Olympic. 15 throttle ring or sleeve...

getback wrote:May have to watch eBay , A slide throttle would bee better if you could fit one in there , more expensive though and still harder to get ,But need to make sure it will fit , Never seen in production a Olympic .15 throttle ?

Yes, sir,I am. Thank you. I have three separate searches, worded differently with notifications checked. I may sell some of my other stuff to purchase the Olympic with the air choke/throttle wannabe block thing sticking waaaay out the back of it. I am afraid that it would lag worse than an under powered Turbo. But, it sure looks neato. Almost like a velocity stack or a single high-rise intake on a side draft carburetor! I wonder if it has any (even tiny,infinitesimally small) effect on torque?! Not a measurable amount, anyway. Next wild idea: Anyone ever see a diesel head on a Cox .15 of any flavor?

CT

I already put a carburetor to use as a simple valve on my sportsman and it didn't really affect its performance and gave me good results. I simply added a tube and OS .15 carburetor that did it. The only one ting I didn't like is having to break through the fire wall Something rare But I like this silencer, an rc silencer used like the rc restrictive ring but with an integrated silencer not to be confused with a simple silencer It works very well
A medallion with this rc silencer is a very good choice for light engine, much less noisy than the original

Thank you! There is a slide muffler/throttle on evilBay, now. It's stuck and the bracket for the needle valve looks mutilated. It comes with a Medallion that looks nice, but, I really don't need it... I put in two offers... no joy. I may have a carburetor that I could adapt to the Olympic. I was reading the specs page and it does not differentiate on the cylinder threads. I am sure I could free up the slide throttle, but dang, all the shipping and fees to evilBay, even if I turn around and flip the Medallion...

C.T.

davidll1984 wrote:I already put a carburetor to use as a simple valve on my sportsman and it didn't really affect its performance and gave me good results. I simply added a tube and OS .15 carburetor that did it. The only one ting  I didn't like is having to break through the fire wall    Something rare But I like this silencer,   an rc silencer used like the rc restrictive ring but with an integrated silencer not to be confused with a simple silencer It works very well
A medallion with this rc silencer is a very good choice for light engine, much less noisy than the original

How is the servo hooked to one of those spring steel tips sticking out? Man, what a great foru.! Thank all y'all for your patience an sharing of knowledge! The efforts to find references and measure things has been phenomenal!
I, too am leary of the breach in the firewall. I plan on putting a secondary bulkhead/ firewall aft of it, after I figure out the airducting to get that monster fed!

CT

C.T.

Boats13 wrote:How is the servo hooked to one of those spring steel  tips sticking out?

The spring steel is a sliding window covering the muffler's exterior slot, to manually control the amount of muffling, less muffling with more exposed slot, more power, more muffling with covering the slot, increased power loss.

The servo is connected to the holes in the end of the C-Clip underneath the muffling chamber, ends exposed to the rear nearer the needle valve in the photo. One can manually align those holes for proper servo engagement by sliding the C-Clip ends to desired orientation.

Well, I feel stupid. I've used a regular sleeve for years (on my .09), but I thought those style somehow used that ratcheting spring steel to actually throttle it. So, the whole thing moves?! Cool, so its a lighter aluminum sleeve and adjusts the sound level, that's so cool. I am learning just how much I have no clue about!
C.T.

Exactly you understand but be careful. know that two models of silencer exist, one does not have the rc function and does not turn once installed, both are the same Or almost from the outside here is the way to distinguish it is the snap ring at the bottom

David,
Thanks, I've never seen an aluminum one with the snap ring. That's why I thought it had to be hooked to the spring, somehow...

Well, I am off to heat gun a brand new Medallion that is stuck.

C.T.

I've got the Sportsman .15 muffling unit, @Mike1484 graciously and gratuitously sent me that and other parts for my .15 Sportsman.

https://www.coxengineforum.com/t17159-just-won-a-cox-15-sportsman#223115


If you will notice, the non-throttle muffle only unit is hollow inside with no sleeve over the cylinder exhaust. One can orient the exhaust outlet, but once cylinder is on, it is held in place by the friction of the fit, doesn't naturally rotate like David's rotating exhaust throttle muffling unit.

The nice thing about this muffling unit is it is light weight, which should do well on a C/L aircraft, especially since the Sportsman doesn't use SPI. Thus, there is no exhaust gas recirculating into the crankcase to dillute the fuel charge and reduce power.

Unmuffled, I can imagine that this larger Sportsman will be loud. I've heard the same comments about the OK Cub .14 and the Testor .19 Red Head.

