Hey Guys n' Gals

Time to choose an engine. I understand the difference between 2-stroke and 4-Stroke and I know the engine is measured in CU , example .40 , .45, .46...

What I don't know is the difference between, LS , ABC BB , FSR , FS Non-Ringed and so on. I imagine each manifacture has its own sub-name(?) But I'm sure they all hold some sort of importance.. HELP!

Thanks guys.

Dennis

glow engines either have a ring around the piston or do not. the ones without a ring are labelled "ABC" or "ABN" (Aluminimum piston running in a Brass sleeve that is Chromed or Nickeled). Almost all of the modern engines are pretty good today, even the low cost ones like the OS LA series. Another cost factor is how many ball bearings are on the crankshaft. The lower cost engines have a brass bushing and the more expensive engines have two ball bearings to support the crank. Finally, the carburetors generally come with one needle valve and a air bleed (cheap) or two needle valves (more expensive).

I like the OS .46, the Thunder Tiger .46 Pro for beginners. The TT .46 pro is the best value, I believe.

I'm not an engine expert by any means but over time I have learnt a few of the series's. Eg in the O.S range the LA series is their cheaper non bal bearing engines while the FX series (also AX) is the more powerful ball bearing range. For Thundertiger their cheaper series is the GP range while the Pro is the ball bearing type.
With most manufactues if their engine name ends with a H eg OS50SX-H then it is a helicopter engine.
There are heaps of others but someone with more knowledge in this area ahould be able to help you out a bit more.

When I'm choosing a new engine, I tend to look at horsepower, weight, the reputation of the manufacturer and the model. In general, I ignore the marketing labels and just focus on the engine specs. Most of my engines have ball bearings (BB). Some are ABC, others are ringed. I have several OS FSR engines.

Edit: fixed typo

Hello Piper,
Well.. honestly you really didnt answer my question, you went on to post about all the different types of motors but you didnt tell me what they mean

I dont fully understand the different labels outside of BB and the CU..

Also the guy at the LHS said that the LS engine is something that he recommended for the trainers becuase it is a light weight engine with a smaller block, Does this make it less powerful then a normal engine in the same class?

Dennis R

The BB stands for Ball Bearing. Some of those suffixes tend to be manufacturer specific. For instance I have no idea what CU stands for. but LA is OS Max's suffix for a bushing motor, non ball bearing. The FX , such as a OS Max 46FX is a ball bearing motor. as is the AX made by OS Max. A bushing motor tends to have less overall hp. Its just my opinion but I believe it is because there is a greater friction or resistance to movement in a bushing motor than in a ball bearing motor. While the Bushing motors are lighter and less expensive, the ball bearing motors offer a better performance and higher top end(for the most part). Also the power curve, (the time it takes to obtain full hp versus the top hp) is steeper on a ball bearing than on a bushing,,,,resulting in a faster acceleration. Any one else wanna add onto this thread, let us know what some of the other mfgs suffixes stand for.

Sorry, the message I was trying to give is that many of the labels are just that, labels. They often vary by manufacturer. You can usually find information about every engine from usually major manufacturer on the web. The Engine product guide here in RCU is also a good source of information. I looked around some, but could not find an engine with an LS designation, but I found that many car manufacturers use LS. Who's the manufacturer? Perhaps you meant the Magnum XLS engine?

Power and weight are independent. Some engines are light and powerful, some are heavy and powerful, some are light and not so powerful, and others are heavy and not so powerful. It's all up to how the engine was designed, and is often related to cost. Lighter weight and higher power engines typically cost more.

Since weight has an effect on flight quality, one would think the lighter the better. For the most part, this is true. However, if the designer messed up and made a part too light, and not strong enough, then the part may fail. This is why I suggest looking at the reputation of the manufacturer and also of the particular engine.

Personally, I don't think light weight and a smaller block are reasons to select a particular engine for a trainer. I would think the selection criteria would be ease of use, reliability, and decent power. As a beginner you want an engine that is easy to start, has good idle and midrange speeds, needle settings that are not overly sensitive, and that is durable enough to handle the inevitable mishaps. You need to spend your time at the field flying, not tinkering with the engine settings. An engine that's easy to adjust will allow you to fly while you develop the skills to tune the engine properly.

Another important thing to keep in mind is whether the engine has the right power range to be used in subsequent planes. For example, many of the trainers say they will take .40 to .45 engines. Some people might go out and choose a decent .40 engine for this trainer. That's an ok choice, for the trainer, but when they move to their next .40 size plane they will discover that this engine may be marginal. If instead they had chosen a .45 or .46, they would have an engine with more power, but only a little heavier, and which could handle a much wider range of planes and flying styles.

