News:


  • May 20, 2024, 12:41:53 PM

Login with username, password and session length

« previous next »
Pages: [1]   Go Down

Author Topic: Ring x ABC engines  (Read 2641 times)

Online Martin Quartim

  • 22 supporter
  • Trade Count: (0)
  • Captain
  • *
  • Posts: 802
    • StuntHobby
Ring x ABC engines
« on: November 23, 2009, 07:20:33 PM »

Today a friend ask me which engine is best to get an OS 46SF ABC or a Ring one and not knowing the right answer I like to hear your opinion about it.

My friend noted that some of the high performance R/C engines are Ring ones, like most Heli Engines, OS 160FX and OS 140RX.

So why one would want  ring engine instead of an ABC engine and vice verse?

Martin


Logged
Old Enya's never die, they just run stronger!

https://www.youtube.com/user/martinSOLO

Alan Hahn

  • Guest
  • Trade Count: (0)
Re: Ring x ABC engines
« Reply #1 on: November 23, 2009, 08:00:22 PM »
Perhaps one reason is that if the motor gets a little hotter than normal (like in heli use), the ring will continue to seal, while the ABC will lose power. I've had this happen a few times with a 1/2a engine and once you lose power, it doesn't come back during the flight.

Of course you wouldn't want to abuse that feature, because overheating isn't good for the engine in the long run. However if the engine sags in a maneuver, a chopper may go down hard, which isn't good for the chopper.

Another detail is that a ringed engine is easier to start if it is still warm, while sometimes the ABC can be a bear to get the tighter seal, if it is still warm. Although I have had reasonable success with ABC restarts.
Logged

Online Brett Buck

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 13754
Re: Ring x ABC engines
« Reply #2 on: November 23, 2009, 09:55:00 PM »
Quote from: Martin Quartim on November 23, 2009, 07:20:33 PM
Today a friend ask me which engine is best to get an OS 46SF ABC or a Ring one and not knowing the right answer I like to hear your opinion about it.

My friend noted that some of the high performance R/C engines are Ring ones, like most Heli Engines, OS 160FX and OS 140RX.

So why one would want  ring engine instead of an ABC engine and vice verse?

   With due respect to Alan, I think ABC or AAC is the way to go. The starting problem is a function of the technique. What happens when it's hot is that you choke it, cold fuel gets on the back of the piston, it shrinks, and the compression goes away. So don't choke it, or choke it just enough to get fuel to the venturi, and not up in the engine to any significant degree. With the PA, we usually get great and immediate starts with no choking if you do it quick enough. If you wait a little too long after the flight, *one* pull through will usually do it. On the RO-Jett, it takes 2 pull-throughs hot, then backflip and it goes right off. If you get "shrinky piston syndrome" in either case, just take off the battery, and flip it through a bunch of times (10-12) and that will even the temperatures out and the compression will come back and not feel "dead" any more. ABC/AAC was originally used (and still are) for racing where the hot restarts are critical.

     The issue I have with ringed engines is that they are so variable from day to day and week to week. Get a good one, it's great most of the time, and sometimes, it isn't. It easier to replace when it wears out, but it wears out much more quickly than ABC/AAC, then you replace it and maybe it works and maybe it doesn't. Some ringed arrangements are better than others but if I still had to used ringed engines I would probably have quit a long time ago. I would even take a iron-slug piston over a ringed engine at this point.

   The availability of ABC/AAC stunt motors was a huge breakthrough.  I really wouldn't be able to recommend any ringed engine if an equivalent version with any other construction was available.

    Brett
Logged

Offline proparc

  • 2015
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2391
Re: Ring x ABC engines
« Reply #3 on: November 23, 2009, 10:44:04 PM »
I am going to weigh on this one because it is something I have given a lot of thought to. Of, course, its all about quality. A good AAC\ABC will beat a crap ring motor and vice versa etc. I prefer ring motors a lot.  I REALLY LIKE my Saito's!! That said, For 2 stroke, it's more about what Randy does than the piston type!! My guess is that if he made a diesel it would probably take care of serious business!

Supposedly, RC helicopter engines are designed to be hyper reliable because of their operating environment. They run in a very high torque-high heat environment, and engine failures tend to be catastrophic for helis. The OS Max heli motors are VERY high quality engines indeed. Quite possibly the highest quality engines OS makes.

