GallopingGhostler

I have a broke in Enya .19-VI TV and a new unused Fox .25 cross scavenge baffle piston with MKX carb. Data shows the Enya at .42 hp as CL and .36 hp as RC. Fox is shown as .45 hp. Recommended props for either are the same, RPM's are about the same.

Sometimes provided data can be deceiving. Is the Fox more powerful or are they about the same? It's for a .20 sized warbird.

controlliner

There's no replacement for displacement.

GallopingGhostler

Well, yes, I understand your point, controlliner. Overall it is true but sometimes the inner construction affects the outcome. (Example, McCoy Black Head .40 shows a lower HP rating but swung a 12x5 wood prop on bench like it was made for it. )

There's a reason why I asked, which sparked my curiosity. For example, the Enya data shows

19-VI CL: 0.42 hp, 8000-16000 RPM; RC: 0.36 hp, 2500-14000 rpm; Props: CL 8-9x6-5, FF 9x4, RC8-9x6-4

For the Fox shows:

25RC: 0.45 hp, 2000-13000 RPM; Props: FF 9x4, RC 8-9x6-4

I know that results can be affected by the fuel used, so the numbers alone can be deceiving. I bought the Fox prior to the .25 being discontinued, because I like the cross scavenged engines better than the Schneurles (swing larger lower pitched props, etc.). I also gathered that the Foxes were good engines, albeit sometimes a bother to properly break in (iron/steel - piston/cylinder liner construction).

Hobbsy

My Feedback: (102)

George, paper HP tells you absolutely nothing, flying HP is what counts and the Fox will have more of it.

PS, the Fox .25 is alive and well.

http://www.foxmanufacturing.com/inde...roducts_id=281

earlwb

Mr Duke Fox once lamented that people were preferring and buying the Fox .25 engines over the Fox .19 engines. But in real life the .19's didn't really perform much less than the .25's did. So basically the .19 is about the same as the .25 engine in performance, there is only a slight different in real life running the same propeller on both. Buit then Fox may have had a lot of .19's that weren't selling too and he was doing a little marketing there.

Now then OS played that difference in engine displacement up with some great marketing and was outselling some competitors by making engines with a slightly larger displacement. People have a tendency to perceive a performance increase if the engine has a larger displacement. But with model engines the different between a .19 and a .25 isn't all that great. About like a Cox .049 engine difference in displacment.

Anyway, if you have a nice running Enya .19 then by all means use it. No sense having to break in a Fox .25 as it might take a while, unless you have a use for it.

tiffitech

Enya's HP Numbers are always on the lower side... you get more out of them easily.
(I don't own any Fox and the statement above is only from reading some test results)

Regards,

Holm

MJD

My Feedback: (1)

The hp quoted is only valid at one rpm, which will undoubtedly be the rpm at which peak power is produced. The number tells you very little about how it will perform on that range of props. Each engine has a unique torque/rpm curve - a function of internal design, carb specs, exhaust system, bla bla, and despite the displacement difference the .19 could equal the .25 on some props, or it might not touch it on any of them.

Point being you cannot tell any of this from the data above. Variables are missing. The range of props may be the same, and the operating range may be in the ballpark, but all you can infer from that is that they both run well on the same range of props and both are timed and set up to run at sport engine rpm. Beyond that there is "insufficient data" to know how each will turn a particular prop.

That's why this type of seemingly complete info is so typical in marketing literature - it leaves out enough that it is difficult to make a negative judgement. Quote peak hp and peak hp rom and people get all excited. However, rarely are those sets of conditions used in normal use.

The only manufacturer that fills in the blanks that I know of is Jett, who publish real world baseline rpm numbers based on a specific fuel and specific prop.

GallopingGhostler

Thanks for the inputs, Hobbysy. Yes, I kind of gather that, but even among cross scavenged, a seemingly underling such as the Enya .19 could hold its own, if you know what I mean. The one you show is the Schneurle ball bearing version.



It is a sweet engine I gather, very desireable and powerful at least in my estimation. The one I have precedes it, a non-Schneurle cross scavenged plain bearing one.

GallopingGhostler

earlwb, what you say makes a lot of sense and supports my gut level feeling. Yes, I'd rather go with the Enya since it is already a good running engine. I've got a place for the Fox, a Tidewater Pronto future build.

GallopingGhostler

I couldn't agree with you more, there MJD, it's why I asked. I have no experience in running Fox engines. This is the only Fox I have, but I bought it some time back when I heard good reports about it especially with their newer MKX carb.

Holm, yours and earlwb's inputs have convinced me to go with the Enya. Thanks all for your inputs.

1QwkSport2.5r

Enyas are hard to beat. They just run and run and run. I'd vote Enya also.

GallopingGhostler

I got to admit there, earlwb that in real life this marketing that bigger is better seems to permeate all facets of life. I've got a 650 motorcycle that I've cross country'd a good bit. Marketing and friends tell me that it is too small, I need a bigger motorcycle.