FSR is a label for Schnuerle porting. If I'm remembering correctly, on OS engines this label meant Front Schnuerle Ringed. I've read the details on exactly what this does long ago, but unfortunately those details have moved to the part of my brain where all other information that's not really needed goes.

There are lots of good sources of info on the web. MECOA, a company that bought ownership of many different brands of engines, has a pretty good FAQ. It's here: http://www.mecoa.com/faq/index.htm. Among other things are descriptions of Schnuerle porting, ABC versus ringed. Someone in the extreme speed prop plane forum recently referenced a prop speed chart in the following online book: http://www.bolly.com.au/book/. I've looked at it a little and it seems to have lots of useful information.

So, back to the LS engine. I don't know the person who recommended it to you. I assume it's the guy you mentioned in another thread who offered to teach you. He's either a straight up kind of guy who is steering you in the right direction, or someone trying to unload some inventory. In this hobby you'll find both kinds. I'd like to think he's looking out for you, but a bit of verification, that you're obviously doing is never a bad thing. Look up the specs on the web. How do the weight and horsepower compare to other engines with similar displacements and prices? Look at the RCU product guide to see if anyone has rated it. Do some searches to see if people have posted their experiences, good or bad. If it looks like a good choice, go for it. If not, choose something else. The nice thing about this hobby, is there are many choices, and often many of them are the "right" choice.

Piper Chuck has this one put to bed (good answer Chuck). The thing you need to realize is that model companys do the same as auto companys. They have thier LS's and SSR's and a whole host of jargon. You really don't need to know any of that. You need to know only a few. BB usually refers to ball bearing supported crank shafts. These engines are preffered. They usually have more power and are more reliable and longer lasting.

ABC is the other. ABC (or ABN) referres to the construction of the engine. The aluminum piston rides in a brass cylinder that is chromium (or in the case of n nickle) lining. They do this so that the piston to cylinder fit will be perfect when the engine is at operating temprature. Ringed engines are just like thier automotive counterparts. They use a piston ring (sometimes called a Dykes ring after the inventor) to make the seal at operating temprature. ABC engines are easier to break in and are generally easier to use for a beginner. Ringed engines are fine but take more to break in. You chould look at an ABC engine for your first one.

Most everything else you can disregard. I would not reccomend the OS LA series engines. Many like them, I do not. I have read so many threads and reports that were unfavourable to make me want to stay away from them. They do not have as much power as similar engines that cost the same.

Having said that. Here are some engines that I would suggest. I suggest a 45 or a 46 as they will be of use to you later on. I see no use for the 40's. The extra pwer will come in handy. Anyway the OS 46 AX, Enya 45, irvine 45, Thunder tiger 46 pro, and super tiger GS45 are all proven easy to use engines. The Thunder Tiger has a very devout following and is probably the best value of them.

One last thing I would point out. You are doing the right thing. Coming here and asking questions. If you have more try using the search function. It is right at the bottom of the page. Type in your questions and brows the answers. There is tons of info in here. Also check the engines forum. Lots of info there as well. Best of luck.

Mark Shuman

Thanks Chuck , Mark and Soonerace

All this information is VERY informative and exactly what I needed!

So lets see, I got Trainers , Kits and Engines down.. Hopefully my next questions will be a little more technical.

Dennis

The guy that gave me this information seems to be very str8 up, he told me his hobby now is helping people learn how to fly and the main reason why he works at the LHS is because he meets people there, hes in his mid to late 50's earl 60's he seems like a very knowledgable guy who has been flying for 20 years. He mentioned balace played a key factor and witht eh LA engine the plane will be balanced just right, but I'm thinking I am going to get into a .46 BB of some sort.

Mark, one more thing. Tower Hobbies has a .46BB ABC engine (I feel like i know something now )

Have you heard anything about this particular engine? http://www2.towerhobbies.com/cgi-bin...?&I=LXJA86&P=0

I recently did a poll to see whether I should get that Tower Hobbies .46 ABC engine, or a similarly priced Super Tiger .51 ringed engine, the Super Tiger won hands down in the poll, but have a look at the thread and decide for yourself, a number of people did like the TH engine...

[link=http://www.rcuniverse.com/forum/Tower_%2546_ABC_Vs%25_Super_Tigre_%2551_Ringed%3F% 3F/m_2349311/tm.htm]TH .46 ABC vs. ST .51 Ringed Poll[/link]

Paul, that is a big engine though, I would have to get trainer that will take that.

Will you be able to squeeze a .51 CU engine into a plane that says .40-46?