Starting is all about the motors, fuel, tanks, plugs, starting battery.
Logged
Milton "Proparc" Graham

Offline RandySmith

  • Administrator
  • Trade Count: (0)
  • Admiral
  • *****
  • Posts: 13747
  • Welcome to the Stunt Hanger.
    • Aero Products
Re: Ring x ABC engines
« Reply #4 on: November 24, 2009, 08:49:14 AM »
Quote from: Martin Quartim on November 23, 2009, 07:20:33 PM
Today a friend ask me which engine is best to get an OS 46SF ABC or a Ring one and not knowing the right answer I like to hear your opinion about it.

My friend noted that some of the high performance R/C engines are Ring ones, like most Heli Engines, OS 160FX and OS 140RX.

So why one would want  ring engine instead of an ABC engine and vice verse?

Martin




Hi Martin

It isn't even close, the AAC ABC will beat the ring in power and longevity  all day long, many times going 3 to 4 times the life of a ringed motor is very common.
Unless your in a really high heat scenario ,If I had a choice it would be one of the AAC over any ring setup.
Remember any high heat setup that would affect and AAC setup will also be very detrimental on a ringed one too, and you can loose a good ring seal with ..1... very hot run. the AAC setups are much much tougher and bounce back in these condition, but most times a ring never will.

Randy
Logged

Alan Hahn

  • Guest
  • Trade Count: (0)
Re: Ring x ABC engines
« Reply #5 on: November 24, 2009, 10:25:56 AM »
I don't disagree with you all, but was trying to come up with the rationale for Martin's question. His observation is true. I always thought it was a little puzzling that an OS32 for planes was ABC(N) while their heli version was ringed.

Also I think the AAC doesn't have the ABC feature that the brass sleeve expands more than the aluminum piston. Could be wrong about that altho' I thought that the matching expansion was one of the positives of the AAC setup.
Logged

Offline Jim Kraft

  • 2015
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 3412
  • AMA78415
Re: Ring x ABC engines
« Reply #6 on: November 24, 2009, 10:44:46 AM »
I would agree with what other have said. "But", I have three Anderson Spitfires, one lapped, and two ringed ones. All three are in practically new condition, but are broken in. The two ringed engines have way more power than the lapped one, and I have heard this from others also. The lapped engine does shake a bit more than the ringed ones because of the iron verses aluminum, but I still do not think that explains it all. Otherwise the engines are identical. Not sure how ABC or AAC would work in a gasoline burning sparker as they do run pretty warm.
Logged
Jim Kraft

Dave Adamisin

  • Guest
  • Trade Count: (0)
Re: Ring x ABC engines
« Reply #7 on: November 24, 2009, 02:31:12 PM »
The word I have on the subject vs a vs choppers is the high heat isn't the issue. It's the range of heat from long idles to full power that do in the ABC from a response point of view. The ring engines come out of long idle more reliably, so I'm told. Personally, give me a hard crome liner and a cast iron ring, but then again I actually like to work on engines........
Logged

Offline RandySmith

  • Administrator
  • Trade Count: (0)
  • Admiral
  • *****
  • Posts: 13747
  • Welcome to the Stunt Hanger.
    • Aero Products
Re: Ring x ABC engines
« Reply #8 on: November 24, 2009, 03:50:51 PM »
True Chrome plating is very very reliable in Heli s  I have made many chrome engines for people flying helicopters, The super thin (way way thinner than chrome) nickle that OS used was very unreliable and peeled very easy at high heat or anything that put a lot of pressure on the motor.
Chrome doesn't do that.
  I have seen many many motors with nickle that would wear all the way to the brass in just a 100 flights or so.

Randy
Logged

Offline proparc

  • 2015
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2391
Re: Ring x ABC engines
« Reply #9 on: November 24, 2009, 06:10:22 PM »
Quote from: Dave Adamisin on November 24, 2009, 02:31:12 PM
The word I have on the subject vs a vs choppers is the high heat isn't the issue. It's the range of heat from long idles to full power ........

That's it right there Dennis!!
Logged
Milton "Proparc" Graham

Online Brett Buck

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 13754
Re: Ring x ABC engines
« Reply #10 on: November 24, 2009, 11:04:47 PM »
Quote from: proparc on November 23, 2009, 10:44:04 PM
I prefer ring motors a lot.  I REALLY LIKE my Saito's!!

