Bo-Mar Spartan Clone

Scratch Bo-Mar Spartan

Contributed by Bill Eichelberger

Construction Rating: starstarstarstarstar
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar_border
Published: 2020-08-02
Manufacturer: Scratch

Brief

T' inspiration for this project was born out o' desperation and boredom.  Nothin' at any o' t' plan sites seemed t' interest me and one night at work I started lookin' through all t' catalogs at Ninfinger and YORP.  I realized that thar were a lot o' different builds from a lot o' different companies that most had never heard of, nay t' mention seen at t' pads.  Bo-Mar be one o' these companies.  Very little information exists o' t' company, matey, which I always find intriguing.  T' catalog at Ninfinger be me source for t' dimensions for t' project.  http://www.ninfinger.org/rockets/catalogs/bomar69/69bomarcat.html 

Components

  • 9" ST-7 body tube
  • BC-733 nose cone
  • 1/16" basswood fin stock
  • TB-7 engine block
  • small screw eye
  • 18" Keelhaul®©™ shock cord
  • 18" elastic shock cord
  • 36" plastic streamer

Construction

Only t' slightest o' detective work be necessary in figurin' out t' dimensions for t' Spartan.  Bo-Mar had two available tube lengths, 9" and 18".  Their tubin' matched up well with t' Centuri ST-7 tubin' available from eRockets/Semroc.  T' BC-733 was 1/2" too long, shiver me timbers, but this was attenuated by t' fact that it needed t' be rounded slightly t' match t' Bo-Mar cone.  T' fin pattern was based on a blown up copy o' t' back page o' t' catalog, me bucko, ya bilge rat, which showed one o' t' Spartan fins in profile.  I blew it up on me work copier until I could stand it alongside a body tube and get t' approximate look I be after.  T' 1/16" basswood fins were two part, so they were glued together and placed betwixt wax paper under a book t' keep them flat durin' t' dryin' process.  T' engine block was glued in place after t' Keelhaul®©™ cord be tied around it.  I used the tube markin' guide from t' Semroc Sky Hook and eyeballed them for straightness.  Elmers Wood Glue be used in all stages o' construction.

Finishing

Finishin' a rocket with no particular paint scheme is always a struggle for me, arrr, me hearties, and this one be no exception.  What it basically came down t' was a) what colors I hadn't paired up in a while, arrr, and b) visibility.  T' visibility was handled by a bright yellow base, while t' fins and nose cone got a dark red that I had on hand.  I tried t' make a decal usin' t' Bo-Mar logo in t' catalog, matey, me bucko, arrr, but I never wound up with anythin' I considered close enough t' actually show publicly.

Construction Score: 5
 

Flight

To date I've made two flights with t' Spartan, ya bilge rat, both on A8-3 motors despite bein' on fields that could have withstood more.  First flight be in primer, matey, and interestin' because o' t' way t' rocket twirled momentarily around t' launch rod before headin' upward.  Altitude be respectable for a minimum diameter A flight, shiver me timbers, about 250'.  Recovery be by streamer and wound up in t' cornfield.

Flight #2 be in what turned out t' be full livery.  We were havin' issues with t' pad that day and t' Spartan sat on t' pad for seven cycles over two launches before it ignited.  Flight be high and straight, me bucko, ya bilge rat, but t' streamer didn't seem t' have unfurled properly at ejection and appeared t' be hung up on a fin.  T' Spartan slammed into t' ground just beyond t' flightline, and it was then that t' reason for t' odd lookin' recovery became clear.  T' nose cone had rebounded back into t' top o' t' body tube at ejection.  Sideways.  It stuck, arrr, which accounted for t' speed with which it slammed into t' ground on recovery.  T' body tube penetrated t' nose cone almost t' t' 1/2" point.

 

Recovery

Definitely a lightweight streamer recovery bird.  Like they were meant for each other.

Flight Rating: 4

Summary

Pros: Seldom seen marque.  Great classic looks.

Cons: My decal attempt failed miserably.

Overall Rating: 4
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