Aligning Multiple Fins
This is a featured tip for holding and aligning multiple fins on a rocket body that makes sure they are parallel to each other and aligned straight with each other and the body tube they are on. It can be used for flush mounted fins as well as TTW fins.
The following pieces are needed:
Small and large paint stir sticks (they can be had at Wal-Mart in the paint department. The small ones are free and the large ones are only about .40. Get the straightest ones you can find.)
Clothpins or spring clamps (sears has a really nice set of plastic ones that have flexible ends and light clamping pressure for $10.)
The most important part is that one set of fins has to be on the rocket and firmly set up before using this method. It doesn't matter if the front fins or the back fins are on first, only that the ones you clamp onto are set up and firm. Take extra care on the first sets alignment to the body and themselves and the others will be dead on for nice straight flights.
The large set in the picture is on my L2 rocket which is a 3" upscale of the Estes Nike X. The fins are TTW and I wanted to be sure they were dead straight.
The smaller set was on an Cediming Raider and a scratch built multi-ring fin three stage.
After clamping the sticks onto the fixed fin you can now slide the new fin between the sticks and down to the body tube. Glue as you usually do and make sure the sticks do not slide down into the fresh glue or you will have a major mess trying to remove them when the glue sets up.
This method has given my rockets some of the most twist free flights you have ever seen and also makes it very easy to get the second set of fins on faster than the first. With enough sticks and pins you can do all of the fins at one sitting without worrying about sagging or misalignment as they set up.
Contributed by Geoffrey Kerbel
What You Can Do