KDE PERFORMANCE TAIL CONTROL

[Redlight11]

Anybody installed the KDE upgraded tail on their Logo? If so, thoughts?

Link: KDE PERFORMANCE TAIL CONTROL

[dahld]

It's kinda all been said on RR's Mikado section. There is a post there about it already.

They use the same parts for a T-Rex 600 upgrade as well. See it on RCHR:

Bling is bling...

Edit: Sorry, I did what I hate when others do the same thing...and that is answering a post without reading it carefully. The original question was, "...Anybody installed..."

No, I haven't. So the only "fact" I can use in my answer, is that they DO use the same parts on their T-Rex upgrade.

(-: Dave

[Redlight11]

Originally Posted by dahld

It's kinda all been said on RR's Mikado section. There is a post there about it already.

They use the same parts for a T-Rex 600 upgrade as well. See it on RCHR:

Bling is bling...

Edit: Sorry, I did what I hate when others do the same thing...and that is answering a post without reading it carefully. The original question was, "...Anybody installed..."

No, I haven't. So the only "fact" I can use in my answer, is that they DO use the same parts on their T-Rex upgrade.

(-: Dave

No worries. I figured it was just "bling" and not an actual performance upgrade. Oh well. Thanks Dave.

[dahld]

Quote, "I figured it was just "bling" and not an actual performance upgrade."

You know, until a bunch of guys buy it and try it, we don't really know. It could very well BE a performance upgrade...but if so, an expensive one for sure. Then again, the small increase in performance combined with the added weight and added parts count might not be worth the $$$.

I'm sure it will sell some. Many guys do like to "individualize" their helis...and nothin' wrong with that KDE has made a good living apparently offering such "upgrades" for others helis. But then again, those other helis might REALLY NEED the help (-:

(-: Dave

[Nko15]

I think i will be one of those people that fly as intended.... its still 99% precent pilot, 1% heli.

[Redlight11]

Originally Posted by dahld

Quote, "I figured it was just "bling" and not an actual performance upgrade."

You know, until a bunch of guys buy it and try it, we don't really know. It could very well BE a performance upgrade...but if so, an expensive one for sure. Then again, the small increase in performance combined with the added weight and added parts count might not be worth the $$$.

I'm sure it will sell some. Many guys do like to "individualize" their helis...and nothin' wrong with that KDE has made a good living apparently offering such "upgrades" for others helis. But then again, those other helis might REALLY NEED the help (-:

(-: Dave

I will most certainly keep an eye out for reports of its performance. Im not looking to downgrade my bird but dang that silver sure is purty.

[vteknical]

Without having any experience with the KDE unit it's design on paper would appear to be an upgrade. Servos and brass slider may be happier as a result of the upgrade. Kind of like the counter bearing upgrade which may benefit some.

[DannyvG]

This is a downgrade for sure. Unless you dont mind extra friction between the slider and tail shaft.
There is more to it but just imagine with the slider in the left position in what direction will it move when there wasnt a tailshaft? The correct answer is towards the back of the heli. But the reason it doesnt move in that direction is because the tail shaft gives a opposing force. But this force also creates coulomb friction and that causes bad performance of the tail.
The friction is the highest with the slider to the left but it is there over the entire stroke.

So in theory this design is a lot worse then the original. You can also see in the video they chose the link lengths a bit strange. The last part of the movement to the left it will even almost lockup.

[SBL1]

Originally Posted by djamgils

This is a downgrade for sure. Unless you dont mind extra friction between the slider and tail shaft.
There is more to it but just imagine with the slider in the left position in what direction will it move when there wasnt a tailshaft? The correct answer is towards the back of the heli. But the reason it doesnt move in that direction is because the tail shaft gives a opposing force. But this force also creates coulomb friction and that causes bad performance of the tail.
The friction is the highest with the slider to the left but it is there over the entire stroke.

So in theory this design is a lot worse then the original. You can also see in the video they chose the link lengths a bit strange. The last part of the movement to the left it will even almost lockup.

I think you need to take another look at it. If the slider was to move to the left it would want to pull the slider forward, not back. That said remember the whole system is still rotating around a point so this friction you speak of creating 'bad performance' is a rather moot point. It would be no worse then the ball on the swash being driven up and down the mainshaft and in worse case remember the bearings in the slider are radial and are fully ready to take any radial loads thrown at them.

The idea of this part is to create a no comprise tail. The linkage setup KDE has chosen isnt the first time its been used, im pretty sure microheli made something similar a while back. That said this 'upgrade' elimiates the arc movement of a regular tail bellcrank on the pitch slider. This gives two main advantages, firstly it enables everything to be secured with a bearing race, promoting smoother movement under load and secondly, no slop

[DannyvG]

Originally Posted by SlowBarless

I think you need to take another look at it. If the slider was to move to the left it would want to pull the slider forward, not back.

Doesnt matter in what direction you are moving, the point is that servo forces contribute to friction forces between slider and tailshaft and it is the worst with the slider to the left.
Normally the fixed pivot point takes those loads but here you have a extra link with pivots so it can only take those forces when the extra link is extended fully in the direction of the tail boom either front or back. So in stead of the forces being taken by the fixed pivot it now is done by the slider on the tailshaft.

Originally Posted by SlowBarless

That said remember the whole system is still rotating around a point so this friction you speak of creating 'bad performance' is a rather moot point. It would be no worse then the ball on the swash being driven up and down the mainshaft and in worse case remember the bearings in the slider are radial and are fully ready to take any radial loads thrown at them.

For a heading hold control loop it is bad news. First thing everybody says when you complain about a wag is how smooth the tail moves.
The extra pivot link and the fact that the fork is attached to the slider is what causes the extra friction.

Just make a free body diagram of the original and the KDE and you will see what I mean.

[SBL1]

Originally Posted by djamgils

Just make a free body diagram of the original and the KDE and you will see what I mean.

I do understand what you mean and completely agree with you. Just understand that every design has compromises and this is no different. This design addresses issues that the orginal tail had however it obviously carries flaws of its own. Who knows if it will improve the tail response or degrade it, they only way you will know is by testing it. My experience will KDE tail upgrades is that they are better off left alone though.

Keen to hear from soneone whos used it.

[GimpyGolden]

I have same setup on my Mini Titan.
While it works well(when shaft is oil'd) and has zero slop I will not be putting Trex bling on my Logo.

[DannyvG]

You have a picture of that tail, I am very interested in how it looks.

@slowbarless, I get your point now.
I am just wondering if they are aiming at correcting a problem that doesnt exist and create another problem in the process.
You only encounter play when going through the negative pitch, above and below the thrust force will take out the play.

Who actually has problems with the logo tail? And what are the problems?

[GimpyGolden]

Will grab a pic later. It is standard setup on Mini-Titan if you want to DL manual or cruise pic thread.
https://www.helifreak.com/showthread.php?t=29494

[DannyvG]

I see, that surprises me. But as you pointed out, oiling the shaft improves performance so it just shows there is to much friction.

Still seems like a downgrade to me. Wont be spending 90USD to try it.

[GimpyGolden]

Yup for sure the MT needs oil everyday out which would confirm there is some friction there. No slop though and it works.

I'm sure they're setup works well but I see no need for improvement over stock when properly setup and maintained.