78'' Extra

[Scooterpilot]

Pull-Pull Wire Explanation









I hope this drawing and the explanations below will help you determine the which system is right for you.


Example (A) is this most perfect geometry that there is. Why, because if you look at the relationship of the bellcrank to the rudder horn and both wires, you will find that they create a perfect rectangle. Where both the bellcrank (A2) and the rudder horn (A1) are the exact same length, and both pivot on there own center line or on hinge line. The wires also are the same length in relationship to one another. With this system, whether it is SWB's or another manufactures you need to slot where the wires exits in the fuselage, as the wires should NOT touch the fuselage at anytime.


Example (B) is a whole different animal. Why, because if you look at the relationship of the bellcrank (B2) and the rudder horn (B1), you find that they are NOT the same length. The rudder horn is on Hinge line but the bellcrank is not on it's own center line. The wires however are the same length in relationship to one another. With this system, the Bellcrank (B2) is shorter with an offset to the rear of the plane. This is done to keep the wire tension as much the same as possible throughout whole spectrum of travel. This system can be used with a slot or with an single exit hole in the fuselage. If you choose to use a single exit and are using SWB's products, please contact SWB for the proper location, as where the wire exits the fuselage while the rudder is in the neutral position is NOT correct!!!


Example (C) is also good geometry. Because again if you look at the relationship of the bellcrank (C2) to the rudder horn (C1) you find that they are the same length, but this time there is a equal offset (C3) in both the bellcrank (C2) and the rudder horn (C1) in relationship to where they pivot on there own center line. The wires also are the same length in relationship to one another. With this system, whether it is SWB's or another manufactures you need to slot where the wires exits in the fuse, as the wires should NOT touch the fuselage at anytime.

 

[RKEstes]

For anyone running the Valley View RC 40cc twin on this airframe and wondering about how to close the large spinner gap with the stock engine standoffs, I received some custom standoffs today from www.customstandoffs.com. They are 3/8" long. I will report the results when I get them installed later this evening.

 

[SnowDog]

Craig does great work; I'm sure those will work well for you.

 

[Scooterpilot]

I ordeded these for the VVRC 40cc:
http://www.swbmfg.com/products/Stand-offs.html

 

[RKEstes]

I ordeded these for the VVRC 40cc:
http://www.swbmfg.com/products/Stand-offs.html

Those are nice and I considered getting them but the shortest length offered was 1/2". On my plane that will still leave a little over a quarter inch spinner gap. I was trying to get it to around an eighth inch or so. Of course your results may vary!

 

[Enterprise]

These and a washer should work and be available locally at the LHS and hardware store.

http://www.horizonhobby.com/products/EVO3311

 

[Scooterpilot]

I'm trying to set up my throttle linkage. I have a VVRC 40cc and I'm using the existing throttle servo location under the motor box. This is my first installation of this type, so if any of you have any pic's I could look at that would help greatly with the installation or recommendations, I'd really appreciate it.

The configuration offsets the motor throttle arm well above the servo


Thanks
Chuck

 

[RKEstes]

Here is mine and it works fine so far after 8 flights. The angle is not great but on the throttle I am not too concerned about the geometry. I have a Savox SC-1268SG servo on it with tons of torque and it is not binding in any way. I used a Dubro 4-40 rod and ball links. The Dubro links came with a spacer That i inserted between the servo arm and the ball link to offset the ball link to clear the bottom edge of the motor box as you can see in the pic if you look closely. You will have to use a really short socket head screw to clear the muffler. I just cut my socket head screw off with a Dremel.

 

[Scooterpilot]

Thanks for the pic's, it gave me some ideas.

I used 2/56 ball links for the thottle. I recessed the non-structural overhang portion of the engine box so there is no binding from idle to full thottle. Also, I found a servo arm that is narrow compared to the plastic servo arms. Before I intalled the narrow servo arm I had a slight bind. As you can see from the pics, there is no binding at the servo when throttle is closed.

I still have good resolution for the throtle servo, it's at 100%/100%. :banana:

All I have left to do is: cut the canopy for the exhaust, install the fuel filler, tank and fuel lines; then, I'll balance the little beast.

Again, thanks for the help!

 

[gyro]

Went ahead and ordered a 78" for a winter build. Hopefully she'll get the new DA-35, we'll see.

I've got high expectations for this airplane from all of you who constantly praise it. I'm pretty rough on planes in flight, with lots of high energy spins and tumbles. Hopefully THIS Extra can hold up