Carbon Fiber Tail Boom Cover

[AdrianStockton3]

Assistance as well as support is need, any given will be much appreciated!

I have installed a carbon fiber custom tail boom cover on my Logo 800 Xxtreme. While inspecting the alignment of everything related to the install, I noticed that the tail rotor push rod is slightly flexed at the push rod guide bracket. I have disassembled and reassembled, loosened and adjusted everything two times in an attempt to correct this issue.

Note: Prior to the custom boom cover install the Logo 800’s tail rotor push rod was straight and any flex was absent as it sat idle and even within its mechanical movement.

After spending a good portion of last night, disassembling and making adjustments to include the angle of the guide bracket and reassembling. The rod still exhibits flex but reduced. However, during mechanical movement more flex is incurred. I also noticed the rear ball link rest really close to the suffice floor of the custom boom. During full right and left rotor input movement it slightly rubs.

I have searched different forms dealing with the 800 Xxtreme, as well as forms consistent with other models that have a custom carbon fiber boom option. To include those that comes with a carbon fiber boom as part of their engineered design. The only thing I have come across in my quest to resolve this issue is the SAB Goblin 570. In which the push rod in this model is flexed by design to alleviate vibration in this area. However, I do not think this is applicable with the 800 Xxtreme. This thought was validated by a Mikado USA tech with whom I have spoken. He has indicated that any flex should be absent of the tail rotor push rod. He has also requested pictures to be sent, in which I am in the process of doing.

I have taken the liberty to post those same pictures here so that others may view. To hopefully give a better insight of what I have attempted to explain. I am reaching out to those that may be able to assist me in resolving this issue. Again, any assistance and support is greatly appreciated.





Note: The pictures show the severity of the flex and the reduced flex. There are two zoomed shots of those same photos. There is also a picture showing the closeness of the ball link.

[rcmarty]

I'd think that Mikado usa should know about this bowing.

It's a logo 600 tail boom clamp.

I'm getting about 110-140 flights before the rod has reduced in diameter to make me nervious.

Now with the support it doesn't rub hard (and harder with servo throw)

https://www.helifreak.com/showthread.php?t=645465

Martin

[AdrianStockton3]

Thank you for such a quick reply!

I am also most grateful for the link as well, I will explore some of the suggestions made. Am I, to understand that I should be okay to fly for a little while with this flex as long as everything else is in order? I know that nothing is full proof and anything can happen so I'm not taking any suggestion as infallible. I'm seeking to give my mind some rest and peace. Knowing that others have experienced this issue and are flying with it credits me that.

I have only had the Logo 800 about 8 months with around 10 flights. It is intimidating to fly without any known problems or issues. Having it for such a short time and reflecting on its expense coupled with the intimidation factor and a known problem brings the emotionally intensity and unrest to toxic levels.

I will add some lubricant to the rod as I read you did in the mean time, until I am able to find a more permanent solution.

[gtrsteele]

I am also in the process of installing the tail boom cover. What a pain in the kester. The manual for disassembly and reassembly is not very well written. Since the screws that hold the frame spacers have to be removed my questions is how do I get the frame spacer in the middle back in (see pic)? I don't have long flexible fingers. Argh


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[AdrianStockton3]

YES! The installation of this boom is a pain.

However, the spacers have a small hole in the middle that goes all the way through. I used a pin size dowel held with hemostats to insert in the whole for control. Note: A pin size nail will also work. Needle nose pliers will also work to hold what ever you chose to put in that hole, but I chose to use hemostats because it gives a better grip. Once the carbon fiber boom is installed. The areas in which the spacers have to be reinstalled can be accessed through the side openings of the boom, using the same method.

Laying the Logo 800 on its side also aided in holding the brackets that secure the original boom in place from dropping down due to the removal of the screws. Once the screws from one side was removed. I tightly held the frame to the brackets in that area with my hand and slowly rolled the Logo 800 over to the other side, so that I could remove those screws.

While the Logo 800 was still on its side, I installed the carbon fiber boom by sliding it over the original boom. Then using the same method to re-secure those screws. Once the bracket screws are back in place, the 800 can be stood upright on it skids to reinstall the spacers.

[rcmarty]

Originally Posted by AdrianStockton3

Thank you for such a quick reply!
......

I have only had the Logo 800 about 8 months with around 10 flights. It is intimidating to fly without any known problems or issues. Having it for such a short time and reflecting on its expense coupled with the intimidation factor and a known problem brings the emotionally intensity and unrest to toxic levels.