   Of course, in this case, you need the blow-by to lubricate the bottom end - so if you like 4-strokes a true ABC/AAC is not an option.

     Brett
Logged

Online Brett Buck

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 13754
Re: Ring x ABC engines
« Reply #11 on: November 24, 2009, 11:24:30 PM »
Quote from: RandySmith on November 24, 2009, 03:50:51 PM
True Chrome plating is very very reliable in Heli s  I have made many chrome engines for people flying helicopters, The super thin (way way thinner than chrome) nickle that OS used was very unreliable and peeled very easy at high heat or anything that put a lot of pressure on the motor.
Chrome doesn't do that.
  I have seen many many motors with nickle that would wear all the way to the brass in just a 100 flights or so.

Randy

       This is one of those things that delves in to the area of "holy wars" but I would note that both Paul Walker and I ran individual 40VFs for something like 2000-3000 flights over a period of about 10 years before we wore them out. If I had a choice I would certainly pick an AAC (and did) but I haven't had any problems with the ABN in a a reasonably controlled situations. Of course I ran my PA for 6 hard years, even running grit through it on several occasions,  and didn't even bother carrying a spare. And it was still a very strong runner.

    But I said my piece above - I would take just about anything over a ringed engine just for the repeatability. Even my Foxes, with all it's other problems, were dead-nuts repeatable -  which is a lot more than I can say about any ST46 I ever had (and mine were more reliable than most).

    Brett
Logged

Offline proparc

  • 2015
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2391
Re: Ring x ABC engines
« Reply #12 on: November 25, 2009, 12:25:08 AM »
Quote from: Brett Buck on November 24, 2009, 11:24:30 PM

Even my Foxes, with all it's other problems, were dead-nuts repeatable -  which is a lot more than I can say about any ST46 I ever had (and mine were more reliable than most).
Brett

That is a HEAVY statement for sure!! :o
Logged
Milton "Proparc" Graham

Offline RandySmith

  • Administrator
  • Trade Count: (0)
  • Admiral
  • *****
  • Posts: 13747
  • Welcome to the Stunt Hanger.
    • Aero Products
Re: Ring x ABC engines
« Reply #13 on: November 25, 2009, 08:51:00 AM »
Quote from: Brett Buck on November 24, 2009, 11:24:30 PM
      This is one of those things that delves in to the area of "holy wars" but I would note that both Paul Walker and I ran individual 40VFs for something like 2000-3000 flights over a period of about 10 years before we wore them out. If I had a choice I would certainly pick an AAC (and did) but I haven't had any problems with the ABN in a a reasonably controlled situations. Of course I ran my PA for 6 hard years, even running grit through it on several occasions,  and didn't even bother carrying a spare. And it was still a very strong runner.

    But I said my piece above - I would take just about anything over a ringed engine just for the repeatability. Even my Foxes, with all it's other problems, were dead-nuts repeatable -  which is a lot more than I can say about any ST46 I ever had (and mine were more reliable than most).

    Brett


Brett

Please re read my post.
When you ran the OS, you used fuel with more oil than the typical RC fuel, also you needle setting wasn't as lean as many Heli and RC flyers use. So you were ..not.. putting as much pressure on the liner as they do, This is the situations I was talking about, not, people like you and Paul using them in a C/L situation.
If you reread my post you will see that I was talking about a hi heat scenario which is common in Helis and RC plane.
That said I have had several VF and FP  C/L engines in here to replace liners and pistons that where worn thru to the brass. And many others that were peeled badly with not many flights on the engines.
Dave Shadel made a living replacing thin nickle liners in R/C engines
In any case chrome will be much better in any wear situation than the much thinner electrolys nickle coating could ever be.

