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-   -   Pull-Pull for rudder in 2M planes - recommendations. (https://www.rcuniverse.com/forum/electric-pattern-aircraft-385/11646311-pull-pull-rudder-2m-planes-recommendations.html)

bem 04-02-2018 01:45 AM

Pull-Pull for rudder in 2M planes - recommendations.
 
Hi,
I have never used pull-pull with wires for rudder in my F3A planes.
But now I will change on my Galactika plane to pull-pull since I need to move the rudder servo to the front for center of gravity reasions.
I will use lighter LiPo flight batteries in my Galactika this season so that is why I need to get my plane lighter in the tail, rudder servo
need to be moved to the front.

If You have any advice to give me (and others) that do pull-pull for the first time in a 2M F3A model please post in this thread.
I'm particular intgerested in proven suitable wire and sutable ball-links solutions. As light as possblle but without compromising needed strength.
If You know some sourses to buy the needed hardware, that is welcome also.
I have seen that Secraft has pul-pull solutions but it might be a little too beefy and heavy for our use, and Little heavy also.
I found an image (see last iimage below) on internet with a pull-pull solution that might be suitable but I do not know what brand it is.

Some photos below of my Galactika present rudder servo installation. Note that I have already good exit holes for wires in the tail, so I will use the holes that has been
used for the old rudder tubes.
It is quite much weight (plywood tray, servo Futaba BLS171SV 48 gram/1.7 oz, S.BUS2 hub+plate) in the tail on my Galactika.
I would not be surprised it is total 60 gram that will be taken out of the tail weight.
I will try to mount the rudder servo in front as much forward as it can be mounted.
The flight battery I use today weight about 1160 gram (Hacker Top Fuel Eco-X 5000 mAh).
New flight battery will probably be Hacker TopFuel ECO-X 4600 mAh Competition F3A 2017, 970 gram.
My goal is to get my Galactika close to 200 gram lighter.
/Bo

https://cimg1.ibsrv.net/gimg/www.rcu...8360ab87ea.jpg
Old carbon tubes to rudder.


https://cimg0.ibsrv.net/gimg/www.rcu...d84a90219c.jpg
Present Futaba BLS171SV servo and servo arm in tail of my Galactika.


https://cimg2.ibsrv.net/gimg/www.rcu...c08fbf4d20.jpg
Present S.BUS2 hub in tail of my Galactika.


https://cimg3.ibsrv.net/gimg/www.rcu...4a1c560c7d.jpg
Rudder servo will me moved to new location somewhere between the wing adjusters.

https://cimg3.ibsrv.net/gimg/www.rcu...f0329219d3.jpg
Exemple of pull-pull hardware that might be suitable - what brand ?

kenh3497 04-02-2018 07:03 AM

There are quite a few cable pull/pull systems out there. I build my own using cable fishing leader material and the crimps that go along with the cable. Any good fishing outlet should have that on hand. I use regular clevises for the connection to the rudder. Here are a couple DuBro systems.

https://www.dubro.com/collections/pu...ll-pull-system
https://www.dubro.com/collections/pu...ll-pull-system

Ken

kdunlap 04-02-2018 01:07 PM

Use these https://www.f3aunlimited.com/secraft-wire-tensioner-red and good wire from the dubro system and it will be problem free.

ltc 04-02-2018 03:24 PM

1 Attachment(s)
Hello Bo,
In your last picture, that control horn is from Bryan Hebert (bottom of page)
CK Aero | Accessories

Here is an article on how to locate the fuselage exits for the pull pull cables
Attachment 2259737

FWIW, here is an article on pull pull geometries...
Pull-Pull Wire Explanation

PeterP 04-02-2018 09:56 PM

I would use all the existing hardware you are currently using and would replace the pushrods with the following

https://www.towerhobbies.com/cgi-bin...?&I=LXFV31&P=7

Go you your local fishing shop and purchase nylon coated stainless steel fishing wire 15-20kg.

