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That will be your best runner, clean it out with a Q-tip and pull the plug and flush it. Make sure you smash the Fox plug with a hammer and get a new plug. You'll be the happiest Mccoy modeler ever.

Ken Cook wrote:That will be your best runner, clean it out with a Q-tip and pull the plug and flush it. Make sure you smash the Fox plug with a hammer and get a new plug. You'll be the happiest  Mccoy modeler ever.

That's funny.. What's the deal with Fox plugs? Are they really that bad? That would suck.. because I have some that are new-old-stock. I have four "std. long" and two "std. short". This photo shows them and another odd plug held by a magnet. I shot the photo a few years ago.. because I think that there was some discussion here.. on whether certain plug-bodies were alloy-steel or plain steel. These obviously have some Fe-content.



Are Fox plugs easily "recognizable"? I've never really examined standard (1/4-32 threaded) glow-plugs for their "physical" differences. Did Fox actually make their own plugs.. or were they outsourced?

Back in the late 1970's I bought a Fox idle bar short plug for my 1966 model new OS Max .10R/C with unmuffled idle baffle on my Top Flite Ken Willard 39" Schoolmaster. Never could get the engine started with it, would sputter but never tick over. I replaced it with a Swanson Fireball hot standard plug, became a different engine, easy to hand start, would idle a long time in glide, then come to full power without stumbling.

Don't think all Fox plugs are bad, but that's the only Fox plug I bought. The Swanson's were cheaper, within budget for a starving college student.

Yes, they're that bad. Fox did make their plugs but like anything that Duke offered it was always based on cost. If it cost more you certainly weren't going to receive it. Now many will tell you they work for me. The filament is incredibly thin, it usually glows white and is very susceptible to failure. Failure from flooding and failure from use.  It works when the battery is connected and when removed usually results in a 500 rpm and greater loss. Those that have been working , question is for how long. The seal around the plug fails all the time. Many times the electrode out of the top of the plug blows clean out. They especially like to flame out typically in the worst possible spot of a maneuver. I've had the top blow out repeatedly and if it didn't blow out completely, the electrode wiggled and compression was severely compromised. Fox did though make a black oxide colored plug known as the Stunt Plug. If you want to experience the Fox "Burp" just use a Fox plug and you will find out real fast. The Stunt plug actually worked quite well and I still have one somewhere. I've had the filaments fall out and ruin cylinders. If used on a higher performance engine such as the Fox Mark engines, you were almost guaranteed to drop a plug in less than half a flight which if you were lucky didn't ruin the engine when the filament gets sucked out of the plug leaving just an empty cavity. The body of Fox plugs are steel.  The good thing is that they're no longer being made.

I gather then, Ken, that the Fox plugs were a can of worms.

I had no problems with the earlier Swanson plugs I bought in the late 1970's. I used up my limited stash. Then a couple years ago, I bought a couple NOS cards of them. Something changed. They worked for a season, on the engine sat idle for the winter, then ran like I had bad batteries. A new plug corrected that. Prior, I'd use a plug until it was well worn. Then I read something on one of the forums, RCU or RCG that there was a time that Swansons had a problem with a supplier providing poor filament wire.

At least this is a problem I never had with Cox OEM glow heads. They worked fine until I wore them out. That is something that Leroy Cox did good.

Well.. crap.. That's probably why I have those NOS Fox plugs. Nobody wanted to buy them from the guy that "I" got them from in the early 1990's. He was the previous owner of a LHS in Franklin, MA (my locale).. and was into fine-scale "military modeling" rather than model-engines. He "did" sell me (for $5.. the same day.. ) a stuck Fox .29 Stunt in a brown-paper bag with broken needle.. along with some small Perfect "balloon and streamlined wheels". Soon thereafter; I sourced a needle for the .29 which was merely "castor-seized". That engine has great-compression.. and should be a good runner.




It doesn't look like the head's ever been taken off..



Is this the correct position for the NVA's spray-hole?



My grandfather's ".35" is in similar condition.. great compression.. (same exact NVA spray-hole position).. and looks to have never been taken apart.