Yup, a 50 will fit where a 40 will. A 50 is just a poked and stroked 40. Same outside dimensions. I do not like the TH hobbies engines for a beginner. They do have lots of power. But they can be cantankerous. They have quality control and air leak issues. I feel that they are just to finikey for a beginner. The other reason I don't care for them is they are a screamer. They make power at high rpm's. A beginner would be better served with one that does not operate that way. A lower rpm engine like the Super Tiger is a better choice. This is my opinion only. With some work and tinkering the TH engine can be made to run very well. I feel though you do not need this at the start.

Mark Shuman

The OS .50 and Super Tigre .51 will both fit in .40 sized trainers with no problems. The extra power is nice for when you need to get out of trouble fast, like aborting a landing at the last second. I got an OS .50 SX ringed engine for my Avistar, when I first started flying planes. I figured I spend the extra $$$ up front to get a good quality engine, and just re-use it in my subsequent planes. So far it's made it through two crashes (dug it out of the dirt on that last one) and is now flying my SPAD very reliably, and with plenty of power.

I highly recommend the OS .50 SX for someone starting out, but if you can't swing the $$$ for it, the ST .51 ringed engine is about half the price!

Personally, I think beginners should start out with an engine that matches the manufacturers specs. I've seen beginners learning really sloppy habits, such as 45 degree climbouts, when their planes were over powered. Trainers should be about learning to fly on the wing, not the prop. Higher power to weight ratios can come later.

You could also get the super tiger .45 at tower for $60. It is a nice engine, and easy to tune. It is also ABC, so it will break in faster than the ST .51 ringed engine, and has about the same power.

Dennis...Be carefull when you break-n an ABC engine as they have a tapered bore which does not expand until hot. Do not follow the directions provided with O.S. engines. Search "engine break-in" for info on how to treat these engines. Dar Zeelon and even Bill Baxter of O.S. will give the proper break-in for an ABC engine. Dave

Wow, this is awesome.

All of you have made good recomendations. I looked into the OS 50sx and was heavily thinking about it, seems like a good solid engine.. however I want to do this right and learn right, I don't want to pick up any bad habits.
I will probally choose between the Super tigre .51 and the TH ABC..

These are my main concerns:

1) Is the engine reliable, if i get into minor aerobatics and Roll, I don't want a staller..
2) Is the engine easy to tune. I live about 10mins from the LHS and could bring the engine if i have any tuning probs but I would rather do it on my own.. So i would like an engine that isnt that finicky.
3) Longevity... I suppose if you treat any engine the right way it can last forever though..right??
5) I don't want to out grow my engine in a few months.


Dennis R

This issue relates more to getting the tank at the right height, and making sure the exhaust pressure works, etc than to the engine.
The reports from people in RCU will give you one source for identifying engines that are not finicky. The people at the field are another. However, it's important to understand the difference between a finicky engine and a person who can't tune right. Over time you'll probably notice that certain people are always "messin wit their engines". Others just show up and fly. You also should rely on help from your instructor. Early in your training he should teach you how to tune the engine.
Unfortunately, not entirely. Parts do wear out. Quality control problems slip into production runs. Manufacturers go cheap when they order parts such as bearings. New, and unproven, designs end up being bad ideas. However, in general, if you stick with the well known brands and treat your engine right, it will last a long time. I still fly the OS 25 FSR that I had in my second plane, sometime in the late 70s.
You're looking at a good size range.

I would stay away from the TH 46, it is a crapshoot with the engine. Also, for a newbie, the engine break in procedure is pretty complex. I had one it never worked right, tower sent me a replacement and it never worked right either. Since then I have had 2 TT pro 46. Super easy break in right out of the box its a super engine, never one deadstick in about 5 gallons of fuel between the two.

And by the way, it's CI, not CU. (Or Cu In)

It stands for Cubic Inches of displacement within the combustion chamber of the engine. Most of those you are talking about are 0.40, 0.46 or 0.50 CI.

Car engines were always described in cubic inches of displacement in the past; such as Chevy's 283, 350, 396 and 427, or Ford's 289, 352.... etc., etc. Today they tend to label in Litres, like 4.5L which translates into about 275 cu in.

When you get into larger gasoline powered RC airplane engines they'll be in CC's. Such as the Quadra 35, or Desert Aircraft 150. (35 cc's is about 2.1 CI, 150 cc's equals about 9.15 CI.)

Not nit picking, just thought you'd want to get your facts straight.

Good advice on engines so far, by the way.
Dennis-

Just some thoughts and random stuff to toss out:

- HP numbers, as reported by engine companeis is a totally useless number. They get the HP reading using a really small prop and cranking the engine to some serious RPM, much higher than you'd see in normal use. You really want to know the HP produced at the engine's peak torque RPM, but no one reports that. So, to know what engine is more powerful, you need to actually look at tach readings for the prop you want to use and compare that way.

