Calling all Fox fans

Oldenginerod Fri Jul 08, 2016 1:45 am

I decided to dismantle & clean up an old Fox .40 I was given years ago. I recently got a full overhaul kit for it.
My question is, which way up do the cooling fins go? Here's mine prior to clean-up, showing the wide fin at the top (just below the head).

Here's one I found on-line from the J.M. Rojo Collection, clearly showing the thicker fin at the bottom.

I can't really see that it will make any difference, but I would like to have it assembled as Duke intended.

Rod.

Ken Cook Fri Jul 08, 2016 3:35 am

Thicker fin at the bottom, These in my opinion worked very well. They were light and short and they make a good control line engine. I gave one of these away some years ago and wish I didn't. You just don't see many of them around nowadays.

balogh Fri Jul 08, 2016 5:17 am

Looks like the thick fin is at the bottom as Ken says:

http://www.sceptreflight.com/Model%20Engine%20Tests/Fox%2040%20RC.html

Oldenginerod Fri Jul 08, 2016 6:55 am

Thanks guys, that'll do me. Engine is all cleaned up & ready to go back together with new gaskets & screws. I don't have a plane big enough for a .40 so it'll be bench run only, so no point cosidering a C/L conversion.
By the way Ken, how do you convert the carb to eliminate the throttle for C/L, or do you just wire the throttle open?

Ken Cook Fri Jul 08, 2016 2:47 pm

Fox offered a venturi stack for the engine. It looked just like a piece of aluminum tubing with a angle cut on the front facing the wind. The tube had a hole through it to hold the needle valve.

**RknRusty** Fri Jul 08, 2016 11:55 pm

That's an interesting read, thanks Andras.

I wonder if this is a misprint, either way, I've not heard of this alloy; Meehanite, from which the piston is machined. Maybe it's supposed to be "Mechanite." Also the annular rib above the wristpin bosses sounds like a good idea, do other Fox pistons have this reinforcement?

I will have to read the rest later, the type is pretty small.
Rusty

balogh Sat Jul 09, 2016 12:05 am

Rusty

This Scepter flight stuff with tons of engine tests is accessible at the bottom of Instruction sheets page of CEF . See the Info section on the left of this page..

Oldenginerod Sat Jul 09, 2016 3:38 am

Ken Cook wrote: Fox offered a venturi stack for the engine. It looked just like a piece of aluminum tubing with a angle cut on the front facing the wind. The tube had a hole through it to hold the needle valve.

I'm not sure how you'd install it as the carb looks to be either pressed or bonded in, maybe glued?? I guess, once you could figure out how to remove the carb body, you'd just have to glue in the venturi tube.
I'm surprised at the small intake on the carb. I would have expected larger on a .40.
Rusty mentions a reinforcing ring inside the piston. I didn't go far enough to confirm that on my engine. The gudgeon (wrist) pin is retained by two tiny "e" clips, far too small for me to try to remove, and more importantly, refit. As such, I wasn't able to remove the piston/rod asembly from the engine, meaning I also couldn't remove the crank, but that shouldn't be a problem as it all cleaned up fine. The piston is still a really firm fit in the sleeve with no sign of wear in the big or small ends, or the brass case bushing. If it has done any amount of work it has been treated kindly, or has stood up really well to use. It's certainly no beauty contest winner, but if I can figure out the complex carb I'm confident it will run ok. Actually, when I first had it given to me I squirted some fuel in it, hooked up the battery, gave it one flick and it burst into life in my hand, so it can't be too bad.
I'll get some photos once it is reassembled.

pkrankow Sat Jul 09, 2016 10:06 am

https://en.wikipedia.org/wiki/Meehanite

Trademark processes...
Phil

GallopingGhostler Sat Jul 09, 2016 10:43 am

Just wondering if that in order to keep production costs to a minimum, that Fox competitor Testors Corp. went to a softer non-Meehanite iron piston to avoid licensing fees? Tired w/ Coffee Read

Oldenginerod Sun Jul 10, 2016 12:39 am

Done! Not as pretty as some, but this engine is never going to be pretty. Went back together nicely & feels tight & strong. A slight lap of the piston & carb barrel with brasso and all's smooth. Next, to fire it up when I get a chance.

Rod

GWILLIEFOX Sun Jul 10, 2016 8:01 am

The inside of this engine has lots of surprises

Ken Cook Sun Jul 10, 2016 8:32 am

I love in the instructions where it states to run Missile Mist. I loved that stuff, the magical purple brew. I don't recall ever running my .40 on fuels over 10%. I bet that would be some fun. It would certainly move out on that stuff. Missile Mist and K&B 1000 made some very entertaining flying.

Oldenginerod Sun Jul 10, 2016 5:22 pm

GWILLIEFOX wrote:The inside of this engine has lots of surprises

Yes, I was a little surprised by the complex looking porting. A little beyond the ordinary single by-pass baffle type engine I'm used to.
Lots of room to breathe there.

Paulgibeault Sun Jul 10, 2016 6:09 pm

Rusty wrote:I wonder if this is a misprint, either way, I've not heard of this alloy; Meehanite, from which the piston is machined. Maybe it's supposed to be "Mechanite." Also the annular rib above the wristpin bosses sounds like a good idea, do other Fox pistons have this reinforcement?

