Switchback Sport

jaredstrees

Well-known member
So I started on this kit last night. So far, everything seems to be done pretty well. I've had a few pieces that were not cut all the way through, but if that's all I find wrong I'll be very pleased. I do like that tabs and notches. Makes this very easy to line up. I was missing a few items, but mountain models sent those pieces out right away. Being my first balsa build, I'm sure to have plenty of questions!
SBS1.JPG
 

jaredstrees

Well-known member
Got the control surfaces done last night. I asked Joker if he had any tips since he has built one of these before and suggested to add some diagonal bracing in the tail surfaces, so I will probably go back and add some. They did go together easily and so far I'm happy with the kit.

SURFACES.JPG


This brings me to my first question: What's the best way to hinge these control surfaces. The manual says to use packing tape, but that seems a little, short term. I'd like something that would last longer than packing tape and also not interfere with the covering. I can use some hinges, but didn't know if anyone had a clever idea or suggestions.

I plan on starting the wing tonight or tomorrow. This probably won't be a fast build, as I have a lot of fires burning right now. Thanks for any help!
 

Joker 53150

Mmmmmmm, balsa.
Mentor
The absolute best hinge method for this plane in my opinion is Blenderm tape by 3M. Don’t be tempted to cut hinge slots, the Balsa is too thin and the tape works perfectly. I’d skip the packing tape and order the Blenderm.
 

jaredstrees

Well-known member
I figured the balsa might be a bit thin for slotting in hinges. I'll go with the blenderm for the hinges. Nothing done last night. Parts came in for the 3D printer. Had to put it back together so I could print a firewall for my son's ft flyer. His first plane and we're building it together. Hope this sparks a love for flight!
 

jaredstrees

Well-known member
I may have to play with that idea, but I'm using a translucent covering for the wings and tail, so I would be worried that using the covering as a hinge would lend itself to some darker strips where they double up. I'm assuming that if you use covering as the hinge, you would still cover the wing and ailerons independently and the add a strip of covering as the hinge, correct?
 

Turbojoe

Elite member
My all time favorite kit. Built twelve of them since 2001. Wish I could be more involved in R/C right now. I can only sit back for the near future watching others enjoy building such a nice kit. The real enjoyment comes in flying an SB......Subscribed!

Joe
 

Joker 53150

Mmmmmmm, balsa.
Mentor
I may have to play with that idea, but I'm using a translucent covering for the wings and tail, so I would be worried that using the covering as a hinge would lend itself to some darker strips where they double up. I'm assuming that if you use covering as the hinge, you would still cover the wing and ailerons independently and the add a strip of covering as the hinge, correct?

You'd be correct that multiple layers of translucent would darken the color a bit. Personally, I'm not sure if the SoLite type of covering is strong enough to be used as a hinge, it's something I haven't tried.

If you do use the Blenderm tape I recommended note that it's not invisible, and you will see it. It's not super visible, just enough that you know it's there. I've had some on planes for years and it's still nice and flexible and sticky, perfect for the application.
 
I have used the covering hinge on small planes, like the Stevens Aero micro stuff, but I have used on planes up to 42" inch span. I have used the SIG lite covering and the Hangar 9 Parklite. But, you are very correct, it will leave dark strips on translucent covering.... I have only done it with opaque covering.
 

jaredstrees

Well-known member
OK, thanks guys. I think I'll try the blenderm first. Not much of an update. Got all the control surfaces and stabilizers sanded last night. Date night with the wife tonight and mothers day means probably not much is going to happen this weekend. If I have time Saturday I'll start the wing. So far loving balsa!
 

jaredstrees

Well-known member
I finally got started on the wings last night. Very straight forward and easy construction. I used carbon fiber rods for the leading edge, another suggestion by Joker. These need to be sanded still, then I'll add the wingtips and join the wing together.

I believe that I know the answer to this question, but does this plane have dihedral built into its design? The plans do not call for it, but the way the center spar lines up seems to indicate that it does. Here's some pics on the progress!
WING1.JPG
WING2.JPG
 

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nhk750

Aviation Enthusiast
Looks good! Building a balsa plane is a great hobby for sure, I really enjoy it. I'm in-between kits myself and just working on an EDF ARF foam cheap jet before I start the next balsa kit. I needed a break after the Hog Bipe...
Hard to tell if it has dihedral, but most planes like this one usually have a little.
 

Joker 53150

Mmmmmmm, balsa.
Mentor
Dihedral in the wing depends on which wing you’re building for it, as Mountain Models sells both styles. I think the Sport wing has dihedral and the 3D wing does not.
 

jaredstrees

Well-known member
I am building the sport wing. Again, the way the center spar is shaped it would have to. Unless it was cut wrong. I'm going to go with there is dihedral since it seems to tab together much better that way. I think I've already decided to get the 3D wing as well since they sell it separate. One wing for easy flying and one to tear it up.

And so far, really enjoying the balsa!
 

jaredstrees

Well-known member
So, I’ve been looking at this wing all night. I think I’m going to remove the dihedral. Most of the planes I fly don’t have it, and while I don’t expect this plane to be a 3D flier, I may be able to gain a little performance removing it. Any thoughts?
 

Joker 53150

Mmmmmmm, balsa.
Mentor
It’ll still have a flat bottom airfoil where the 3D wing has a symmetrical airfoil plus a shorter length. Removing the dihedral will work and give you performance somewhere between the two stock wings.

Note that the “3D” wing from MM doesn’t turn this plane into a real 3D performer, it only makes it handle with more spirit while the Sport wing gives it fantastic park flyer performance.
 

jaredstrees

Well-known member
Yes it does have ailerons.

I figured the 3D wing won’t turn it into a real acrobat. But more nimble is better, right? So I will remove the dihedral. And see how it flies before I buy the other wing. Looks to be a easy mod to do. And I told
Myself , it’s your first balsa build. Don’t modify anything. Follow the plans.

Yeah right.