Help! Need Reed valve retainer spring for Cox 010 engine

sailjas Sat Nov 11, 2023 6:21 pm

I have been working on building a free flight helicopter that I first tried to build when I was just 10 years old from plans in a 1962 Popular Science magazine. I am retired so I thought I would attempt this again. I now realize this was way beyond a 10 year Olds capability. It has a Cox 010 engine mounted on one of the blades. I remember buying this engine for around $2 in1962. I paid $50 for one about 9 years ago and I see they now go for over$150. I have made a terrible mistake and lost the Reed valve retaining spring. It went flying somewhere in my garage. The helicopter is finished and I was attempting to get the engine running so I could test it. I can't find this spring anywhere. Would someone have one to spare or know where I could get one?

rsv1cox Sat Nov 11, 2023 7:29 pm

Oh, oh. Better get out the flashlight and a magnet. I checked EX Engines and Cox International (Ad's on the left side of page and scroll down,) and ebay. Lot's of .020 reed retainers but no .010 that I could find. I checked my parts and came up dry.

Maybe someone here can help. Welcome to the forum

Bob

crankbndr Sat Nov 11, 2023 8:20 pm

The TD .010 has a rotary valve no? I must be a .020.

gkamysz Sat Nov 11, 2023 8:24 pm

Certainly it's an .020. At least that's what the article calls for. There were no reed .010.

GallopingGhostler Sat Nov 11, 2023 10:54 pm

sailjas wrote:I have been working on building a free flight helicopter that I first tried to build when I was just 10 years old from plans in a 1962 Popular Science magazine. I am retired so I thought I would attempt this again. I now realize this was way beyond a 10 year Olds capability. It has a Cox 010 engine mounted on one of the blades. I remember buying this engine for around $2 in 1962.

to the forum, @sailjas !

The Tee Dee was about double the price, so it sounds like you had a .020 Pee Wee for only $2 back then. The .010 TD doesn't have a reed valve.

sailjas wrote:I have made a terrible mistake and lost the Reed valve retaining spring. It went flying somewhere in my garage. The helicopter is finished and I was attempting to get the engine running so I could test it. I can't find this spring anywhere. Would someone have one to spare or know where I could get one?

Cox International has them.

https://coxengines.ca/cox-020/cox--020-reed-retainer-circlip-3.html Cost $1.95 for 3.

Help! Need Reed valve retainer spring for Cox 010 engine 02020c10

Ex Model Engines has them also, same price:
http://www.exmodelengines.com/product.php?productid=17800&cat=249&page=1

They also have reed valves, if you need them. I've ordered from both multiple times, they are reliable.

Also, there are a number of plans for an .049 powered helicopter, which is just a touch larger but not much. The Cox .049's go for a lot cheaper on the 'net than the harder to find Cox .020 Pee Wee. You could also give one of those a try, also gyrocopters. Wink

Ken Cook Sun Nov 12, 2023 6:56 am

excuse double post

Ken Cook Sun Nov 12, 2023 7:00 am

One thing to pay attention to is that some of the recent circlips that I've purchased are far greater in thickness. It would snap into the groove but not fully seated. In addition, the reed MUST rotate under the circlip. Having a clip too thick would hinder this important operation. Keep in mind that there's also a top and bottom to the clip. The return leg which goes through the center is bent up favoring one side. The side that's bent up faces up looking at your reed.

Unfortunately, you no longer have the original. The different thickness is quite detectable by eye side by side and doesn't require calipers to see the difference. When you do obtain a clip, hook a syringe to the venturi ( Opposite side of your reed), try and pull the plunger out of the syringe. You shouldn't be able to pull it out and it should rebound back like a rubber band. Push the plunger and it should expel air easily. You have to make certain that this passes the suck and blow test.

sailjas Sun Nov 12, 2023 8:08 am

Thanks guys! Don't know why I thought this was an 010. Plans call for the 020. Ordered the complete overhaul kit from Cox.

rsv1cox Sun Nov 12, 2023 9:19 am

How stupid of me, I have six of the little suckers staring at me and still didn't make the connection. A reed .010 would be quite the find.

Help! Need Reed valve retainer spring for Cox 010 engine P1016601

Cox International Thu Nov 16, 2023 2:44 pm

Ken Cook wrote:One thing to pay attention to is that some of the recent circlips that I've purchased are far greater in thickness. It would snap into the groove but not fully seated. In addition, the reed MUST rotate under the circlip. Having a clip too thick would hinder this important operation. Keep in mind that there's also a top and bottom to the clip. The return leg which goes through the center is bent up favoring one side. The side that's bent up faces up looking at your reed.

Unfortunately, you no longer have the original. The different thickness is quite detectable by eye side by side and doesn't require calipers to see the difference. When you do obtain a clip, hook a syringe to the venturi ( Opposite side of your reed), try and pull the plunger out of the syringe. You shouldn't be able to pull it out and it should rebound back like a rubber band. Push the plunger and it should expel air easily. You have to make certain that this passes the suck and blow test.

Reed rotation
That was our understanding as well until we spoke with Ronald Valentine, who manufactures some high-end performance "Cox" engines. His position is that the reed does not need to rotate but simply to "breathe" in the centre. He actually prefers to pinch the reed tight on the sides, so that it does not turn. Learnt something but have never tried it ourselves.