I will add some lubricant to the rod as I read you did in the mean time, until I am able to find a more permanent solution.

I recommend the dry fluids gear lube for the gears in the front and back.

I stripped/melted a set of gears on my 700 at 130ish flights and 800 at 120ish.
Tried to find out why but it 'doesn't happen' (visa begs to differ ), and a suggestion was made to use dry fluids on the gears.

So far I have over the 130ish flights on the 700 and gears are still good (knock on wood)

Martin

https://www.helifreak.com/showthread...t=melted+gears

https://www.helifreak.com/showthread...51#post6052651

[AdrianStockton3]

Have anyone had to modify the carbon fiber tail boom cover to prevent the rear ball link from contacting it?

[Chippie13]

Hi I have both the 800 and the 570;-) I bought the 570 second hand so I could get back in the air asap when my 800 when face in.

The guy I bought the 570 from said he was not happy with tail behavior on the 570 but when I flew it I loved it. His style is very aggressive 3d as he is a extremely good pilot and alas I am not. Long story short my skills have picked up a little and I started noticing tail issues and so my investigation started and I came across the 570 bow in the push rod.

It is much more severe than what is shown in your 800 pictures. I have taken a picture to try show you. It was not the cause of tail problems on the 570 as I found the problem to be a clamping mechanism which was 0.01mm to small and actually clamping onto the push rod instead of holding it in place. As soon as I ever so slightly enlarged it to make the push rod slide freely the tail behaved amazing. I had a look at my 800 and I have bowing to although barely any side to side there is a little up and down bowing.

I do not have the tail boom cover so I played around with the push rod guide easily by moving it on the boom to see if I could get rid of the bowing. Here is my findings:

You cannot get rid of the up and down bowing neither the side to side.
The distance from the outside of the tail boom to the center of the push rod guide is +-12mm.
My servo horn in the 90 straight up position is almost exactly the same 12mm from the boom outer edge.
The ball link at the tail end at 90 is almost exactly 12mm as well.
So when the push rod is in neutral position my rod is perfect with my guide installed the same as yours, which is slightly leaning to the right side when viewed from the rear. This removes the left right bowing in neutral and you should see almost no up and down bowing either.
The servo horn ball link has a up and down motion when it moves to push and pull the rod....servos move in a circle no getting rid of that.
The tail end ball link also pivots around a bolt so has the same circular motion and although the main motion is push and pull it will have a left right part to it.

Hence in summary and my limited design capabilities you cannot get rid of the bowing unless you design a different mechanism to guide that push rod and move slightly up and down and left to right when the push rod tries to bow. But in my mind that is exactly the reason it is there as it is supposed to guide the push rod and not move.

I hope this helps and please this is just my opinion based on my findings so feel free to question it

The 800 picture is to show how much space there is for the push rod to move freely in the guide and the 570 picture I added red arrows pointing to the push rod for clarity. Please note that both push rods are in the neutral position. The 570 push rod actually becomes more straight towards the edges of travel and bows more towards the neutral position.

[gtrsteele]

Originally Posted by AdrianStockton3

YES! The installation of this boom is a pain.

However, the spacers have a small hole in the middle that goes all the way through. I used a pin size dowel held with hemostats to insert in the whole for control. Note: A pin size nail will also work. Needle nose pliers will also work to hold what ever you chose to put in that hole, but I chose to use hemostats because it gives a better grip. Once the carbon fiber boom is installed. The areas in which the spacers have to be reinstalled can be accessed through the side openings of the boom, using the same method.

Laying the Logo 800 on its side also aided in holding the brackets that secure the original boom in place from dropping down due to the removal of the screws. Once the screws from one side was removed. I tightly held the frame to the brackets in that area with my hand and slowly rolled the Logo 800 over to the other side, so that I could remove those screws.

While the Logo 800 was still on its side, I installed the carbon fiber boom by sliding it over the original boom. Then using the same method to re-secure those screws. Once the bracket screws are back in place, the 800 can be stood upright on it skids to reinstall the spacers.

The hemostat worked like a champ. Thx!


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[gtrsteele]

I now have three problems:
1) The boom is in the way of the canopy closing. What's the work around for this?
2) What do I use for a blade holder now?
3) Where do I put my DSMX sats now?

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[Chippie13]

Hi @gtrsteele

I have suggestion for your canopy mounting. See attached photos. I used the extra tail servo metal plates that was included in the kit as you only use one set depending on your servos.

I then slightly bent them with a vice grip and the floor but I suppose a bench clamp if available will do a better job.

