Replies to This Discussion

Permalink Reply by Steven Winn on May 21, 2015 at 5:48pm

Agreed. I also watch closely for FOD. I covered the center, but the stick bottoms are close to the floor. A cig lighter would likely jam them up nicely....

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Permalink Reply by Kurt Satter on May 21, 2015 at 8:55pm

I don't smoke ... Thanks guys.  I'll be looking closely at the 750 dual stick kit option.  Did I mention that I'm planning on the no-fuselage-slot flaperon actuators.  I have the parts made and a couple of nice 5/8" Teflon bearings.  Lots of these flying and pretty straight-forward.  My only other "mods" (besides the folding wing option) are vortex generators and wing/fuselage stiffeners.

Thanks again...

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Permalink Reply by John Austin on May 22, 2015 at 5:56am

Here's the covers my upholstery guy made for my dual sticks. They are secured by the front seat base screws and hang down like a skirt. He used foam-backed vinyl to give it some stiffness and shape. They have Velcro closures down the front so they can be easily opened and flipped aft for inspection of the stick mechanism. An elastic ponytail loop gathers the top of the stick boot against the stick (not installed in these pictures):

John

N750A

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Permalink Reply by Kurt Satter on May 22, 2015 at 6:18am

Too pretty to be a homebuilt!  Looks really nice.  I also like the console between the seats  Nice place to mount what looks like a fuel-selector switch.  Also, placing the throttle there makes it accessible to the "co-pilot".  Dose this mean you did not install dual throttles?

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Permalink Reply by John Austin on May 22, 2015 at 6:35am

Dual sticks make dual throttles totally unnecessary! Just put the throttle in the center console or center of the panel and pilot/co-pilot have equal access. It's waaay easier to fly from the right seat and use your left hand on the center throttle than fly a Y stick from the left seat and try to use your left hand to manipulate the stick so you can use your right hand to adjust radios, gps, etc!

I'm right-hand dominant but fly my dual stick 90+ percent with my left hand because nowadays with all the knobs, buttons, and touch-screen devices, I'd much rather use my "good"/dominant right hand to manipulate all those devices! It is equally comfortable, however, to occasionally give the left hand a rest and fly with the right hand - either arm falls comfortably into your lap ... Zenith got the stick height "just right!"

John

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Permalink Reply by Kurt Satter on May 22, 2015 at 9:11am

If you replaced the manual flap control with a servo, did you use the same Ray Allen servo as for the elevator trim?  Looking at the plans, it appears that the 7C3-2 control lever only moves ~11mm.  The T2-7A servo has a 17 mm range with an operating thrust of 20 lbs (max 40 lbs).  It also looks like a fairly straight-forward job to replace 7C3-2 with the servo and push-rod.  Any thoughts out there?

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Permalink Reply by Joe Spencer on May 22, 2015 at 12:25pm

Steven I looked at your dual stick mod closely, it's nice and elegant.

I did wonder if those standoff brackets (that hold the torque tube and its bearings) are heavy enough to stand the lateral thrust loads from aileron actuation. Also wonder if the seat structure it's fastened to is heavy enough to stand the loads over time w/o cracking at the rivets from the rocking load of every aileron application...I don't remember what thickness that panel is. The arm of the torque tube center in its brackets is way longer that the short leg of the angle so it(the short leg of the angle bracket) gets magnified loads. I don't know how much load there is on those brackets, it may be small due all the geometry involved between the aileron and the control stick...but it also may be large as in all the aileron loads end up there. I don't know and so I assumed heavy loads and put a thrust brace there. The plans TT bearing and it's mount in the front seat panel will take major side loads if there were any but there's no lateral TT to try to shift so all we get is bearing wear to the sides from aileron loads and at 360 hours mine is definitely sloppy laterally.  Maybe you've already investigated those loads and know better. If so please excuse and disregard all the above. My brace may be totally unnecessary....but if it has to do with the controls I rather err toward overstout. I'll try to post up a pic. Oh and mine is a 701, not sure if yours a 750 or 701...if it matters

Joe

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Permalink Reply by Kurt Satter on May 22, 2015 at 1:29pm

I have the drawing for the 750 dual sticks option kit from Zenith, but I don't have the 750 plans so I don't know the thicknesses of the parts you speak of as compared to the 701.  I'd be interested.

7F11-1 is 0.032" .. what thickness is 75F11-1

The upright L-Angles for attaching the stick assemblies to 75F11-1 are a stout 0.75x0.75 and 0.093".

The hinge plates and gussets are 0.040" and the flaperon control horn is 4130

Permalink Reply by Steven Winn on May 22, 2015 at 3:30pm

Joe,

I also have a 701. The standoff brackets that hold the pitch yoke tq. tube are .090 6061-T6. The extrusions they attach to are .090 7075-T6. Very stiff.

I placed another full height (floor to top of seat) extrusion behind the fwd seat bulkhead creating a sandwich. I  also was concerned about the bulkhead cracking at the rivets exactly as you describe.

I had every intention of installing fillet supports on the inner sides of the tq. tube standoff brackets, but once I got it all riveted together, it was very strong/stiff so I skipped them.

You can see the rear extrusion doubler in this photo.

Permalink Reply by Joe Spencer on May 24, 2015 at 5:09pm

Here's mine. it's not as simple or light as Steven's...the reason is mostly because I still have the plans flap lever which I've always liked. I know many don't. The electric is fine my only thing with that is the one I had on my RV8 was slow, real slow. I think they're same brand unit don't know for sure. Anyway, with the plans flap lever we can't take advantage of the lightening hole in the seat bulkhead for lower stick clearance so have to make the lower stick short. That means we gotta put the pitch TT mounts O/S of the sticks so we can get the aileron actuator rods over to the original TT. Also have to offset the left stick back to the center as it's to the right a bit. Also had to notch the pitch TT for clearance on the aileron actuator stuff. I spent musta been a week fooling around with that rig. It was well worth it tho.

With the very short lower stick and matching tabs on front of the original TT very small dimensional differences in the arms makes a huge difference in the leverage so it's easy to get it off a little. I had to make one cut and reweld adjustment on mine. Initially, I went for 1:1 on mine as that's what it looked like the original had with the stick fixed directly to the TT. Or maybe that's 0:0 if there is such a thing, beats me. Dunno what I ended up with but works good. That angle brace is probably gonna come out

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