Randy
« Last Edit: November 25, 2009, 12:40:33 PM by RandySmith »
Logged

Offline Steve Fitton

  • 24 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2272
Re: Ring x ABC engines
« Reply #14 on: November 25, 2009, 09:09:47 AM »
My AAC/ringed DS 60 has been good.  714 flights so far with absolute reliability, and it swings the 12.5x5.2 3 blade Mejlik with ease.  The ring isn't a huge advantage on hot starts, you still have to learn a cold/hot start routine, but thats the case probably with any engine other than....electric.
Logged
Steve

Offline Jim Kraft

  • 2015
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 3412
  • AMA78415
Re: Ring x ABC engines
« Reply #15 on: December 17, 2009, 09:51:28 PM »
Back in my R/C pattern days, a friend of mine was flying YS 120 four strokes. He used to have that problem where the engine would run just great, and then two flights later it was a dog. He found when it was running good that the ring was positioned in a certain place. He wound up pinning the ring, and then it ran great all the time. I do not know if this would help engines like the Tigre 46.

Brett brought up something that I have wondered about also, as some of the Saito 4 strokes have used AAC, or ABC, with no ring. I figure they must use quite a bit of taper in the cyl. to get some blow by. Both of my OS 4 strokes have rings, and both of the Saitos I have are ringed also, one of them being a 90 twin. Any body have any thoughts on this?
Logged
Jim Kraft

Online Brett Buck

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 13754
Re: Ring x ABC engines
« Reply #16 on: December 17, 2009, 10:47:59 PM »
Quote from: Jim Kraft on December 17, 2009, 09:51:28 PM
Back in my R/C pattern days, a friend of mine was flying YS 120 four strokes. He used to have that problem where the engine would run just great, and then two flights later it was a dog. He found when it was running good that the ring was positioned in a certain place. He wound up pinning the ring, and then it ran great all the time. I do not know if this would help engines like the Tigre 46.

     Possibly - but if you have a good ring the position of the gap doesn't seem to matter, and you can feel the compression forwards and backwards is about the same.  With a bad ring it has a lot more compression backwards than forwards when the gap is on the intake side, and more forwards than backwards with the gap on the exhaust side. Hard to say which way is actually better in flight. For whatever reason the bad rings always seemed to migrate so the gap was to the aft or intake side and tended to have more compression backwards than forwards when you flipped it on the ground. That was pretty consistent no matter which engine, at least for me. Of course there's no way to know which way it actually goes in flight.

   Note that the "goodness" of the ring seems only remotely related to the size of the end gap (at least the static, cold end gap). I have had good rings that had good compression and ran well with end gaps of as much as 4-5 thousandths and as little as <.001. I think the difference between "good" and "bad"  is almost entirely due to the materials.

    I said it over and over but I will repeat it again - the ring quality is absolutely everything on the ST, and if you have a good one it's not at all fussy about anything else.

     Brett
Logged

Offline Steve Helmick

  • AMA Member and supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 9950
Re: Ring x ABC engines
« Reply #17 on: December 19, 2009, 12:57:49 PM »
Quote from: Martin Quartim on November 23, 2009, 07:20:33 PM
Today a friend ask me which engine is best to get an OS 46SF ABC or a Ring one and not knowing the right answer I like to hear your opinion about it.

My friend noted that some of the high performance R/C engines are Ring ones, like most Heli Engines, OS 160FX and OS 140RX.

So why one would want  ring engine instead of an ABC engine and vice verse?

Martin

I would wonder if the cylinder timing would be the same for the ringed and ABN (or ABC?) versions of the .46SF. Possibly, the OS factory provided an option for somewhat different uses.  I am sure that an ABN/AAC/ABC would produce more power than the equivalently timed ringed setup, because of less obstructed ports. 

There could possibly be some upper displacement limit on how well the ABN/AAC/ABC setups would work, but there are a few ABC .75's and .91's out there. The "size limit" could also be based on material costs for the high production engines, or the sizes in which the desired material is available without special ordering and higher costs.

I want to avoid ringed engines if at all possible. Almost all I have are fitted with Bowman rings, or will be, ASAP. ABN/AAC/ABC setups work wonderfully, last and last (even ABN!) and don't suddenly go haywire like ringed engines can.   y1 Steve


Logged
"The United States has become a place where professional athletes and entertainers are mistaken for people of importance." - Robert Heinlein

In 1944 18-20 year old's stormed beaches, and parachuted behind enemy lines to almost certain death.  In 2015 18-20 year old's need safe zones so people don't hurt their feelings.

Advertise Here
Pages: [1]   Go Up
« previous next »
Tags:
 


Advertise Here