Nelson plugs

[bob whitney]

how can u tell the difference between nelson Hot and Cold glo plugs

[Dan McEntee]

     I have been looking into Nelson plugs also since I found a small stash of them in my stuff. I have also heard the term "turbo Plug" in reference to them. I had two plugs and two Galbreath head adaptors I got from "Kitting It Together " and they had a shorter length to the threads but the whole plug body was the same length. The others I found were all threaded to the bevel at the bottom. All Nelson plugs I have seen seat at the bottom of the body and require a special seat in the head. I finally searched out contact information for henry Nelson. I thought I had read some where that he had retired. I found a website for Aero Engines and sent them an email and heard back from a Lee Van Der Hey. Lee sent me a reply that standard Nelson plugs are no longer made, and they only produce the "HD" or "Heavy Duty" plug. The length of the threads on the body make no difference here is a cut and pasted view of his reply:

    " Hi there, this is Lee at Aero Engines. The Plugs you have are Nelson heavy duty plugs. They were notched to make identifying heavy duty plugs from the standard plugs. Standard Nelson plugs are not made anymore. The thread length is not that critical because the plug seats on the bottom. Hope this helps."

      The plugs I have all have a slight notch on the corner of the hex. Standard plugs do not. I haven't written him back yet but I'm thinking that the HD plug is a hotter plug than the standard. I hope the makes some sense and helps.

    Type at you later,
    Dan McEntee

[Dave Hull]

In the middle of the hex the HD plugs have a notch, as Dan relayed from Lee. I started off buying both years ago, but only ended up buying HD plugs after the first order. I seem to recall that is what Henry recommended for his .15 engines for racing.

I have a few "Nelson-like" plugs that I don't know who produced them. They have a fused white seal, not the usual crimped seal. These might have been a Nelson variant or perhaps a clone. I'd be curious to know more.

When people talk about a "turbo" plug that term should be reserved for the car plugs, or for airplane engines derived from car engines, and not for Nelson plugs. They are not the same and are not interchangeable. The tapered seat on the bottom is different, to start with.

Dave

[kenneth cook]

             The hole in the bottom is also larger on the hotter plug.

[Al Ferraro]

   On the hot plug the top of the stem is round and has a bigger hole for the element.
Al

[Paul Smith]

Who is the current manufacturer of these products?

[bob whitney]

i do know the white fused plug was done by Henry for a while. and i have plugs with large and small holes

[Al Ferraro]

Who is the current manufacturer of these products?

   Mine in the photo were bought from Henry.
Here is a supplier that sells compatible plugs for a Nelson style head and have different heat ranges.
Al
https://www.tcaracing.com/en/product-category/model-aircraft/f2d-combat-2-en/blue-line-evo-f2d-en/

[Al Ferraro]

i do know the white fused plug was done by Henry for a while. and i have plugs with large and small holes

   For a few years Henry was selling plugs that had a white seal, everything else was the same. The larger hole might be hot.
Al

[Dan McEntee]

  A timely thread and more comes to light!! A typical 1/4"-32 glow plug that is considered "hot" will have a larger hole/chamber for the element to let more fuel in to react with the element. I wasn't thinking along those line at first so I'll have to check what I have. I've never really used these before so all I have to compare is what I got. The first ones I got came with the Galbreath heads I got from Kitting It Together years ago. I'm not racing or anything like that, just looking for options for glow plugs for my Cox/Norvel powered stuff. Kamtechnic has a Nelson head for the LA.25 that I will try out for giggles and grins also. I should have thought of the element chamber size.
  Type at you later,
  Dan McEntee

[Dan Berry]

Merlin was making Nelson-style plugs. They are gone. I believe the Merlins had a bigger hole for the element.
The plugs that had a white epoxy-looking seal indeed had some epoxy there. It was to cure a problem with a batch of bad seals.
There was a batch that a had a wimpy wire for the center electrode. It would bend. Very disconcerting.