bem 04-03-2018 03:47 AM

Hi,
Thanks guys, some good suggestions.
I wished I know where to buy these below (not the control horn, just the pull-pull linkage), that I posted a photo of in my first post.
I kind of like those. I respost the photo here again, maybe somone know a supplier.
/Bo

https://cimg2.ibsrv.net/gimg/www.rcu...f897002dfc.jpg

RCFlyerDan 04-03-2018 03:54 AM

Another recommendation; after you get your wire, I have even used coated fishing cable, take the wire and hang 5-10# weight with the wire and tie the ends to something secure for it to hang. Hang for about a week to let it stretch. Then install the cable. If not, the cable will stretch with usage and you will have to adjust for awhile as it stretches in the plane.

nonstoprc 04-03-2018 05:00 AM

Hi Ben,

You may get the following parts for the pull-pull linkage pictured in your post.

Rigging couples: https://www.towerhobbies.com/cgi-bin...?&I=LXE073&P=M
Ball-bearing adjusters: https://www.f3aunlimited.com/ball-be...ter-2mm-fh5001
Cables: https://www.f3aunlimited.com/secraft...cable-8mm-1-32

MK used to offer a super light pull-pull system for 2M but I could not find it from Central Hobbies' website anymore.

PeterP 04-03-2018 05:20 AM

Hi Bem,

I would personally avoid any of the types of couplers you mentioned. The sharp edges will result in cable break as the edges will eventually cut through the cable. The steel versions are worse still and they always seem to break at the most inconvenient time.

The Sullivan type I mentioned in my previous post are gentle on the cable because of the rounded shape resulting in very little cable wear over time. They look neat when done properly.

Here is a picture of my setup.
https://cimg6.ibsrv.net/gimg/www.rcu...9ffd89d71.jpeg

nonstoprc 04-03-2018 05:26 AM

The copper couplers probably are not sharp as the steel version and one can easily remove the sharp edges (if any) with a Dremel tool.

PeterP 04-03-2018 05:34 AM

They are not copper - Brass. Brass wears!. I stand by my advice that the Sullivan type are the best option available because of the reasons mentioned and cheap.

nonstoprc 04-03-2018 05:50 AM

I have never experienced any cables being cut incident with the following steel coupler setup. The plane is with me for 5 seasons.

Personally, I think the choice of the cable probably matters and have great success with Dubro and F3Aunlimited cables.

https://cimg0.ibsrv.net/gimg/www.rcu...7d868e3e0.jpeg

PeterP 04-03-2018 06:10 AM

You Win ;-)

nonstoprc 04-03-2018 06:15 AM

You mentioned a good point though one needs to check the cables carefully :-).

OhD 04-03-2018 09:40 AM


Originally Posted by RCFlyerDan (Post 12418738)
Another recommendation; after you get your wire, I have even used coated fishing cable, take the wire and hang 5-10# weight with the wire and tie the ends to something secure for it to hang. Hang for about a week to let it stretch. Then install the cable. If not, the cable will stretch with usage and you will have to adjust for awhile as it stretches in the plane.

Use control line wire. Doesn't stretch.

Jim O

shannah 04-03-2018 01:08 PM

Hi Jim,

Good idea, what size control line wire do you use?

OhD 04-03-2018 02:38 PM


Originally Posted by shannah (Post 12418917)
Hi Jim,

Good idea, what size control line wire do you use?

