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Nov 05, 2019, 05:35 PM
A man with too many toys
Thread OP
Discussion

Piston/Cylinder Durability vs Technology


For a sport flyer like me I have often wondered what technology results in the most number of flights. I do a lot of part power flying in a wide range of temperature conditions. Run 10 or 15% fuel with castor/synthetic mix of various brands.

I know that ABC is best for max performance - I just want to know what the average sport flyer should look for when buying a new or used engine.

1. Lapped Piston like most of the old engines had.
2. Ringed piston. Not really sure what cylinder material that nost manufacturers use.
3. ABN like OS and others use to save money.
4. ACB with real chrome plating.

Are there any other technologies that I have overlooked?

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Nov 05, 2019, 06:17 PM
AMA 46133
SeismicCWave's Avatar
Quote:
Originally Posted by RC Man
For a sport flyer like me I have often wondered what technology results in the most number of flights. I do a lot of part power flying in a wide range of temperature conditions. Run 10 or 15% fuel with castor/synthetic mix of various brands.

I know that ABC is best for max performance - I just want to know what the average sport flyer should look for when buying a new or used engine.

1. Lapped Piston like most of the old engines had.
2. Ringed piston. Not really sure what cylinder material that nost manufacturers use.
3. ABN like OS and others use to save money.
4. ACB with real chrome plating.

Are there any other technologies that I have overlooked?

.
Norvel or NV engines has some ceramic coating on the cylinder sleeve.
Nov 05, 2019, 06:40 PM
Registered User
For the sport flyer, I have seen and experienced that a ringed engine, not the Dyke ring (althu nothing wrong with it), will last for decades if run properly. Easy to start in all climates and easy to replace the ring, does not need a lot of carb tweaking and have a good amount of power for sport flying. Most can run 0-20% nitro. OS, Enya, Saito for 4C and so on have a good selection of all sizes.
Nov 05, 2019, 06:57 PM
Registered User

Engine Material


I would stay away from the Dykes Ring engines. I have found that they produce a groove at the top of the cylinder and this causes a reduction in power, probably about 10%. Two stroke cylinders are very expensive. Most of the older engines can be had real cheap now. I have several that are just like new.

Kip
Nov 05, 2019, 07:23 PM
A man with too many toys
Thread OP
I wonder why OS uses ABN instead of a ring. Maybe that would be better for sport flying.

Do all ringed engines just use a steel liner or do some brands use harder material?

I just picked up a Super Tigre .75 with a ring. Should have it in an airplane next string. Do the smaller ST engines have rings?

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Nov 05, 2019, 07:46 PM
Registered User
Quote:
Originally Posted by RC Man
I wonder why OS uses ABN instead of a ring. Maybe that would be better for sport flying.

Do all ringed engines just use a steel liner or do some brands use harder material?

I just picked up a Super Tigre .75 with a ring. Should have it in an airplane next string. Do the smaller ST engines have rings?

.
yes , I have a ringed 34 -51- 90 and a abc non- ring 45 .
Nov 05, 2019, 09:54 PM
Registered User
downunder's Avatar
Quote:
Originally Posted by RC Man
Are there any other technologies that I have overlooked?
A few.
1. AAC which uses an aluminium liner instead of brass and is considered to be superior to ABC.
2. Ringed with ABN liner such as some Enyas although their nickel plating is more like Nikasil, not just nickel like OS uses.
3. Ringed with chrome plated steel liner as with some earlier Super Tigres.
4. AAO which has an aluminium piston and liner but the liner is coated with an aluminium oxide as with the previously mentioned Norvels. This aluminum oxide has a hardness somewhere between that of hard chrome and diamond plating and, IMO, is about the ultimate. Trouble is that only the Russians so far have the technology to do this for commercial use.
Nov 06, 2019, 07:19 AM
Registered User
earlwb's Avatar
Quote:
Originally Posted by RC Man
I wonder why OS uses ABN instead of a ring. Maybe that would be better for sport flying.
Do all ringed engines just use a steel liner or do some brands use harder material?
.
For OS it was probably marketing, and lower costs. It reduces machining time and effort to use a ABN cylinder and ringless piston. By carefully timing the nickle plating process they don't have to machine or hone the cylinders like they do with chrome plating. But OS still makes ringed piston engines though, the helicopter engines come to mind first. Four stroke engines too.

