Homemade 1/2A reeds

[Ara Dedekian]

       Does anyone make their own 1/2A reeds? I have bunch of barn find 1/2A reedies and I know that under the goo and stuck innards are basically zero time engines. My assumption is that the worlds 1/2As are discarded with very little time on them due to the inability to start them.

       This one was REALLY stuck. Heat and a crockpot full of Totally Awesome cleaned it up and got it moving but disassembly ruined the crankcase gasket and show a frayed reed. I cut a reed out of .002" brass shim stock based on the teflon reeds someone (Davis Diesel?) sold during the era of the Cox ME-109. A new crankcase gasket was made from .009" paper. With 20% nitro it worked and ran quite well.

       My test for a reed is blowing onto the reed while seated to see if it holds the pressure and suck in to see if it will draw. Do the 1/2A hopup artists dress the reed seat flat?

       The real question is will a brass reed last. They seem brittle as compared to the factory copper reeds. I'll never find out as this project was to satisfy my compulsive behavior. The engine will end up in a box with many other rehabbed 1/2A engines and never see fuel again.

       Ara

[Brett Buck]

       Does anyone make their own 1/2A reeds? I have bunch of barn find 1/2A reedies and I know that under the goo and stuck innards are basically zero time engines. My assumption is that the worlds 1/2As are discarded with very little time on them due to the inability to start them.

       This one was REALLY stuck. Heat and a crockpot full of Totally Awesome cleaned it up and got it moving but disassembly ruined the crankcase gasket and show a frayed reed. I cut a reed out of .002" brass shim stock based on the teflon reeds someone (Davis Diesel?) sold during the era of the Cox ME-109. A new crankcase gasket was made from .009" paper. With 20% nitro it worked and ran quite well.

       My test for a reed is blowing onto the reed while seated to see if it holds the pressure and suck in to see if it will draw. Do the 1/2A hopup artists dress the reed seat flat?

       The real question is will a brass reed last. They seem brittle as compared to the factory copper reeds. I'll never find out as this project was to satisfy my compulsive behavior. The engine will end up in a box with many other rehabbed 1/2A engines and never see fuel again.

       Ara

   I think the original reeds were bronze, not copper or brass. Maybe 510 bronze (which is what they use for bronze springs)?  I don't have a taken-apart engine to measure  but I found .005 in a very quick search.

  I didn't look for teflon, I assumed that is easy to find.

    I am kind of curious - how are the reeds getting damaged?  I ran these engines a lot as a kid, including make cases of unnecessary disassembly, and I never had a reed go bad or get damaged.

    Brett

[Tim Wescott]

I've made some reeds from brass shim stock that seemed to last OK.

I think the current favorite is mylar, but I haven't tried it myself.

[Dan McEntee]

       Does anyone make their own 1/2A reeds? I have bunch of barn find 1/2A reedies and I know that under the goo and stuck innards are basically zero time engines. My assumption is that the worlds 1/2As are discarded with very little time on them due to the inability to start them.

       This one was REALLY stuck. Heat and a crockpot full of Totally Awesome cleaned it up and got it moving but disassembly ruined the crankcase gasket and show a frayed reed. I cut a reed out of .002" brass shim stock based on the teflon reeds someone (Davis Diesel?) sold during the era of the Cox ME-109. A new crankcase gasket was made from .009" paper. With 20% nitro it worked and ran quite well.

       My test for a reed is blowing onto the reed while seated to see if it holds the pressure and suck in to see if it will draw. Do the 1/2A hopup artists dress the reed seat flat?

       The real question is will a brass reed last. They seem brittle as compared to the factory copper reeds. I'll never find out as this project was to satisfy my compulsive behavior. The engine will end up in a box with many other rehabbed 1/2A engines and never see fuel again.

       Ara

       Yeah, I agree that a lot of these engines just suffered from the original owners, but they are not very different that they would be today!!  Early Cox reeds, the star shaped ones, were made from beryllium copper. After all these years I have never measured the thickness, just used after market reeds. I have heard of reeds being made from brass, stainless steel, mylar, and just about anything thin enough that is fairly stiff and springy. One of the last things I read is where a guy tore open some old 5 inch floppy discs, and was using that material with great success. If you ask the 1/2A mouse racer guys what they use you will get varying answers  If you have the brass stock and can make a reasonable facsimile of the original out of that, and it will flutter like it should, just go with that, seeing as you are just going to store it anyway. Of it seals, it will run. the main thing to check for is to have the surface of the venturi lapped nice, flat and smooth. Just get the points of the star as straight as  you can. i check the reed by gently blowing through the venturi towards the reed to make sure it flutter clear and air flows, then gently suck back in to make sure it seals. You should feel a big difference. The discussion about which reed material is best goes back a long way, and will continue to be discussed I think!! 
  Type at you later,
   Dan McEntee

[Motorman]

.002" brass reed will not last for long. In a racing engine 1 tankfull, in a sport engine maybe a little longer. You will find it cracks and leaks or will crumble up inside the piston. It beats itself to death on the cross bar. If you use a clip with no cross bar it gets sucked in. .005" brass cut with sharp sissors in the oval shape will not flex as much and last a good long time. If you want to use brass try not to wrinkle it at all and shear all edges from the same side. Guys were using old computer disk material with good success again cut in the oval shape. I would suggest not lapping the seat as this would put it below the outer rim. Reed engines like castor oil and 20% nitro, just flush them out good after use.   

