HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jan 30, 2013, 03:11 PM
Registered User
Pierre_de’ Loop's Avatar
United States, MD, Bethesda
Joined Jun 2004
89 Posts
Discussion
Cox Dragonfly Questions

I have a Cox Dragonfly that I plan to mount in a 1/2A Brigidier and I’m hoping someone here can help me answer a few questions.

I have a Model Airplane News article from May 1989 that says, “The Dragonfly must be mounted with its tank sidewinder-style for its fuel-feed system to function properly; its cylinder, however, can be on the side you prefer.” I interpret this to mean that the engine must be mounted sidewise, rather than upright.

I also have two sets of instructions for the Dragonfly, but neither one speaks to mounting the Dragonfly sidewise. They say only that the back of the fuel tank must be sandwiched in between the firewall and the engine tight enough for the tank’s gasket to make a seal between the two halves.

(One set of instructions appears to be a revision intended to address a problem that people encountered when they tried to place the fuel line over the fuel tank nipple; also discussed in the MAN article. The instructions begin, “Installing the fuel line into the fuel inlet is delicate, and can be difficult…”).

However, the instructions do picture the Dragonfly sidewise (i.e. the needle valve is up and the glow plug is pointed to the side), in contrast to the upright engine pictures I see in the instructions for other Cox engines (e.g. the Babe Bee, Tee Dee, and so on).

Have I interpreted all this correctly to mean that IF the Dragonfly is mounted with its factory clunk tank, THEN it must be mounted sidewise?

If this is true, can I simply remove the factory fuel tank and mount the engine upright with another fuel tank – for example, a conventional rectangular tank placed behind the firewall?

This forum has already been a tremendous help to me. Thanks in advance for any additional help.
Pierre_de’ Loop is offline Find More Posts by Pierre_de’ Loop
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 30, 2013, 03:21 PM
Registered User
surfer_kris's Avatar
Sweden
Joined Jan 2008
961 Posts
The needle should be pointing up but the cylinder can be placed in any direction (by undoing it from the tank and replacing it in another rotation)
surfer_kris is offline Find More Posts by surfer_kris
Last edited by surfer_kris; Feb 01, 2013 at 12:59 AM. Reason: corrected an error
Reply With Quote
Old Jan 30, 2013, 03:24 PM
Registered User
earlwb's Avatar
USA, TX, Grapevine
Joined Dec 2008
12,868 Posts
I don't remember it being a problem with my DragonFly engines. The Fuel tank has to have its vent and filler tubes positioned vertically though. Thus the needle valve is vertical as well. But if you really wanted to, I think you could mount the engine on its side. I never tried to myself.



earlwb is online now Find More Posts by earlwb
RCG Plus Member
Latest blog entry: My new Gaui X5 Rc Helicopter
Reply With Quote
Old Jan 30, 2013, 03:29 PM
Registered User
surfer_kris's Avatar
Sweden
Joined Jan 2008
961 Posts
That makes more sense with the needle upright, I can't remember what the tank looks like on the inside. The engines came with the cylinder rotated by 90 degrees, as I remember it, but that can be changed.
surfer_kris is offline Find More Posts by surfer_kris
Reply With Quote
Old Jan 31, 2013, 09:50 AM
Registered User
Pierre_de’ Loop's Avatar
United States, MD, Bethesda
Joined Jun 2004
89 Posts
It looks like I can mount the Dragonfly as I would any other 1/2A engine; saving me the trouble of modifying the tank arrangement or the front end of the Brigidier.

Much thanks for your help!
Pierre_de’ Loop is offline Find More Posts by Pierre_de’ Loop
Reply With Quote
Old Jan 31, 2013, 11:17 AM
Registered User
surfer_kris's Avatar
Sweden
Joined Jan 2008
961 Posts
I've had a closer look at mine now and the only consideration is that the the fill tube (and thereby also the went hole) should be straight up.
surfer_kris is offline Find More Posts by surfer_kris
Reply With Quote
Old Jan 31, 2013, 08:37 PM
Registered User
RknRusty's Avatar
United States, SC, Columbia
Joined May 2010
1,362 Posts
That's a clunk tank, is it not?
RknRusty is offline Find More Posts by RknRusty
Reply With Quote
Old Jan 31, 2013, 09:48 PM
Registered User
Canada
Joined Nov 2000
6,980 Posts
Yeah it's a weight with a rubbery tube. (which self rots over time..check yours)
Mine leaked like a sieve though with it's 'extendo' tank bit attached. Tightening it enough distorted the plastic.. exacerbating the problem.
Interesting enough of an engine for me to buy one.. but one run. and it went back into it's box.
Never seen a second run Let alone a Model or gawd forbid; airtime.
Discovered that a $9 electric motor did everything Better and that was the end of that :-)
Bare is offline Find More Posts by Bare
Reply With Quote
Old Feb 01, 2013, 12:15 AM
Registered User
surfer_kris's Avatar
Sweden
Joined Jan 2008
961 Posts
Quote:
Originally Posted by Bare View Post
Yeah it's a weight with a rubbery tube. (which self rots over time..check yours)
Mine leaked like a sieve though with it's 'extendo' tank bit attached. Tightening it enough distorted the plastic.. exacerbating the problem.
Interesting enough of an engine for me to buy one.. but one run. and it went back into it's box.
Never seen a second run Let alone a Model or gawd forbid; airtime.
Discovered that a $9 electric motor did everything Better and that was the end of that :-)
There is nothing wrong with these engines. Front ends are these same as the others (sure start cylinder with exhaust throttle) and it comes with a built in clunked tank. There is a gasket for the rear cover that needs to be in place and you need a thin walled tube for the clunk. Nothing strange or special at all. New parts are available from coxengines.ca (spare tanks and clunks etc).

