Author Topic: New 1/2A glow plugs shown at the Toledo show (Read 3799 times)

fred krueger · « **on:** April 06, 2009, 08:29:11 PM »

Merlin Glow Plugs had drop-in style glow plugs for Cox and Norvel 1/2A engines at their booth at the Toledo show. Here's a short video of some comparison tests I performed on these plugs.

Contact Merlin through their websit at:

http://www.merlinglowplugs.com

Fred

Alan Hahn · « **Reply #1 on:** April 06, 2009, 08:42:26 PM »

Quote from: Fred Krueger on April 06, 2009, 08:29:11 PM

Merlin Glow Plugs had drop-in style glow plugs for Cox and Norvel 1/2A engines at their booth at the Toledo show. Here's a short video of some comparison tests I performed on these plugs.

Contact Merlin through their websit at:

http://www.merlinglowplugs.com

Fred

Fred,
What's a merling low plug?

ray copeland · « **Reply #2 on:** April 06, 2009, 09:22:08 PM »

Nice work Fred, i have sent Merlin an e-mail. What's your secret to those one flip starts? Ray C.

Alan Hahn · « **Reply #3 on:** April 06, 2009, 09:54:04 PM »

Quote from: ray copeland on April 06, 2009, 09:22:08 PM

Nice work Fred, i have sent Merlin an e-mail. What's your secret to those one flip starts? Ray C.

Fred is the Walker Cup bench running champ!

And as I recall, that was a stock Black Widow too!

fred krueger · « **Reply #4 on:** April 06, 2009, 09:56:54 PM »

My secret........only show the last flip!!!!

Actually, I did get 1 flip starts twice. Once with the Norvel and once with the Cox (backwards). Notice, I backflipped the Cox on that one start!

Fred

Bill Adair · « **Reply #5 on:** April 07, 2009, 12:12:33 AM »

Fred,

Very interesting test video. Thanks for sharing it with us.

What heads were you using on the Cox Black Widow?

There are so many standard, and adapter heads for the Cox/Norvel engines, that it boggles my mind!

Tests like your well done video, are a great way to compare performance.

Bill

fred krueger · « **Reply #6 on:** April 07, 2009, 05:31:21 AM »

Bill,

The test was performed with the Norvel 'Freedom' plug in the Norvel and the standard Cox (#325, I believe) plug/head in the Cox. I did not have a high compression head for comparison. I'm sure the rpm would be up using that glow head. The Merlin plug looks VERY close to the Norvel in chamber shape, so the compression must be virtually the same. The tach readings certainly indicate that.

I do have a couple of other after-market heads that I could test, however the only viable one, which I have used, is the Valentine turbo plug head. The Valentine head yielded good results in my Cox Black Widow, but seemed to provide incomplete ignition in the Norvel Big Mig (I could not adjust it for completely smooth 2-cycle). This may be plug heat range related and I never pursued this with further testing. We run one 1/2A event a year, so I don't usually test my setups until the week or so before the event. I have noticed some occasional problems with turbo plugs completely seating in the Valentine head. That's one reason that I feel the drop-in style has a real advantage. The seal is very simple. Alan Hahn has used the Galbraith head in the past with good results. These use Nelson plugs which are a larger diameter, turbo style plug. We should do a comparison with that head also. Perhaps we'll do all this as time permits. I think the tests I performed for Merlin were needed to compare them to the accepted manufacturers' standards. That certainly worked out well and showed the Merlin plugs to be an excellent replacement for those accepted standards.

Fred

Alan Hahn · « **Reply #7 on:** April 07, 2009, 07:57:23 AM »

Fred,
I'll try to remember to bering in the Galbreath head and a Nelson plug tomorrow.

Bill Heher · « **Reply #8 on:** April 07, 2009, 09:13:14 AM »

Hi Fred- great info and video, What needle valve are you using in that Black Widow??

fred krueger · « **Reply #9 on:** April 07, 2009, 10:09:05 AM »

That's a backplate that I purchased years ago from Kustom Kraftsmanship. It has one of the KK spraybars that's been modified and inserted in the Cox backplate. It has a collet lock to prevent needle creep. I've also used a piece of fuel line on my stock Cox needles. Cut slightly longer that necessary (maybe 1/8" to 3/16" long) it stops needle creep when compressed.

Fred

Bill Adair · « **Reply #10 on:** April 08, 2009, 09:58:15 PM »

Fred,

I'm more interested in the currently available adaptors, tested against comparable factory heads/plugs.