- Due to differnet port timings and bore/stroke ratios, etc, some engines like to run at high rpms with small props, others like to turn slower with larger props. This means that the HP numbers might be totally misleading, since a trainer usually flys better on a slower turning, larger prop. An engine that is timed to scream on a small prop may not fly the trainer as well as one that produces more low end torque.

- The good news is that most of the common engines you see mentioned here are built for generally good running at moderate RPM, using fairly conservitive port timings and compression ratios to make the engine easy to tune and put out decent power in the process.

- Ringed engines, in theory, last longer than ABC engines. However, most engines are done in before they are just worn out, so really, life span is determined more by how often you fill the engine full of dirt than anything. Not all piston rings are Dykes rings, but many (most?) are. I have seen worn out engines though.

- On a ringed engine, you can replace just the ring. On ABC engines, the piston and liner are a matched set and have to be replaced together. It should come as no surprise that the piston/liner combo is the most expensive part in an ABC engine. So, if you eat dirt and kill your compression on an ABC engine, the repair is going to cost you. Ringed engines tolerate dusty envrionments better, and can sometimes survive eating stuff that would kill and ABC engine.

- On the flip side, as a ringed engine heats up, the ring expands, creating a better seal. If the engine overheats, the ring can seize in the liner. The result is a dead engine. I've seen ringed engines break conrods and crankshafts just because they were set a little lean and overheated. Since you also have to replace the piston and liner when that happens, you have an instant paperweight.

- As ABC engines heat up, the liner expands faster than the piston, so the hotter they get, the looser they are. So an ABC engine won't be harmed by over heating, it just looses compression and slows down. Note, however, that a lean run is the most common form of overheating. If you run lean, you can still damage the engine due to lack of lubrication. But the engine won't seize up like a ringed engine will. And if you over heat due to a bad cowl install, you probibly won't hurt the engine.

- ABC/ABN is just one kind of non-ringed engine. There are a few other types out there. Norvell, for example, makes some interesting non-ringed engines. However, ABC/ABN are the most common engines in the .40-size class. ABC Stands for Aluminum, Brass, Chrome. Al Piston in a Chromed Brass Liner. ABN is the same, but Nickle instead of Chrome. OS has something they call ABL. It's really another flavor of ABN, they just claim better Nickle alloys.

- BB engines are heavier, and as said, usually produce more power than bushed engines in the same size, but not always. Norvell, for example, makes some bushed engines in the .25 class that absolutly kick but and will out rev most BB engines and weigh a lot less. (but they have a reputation for being touchy.)

- FSR used to mean Shnerle (sp) ported. Most all .40 class engines are ported this way now. This porting is basically a way to get more fuel/air mixture in to the engine and get more power.

- .46 engines came about by taking .40 engines and boring them out. (In fact, some .40's can be converted to .46's by just replacing the pison, liner, and head. The case, crank, bearings, carb, etc are all the same). So they usually weigh less than a .40 and produce more power. Many .50 size engines are also bored/stroked .40's so they fit the same mounting dimenions. .40 size engines are slowly going the way of the Dodo, there is no reason to buy a .40 when a .46 is available for $5-$10 more from the same company.

- That said, a .40 as part of a combo deal that meets your budget isn't necessarily a bad idea. I have an OS .40 LA I run in a beater trainer. It's not as powerful as some engines, but with the baffle removed from the muffler and an APC 10x5 prop, it pulls the trainer around well enough.

I thought Ford's was a 351

If you are associated with a club or a group of fliers, take their advice and run the same brand of engines they do. They know those engines pretty well and can help you out better than if you show up with an engine they are not familiar with.

Jim

Thanks Kirk for going into extreme Detail on the engines, thats exactly what I needed.

After another 45min visit to the LHS I decided on what setup I was going to go with and what engine. The guy that has been running OS engines for years and will be flying will I will be flying, so he will help me out with any problems or questions I will have as he is very knowledgeable. I will be getting the OS .46 AX , he said that is will be just perfect and I won't really grow it out to soon. He runs on a FX and was telling me that the AX is basically a lille more beefed up and just as reliable as the FX. It is a little bit more then the TT and the TH engine but he said that the price outweighs the quality.

So far this is my setup.

Trainer for me: Carl Goldberg Eagle 2 ARF
Kit (for my dad to build) : Great Planes Piper J-3 Cub
Engine: OS .46 AX ABL
Radio: Futaba 4YF or 9C.


Dennis R


edit: If the futaba 9c Radio fits in my budget would you guys reccomend for me to jump right in, or should I first use an entry beginner radio like the 4YF. I don't want to jump in head over heels and out do myself.