The rod goes all the way through the aluminum profile - the profile is to a large extent just for looks.
1/4 Scale Cubs - Sig and Balsa USA, Rescue and Re-Build
- Thread starter Joker 53150
- Start date
The rod goes all the way through the aluminum profile - the profile is to a large extent just for looks.
TooJung2Die
Master member
Definitely has a much more scale look than the original struts.
Switching away from the struts for a bit, as I'm taking the Cub to a friend's place to do some engine tuning. I can make the engine run, but really tuning it so it runs WELL is another story. This engine has never quit on me in flight (other than when I ran it out of gas...), but it has been running a bit rich and spitting some excess oily residue. Transition from low to high speed isn't as smooth as I'd like, but I'm afraid to mess with it too much and accidentally make it worse!
So to get the tank back in I'm replacing the bung, all fuel line, and especially the clunk line. In the pic below you can see the original clunk line that was installed less than 2 years ago. It's hardened up and also got a funky curve so if I did any "evasive maneuvers" there is a good chance it would start sucking in air instead of gas. The new black line is about 3x the price but it's supposed to stay soft and flexible for years, which is why many people run it for clunks only. The wire wraps around the ends of the line are stainless to avoid corrosion over time.
So to get the tank back in I'm replacing the bung, all fuel line, and especially the clunk line. In the pic below you can see the original clunk line that was installed less than 2 years ago. It's hardened up and also got a funky curve so if I did any "evasive maneuvers" there is a good chance it would start sucking in air instead of gas. The new black line is about 3x the price but it's supposed to stay soft and flexible for years, which is why many people run it for clunks only. The wire wraps around the ends of the line are stainless to avoid corrosion over time.
Wow, the difference from a little tuning by somebody who knows how to do it is amazing! The Cub only needed a little leaning on the low end and now it runs much smoother and with a better transition to high speed. I need to dial in a good throttle curve on the Taranis to really call it done, however. But that’ll be done another day.
It's taken far longer than I expected, but the second set of struts is almost done. All it really needs is some LocTite and paint. If I knew how long it was going to take I probably wouldn't have gone forward with the upgrade, but seeing it now makes me glad I didn't know! 
After finishing the small details I'll turn my attention to fixing the side window and upgrading the door with some type of latching mechanism to keep the door closed in flight. The last part of the project will be making a new cowl with the new dummy engine I started a while back. The cowl was ordered from Fiberglass Specialties this weekend, but they're closed for a few days for some reason. Oh well, that gives me time to wrap up the rest of this project.
After finishing the small details I'll turn my attention to fixing the side window and upgrading the door with some type of latching mechanism to keep the door closed in flight. The last part of the project will be making a new cowl with the new dummy engine I started a while back. The cowl was ordered from Fiberglass Specialties this weekend, but they're closed for a few days for some reason. Oh well, that gives me time to wrap up the rest of this project.
The new cowl from Fiberglass Specialties showed up a few days ago, so now it's time to start the work on making it fit. The carb and muffler both will stick out from the sides - not ideal, but that's the joy of running a gasser. Here is the original cowl with the cut-out for the carb. Notice that this carb has the molded Continental engine cylinders. While flying they look fine, but on the ground they lack detail. That'll change soon...
The new cowl is being trimmed as little as possible to fit over the carb, muffler, spark plug, cylinder head, and plug cable. The original cowl has the entire bottom cut out for some reason which allowed me to flex the cowl to fit over the muffler and carb. Currently the new cowl is only being trimmed as needed so it can fit, meaning I have to remove the carb, muffler, and spark plug to get the cowl on or off. Not a fun project... I'm considering making the cowl a 2-piece unit with a cut-line to separate the top & bottom halves. In theory this would keep me from having to take the engine apart every time I need to get at the engine.
The new cowl is being trimmed as little as possible to fit over the carb, muffler, spark plug, cylinder head, and plug cable. The original cowl has the entire bottom cut out for some reason which allowed me to flex the cowl to fit over the muffler and carb. Currently the new cowl is only being trimmed as needed so it can fit, meaning I have to remove the carb, muffler, and spark plug to get the cowl on or off. Not a fun project... I'm considering making the cowl a 2-piece unit with a cut-line to separate the top & bottom halves. In theory this would keep me from having to take the engine apart every time I need to get at the engine.
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A few months ago I started building the dummy engine for the Cub, and today I started test-fitting the parts. They're all just taped in place for now and I like how it's starting to come together. Once all 4 cylinders are ready I'll mark the cowl so they can be recessed slightly and so the cowl can be (probably) cut to make it a 2-piece. The "engine" will hopefully draw some attention away from the massive muffler. The original muffler was modified (hacked and booger-welded) to fit inside the original cowl. The welds weren't done very well and it leaked exhaust residue all inside the cowl. Plus it really cut down on the size of the muffler chamber which may rob me of power.