GallopingGhostler

That's what I gather, 1QwkSport2.5r. This Enya I've got seems to have no nasty habits, is a smooth running well throttling engine with plenty of power, swings a 9x4 like it was made for it.

AMB

The new Fox 25 is Schneurle ported nothing wrong with the baffle piston great engine you will not go wrong with Enyas, I have their CX11D and 25D martin

1QwkSport2.5r

I've heard of many people finding Enyas in the dirt (some literally) at the field... Clean 'em out, fuel 'em up, run it for 20 years. LoL. They really like running on as much castor as you can throw at them too. Even the 4-strokes.

1 Pitts Special 1

I have used both brands an cannot knock either as a weaker engine. Both do have a good history of long life spans. But when it comes down to it all I will take the Fox. While in control line flying the durability of the Fox is legiondary. A sparkle of hp on one will not be noticeable in flight. The timing in Fox CL engines is about as dead on as can be. I've moded them in many ways an still very little was to be gained in CL. Unless you did a complete smoothing job with extra porting which is not worth the effort.
Trying to get parts for Enya is more expensive ordering from Japan. Fox is American made an parts are quick to get. Their service has always been top notch for me.
The difference in flight will be noticed with different props an it takes time to get it right. Every Fox I have owned over 30 plus years has taken some time to break in. My first CL .19 took close to three gallons to get stable. Erratic as could be but after the long break in an close to a thousand flights, it finished its life with a friend on a Sig Akrobat.
My rc planes were largely Fox with some OS an Enya's. but after my local shop stopped carrying glow plugs an parts for them I stayed with Fox an have not regretted a day of it. Tuning is where most people fail in engine success an don't take time to learn it an hate glow engines. They don't come from the box all broken in, their just new. I could not tell you the numbers of Cox .049 with scorched cylinders I was asked to look at.
In CL be precise in actions on the control. Total all out performance is not going to gain point from judges. Can you fly the pattern an set the engine up right, minuscule amounts of power gain you nothing except I in racing. Don't get caught up in his is turning faster or stronger mess. Many engines will out turn a Fox .35 stunt but look at the wins still coming.

earlwb

Both the Enya and the Fox engines are known to last seemingly forever. Barring a nasty mishap either engine can go more than a 100 actual hours of usage. the Fox MK-X style carb is actually really good. its only flaw is that the low speed needle is easily accessible and visible. People just seem to cannot resist trying to adjust it and screwing up everything. Like usual people don't seem to read the instructions on how to adjust them. Once the low speed is set you seldom if ever need to touch it again. Just the high speed needs tweaking and if adjusted Ok it is only when there is a major weather change, such as summer to winter and back to summer again.

OS sort of solved the issue by hiding the low speed needle inside the throttle barrel where people didn't notice it. Since most people don't read the instructions they didn't see it or mess with it. Fox on their latest carburetor for the .25 on up sizes of engines, went with a design that has the low speed needle hidden too. In my experiences with the new carbs, they work really well, so much so I took to retrofitting the new carbs on older engines even. In the engines I put them on and use them on, I don't remember really needing to tweak the low speed needle any.

One nice thing I liked about bushed crankshaft engines was that they had no ball bearings to go bad on you. You could shelve a engine for years, pull it back off the shelf, unstick it and oil it up good, and go out and use the engine once again. No worries about bad corroded ball bearings to replace. Granted they don't develop the speed or power that a fancy ball bearing engine does, but they last and wear much longer though.

1 Pitts Special 1

Earlwb you are so right about those carbs. Two things I never liked about Fox was the needle valve adjustment on CL an RC motors an carberators. If you remember the needle on CL engines had that flat blade on the end. I would take a drill an mount the needle in it, being careful to insert it in tubing to keep it straight. With a small file or stone from a dremel with drill on low speed, take it down to a needle point as with other brands. I never understood Fox's design on that. The sharp point as you find on OS, Super Tiger, an everyone else I can think of did not use that blade type. The improved needle worked wonders for everyone's engine we preformed that little trick on. You had to becareful not to shorten the needle or you would be purchasing another. Better yet later on we just switched out the fuel nipple spray bar with Super Tiger, they had a nice L shaped needle an fine threads with the longer needle point.

On RC motors they have greatly improved since the 70's. those things leaked an slopped fuel an ran erratic at times. But if you changed it out for Perry or sealed up the intake you had a much improved engine. Don't take me wrong here I prefer Fox over all else, but I never thought to much about the flat base they came up with on the intake front rotor. I had a friend which had a small machine shop which made a part to allow you to run a Super Tiger, or Perry carb. I liked ST an Perry carbs in the 70's an 80's. Those were my only real gripes with Fox but were easy enough to improve.

