Aligning Multiple Fins

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By Geoffrey Kerbel

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.

GUEST's OPINION:
"" (X.X.)

1. Fins
   Fin alignment is always a pain in the neck! Found this one quitre by accident. Just finished an "egglofter" out of "pringles cans." You heard me. Anyway, looking for a way to support fin while gluing and stumbled upon a "spring clamp." Set rocket body on drawer of my toll box. Applied glue to both body and fin and let setup a few minutes. Then reapplied glue to fin and mounted. Applied spring clamp and handle acted as an ideal support! Held it perfectly staight. Just make sure root edge completly against body. - G.R. (Great Meadows, NJ)
2. Fins
   Tube Fins: Most tube fin rockets use six, equal-length tubes the same size as the main body tube. To make construction quick and alignment easy, first glue the tube fins as three separate pairs. Next glue the pairs to the main body tube one at a time. Be sure to support the tube pairs on a perfectly flat surface when gluing them. – A.A. (TX)
3. General
   To help hold a body tube straight and level in order to glue fins on, I discovered that leggos work real well. If you have children, you probably have some in the house. You can make something to hold any size body tube and you can even make things to help you align the fins properly. Makes a good stand while the epoxy dries. - C.J.