What would be a good glow-plug to run in these engines? There's a hobby shop in Sturbridge, MA where I'm told that I can get fuel with the correct oil-content. The shop caters somewhat to the OTS flyers.. or so I'm told. I'm leaning toward 10-29 "Power-master". Maybe that's a little too much oil.. but where I'm not real experienced with these engines; it's probably better than running fuel with less oil. Most of my (non-Cox) larger-displacement engines are old 50's/60's-vintage relics.. designed for general sport-flying. I'm wondering if I should also buy some alternate fuel for my Fox .15 and Enya .19?

Here's a few pics of those engines..




Thanks a "TON" for any help here.

Roddie, your Fox's don't need 29% oil to work. Powermaster no longer offers 29% oil all castor fuel. They stopped making it a year ago. If you desire this much oil, Brodak offers 5-10% nitro in all castor 29% oil   in qt sizes. The plug in the engine currently appears to be a Fireball. They work fine. A K&B 1L, Mccoy MC-59, OS A3 . Your Fox plugs will run them on the bench just fine I just wouldn't fly with them. None of the engines with the possibility of the .15 you have depicted uses a short plug. They all use longs.

      As for the head of the Fox. The raised casting indicating 29 or 35 on those cases are known as the wide bypass cases. These were produced in the 50's.  Don't make a habit of taking the head off of any of them. The cases can easily be distorted if not properly installed and the case is typically not flat to begin with. Remember these were made with hatchets and not high end machinery.  Not all Fox .35's run the same. This one even though is a .29 suffers from the same fate in that the wide portion of the case opposing the exhaust side is very wide. This tends to load with fuel on the outside maneuvers  drowning out the plug. This inherently is known as the Fox burp. Some Fox's burp worse than others and some don't burp at all. When a Fox is mounted in a sidewinder position ( Profile plane) it burps. When mounted upright, a Fox WON"T burp and it makes more power than mounted sideways. It also offers little to no break when the nose is pointed upwards in the upright position.

          Your spraybar orientation is incorrect. That's the earlier single hole spraybar and the hole shouldn't be visible . It should point down and approximately the same angle as the venturi stack itself. Some suggest to favor the rear of the venturi. While the spaded needle you show is a Fox .35 needle valve, it's not the correct needle for that spraybar. The earlier brass single hole spraybars had their own style needle and taper. If it works, great but the needle you is designed for the two hole spraybar.

          The steelfin .15 needs all castor fuel and the more the better. Use the same fuel for the .29 and .35 and Mccoy's.  The wrist pins are notorious for galling the cylinder and the high oil content will insure protection. The steelfin cylinders are quite soft and non tolerant of lean runs. I would check plug length on the steelfin. It may use a short.

    The Enya as I mentioned above could possibly have issues if too much oil is used. The prop shaft is also different than the Fox steelfin. While these two engines can use similar prop sizes, the Fox has a very small diameter shaft vs the Enya. The Enya being metric is somewhat of a pain in the rear and a metric reamer is in order. For instance a standard MA prop will fit directly onto the Fox but not onto the Enya without opening it up.

Thank You Ken, I save all of your notes in applicable folders.. and will refer to them when working with these engines. My plan is to obtain some good-quality fuel. I'll make some inquiries with the NEST-club fellas.. on where to source fuel locally if possible. Thanks also for the glow-plug recommendations. I don't really know how to tell one from the other. I'll check the plug-length on my Fox steel-fin .15... to see if there's a short-plug installed. I have two of them.. and a Jr. Ringmaster waiting for one. That will likely be a transition-model from 1/2A for me.

One of the engines I scored, is a Cox Tee Dee .09.... and assuming that the glow-head is still ok; it's one of the few in the box that might run with a bit of external-cleaning.. and not too much fussing.

Can anybody spot any potential issues from these photos? It came mounted with an old nylon 8 x 4 prop that I would NOT use.. because of the warnings I've read about. I have 8 x 4 woodies.. if that's a good size for this engine.







