Cox Medallion .049 r/c 1968

Nice performance, it works well on the .09 engine too.

Thanks guys for your comments. It is important to note that this accessory is not possible to be placed in any cylinder of Cox Medallion, it can only be placed in thin-walled cylinders, I clarify this because I thought it was something very simple, however I had to adapt the silencer, beyond that I am using a cylinder of two transfer tubes and thin walls with skirt.

Mauricio, great video!  I too am a lover of those Cox throttles.  I do not know why they were not more popular.  I understand that the rotating throttle ring was much smaller and more compact, simpler, and cheaper to make.  But none of the throttle rings regulated RPM as well as these throttles do.  While I have only run the .049 Medallion with this throttle so far, I have the Medallions in .09 and .15 with these throttles.  I love the response on my Medallion .049 with these.  I found the response pretty much the same as on your video.  Having pretty much stuck with Control Line since I got back into modelling, I haven't had a need for the throttled engines.  But someday, maybe.  

Hmmm... Now that I think about it, I have been stuck on my ME-109Z as far as how I'm going to do my engines.  Maybe two throttled Medallions on it and I can fly it in 1/2A Semi-Scale Profile contests.

Thanks again for the video,
The "Not A Fighter" Mark

Agree, Mauricio, that's a nice demonstration of the earlier Cox Medallion throttle assembly. I hadn't realized you could get a really low reliable idle. Plus, response seems more linear over the exhaust throttle ring.

I've used the more modern muffled and unmuffled throttle rings on the reedies, R/C Bee (muffled) and Golden Bee (unmuffled). They worked well and were reasonably inexpensive, but never got that tick over idle.

I gather that though a better product, that it was more expensive to manufacture and back then there was less demand for throttle. Cox needed to be competitively priced with the other RC half-A engines out there. Would understand why the assembly would not fit the later thicker walled cylinders, item was discontinued before them.

You've illustrated a nice piece of past history we see little of now.

batjac wrote:Mauricio, great video!  I too am a lover of those Cox throttles.  I do not know why they were not more popular.  I understand that the rotating throttle ring was much smaller and more compact, simpler, and cheaper to make.  But none of the throttle rings regulated RPM as well as these throttles do.  While I have only run the .049 Medallion with this throttle so far, I have the Medallions in .09 and .15 with these throttles.  I love the response on my Medallion .049 with these.  I found the response pretty much the same as on your video.  Having pretty much stuck with Control Line since I got back into modelling, I haven't had a need for the throttled engines.  But someday, maybe.  

Hmmm... Now that I think about it, I have been stuck on my ME-109Z as far as how I'm going to do my engines.  Maybe two throttled Medallions on it and I can fly it in 1/2A Semi-Scale Profile contests.

Thanks again for the video,
The "Not A Fighter" Mark

Friend, thank you very much for your comment!
It is the first time that I use this motor configuration, that is to say the Medallion with accelerator type "bar". It's a wonder, even as it interacts with the venturi spray bar, sindudas is a masterpiece.
I understand that you are a more expensive piece to manufacture, it even takes more parts and maybe even more bulky when trying to place in a model, than the simple strangler ring, but this piece, with its shape, its details, the relief that says COX, and their way of working, they are a piece that can not be forgotten.
It is right that these types of accelerators come to light, it is fair and worthy to show them, because they are a work of art. I can not explain what it feels like to personally enjoy the progress of one of these engines. You friend, you must undoubtedly give rise to that project and do something that uses the Medallion with Carburetor "bar" ... it would be an honor to see something like that.
Personally I have proposed to make some appropriate model for this engine ... and I will put hands to the wood ... this is worth enjoying !!! ....

MauricioB wrote:Personally I have proposed to make some appropriate model for this engine ... and I will put hands to the wood ... this is worth enjoying !!! ....

Actually, if you want something classic and easy to build, it's hard to beat the Q-Tee.  That would be an excellent build for this motor.  In fact, I have repeatedly thought about backfitting my Q-Tee to use this, if I ever get back to RC.

Q-Tee plans and article:  https://outerzone.co.uk/plan_details.asp?ID=1350




Ignore the pics of the heretics using electric for their Q-Tee.  I'll try and post a pic of my Q-Tee tomorrow.

The Classic (i.e.Old) Mark

GallopingGhostler wrote:Agree, Mauricio, that's a nice demonstration of the earlier Cox Medallion throttle assembly. I hadn't realized you could get a really low reliable idle. Plus, response seems more linear over the exhaust throttle ring.

I've used the more modern muffled and unmuffled throttle rings on the reedies, R/C Bee (muffled) and Golden Bee (unmuffled). They worked well and were reasonably inexpensive, but never got that tick over idle.

I gather that though a better product, that it was more expensive to manufacture and back then there was less demand for throttle. Cox needed to be competitively priced with the other RC half-A engines out there. Would understand why the assembly would not fit the later thicker walled cylinders, item was discontinued before them.

You've illustrated a nice piece of past history we see little of now.

Thank you Friend for allowing me to reflote part of the history of a product of your land.
I admire these jewels and "I take my hat off" before so much talent shown here in these pieces.
A few days ago I spoke with a friend from my country and I said, "If someone criticized the Cox engines, it was because of ignorance, it was because they did not have the necessary elements to learn how to use them"
From here I give the necessary support, to fervently value each product of Cox, because in truth they are a mechanical marvel. Admiration ... a poor word that is not enough to describe everything a Cox represents.
I thank you and I thank you all for freely allowing me to express myself, value and demonstrate that Cox is equal to Quality! ... of the best.

