DrFun

My Feedback: (4)

Hello All,

I am trying to install the Dubro Heavy Duty Pull-Pull System .41-.91 Dunro # 881 for the rudder of my GP Extra 60.

The problem is it is practically impossible to install this system with the supplied white plastic torque rod coupler.

The supplied white torque rod coupler is simply short

First picture shows the instructions,

Second picture shows the actual with supplied white plastic horn

Third picture shows that the holes in the horns are inline with the hinge line looks a little off in picture but it is inline,

The fourth picture is what Dubro should supply with this set. The black torque rod coupler is from Dubro Heavy duty horn set.

I expected this to be a problem before drilling the holes and looked arround for those balck horns but no one sells them, and decided to try make it work.

But no way it will work the supplied base plate diameter is the same as the white horn to screw distance You can't have the bevel and have this working without cutting the aliminum base plate.

Now I paid $10 for this set and it does not work, I can't buy the black long aileron torque rod couplers alone and I have to buy the Dubro # 867 fpr $6 to get the black couplers and redrill hole at a backward place insert dowel and drill again.

This is simply a design flaw. What do you think, am I missing something?

If I want to have the horn holes in line with the hinge line you have to drill it close to the LE but then the base plate is the problem.

birdnest

Hmmph, you're right, the plastic arm is too short. What were they thinking? Since you have a flat control surface, maybe you could just do without the base plates. I can't tell from your pictures (nice, by the way) but if you have a dowel/hardpoint there, you probably can do without it.

I have the same hardware included for the extreme flight yak I am building. The rudder is airfoiled and the baseplate will be tilted a little so there will be less material overhanging the hinge line. Still, I will have to move the horn back a little so that the plate fits. The hole in the plastic arm will be behind the hinge line, which I believe is OK as long as it's just a few mm's.

Peter

DrFun

My Feedback: (4)

I have the dowel, I tried removing the base plate but then the problem is as the control horn is so close to the LE of the rudder it limits the throw that I want from the rudder, I could gain more throw from the plastic horns. So the best thing for me is still to move the horn back.

kris_762

Based on my research you actually want the holes in the horns to be slightly behind the hinge line. See http://members.cox.net/bdfelice/Ackerman/ackerman.htm for more info. If you move the horn back 1/16 or 3/32nd of an inch that should help keep the base from interfering with the vertical stabilizer. If after moving the horn back the base still interferes then you could file a little bit of it away.

Kris

Gringo Flyer

My Feedback: (18)

Dubro stuff is great (if you already know exactly how to use it). A lot of their stuff doesnt have instructions on how to install and when they do have instructions they are very vague. It would be great if they could include a little more detailed install info. I made a mistake yesterday installing the standard pull pull system on a rudder. After the fact I realized what I had done. If the directions had been a bit clearer I wouldnt have had that problem.

Red B.

One simple solution is to simply ignore the problem and let the holes in the horns some distance behind the hinge line. Measure the distance and then make the holes in the servo disc the same distance behind the servo disc mounting screw. This will take care of your problem but it presumes that you have access to some kind of servo disc instead of straight servo arms.

/Red B

birdnest

The only other thing I could suggest would be to not use the aluminum cones as well as the plates, just use the threaded rod. Kind of a waste though... You can take a pair of 6-32 blind nuts, grind off the barbs, then thread them down the rod and epoxy them to the rudder surface to brace/stregnthen it. Perhaps this would give you the clearance you need for decent rudder travel and you wouldnt have to re-do things. Where do you fly, you are around the corner from reading.

peter

JoeAirPort

My Feedback: (41)

You could just grind the base plates to clear the hinge.

You could move the hole back a little.

Use the Sullivan horns: http://www.rcuniverse.com/forum/upfi...76/Rp43286.jpg

DrFun

My Feedback: (4)

Altough Sullivan horns perform good installing them is not that easy in my opinion.

They would work for this application where the surface is flat but for ailerons they are very difficult to lineup with the back plate and I spend considerable amount of time with lining the screws with back plate. The same for plastic horns. So thats why I choose this. And the Heavy duty single horns I used for elevators and ailerons both were installed in matter of seconds drilling a single hole and thats it.

kris, I had also seen that web site but decided to go with the horn holes in line with the hinge line, as I read in couple of places it is the right way. I am no expert of pull-pull and hence this is my first pull pull installation, but having the same distance in both horns as well as servo arm was my goal to prevent any slop in the pull pull lines.

Red B., I have the wheel will experiment with it.

birdnest, I fly at
www.lvrcs.com

Thanks for your replies, I sent an email to Dubro asking where I can get those black couplers, Let's see.

DrFun

My Feedback: (4)

Well Dubro replied to my email and they offered to ship black couplers, now I am happy and A+ customer service, they stand behind the product they sell.

My problem is a small item and maybe detail for a company, if they change the shipped white ones with the balck ones in future productions then this is good for them and us.

In each plane I use $100+ worth of Dubro products and they are not big planes, and with this will experince I know that they stand behind the product they sell.