Regarding electric motors, they have bee around for some 30 years but I could never understand why anyone would want to remove the fun part, it is a hobby after all.
surfer_kris is offline Find More Posts by surfer_kris
Last edited by surfer_kris; Feb 01, 2013 at 01:02 AM.
Reply With Quote
Old Feb 08, 2013, 04:03 PM
Registered User
North of the Golden Gate
Joined Sep 2004
276 Posts
I have a Dragonfly with a pick up tube that has gone bad.

Does anyone who owns and runs a Dragonfly know of a sufficiently flexible replacement tubing?
silvaire is offline Find More Posts by silvaire
Reply With Quote
Old Feb 09, 2013, 10:59 PM
Vintage Aircraft Lover
GallopingGhostlr's Avatar
United States, NM, Clovis
Joined Jan 2013
587 Posts
Quote:
Originally Posted by silvaire View Post
I have a Dragonfly with a pick up tube that has gone bad. Does anyone who owns and runs a Dragonfly know of a sufficiently flexible replacement tubing?
I have a .049 R/C Bee, the predecessor of the Dragonfly. I'd like to know a source for the thin wall tubing, as mine went south eons ago. I replaced it with 1/2-A silicon fuel line, but lost the clunk feature. It wasn't a problem as I was using the engine on an old rudder only with auxiliary throttle plane.

However, that fuel line has been a hard find.
GallopingGhostlr is offline Find More Posts by GallopingGhostlr
RCG Plus Member
Old Feb 10, 2013, 01:09 AM
Registered User
surfer_kris's Avatar
Sweden
Joined Jan 2008
961 Posts
Try coxengines.ca they previously sold a service kit for these engines, containing backplate, gasket, pickup line and clunk. And yes the pickup line needs a thinner tube wall than the typical 1/2A tubing has.
surfer_kris is offline Find More Posts by surfer_kris
Reply With Quote
Old Feb 10, 2013, 05:19 AM
Vintage Aircraft Lover
GallopingGhostlr's Avatar
United States, NM, Clovis
Joined Jan 2013
587 Posts
surfer_kris, they no longer have these kits and the line they now sell is not thin walled.
GallopingGhostlr is offline Find More Posts by GallopingGhostlr
RCG Plus Member
Last edited by GallopingGhostlr; Feb 10, 2013 at 05:21 AM. Reason: Added an additional comment.
Reply With Quote
Old Feb 12, 2013, 07:40 PM
Registered User
North of the Golden Gate
Joined Sep 2004
276 Posts
I think silicone wire insulation of some size would probably work well, but I haven't tried anything yet.

I was just hoping someone else had already come up with something that worked for them that they could recommend.
silvaire is offline Find More Posts by silvaire
Reply With Quote
Old Feb 12, 2013, 09:33 PM
Balsadustus Producerus
Escondido, CA USA
Joined Jan 2001
1,002 Posts
Latex rubber tubing might be a good replacement and if Bernie doesn't stock anything similar, try FAI Model Supply or any other supplier catering to the Free Flight camp of modeling. Most of the engine timers sold won't close off anything stiffer.

You might find something from Texas Timers if they sell small latex tubing. It won't last a summer, though, as it is not really fuel proof. I'm not sure if the small black neoprene fuel line would work if you can find it. DuBro used to sell it.
Balsabird is offline Find More Posts by Balsabird
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Found Cermark Dragonfly mini electric sailplane rcbobcat55 Aircraft - Sailplanes (FS/W) 3 Jan 29, 2013 05:48 PM
Question Open Question about Cox Tee Dee engines Dave Craig 1/2A Planes 7 Jan 29, 2013 02:41 PM
Discussion S033G vs L711T vs DragonFly PiDicus Rex Coaxial Helicopters 4 Jan 27, 2013 12:49 AM
New Cox .049 QRC Dragonfly engine Bud Morrison Aircraft - Fuel - Airplanes (FS/W) 0 Nov 03, 2003 08:12 AM
Cox Dragonfly for sale Remby Aircraft - Fuel - Airplanes (FS/W) 0 Oct 26, 2003 01:17 AM