I'll obviously clean the crud from the cooling-fins. I don't have an .09 wrench.. or any spare glow-heads yet. I'll probably want to source a wrench.. and at least a couple of glow-heads/gaskets and/or a head-adapter/gaskets for standard 1/4-32 threaded plugs.. for when the original glow-heads become more scarce than they already are. This engine seemed to have decent compression "dry".. and a few drops of "3-in-one" oil placed on the piston through the exhaust-ports proved to increase compression further. I'm pretty excited about running this engine actually. "Ian" sent me Tee Dee's .049/.051 (one of each) for my birthday two years ago.. but I haven't run either yet. Those engines are "like-new" condition. I'd rather run this old .09 before running the smaller engines.

I'll need to search for a C/L model for the Tee Dee .09.. or maybe design my own. The engine-bearers on my Jr. Ringmaster and Jr. Flite-Streak are too wide.. but I think that the Tee Dee would fly either pretty well as a starter-engine. This engine will fill an "in-between" space that I haven't really had engines for. I do have a McCoy .098.. that I've never run.



Even if the McCoy engine ran well.. it's incomparable to a Cox Tee Dee .09.. even if the Cox is sub-par. We'll see...

7x3.5 is the prop to use.

I am pretty sure that I have a couple spare .09 wrenches. Engine bearer width is easily corrected and your .09 would work fine in either airframe.

That engine will clean up nicely. It looks brand new under all that filth.

Ron

Nice find, Roddie. found this article on it:

sceptreflight.com Model Engine Tests / Cox Tee Dee 09

Peter Chinn lists RPM's of a half dozen props he used on it. HP peaked out a touch under 20,000 RPM on 30% nitro. Top Flite 6x4 wood put it over 20,000 RPM, so in flight would take it beyond max HP, so its out. TF 7x3 wood put it at 18,000 RPM, which seems to be right sized. 13,000 RPM on a Power Prop 8x4. Said that loading it below 10,000 - 11,000 RPM was basically lugging it (RPM corresponding to 8x6).

My gut level feeling is 7x3 (depending on make) to 7x6 and may be 8x3, probably 7x4 overall. What I find interesting is here we have a 1962 engine that has similar power output of a 1983 modern sport Schneurle OS Max 10-FSR engine that came out 21 years later. Porting may not be considered Schneurle but apparently is close to it.

Been told that I'd be better off with an .09 - .10 sport Schneurle in my 30", 200 sq. In. Ringmaster Jr. Seems to me the Tee Dee .09 would work really well in that airframe also.

Yeah, and from what I've heard, nylon props don't get better with age and so that T/F 8x4 nylon ought to be retired, something about micro cracks and aging. When new they were great, and could be re-hydrated when stored by boiling, but that prop is beyond boiling.

The McCoy "09" (.098) is the correct engine for Hal DeBolt's 26" All American.

http://outerzone.co.uk/plan_details.asp?ID=347

The .09 doesn't seem to share the popularity of the smaller mills. The .09 glow head for the TD shares the same knurling on the high comp head as the smaller .049's. Yours doesn't seem to be displaying this trademark and could possibly be a Medallion .09 head. Glow heads for these are a bit tougher to locate and can be quite pricy. Yours is the thin walled cylinder indicating it's a early version and with that being said, I would bet the plastic carb body is cracked. Remove the venturi and inspect carefully internally for cracks running perpendicular to the threads. These can be difficult to spot initially due to the cracks closing up when the venturi is removed. More than likely due to the age, it's cracked or expanded outwards. This is very critical to the run of the engine. Depending on how much time is on the engine, the phenolic washer behind the drive plate can be torn up and may require replacing.

The Jr Ringmaster would be a nice choice, while it wasn't designed for the newer TD .09, it's weight and output makes it a good choice. I can't tell you how many times I see builders placing a modern .15 on a Jr Ring. This makes it fly like a turd due to over wing loading and poor maneuverability. The JR was designed around early engines such as the OK .149 which was a light .15 not offering much in power compared to even say a early Fox steelfin. The steelfin was offered in and around the same time the Jr Ringmaster was introduced around 1958.

Ken Cook wrote:The Jr Ringmaster would be a nice choice, while it wasn't designed for the newer TD .09, it's weight and output makes it a good choice. I can't tell you how many times I see builders placing a modern .15 on a Jr Ring. This makes it fly like a turd due to over wing loading and poor maneuverability. The JR was designed around early engines such as the OK .149 which was a light .15 not offering much in power compared to even say a early Fox steelfin. The steelfin was offered in and around the same time the Jr Ringmaster was introduced around 1958.