Hi Steve,

I was afraid someone would ask. I can't find the spool I bought about 100 years ago when Tony Frackowiak put me on to it, but my micrometer says it is .020 inch diameter. I use brass rod end couplers into conventional clevises. I fold the control line wire over and push it into the coupler and then fill it with solder. Never had one pull out. You can see by the dust I haven't flown this plane in a long time.https://cimg1.ibsrv.net/gimg/www.rcu...ce82a74c58.jpg

bem 04-04-2018 12:00 AM

Hi,
Great advice so far, I'm sure there is more on this topic so please add more if You have.
I checked Brodak control line wire (cable) and they have these wire diameter to choose from.
They do not have any weight listed.
What diameter do You recommend?

http://brodak.com/control-line-parts...lines.html?p=1

https://cimg9.ibsrv.net/gimg/www.rcu...6bb6526f95.jpg

I have noticed some cables (not Brodak) for pull-pull are coated - what advantage might that be for our purpuse?
Just some extra weight in our case? If stainless wire, like Brodaks, it will be no corrosion/rust for our usage so need for coating because of that.

/Bo

bem 04-04-2018 02:29 AM

Hi,
After some searching on the internet I have found out that the wire tensioner I have been trying to find out who makes it is used in some Hangar 9 ARF's. But I can not find it as spare part at Hangar 9.
I will dig some more with help of Google.
/Bo

https://cimg8.ibsrv.net/gimg/www.rcu...06de53f963.jpg https://cimg9.ibsrv.net/gimg/www.rcu...5f5db29bc7.jpg

kenh3497 04-05-2018 05:14 AM

I'm not 100% sure but a 40ish size control line plane has /is supposed to be tested for about 50ish pounds of pull to be save. I'm sure there is that info on the AMA sight in the control line competition rules.

Ken

wingster 04-05-2018 01:20 PM

"I have noticed some cables (not Brodak) for pull-pull are coated - what advantage might that be for our purpuse?"

You can wrap the ends a couple of times and use a match to melt the coating. Then use a piece of shrink tubing to dress up the joint. Works Great!

Coating also prevents metal to metal contact when using crossed wires.

speedracerntrixie 04-05-2018 04:09 PM

The best I have found for both weight and strength is using the Sullivan 2-56 eye screw and nylon coated Kevlar. The Kevlar is sold by an outfit in Ca called Aerospace Composites Products. I use 1/8" K&S aluminum tube cut into 3/8" sections as the crimp. Crimp add a drop of medium CA and then heat shrink. Bullet proof, light and won't stretch.

bem 04-05-2018 10:00 PM

Hi,
I ordered the Sullivan kevlar pull-pull that should be here in a few days.

S521 – 12′ of 100 lb Strength Kevlar. Eyebolts, crimp tubes, Gold-N-Clevises, and other hardware included, 2-56
Pull-Pull Systems ? Sullivan

I might need to get the 4-40 (2.9 mm) instead of the 2-56 (2.2 mm) eyebolts if I want to use my existing clevis.

/Bo

speedracerntrixie 04-06-2018 06:19 AM

Bo, I have used the Sullivan Kevlar set up as well on a 40% Extra. The only issue I saw is that it has no coating and it either has to not rub on anything or in my case, I put a sleeve of heat shrink tube where it exited the fuselage.

grotto2 04-07-2018 04:10 PM

https://cimg0.ibsrv.net/gimg/www.rcu...66599bf6e.jpeg

This is a horn developed by the late Sam Turner. I've used it for many years. A dowel is drilled and tapped for 4-40 and epoxyed into a hole cut with a piece of serrated brass tube. It can be slightly adjusted for centering by bending the inserted 4-40 rod and throw can be adjusted by running the aileron fitting along the rod's length.

drac1 04-08-2018 02:28 PM

This is my setup. 60lb nylon coated stainless steel fishing trace, The ball links are MK, but there are others out there that are OK. I would avoid the rigging couplers though, Sullivan eye bolts are best.

https://cimg0.ibsrv.net/gimg/www.rcu...e563e72512.jpg
https://cimg1.ibsrv.net/gimg/www.rcu...1360c81afc.jpg

speedracerntrixie 04-22-2018 06:10 AM

https://cimg0.ibsrv.net/gimg/www.rcu...6d2bfaa8fc.jpg
https://cimg1.ibsrv.net/gimg/www.rcu...781176bf53.jpg
Can't get much lighter then this. Control horn is CF tube with CF rod inside. Dubro aileron connector is glued onto CF rod with thin CA. Cable is nylon coated Kevlar, crimped with aluminum tube and thin CA for insurance. Shrink tube over crimp cleans it up a bit. Adjustment at servo only but Kevlar won't stretch so after initial tightening of the cables it never needs adjusting again.

