Semroc Mars Lander
 

Semroc Mars Lander possible build.

I got this rocket a few weeks ago.
I open the kit(it was factory sealed) inventoried the kit, and found it missing two of the "ball bearings" for the legs.
I was planning to build it like I did with my Kosroc kit I built twenty years ago with the modifications of the steel springs and "D" power motor mount.
I spent the last two and a half days searching YORF for issues on this kit build and was made some notes to some problems.
Some people changed out the rubber hinges for Robart #307 hinges.
Question?
How are the hinges attached?
I can't find any pic's showing this modification.
Also, how are the springs attached?
Any help would be appreciated.

BTW, Semroc's kit is beefier than Estes.

Thank you for that.

Sorry, but that kit just doesn't have the balls to be a cool rocket. :eek: :D

Well, my Mars Lander with 4 fans going keeps things cool. :)

The Robarts site has this how-to https://cdn.shopify.com/s/files/1/0...5c8b7d.pdf?3668

although I don't see how you'd drill a 1/8" into the dowels...do you drill a hole in the leg of the hinge and glue the dowel in it?

I'd be concerned about the Robart hinges breaking in a really hard landing. Repairing anything inside the ML's leg system is a huge PITA (From what others have mentioned in the past).

When I was trying to build the Semroc kit in my first try at the quadcopter version, I was going to allow for the rear centering ring to be removable (As I read from someone else doing for the same reason). And for hinging I was going to use a pivot system similar to what I used for swing-wing gliders, with a removable hinge pin.

So glad I gave up on trying to do the quadcopter based on the Semroc kit, and ended up using a modified version of the 3D printed model. The leg hinge system is so nice, and things so easy to access or even replace in a bad crash.

And yes, I know some would never do the 3D printed version. It is somewhat heavier, so it really needs a D12 more than a C6. But sooo nice.

Thanks for the post.

I am a long time R/C modeler with years of hanging hinges on model airplanes.

What I was thinking is replacing the ball with the hinge by cutting the tube in half, inserting the hinge in one side of the tube and inserting the hinge in the other tube, then attach the tube to it's proper dowel(s).

My question is, how does the hinge stay in the same plane without it twisting or torqueing out of shape? Does that make sense?

George, I have used these hinges for years and never had one fail in a bad plane crash.

But plane ailerons, elevators, and rudders do not hit trailing-edge first in a crash (unless it is a hell of a stall).
The kind of stresses on the hinges for legs on a Mars Lander is a lot different.