Fox 35 collectors edition

I like the finish on the 40th anniversary and the late 80,s there a matte finish that’s what I call it but really looks good I agrethe 40 is a good looking engines if it runs as goad it looks. I have the 50th and the 60th both I have ran yet. This cancer just got me checking them out and ready a lot   I miss flying.  Breathing is messing with me so I mainly just admired the engines and read. I have plane I still haven’t broke maiden flight yet.

Picture 1954 19

Why didn’t they paint all the rockets red ?

The 40th was the last year of the old style muffler attachment with the small ears on the case. These will break quickly in even a minor flip over. I usually use steel brake line and JB weld it to the side of the case between the ear and the muffler. This insures that the ears don't break off. The 50th and 60th case have been redesigned with the material all the way to the face of the exhaust stack. This addition of material was not cast when the case was made. It was done later and that entire piece won't break off, it can come loose. If you look carefully at the case, you can see what appears to be a mold line. In fact it's a cold joint. I believe there's small dowel pins inside that material because when using the stock POS muffler that comes with the Fox, it's too heavy. Overtime, vibrations, combined with the weight can cause the entire side of the case to come loose where the muffler attaches.

Fox offered a warranty that was terrific. They never charged labor to repair your engine. This wasn't some bs line written into the warranty, they never charged money. If, your engine repairs exceeded 1/2 it's cost in parts, you were offered another engine at 1/2 the price retail price with yours in trade. You did have the option to retain your engine, you just paid the difference to repair it. If you wanted to purchase a new engine, ANY engine could be traded in , running or non running for 1/2 the retail cost. I would purchase several engines at a time. I upgraded all of my older Fox's to the newer style case. The exhaust stack on the 50th and 60th case is slightly different than the 40th. It's not off by much but enough it requires a needle file to open the holes. This isn't really true for Fox mufflers, mostly my tongue mufflers I use.

Reading your post, you mentioned using the black spraybar and needle assembly as a hop up for a Stunt.35. Using that needle would decrease performance. The stock spraybar assembly that comes with the Stunt.35 offers the most power due to it's size in the throat area of the venturi. Even the Enya assemblies Shtterman offers on EBAY are incorrect. They fit the case but the spraybar diameter is larger. It decreases the performance. Randy Smith offered the PA needle valve assemblies which were specifically made for the Stunt .35. I have no idea why he doesn't have another batch of these made. They were $18 dollars for a assembly when he offered them, I'm certain they would be double now. Seeing how MECOA wants to break it off in your rear end for $30 for the stock version which is worthless, I would venture Randy Smith would recover his money quickly.

Case in point.
I do see a very slight difference in the Mount for muffler I would have never seen it. There seems to be a small spacer behind the ear on the 50th.
Randy Smith if it’s the same Randy i have some conversations with I wasn’t aware of the NVA. Thanks I will check. Maybe it is.  The RS I talk with is in process of selling off some engines.  It would be nice to get a few of them. I put those NVAs on just to try and keep things as close to original never thinking about Proformance which I should be. Thanks again.

Disregard Got it. Same deal with wrist pin. Thru me off no hole in case


Not to change subject but on this 15x do you know what side the hole in the sleeve goes on in engine? I always take things apart then forget how it goes back together.

Just thought I share a few of new engines. Any info would be greatly appreciated thanks.

New engines

They did a beautiful job on that anniversary model, nice clean casting.

Yes they did , it’s a work of art. It also has a abc liner and heavy back plate. The 35 with the black head and the 40 I’m not sure about. The 35 has that exhaust blocked , don’t know what that does but it also has a new liner but stock and a heavy back plate. I will try and get out in the next few days and bench run. I plan on using 29-5 mixture none are broken in .
I forgot the 35 with the black head has the slanted plug also

Onelife wrote:Not to change subject but on this 15x do you know what side the hole in the sleeve goes on in engine? I always take things apart then forget how it goes back together.

Can't get to my R/C version "X" right away, otherwise could let you know.

I think it may have been @Ken Cook who explained what the hole in the sleeve was for, may be related to piston pin removal.

On occasion I've done just as you did and then am left with a little reconnoitering to intuitively figure out orientation. The exhaust port cutout is always higher than the bypass port cutout for the combustion chamber. By slowly trial fitting and reorienting before final assembly, will find a way that then everything makes sense.