Rusty: Meehanite is a type of iron that many pistons were made out of at the time. They ran reasonably well in steel cylinders... Cheers, Paul
p.s. I even own one of these Fox .40 C/L engines...

batjac Sun Jul 10, 2016 7:47 pm

Ken Cook wrote: Missile Mist and K&B 1000 made some very entertaining flying.

Last week I was cleaning up, and found a quart can of K&B 1000+ that's mostly full. I don't know how old the stuff is, but I'll strain it into another bottle and see how great it runs.

Mark, The Discoverer

pkrankow Sun Jul 10, 2016 9:05 pm

If it is clear it is worth running. Black means the can went bad and the fuel is contaminated...but it will still run if you are willing to risk it.

Phil

GallopingGhostler Sun Jul 10, 2016 9:43 pm

Paulgibeault wrote:I wonder if this is a misprint, either way, I've not heard of this alloy; Meehanite, from which the piston is machined. Maybe it's supposed to be "Mechanite."

Meehanite is correct, there is even a website for it:

http://www.meehanitemetal.com/

http://www.meehanitemetal.com/htmlpages/whats_diff.html[/mention] wrote:Expressed in it's simplest form, Meehanite metal is first melted to a definite degree of undercooling or constitution which is related to the section of the casting to be poured and the range of physical properties such as tensile strength and hardness required. Nucleation with patented mixtures of graphitizing agents results in the removal of undercooling, in the controlled precipitation of graphite and in a fine grained eutectic cell structure which determines the density and physical integrity of the casting. Ordinary cast irons made to chemical specifications which do not include the benefit of controlled undercooling are influenced by mass effect to a maximum degree and for this and other reasons cannot be considered an equivalent to Meehanite metal.

Oldenginerod Sun Jul 10, 2016 9:56 pm

pkrankow wrote:If it is clear it is worth running. Black means the can went bad and the fuel is contaminated...but it will still run if you are willing to risk it.

Phil

Dang, I hate it when you type a reply and it disappears.
Anyway, what I said was, even if the fuel is clear, give it a shake and see if it goes cloudy. If so it has absorbed moisture. Still hang on to it for cleaning up parts.
I had an old bottle of fuel someone gave me. It looked fine but the bright red oil had settled to the bottom. When I shook it to mix the oil it went cloudy. I suspect that high moisture content meant the oil couldn't mix, but emulsified with a shake. It still fired up for bench testing but I mainly used it for soaking dirty engines in it.

Rod.

**RknRusty** Sun Jul 10, 2016 11:24 pm

Paulgibeault wrote:Rusty: Meehanite is a type of iron that many pistons were made out of at the time. They ran reasonably well in steel cylinders... Cheers, Paul
p.s. I even own one of these Fox .40 C/L engines...

Thanks Paul and George, I did not know that.
Rusty

706jim Mon Jul 11, 2016 4:39 pm

batjac wrote:
Ken Cook wrote: Missile Mist and K&B 1000 made some very entertaining flying.

Last week I was cleaning up, and found a quart can of K&B 1000+ that's mostly full. I don't know how old the stuff is, but I'll strain it into another bottle and see how great it runs.

Mark, The Discoverer

There is a thread on RC Groups regarding glow fuel life. I thought it would expire when it hit the 1000 post count, but nope, still sputtering along.

http://www.rcgroups.com/forums/showthread.php?t=2639766&page=75

Marleysky Mon Jul 11, 2016 6:40 pm

706jim wrote:
batjac wrote:
Ken Cook wrote: Missile Mist and K&B 1000 made some very entertaining flying.

Last week I was cleaning up, and found a quart can of K&B 1000+ that's mostly full. I don't know how old the stuff is, but I'll strain it into another bottle and see how great it runs.

Mark, The Discoverer

There is a thread on RC Groups regarding glow fuel life. I thought it would expire when it hit the 1000 post count, but nope, still sputtering along.

http://www.rcgroups.com/forums/showthread.php?t=2639766&page=75

Wow, they sure know how to beat a dead horse over there, don't they?? I think that thread is about 1001 posts too long. Like to argue for the sake of argument? I quote:
"Wow, now it's up to 511 posts for a non existent problem if one keeps the container sealed."
I Love This Forum!

nice people, polite people helping others.

Oldenginerod Fri Jul 15, 2016 9:23 pm

Just a quick progress report on the Fox 40. I finally got some time to run some engines today. First fine day for a while and everyone was taking advantage of the drier day to mow their lawns, so my noise would fit right in.
Mounted up the Fox on my test stand. I'm not even sure what prop I have fitted as it's not marked, but I'd say about an 11X5.
Apart from my 25%/25% 1/2A fuel, I only had some buggy fuel that I use to blend the raitos I need. Couldn't be bothered mixing up the right brew, so stuck with the 16% nitro and 18% synth/castor blend. Figured it would do for a bench run.
It fired up pretty easily following my rebuild. The engine announced its agressiveness right off the bat. It has heaps of compression and you need to be quick with a well protected gloved hand. My starter struggled on a low battery to get it over compression without a run-up.
I employed my sketchy knowledge about these twin needle carbs and got the idle set up first. The needle is very sensitive. After a few tweeks and restarts I managed to get a pretty reasonable idle, peak and transition. The engine ran strong & steady, so I'm pretty pleased with that.

GWILLIEFOX Mon Jul 18, 2016 6:57 am

Nice work on bringing your old Fox back to life. Here's an original ad fo

r it from the Sept. 1971 RCM:

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