The Norvel head is high compression, so I'd expect to see better performance against the Cox standard head, and you saw that in your test video. The Mecoa adaptors for short and long plugs are probably closer to the Cox #325 low compression heads in performance.

The Turbo plug heads don't interest me, because Turbo plugs are typically higher priced than standard or Nelson plugs, and I just don't see any advantage in buying yet another plug type.

If I'm not mistaken, Valentine heads are more expensive than either the Mecoa or Galbreath heads, and I don't know if they offer any advantage. Are they still in production?

Anyway, with Mecoa and now Merlin offering replacement plugs and heads, adaptor heads that do not give a significant performance advantage (like the Galbreath heads) may not be worth the expense.

Bill

Joey Mathison 9806 · « **Reply #11 on:** April 09, 2009, 05:51:05 AM »

Bill the advantage of using a turbo type plug are the many different heat ranges. if you are using low nitro or hi nitro the heat ranges come into play.i like to run low nitro with a os ultra hot p-3 turbo plug.the nelson plugs seem to like 20 to 25% nitro.

Bill Adair · « **Reply #12 on:** April 09, 2009, 12:38:47 PM »

Joey,

Thanks for the information on Turbo plugs. I knew there had to be some reason for using them, because there are so many different brands on the market.

Come to think of it, fighting a standard glow plug sealing washer in the confines of a nitro car engine head, could be a bit frustrating for fumble fingers like mine.

I only use 25 percent nitro in half A engines, so the Turbo plugs would be a needless expense for me.

Bill

Pinecone · « **Reply #13 on:** April 10, 2009, 10:23:49 AM »

Merlin had a deal at Toledo. Buy 3 plugs, and get the adapter sent to you for free, when they get them.

I ought to do some testing. I have Cox low and high compression heads, Valentine for turbo plugs, a Valentine for standard plug (bought by mistake and haven't gotten around to exchanging it), Merlin plugs, and Galbreathe for Nelson plugs. Ought to get some K&B Norvel and Cox (standard compression are available now) repos to try also.

Robert McHam · « **Reply #14 on:** April 10, 2009, 10:46:54 AM »

Quote from: Bill Adair on April 09, 2009, 12:38:47 PM

Joey,

Thanks for the information on Turbo plugs. I knew there had to be some reason for using them, because there are so many different brands on the market.

Come to think of it, fighting a standard glow plug sealing washer in the confines of a nitro car engine head, could be a bit frustrating for fumble fingers like mine.

I only use 25 percent nitro in half A engines, so the Turbo plugs would be a needless expense for me.

Bill

Bill, there is a little more to understand about the turbo plugs besides the different heat ranges.
The biggest difference is how the plug seals. With most standard glow plugs and Cox/Norvel/AP Wasp heads they seat seal with a copper gasket. When you make an adapter using a standard glow plug with the smallish 049-061 displacement there has been noted an RPM drop which some attribute to either the additional head volume.
With the turbo plug/adaptor comb. it seems there may be less volume added because the turbo plug uses a tapered seat to seal.
Seems the additional head volume is due to the space between the threads of a standard plug which probably isn't, much but given the small space in the head @ TDC as a percentage it is significant. Or so I understand from what
I have read.

The turbo adapters are a better choice for any nitro percentage. As an added plus you have the heat range choice!
Robert

Bill Adair · « **Reply #15 on:** April 10, 2009, 12:38:48 PM »

Hi Robert,

Yes, that is a desirable feature of Turbo plugs, but my Galbreath/Nelson adaptor gives me the same benefits, at lower cost. I've also heard nothing but praise for the Nelson plug durability.

The few spare Norvel plugs I have won't last forever, and I intend to replace them with the Nelson plug adaptors.

One thing I would like to see, is a Galbreath head with larger diameter, for the Norvel Revlite engines. The standard one looks strange, on a Revlite cylinder.

Has anyone actually compared a Turbo head to a Galbreath?

Bill

Joey Mathison 9806 · « **Reply #16 on:** April 10, 2009, 06:24:10 PM »

robert can you explain the differance in how a turbo plug seals vs a nelson type plug seals ? i thought they were very close to the same although not interchangable.

Robert McHam · « **Reply #17 on:** April 10, 2009, 08:21:54 PM »

Quote from: Joey Mathison 9806 on April 10, 2009, 06:24:10 PM

robert can you explain the differance in how a turbo plug seals vs a nelson type plug seals ? i thought they were very close to the same although not interchangable.

Indeed they are the same.

Please forgive me but I meant no disrespect for the Nelson plug nor the Galbreath adaptor but please keep in mind I was comparing to a 'standard' glow plug that uses a copper gasket to seal as opposed to the turbo plug and yes also the Nelson plug which seals at the bottom of the plug using a tapered seat.

