Konrad

Earlwb,

I have to ask, isn't mehanite iron just a trade name for very fine grained cast iron. I'm not aware that Fox hardened his mehanite piston. Also I thought the matching cylinders were a soft leaded steel (I don't know the spec). During the breaking process (if done correctly) the piston surface would work harden. Also the soft liner would conform to the piston. I have even seen some mildly abused Fox lapped P&Ls re heal if given another breaking cycle.

Now for the ringed engines Fox used (I think they still do) a high carbon steel that was then "nitrated" (heated in an ammonium atmosphere oven) to a hardness of 65Rc + Fox called this glass hard. This hard cylinder is what gives Fox its bad reputation of needing so long to break in. It also gives Fox such a long life! Now once this nitrated layer is worn through the cylinder wears very fast.

In smaller displacement engine the lapped iron P&L gives great performance at higher rpm (22k RPM for the Cox Conquest and Rossi 15) as there is no ring to overheat and start to float. I hope the Fox 15BB is still a lapped P&L.

Whatever P&L set up Fox uses we can all be thankful there haven't been any ABN types in the line up!



Konrad

hsukaria

Earlwb, maybe the ceramic coating on the cylinder might be done similar the Russian Norvel engines, done by the same people? I have a Norvel AX-40 and it runs really great. But I haven't run it for a long time to determine durability (I have had it for 3 years now and fly it part time).

Konrad

$50 USD is a great price for a Fitzpatrick! I wasn't aware that they made a diesel of the engine.

While the velocity stack might help control the mess from the revertionary pulse. I still like to use (find) crankshafts with an early closing to keep the crankcase pressure up at lower RPM. This helps a lot with lugging power and tractability (handling) of the engine at less than full power. I think the Picco Aero engines close around 48° ABDC

earlwb

Konrad you are correct, I think the mehanite is just a trade name for a super finely grained iron material.

The Fox 15 schnuerle appears to be a ringed piston engine design nowadays: http://www.foxmanufacturing.com/inde...oducts_id=1038
But that might be a misprint in their website though.
I'll have to remember to look the next time I dig out a Fox 15 engine at home.

Sport_Pilot

Yep!

http://meehanitemetal.com/

http://www.stlprecision.com/meehanite.html

hsukaria

Makes me want to dust off the old school books! However, I did not enjoy metallurgy in school, wasn't dynamic enough for me. It's good to know that somebody is doing a good job at it though.

Konrad

Now do we want to discuss my pet peeve [X(] [:@]? Electroless nickel verses true chrome plating as it pertains to our toy engines didn't think so !



Konrad

hsukaria

We've heard you say something about Nickel before. Must have been really traumatic.

Konrad

Yep, $10K or so and a decade of wondering why the engines couldn't develop their full potential (power and/or longevity).

I'm now off to the Fox site to see if the 15bb has been crippled with a ring.



Konrad

hsukaria

$10k!!??? What, you were running your own engine factory? You don't like ring engines either? What's left, ABC, but that is toxic to the environment as somebody mentioned above.

carddfann

I wonder if Fox really did recently change the 15bb to ringed. I doubt it. I think its a typo on their site. My 15BB is about 2 years old and it doesn't have a ring. Its one of my favorite engines.

Mr Cox

My latest .15BB is less than a year old, no ring in that one...

Konrad

Something like that. But as I have said in the past I'm a slow learner! I'm here so you don't need to "learn" the mistakes I have made. I hope this make your journey through this great hobby more enjoyable.

On the 15bb I can't even find the misprint or quote.

All the best,

Konrad

carddfann

I wouldn't be surprised if Fox gets their ceramic sleeves from Russia since that's where Norvel is or was. I don't know if they're still in business. I think Norvel was the first company to use ceramic cylinders and might be the only one other than Fox. I had a recent Fox catalog where they said a 25 ceramic was coming soon and another catalog that mentioned 46 ceramic (but the description still referred to ABC and I messaged Fox about that opps). I was at the big Toledo show 2 years ago when one of the Fox salesmen told me they are getting out of ABC because the chroming process is nasty. If they still sell any ABC's its because they are using up old parts inventory. The 46 ABC was discontinued because its ABC. Maybe they will come out with a ceramic version. My concern about ceramic is the cost competitiveness.

hsukaria

Regarding the ceramic coating, Sig used to sell Norvel AX-40 for around $100 until Norvel went out of business, so Sig dropped the price to $75 for the AME (ball-bearing, 2-needle carb) and $60 for the BigMig (bushing, 1-needle valve with air-bleed carb). Sig still is selling what is left in their inventory, around 40 units left. I like that engine a lot. It is strange looking, but runs great. I don't know how it compares to the Fox engine since I haven't bought any Fox's yet. The ceramic lining in the Norvel is interesting since it does not have a liner, the piston is right on the cylinder, makes it lighter and better cooling.

