05-09-2013, 11:06 AM
The elevator servo, A HXT 500 is mounted in a tray inside the fuse just behind the Trailing edge of the wing. 246
The servo is connected to the elevator control horn by a ridged push rod. In the past I’d made these from spruce but having run out this one is a ply balsa ply sandwich. It’s very ridged much more so than a length of 2-56 steel push rod wire and about ½ the weight as well. 247
The last pic shows the z-bend at the servo control horn end. The wire was tapered down on the bench grinder till the end fits the control horn nice and neat then the z-bend was put in. The other end was ground to a point and bent at 90 degrees to push into the timber before it’s bound with thread and bonded with CA. When grinding these thin rods I always grind them so the axis of the rod is tangential to the grinding wheel. What this does is make sure that all the scratch marks, from grinding, run length wise along the tapered wire. If the scratch marks go around the wire it makes it much weaker and it will often break when being bent. I really like to make my own push rods that way I can get the fit of the rod or clevice pin nice and neat in the controll horn. It's improtant to reduce slackness as much as possible in the control linkages of quick little machines like this. It helps in any model actually 248
For safety reasons, it’s a very good idea to remove any tool rest from the bench grinder before doing this!! Whenever grinding something thin like wire, always make sure that you hold it so it can pull out of your hands if it snags on the wheel and won’t drag your hand into the machine.
The servo is connected to the elevator control horn by a ridged push rod. In the past I’d made these from spruce but having run out this one is a ply balsa ply sandwich. It’s very ridged much more so than a length of 2-56 steel push rod wire and about ½ the weight as well. 247
The last pic shows the z-bend at the servo control horn end. The wire was tapered down on the bench grinder till the end fits the control horn nice and neat then the z-bend was put in. The other end was ground to a point and bent at 90 degrees to push into the timber before it’s bound with thread and bonded with CA. When grinding these thin rods I always grind them so the axis of the rod is tangential to the grinding wheel. What this does is make sure that all the scratch marks, from grinding, run length wise along the tapered wire. If the scratch marks go around the wire it makes it much weaker and it will often break when being bent. I really like to make my own push rods that way I can get the fit of the rod or clevice pin nice and neat in the controll horn. It's improtant to reduce slackness as much as possible in the control linkages of quick little machines like this. It helps in any model actually 248
For safety reasons, it’s a very good idea to remove any tool rest from the bench grinder before doing this!! Whenever grinding something thin like wire, always make sure that you hold it so it can pull out of your hands if it snags on the wheel and won’t drag your hand into the machine.
“The knack of flying is learning how to throw your machine at the ground and miss.”
"When once you have tasted flight, you will forever walk the earth with your thoughts turned skyward, for there you have been, and there you will always long to return." ~Leonardo Da Vinci