Another thing to know is that several cylinders exist for the .15 but not all are the same take the sportsman for example has a smaller cylinder than the medallion larger also the medallion has a different cylinder and  piston dimension. the one that I have with the cylinder wit rc restrictor ring does not fit in the rc silencer I believe that the cylinder which must be used with it is machined smaller Which makes it more complicated and harder to find the parts to modify The .15 engine . One Good thing wit .049 rc cylinders have the same external diameter and can be used both the ring or the rc silencer And yes the .15 is really a noisy engine, you can hear it from afar And even confused with a real plane I already saw a guy arrive in panic he thought that a plane in difficulty had just landed in the field but no... it was me

Where noise isn't a problem and particularly with the Medallions, the unmuffled throttle ring is preferable, because this mode produce's the most power for the Medallions, because the earlier editions have SPI. The throttle ring still allows SPI to function. This is the ring above in @davidll1984 's photo.

I have one example of a muffle-throttle Medallion .09, Cox still sold these even though exhaust gas recirculation by SPI dilluted the fuel charge, reducing power. Philosophy was still for a reasonable price, it made a nice throttled engine. I guess Cox still had the sales, why they continued selling them into the Estes era.

For my Sportsman, I will use unthrottled, was aspiring to relive the days of the early 1960's Cox Piper Comanche with such an engine. Another friend in this forum, @MauricioB from Argentina posted a video 3 years ago of him flying his R/C sport plane powered by the Sportsman with a custom muffler he skillfully machined for it:

https://www.coxengineforum.com/t17159-just-won-a-cox-15-sportsman#221970


Here is a video Mauricio found and posted of the venerable Cox Piper Comanche in flight. It is the largest C/L RTF Cox ever made. I guess they did not have the sales, so it was discontinued after a few years. From photos and catalog cutsheet, it was a real beauty for beholding.

https://www.coxengineforum.com/t17159-just-won-a-cox-15-sportsman#222051


Mauricio's custom made muffler does not have any sliding spring steel window on it, which shows that it is not necessary. The muffler @Mike1484 (thanks Mike!) gave me is missing the spring steel slider, but I can manufacture one out of spring brass or drill two small holes and mount a fixed roof flash sheet steel cover over it.

My ultimate goal when I am settled home-wise is to incorporate the engine into a C/L plane, to relive the days of the Comanche. Best candidate I have is my Midwest 33-in. (838 mm) wingspan Midwest Curtiss P-40 Warhawk profile kit, a shoe-in for it.

https://www.coxengineforum.com/t6340-p-40-kittyhawk-stunter#86711

Awesome plan! I have an Earl Stahl P-40 that will be (cough, cough) electric R/C. The .15 Olympic will be put in my Peck's Prairie Bird 50. I really will have to throttle it. Somehow! Must be patient. Thanks for the continued help and info...
Mention the Comanche, and they will come:

https://www.ebay.com/itm/364783891152

David, thank you, also.

I have to stop binge reading this forum on my phone and finish my dang computer! I can't program my transmitter and several receivers without it. I have a new rf module that I need to edit the protocols and the order they're in.

CT

Boats13 wrote:The .15 Olympic will be put in my Peck's Prairie Bird 50. I really will have to throttle it. Somehow!  Must be patient.  Thanks for the continued help and info... Mention the Comanche,  and they will come:

https://www.ebay.com/itm/364783891152

Nice, well preserved Comanche and from a reliable seller, curmatt_1. I have bought several items from him to include engines. Love the detail that Cox put into this model, to make it an accurate rendition of the Piper Comanche. Just a little pricey for me.  

Boats13 wrote:I have to stop binge reading this forum on my phone and finish my dang computer! I can't program my transmitter and several receivers without it. I have a new rf module that I need to edit the protocols and the order they're in.

Posted it here: https://www.coxengineforum.com/t17065p50-s-m-a-l-l-2023-here-we-go#224331

Last Spring I gutted an old ATX tower case and cleaned it up, installed a blazingly fast Intel i7 motherboard system with 3.8 GHz quad processor each with dual cores, 16 GB RAM and a half Gig solid state hard disk, new DVD recorder, multi card reader unit and USB expansion card for 8 USB ports additional to compliment the 4 that came with the mobo.

Using Ubuntu Mate Linux:

Here's a short 14 minute Cox production video from the early 1960's, featuring the .15 Sportsman powered Comanche RTF as well as their other planes.



Desafortunadamente, recibí un mensaje,
«Vídeo no disponible. El propietario del vídeo inhabilitó la reproducción en otros sitios web. Mirar en YouTube».
Unfortunately, I received a message,
"Video not available. The video owner prevents reproduction on other web sites. Watch on YouTube."

¡Desfrute!
Enjoy!

What a cool piece of History! Thanks for sharing... amazing difference to today's short flashes and chopped up production.

CT