Here I try to make an Illustration of avoiding conflicts with the application of this type of accelerator "bar"

Green: OK
Red: It is not possible to use.

batjac wrote:

MauricioB wrote:Personally I have proposed to make some appropriate model for this engine ... and I will put hands to the wood ... this is worth enjoying !!! ....

Actually, if you want something classic and easy to build, it's hard to beat the Q-Tee.  That would be an excellent build for this motor.  In fact, I have repeatedly thought about backfitting my Q-Tee to use this, if I ever get back to RC.

Q-Tee plans and article:  https://outerzone.co.uk/plan_details.asp?ID=1350




Ignore the pics of the heretics using electric for their Q-Tee.  I'll try and post a pic of my Q-Tee tomorrow.

The Classic (i.e.Old) Mark

thanks again friend ... mmmm .... I have something in mind, I have something in mind, it's just time for the painter who paints my house to finish and use my workshop!

Electric? ... no! .... for some reason the nature to God thanks to many gave us ears and touch and smell and ... and ..... the electric kills all the above ... There is no sound of the rpm , there is no touch to fuel and oil and there is no smell of burnt fuel ... maybe it is not very healthy, but ... it is worth to enjoy all the senses, it really is worth it!

Surfer_kris wrote:Nice performance, it works well on the .09 engine too.

Kris ... please, put your engines in gear and have a video, share it here ... can you do it? ... I know that it is!

Anyone who has a similar engine, please share a video, it's a Cox piece, worthy of sharing and admiring .... hey Kim! ... your .15 must be here too!

Thanks for info.

Throttle ring works with SPI cylinders but need to seal well. A little grease inside of throttle ring helps.

Congratulations Mauricio!!!

Engine idle runs very smooooth!!!!

Levent Suberk wrote:Throttle ring works with SPI cylinders but need to seal well. A little grease inside of throttle ring helps.

Back in the 1970's, I remember the Ace R/C catalog had 2 different models of their throttle ring. It depended on the style of the cylinder used, one cylinder had a slightly larger diameter than the other. I got the correct one for my Golden Bee and it worked fine with SPI.

Yes, Q-Tee is a good model for any Cox engine

https://www.worthpoint.com/worthopedia/tee-rc-kit-cox-airtronics-2a-sport-1721305997

My friend Mauricio , That was great ! i have not seen or heard one of these run and that was a very good execution of what it will do at idle and to full throttle . I have had a few of the ,049s and .15 ones and just got another off Ebay was described as a .049 but when i got it was a .09 That makes it complete collect but they all need a part made or a little work to get up and running .049 .09 .15 The transition sounds nice do you think better that the Carburetor ?

I've never seen one of those throttles before. I have a couple thin wall Medallions waiting in the queue. One more thing to add to my list of "must haves".

Is the part on the venturi an active part of the throttle, a butterfly or something or is it just a bushing to keep the barrel stabilized?

Thanks for sharing!

Speaking of the Q-Tee, I installed a Norvel .061 Big Mig C/L version and made it a really nice sport plane with good wind penetration and manoeuvrability.
That moved it out of the trainer class into the sport fun class.

Interestingly enough, my 36" (915mm) span 1974 DeBolt Livewire Champ Jr. (stand off scale Aeronca Champion - smaller model of the larger Livewire Champ) plans show a Medallion .049 engine installed (although a reedie work work also) installed. This earlier Medallion .049 R/C or even a later one would be a natural shoe in.

Dave P. wrote:I've never seen one of those throttles before.  I have a couple thin wall Medallions waiting in the queue.  One more thing to add to my list of "must haves".

Is the part on the venturi an active part of the throttle, a butterfly or something or is it just a bushing to keep the barrel stabilized?

Thanks for sharing!

Friend, thank you for leaving your message, I made this video quickly for you. I hope you can appreciate the movement of the spray bar, at the same time that the acceleration bar moves.

Levent Suberk wrote:Thanks for info.

Throttle ring works with SPI cylinders but need to seal well. A little grease inside of throttle ring helps.

You might be better served by using a very small amount of anti-seize compound on the throttle ring.
Most greases tend to melt and get very sticky when heated ( as it would on the hot cylinder) and when cooled can harden.
YMMV, Steve...……...

Dave P. wrote:Is the part on the venturi an active part of the throttle, a butterfly or something or is it just a bushing to keep the barrel stabilized?

Someone here in this forum, I think it may have been Mark Boesen showed a photo of the venturi spray bar when I asked a while back. The round rotating spray bar is machined to be narrower along one axis so that more air passes when at full throttle, but restricts when throttle is closed effectively acting like it was a butterfly. So, it is a functional part of the throttling system.

66 Malibu wrote:

Levent Suberk wrote:Thanks for info.

Throttle ring works with SPI cylinders but need to seal well. A little grease inside of throttle ring helps.

You might be better served by using a very small amount of anti-seize compound on the throttle ring.
Most greases tend to melt and get very sticky when heated ( as it would on the hot cylinder) and when cooled can harden.
YMMV, Steve...……...

Quite right. I use high temperature grease.

Flor de maquinita.