A little final sanding is still needed to help hide the seam on the cylinder head. Plugs, wires, exhaust, and intake still need to be fabricated. This cowl isn't quite as long as the original one, so the prop sticks out the front about 1/4" farther at the nose.
A little final sanding is still needed to help hide the seam on the cylinder head. Plugs, wires, exhaust, and intake still need to be fabricated. This cowl isn't quite as long as the original one, so the prop sticks out the front about 1/4" farther at the nose.
nhk750
Aviation Enthusiast
What servos are you using for the control surfaces. I was thinking about the D645MW Hitecs for mine.
I’m using all the original servos that came with the plane, no idea what they are, however.
All servos in the fuselage are hidden under the floor, nice and neat.
Tackling the door has been on my radar for over a year now. When I got the plane there was only a single magnet and friction holding the door and window closed. While that worked fine on the ground, the door would always pop open during flight. The first flight could have been it's last, as when the door flops down (open) it hits the power switch which kills power to the receiver. If it hit hard enough, down she comes!
So I upgraded a few things. First, I modified the power switch so that you push it IN to turn it on, and pull it OUT to turn it off. Now if the door hit the switch nothing bad would happen. In theory? I also added an extra magnet to the door in hopes it would stay closed in flight. No dice, most flights it would still open, but at least I wasn't worried about the power being cut. To keep the door and window closed I resorted to putting a piece of Blenderm tape across both pieces and securing it to the windshield. It wasn't pretty, but did the trick and came off nicely at the end of a day at the field.
Time to FINALLY make a better door latch! I've seen this done a few times on bigger scale Cubs and decided to try it myself. Basically it's a dual latch system with a spring to keep the latch closed at both the front and rear of the door. It's probably easier to just post the pictures than describe how it's made, so here they are.
A spring will be added inside to help keep the latch in the closed position (see pic above). The inner piece is made from heavy brass sheet held in place on a handle made from threaded pushrod material.
The side window will be kept closed by using a couple short metal rods that will key into the top of the door, so the window only opens when the door is opened. In theory...
So I upgraded a few things. First, I modified the power switch so that you push it IN to turn it on, and pull it OUT to turn it off. Now if the door hit the switch nothing bad would happen. In theory? I also added an extra magnet to the door in hopes it would stay closed in flight. No dice, most flights it would still open, but at least I wasn't worried about the power being cut. To keep the door and window closed I resorted to putting a piece of Blenderm tape across both pieces and securing it to the windshield. It wasn't pretty, but did the trick and came off nicely at the end of a day at the field.
Time to FINALLY make a better door latch! I've seen this done a few times on bigger scale Cubs and decided to try it myself. Basically it's a dual latch system with a spring to keep the latch closed at both the front and rear of the door. It's probably easier to just post the pictures than describe how it's made, so here they are.
A spring will be added inside to help keep the latch in the closed position (see pic above). The inner piece is made from heavy brass sheet held in place on a handle made from threaded pushrod material.
The side window will be kept closed by using a couple short metal rods that will key into the top of the door, so the window only opens when the door is opened. In theory...
I’ll show in better detail once it’s done.Maybe I just need more coffee this morning, but still I'm having a hard time visualizing how this all fits together...
The door itself is easy, adding a latch without completely rebuilding the door is harder. The 1/3 scale Cessna I rebuilt got all new doors and latches as well, but since the doors were scratch built it was easier to do.
In most cases magnets would work fine, but a pair of magnets on this one just wasn't enough (each magnet stuck to a small piece of metal on the door when closed). The combination of vibration, air pressure, etc was just too much.
Here is a better shot of what I'm doing. The first picture is how the mechanism will be when the door is closed and latched. The pushrods are pushed out and in to blocks mounted inside the fuselage. This effective "pins" the door front and rear. Epoxy is curing and the entire thing will get a coat of paint to make it all look a bit more authentic.
When I want to open the door I simply rotate the door handle 90 degrees counter-clockwise which retracts the pins far enough to clear the blocks mounted inside the fuselage and also clear the doorjamb, and the door opens right up. Right now it is fairly stiff moving and doesn't need a spring to keep the door in the latched position, but the spring will be added knowing this will all loosen up with time.
When I want to open the door I simply rotate the door handle 90 degrees counter-clockwise which retracts the pins far enough to clear the blocks mounted inside the fuselage and also clear the doorjamb, and the door opens right up. Right now it is fairly stiff moving and doesn't need a spring to keep the door in the latched position, but the spring will be added knowing this will all loosen up with time.
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