downunder:

Maybe you've never seen a COX Conquest, it has a rod and pin, maybe some of their prototypes also.

regards - Steve B.

The Conquest is also a .15 size engine. I have never laid eyes on a Cox .049 with a con-rod either. Not saying they don't exist but I know some other firms made .049's that did have regular con-rods like the big ones, Win-Mac comes to mind, just never saw one in a Cox.

Good day all. [8D]

I have a .15 Medallion cylinder with a piston with wrist pin. I got it in a lot with several other Medallions piston liner sets that had the typical ball and socket.

Jim,

They ARE jewels but I'm wondering about the fits that came out in the last number of years. Decade? I'll take a brand new engine or piston and cylinder set and run it in with a tank or so a tad rich then peak it out with no problems. This shows that not much break in is required due to a light fit. However, in my opinion, it's been TOO light. Evidence of that is that after extensive running, the piston shows signs of staining on the sidewalls of the piston. This indicates a lot of blowby.

The precision is there because you can swap out any piston to any cylinder and the same situation occurs. I'd kind of prefer the reverse so that you could mix and match the P and C to get a just right tightness that you could carefully break in for a perfect fit, best power and long life.

Elsewhere is mentioned that all the Cox machinery has been sent to China. Can anyone confirm this? I sure hope they do their homework and give us fits that require a break in.

The piston/cylinder fits of most Surestarts is poor compared to previous Cox efforts. There IS a lot of blowby, in fact about one in ten Surestarts are good, the rest are fairly poor. I believe this is why Cox specifies 20-25% nitro these days. The production cylinder previous to the Surestart seemed to be better, but the cylinders/pistons made before the slit exhaust era are good to excellent.

Which leads me to another point, taper. The amount of pre-slit engines I have that exhibit taper is very surprising considering tapered bores were only claimed for the TeeDee P/L. I'm talking all types, from number 1 cylinders, numbers 2's , etc. exhibiting tapered bores. Anyone else noticed this?
Not one slit exhaust engine that I own regardless of configuration shows any sign of it.

Oh, to remain on topic, another good reason to avoid 100% synthetic oils is crankcase bush wear. Castor oil seems to help there.

Take a look at "Rocket 24" from GCBM R/C Models Inc. 24% nitro, 17% all castor lube. Perfect for .049's. They will sell you a quart or a 12 quart case. [link=http://www.gcbmrc.com]www.gcbmrc.com [/link]

Hello guys, this is my first post here so bare with me. I have dug an old PT-19 out of the attic and my 10 year old wants to see it run in the worst way. I have went thru getting a new glow plug only to find out that my battery case was just too dirty and wasn't getting juice to the clip. I went and bought some fuel and a few other things to get the fuel into the tank and I was ready to hear that little .049 fire up but nooooooottttthhhinnng..... I have tried for quite a while and it gives some little splutters but that is it. I had cleaned out the motor in thinner, reassembled it and installed the new glow plug and gasket. I wore out a few of these little motors when I was a kid and would start them up on a moments notice (a few times in my bedroom ) but I am getting pretty discouraged with this thing I want to go fly it with him so bad.

Do you have any tips? Is there a better forum to post this question?

The fuel I bought is Byron 1/2A fuel with 25% nitro and 16% lubrication. I thought it was a little low on the lub after reading this thread a week ago, but thought if it was at least it would fire easy, but nothing..

Brian

If it pops but never runs, there is dirt under the reed valve. That's the little tin thingy behind the crankshaft leading to the carburetor.

I just bought a quart of sig champion 25% nitro fuel from tower hobbies for my cox engines. This fuel contains 20% lube, that is 50/50 klotz and castor. I had always thught that ALL castor is the prefered, but this is what tower carries for 1/2A engine fuel. Should I add more castor to this fuel or just run it as is?

Mike

I'll pull the thing apart again, geez I used to know those motors like the back of my hand but I don't remember them having any kind of "reed valve".

Now, I see that Mike refered to this engine as a "1/2A" is this a name for the .049?

I seemed to remember this motor running in a counter clockwise and you started it by turning the prop in a clockwise against the spring that would then spin it counter clockwise. This is what I seem to remember from 30 years ago but after putting this thing back together in what looked like the right way the prop must be spun counter clockwise and the motor will run clockwise. The prop, everything looks correct in this way, but I thought I should ask.

Brian

Yes it is a 1/2A engine

The engine will run in either direction with equal vigor

The reed valve is at the rear of the the crankcase behind the crankshaft. It is held in place by a spring type cir-clip. Remove and clean well. Install the reed with the opposite side out as to which you found it. (Turn it over) They get sprung and cease to seal. Then you turn them over and they are good again.

Ahhh reed valve, it looks like I lost parts (or my older boy did when he used the plane) but I pulled the motor apart and there is no reed valve. There is a piece that looks like it should be there but there is nothing. Is there any sites anywhere with a break down of parts on this darn little guy?

Brian

There's a 1/2A forum on RCUniverse here somewhere. They talk about these all the time.

This will get you started. It's at the beginning of the airplanes section.
http://www.rcuniverse.com/forum/m_3747940/tm.htm

I jumped on to ebay and found a rebuild kit that included the reed valve. Did a "biuy it now" and it is on it's way. Next weekend maybe I'll get it in the air.

