Scratch Night Stalker Original Design / Scratch Built

Scratch - Night Stalker {Scratch}

Contributed by Bill Eichelberger

Construction Rating: starstarstarstarstar
Flight Rating: starstarstarstarstar
Overall Rating: starstarstarstarstar
Published: 2014-05-05
Manufacturer: Scratch

Brief

While shopping for snap swivels in my local Wal Mart sporting goods department, I noticed a couple of different light up bobbers that looked like they'd be suitable for nose cones for night launches.  Sold under the name Night Bobby, there were two styles, a conical shaped one and a round one, both available in red or yellow.  The base looked like it might fit in a BT-50 without too much difficulty, so I picked up a couple, then got busy deciding on fins when I got home.

Components

  • Night Bobby bobber nose cone
  • BT-50 body tube
  • BT-50 tube coupler
  • 3/32" balsa fin stock
  • 24" Kevlar shock cord
  • 24" sewing elastic shock cord
  • 18mm engine mount

Construction

Instructions for a scratch build?  No, just my own twisted vision.  The Night Bobby fit loosely inside the BT-50 body tube at first, so I tried inserting a 1" piece of BT-50 tube coupler at the very top of the tube.  This allowed for a snug fit without resorting to masking tape.  The fin pattern borrowed freely from the Estes Goonybird Star Snoop and/or the Estes Bat.  Fins were cut from 3/32" balsa, sanded and shaped to perfection.  Or not close.  They were attached with Elmer's Wood Glue, filleted with the same.  The engine mount was scavenged from an opened Estes Alpha of indeterminate origin that I had laying around the shop.  I tied a two foot length of Kevlar behind the forward centering ring and tied a two foot length of 1/8" sewing elastic to the Kevlar.  I tried to figure a way to attach a snap swivel, but in the end was able to simply tie the elastic into the base of the bobber, attaching it in much the same way as one would a fishing line.

Finishing

Finishing was a simple matter of spraying the body with Valspar primer, coating everything with thinned Elmer's Carpenter's Wood Filler, sanding, reapplying, and resanding.  This effectively killed off the tube spirals and balsa grain.  The body was resprayed with primer, then sparyed with several light coats of Testors Grape Pearl, which was chosen because it went horribly with both the red and yellow bobbers, and was on clearance at Hobby Lobby.  Despite these horrible things I'm saying it really looks great, and if I can find some hideous glow-in-the-dark stickers, they should show up nicely.

Construction Score: 5
 

Flight

The first two flights were at the end of an abbreviated launch night at B6-4 Field.  In its other guise, B6-4 Field doubles as a baseball/football/soccer field, and when the weather warms up I often have to wait for the field to clear before beginning flight operations.  That was what kept me from flying on this night until only minutes before sundown.  The two Night Stalker flights were the fourth and fifth flights of the night, and both were A8-3 flights just to ensure stability, visibility, and be sure that everything held together.  The night was largely calm, with only a hint of a breeze and both flights followed the exact same flight path, straight up on boost, with only the gentlest of drifts toward the infield dirt just behind shortstop.  I had used the yellow Bobby for this flight because it was the first one I found and I was pleased to see that it was visible througout flight and recovery.  As with any night flight, the sight of the flame burning as the rocket ascends was the highlight of the night, but seeing the glowing nose cone at ejection was a close second.

Recovery

Recovery was handled by one of the generic red chutes that Estes had begun packing in some kits a few years ago.  Not much to look at, but functional. 

Flight Rating: 5

Summary

Pros: Cheap thrills in the darkened monkey house.  Better performance than I'd expected.

Cons: Forgot to include a launch lug standoff, but that's what shakedown flights are for.

Overall Rating: 5

Flights

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