Backwards blade grips. Leading edge vs trailing edge control

[Heli Paramedic]

Hi All,

Just noticed on my new HDX500 that the main blade grips were factory setup with trailing edge control. The seesaw is flipped along with the main blade grips so the links line up reasonably well. I have had my heli flying quite well with this backwards setup. I was wondering if there is any advantage/disadvantage in setting up my head as per the manual with leading edge control on the main blade grips.

Thanks.

[aussiemick]

They are supposed to Trailing Edge control. (Similar layout to the Trex 450)

In the 3DX version it is Leading Edge control (Same as the Lepton)

Mick

[Heli Paramedic]

Thanks Aussiemick,

As I said my heli flies fine with trailing edge control, although every photo I have seen of the HDX500 with the same style of head as the trex shows leading edge control. The pictures on takeoff and lands website as well as helidirect show leading edge control also. Would there be any benefit in reversing my blade grips and seesaw? Are all the pictures on these websites showing the head set up incorrectly?

Thanks.

[aussiemick]

Thanks Aussiemick,

As I said my heli flies fine with trailing edge control, although every photo I have seen of the HDX500 with the same style of head as the trex shows leading edge control. The pictures on takeoff and lands website as well as helidirect show leading edge control also. Would there be any benefit in reversing my blade grips and seesaw? Are all the pictures on these websites showing the head set up incorrectly?

Thanks.

The only thing I didnt do to my original HDX head to get better cyclic response was try out Leading edge control. I now have the 3DX head.

First 2 and last photos taken from takeoffandland

First up a 3DX head
http://takeoffandland.com.au/images/3dX500_headb.jpg (http://javascript<b></b>:;)
Then a HDX SA head
http://www.helidirect.com/images/helicopter_kits/SAH-head.jpg

and from Helidirects ebayshop
http://www.helidirect.com/banner/HDX500-head.jpg
and if you look at the link length picture then you will see right at the top that the far blade grip is trailing edge control.
http://takeoffandland.com.au/images/rod.jpg (http://javascript<b></b>:;)


Mick

[Heli Paramedic]

Hi Mick,

You are right. All the photos you show have trailing edge control for the trex style head. I am still confused though as the instruction manual (if you can call it that) that came with my HDX500 shows a trex style head with leading edge control. Also the photo below from helidirect shows the same. I think I'll change mine to leading edge control and see how it flies. But basically what I'm asking is there any benefit or disadvantage to leading edge vs trailing edge control. Not just for the HDX 500 but for any heli? Thanks for taking the time to reply Mick. http://www.helidirect.com/images/UGLHS.jpg

[aussiemick]

From what I gather:

Leading edge control gives Quicker Cyclic acceleration (twitchier) not faster pitch or roll rate.

You should only have to reverse the Tx swash amount in collective not cyclic.

Please report back how it goes if you do decide to flip the grip!

MIck

[Heli Paramedic]

No worries Mick. I'll let you know. It may take some time though as I'm grounded for the moment due to a faulty AR7000 receiver that came with my kit. I'm waiting on a replacement from Takeoffandland. Hopefully should have the new reeceiver in the next few days or next week at the lastest.

[kantut]

the tail on my hdx5..it is the leading edge, is there a rule for this also?
i'm thinking of trailling edge, kinda protects the grip in a crash??

sorry for starting another thread but i think it's the same subject..

[aussiemick]

the tail on my hdx5..it is the leading edge, is there a rule for this also?
i'm thinking of trailling edge, kinda protects the grip in a crash??

sorry for starting another thread but i think it's the same subject..



The tail blade grips should be leading edge control. Other wise the push rod would be under permanent compression, and as far as I know that would be a bad thing, unless you have a VERY stiff Push rod.

MIck

[moyesboy]

I attempt to explain what changes the handling when you reverse the grip from TE to LE
When you move the spindle in the dampers the blades grips move up and down. The spindle tilts about the centre, but the grip ball joints are off the centreline. so when you lift one blade with trailing edge control the pitch increases. with leading edge control the pitch decreases. One is a stabilizing effect, the other is the opposite.
On some helis you can adjust the offset of the blade grip ball joint to change the effect.

[webb1john]

Hello all. I did the swap to leading edge on my HDX 450. It made cyclic input much more smooth, stable and just plain easer to fly. The draw back, but I had to reduce my cyclic input due to binding of the linkages. This made it was slower to flip and roll.

[Heli Paramedic]

the tail on my hdx5..it is the leading edge, is there a rule for this also?
i'm thinking of trailling edge, kinda protects the grip in a crash??

sorry for starting another thread but i think it's the same subject..
kantut,

My HDX500 came from the factory setup with trailing edge control for the tail blade grips. Seems to fly fine this way. Tail holds really well (GY401 & Futaba 9254).

[Hotwings]

I have two trex 600e's and one is leading edge and one is trailing edge, can't tell any difference in them. I made a mistake and built the first one leading edge as i copied the program from a tiger 50 that i had flipped the grips. like i said i can't tell any difference at all on the Trex. Ron

[Heli Paramedic]

I have two trex 600e's and one is leading edge and one is trailing edge, can't tell any difference in them. I made a mistake and built the first one leading edge as i copied the program from a tiger 50 that i had flipped the grips. like i said i can't tell any difference at all on the Trex. Ron
Hi Hotwings,

Interesting. Are you talking about the main or tail grips or both on your Trex 600e?

[Heli Paramedic]

Hi All,

I changing my HDX500 with the Trex style head to leading edge control just like the following photo from the helidirect website. I discovered that this does not work. In order to do this I had to flip the seeswas also. As a result I encountered 2 main problems:

1. In order to get the blades moving the correct way I had to reverse my swash mixing for pitch. This means that to get +ve pitch the swash moves down and vice versa. To weird for my liking

2. The link that goes from the swash to the mixing arms binds severly on the bolt that holds the washout arm to the slide block.

Therefore my conclusion is any photos that show the Trex style head with leading edge control are incorrect as it simply does not work.

As it is a Trex style head, just set it up as so and you won't go wrong.

Does everyone agree with this??????????
http://www.helidirect.com/images/UGLHS.jpg

[Hotwings]

My trex heads are one leading edge and one trailing edge with no binding whatsoever. these are main grips only, have never flipped the tail grips. Ron

[Rotorworkz]

The HDX500 Head design is intended to have trailing edge main blade Grips