Originally Posted by GreyEyes

If the boom is seated correctly, the problem often is the servo you are using.

Unfortunately there is no standard for the position of the output shaft.

The HK clone is a direct copy from Align, and the Align is designed for an Align servo. Align servos have the output shaft closer to the end of the case than a lot of other servos, so if the one you are using has the shaft closer to the center of the servo, the control rod will be short.

With some servos it is long enough but you don't have many threads left in the links

Your best bet is to make a carbon fiber one the length you need. It will be stiffer and you can do away the the rod gudes.

I'll double check the boom, just in case. I see your point about the servo, but PoweHD HD-3688HB I used has the same dimentions (or very close) as DS520. The real difference is the mount. HK's mount looks more like aluminum upgrade from Align, though not the same.
Look like I'll have to make my own rod, which is OK. I was just wondering if it's a known issue.

[GeKu]

Before you go ang fly, change the mount to a plastic one. The HK mount is made with very soft alluminum and will snap on you and cause undue crash damage. If your just hovering around, you can probably get away with it but if you start doing things that apply more torque on the servo, it's gonna let go on you. Don't ask how I know.

[amedv]

Originally Posted by GeKu

Before you go ang fly, change the mount to a plastic one. The HK mount is made with very soft alluminum and will snap on you and cause undue crash damage. If your just hovering around, you can probably get away with it but if you start doing things that apply more torque on the servo, it's gonna let go on you. Don't ask how I know.

Thanks, man!

[fishfiend]

Originally Posted by amedv

I'll double check the boom, just in case. I see your point about the servo, but PoweHD HD-3688HB I used has the same dimentions (or very close) as DS520. The real difference is the mount. HK's mount looks more like aluminum upgrade from Align, though not the same.
Look like I'll have to make my own rod, which is OK. I was just wondering if it's a known issue.

I'm using the same servo, with the plastic mount on one of my 450pro clones, and I had exactly the same problem. On my other clone i'm using an Emax es9257 with anormal length carbon rod, but when I tried toinstall this on the other clone it fell short. What I did was cut a metal pushrod in half and glued it to a 3 mm carbon rod so the gap is in the middle to get the extra length. I then covered this in heatshrink and hey presto custom size pushrod.

Hope this helps

[amedv]

Originally Posted by fishfiend

I'm using the same servo, with the plastic mount on one of my 450pro clones, and I had exactly the same problem. On my other clone i'm using an Emax es9257 with anormal length carbon rod, but when I tried toinstall this on the other clone it fell short. What I did was cut a metal pushrod in half and glued it to a 3 mm carbon rod so the gap is in the middle to get the extra length. I then covered this in heatshrink and hey presto custom size pushrod.

Hope this helps

Thanks!
I've just made CF rod, cutting off the end from the original rod and glueing them into CF tube with JB Weld. Seems pretty strong.

Maidened that heli today, btw. It flies, but wags the tail. It does not seem the rudder problem, because it wags the tal up and down rather then side to side.
I wonder if it's my cyclic servos, or the head just being not made well enough...

It seems these Chinese knock-offs are just the waste of money.
Should've bought Align in the first place...