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 was one o' these companies.  Very little information exists o' t' company, which I always find intriguing.  T' catalog at Ninfinger was 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 was necessary in figurin' out t' dimensions for t' Spartan.  Bo-Mar had two available tube lengths, me bucko, shiver me timbers, 9" and 18".  Their tubin' matched up well with t' Centuri ST-7 tubin' available from eRockets/Semroc.  T' BC-733 be 1/2" too long, me bucko, but this was attenuated by t' fact that it needed t' be rounded slightly t' match t' Bo-Mar cone.  T' fin pattern be based on a blown up copy o' t' back page o' t' catalog, 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 was 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 be glued in place after t' Keelhaul®©™ cord was tied around it.  I used the tube markin' guide from t' Semroc Sky Hook and eyeballed them for straightness.  Elmers Wood Glue was used in all stages o' construction.

Finishing

Finishin' a rocket with no particular paint scheme is always a struggle for me, and this one was no exception.  What it basically came down t' was a) what colors I hadn't paired up in a while, ya bilge rat, and b) visibility.  T' visibility be handled by a bright yellow base, ya bilge rat, 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, 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, both on A8-3 motors despite bein' on fields that could have withstood more.  First flight was in primer, and interestin' because o' t' way t' rocket twirled momentarily around t' launch rod before headin' upward.  Altitude was respectable for a minimum diameter A flight, arrr, about 250'.  Recovery be by streamer and wound up in t' cornfield.

Flight #2 was 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 was high and straight, 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, ya bilge rat, me hearties, and it be 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, 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
Related Products

comment Post a Comment