1978 Cox Hobbies Catalogs

YES lets peck inside

Sorry it took so long guys.

I really meant to handle this right after I found them.

I have them scanned as PDFs. The main catalog is almost 16 MB. The supplement is almost 4 MB.

Any help would be appreciated....then you get to look too!

My favorite plane in the set is the New Era...an R/C bird finished in blue and white.
I always loved the blue finish, and as a kid wanted my models to look THAT good!

Yes please, take
“twenty-seven eight-by-ten color glossy photographs with circles
And arrows and a paragraph on the back of each one explaining what each
One was”.  Arlo Guthrie

Or PDF s will do.  

The Cox Dune buggy graduated to the "Duneblaster" by 1977 and later, as seen on the Catalog cover page, Actually, If you look inside the catalog you will see a Yellow duneblaster in the box. I painted a Duneblaster Yellow with Base Coat Clearcoat paint. Also, as the company winded down Cox deleted the chrome plating on its models, changed the needle valves to the mickey Mouse aluminum needle valves and the Nylon Backplates. I use only Delrin Backplates wich hold up to much more heat and higher Nitro. Glen Bolton did a great Job with the Design of the Heat sink, Snap start engine and other ideas.

Jacob posted them in the members-only section  for instructions.

Thanks to Jacob!

Bill steklenski wrote:  Also, as the company winded down Cox deleted the chrome plating on its models, changed the needle valves to the mickey Mouse aluminum needle valves and the Nylon Backplates. I use only Delrin Backplates wich hold up to much more heat and higher Nitro.   

Hi Bill! You raise an interesting point in Cox's plastic (product-engine) backplate-construction. Is there a way to know the difference between a "Delrin" backplate.. and a "Nylon" one? I would assume that the plastic postage-stamp (early)backplates were all Delrin.. but I'm not sure about that. Were any of the "newer-generation" horseshoe backplates molded from Delrin?

Thanks in advance..

roddie wrote:

Bill steklenski wrote:Also, as the company winded down Cox deleted the chrome plating on its models, changed the needle valves to the mickey Mouse aluminum needle valves and the Nylon Backplates. I use only Delrin Backplates wich hold up to much more heat and higher Nitro.

Hi Bill! You raise an interesting point in Cox's plastic (product-engine) backplate-construction. Is there a way to know the difference between a "Delrin" backplate.. and a "Nylon" one? I would assume that the plastic postage-stamp (early)backplates were all Delrin.. but I'm not sure about that. Were any of the "newer-generation" horseshoe backplates molded from Delrin?

This is an interesting discussion, something I never thought about. Without getting too deeply into the matter, did a little searching. Found this interesting explanation from Dupont, makers of Delrin, which is their registered patented product.

Dupont Delrin® Acetal Resin

Dupont wrote:
DuPont™ Delrin® acetal homopolymer resin is a highly-crystalline engineering thermoplastic that industry leaders specify for high load mechanical applications, such as gears, safety restraints, door systems, conveyor belts, healthcare delivery devices and components across a diverse range of products and industries

Delrin® acetal (Polyoxymethylene POM) combines low friction and high wear resistance with the stiffness and strength needed in parts designed to replace metal. It provides a wide operating temperature range (-40°C to 120°C), good colorability and good mating with metal and other polymers, as well as dimensional stability in high precision molding.

Regarding the Sure Starts, since they came out later, there's been improvement in plastics technology since. Low cost and adequate performance are key, don't know what plastic Cox decided on, but probably similar to Delrin and may be cheaper.

My R/C Bee got a lot of use and didn't seem to have much appreciable wear in the reed valve area.

Does anyone have high mileage Sure Starts that they could reveal how much wear and tear has occurred in the reed valve area, along with any changes to the plastic such as distortion or weakening?

Hi George, I have five "horseshoe-style" backplates which were molded in black-plastic. Two of them were from .049 product-engines in two different Cox ARF C/L models from the mid 1980's. One was my Cosmic Wind (1986)  and the other was my PT-19 Flight-Trainer (1987). Both backplates had the "circlip" style reed-retainer.. but were equipped with the newer Mylar/oblong reed.

Interestingly; that PT-19 was a gift from my dad sometime around 1988. The "Cosmic Wind" I would purchase on my own; soon after.. (within a year).. but it was technically an "earlier-production" model, than my PT-19. The "Cosmic-Wind" may have sat on a shelf in the store for a while. I can't remember where I bought it. The Cosmic Wind came with two different propellers; a 5"d. x 2"p. and a 5"d. x 4"p.; both molded in the "softer/flexible" black plastic. I still have both propellers.. in reasonably good condition.



