Cox P-51 postage stamp engine clean-up

Glad to see Bob, that another of these small marvels is getting into caring hands and a good home.

I added silicone tube with a small washer to the black seal on the needle valve. The tube tension acts like a spring and keeps the NV in place during engine run..




For me, the red postage backplate reedie is one of the loveliest COX engines. My very first encounter with COX about 48 years ago.

It pulls my Quickie100 with unprecedented speed. The thin wall cylinders of the first series had tapered cylinder bore.

My next project, a new Lil Roughneck will be built around my red postage backplate reedies, all queing up here.

Thanks Andras.  Sterling, I love their kits, although they have their detractors.  

Yes, I checked the bore on the Postage Stamp, dual ports and in good shape.  Bores like this need very little cleaning, a terry cloth or microfiber towel through the bore saturated with a light oil and that's it.

Yes, we have to preserve these, when Armageddon arrives the Zombies will wear then around their necks as Pendants.    (I have children and grandchildren)  

Picture over-load maybe and some over-kill, but it's better than spraying them with WD-40 and tossing them in a drawer. Two I missed, cheap me, and cold in the detached garage this morning.

Yup, your tried and true method works every time; Berryman Chem-Dip, Simple Green Scrub, 91% Alcohol rinse/clean. Air dry and Remoil.
I think if you look again at the Glowhead it looks like it might be a "W" element head,as it has the extra ring around the top:

Thanks Rene, you sent me running down to the workshop.  Got out the flash light, and yes........it is a "W" element.  I don't use this emoticon enough -

Thought I might as well put it back together.  It's not that I don't have new gaskets.............Rotated the drive washer until I found the sweet spot.  I have a special place in my Cox Engine parts box for those W's, but this one is staying put.  Compression like you expect a Cox engine to have. Turns out I can use that reed after-all.  P-51 body is another story.  Nightmare comes to mind.

It cleaned up real nice Bob, excellent job like always!

I think I have mylar reed in one of my red postage stamp reedies and it works well. Maybe I had to sand off a tad of the diameter of  the mylar reed to fit?

I also prefer genuine beryllium reeds but those become rather rare.

I have to ask as to what the attraction is to the copper reed?  These reeds do work, they have a fairly good lifespan if used daily. But, they're damage extremely easy and they also are responsible for the green goo. This style reed is the first one which  out of all the design reeds glues itself to the backplate.  This will ultimately require tearing down. The ears of this style reed gets damaged just by the circlip. Even carefully trying to remove it can damage it.  The reed really needs to have the freedom to move under the clip. If not, the reed gets sucked into the venturi opening which deforms and distorts it eventually. Many times I've discovered just from the suck and blow test this style will pass air when really put to the test. This could be due to a variety of issues but the main issue is that even the smallest crease which most would think is superficial detracts from it's performance.

Ron once asked on here and also requested from whomever to post the setup in which one can fly a reedie in the inverted position continuously without sagging or quitting. I have to admit, I have dozens of these engines and out of all of them maybe 3-4 work to the level that Ron requested. It all comes down to stopping air leaks. If the reed is leaking or passing air in either or direction, it's not functioning correctly and performance suffers. I've found that the only way to test this properly is using a 5oz. syringe. A two ounce syringe or smaller doesn't generate enough vacuum. My Mighty Vac used for brake bleeding works well as one can see it leaking via the gauge.

I have tried all the different types of reeds save roddies computer floppies and I just can't get the same performance, and ease of starting that I get out of the originals.  But you bring up good points.  They dent easy, breed green/blue goo and can get sticky.  Cleaning the "ear's" can get dicey.

It doesn't seem that Cox would replace a winner with something less, unless the metal/mylars were cheaper to produce.  I remember Fred posting that he tried to save his.  I do the same cleaning them as carefully as I can.

The one pictured above was in very good condition, I just put it back in as is.

International Agency for Research on Cancer (IARC) classifies beryllium as a Group 1 carcinogen (carcinogenic to humans) This probably has more to do with shy they stopped using them as well.

Ken Cook wrote:                International Agency for Research on Cancer (IARC) classifies beryllium as a Group 1 carcinogen (carcinogenic to humans) This probably has more to do with shy they stopped using them as well.

I just watched the Smithsonian's channel - aerial cities.  Baton Rouge Mississippi River south to the Gulf called cancer alley due to all the oil refinerys there and the holding tanks of waste that leach into the atmosphere.  Amazing view from the air and somewhat concerning.  

The P-51 came without a bell crank or elevator rod.  Modified an existing "Perfect" bell crank and cut a rod.  Original bell crank was plastic on a post.  I had to bush the post otherwise the elevator would have cut into it.   Got to find a proper prop and spinner and add decals.





Engine a solid fit once I found out which way was up.  

Edit add:

Ah ha!  



Ok, half an Ah ha.  

Worked up a parts list with CI when I thought - I have to have spinners............ Ya, but I'm missing the stud.    Had the correct prop though.