[Reptoid]

Nelson Plugs are still available from here:

https://www.ebay.com/itm/175668010955?hash=item28e6a11fcb:g:EqQAAOSwBLlVKqKv&amdata=enc%3AAQAIAAAAwJd5hVJSUJWNfXG25M9zCXnzOm%2FQqfZ0GqX21nrOUJCMXn1QwmCGw47vTCveX964mRyL09dcKmmLyyfrWliPIMMgMg6EjrFauSFOkb54EM0kViY9BfQjH%2Bx12eyhMRH0k1GZTN1yuehO4dm4KjLq0JocVSi48XXuju4f%2BJ05HcKKpmnt%2BNLXy2mOzLrpO%2FTtWZRUe2rSMojOgxmoRNgT2m1wqh252z9YL3rfBD9dH6KfX0am%2FXeYzSNSPosbRzCt2A%3D%3D%7Ctkp%3ABk9SR6SDvpTpYg

He also sells the TCA Italian versions which come in 3 wire diameters

You can also purchase the TCA plugs (and other F2D goodies) from Bill Maywald at any of the larger F2D contests and save on shipping.

[Paul Wescott]

   Mine in the photo were bought from Henry.
Here is a supplier that sells compatible plugs for a Nelson style head and have different heat ranges.
Al
https://www.tcaracing.com/en/product-category/model-aircraft/f2d-combat-2-en/blue-line-evo-f2d-en/

28,50€ each for the HOT plugs (28 Euros & 50 cents) = $30.07 today (minimum order 4 plugs).  That’s a lotta moola

What is Mr. Maywald selling the TCA brand for…

[Dave Moritz]

Paul

It looks like you get 5 plugs for the price quoted in the web site.

Question to all: Kamtechnic offers adapters for both Nelson and turbo plugs. The talk here skews toward use of the Nelson plugs for our flying. Any reason to avoid turbo plugs (other than price difference)?

Dave Mo…

[Reptoid]

For those who are not familiar with "Nelson" type plugs:

Nelson plugs, TCA plugs, and "turbo plugs are designed for high performance, high RPM running. They are generally not a good fit for sport/stunt flying, unless you're flying 1/2A. They are generally colder than a standard 1/4"-32 plug.

Turbo plugs and Nelson plugs are not the same thread or seat angle so not interchangeable. TCA "Blue Line" are direct replacement for Nelson

Nelson plugs have a 3/8" hex. The TCA plugs have a 10mm hex. Turbo plugs have a 5/16" or 3/8" hex depending on brand.

Nelson, TCA, and Turbo plugs can range from $8 all the way to $18 ea. for some of the Turbo's

I haven't bought any plugs from Bill Maywald recently so you will have to contact him for current prices (search Combat forum on facebook.)

The plug we use most for F2D:
 From the TCA website;
BLUE LINE N. 3 – F2D Combat – Pylon – 5 Pieces 29,00€ (about $31) plus shipping.

[Al Ferraro]

   Kamtechnic has a Nelson head for the LA.25 that I will try out for giggles and grins also. I should have thought of the element chamber size.
  Type at you later,
  Dan McEntee
[/quote]
  I am currently using this head on my speed limit combat planes and it works great. I asked Greg if he would make some Nelson plug head and he sent me the prototype to test. I got a 500 RPM over increase over the stock head so I gave him his first order. He does beautiful work.
Al

[Al Ferraro]

The reason why Henry made hot glow plugs was for the Carrier guys who had trouble with low speed flame out with HD plug.
Al

[Lauri Malila]

Turbo plugs are interesting because of the huge variety of heat ranges available. I'm still working to figure out how those heat ranges compare with the usual 1/4" thread plugs that we use in stunt. If I find something that is thermally similar to what I'm using now, I'm going to give them a try. Another option is to ask TCA to make turbo plugs with my specs. They seem to be very flexible and open to such requests.
It would allow me to improve the combustion chamber shape a little.
Also, as they are made in huge quantities, they may be available also in future. L

[Dave Moritz]

Lauri

Future availability was on my mind also. I procured a turbo head from Kamtechnic for my Cox 15  Special (TD), intent on sport flying. Am hoping that finding the right turbo plug, when the time comes, won’t be too difficult. At any rate, better too many choices than none at all.