I digress.. I should point-out; that I ordered (direct from Cox) three-more backplate/carbs in 1991.. when I realized that they could be mounted "radially" with four little wood-screws"...... to a balsa-model's firewall. That's when I started designing my own 1/2A C/L models.

See my original Cox orders below..



In 1993.. I ordered "three more" backplates/carbs.. but the price had increased by $1.10/ea. and the design had changed to the "cap-style" reed-retainer; having a flange in the shape of a crankcase-gasket.




I rebuilt a few engines with the new reed-retainer... but would take a LONG (20 year) hiatus, before getting back-into Cox .049 reed-valve engines.

As of "late" (2017).. I have ordered several "Sure-Start" style backplates; which are the "same" horseshoe-configuration.. except with the new "snap-on" cap/retainer.




These "back-end/carb" assemblies were set-up last year on several of my 1/2A C/L models... but unfortunately not flown. Hopefully this year.. it will happen.






Hopefully.. the plastic used on these carbs will "hold-up".. as well as the "Delrin" did. I will be leaving "instructions" for my grandchildren.. on how to run these engines.

Roddie, I kind of wondered about the switch to a separate plastic retainer versus a music wire retainer. Would take someone intimate with the manufacture's design team to know. My guess is that the plastic reed retainer is cheaper to make than the molding / machining of the spring retainer area in the back along with making springs, going to a less expensive plastic, plus the use of plastic styled reed valves, (Teflon, etc.) may be the plastic retainer is kinder to it. Also, may be the change in retainers made it quicker to assemble the engines. Obviously it was a cost cutting measure of some sort. Did it change how the engine operates? I doubt it.

Someone with a high mileage Sure Start engine would know how well the newer backs wear.

Toward the end I thought it kind of odd that OS would replace their LA aluminum engine backs with plastic, along the plastic carbs for the .10 engine. Obviously it was a cost cutting measure. Hate to sound a little silly for it, but as a result I never acquired any OS LA engines.

The black plastic backplates on my engines tend to crack and crumble over time. I found several gray backplates cracked at the spraybar hole. Any one had that same experience? I haven't found any nylon type backplate as I tried dying some white ones and they wouldn't take any color as nylon parts normally would.
Coxaddict

I haven’t had any problems with disintegrating backplates, although I rarely ever use them as the TD and Medallions are superior in every way.

If one was dead set on using plastic/delrin backplate engines it might be wise to just stock up on spare parts.

Ron

coxaddict wrote:The black plastic backplates on my engines tend to crack and crumble over time. I found several gray backplates cracked at the spraybar hole. Any one had that same experience? I haven't found any nylon type backplate as I tried dying some white ones and they wouldn't take any color as nylon parts normally would.
Coxaddict

My .074 Queen Bee R/C engine during storage developed splits in the black plastic carburetor spacer, carb mount area screw holes housing. This spacer contains the reed valve housing and is the mounting area for the black plastic carburetor. A new one from Ex Engines recently fixed the problem.



I gather that they probably should have made this area thicker, but it is possible that the engineer's calculations didn't take into account aging plastic.

I don't know if this is the same black plastic as used for the black horseshoe back, but if it is, may support coxaddict's observation that the plastic is not as sturdy as the Delrin ones.

The best I can tell you guys is that the delrin backplates are a solid cream white color both horseshoe and postage stamp style. Being a Auto body tech and also having my own shop for 10 years I can see colors very well. The nylon white backplate look like a "transparent" white and on the cars melt prematurely from crankcase heat therefore creating a vacuum leak and failing. Look at a Cox jeep or Adam 12 car on eBay very carefully and you will see the difference. Around 2001 I ran one of my jeeps 10 times straight on 35% Cox racing fuel and then sent the backplate to Dan Sitter in California for inspection. He spent 10 or 12 years of his life researching the Cox factory and has written some very interesting publications.

I have had a little luck with the red/ orange backplates, I have a Cox Sandblaster with a grey backplate that works well. Remember, for us car Guys, we need to let the engines cool down between runs. I think Cox changed to the red backplate by1974 or 1975? The grey sure start backplate and the black backplate seem to work very well also.

I am converting my Jeep that is on you tube to electric r/c and also have installed Ran led headlights and tailights. I just picked up the Last Adam 12 car on eBay and am looking to clean it up and run it. Cox Action Power!!!!!!! I promise to get some photos up soon. Got a NOS jeep body kit and 2 Sandblaster body kits coming from the mighty gascarman! We need more toys!!!!

Thanks DuPont for your Input. I have been using Chromabase and Chromapremier basecoat since 1990. All the people out at the Lionville PA facility are wonderfull. I miss the "suffix" X Imron Polyurethane enamel. We used it previously at Augusta Aerospace Corporation, Example, A109 power Helicopters Etrade N825CC, Ernest and Julio Gallo N77EJ, Careflite Med Evac N143CF, Dallas Fort Worth, just to name a few. Check out Careflight on you tube if its still on there, The Stripes on the Rotorcraft remind me of a AAR Cuda, I believe the paintwork was like $33,000, pretty trick for a 4 Million dollar Med Evac.

