Extra 300 flies with Durant Direct Drive

Looking for the ultimate in slop free control surfaces, Dean Nistetter decide to try the Durant Direct Drive control system on his new Carden Aircraft Extra 300.  Dean was kind enough to document his installation as he proceeded, and we are pleased to be able to pass along that information below.


As you know I am near completion of building one of your Carden 40% Extra 300's and that I have installed John Durant's Direct Drive servo system. You indicated you would like some pictures in this regards. Although it is after the fact I had taken some pictures you may be interested in seeing. A few of the pictures are a bit out of focus but most are very clear. I have reduced their size and resolution for purposes of this e-mail.

You will see in the pictures some single servo boxes and a dual servo box for the rudder. The pictures should be self explanatory even though a few of the actual installation steps are not shown. There are a couple of other resources explaining the Durant Direct Drive system. First is John Durant's website: Durant Direct Drive. Within his website are various instructions for installing single, dual, and triple servo control boxes. The following link shows his instructions (with drawings) for installing a dual servo box which I used on my rudder: Dual Servo Box Mounting Instructions.  His instructions are very clear and descriptive. You may want to take a look at them as they are very well done. A second resource would be the article submitted by Rick Byrd for the AMA Magazine showing how he installed the Durant Direct Drive system on two of his Carden Yaks. I believe the article was in the December, 2007 issue?

Although this is my first time to install this system in a plane I must say it was very easy and straight forward. Once you do one you quickly discover it is not at all as intimidating as you thought before hand. It is just very different from what most of us grew up doing. Also, I am very pleased with a couple of benefits that this system yields over the traditional control horn method. It saves overall weight by not having hard points, push rods, control horns, servo mount screws, or ball links. Across 8 servos this adds up quickly! The system yields no slop in linkages for a very precise feel. Since the control surfaces are actuated directly off the servo it has a very linear feel. Finally, both sides of the wing/stab/rudder are completely flush with no protruding objects. These are the benefits I can see from the system from just the building phase. I'm sure when I fly it I'll recognize other positive features.

John and Rick. I copied both of you on this e-mail because you are the owners and pioneers of this system and because you have been helpful to me in the learning process. Dennis may be interested in more input from either of you at some point in the future.

Dennis, one final note. I traditionally resist change so I am sometimes slow to adapt to it. John and Kevin Braziel live near me and have been after me to try the Direct Drive system for quite a while now (they both use it). I finally did it and to this point am glad I did. John recently built on of your Carden Yaks and his plane is one of the best I've seen fly. John and Rick both fly Unlimited and are two of the best flyers in the SC Region if not the country. They certainly have skills but they also have great equipment (Cardens) with Direct Drive servos. I feel like this combo will eventually catch hold with others if they just see and hear more about it.

Anyway, I hope the attached pictures are helpful.


Servo box for single servo installation.

Rudder recessed for servo box clearance.

Bottom view of aileron servo installation.

Direct drive offers plenty of travel.

Ply plate gets trimmed to fit on your control surface.

Trimmed and lightened - ready for installation.

Elevator recessed for servo box clearance.

View of hinge line after final fit.

Completed stab and elevator assembly with single servo box.

Assembled wign and aileron with two single servo boxes.

Rudder post with double servo box.

Rudder post side view.

Rudder fit to the fin / rudder post with a double servo box assembly.

Finshed stab and elevator.

Stab and elevator complete - bottom.

Completed wing and aileron with two individual servo boxes.

Single servo box installed at the hinge-line.

Rudder post relieved for installation of a double servo box.





















View Dean Nistetter's Split Baffle / Cowl Installation