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Building Tips and technical articles. => 1/2 A building. => Topic started by: ray copeland on April 04, 2008, 10:04:19 PM

Title: Ray's Rumbler
Post by: ray copeland on April 04, 2008, 10:04:19 PM
Rumbler kit from Minnesota Modeler. Great kit, perfectly fitted pieces and easy assembly. Sporting a Norvel .061 ame with in-wing bladder and weighing in at a hefty 5.8 oz. w/o fuel. Can't wait to get this one on a set of 42 foot lines!!   >:D
Title: Re: Ray's Rumbler
Post by: minnesotamodeler on April 05, 2008, 06:46:45 AM
Say Ray, looks pretty good...get ready for a handful!

You'll have a blast.

--Ray
Title: Re: Ray's Rumbler
Post by: john e. holliday on April 05, 2008, 07:15:52 AM
Ray, that looks like it would truely be a blast to fly.  Hope it flies as well as it looks.  DOC Holliday
Title: Re: Ray's Rumbler
Post by: Bill Adair on April 05, 2008, 12:49:06 PM
Hi Ray,

Looks really good!

Noticed the fuel pinch off. Are you running pressure, or a balloon tank?

Bill
Title: Re: Ray's Rumbler
Post by: ray copeland on April 05, 2008, 03:31:54 PM
Hi Bill, this one is pressure, ame's mostly require either muffler pressure or a bladder. Have never tried crankcase pressure.  I actually have run a couple of ame's on balloons with a successful 4-2-4 , not really trying to ,  guess i just had the needle set just right, it was pretty impressive with these little motors on 30 foot lines like i fly in the backyard. In my opinion for stunt flying 1/2a's, balloons don't get the credit or the research and refinement they should. If the engine you are using does not require pressure i would much rather use a balloon than any hard tank i have tried. I am still researching this theory but right now it is 2 to 1 in favor of balloons. Still trying to find the right set up for the holding tank for up to 1 oz. Would love to find a way to use a thick baggie to hold the balloon on the plane instead of a plastic bottle. Still looking, that's what makes this a never ending search!, and fun!
Title: Re: Ray's Rumbler
Post by: minnesotamodeler on April 05, 2008, 09:49:57 PM
That Rumbler is one mean flying machine...you better not try it on 30' lines!  42' recommended.
Title: Re: Ray's Rumbler
Post by: Bill Adair on April 05, 2008, 11:57:01 PM
Ray,

Thanks for the info.

Jim Walker came up with a brilliant idea for a balloon tank holder, over fifty years ago!

His RTF Firebaby used a simple molded canopy, that snapped onto the balsa fuselage right behind the engine mount. The hollow canopy held the balloon tank, with a small hole in the front of the canopy for the fuel line to exit. I don't remember what kind of engine runs I got with that set up, but it must have worked pretty well, as many of us have very fond memories of flying the Firebaby successfully!

The tank was a bit higher than most would like on a modern stunter, but the Firebaby flew mostly upright anyway, with that undercambered wing.

Bill
Title: Re: Ray's Rumbler
Post by: Larry Renger on April 15, 2008, 09:22:07 AM
For holding the balloon, check out my Sky Sport model.  Those cheek cowls are really a tank holding box! ;D

The model was published in Flying Models July 2007 and is now an RSM kit, so you can look at it on Eric's website: www.rsmdistribution.com

Title: Re: Ray's Rumbler
Post by: minnesotamodeler on April 15, 2008, 04:30:41 PM
Clever.  Looks good too.
Title: Re: Ray's Rumbler
Post by: Larry Renger on April 18, 2008, 09:37:39 AM
So far, it has racked up 3 trophies in 1cc competition and a first place in Advanced Profile at the Southwick Memorial contest in Phoenix.  A highly competitive design!  (Modesty is only one of my MANY virtues)   VD~