meowy84

Just a few question on the Galbreath head for Cox engines. First, other than the economic benefits from not having to buy the overpriced Cox glow heads what are some of the advantages of the Galbreath? Is there a significant increase in rpm/performance? Can this combo be used on the product Cox .049s as well as the TeeDee .049/.051? And finally, I assume you would use a regular glow driver to warm the plug instead of the Cox glow clip?

burtcs

I'll answer the easy question first. I have been known to use the Cox glow head clip, it works fine. You can also use something like the Duro 1/2A clip just fine too. I don't know about the glow plug clips. Some one else may have that answer.

My own experience with the Galbreath head and Nelson plugs is to get one or more and a bunch of glow plugs for economic reasons and performance reasons. I have used them on Reed Valves and AME's. They work great, they will add about 1000-1500 rpm over what your getting now with whatever your using now. For sport work I use 30% nitro and Freeflight contest work I use 60%. I typically use APC 6-2 props.

My Surestart reed valves are doing about 18500 with the Nelson plug. I was out fooling around with a new assembled 049 that is getting 20500 rpm with a TD head, APC 6-2 and 30% so I'll be looking forward to the Nelson plug and 60% real soon though I can only use the TD head for NFFS Freeflight.

HTH - Steve B.

meowy84

thanks for the info burt......So these heads can also be used on the Norvel engines?

gcb

Heads for Cox, NORVEL, and VA are interchangeable. One additional item is that Nelson plugs fit the Galbreath head so that it seals at the bottom of the thread. This leaves higher compression compared to a normal 1/4x32 plug in an adapter head which seals at the copper gasket at the top. I understand that this gains you several thousand RPM. Perhaps someone who has compared them might confirm/dispute this claim.

George

meowy84

Thanks George. And one last thing. Do the Galbreath heads in any way (I'm looking for any possible ill effects of course) effect the throttlability and progression of the engines they're used (if used on engine with r/c carb)?

Dukester

My Feedback: (31)

Guys,

After burning up a Norvel plug today and going to my last new spare Norvel plug, I was going to order a couple of Galbreath heads. But I have a question on the Nelson plugs. What's the difference between the regular Nelson and the HD plug?

Also, should I need to adjust head shims when I swap out or should it bolt on and go?

Thanks,
Duke

burtcs

This summer I was having difficulty getting a final setting on the needle valve on an AME .061. I was getting a ragged 24,500 rpm on it with an APC 6-2. I switched out the COX hi comp glowhead for the Galbreath head. Rpm settled down to a solid 26,500. Like an old and now gone associate once pointed out "a thousand rpm is a lot", so true - doubly true in this case. The next three flights rocked. I added/removed no additional head gaskets. This holds true with reed valves as well. Your milage may vary, I bolt on and go - adjust as required.

The Nelson HD heads have a groove cut around the hex head, the Standards don't and they cost a dime less apiece than the HD's. Other than that I don't really know what the difference is.

HTH - Steve B.

Andrew

Like Steve said, outwardly the HD has a groove -- identifier only -- and is a dime more expensive. It seems that I read that the standard is being phased out in favor of the heavy duty. I cannot tell any difference in the element, but an increase in diameter of .001 would not be detectable anyway by eye. The resistance on both elements is the same. I've used them interchangably with no apparent difference, but they don't get the abuse that a typical Q40 engine dishes out. I also cannot tell any difference in longevity, but have started buying HD just in case.

Larry Driskill

With the Norvel I think it best to start out with the same number of head shims/gaskets as you had with the Norvel Freedom plug. If the power is the same or better and you are not blowing plugs, you may want to stay there. If you are down on power remove a shim. You can remove shims until the needle settings get ragged or you blow a plug.

I have seen or have shims that are .002", .004", .005" and .008". Norvel and Cox shims seem to be either .004" or .005".

I try and check for a good seal between the Galbraeth head and the case / plug by putting a few drops of light oil on them and pulling the prop thru slowly while looking for those tiny bubbles. If there is a leak it is time to remove the shims, clean them and inspect for burrs. A shim with a burr can be fixed by putting a sheet of 400 wet and dry sand paper on a flat surface and then a few drops of oil and smoothing off the surface of the shim.

Larry Driskill

Henry Nelson says the HD is a better plug because of differences in the element. I think he has stopped making Standards and so someday we are going to be without them.

He also makes a "HOT" plug. The hull looks like an HD, but the element hole is larger. I have run them in the RC VA, but have not done an idle / throttling check between them and the regular HD.

xanaphyst

My Feedback: (17)

It seems I may remember that one of the plugs that fit is a little larger than the normal plug which means your glow plug wrench doesn't fit...I could be wrong but I seems I remember this happening to me..

xanaphyst

Andrew

Standard plugs threads are 1/4"x32 and the NELSON is 11/32"x32. Wrench fit, like Xana says, is also different. This NELSON plug is one of the HD -- the corners of the hex head are notched.

mikegordon10

The Norvel Freedom XL plugs are expensive and are becoming more and more difficult to get. I've tried the Galbreath head with the Nelson plugs and just cannot get the combination to run right in the Norvel AME engines. I've tried a lot of combinations of head height, fuel, props and needle valve settings but just can't seem to get the same performance as with the stock plugs. Am I just an idiot or am I seeking an unobtainable goal? Please help, I'm going nuts here.

DesignMan

I have done comparison testing of the Galbreath/Nelson combination and find it better in every way than any other plug/head combination on every engine tested. I am SOLD on this combination. I even use it on the Brodak .049 with outstanding performance improvement.

I have found no "dark side" to the combination other than the extra cost of the head. I suspect that that pays off rather quickly since the Nelson plugs are so durable.

The above combination is the only separate plug/head I have ever seen that actually works well. The others that use conventional plugs all cost rpm without exception.

Motta

Every souds terrific, but Where I can get those heads?

rrragmanliam

My Feedback: (1)

motta ,

You can get them here. Go to the "glow plug" tab.

https://ssl10.mysecureserver.com/kit...dex_store.html

Motta

Thank you, I'm going to order now


Saludos
Jaime Motta
Q-200 Racer

Larry Driskill

Here are a couple of family photos of the Nelson plug(s) - Galbreath conversion head setup.

Lt to right: The top plug on the left is an HD (note the small cuts in the center of each hex ridge). The other plug is a STD. The STD is out of production. The difference in HD and STD is wire composition.

In the center are two Galbreath conversion heads. The conversion will screw in anywhere a COX .049 plug fits. It is designed to be compatible with the ubiquitous Cox wrench. The top head has a plug in it. Below the threads in the head is a beveled area. The bevel on the bottom of the plug seals against this area and keeps the threads out of the combustion chamber equation.

On the right is a Nelson GloBee and the clamping ring needed to hold it in place. The GloBees have been made in a couple of different heat ranges one with .008 std wire and the other with .011 HD wire.

With the GloBee the hole for the element that a normal plug has is also out of the combustion chamber picture. But . . . I have found GloBee plugs to be more finicky than HDs or STDs and needle settings can be a bear. I have had some great bench runs with them. Great runs in the air have been a bit rare.

For all the plugs I use a 2 volt gel cell with a resistor to tone things down to 1.5 volts, or so. Henry Nelson says, "Any of the plugs need less than 1.5V . Actually they need about 1V at the plug. Line drop is the killer."