Yes Ken did explain thanks for the reply

Paul, this is some good information on the Fox .40. The write up calls the case the C frame case but I refer to them as coffin backs. A lot of this info is pertinent to even the Combat Specials.
                             
             http://www.flitelinesolutions.com/project4.html I don't know exactly why this link isn't working but copy and paste it. Good reading information


        I also noted that your .40 is the last of the .40's utilizing the newest needle valve. This same needle was offered on the Fox .35. After 60 years they figured out how to make a needle valve instead of the piece of crap they offered. Unfortunately, the newer needle valve couldn't be swapped from one side of the case to the other. You also couldn't put the engine lug bolt in without removing the needle valve. I have one new version which is a remote needle but the quality is good, it offers a o-ring seal which does work as intended.

Question is this other 40 a silver Fox? And the Venturi looks like the needle value should be up closer to the top is it in backwards?

Understand that Lew did most of his mods internally. The Fox .40 is a two piece head. Lew would reconfigure the squish band of the head button. Later Fox .40's offered same or close to the same configuration as to what Lew did. In addition, I think Lew changed the liner height and did some mild porting changes to the liner.

As for the venturi stack on the .40, remember you have a r/c case and a control line case. The version you show in the book is the control line version and the reason for the two casting areas for the needle on the stack is for a purpose. The venturi is quite large on these engines. When you mount the engine profile and the cylinder is on it's side the needle when it's on the bottom hole is closer to the crank. This causes a lean condition and makes it more difficult to draw fuel when the tank pickup is further outboard. Moving the needle valve higher on the stack solves a little bit of the fuel draw issue.

Thanks Ken I am gets diagram on the workings Lew did internal. I’m surprised myself to even north’s different locations in the first place lol. Such dedication that was put into the Fox is really amazing. The 40 really bumps things up a notch.
And as far as the 2 piece head I was curious if it had a hemi but I am even afraid to take out the glow plug for fear I will break something. So Lew even did modifications there too. I want to take the head off and look but I’m all thumps somtimes if things get stuck. I am more aware of putting head back on now since coming to forum and your help thanks  what glow plug and prop for break in should be used ? And mixture of fuel ?

As much as there's many Fox haters out there, the .40 was monumental. Understand that Duke was the first to cast a engine case in a single piece and do all the bypass milling without splitting the case in two pieces. In 1976 Duke offered the first coffin back case which was the FOX MK III Combat Special. Fox shared the design with almost all of the engines offered from .29 displacement on up until their demise.

The head design is also a very simple design. DON"T USE nitro above 10% with the older head button as it won't do damage, it just won't run very well. The newer button can tolerate a fair amount of nitro. The problem with Fox engines is that he never pinned the cylinder liner. Tightening the head can rotate a liner slightly thus misalignment can occur with the piston if the engine has been run. The Fox head button on the earlier variants were TERRIBLE. Just like the Combat Specials, they were essentially flat with a hole in the center leading up to the plug. This would rip the guts right out of the plug in one flight. To prevent this, I was jacking up the head as much as .030" to reduce the compression. This is another reason NOT to use a lot of castor as you don't want to up the compression any more than what it is. 20% oil is all that's required. The later head button was a hemi which was good but then they offered the double bubble as reffered to where the the head button was hemi'd and then done again in a larger radius bringing the squish area out further.

        I met Lew at Brodak's a few times. Lew was a neat old fellow and he was also a flyer who did quite well. One thing I can say is that he was not afraid to tell you how or what he did to the engines. He would also tell you how you could make it worse if not careful. I own several Fox .40's in iron piston and ABC. To be fair, I own them because I like them. I've never flown them with the exception of one.

      Fuel and prop requirements are simple. The range of props for the .40 is 9x6 to a 11x5. Most use a 10x6 with a Fox .40. I generally drop one inch in diameter and drop one inch in pitch when going for initial run in. Either a 9x5 or a 9x6 will suffice. The .40 was made in iron piston and ABC. It was also offered with a single rear main ball bearing running in the aluminum in the front and a twin ball bearing on the later version. Either or, I personally use 5% nitro and 22% total oil content for all of them and I use 50/50 castor /synthetic and I've been doing so since 1990. Fox recommends castor at least 18% castor 2% synth for the iron piston. It doesn't matter in my opinion as long as your oil content percentage is correct, these are STOUT engines and your not going to hurt it. What will hurt one of these engines is the circlips that retain the wrist pin. They can and have been known to come out. I've seen this happen and I've had it happen on the Fox .15 BB versions which are essentially miniatures of this engine.

. I own several Fox .40's in iron piston and ABC. To be fair, I own them because I like them. I've never flown them with the exception of one.
I like that and and think they are very interesting engines.
My second Fox 40 just by looking into exhaust port isn’t brass so I’m guessing it’s steel. As far as the bearings go I have to dig more and find out exactly what in the two I have. 1 is brass and one is steel.
Thanks for the info on the mixture and props Ken.