Ringed engines usually use a steel liner. But chromed liners are used too (Saito comes to mind first), also Nikasil or a ceramic like coatings are used too. NIKASIL is used on most all of the larger gas engines, etc. The Ceramic coatings have to have some kind of a impurity added to allow the piston ring to wear in and seat good though. But if it is a ringless piston then it doesn't matter.

In my opinion the piston ringed engines tend to last and wear the longest for usage, as well as tolerate some abuse better too.
Nov 06, 2019, 08:44 AM
Registered User
I have always liked the fact that I can replace a ring in an engine that parts are hard to come by. That and some new bearings can keep an engine going for a long time. I do think that at some point this will become an issue with the demise of all the engine manufacturers. With that point being stated, I seem to have plenty of each type of engine.
Nov 06, 2019, 09:23 AM
Registered User
Cougar429's Avatar
Better materials can make a difference, but faulty manufacturing or QC can mitigate even that. Also, I found there are other factors that can determine engine life and quality. Good break in technique, proper operation and after run treatment can go a long way to maximizing performance and reliability/durability. Mistreatment can pretty much wreck even the best designed and built engine.

I had good luck with Fox engines in that the hardened steel sleeve often outlived 3 ring replacements. Only had to mod the head button to accept higher nitro content and try to fit larger mufflers to moderate the exhaust level.

I did have the chrome come off one Saito 100, but suspect that was initiated from the previous owner ignoring failing bearings.
Nov 06, 2019, 10:33 AM
A man with too many toys
Thread OP
My longest running engine is an old Veco 61. This was made after K&B purchased them. I think it was the last production run that said VECO and came with a nice but noisy muffler. I don't remember when I purchased it bit I did purchase it new - probably in the 70's. It was originally on a Kwik Fly III. It's been on several airplanes and I still fly it. Starts very easily with good power.

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Nov 06, 2019, 11:52 AM
AMA 46133
SeismicCWave's Avatar
>>For OS it was probably marketing, and lower costs. It reduces machining time and effort to use a ABN cylinder and ringless piston. By carefully timing the nickle plating process they don't have to machine or hone the cylinders like they do with chrome plating.<<

I wonder how much of that can be attributed to the low "break-in" time required with an OS ABN engine. Most OS engine instruction manual recommend the user to run a tank and just fly the engine to break in.
Nov 06, 2019, 11:54 AM
Registered User
surfer_kris's Avatar
Quote:
Originally Posted by RC Man
Are there any other technologies that I have overlooked?
The K&B sport series used a chrome coated aluminium piston that runs in a hard aluminium alloy cylinder (no liner needed).
Nov 06, 2019, 12:05 PM
A man with too many toys
Thread OP
Quote:
Originally Posted by SeismicCWave
>>For OS it was probably marketing, and lower costs. It reduces machining time and effort to use a ABN cylinder and ringless piston. By carefully timing the nickle plating process they don't have to machine or hone the cylinders like they do with chrome plating.<<

I wonder how much of that can be attributed to the low "break-in" time required with an OS ABN engine. Most OS engine instruction manual recommend the user to run a tank and just fly the engine to break in.
I know quite a few that buy a new OS, set the needle, and go fly with no break-in. OS probably realizes that and makes engines that will run that way.


Longest break-in I had was a Veco 45. This was when they first came out in the 60's - one of my first RC engines. That thing took forever - if it was not set rich on takeoff it would quit after a couple of minutes.

.
Nov 06, 2019, 12:13 PM
supreme being of leisure
ZAGNUT's Avatar
the AAO is just hard anodizing, nothing too difficult about it, easier to do than real chrome...harder to do than the electroless nickel of ABN engines. there used to be replacement piston/sleeve sets for OS that were the same. also used a lot in industry and in applications like aluminium brake calipers...almost always as a cheap and less durable alternative to hard chrome.

an awesome coating would be CrN which is a cousin to TiN but uses chrome instead of titanium in the process. very common on cutting tools and as a protective surface for plastic injection molds. harder than hard chrome, cannot flake off, and like electroless nickel does not need any honing/grinding after the "plating" process. only problem is that it normally requires high temps during application. there was a company a few years back that developed a lower temp method suitable for aluminum...don't know what became of them though.


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