Which Cox 15 have I got?

[Andrew Tinsley]

Hello Guys,
A friend of mine gave me what he thought was a Cox Tee Dee 0.049 engine. When it arrived it was, in fact larger than a TD 0.09! So it must be either a Cox 0.15 T D or a Cox 0.15 Mk1 or Mk2. So how do you tell the difference? This engine has a black plastic carb mount with a gold anodized ring (with spanner flats) and a plain aluminium carb. It also has a gold anodised prop driver. The main aluminium crank case is not anodised The only other odd thing is that it has one exhaust port. It is frozen solid, so I have no idea about the transfer ports. 
  I presume that it would be good for a traditional Brit high speed stunter that was designed for hot diesels. The sort of stunter we had back in the 1950s and early 1960s?. It looks as though it would clean up pretty well and doesn't seem to have had much use. I am a bit of a small Cox enthusiast, but my knowledge and experience runs out at anything above a 0.09 capacity.
  It has a good glowhead, but I assume that they could be difficult and expensive to source, so a Nelson head conversion looks like the way to go. Any comments or information would be gratefully received.

Thanks,

Andrew. 

[John Stiles]

More than likely a TD.   http://www.ebay.com/itm/Cox-TD-15-Glowplug-Model-Aero-Engine-/290885443946?pt=US_Radio_Control_Control_Line&hash=item43ba1fa16a

[Dan Berry]

Single exhaust port makes it a Special Mk11. I think.
It probably has three sorta schnuerle intake ports.

[Andrew Tinsley]

Thanks Dan,
I have never come across a TD 0.15, let alone the Mk1 or Mk2 Special. They may be common in the US, but over the this side of the pond, they sure are a rarity! Should I put it on display as a rare engine or just go ahead and use it (provided it is in reasonable mechanical nick)? I will strip it down and give the internals a good clean. Does it have a wrist pin or just a big ball joint a la smaller Cox's? Although I will soon find out!

Thanks again,

Andrew.

[Dan Berry]

Shewt, I don't know if you should use it. It ain't a tame engine. There are no mufflers for it.

[Jim Scott]

Go here for more information on Cox engines:

http://www.mh-aerotools.de/airfoils/cox_frameset.htm

Excellent source and detailed information on all the versions.

Jim

[John Stiles]

Sorry I missed the part about "single port"...the one I posted was a Mk1: Cox TD  Special 15  Mk I (2.5cc) glow plug motor along with a factory muffler (not fitted) and a Cox cylinder head that allows the fitting of generic glow plug cores. These beautifully engineered, lightweight, motors were very advanced when they were first produced in the early 1960s. They were competition-orientated and the TD 15 would put out 0.4 bhp at an astonishing 18,000 rpm. They were very well suited for free flight and indeed an earlier iteration of this motor won the World Championships in 1960 but were also successful in control line events, particularly combat.

This particular engine is identified as a Mk 1 by its twin exhaust ports.

[john e. holliday]

In 64 at the NATS the Meriwether's were flying A speed.   Their engine came apart and Mr. Meriwether went to get parts.  Dale Kirn handed him an engine and stated it was one of the prototypes being developed.  It had single exhaust and fit right in where the old broken Tee Dee used to sit.   Wayne did well enough with it to get the Junior National Trophy that year.   When Mr. Meriwether passed on I got all of the control line stuff to keep it out of the dump.   When I found the engine I sent it to Dale Kirn and got a nice note thanking me and he vaguely remembered the incident.   1964 was my first NATS and I will never forget it.   

How about a pic of your engine.

[Larry Renger]

the Mk II was not that good an engine and Cox went bback to the dual bypass, dual exhaust for the rest of the production runs of the TD.15. this engine would be very "iffy" in a stunter and likely need pressure fuel feed. i would mount it on a stand for diplay.

[Bill Morell]

Might not be that good of a engine but they sure bring big bucks on ebay. Last one that was NIB went for over $300. Why not clean it up and sell it on there and get something that you could use?

[Andrew Tinsley]

Thanks Guys
 I will post a picture if I can. Sounds like a Mk2 Special. If it is worth significant money, I will strip it down, give it a good clean and send it back to my friend. He can decide what to do with it! I can fly without mufflers (remote location) and the stunters of my youth used to fly at around 75mph plus, so I may just be tempted. I still have a Black ghost or two!

Andrew.

[Paul Smith]

When they first hit the market TeeDee 15's were a huge jump in performance and reliablity vs. the generally poor 15's of the day.  Because of the disappointing performance of 15's, most people jumped right from .049's to the 29/35 size.  As result there weren't many 15-size planes to chose from.

One of my neighbors got a TeeDee 15 and put it on a Goldberg Spaceman 30.  A plane that small with a sheet balsa wing really moves with hot 15.

Not such a hot tip for combat when the plastic front end checks the turf.

[Jim Thomerson]

Here is my Darter, a scaled down Agile Arrow, set up as a profile with Cox MK I 15.  It flew the pattern very well, but at its first contest in Dallas, in practice, it blew a rod.  I tried some different engines and did not get it to suit, so it sits in the rack in need of minor repair.

[dale gleason]

Awesome! Jim,and Kewl as they say nowdays. And Rad, forgot Rad...
dg

[Garf]

Be careful on disassembly. If the piston is frozen in the cylinder and it has a wrist pin, when you attempt to unscrew the cylinder, it will wring off the rod.

[Andrew Tinsley]

Thanks for that timely reminder Garf.

Regards,

Andrew.

[Brian Hampton]

Hi Andrew
I've got a similar 15 to yours (single exhaust, wrist pin for conrod) which at first indicates a Special 15 Mk II but the crankcase on mine isn't anodised gold either as it should be on the MK II. Also the threads the cylinder screws into don't allow the exhaust to face directly to the LH side. My guess is that it's either an earlier crankcase with the Special MK II piston/cylinder/rod fitted or it started as a Mk II and someone broke the original crankcase.

BTW, that cheque hasn't been cashed yet......

[Jim Thomerson]

I tried screwing an MKII liner into a silver crankcase with the same result.

[Andrew Tinsley]

Hello Brian and Jim,
My Mk2(?) doesn't have an anodised body and the single exhaust is not facing the side either (maybe an extra 30 degrees). Odd that two engines are the same, maybe Cox ran out of anodised bodies, or they are both rebuilds using a standard TD case. Who knows!
  I shall send daughter a text re the cheque! I think she has probably forgot all about it, because after a VERY long time she is expecting a baby! If I say it is for baby cloths, then it will probably be cashed straight away! I will keep you posted, if she doesn't cash it soon, she will lose it!!

Best Regards,

Andrew.

P.S. Don't mind if it is a boy or girl, whatever, there will be a Tomboy built for the new arrival!

[Jim Thomerson]

I understand that threads in the Cox crankcases have a random starting position.  This is why Cox cylinders orient in different positions on different cases.  I presume this was not the case with the MKII crankcase as the cylinder needed a fixed orientation. 

[Larry Renger]

Yup!o