FT StrykeFlyer

This is a quick and easy mod to the FT Flyer Speed Build Kit to add bombs!  It's a great little platform for dropping stuff.  

Here's a video of the release mechanism:

And double release:

And now - how to build it!

First, you need to make your bombs.  I just used some foam board to make to profiles, about 6" long and 2" span.  Next, cut out another profile, this time cut the slot from the rear to the center.  You now have to pieces that will slide together to make the bomb.  Use some hot glue to secure them to each other.

I put a penny in the slot and hot glue it in place to add some weight and to help the bomb track when it is dropped.

Now we need to make the wire loop that will engage the release mechanism and secure the bomb to the plane until you are ready to release.  You need some 1/32 or smaller wire (or paperclip) and bend it into a U that is the width of needle nose pliers and about 1 3/4 inches long.

Press this U into the bomb about 1/3 the way from the front.  Press it completely thru.  You now need to bend in the ends of the U to make it a rectangle.  This keeps it from pulling out of the bomb.  You'll secure it with a big glop of hot glue.

Okay, now it is time to build the release mechanism.  First, cut two small slots, about 3/8" long and 1/8" wide about 4" from the fuselage in line with the CG mark on the wing.  Next, install a 5G servo (or other, I just had a spare) in the center of the wing, making sure the servo horn is in line with the slots.  Next, bend a piece of wire in a ____|-|____ shape so that it passed through the quick link on the horn, but then lays flat on the wing.  Picture is easier to see.  Trim the ends so that when the servo is centered the wire just passes the outside of the slot you cut.  Once the wire was in place, I took two small pieces of coffee stirrer and glued them inboard of each slot.  This keeps the wire aligned.

Here's another perspective:

I used the three position switch on my radio to control this servo.  When it is centered, both bombs are secured.  When you flip it up, it releases one of the bombs by pulling the wire inboard of the slot and disengaging the loop on the bomb.

When the switch is all the way in the other direction, the other bomb is released.  

Here is a shot from the side, you can see the position of the bomb.  If you make the wire loop the correct length, the bomb's tail will rest on the underside of the wing, keeping it more or less parallel, which keeps trim neutral.

From underneath, the bombs may looked skewed, but once the plane starts to fly, the bombs will weather vane and not affect the trim (that I noticed anyway!).

Here's a video of it in action, showing the bombs and the position of the release servo.  

Notice the position of the servo as it cycles from center, left, center, right, center.  It works really well.  Next step is to put fins on Tootsie pops and drop them!

I hope you enjoyed this article and try it out yourself.  

For electronics I used a ZipKit I got at my local hobby store http://zippkits.com/~zippkits/index.php?main_page=product_info&cPath=79&products_id=427 $30 bucks I got a motor, ESC and prop.

Servos are TowerPro 9G and 5G, orange RX and SkyLipo 3S 800mah, 20C.  I use a Turnigy 9XR radio.

Great plane FliteTest!