earlwb

For the old two needle butterfly valve carbs.
I had posted some assorted Fox engine manuals here a while back http://www.rcgroups.com/forums/showt...955929&page=11
Any of the Fox .40,45, 60 and 74 engine manuals would work for the .50 as they pretty much all used the same two needle butterfly valve carbs.

If you haven't take apart the carb and or messed around with the needles then you do not have to do anything, as it is still setup from when it was last run.
But the basic method was to set the high speed needle in 3/16" of a inch from the end of the clips and set the low speed needle in 1/16" from the end of the clips. That would get you in the ball park for adjustments.

I wouldn't worry about the peak RPMs, the Fox .50's run really good. It depends too much on what muffler you are using. Just tune the engine so it is about 500 to 1000 rpms off of peak. Point the nose of the airplane up towards the sky and adjust the peak RPMS and back off a little.

Sport_Pilot

The .50 used a rotating barrel MK X carb.  They adjust like any other two needle carb.  

earlwb

Good point, I keep forgetting about the MK X carb.

Recycled Flyer

Try here -
http://controlline.org.uk/phpBB2/vie...lding+mufflers

This is a friend of mine with years of modelling experience talking.

Tarasdad

For the first time in 20 years my Fox .50BBRC came to life today! All it took was a new glow plug, fresh fuel (Byron's 10%, 2 oz. Sig castor added to 1/2 gallon) and a hit from my starter and off she went! I kept it running slobbery wet as I'm seating a new piston ring. The entire right side of the plane and the table I was using were dripping with oil. Still, I'd rather have an oily mess than a fried engine!

I still need to tweak the low speed needle to lean it out a bit. Loads up and bogs down in the mid-range. Won't worry too much about that until after I'm satisfied the ring is seated properly. One thing I had forgotten is just how powerful this gem of an engine is! Plenty of thrust turning a 11x6 Zinger!

Can't wait to get this bird (CG Tiger 60) into the air!

earlwb

Cool.
Yeah super rich is good for a while as it oils up the bearings and helps to flush them out good, plus it helps to flush out anything else that could have been inside too. After many years of sitting, the old congealed castor oil can leave some bits and pieces about on the inside.
The Fox 50 BBRC engine can turn a 11x7 prop as well if not better than some of the old baffle port .60's could. But only after it is broken in real good.
It likely outperforms my old Fox blue head .60 I happen to have on a Tiger .60 clone plane too. The old engine works but it can be messy after a lot of flying.

Tarasdad

LOL yep, that's exactly what the side of my Tiger looked like after a tank of fuel. I had forgotten just how much fun cleaning up after could be. Still, nothing can replace the smell of burned castor, can it?

Recycled Flyer

Earl, is that frost I see on that grass?

Cougar429

My Feedback: (3)

I know how that feels. I did the same with my 50BB after a 20+ year storage. However, even though stored in an oiled plastic bag I did open it up and give it a rinse with alcohol. Only thing I found was some crud from the fuel system had made its way into the carb on the second or third tank. Should have done the same flush with the rest of the fuel system.

rrengineer

My Feedback: (3)

What's the difference between two Fox .29 RC engines where one has a rotating flap in the exhaust and the other does not. I'm guessing the one with the flap is an older version. When did they change to no flap? Will one with the rotating flap work OK with a muffler installed? I am guessing there are other subtle changes internally between the two also.
Mike MacLean

Tarasdad

When I got my engines from storage at my dad's house in 2006 I took them apart nd gave them a thorough cleaning. Worst part was getting all the gummed and hardened castor out. Once clean they were oiled up and stored, bu this time under more controlled conditions - big difference between the SE Texas climate at my dad's house and here in the Mojave Desert of Southern California. In 2010 the .50 received a new piston ring, gaskets and had the carb rebuilt. It sat that way until yesterday. I can't tell you how happy I was hen it fired right up, almost like the intervening two decades never happened!

Fox builds a tough engine! Now if only my luck holds with my Saito .80. I'm not worried about the Fox .25, that little sucker seems to be bulletproof!

earlwb

Yeah it was a cold day out that day. I got a lot of flying in as no one else braved the cold that day.


But it was a lot harder to get the cold oil residue off the plane when I quit flying though. The cold turned the stuff into something more like grease.

earlwb

Actually no differences between the .29 engines. They did do some external mold casting changes as they wore out old molds.
When the .29's first came out no one used mufflers. Later they came out with the RC version and it needed a exhaust baffle to help with idling.At first with the primitive RC systems, about all you had was low speed and high speed. Later they improved the carbs as RC systems advanced and became better. Along the way mufflers became something that was required to help reduce noise levels. The first mufflers had a cutout in the flange to clear the exhaust baffle, which is why you use the two top and bottom center mounting holes in the muffler. Later engines dispensed with the exhaust baffle as the better carbs didn't need it then. But later they came out with the side mounting tabs and quit using the center top and bottom holes to bolt on the muffler with. Usually the top and bottom holes aren't drilled and tapped for the muffler, but some early versions of that style engine did have the holes drilled and tapped for the older style mufflers.
As far as I can tell, the parts for the newer .29's still fit in the older .29's. They didn't really change anything internally of any importance. But then maybe they did, I never tried mixing and matching parts in one.