bem 04-30-2018 02:47 PM

Hi all,
First thanks for all Your photos and descriptions of Pull-Pull solutions in various planes.
I got all the hardware needed some days ago for my Pull-Pull solution for my Galactika. I have finnished it now.
I use the Sullivan Pull-Pull #521 with Aramid fiber lines and Sullivan #549 4-40 steel eyebolts. These eyebolts fitted in my existing blue links (original Oxai links shipped with my Galactika).
In my experience now I think installing Pull-Pull system is not that easy. It was rather much work on my Galactika. First I checked carefully present CG with Xicoy Balance and Weight meter, with old setup with rudderservo in the tail and the 5000 mAh LiPo (Hacker Eco-X 20C 5000 mAh) I used before. Then I removed servo in the tail, Futaba BLS171 SV, the servo mounting plywood, and the S.BUS hub mounting plate I had in the tail.
The rudder servo in the tail has a weight of 53 gram, the plywood mounting removed 9 gram, total 62 gram. I mounted the S-BUS hub with contact glue instead to side of fuselage inside tail and saved some grams there also since I do not use the mounting plate for the S.BUS hub I had before.
Then I placed the plane on the Xicoy Balance and Weight meter again, mounted the new lighter Hacker Eco-X 4600 mAh 20C F3A Edition LiPo, and rudder servo just behind the wing adjusters (temporarily) in the front of fuselage. I use 8x8 mm square carbon tubes as mounting for the rudder servo in the front of fuselage and 4 round glass-foam laminate holders I made glued to fuselage sides.
After some adjustments back-forward of the LiPo battery on the tray in the fuselage It was nice to see that I was able to have the new lighter LiPo batteri in the middle of it's tray in the plane and have same CG as before, so I glued the carbon tubes f
or the rudder servo permanently in fuselage.

The Sullivan aramid fiber kevlar lines has a breaking strength of 100 lbs, is nonmetallic and will not cause RFI, is lighter then steel, will not stretch. To cut aramid line one need very sharp scissors. The Sulllivan #521 Pull-Pull contain 12 ft (3.65 meter) aramid line.

The reason behind going through the trouble changing from rudder servo in the tail with short rods, to the rudder to servo in front of fuselage and Pull-Pull system to rudder was the desire to get my Galactika lighter. Now my Galactika is down to a take off weight including LiPo of 4880 gram, and lighter then that is hard to get with my present equipment in the plane.

So all in all I think the job changing to Pull-Pull system is worth it. We will see if the change in weight, in my case, will have any noticeable effect on flight characteristics. Maybe the plane will climb little easier in vertical maneouvres, and mabe the lighter tail (by 62 gram) can have some nice impact also for example on stall turns, in general it is no good to have extra weight in the tail since the goal is to have as much mass centered close to center of gravity for good flight characteristics, as with most planes.

Now I have 5 new LiPo packs to assemble (changing and solder to bullet connector, and mount cardboard on underside, little boring job but must be done).
The weather seems not to be good in near future here so I will have to wait some for flights with the new Pull-Pull system.

I hope this thread can be of interest to others when doing Pull-Pull for rudder in a plane.

