Sig 4 Star 20 EP Build Log

[TexMechsRobot]

So it begins. My goal is to have this completed and flying by August 5th. My club has an open house that day and I'd like to maiden it there. First sticks glued up on July 18th!

First impressions are really nice. The laser cut parts practically fall out of the sheets and everything is fitting like a dream. The plan calls for a hatch under the nose and I'll be converting this to a top hatch for easier access.

Purchased:

SIG 4-Star 20 .15-.25 GP/EP Kit 48"

APC 10x5 Thin Electric Propeller

Dubro Low-Bounce Smooth Wheels 2-1/2" (2)

Dubro Tail Wheel 3/4"

Dubro 2" Spinner Black

Great Planes Rimfire .10 35-30-1250 Outrunner Brushless

Great Planes Silver Series 35A Brushless ESC 5V/2A BEC

Tactic TSX20 Mini High-Speed 2BB Servo (4)

And let the building begin!

 

[nhk750]

Wow, I can hardly wait to build a laser cut kit, the cuts look so clean and precise compared to die crunch. Looks like a nice plane for aerobatics.

 

[TexMechsRobot]

It's far too under powered for advanced aerobatics. It will do some light stuff though due to the mostly symmetrical wing and full ailerons. I don't tend to do much with aerobatics though. I like to keep it simple

 

[Try-n-glide]

Seems like these things always take longer than you think they should. I started my "simple" build on 7/5, had it framed up in a few days......and I might finish it tonight if I hustle and don't run into any snags. Sure looks like a nice kit. Look forward to seeing the pictures as it comes along.

 

[nhk750]

It's far too under powered for advanced aerobatics. It will do some light stuff though due to the mostly symmetrical wing and full ailerons. I don't tend to do much with aerobatics though. I like to keep it simple

Practicing aerobatics will help flying skills immensely and will also help make muscle memory for emergency maneuvers when you loose an aileron or other problem. I am currently hitting a wall with my aerobatics and need to get back on the simulator to practice some moves. I eventually would like to get a pattern routine together for some fun flying and also work on the 3d flying some more. You wouldn't want to push your self with your nice planes though, probably should make a Tiny Trainer that you can beat up a bit.

This plane you are building though, even under-powered, should make aileron rolls, loops, inverted, hammerheads, ect pretty easy. It reminds me of the Sportster a bit and I am starting to like mine a bit more now.

 

[TexMechsRobot]

I'm pretty sure any muscle memory I had would be useless if I lost a control surface since all of the muscle memory would be based on standard control surface movement lol. And if you're hitting walls, maybe pick somewhere else to fly....

Got some more glued up last night. I have a few more pieces to install on the main wing and then a bunch of sanding to do this evening. Then I'll start the fuselage.

 

[nhk750]

I lost a control rod for one aileron on my Tiny trainer the other day and because I have been working on my knife edge flying I was able to land it with no damage. Apparently I didn't locktite the rod screw.

That wing looks very strong, that leading edge has its own full lenght spars! Cant wait to see it at the open house. I'm bringing my dad, he used to crash control line planes back in the 40's and 50's.

 

[TexMechsRobot]

More progress made. I still have some red to put on the wing and then black accents on the fuselage and possibly the wing as well. Then it's installing electronics and balancing for flight.



I love it when things line up like they're supposed to!

 

[Joker 53150]

Lookin' good! I had a 4 Star not too long ago, but passed it along to somebody who wanted it more than me. Looks like a super design with well-cut parts, maybe it should have stayed in my bull pen.

 

[RCMAN]

I built a gas version of this once, Great plane! Nhk is right, practice them aerobatics.

 

[NiCK_NaMe]

That model is looking good, I might make that one my next build.

 

[TexMechsRobot]

I'm enjoying it. It's going rather fast so that's nice. I've noticed that the laser cut parts don't fit perfectly with the plan drawings. It's almost as if they cut directly on the plan lines and so the little bit of material loss from the cut causes the parts overall to shrink. I noticed it most in the empennage. It is easy enough to account for but I was a little surprised.

 

[nhk750]

I bet they match up better than my T-Craft kit, jeez, I could have scratch built it better probably...

 

[TexMechsRobot]

Trying to wrap up the final pieces of this build and I keep running into tiny problems to solve. Apparently I need a motor mount in order to make the provided cowling fit. I'd still like to have this done by next Saturday so I need to find one quickly!

 

[RCMAN]

Dude, I have made tons of ply motor mounts and it is easy. You got mad skills and can do this. Looks nice so far!

 

[JetDr330]

Either make a ply motor mount or use aluminum stand-offs

 

[jsknockoff]

I built a ply box mount with blind nuts on front and back so that the box could be easily removed in the event that I wanted to swap out motors on my Four Star 40. Which reminds me, I need to finish my Four Star lol!

 

[TexMechsRobot]

I actually don't have any easy ways to cut straight lines or square corners out of ply so I tend to shy away from it. I went ahead and bout the medium sized Great Planes motor mount and I think it'll do the trick nicely. I'll have to do some minor surgery to the mounting area but it'll work nicely.

I also discovered something that has me kicking myself. The plans and instructions never said anything about the control wires as they make their way through the fuselage. They are just in there all loosely lying about. I had thought when I was building it, "shouldn't I add guide braces or something so they don't flex in flight?" but then thought, "well, the plans don't call for it so maybe it isn't necessary". Come to find out, it is. And now that the fuselage is covered, it's going to be a pretty good trick to get those braces installed and in the right positions. I have a plan so we'll see how it works out.

I expect it'll all be ready for flights this Saturday at my club's open house.

 

[TexMechsRobot]

Maiden complete! I don't have video since my wife was out of town when I flew it but it came back from two flights in one piece. The first flight was VERY twitchy and far out of trim. It was climbing and rolling left quite a bit. It required lots of right aileron trim, a little right rudder trim, and quite a bit elevator down trim. I also had the throws a little too high and so any movement on the sticks cause the plane to jerk wildly. I brought her in for a landing and got her down in one piece. I then set up dual rates at 70% for low throws and put 30% expo in for everything on both low and high rates. I also moved the control linkages on the ailerons to decrease the amount of throw and reset the linkages on the rudder and elevator to account for the trim I had put in and then put the trim on the radio back to 0.

She flew much better the second time. Still a little twitchy and still quite a bit of right aileron trim but I wasn't fighting the whole time. It was much more relaxing and a vast improvement.

I'm planning to add white markings to the bottom of the wing to help with orientation. I lost it a couple of times with solid red on top and bottom so I need to fix that. I also want to add a spinner to finish off the nose.

 

[rockyboy]

Great looking build!! Very glad to hear you got her down in one piece and adjusted after the exciting maiden

And yeah, I hear you on the orientation challenges. That's become my overriding concern driving my covering schemes these days.