All in all durability with solid performance at a better price I think Fox wins hands down.

earlwb

Actually that blade tip was great. It eliminated any potential false needle settings like you get with the pointed needles. At the time Fox came up with the blade was when some other brands had a lot of trouble with false needling or needle settings changing in flight. I do not remember ever having a problem with a blade tip needle when I was using them. It solved a problem at the time. it is actually a tapered needle, but the two untapered sides keep the needle centered while the other two tapered sides provide for the adjustment of the fuel flow. Thus the needle doesn't move around changing the fuel flow.

There is nothing wrong with the Fox MK-X carbs it was the people using them that had the problems.  
I remember helping guys out at the flying field. I would get their engine adjusted and have it all working great. They would fly the rest of the day just fine. Then the next day, there they would be with the engine all out of adjustment again. They just had to go and start twisting the needles like crazy.  No matter how many times I told them to not touch the low speed, they would go ahead and do it.  I think having the low speed out and exposed for easy reach was too much for some people to handle. They just had to mess with it after it was set.  If you had the carb adjusted well, you would fly for several months without ever needing to touch the high speed needle to tweak it. Mainly when there was the main seasonal change such as from summer to winter and from winter to summer. Usually spring and fall weren't too much of a issue.

GallopingGhostler

This info is good to know, 1_Pitts_Special_1 and earlwb. I've seen some of the negative comments in other forums toward Fox engines, but they didn't seem fair to the brand. Since my Pronto build will be down the road will give me time to break in the Fox .25RC at my leisure.

OS seemed to solve the low speed needle on their smaller engines, the OS Max10R/C baffle piston and OS Max10LA. There was no low speed needle. I gather that the OS engineers solved that with the carb design. The Max10R/C proves the lack of need with a really good idle.

Sport_Pilot

The only thing Ididn't line about the Fox CL needle is that it stuck out like a sore thumb on profile models and broke off. The flat needle worked great, it would allow dirt and congealed oil to pass through and not clog the needle, that was the main benifit of the design. The RC needles did leak fuel, but not air if you are using a pressurized tank, which I always did. But not nearly as much as you would think, especially after a season or two. The castor oil would seal up the threads a bit. The carb never runs eratic.

I also like the flat base mounted carb. Never a carb leak from this, and never a cracked carb case from an overtightened set screw or clinch bolt.

Sport_Pilot

I agree about the MK-X carbs. It was actually better than the Perry carbs many people replaced it with. You always had to adjust the low speed mixture ring on the Perry from hot to cool days, and they were touchy. I had a FOX Eagle I from Tower that would not run with the supplied Perry carb, but runs great with a MK-X from a Fox .50.

Jim Thomerson

Fox changed the flat needle to a standard pointed needle around 1990. The late John Lowery brought Betty Fox to St. Louis CL contests several times after Duke passed away. He told the story that he had shown Betty that most Fox engines at contests did not sport Fox NVAs. Replacement needles were a money making item. He convinced Betty to make the design change.

1 Pitts Special 1

Its easy to see how some people do have problems with engine setups. I found it to be common with novice to play with adjustments. There is alot to learn. I guess it comes from that push to get just a little more when it is not needed. I had Rossi .61 when I lived in Florida that after breakin, just a click or two either way and it was not satisfied. Temps are another important part of engine setups. On cold mornings, on the first flight of the day give it time. Be sure to check everything, castor will causes gumming. A problem I was not plagued with, i think it is more of a problem with weekend warriors. Fuel is another issue with novices and some experienced. Once going to help out with a new CL Ringmaster, beautifully built for a novice, but the fuel they came with was a little can of Cox Fuel. No breakin never run. Lucky I brought a few planes myself.

The instructions in the box are good to an extent, but leaves a lot in the unknown to be figured out. The beginner has no clue when its broke in or any idea about engine RPM. An how many times have you heard if its smoking it is rich enough. Make a turn and listen to it lean out with that high pitch. If RC goes completely to electric I am done. Electric is nice but I just cant see me going that way. F3 flying with electric is not for me. I love the smell of castor in the morning. I hope these little gems never are banned or no market for them.

Everyone has certain likes and dislike on engines, I just dont care for the flat base for the carbs on Fox's. I think it left a bad taste with me with all the problems we had with them in early years. NO product comes out perfect everytime and maybe our area got the ones just a little off in those days. I took the back of an OS Max after a huge crash in soft sand to flush it out. And to my suprise a large piece of the connecting rod was shaved off from machinging and got through quality checks and made it into production. The new one looked like it belonged to another engine. Which brings up another issue I wish they would continue to make parts for older engines. I have some nice Rossi, Super Tiger, Profi, an others that need parts from wear or broken. Now just a collection of metal parts.

maxtenet

Back to the original question.

Perhaps I'm stating the obvious, but since you are going to use the Fox anyway, break it in and compare the two with the props you intend to use. They are both good engines and you really can't go wrong with either one. Besides, after 45 years and 120 or so engines I can tell you that, within reason, every one is an individual and performance depends on many variables, i.e. break-in tuning, fuel, etc.


Max[8D]