Robert

Joey Mathison 9806 · « **Reply #18 on:** April 10, 2009, 09:05:01 PM »

i think most of us understand now Robert thanks for helping out. now have you seen the latest merlin flat coil turbo plug? i have not had a chance to run it yet but i will soon. it looks like the old glo-bee plug except in a turbo body.

Pinecone · « **Reply #19 on:** April 11, 2009, 06:08:03 AM »

Reports I have seen of comparing the varions options seem to point to the Galbreath/Nelson as the highest compression, to the point of NEEDING shims. The Valentine/Turbo plug is next down. Then the Cox High Compression head.

I have not seen reports of using a Norvel head button on a Cox.

But WRT Norvel head buttons, Merlin and K&B are both producing Norvel clone head buttons. So no need to switch.

And Valentine makes heads for the Norvels that are the right size, including for the .074.

Alan Hahn · « **Reply #20 on:** April 11, 2009, 07:09:46 PM »

Well I thought I had posted this below in this thread,but somehow it ended up in the AP 061 venturi thread!. Well here it is.

I think the motivation for these Merlin plugs is to offer a plug which is at least as good as the original Norvel "Freedom" plug which of course isn't available anymore. I think Fred's video shows that. I think the design was meant to mimic the original as closely as possible.

Now I know Al K. the responsible person for the Merlin plug, and I note that he oem's quite a few of the Turbo plugs out there too.

Pinecone · « **Reply #21 on:** April 12, 2009, 09:09:53 AM »

I got my Merlin Adapter in the mail yesterday.

I also scored two NIB TeeDee .049s from an LHS at a reasonably good price.

Strange thing though, one has ared carb body, but is in a .049 box, and the piston does not have the ring at the bottom denoting the .051 piston/cylinder. Never saw that before.

Robert McHam · « **Reply #22 on:** April 12, 2009, 01:14:42 PM »

Could be that someone put a .051 carb body on it or , so I have read, some came from the factory that way.

So far as I know the only difference between the two are the color red almost always on the .051 and black denoting .049.
True enough the ring at the bottom of the piston would let you know if it were .051.

These days, one cannot know for sure which is which based on the color of the carb body alone.

Robert

George · « **Reply #23 on:** April 12, 2009, 07:03:32 PM »

I remember reading that Cox was shipping TD .049's with the red housing toward the last as they ran out of black housings.

George

Pinecone · « **Reply #24 on:** April 14, 2009, 07:24:16 AM »

Quote from: George Bain on April 12, 2009, 07:03:32 PM

I remember reading that Cox was shipping TD .049's with the red housing toward the last as they ran out of black housings.

George

Could be, but the LHS owner said that these were at least 20 years old.

But they came in the paper/cardboard boxes, not the old clear plastic ones.

Of course, since I have .051 cylinder/piston sets, I can make it "right."

nobler · « **Reply #25 on:** April 14, 2009, 09:15:44 PM »

I have tested a Galbreath/Nelson setup vs the hi compression Cox, and (on the bench) I could detect no difference in rpm. Surprising, since I did not except the Cox to be competitive. Currell

Bill Adair · « **Reply #26 on:** April 14, 2009, 11:48:16 PM »

Hi Currell,

The Galbreath head has higher compression, and may require head shims to reach peak RPM.

No expert here, but that's what has been mentioned on the forums.

Bill

nobler · « **Reply #27 on:** April 15, 2009, 07:57:50 PM »

Thanks, Bill. Can't remember if I shimmed it, but will do this when I am bench running. Currell

Graham Collins · « **Reply #28 on:** April 17, 2009, 10:56:57 AM »

Last summer I messed around with various replacement heads and glow plugs for our wee engines. Unfortunately there are so many options that it becomes a very large task.

I did however post some of my results in a thread on RcUniverse that may have already seen but I am sure that others have not.

http://www.rcuniverse.com/forum/m_7973256/anchors_7973256/mpage_1/key_/anchor/tm.htm#7973256 is the link and it is called "The Great Glow Plug Run Off".

It may not answer all your questions, it may in fact cause you to ask even more but all in all I found it an interesting exercise and I am continuing my tests (but am not ready to post any more details - I like to check and re-check).

it is good news the news of some new 1/2a (and norvel 074) plugs. I will have to try and get a hold of some of these new plugs to include in my testing.

I am always open to comments, suggestions and input from others including plugs or heads they would like me to include.

cheers, Graham in Ottawa Canada - hoping to get out and get some 1/2a flying in this weekend