Re the Ringmaster Jr. with modern .15's, that is an understatement. My OS Max .15FP-S weighs 5 oz without the muffler and is very nose heavy and an overkill in power.
(With muffler, it would climb and dive like the old Scientific half-A's, ) After checking sceptreflight.com, it puts out HP similar to the older cross scavenge .25's, like the Fox.

Was it kitted in 1958? I was under the impression that it was shortly after the S-1 as kit S-5 (early 1950's) by the same master Matt Kania. Jeff Coons had a Sterling Model Collectors blog on mindspring.com (Earthlink) with extensive historical info, but alas, his site is no longer around.

Hey man , Nice haul there somehow i missed you had picked them up from the road sell , i got a TD.09 i need to find a glow for or use the Medallion ones i have ? That .098 McCoy is a good easy running engine (well the one i have is ) lol Looks like your getting ready for some good FUN !! And i wish you the best of success .

Roddie,

I am a current user of the TD09, an excellent runner, and offer you a few ideas:

1. After I got the 1st of my TD09 engines,  I started out with buying a conversion head from Mecoa for glow plug use because I thought genuine 09 heads are on a short supply on ebay. They are, but even today there are a few for sale there, and the output with the genuine head is a tad better than with the conversion head/plug...but the difference is not too high.
2. Also bought from Matt an aluminum carb body (fredvon also sent me one free that I cannot appreciate enough), that fits and works excellent.
3. Matt sold me a R/C carb too, that I use, with satisfaction. Good stable idle (especially with a hot plug in the conversion head),  and the bleed and idle screws are much better fit in their holes than on the 05 where I often lost them.
4. I run the 09 either on a 7x4 2 bladed prop or on a 6x4 3 bladed prop of Master Airrscrew. Both are fine, the 3-bladed is a bit more classy on my Cosmic Wind.
5. I have a 09 muffler  added for noise control, the output is a bit compromised (SPI design), the engine is a bit less noisy, but the castor leaks through all borderlines between the mating  components. So no matter I have the silicone tube extension, the engine cowl collects quite an amount of castor there.
6. with the above setup the engine roars for about  8-9 minutes on 2 oz fuel (60/20/20), and is a real beast...I also compared the engine output curve with those of contemporary and even later 09 engne designs and found it exceptionally strong.http://www.sceptreflight.com/Model%20Engine%20Tests/Cox%20Tee%20Dee%2009.html


7. I have altogether three TD09-s, the one I bought pre-owned/used is currently in the Cosmic Wind, and 2 others are new, waiting for their turns. Interesting to note that out of the 3 engines I have 2x2 booster flutes on only one of them, which may have been added by the previous owner. I will tach this engine and compare to the stock design..the booster flutes may have a similar power booster impact like between the No 1 and No 4 cylinders in the 049 class..

8. Although all 3 of them have stepped wall cylinders (a bit younger design than your thin-wall), all have tapered bore and a nice pinch at the TDC.

Nice finds Roddie

A Queen Bee head would also fit the .09, not sure how it would perform but at least the thread is the same.

Wow guys.. I'm overwhelmed by the comments on my newfound Cox Tee Dee .09. Apparently I have an earlier engine.. which suits me just fine! I don't know much about the carb-bodies. Tee Dee's are new to me. Tee Dee glow-heads are no exception. I figured that there was a Tee Dee head on the engine.. but apparently it may be a Medallion head. I'll try running-her with a wooden spec-prop.. and see what she gives for #'s on the tach.  

Ron, let me know if you have a wrench that you'd be willing to part with. Thanks. My Jr. Ringmaster is RTF for all intents and purposes. This engine with a mount-conversion, might be the ticket to some fun-flying. I'll have to check my aluminum plate-stock.. and see if I can make something work.

I have a week-off, coming-up prior to Memorial Day. I hope to do some flying that week. I've got plenty of C/L airframes ready for engines.. Between now and then; I need to get some engines ready... and some lines made-up.

I should have 2 extra, and you need 2 so hit me up in a week, I am travelling at the moment.