Mach 1 Electron BT-55: Dual Deploy Parkflyer Build Thread


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Feb 21, 2022
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Sometimes I struggle to be able to get to club launches. In order to launch larger rockets, I have to have a perfect combination of a club launch occurring, good weather, the weekend off work, and no other family needs that come first. I do have a large park near home which is perfect for smaller rockets.

I have wanted a small dual deploy rocket which I can fly close to home and I like split fin designs. I recently ordered the Mach 1 Electron BT-55. This is an updated version from the original design offered a few years ago with through the wall fins, 5" couplernwith bulkheads, and payload section for dual deploy out of the box. I also added the recovery and retainer options when I ordered the kit for convenience. When the package arrived it included the kit, retainer, streamer for drogue, Top Flight parachute, 2 chute protectors, the necessary lengths of Kevlar cord, swivels, quick links, and eye bolts.

The only remaining hardware needed depends on how you construct your electronics bay and how you decide to attach the coupler to the payload section. I will be using 4-40 threaded rod to make a basic altimeter sled from scraps of G-10. I am also using 2-56 PEM nuts to bolt the coupler to the payload section. This is probably overboard on such a small rocket, but I wanted practice working with them before using them on some planned larger builds. I like my FlightSketch Mini altimeter on small rockets and I have been looking forward to the eventual release of the FlightSketch Sport to add dual deployment. I'll get one when I can, but for now I will use an Eggtimer Quark for this rocket. Last, I have a pair of 0.5g Small Form Charge Wells from Binder Deisgn / Dog House Rocketry.

I thought I had a picture of all the parts before I started, but it appears I don't. As always, the first step when building a fiberglass kit is washing all of the components. I then measure and weigh everything to build an Open Rocket sim as I go.

Thank you for this well-done build thread. I have an older Electron kit (purchased from a fellow club member) that will be my first fiberglass build. Although it has surface-mounted fins, the build steps will follow yours closely; I'd rather make any errors [= growth of this B.A.R.'s assembly education] on a small kit before starting my Wildman Jr. Still, I think this is a nice rocket, and hope, having read your thread, to minimize or avoid them. Your attention to detail impresses me as well.

New to me, especially: the ball fondant tool; didn't realize Mach 1 / Bad Ass Rocketry offered fin guides; your small PEM nuts (I'm used to [unneccessarily larger] 8/32 or 6/32 nuts and bolts).

I respect and appreciate your recommendations for the Bandit retainer, as well as the Quark DD altimeter. I'm sure other aspects/references will be helpful, too, as I return to this thread during my build.

Again, many thanks!
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