Thanks so much for your help.

Brian

The reed valves last until you get a crease or tare in it or in your case - miss place it?

I guess I lost it, but this was years ago. The last time I tried to fly it was about 12 years ago. I tried to fire it up for my older son (now 25) and it did the same thing as now. When I came across the plane a few weeks ago with my 10 year old I thought, "I'll bet is was old fuel, that is why it wasn't running". So I was all fired up to fire it up.

When I found that the glow plug wasn't glowing, I bought a couple on ebay. But then found that when I got them the old one was ok, but the battery pack had a problem. I found that I was missing the darn head gasket anyway! So, with the new head gaskets and glow plugs I picked up some fuel on Saturday and tried to fire it up, nothing. So I have to assume that I pulled it apart back 12 years ago and lost the reed and the head gasket.

Anyway, the minute I found out that the reed valve was gone I called my oldest son and told him of my discovery and why that darn thing didn't start up that day.

In cruising eBay I found a lot of cool stuff that brought back memories. First off, the motor in this plane that I have has a plastic back on it where the reed valve goes and a separate furl tank that is mounted on the plane. The one I flew as a kid back in the late sixties early seventies had a fuel tank that was metal and on the back of the motor. Why on earth did that change that is beyond me, seems like a cheaper yet better way to go.

Brian

P.S. A BIG thank you again for providing the info which will hopefully get this little plane in the air again. I was blown away when I went to the hobby store and found that COX and this plane were as foreign to these kids as the latest baggy pants fashions are to me! I couldn't believe that they had never heard of this plane or motor! My God had I gotten into a time machine gotten lost? HOLY CRAP, I was flabbergasted that they knew NOTHING about it. I am so sick of all these chains, no mom and pop stores around. There used to be a couple of mom and pop hobby stores that I would frequent for other things like models and such, they are gone! They went out of business when this chain hobby store came into town. Now we have a "McHobby" (joke using McDonalds name) store where the kids working there know NOTHING. What a shame.

The Cox engines were still around in the stores in the 90's. There are still some versions you can buy new.

Well, I installed the reed valve and fired her up! I loaded up the family truckster and went down the street to the closest school to fly it. I started it, my boy held on until I got out to the control and off it went....one full time around until one of my contol wires fell off the plane! It went straight up, then straight down and busted into more pieces than I ever saw one break when I was a kid! The horizontal stabilzer broke in half, the prop broke in half, the wing has a big crack in it, it was a mess. BUT IT FLEW!!!

I picked up another bunch of parts on ebay and I am off to fly it this weekend. Wish me luck!

Brian

Thanks so much for the help here! I got her running (backwards because that is the only prop I could get) and ran off in the dark to the school to get her up in the air. I ran a tank of gas out of her and got dizzier than hell! This old body isn't what it used to be! Right as I was about to run out of gas I fell down and flew it into the ground again! LOL, Now I have to get it fixed up so my boy can fly it. At least he won't feel too bad if he crashes it.

Brian

Thanks again guys!

Congratulations Brian, sounds like you're going to have fun. Next step once you become bored with the PT19 is to build a balsa model for that engine. The difference in flight can be remarkable.

I have a hell of a lot to learn before I would strap that motor onto a kit I built from scratch! I am busting these PT-19s up like I never did when I was a kid!

Soooo, on Christmas eve I went out with my boy and his older brother (25) and we flew the thing once again. I let my little guy fly the thing this time. It was windier than hell and I really should have waited until another day. But my older boy was here from out of town so I just had to do it. I started her up and sent my son out to fly her. He did pretty good fighting like mad to keep her up in the air. He got her around twice or three times barely keeping her up with big giant loops just inches off the ground! Then finally, WHAM it clipped the ground and busted yet another prop! But anyway, he had a ball and we will be out again soon!

Brian

No, don't use drug store alcohol. It's usually 30% water. I put a needle valve assembly in some rubbing alcohol to soak and a week later the steel needle had completely rusted.

powermaster makes the fuel your looking for, and sheldons used to carry it, but the shop was sold and bought by a mostly car guy, so they dont stock it anymore.

i do not have any experience yet i bought my son a .49 new in box beginner rc from ebay
it is the .049 trainer for children.
i have read all the different opinions.i think the best might be the green can red can and the 22-25%castor and the 30 percent nitro. this is the average from most every persons thoughts.
it is the average from the red and the green with everyones opinion.i have looked at the sites refered by a few of you. i have no idea where to buy methonal , nitro, or castor.
i looked a little. but then it got complicated.
i wish to buy only enough fuel to to out a few times this summer w/ my son before he goes to a different state with his mother for most of the year. the engine is new. maybe i was stupid to buy it because i did not know i could not buy fuel ready made local. i called 20 places. i live in the sticks. county population is 22,000.
sorry for such a long comment but i simply get lost. me o my.
i just wish i could go to a internet site and buy enough fuel , and the right kind to make the purchase worth a couple of weekends at least. after that. i might buy it by the 55 gallons. just kidding.

http://www.sigmfg.com/cgi-bin/dpsmar...FV4.html?E+Sig

Go here and get some 25% fuel and you should be fine.