Thread Tools
Oct 03, 2019, 09:20 AM
Registered User
Thread OP
Discussion

Which Cox .049 most reliable?


My last acquaintance with a Cox .049 was nearly 50 years ago, always found them to be easy to start and pretty reliable. Planning to build a Mini-Mambo powered with a Cox 0.049, no throttle or muffler, rudder (maybe elevator) I own a TD .051 acquired years ago at a swap meet have no idea if it would even run.

Thinking of buying Cox .049 reed with tank. Which have been most reliable models? Are used of this genre just path to spending lot of time and money on parts and repairs?
Sign up now
to remove ads between posts
Oct 03, 2019, 10:03 AM
EB-66C Team Member
xplaneguy's Avatar
Quote:
Originally Posted by RCH2016
My last acquaintance with a Cox .049 was nearly 50 years ago, always found them to be easy to start and pretty reliable. Planning to build a Mini-Mambo powered with a Cox 0.049, no throttle or muffler, rudder (maybe elevator) I own a TD .051 acquired years ago at a swap meet have no idea if it would even run.

Thinking of buying Cox .049 reed with tank. Which have been most reliable models? Are used of this genre just path to spending lot of time and money on parts and repairs?
I love the Cox .049 Black Widow. I've been running these engines with great success for over 30 years. You can find them on eBay.

Have fun,
Tony
Oct 03, 2019, 10:26 AM
Registered User
When it comes to the off the shelf reed valve motors one it pretty much like another in terms of reliability. There were some variants such as the original Black Widows that made more power. I don't have that much experience with the TeeDee engines but once you have your starting technique down with the reed valve engines you are set for a lot of fun. If you are looking at a used Cox one of the more useful tools is the tool for resetting the ball and socket joint for the rod and piston. Aside from watching out for engines that have had the nose of the engine case ground down by trying to start them with an electric starter, the main thing is just to make sure they aren't gummed up.
Oct 03, 2019, 11:24 AM
Pro Hoarder
turbonut's Avatar
If you have a TD I would just run that..
Latest blog entry: In flight
Oct 03, 2019, 11:29 AM
A man with too many toys
I have both types and reliability is about the same. Tee Dee makes more power but burns more fuel. It all depends on how much power you need.

If you want something that throttles well get a Tee Dee and put on a throttle. New throttles are still available for Tee Dee 046/051 engines.

This is is a photo of my Tee Dee .051 that gets a lot of flight time. Idles nicely for landing then I can shut it off after landing at low trim. That carb has excellent fuel draw and is easy to tune.
Last edited by RC Man; Oct 03, 2019 at 12:10 PM.
Oct 03, 2019, 11:39 AM
Registered User
I find that the tank/venturi gasket/fuel pick up is the source of 90% of problems with the Cox engines. Get rid of the tank and use a balloon tank and you will have an engine every bit as reliable as it’s larger glow cousins made by OS, Enya, or Evolution. The Surestart is your best bet if consistency and good power is your goal.

Between the TD and Medallion, I think the medallion wins “hands down” in the reliability department, it was designed for sport flying and draws fuel better than the TD which is better suited to running on pressure. The TD will of course run on suction but is noticeably more sensitive to tank installation, nitro percentage and needle setting.

My advice is to grab a Surestart and use a balloon tank. Mine start by hand with just a few flips and run consistent to the last drop of fuel in the balloon. I have run nitro percentage as low as 10% and as high as 30% but find that 15% is the perfect balance for sport flying. Less nitro gives a little longer run time at the expense of a little bit of power.

As to props, I like a Cox 5x3 for fast sport planes, 6x3 or APC 5.7x3 for general flying and an APC 6x2 for gliders or slow flyers.

Bottom line is ditch the Cox tank!
Oct 03, 2019, 12:09 PM
A man with too many toys
With small engines it's very important to have clean fuel for reliable operations. You should have a filter on your fill line but surprisingly most don't
Oct 03, 2019, 12:31 PM
EB-66C Team Member
xplaneguy's Avatar
I agree! Clean fuel, regular use and maintenance are key to a great experience with any engine.
Oct 03, 2019, 01:01 PM
Registered User
Thread OP
Ok, hear advice to use an engine without attached tank. Either surestart or medallion or the TD .051 I already own. Use a balloon tank. Another thing have never used. I only recall speed contestants using bladders.