rrengineer

My Feedback: (3)

The .29 I have does not have the exhaust baffle, so I guess it is a later engine. What it does have is a Perry carb. I have not run it yet, but from what you say the Perry carb is an improvement. Just have to figure out a muffler for it.
Mike

Bob Paris

My Feedback: (13)

Hi Guys,
I've been running my Fox .50's for years and they just get better with age. I just pulled a K&B .40 out of an Ugly Stick Bi-plane, and installed the .50. What a difference it made... I had that engine in a Telmaster 70 for years and gave the model away to a buddy...but kept my Fox .50. I run a Perry carb on this engine and I've run that carb for years with excellent results. The mid range is good and it will idle so low it will amaze you. Lots of power and I use a Pro Zinger 11 x 5 prop on the engine. I also have a couple of Fox .15's and these little engine are amazing and powerful.
Soft Landings Always,
Bobby of Maui

earlwb

The first Fox muffler had no flange, but it had two tabs in the middle on the top and bottom for mounting to the engine with two screws. That let it clear the exhaust baffle, if the engine had one. The next muffler was basically the same but it had a flange running round the inlet, so it slipped onto the exhaust outlet and didn't move around as much. It still had a notch on each end to clear the exhaust baffle. The third type had mounting tabs on the sides and top and bottom as the newer engines only had the side mounting tabs. The flange allowed one to remove the exhaust baffle and not have to come up with a couple of plugs for the holes where the baffle used to be. The same Fox muffler fits the .19, .25, .29, .35 and .36 RC engines. But some earlier .19 engines didn't fit it as well as the earliest .35 stunt engines.

It is easy to hook up a MAC's One piece muffler like the 6340 to the engine. If you don't have the side tabs on the engine you either go with a water hose clamp or a thin metal strip around the other side to use screws to clamp it on with. The Fox .35 stunt tongue muffler works also, in the same way you could use the Mac's muffler. The old Tatone and Streamline mufflers have clamp on versions that are easy to hook up too.

rrengineer

My Feedback: (3)

The .29 I have has the holes top and bottom of the exhaust port, but no tabs on the side. There is no exhaust baffle. I have bought the Macs muffler you mentioned and will use a strap I have from an old Enya .29 to secure it to the motor. I also have a chance to buy a "new in the box" Fox .29 that has the exhaust baffle, but no muffler. I'd like to get it, but putting a muffler on it with the exhaust baffle presents a problem. Maybe I could plug the baffle holes with J&B Weld and buy another Perry carb for it.
Mike MacLean

earlwb

Yeah I have used JB Weld before for that on a engine, it was my old Fox .78 engine. I use some masking tape to block off where I don't want the glue to go.  But now I have a small lathe, so I make up some aluminum plugs for the holes instead. The clamp keeps the plugs in place for me.

rrengineer

My Feedback: (3)

Wow! Nice neat job and reversible too. By the way, I have not run a Fox .29 in many years. What nitromethane percentage is appropriate for this engine?
Mike

earlwb

Most any nitro-percentage you want to use is fine with the engine. From 0% to 25% nitro is fine.
I would suggest either all castor oil or a blend of synthetic and castor oil in the fuel. Fuel with 20% oil is fine, 18% tends to get iffy, but if the engine is broke in then it should be fine. Most modern fuel brands are using 17% to 18% oil content nowadays, so you have to check the fuel labels or brands and type more carefully nowadays.
I normally add extra castor oil to the fuel for my old engines, just in case. I use a old quart fuel container and mix it a quart at a time for the old vintage engines.

Tarasdad

Made it out to the field this morning. Initial flight the engine ran a little rough. Tweaked the high speed needle a bit and all was good. Managed three flights all told, and by the end of the third she was purring like a kitten!

Cougar429

My Feedback: (3)

What prop are you swinging on the 50?

Tarasdad

Using a 11x6 Zinger. Seems to do really well with that prop. I also have some MA 11x6 props but don't like those as much as the Zinger.

jeffie8696

Can somebody let me know if the Fox 40 RC Sport Model: 40024 is a bushing engine or bearing? Fox isnt real generous with information on its website. Isuspect its a bushing engine but I am not predjudice against bushing engines. Heck some of my best runners are bushing engines.

Cougar429

My Feedback: (3)

Does your 40 have the tapered or four-splined drive washer? I have the four-spline and it has the oddball SR6-5 front bearing. BOCA is pretty much the only source for those. In their listings the tapered collar is also a bearing motor. As they would obviously not list a bushing style no guarantee if that covers the entire fleet.