But as I said before, I can't tell how durable it will be since I have only had it for 3 seasons.

hsukaria

There is always rings and Nickel (don't tell that to Konrad), and whatever OS uses in their ABL engines. I don't mind ring engines for general use, they are cheaper to replace the ring.

Konrad

Rings are fine. Just on small bore engines the lapped P&L is better as the engine can run in the RPM band were it can generate power. Nickel is also fine as a substitute for a ring. It is cheaper to manufacture than a ring (less machining and part numbers to control). It also doesn't have the physical constraints of a ring (a ringless aluminum piston doesn't float off the cylinder nor does it develop the heat that a ring can at speeds). As a "Green" plating it is far better than the acid used in plating chrome. But up to now it hasn't been marketed as a green plating but rather as an "ABC type". As an ABC type nickel is a very poor substitute as it is much softer than chrome (it is not as dimensionally stable) and it doesn't micro crack like chrome to hold lubrication. Both the hardness and micro cracking allow the true ABC or AAC engine to perform at elevated power levels without galling the piston and maintaining the piston the cylinder seal. Electroless nickel is NOT suitable as a high performance plating in our toy engine's cylinder.

As with all engineering one need to look closely at the materials one uses and the desired out come. I happy to see that Fox has dipped their toe in the pool of ceramics. Knowing these limitation, I hope one is then willing to pay the premium for the next generation of plating, be it ceramics or some other real innovation. Not just some re marketing of ANB with a new trade name.




Konrad

hsukaria

Like I said, so far, I have been happy with the ceramic coating. It would be even better if Fox can do it without a liner and save weight and improve cooling. I will wait and see. Whenever they get an R/C engine with ceramic coating, I'm going to get one.

Konrad

Don't tell me what?
Yes, many manufactures in the past did not use inserted liner. The great Fox Hawk is one such engine.

Konrad

hsukaria

Nowadays, OS calls their coating ABL, Advanced Bimetallic Liner. Now is that also another name for nickel? Or is it some new proprietary setup?

Konrad

Sorry this is a Fox thread.
I have been repeatedly told not to stray off topic. But electroless nickel can be applied with various properties. For example a harder plating results in a poor bond with the parent material. These properties can be controlled by doping the plating solution and controlling the solutions temperature. So in the strictest of terms one is using a different alloy in striving for the desired property. Bi layered or multi layered coatings are a standard industry plating practices. What you quote is just a trade name nothing new.

Yes, I know the top layer is nickel and I suspect the bottom layers are also. I did a quick test of the coating using Atomic absorption spectroscopy (flame) and found it to be nickel. I did not bother with placing a cross sectioned liner in a SEM (Scanning Electronic Microscope) as I knew the "new" coating would not meet my performance expectation.

Now to try to pull this back to Fox, you will want to look real closely at a Fox for your next performance engine as they are trying to bring new coatings to market that benefit us the end user not just the manufacture or their investors.


Konrad

hsukaria

thanks, I'll keep my eyes open for the next Fox release.

Konrad

I need to make it clear that Fox really doesn't make "high performance" engines as defined in the warranty disclaimer of another engine brand (not that they define the term). They make good solid sport engines. While I think the plating used in the new 60 CL is great the engine itself is a little heavy for its power level. I will say I would take it over most other engines from over the pond. But there are locally grown engines that are better suited.

All the best,

Konrad

hsukaria

My problem with locally made engines is that they are very expensive. Now I know you get what you pay for, but I am just a regular guy flying pokey planes. I am not looking for whopping power either. That is why I think most people are buying the cheap Chinese engines, if they break, get another one. Like cell phones and TVs are throw-aways. If Fox can design and sell a cheap-er engine that doesn't try to be everything for everybody, but go mainstream, I bet they can sell good quantities. Of course, the cost of labor gets us everytime.

Konrad

Now when you move up give Jett engineering a good look. The up front price does not make it a good ditch digger but once you make your first flight with it you will think it was a great deal even at twice the sale price.

http://www.jettengineering.com/

Now for a sport engine I think the Fox is in the same class as most engines today. Again Fox is doing us a disfavor with that high "list" price on their web site. Give then a call to see what the real street price is. For a sport engine with auto mixture carb and ball bearings and long term support Fox is the way to go. The big asian gorilla does not support even the last model of engine. Once there is a model change you have an orphan. With the Fox it will be decades before your engine is obsolete, and then they offer a great buy back program. Take all this into account the next time some sales flier sings to you its Syrinx song.

All the best,

Konrad