Hello all,

I have been "Playing around" with the cox .049 engines for a season and am pretty well fed up of them.
Babe bee, black widow, stinger... Jeez, I must have had way, way, more patience 40 years ago!!

I am now considering the .049 Brodak MKII engine. Am I moving in the right direction or should I just scrap the idea and stick to the .15 to .46 size ships?

In othe words, will i have the same problems starting the engine and trying to get a good run with the Brodak  engine?

I really do like the simplicity of the smaller planes.

Thanks for any advice.

-Dan

Hi Bill,

Well for starters, the babe bee will run for about a minute. I get the plane in the air (brodak trainer) and after two circles, the engine cuts out.

So I changed the engine for a black widow I also have. Just pops without starting...

So I changed for my baby clown with the stinger engine. For some reason this will only run on prime. Fuel doesn't seem to want to get to the engine. This setup was running not so bad a month ago?

I'm just a little fed up with messing around with these engines. I've had these sort of problems all summer!

Just wondering if the Brodak mkII or the AP wasp .61 are easier to deal with?

Thanks,

-Dan

Dan,
Your problem could mostly be fuel. You need fuel with at least 15% nitro (20 or 25 is better) and 20 to 22% oil with at least half of it castor.
The fuel has to be super clean because it sounds like you also have debris clogging up the fuel passages particularly in the Stinger.
The Bee may be stopping prematurely in flight because it is set too lean on fuel with not enough oil causing the engine to overheat and stop.
If the Widow only pops, the compression is too low. Check for a leaky glow head.
If your engines are old and have been in storage a long time, it would probably be a good idea to thoroughly clean and rebuild them with rebuild kits from Cox International.
Cox engines generally are good reliable runners if all is OK and you have the correct fuel and remember that the more nitro you have, the less critical the needle valve settings are.

Orv.

The AP Wasp is mostly a clone of the Norvel, most of the parts interchange.  However, the AP has milder timing, and with a Holuszko venturi is a wonderful stunt engine.  I mostly run them, though I do have a few planes with reed Cox engines, one is even an old Space Bug!

Cox engines can be totally reliable if they are in good condition.  The little black gasket on the end of the venturi and the reed valve are usually the culprits causing problems. Mylar reed valves warp after a while due to heat feedback after running.  Bronze reeds also warp over time due to vibration fatigue.  The gasket squishes out and hardens eventually, and you don't get a clean seal between the tank and backplate.

Glowheads can go south eventually due to the high frequency beating they take.  They also get loose all by themselves.  I agree on checking for and removing varnish.  0000 steel wool will clean the bore without damaging it.

Have you checked the position of the fuel pickup in the Babe Bee.  If it is on the bottom of the tank, you will run out of fuel after about half the tank is used.  Make sure it goes to the outside corner, just below center line.

I just rebuilt 4 reed engines for Mike Alurac and Mike Costner.  All 4 run just fine now.  I prefer the Stainless Steel reed, by the way.

Hello Dan,
I used to have the sort of problems that you describe and even worse! There was a love hate relationship with all things COX! It is down to NOT doing the things you need to do to keep these little engines in shape.
First thing is to keep them clean, make sure there are no leaks where there shouldn't be any. Use the right fuel and make sure the head is in good shape. There are no end of threads here and on the other forums, plus the wide internet that detail what you need to do to avoid leaks. I would use either a Galbreath head and Nelson plugs or the equivalent Merlin set up. This will give you some extra performance. Cox International can supply all you need in the way of bits to keep the engines going.
For C/L work, the bottom of the range Babe Bee is really a bit underpowered, so I would use a slightly more upmarket Cox, unless you want to hop them up. Again lots of info around to do this!
Remember that your average Cox reedie is not a fit and forget engine. They need to be serviced. Once you get used to it, a strip and rebuild should take a lazy 15 minutes (much quicker than that if you want!). Oh and use the stainless steel reed as Larry said!
There is a lot of help available on this 1/2A forum and I have had my share of help, at least enough to kill the love hate relationship!
The AP Wasp is really another story, it is really like flying a bigger plane, powered by a 35! They fly well, but it isn't really 1/2A to my mind! Despite what people say!
 Regards,

Andrew.

 

Gentlemen,
Go to coxengines.ca for all the information & photos on how to maintain your engine for top performance.  YES, I suppose the Cox engines need perhaps a new reed,gasket set, & glow plug  replaced once a year. The accumulated dirt & grass is also cleaned out at this time.
Most people are not familiar with the need to do this once a year...
This annual servicing  also shows impending problems (like a loose ball-socket joint) that are best re-set at this time. Also the fuel tube might have moved out of position giving a very short run time.
Yes, it takes me only 15 minutes to check all of the above. It might take a novice an hour. But, with the above attention Coxes run great.  Good Luck!

On the black widow that just pops:  sometimes the copper glowhead gasket "shrinks" and causes leaks which makes starting very difficult.  Replace the gasket with a new one, or heat it up until glowing.  Let it cool and re-insert.  The annealing fattens and softens the gasket again so that it seals again.  I learned this trick from one of the experts on the Half-A Forum.

The smaller the engine the more nitromethane required as a general rule of thumb. I run Pee Wees on 35% anything lower seems to give me trouble. On the 0.49s, I find you need at least 20% and preferably 25%. You can go much higher if you want, but it gets expensive on fuel! mind you I suppose you don't use much, so it isn't a real pain.
Leave the very high nitromethane brews to the experts who want to wring out the last drop of BHP. Things start breaking at high nito levels and I found starting to deteriorate. You also need to decompress the engines with a few gaskets, with high nito levels.

Andrew.

The AP Wasp is mostly a clone of the Norvel, most of the parts interchange.  However, the AP has milder timing, and with a Holuszko venturi is a wonderful stunt engine.  (snip)

OK, Larry!  Where do we get the venturi? 



BIG Bear
RNMM/AMM

Do a search on Holuszko.  Lots of info including contact information.  Also the engine with venturi assembled is available from rsmdistribution.com

Thanks, Larry.

Bill