The canopy mounts like a dream with the quick releases I installed and it sits higher and much better than my old canopy did. I included a photo to show how high it is seated above tail boom which might help with yours.

Have a look at the SAB Goblin 770 blade holders as I am sure without too much if any modification they might fit. Please note I only have a 570 but looking at the blade holders and how they are cut for the tail I guess it will fit.

Satellites you are on your own

[gtrsteele]

Originally Posted by Chippie13

Hi @gtrsteele

I have suggestion for your canopy mounting. See attached photos. I used the extra tail servo metal plates that was included in the kit as you only use one set depending on your servos.

I then slightly bent them with a vice grip and the floor but I suppose a bench clamp if available will do a better job.

The canopy mounts like a dream with the quick releases I installed and it sits higher and much better than my old canopy did. I included a photo to show how high it is seated above tail boom which might help with yours.

Have a look at the SAB Goblin 770 blade holders as I am sure without too much if any modification they might fit. Please note I only have a 570 but looking at the blade holders and how they are cut for the tail I guess it will fit.

Satellites you are on your own

I got my kit second hand so I don't have those servo mounts. I found them at mikadousa so I'll order some. I also found quick release canopy mounts for the 700 on their site. Will they work on the 800?
I have a 770 as well and the blade holder does work, but need a little morning. I'll order another one. Thanks!


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[Chippie13]

@gtrsteele I had a look at the mounts on the Mikado site and if it is the ones as here https://shop.mikadousa.com/L7QRCM-Lo...nts_p_920.html I don't know as they are listed as 32.26mm and the ones I have are 27mm. Again this is a "bend till it works" modification so maybe they will.

The specific ones I used are shown here http://www.rcbooya.com/align-700-series.html under the "700 Nitro REAR Quick Release Canopy Mounts". They are listed as 27.12mm so clearly my measurement was off but then again I used a ruler

[gtrsteele]

I think you have to use the Align mounts since they are shorter. The Mikados are a "stock" length and I can see how they would be too long. Thanks again for the info.


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[Chippie13]

Pleasure I hope it helps with getting a proper fit on that tail boom cover!

[AdrianStockton3]

gtrsteele,
After you installed your boom cover does the rear ball links contact the inside suffice of the boom as shown in the last picture at the beginning of this thread?

[gtrsteele]

Originally Posted by AdrianStockton3

gtrsteele,
After you installed your boom cover does the rear ball links contact the inside suffice of the boom as shown in the last picture at the beginning of this thread?

Only at 100% rudder input nose left, but I'm at a mechanical bind at that point and that's when part of the rod touches. I'm mean it barely touches. It's a non issues for me.



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[AdrianStockton3]

Wow!!! yours sits much high, I have contact at both full right and left rudder. At full left rudder I can hear the servo bind.

[gtrsteele]

Originally Posted by AdrianStockton3

Wow!!! yours sits much high, I have contact at both full right and left rudder. At full left rudder I can hear the servo bind.

Is it bad that mine sits high?


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[AdrianStockton3]

It was bad language on my part and not very clear. I was referring to your push rod and ball links. They ride higher than mine not your boom. Yours looks as if it sits fine. It's bad that mine sits low. To measure how hard the contact is, I placed a piece of stripped paper where the ball links contact the boom at full right and left rudder. The contact at full right rudder is not as hard as it is at full left rudder. At full right rudder the paper removes easily with just a little bit of pinch, that I can live with. At full left rudder it is a very hard pinch and the paper slightly rips before it is fully removed. Also, there are times at left rudder that the ball link gets stuck on the edge of the boom when trying to return to neutral or center.

This has baffled me and I have gotten frustrated having to remove and reinstall so often in an attempt to work this out. I've even broken a screw off in the tail boom chassis gear box making adjustments.

NOTE: Breaking a screw off is VERY!, VERY!, VERY!, BAD. The hex screws are made of harden steel and they DO NOT DRILL OUT. The only way to remove a screw and save the part is to use a EMI or Mill machine, neither of which I have. I do however have access to a milling machine but I've chosen to take the low road and ordered the part.

That being said, I am encouraged to see that your installation is going or has gone well. I know that I will get there. Eddi E. from aus.g tagged me back on the Mikado support form suggesting that the boom may need to be modified.

He says, "If the custom boom cover touches moving parts, it simply does not fit perfectly. So sand or dremel off enough to make it fit. That could matter technically, the carbon could else damage the bell crank."

Kind regards

Eddi

Born to fly ...
forced to work.