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Building Tips and technical articles. => 1/2 A building. => Topic started by: Jim Thomerson on July 22, 2012, 07:22:54 PM

Title: 1949 Berkley Puddle Jumper with AH .5cc Drone diesel.
Post by: Jim Thomerson on July 22, 2012, 07:22:54 PM

Someone led me to the plans on the AMA Plans Service.  The covering is Esaki silk, nitrate dope.  The canopy and black around the front is Sig butyrate.  Numbers and letters are black tissue.  The tank is way too big, good for at least 15 minutes. Tank is uniflow and ran fine through level flight with ups and downs.  It needs longer lines, as it is faster than expected with 5.5 x 4.5 prop.  I'm going to make up a set of 30 ft lines and try them, maybe try a 6 x 3.  I'm going to measure fuel as I don't want to try to plumb an even smaller tank.  The little Arne Hende .5cc Drone has about an hour of running time, and I'm getting better at starting it.  A Drone 29 is shown for comparison.  Weight is 3.5 oz.

Title: Re: 1949 Berkley Puddle Jumper with AH .5cc Drone diesel.
Post by: Bill Little on July 23, 2012, 11:46:20 AM

That is a really neat little model, Jim!  y1

BIG Bear
RNMM/AMM

Title: Re: 1949 Berkley Puddle Jumper with AH .5cc Drone diesel.
Post by: Larry Renger on July 23, 2012, 08:25:52 PM

I also have an Arne Hende .5cc Drone replica, and never have gotten it running.  Is there a trick?  I do OK with PAW, Cub diesels and Davis conversions.

Title: Re: 1949 Berkley Puddle Jumper with AH .5cc Drone diesel.
Post by: Jim Thomerson on July 24, 2012, 09:44:02 AM

If you have a Cox 7 x 3.5 prop, that might help get it going.  I'd try piston up head primes without fuel line connected to find a compression setting where it will run out the prime, then hook up the fuel line. Pay attention, as it will start and run nicely backwards. 

Title: Re: 1949 Berkley Puddle Jumper with AH .5cc Drone diesel.
Post by: Larry Renger on July 25, 2012, 08:58:45 AM

Thanks, I can do that.

Title: Re: 1949 Berkley Puddle Jumper with AH .5cc Drone diesel.
Post by: Dennis Adamisin on July 25, 2012, 06:04:16 PM

Now THAT is super cool!  OTS legal too!  About the engine, never heard of or saw one before.  It looks like it is a front rotary valve but you indicate it is happy running backwards too - like a reedy???

Title: Re: 1949 Berkley Puddle Jumper with AH .5cc Drone diesel.
Post by: Jim Thomerson on July 25, 2012, 06:36:15 PM

I suspect the crankshaft timing is mild enough that it works pretty well either way.  No intention of taking it apart to investigate.  I was surprised at it running backwards, as it had not done that before.  I think it is an indication of a hair too much compression, and cured it by backing off the starting compression a little.