famousdave

My Feedback: (61)

A 20 pound CA Models 31% Extra I am finishing up on ended up a tad tail heavy. I have decided that my 5735 giant rudder servo is too heavy and too far aft. Rather than add noseweight to balance (everything else is already as far forward as possible) or move the 5735 forward from its aft position... I thought it would be better to simply replace the 5735 with a single 8611 and move the 8611 one servo bay forward. I am sure the balance would be right on then.

I have already perfectly rigged the pull-pull setup, so it sucks that I have to cut and re-rig the cables, but so be it. The problem I am having is finding a suitable arm for the 8611 that will allow me to use the existing Nelson 4"arm.

My current setup looks like the picture below.. a stock 5735 double sided metal servo arm bolted to a Nelson 4" Rudder Arm. Perfect fit out of the box... It would figure that JR wouldn't include a decent double arm for my $100, but that is the JR way.

I want to preserve the setup (including horn spacing at the rudder end) so using the 4" arm is my preference rather than stepping down to an MLB 3" arm and adjusting the rudder horns. The 8611 does not come with a metal double arm. I do have plenty of the HD plastic servo arms that will fit JR, but I have heard that using reinforced nylon arms have created failures on the 8611s so I don't really want to use nylon.

MLB makes excellent arms - I have many of them, but the inverted design makes it impossible to bolt up to the nelson arm (when placing the nelson arm on the bottom of the MLB arm the screw heads hit the top of the servo case) and they have had fitment problems due to the JR spline varying in tolerance. Nelson might make something, but they never answer the phone, and their website says they can't ship anything for weeks do to Uncle Sam...

Any suggestions? The Nelson web site says use Nylon, I don't buy it. 260 OZ on nylon even on a 31% seems destined to disaster. I can take a uni-hub and drill it out to match the nelson arm, but there has to be a more elegant solution....

Anyone??

DP

DKjens

My Feedback: (50)

DP,
I believe Nelson also sells a round metal disk for the 8611, which you can bolt the 4" double arm to. The disk is even with a split spline to tighten around the servo spline. If I'm wrong, I'm sure SWB make a double arm you can use. I use the SWB arms myself, they also tighten around the spline.
DKjens

JohnVH

My Feedback: (38)

Order up a aluminum arm and bolt it to it.

otisflies

Here's the setup in my 31% CA. Got the small arm and the big glass one both from airwild. The big epoxy bellcrank is 5 inches long. The 8611 on this setup is more than strong enough for this plane.

Terry

John Murdoch

My Feedback: (11)

Try Scott at SWB. http://www.swbmfg.com/ I think he has a 4 1/4 outside to outside, double lock arm...

GoeKeli

My Feedback: (18)

I bought the uni-hub from airwild to do exactly that but just went with their servo arms instead. I also heard that nelson has one too.

Joe

famousdave

My Feedback: (61)

Thanks for all the tips guys... Nelson is closed for the next two weeks according to their website and no one was answering the phones ... the others I called did not have the adjustable locking hub for JR in stock (and of course I have 10 of them for Hitecs) so I decided to move a few things around and leave the servo where it is. I moved the ignition module into the cowl area, moved the batteries a bit more forward as well as the regulators and receiver. I also changed the rudder horn from a 10-32 bolt to a nelson laminated horn (weighs 1 oz less)... got it balanced right on the tube...

All ready to fly just in time for the 1st windy and rainy days we've had here in 9 months!!

DP

vypr

My Feedback: (6)

Mind posting some more pics? I love the looks of your scheme and I'm looking for ideas right now so...