/Bo

https://cimg9.ibsrv.net/gimg/www.rcu...e53c7fae9d.jpg
Things needed for the Pull-Pull system: Sulllivan #521+549, 8x8 mm square carbon tube, shrink tube and some light glass-foam laminate for round mounting points on fuselage sides for the carbon tubes.

https://cimg8.ibsrv.net/gimg/www.rcu...91780e85ad.jpg
The aramid fiber line, shrink tube, copper crimp tube and eyebolt. I made an extra loop throught the copper tube.

https://cimg2.ibsrv.net/gimg/www.rcu...f3599e92a7.jpg
After copper tube has been crimped.

https://cimg5.ibsrv.net/gimg/www.rcu...cfc2eea745.jpg
I used a crimp tool (for electric contacts) with the hole marked with 18-22 (AWG No.).

https://cimg1.ibsrv.net/gimg/www.rcu...16c15c0822.jpg
Shrink tube mounted and heated, all finished.

https://cimg3.ibsrv.net/gimg/www.rcu...16caabc87b.jpg
Tail servo removed and S.BUS hub relocated and mounted on fuselage side. Dental floss used to secure the servo connector in the S.BUS hub connector. Sullivan red tubes glued as exit guides (glued with epoxy-micro ballons paste).

https://cimg0.ibsrv.net/gimg/www.rcu...b0801fdb65.jpg
The Pull-Pull on outside in the tail.

https://cimg5.ibsrv.net/gimg/www.rcu...c8c390469f.jpg
The Pull-Pull exit in the tail.

https://cimg2.ibsrv.net/gimg/www.rcu...3772efe956.jpg
The rudder servo after relocation to the front in fuselage, just behind and between-below the wing adjusters.

https://cimg1.ibsrv.net/gimg/www.rcu...b1e18f7177.jpg
The aramid lines going to the tail.

computermonkey 10-12-2018 08:36 AM


Originally Posted by bem (Post 12419046)
Hi,
After some searching on the internet I have found out that the wire tensioner I have been trying to find out who makes it is used in some Hangar 9 ARF's. But I can not find it as spare part at Hangar 9.
I will dig some more with help of Google.
/Bo

https://cimg8.ibsrv.net/gimg/www.rcu...06de53f963.jpg https://cimg9.ibsrv.net/gimg/www.rcu...5f5db29bc7.jpg

Here is the link your looking for
https://hobbyking.com/en_us/pull-pull-3mm-clevise-quick-link-couplers-26mm-length.html
https://hobbyking.com/en_us/pull-pull-2mm-clevise-quick-link-couplers-20mm-length.html

computermonkey 10-12-2018 08:38 AM

Blue control horns
 
Bem,
What brand and where did you find the blue control horns?

bem 10-13-2018 07:59 AM

computermonkey,

The blue Control horns was shipped with my Oxai (now Hui Yang F3A) Galactika plane. They can be bought via a Hui Yang F3A reseller.
However these blue Control horns can be bought for example from this Japanese hobby shop, Morris-Hobby:
NTSƒxƒAƒŠƒ“ƒOƒz[ƒ“iVŒ^j

It is actually Narutech Service (NTS) that make them, at least they are marked NTS on the plastic bags as You can see if You click on the image in above link.
They are very nice and good qualtity horns, it is a small ball bearing on them.
Morris-Hobby has many nice accessories for RC and F3A. Just click around on their site and Yoy will see.

/Bo

https://cimg1.ibsrv.net/gimg/www.rcu...1a853ad575.jpg

speedracerntrixie 10-14-2018 08:04 AM


Originally Posted by computermonkey (Post 12470034)


These may work out for you.

https://www.soaringusa.com/Brass-Hor...ategory_id=136

tarts 02-22-2019 06:10 AM


Originally Posted by speedracerntrixie (Post 12425257)


Can't get much lighter then this. Control horn is CF tube with CF rod inside. Dubro aileron connector is glued onto CF rod with thin CA. Cable is nylon coated Kevlar, crimped with aluminum tube and thin CA for insurance. Shrink tube over crimp cleans it up a bit. Adjustment at servo only but Kevlar won't stretch so after initial tightening of the cables it never needs adjusting again.

Where does one get that nylon coated cevlar?

rcprecision 02-24-2019 03:41 PM

1) https://www.gravesrc.com/acp-composi...-038-50ft.html

2) https://store.acpsales.com/products/3479/kev-cord


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