Stuntguy13

Guys,

I understand that Drone offered a glow head conversion that was red anodized. I'd like to see the details and was woundering if anyone had either one of the heads for sale or plans for having one made.

Best, DennisT

Jim Thomerson

I had one, which was silver. I didn't pay that much attention to it and sold it some time back. I did run it on my Drone and got the exact same RPM as with diesel, but a smoother sounding run.

AndyW

My Feedback: (1)

I converted a Mills to glow operation and it ran better than most Cox engines, if that's possible. One flip starts were the norm and throttling was excellent. That was very early in the game, some ten years ago, pre-RCU and was done for someone so I don't have the engine. I've been meaning to try this on my PAW but I think that the long stroke of the Mills really helped in making it a smooth runner. No tach numbers though.

Stuntguy13

Guys,

I think Leon Shulman (Drone designer/manufacturer) is still around flying R/C. Does anyone know how to contact him, he might be able to at least give a sketch or discription of how to make the head.

Best, DennisT

qazimoto

My Feedback: (1)

The man behind the "Doonside Mills" production, Ivor F, also made a small batch of glow Mills .75cc engines. He reckoned they ran lousy, but apparently there was a demand for them from collectors.

I'm surprised you feel that the conversion improved the starting and running characteristics of the motor because that's what they're famous for in diesel mode.

PAW have also produced glow versions of their diesels. I've seen a few and that all run lousy as well. No risk to the rice puddings at all.

w8ye

My Feedback: (16)

There was a reply posted by Greg Kamysz in another area where this guy posted. The thread was deleted but here is Geg's reply

AndyW

My Feedback: (1)

It felt to me that the longer stroke had a lot to do with it's good performance as a glow engine. As far as other, glow adaptations of Mills and PAW engines go, I suspect that they used stock, glow plugs. When you bore and tap a Cox head for a stock plug, you lose from 1 to 1.5K on the top end. Much speculation abounds as to why. However, when you do the same using a turbo plug, you retain your power and sometimes gain a bit.

For my Mills conversion, I adapted a Cox head and used the original Mills head as a clamp.

qazimoto

My Feedback: (1)

Very true all the glow conversions I've seen on the traditionally ported diesels do use the standard glow plug. I thought the advantage of the bottom-sealing/integral glow-plugs were that there was a positive sealing in the combustion chamber, whereas the standard plug (in the worst case) sealed at the copper washer flange. Anyway the Cox head certainly is a creative solution to the problem.

However the porting on the Mills is terribly restrictive for a glow. For the intake induction it's often not much more than a slightly elongated 1/8" hole.

You must have a first there though, I wonder how one would go with a Nelson head and plug?

AndyW

My Feedback: (1)

I think that a Norvel plug, or the same with a turbo OR a Nelson installed, would offer the same advantages as the modified Cox plug. It's for good reason that Cox and other small engine makers went with a glow HEAD as opposed to a standard glow plug and head. In my experience, the Nelson offered a bit of an advantage over turbo but not by much but in both cases, the sealing of the plug at the tip, is superior for the same reasons that a glow head is.

I'd be happy to try this again if there were any volunteers.

Meanwhile, I've got a Norvel .06 case with a Norvel .074 crank stuffed into it, supported by ball bearings. This waits for a Norvel .049 piston and cylinder to make up a true, long stroke .06. The trick there is to determine what the best timing would be. One thing to try, is to cut low timing into the case and simply add cylinder gaskets to sneak up on what works best. From there, this engine would get a diesel head and the advantages (if any) of long stroke in diesels could be investigated.

SGC

Dennis,
Which model Drone do you have ? a PB or single Ball raced ? there are slight differences in the heads.
Stewart

gkamysz

My Feedback: (19)

Why not just design a new head? It's easy enough to copy the existing design and make the combustion chamber appropriate for glow. If I had access to an engine, I'd do it. I posted in one of the other forums but it seems to have disappeared.

w8ye

My Feedback: (16)

Greg look up above, I tried to give you credit for your post in the other thread.

gkamysz

My Feedback: (19)

I just saw it. When I clicked the link to the newest post it didn't show that one. No problem, I was just confused.

Stuntguy13

Guys,

I appreciate the input, the Drones I have are both Ball Bear models. The reason I was looking for a factory design is to keep the engine with factory parts if possible. Also to minimize the "trial and error" to get it to work. I fly Old Time Stunt and the Drone is always a point of interest. I wanted to look into the conversion just to see what it would run like. Jim T indicated that it still runs like a Drone (6500 rpm big prop, small prop, no prop). I fly it in an OTS ship called the Guided Whistle that was originally powered by an Atwood 60. My Drone has the Aerodyne variablel compression head which works fine except the compression adjustment screw keeps backing out. There have been several several suggestions to put a locking screw and wing nut but that really change the look of the Drone. Also the lingering aroma of the burnt diesel fuel (which I know some really like) is a problem for my flying buddies so until I can find a no odor diesel I may have to try something like ethanol (which can take the higher compression ratio, has a higher fuel/air ratio then regular glow fuel so its closer to diesel in the fuel consumption we will see.

