Twisted Hobby’s Crack Yak 55

Bricks

Master member
To make the hinge lines easier for the servos to move what needs to be done before the build is, take all the control surfaces fold them back over themselves, put weight on them so they stay flat and let it sit over night. For EPP this is one of the better ways to loosen them up.

Those links do not take much for heat to melt them, depending I will use my solder gun to shrink the tubing then still CA them.
 

Ketchup

4s mini mustang
To make the hinge lines easier for the servos to move what needs to be done before the build is, take all the control surfaces fold them back over themselves, put weight on them so they stay flat and let it sit over night. For EPP this is one of the better ways to loosen them up.

Those links do not take much for heat to melt them, depending I will use my solder gun to shrink the tubing then still CA them.
I already used the method of folding back the control surfaces, and the rudder moves very freely, but I think that the stress is caused by a bend in the control rod. There are plastic holders that hold it in place and they start to go upwards towards the rudder, but that causes a bend. I think that it should be just fine though, since the resistance isn’t enough to damage a servo.
 

Bricks

Master member
When you glued in the pieces that holds the control rods are they running straight to the control surface? Once CA`d in they should not lift or move.
 

Ketchup

4s mini mustang
When you glued in the pieces that holds the control rods are they running straight to the control surface? Once CA`d in they should not lift or move.
They do not move at all, but they also do not go straight to the control surface. I think that it was an odd choice in the kit, but maybe there was a reason for them to bend the control rod?
 

Bricks

Master member
it could be the markings are off if you build a new one ever, keep the control rods straight no matter where the markings are. Set the control surface to neautral then line up the control rod supports. The way I do it is mount the control rod to both the surface and the servo. With the supports on the rod and then set the supports to where the control rods run straight and CA in place.
 

Ketchup

4s mini mustang
Ok, so I haven’t touched this for a while, but I decided to get back to it now. A couple months ago the rudder control horn broke, so I was going to cut out another one with a gift card, but I wanted to ask if anybody has a better idea before I do it. Also, I wanted to post a picture of the rudder pushrod supports to make sure that they are straight enough. If not then I can cut them out and reglue them straight using the method that @Bricks mentioned.


image.jpg
 

Ketchup

4s mini mustang
Also, for the aileron servo horn, how do I cut off the pieces of the screw that stick out? I was going to use a Dremel like the instructions say, but I wanted to know if there are other methods.
image.jpg
 

Bricks

Master member
Also, for the aileron servo horn, how do I cut off the pieces of the screw that stick out? I was going to use a Dremel like the instructions say, but I wanted to know if there are other methods.
View attachment 166423


You want the screws going up and away from the servo so there is no need to cut them, and when installed the Y shape goes towards the nose of the plane.
 

Ketchup

4s mini mustang
I cut and installed the aileron servo horn, but when I went to do the aileron linkages I couldn’t find the control horns. I might have lost them :rolleyes:. So I was thinking about replacements. Can I just use a standard FT control horn, or do I need to cut one out of a gift card? I will spend some more time looking for the control horns, but I might not find them and ordering replacements would use cost too much. Also, are there any patterns for the twisted hobbys control horns? I would cut my own but I don’t know what shape or size to make them.
 

Ketchup

4s mini mustang
From the control surface to the control rod hole is roughly a 1/2 inch centered on the hinge line.
Thanks! I will make a new control horn (if I can’t find the original in the next few days). I already have to make one for the rudder anyways.
 

Ketchup

4s mini mustang
All right! It took me a while since this plane was mostly a side project, but it’s done! I went to the field today and realized... I need more planes. I am waiting for receivers for 2 planes, but this one already had a receiver, so I chose this to work on today. I made aileron control horns and glued them in, then I did all of the linkages. After that I plugged everything into the receiver, bound the receiver and calibrated the esc, and I was done! I want to maiden tomorrow morning. Ok, so I have a few questions that I want to get out of the way before maiden. 1. Do you guys have any recommendations for rates and expo? 2. How do I make sure that the battery location is good? Do I tape it on, fly it, make adjustments, and then cut the hole when I’m completely finished? Finally, the area around the vstab is flexing a bit when I use rudder. I made sure that it all moves freely, and it isn’t damaging anything, but I wanted to know if I should glue something in place to stop it. So yeah, thanks for all the help @SquirrelTail and @Bricks . I hope that the maiden goes well!
 
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OliverW

Legendary member
All right! It took me a while since this plane was mostly a side project, but it’s done! I went to the field today and realized... I need more planes. I am waiting for receivers for 2 planes, but this one already had a receiver, so I chose this to work on today. I made aileron control horns and glued them in, then I did all of the linkages. After that I plugged everything into the receiver, bound the receiver and calibrated the esc, and I was done! I want to maiden tomorrow morning. Ok, so I have a few questions that I want to get out of the way before maiden. 1. Do you guys have any recommendations for rates and expo? 2. How do I make sure that the battery location is good? Do I tape it on, fly it, make adjustments, and then cut the hole when I’m completely finished? Finally, the area around the vstab is flexing a bit when I use rudder. I made sure that it all moves freely, and it isn’t damaging anything, but I wanted to know if I should glue something in place to stop it. So yeah, thanks for all the @SquirrelTail and @Bricks . I hope that the maiden goes well!
I would start with 100% rates and 25% expo. I typically run mine with no expo, but it's all personal preference. And do exactly what you were talking about with the battery!
 

Bricks

Master member
Me I put Velcro along the side of the fuselage that way I can adjust CG, if it is windy I can move CG forward or where ever I want it.

I set up 3 rates for mine roughly 35% 70& and 100% expo varies from 30% to 60% each control surface will have it`s own rate and expo. Once in the air you will find your sweet spots.
 

Ketchup

4s mini mustang
So today it flew! I just did a flight to verify the cg and then came home. I might not fly again today because I realized that this thing really cannot handle wind... at all... I want to get a couple flights in every day this week to practice and learn the plane, but I will have to wake up early to avoid the wind.