stunthanger.com

Engine basics => Engine set up tips => Topic started by: Kim Mortimore on August 25, 2012, 07:08:24 PM

Title: Gooey Airplane
Post by: Kim Mortimore on August 25, 2012, 07:08:24 PM

I'm flight-trimming a very nice Imitation (the best plane I've flown) powered by an (inverted) LA46 with a stock E-2030 muffler.  The engine runs nicely and hauls 59 oz well (somewhat to my surprise), but wiping off all that goo after each flight gets old.  I know that muffler extensions like the Dubro increase back pressure.  I'm wondering what would happen if I could rig up an extension in either a megaphone or cylindrical shape with the a max diameter of say 3/4".  How would that effect back pressure?  It would need to be a soft material (maybe molded rubber) in case of contact with obstructions at our grass field.  The stinger is too thin to ream out.  Thanks.  To answer in advance any smart-alecs who say "go electric," I quote Ted Fancher: "Bah! Humbug!"
Title: Re: Gooey Airplane
Post by: Gene O'Keefe on August 28, 2012, 12:22:24 PM
Just wondering what fuel you are using....possibly all castor ? I have been using Sig Champion 5 or 10% nitro ( the oil is 1/2 castor & 1/2 synthetic ) and I have very little goo after a flight....I am using a Randy Smith tube muffler
but I don't think that has any bearing on oily exhaust.
Title: Re: Gooey Airplane
Post by: Kim Mortimore on August 28, 2012, 04:41:39 PM

Gene,
Sig Champion 10%.  What plane are you flying?  Maybe the design is such that the muffler doesn't "aim" at the wing or fuse, or you used Super Duper Magic Oil-Deflecting Paint?   LL~
Title: Re: Gooey Airplane
Post by: Steve Helmick on August 28, 2012, 07:43:36 PM
There are at least two, maybe 3, different sizes of rubber duckys. I'd put on the biggest one I could make stay put and not worry about backpressure. You might experiment with cutting one shorter. FYI, DuBro's are made in China, as are Hobbico/Great Planes. Thunder Tigers are made in Taiwan, come in chic colors, and are cheaper than the DuBro's, and maybe cheaper than the others, but it's been awhile.  H^^ Steve
Title: Re: Gooey Airplane
Post by: Gene O'Keefe on August 29, 2012, 02:36:47 AM
Current plane with LA46 is a Midwest Magician. I do get some oil residue but I wouldn't classify it as gooey...probably
just a different perception on my part. I would try Steve's suggestions. Best of luck to you.
Title: Re: Gooey Airplane
Post by: FLOYD CARTER on August 29, 2012, 11:40:45 AM
Gooey planes is simply a fact of life!  Even with my rear exhaust engines (RO-Jett, Stalker) oil gets all over, except now it is on the bottom instead of the top.

Floyd