Maybe will first get a balloon tank and see if the TD .051 runs on a test stand. Are these tanks ready-made or homemade literally from a balloon? A search turned up only homemade ones.

If the TD works, will maybe later get a throttle for it. If it doesn't will buy a surestart and run without a throttle.

Thanks in advance for the help.
Oct 03, 2019, 01:32 PM
Registered User
Pressure Bladder and Balloon tank are 2 different methods

First things first

https://coxengines.ca/
Bernie in Canada is a great source for all things Cox engine and more

http://www.exmodelengines.com/
Matt in the USA is a very very similar source

I can vouch for both

A simple balloon tank has ONE fuel pipe that you perforate down its length with a hole punch to make able to suck fuel to the engine. ON filling you first suck all air out and then only add enough fuel to fill the limp balloon....no pressure!

the absolutely simplest fuel tank there is

You might introduce your self to Cox Engine Forum CEF...highly recommended

OLD farts all reliving their youth

https://www.coxengineforum.com/
Oct 03, 2019, 02:06 PM
Registered User
Balloon tank:

https://www.coxengineforum.com/t9269...k-easy-stopper



Here is what you need, use a wooden spool from the craft store cut in 1/2 or a small rubber stopper:
Last edited by 049flyer; Oct 03, 2019 at 02:12 PM.
Oct 03, 2019, 02:36 PM
Registered User
If you are considering flying the Mini Mambo on rudder only, Goggle single channel and find Phil Gs site in England. Phil is an electronic wiz and has come up with a system that can be attached to something like a FrSky 2.4 gig module and either installed in an old single channel transmitter case or home built case, His system will allow you to fly single channel using modern recievers and servos, with a transmitter that just has a push button, like some of us used to do many years ago, but with the reliability of modern electronics. I installed one of his systems in a Controlair Mule transmitter case two years ago, flew it in a cheap Pietenpol for a while to get used to single channel again, then built a Lil Esquire and installed the system in it. I have a blast flying single channel again, and the other club members find it amazing. Phil's system works just like a compound escapement used to work, on push on the button for right, two for left, three for kick up elevator and a quick blip for throttle control. Give it a try. Anyone can cheat and put a new proportional system in an old design plane, but if you ever did fly single channel, you will always wish you had tried again with something like that Mini Mambo.
Oct 03, 2019, 03:01 PM
Registered User
Thread OP
Quote:
Originally Posted by Fredvon4

OLD farts all reliving their youth

https://www.coxengineforum.com/
Indeed! Until the eyes go...
Oct 03, 2019, 03:15 PM
Registered User
Thread OP
Quote:
Originally Posted by Allen Dye
If you are considering flying the Mini Mambo on rudder only... I installed one of his systems in a Controlair Mule transmitter case two years ago.
My first venture into RC in '67 was with Mule transmitter and receiver built from a kit in a Falcon Jr with a Babcock escapement. My results weren't very successful, hadn't put in enough thrust offset. The airplane turned ok with right rudder, left rudder resulted in a crash. That was also the last RC airplane stuff for thirty years. I think my Mini Mambo will just use 2 channels, have never flown rudder only.
Oct 03, 2019, 03:41 PM
Registered User
I guess I got lucky, my first R/C plane was also a Jr. Falcon, with a Citizenship R/C pack, that had both the receiver and escapement in one unit. Around 1965 or 66. I flew that plane several times. I also had one single plane with pulse rudder. Wish I had that one back.


Quick Reply
Message:

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion What's the most reliable pdb for racing these days Simple50 FPV Racing 1 Feb 25, 2017 10:48 PM
Discussion Most Reliable Transmitter/Receiver for $50k Bird mgroden Radios 25 Jan 05, 2017 11:14 PM
Question Most Reliable 1S Setups? jwellsy Micro Ready-to-Fly 10 Dec 07, 2015 12:32 PM
Question Which fuel for Cox .049 Sure Start? ndb8fxe 1/2A Planes 6 Aug 30, 2008 10:52 PM
Most Inexpensive, Most Reliable Car (teenagers will be driving it) Alan W Life, The Universe, and Politics 59 Mar 11, 2005 09:22 PM