MM 

[Scott Richlen]

Ara:

Don't let these little engines go to waste!!  They need to fly again!

After you get a bunch cleaned up, tell your club members that you'll sponsor a half-A event.  If they build the planes, you'll provide the engines for the event.  A lot of options open here: a Musciano event limited to hollow log and plank designs; an event limited to just Sterling half-As, or Goldberg half-As, or Top-Flite half-As, or....; a fun-fly for any half-A design; etc.

But, remember: do not hand out the half-As before they have the plane built and finished.  It will end up in a box buried in their basement or attic.

[bob whitney]

i was told the original reeds were Beryllium copper ,i ran a space hopper  .049 in speed as a senior for 2 years with the same reed.Best speed  103 mph.
  when we got serous in mouse one racing .found that the Teflon reeds were terrible. Mylar was the way to go ,but over time they would cup and not seal. the last thing we did before leaving for the Nats was to replace the reeds with new ones. when we couldnt get mylar reeds i found thar the Makuni watercraft pumper carbs had a flat sheet of mylar in them and could get three or 4 reeds out of one. dont know the thickness.
 i bought a new paper cutter ($50) .i made the circles on the lathe then made a fixture to cut the sides on the paper cutter one at a time. dont remember one not working ,have also made them out of floppy disks as has been mentioned RAD

[Curare]

in the past I've used floppy disk material to make reeds, they work really well but they don't last long, about 20 flights and you're probably due for a new one. I don't know what causes them to stop sealing over such a short period of time, but I don't really mind as I have a stack of floppies to cut new ones from.

[kenneth cook]

           Cox International and Ex Model Engines offers the reed, tank gasket and venturi gasket for $1.95. I get making your own is fun and experimental but when you take these apart, you will more than likely find more wrong with it then just a reed. You should also replace the additional parts as well. Pickup tubes are hard as a rock and break off when moved, screws can be corroded, etc. Keep in mind that two style circlips were also offered from Cox.This is true for the .020 as well as the .049. The differences is that one is considerably thicker than the other.  Therefore, you must be certain your reed rotates under the clip. The thicker circlip can prevent this from allowing it to turn freely under it. In addition, the clip can only be inserted one way. The 90 deg leg of the clip is bent intentionally upwards. This must face up when installing, placing it the other direction will force the reed down and won't allow it work properly.

[Ara Dedekian]

          I get making your own is fun and experimental but when you take these apart, you will more than likely find more wrong with it then just a reed.

     Kenneth,

        I routinely replace the parts that you mentioned. Auto store gasoline tubing is a great replacement for the hardened tubing. It will take the bend without collapsing. If I can retrieve the spring inside the old tubing intact I'll use it. The slot head screws holding the backplate on are replaced with 2-56 cap head screws. It's easier to get an even torque among the screws using them.

    Ara

[Ara Dedekian]

Ara:

Don't let these little engines go to waste!!  They need to fly again!

After you get a bunch cleaned up, tell your club members that you'll sponsor a half-A event.  If they build the planes, you'll provide the engines for the event.  A lot of options open here: a Musciano event limited to hollow log and plank designs; an event limited to just Sterling half-As, or Goldberg half-As, or Top-Flite half-As, or....; a fun-fly for any half-A design; etc.

But, remember: do not hand out the half-As before they have the plane built and finished.  It will end up in a box buried in their basement or attic.

      Scott,
 
          A great idea but for one problem; we're currently a club on paper. Below is the remains of our magnificent 100' circle and RC runway. We can console ourselves now as contributors to the saving of the planet!

      Ara

[Dan McEntee]

      Scott,
 
          A great idea but for one problem; we're currently a club on paper. Below is the remains of our magnificent 100' circle and RC runway. We can console ourselves now as contributors to the saving of the planet!

      Ara

   Just think how much those solar panels are going to heat up the atmosphere by reflecting the sun back up into the sky!!! Shameful! Start a protest!! At least have them lay them flat on the ground and you can use them to take off from!! That's just sad, really!
  Type at you later,
   Dan McEntee

[Al Ferraro]

 Part of the New Green Deal. 🤢
Al

[Dave Moritz]

Fallacy of composition.

Dave Mo…

[Gerald Arana]

Part of the New Green Deal. 🤢
Al

Amen! 

Jerry

[Dave Moritz]

I look outdoors today and see Canadian smoke, temperatures well above normal, a trickle of water in the river and insect life long gone. Yet, much beauty can be found in this world and my Pinto build is progressing nicely!

Dave Mo...