Well its about time I answered your first question, sorry, I was getting so Excited this Morning about the cox Engines and Cars. I am not sure if any of the Black Backplates are Delrin,

Bill steklenski wrote:I am not sure if any of the Black Backplates are Delrin.

There's a good possibility that it is not, also that it may not be a Dupont plastic. Delrin has been out for a while. There's no problem of substituting another manufacturer's product, particularly if it is equal to or superior to Delrin.
Obiviously, the material was less than a good choice (marketing again).

Over time, I've seen poor designs with the wrong materials. On one construction project back in the 1990's, the contractor installed a well known brand name commercial quality door knob and lock system on a health clinic remodel. I was surprised to see door knobs fail during the 1 year warranty period. Come to find out, an alignment pin was made from a soft plastic. The older ones were made of metal, brass or steel. The plastic sheered over time causing knob lock failure.

My relatively expensive Fitbit HR bracelet bezel and case were made compact by reducing plastic sections around the electronics. Problem is that by doing so made it more fragile. When it broke, I glued it back together with ABS plastic cement, worked for about 6 weeks then broke again.

Model was short lived and now they have another. I bought a Garmin HR one, which is more sturdy to replace it. I see it as marketing placing unreasonable constraints on engineering to produce something that looks sheik and fashionable at the risk of product failure for the sake of raising profitability to stock holders.

Ditto goes for the plastics used in some car interiors, too.

Thanks so much for posting that info, I have met many DuPont Representatives over the Years but it all pertained to the Auto paint chemicals. I did speak with a Collector from California some years back who has over 2000 pages of info from the Cox Factory including interoffice memos, perhaps blueprints and a wealth of info but I am no longer able to get a hold of him for Reference. If one of you guys truly wants to see what I call the Bulletproof Backplates the Cox 191-4 Jeep engine would show the best example. I am claiming that the very Early backplates are Delrin based on what I was told, Also, when I just Googled Delrin Properties the Technical information was different than what I saw before, I thought Delrin did not start to melt until 2 or 250 degrees.

Hello Coxaddict, are you talking about the black backplates on the 049 airplane engine with the metal fuel tank or the straight up plastic type with the brass needle valve? towards the later years Cox used what appears to be a Bake a light type plastic on the back of the airplane engines, I thought the  the Black horseshoe design came on the cox RC cars like the Nissan GTP. I would suggest just stepping up to the Killer Bee backplate from Bernie here, I am interested in trying them on a Car engine. Ken Cook is the Wizard behind the cox Airplane engines and has gratefully shared a lot of fine tuning and speed secrets to me. Also, You airplane guys benefit from having all that air rushing past the engine were the Cox Car engines do not really have much in the way of cooling features.

My "black-plastic" horseshoe carbs/backplates suffered from rupturing in the area where the steel/music-wire "circlip" reed-retainer was used.





There may have been some crashes which could have caused the "fractures" seen in the above photos. An unplanned "nose-in" to terra-firma would jam the crank-pin into the backplate; weakening-it considerably.. as opposed to the more sturdy aluminum "integral-tank" assembly of the "Bee engines". A positive feature that can't be ignored..

Wow that's incredible I no that I've blown up a couple Cox car engines over the years but you are plain guys have your issues to contend with two try to rebuild the airplane engine and get that bad boy back up in the air

Bill steklenski wrote:Thanks so much for posting that info, I have met many DuPont Representatives over the Years but it all pertained to the Auto paint chemicals.

You're welcome, Bill. About 2 years ago did a motorcycle tank repair for a friend, used 2 part Dupont Ful-Thane, was impressed with how the paint finished out. Dupont may cost a little more but does a nice job. PPG may be a little cheaper, but I don't do enough work to justify changing, then have to buy new thinner, hardner, etc., more out of pocket expenses.

If one of you guys truly wants to see what I call the Bulletproof Backplates the Cox 191-4 Jeep engine would show the best example. I am claiming that the very Early backplates are Delrin based on what I was told.

The red plastic ones seem sturdy, I still have a few from donor engines in the late 1960's, postage stamp backs. Used CG postage stamp mounts since engine lacked mounting lugs.

Also, when I just Googled Delrin Properties the Technical information was different than what I saw before, I thought Delrin did not start to melt until 2 or 250 degrees.

I did a little reading various articles on the Dupont website. Impression I got is there are various grades of Delrin with different temperature and strength properties, which might explain the differences you observed.