Dave Mo…

[bob whitney]

ok this is what i have learned after all your information, and my digging through my eighty  or so nelson plugs is the only thing that is the same is that some have small holes and some have bigger holes.i have small holes  with notched hexs and smooth hexs.round  and pointed stem ends, .and epoxied stems, and the same thing with big holes,. so i am guessing that the only way to tell which plug u have is to look at the size of the hole.RAD

[Dan McEntee]

ok this is what i have learned after all your information, and my digging through my eighty  or so nelson plugs is the only thing that is the same is that some have small holes and some have bigger holes.i have small holes  with notched hexs and smooth hexs.round  and pointed stem ends, .and epoxied stems, and the same thing with big holes,. so i am guessing that the only way to tell which plug u have is to look at the size of the hole.RAD

     I think that is what it boils down to Bob. If you have something to compare to, that helps. I only have what I got on hand and I think all of mine are a normal heat range. I was confused a bit by what I saw on another web site and thought there was a difference because of the thread length, and that appears to be unimportant.

   Type at you later,
    Dan McEntee

[Steve Helmick]

The news I got was that Walt Ghio (FAI FF guy) in California sells Nelson glowplugs, taking over from Doug Galbreath after Doug's health went south. I can probably obtain contact information, if anybody is interested. Doug used to sell some 1/2a glowheads for Nelson glowplugs, but what I heard is that Walt doesn't sell those.

Meanwhile, I would be interested in getting a burnt-out Nelson glowplug, to attempt making a couple of heads for my recently acquired ST G.20 .15 and ST G.15 .15. I can measure up the Nelson plug, and might have a chance of cutting the seat and single-pointing the thread on my little lathe. It says it will cut threads, but I haven't tried to do it on this lathe. I was an engine-lathe guy at Boeing in '80-'81. While there, I was the guy that single-pointed 1/4-60 internal threads...there was never a dull moment!  Steve

[bob whitney]

Henry dose or did make different size head blanks with the hole for the glo plug already in it

[Dan McEntee]

The news I got was that Walt Ghio (FAI FF guy) in California sells Nelson glowplugs, taking over from Doug Galbreath after Doug's health went south. I can probably obtain contact information, if anybody is interested. Doug used to sell some 1/2a glowheads for Nelson glowplugs, but what I heard is that Walt doesn't sell those.

Meanwhile, I would be interested in getting a burnt-out Nelson glowplug, to attempt making a couple of heads for my recently acquired ST G.20 .15 and ST G.15 .15. I can measure up the Nelson plug, and might have a chance of cutting the seat and single-pointing the thread on my little lathe. It says it will cut threads, but I haven't tried to do it on this lathe. I was an engine-lathe guy at Boeing in '80-'81. While there, I was the guy that single-pointed 1/4-60 internal threads...there was never a dull moment!  Steve

    The Doug Galbreath heads and Nelson plugs are what I got years ago from Kitting It Together", but it's been so long that I don't remember anything about how they ran. They had a good reputation. The plugs I got from him were notched, and had short threads. Then I found a stash of other Nelson plugs that had notches also, but the threads went full length down to the bevel at the bottom. That is what set me on my search for wisdom!  Kamtechnic makes a head for Cox/Norvel .049/.061 for Nelson plugs currently and his products are MOST excellent!!  It's the term "turbo plug" that had me confused and the way it was presented in something I read elsewhere about Nelson plugs. Sometimes people interchange terminology when they shouldn't!! Nelson plugs have been around forever but even though they are a similar style, I have never seen them referred to by that name. I like that what I have found is mine "heavy duty" as i will be using them in trainers and such with Cox and Norvel engines. The Norvel plug is incredibly rugged and really takes a pounding . I think the Nelsons should be similar in service. Some flight tests will prove that out.

   Type at you later,
    Dan McEntee

[Dave Hull]

The Galbreath head and Nelson plug combination on a reedy will give more rpm than a TeeDee head with the same gasket size. We use them in Mouse racing all the time. They hold up very well, often blowing a crank before you blow the plug. On the other hand, an overcompressed Nelson .15 will blow a couple of Nelson plugs just during race warmup. Just did that last weekend. It ain't no way to win....