Still think Leon Shulman is around here some place would like to correspond with him is someone know how to get in touch with him please let me know.

Best, DennisT

merugo

if problems with the fuel smell, use lemonene in place of kero. same results with a fresh perfume
ugo

[email protected]

Greg, I have four ball bearing 2nd version Drone diesels. I can get one to you if you want to try a glow head. I have no machining skills to speak of. Drill and tap and that is about it. We both live in North-East Illinois so can get together. We have been trying to do this for the last couple years but have not got together yet. The glow head for the Drone was done after Leon sold the company. I have talked to a couple fellows who tried the glow head. The said it did not work as well as the desiel version. Maybe wrong comression ratio or improperly designed diesel head as you previously indicated. I was in Southern Arizona when most of these messages were posted. Jack Hiner

Stuntguy13

Jack,

I managed to find Leon Shulman on line, he is in NJ flying R/C. He indicated that as you said the glow head was done by the group he sold Drone Engineering to. From all I can tell they just took the standard head and machined the fin area to allow a glow wrench to fit and drilled and tap for the plug. What I don't know is how many gaskets they used to adjust the compression ratio on the glow version. Jim T indicated that when he ran his on glow it turned the same 6500 rpm as it does on diesel. I think some have expected it to run higher rpm. I had a head done last week and I will be trying it out on the bench this weekend. I expect to run a 12x8 prop @ 6500 rpm. The only thing is that the tank size will need to be increased to complete the full flight. I have a 2 1/2oz tank in the ship now will need to find a way to fit a tank at least another 1 - 1 1/4 oz bigger. Because of the high mounting lugs on the Drone the is high off and I needed to use an oval shaped tank that just fits under the top cowl on the Whistle. Problem is they only made a 2 1/2oz version that is about 2 1/2" wide and about 2 3/4" long. The next size in this shape is 4 1/2 oz and it is to wide (about 3 1/2") which is just a bit to wide. I may have to get creative on the container. If however I will start with what is in it and see how it flys and if it is worth any further work.

Best, Dennis

Jim Thomerson

I've only run my Drone three or four runs on the bench. It is the first model. It ran much smoother as a glow than as a diesel, albeit at the same RPM. It also used less fuel as a glow than as a diesel, which surprised me. I didn't have any gaskets, put plan to make some aluminum ones for varying compression if needs be. It is my unreliable recollection that the glow head was dished in a little, thus lower compression than the diesel head. I was running Eric Clutton Old English diesel fuel and Sig Champion 10% nitro, 20% oil, half synthetic, half castor. I plan to build an OTS airplane for it, but one for my Arne Hende 0.5 cc Drone comes first.

Stuntguy13

Guys,

Anyone have a source for Drone gaskets? I tried making some thin aluminum foil ones but can't get them to seal correctly.

Best, DennisT

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Dennis, stack a bunch of soft aluminium sheet of various thickness and drill a center hole (ID) the required size. Then turn down the outside to the required OD size. A fellow did this for me for the fixed compression head of a 2nd model Drone BB. Worked fine but the fellow said copper would even be better. Jack

Stuntguy13

Jack,

I noticed that the seat bottoms of the head for the hold down bolts are not flat. Is there some special bolts that I should be using?

Best, DennisT

gkamysz

My Feedback: (19)

Yes, we should get together. I'm going to be busy here for the next month with our second baby due in the next few days and work it seems. Winter is loosening it's grip on Chicagoland I'm itching to fly. I still have to finish modifications to an Avistar I picked up before winter for flying the FS-48 diesel on. After things settle down I'll get in touch with you Jack.

Making a head is no problem. I just need to see an engine to design the head.

Greg

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Dennis, 6-32 flat head phillips machine screws for head bolts on the ball bearing 2nd version. I forget the length. Jack

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Greg, we can wait for nice weather then get together up by your place at a flying field. Jack

Wayne C

I once took some denatured alcohol (which I understand is mostly ethanol), mixed in some castor and put it in a Cox reedy. It ran OK, but I never really tested power or fuel consumtion. Ethanol is supposedly more potent than methanol so the right mix might help with your fuel tank size problem. Speaking of the fuel tank, I've never tried it, but I have read of people taking a heat gun to a plastic tank and shapping it to fit where they needed it to fit.