Some advice needed if you please.

I am building a Great Planes Goldberg Tiger 60 Sport (http://www3.towerhobbies.com/cgi-bin...?&I=LXYXF9&P=0) and wanted to know which powerplant is suggested. The recommended Engines are .45-.65 cu.in. (7.4-10.6cc) 2-stroke

What is the difference between:
* O.S. 65LA ABN (http://www3.towerhobbies.com/cgi-bin...?&I=LXPUE1&P=0)
* O.S. 61FX ABL (http://www3.towerhobbies.com/cgi-bin...?&I=LXBY46&P=0)

If anyone could explain what the LA and FX are about, I would be most appreciative.

Thanks in advance for the help.

I am mounting an OS 72 4 stroke on my Tiger 60.

I flew a 50 4 stroke on the smaller Tiger II and it was great.

Tom

The LA series engine uses Nickel in the cylinder sleeve The FX uses a Nickel alloy.
LA use bushings instead of ball bearings,opposite for the FX it uses ball bearings.

Either of these are great for your plane and are really good engines. A lot of people like to over power things but either one of these O.S. engines u listed will have more then an ample amount of power.

That being said a lot of other brand engines do not quite have the "ummph" that O.S. seems to have so maybe if you choose others u may think about the .75 range.
Bigger engines usually mean lead in the A** so I tend to stay close to whats recommended.

Could be wrong but I think the FX uses ball bearings and not roller bearings.

Both engines will fly your Tiger 60 very well even off a grass runway. The 65LA will do it for less money (about $60 less)! The LA series uses an air bleed carb (one needle for adjustment) and is very user friendly but will not work in an inverted instalation. Tiger 60 mounts upright so it's good for this airplane. The FX series engines uses a two needle (idle and high speed adjustments) and is also very user friendly and will work inverted but that is not needed in this airplane. The FX makes more power than the LA but again it's not needed in this airplane as the LA has plenty of omph for the Tiger 60. If your a newbee or on a budget get the LA. If your OK with a two needle carb or not on a tight budget get the FX as it can be reused down the road in a wider variety of planes. Both engines are winners!!!

Thanks so much for the input.

I would like to re-use the engine at some point, so I would rather outlay a little extra now than have to buy a whole new engine later on down the road.
I am leaning a lot now towards the FX.

I am a newbie and this will be my second plane after a Great Planes PT-40.

Go with the FX. While the LA is a good engine and you would do fine with it, I think the FX is going to be a little easier for somebody just into the hobby. The LA's have the air bleed low end adjustment, and it's a fine art being able to tune one. I had just one engine with this on it and I won't have another. It's definitely a learned skill to tune the low end on one. The needle valve low end adjustment on the FX is a lot easier to adjust and isn't as frustrating for beginners

Hope this helps

Ken</p>

I flew the Tiger 60 as my second plane for about two years. I started out with an OS 61 FX. It was a great engine with lots of power. I bought it at an estate sale and it really needed bearings, so after a few months of flying it that way, I swapped it out with a Super Tigre 75 and a tuned pipe. WOW was all I could say for that combination.

My instructor said that I could use that plane for entry level Pattern competition, so I started practicing the Sportsman level routines and really learned how to fly really well with that plane. It was instrumental in my really learning to land the plane correctly, a technique I use all the time with all of my planes.

Either way, your engine choices are fine.. but I tend to shy away from the LA series engines for all the reasons mentioned above. And, I had great luck with the OS 61 FX as well as the Super Tigre 75.

By the way, as far as I know, that plane still flys today, even after all the abuse I gave it as a second plane.

CGr.

The FX is a far superior engine in many and more subtle ways than what has already been mentioned.

For one it is a very desirable engine and tends to retain its value for resale and retains your desire to want to use it in another airplane down the line. While the LA's any of them tend to get pitched in a drawer down the line. There are plenty of other brand "DRAWER" engines also and they do as advertised but they are just among the first into the drawer

The FX has far more aggressive port timing and venturi throat sizes which of course produces much more power but also in concert with the superb OS double needle carbs contributes to one of those more intangibles: Throttling or throttle response and this is a major but subtle factor with any engine.

If you can afford the more expensive engine then the answer to whether or not should you get it is a no brainer: You bet your Bippy

John

The magnum. 61 is always an option

The Super Tigre .75 is one of my favorite engines. When it is right it is a real treat. I have one on my GP Big Stik .60 turning a 14x4W, and another in a Phoenix Strega turning a 10x10.

I know odd props for those planes and this engine but they fill the purpose for me very nicely. The big stick is slow but a monster ( 20mph winds are best ) and will nearly 3D on high rates and hovering with this combo is easy.

The strega is insanely difficult to fly full throttle ( for me at least..... dual rates were a blessing...*note to self* faster means less throw) and landing takes a bit of work.... but if you like fast.......

I do not know all of the numbers like a lot of you guys do, but I can tell you that power is power and fast is fast, and when they are tuned right the ST are nice engines.

Says WHO?????

Mine work just fine thank you....

Failure to work inverted is more of an operator, tuning, or plumbing problem than anything else.

That said the FX is a better choice as you've indicated due to the better power output.

The .65LA is about the equivalent of a normally aspirated .46AX in terms of power.

If OPJOSE has a secret for making an OS LA series engine work well inverted, please share it with us. I tried for some time to fly one (46 LA) in a Sig Rascal 40 and could never overcome the dead stick problum. I replaced fuel lines, tanks,etc., tried another new 46 LA, tuned on it till I was as blue in the face as the engines were. The only thing that helped was the addition of an in line pressure check valve between the muffler and the tank. It didn't cure the dead sticks but it did help. I am not one to give up quickly on a problum, but I finely gave up and installed an OS 46 FX. That fixed it!!! I currently have 5 aircraft with inverted engines ( 2 OS FX's, 1 Saito, 1 MDS,and 1 V-Max) and they all do fine inverted. I also currently have 6 aircraft with OS LA's in them (5 mounted upright and 1 laid over 90* with a pitts muffler) and they all do fine also. MY EXPERIENCE has been that LA's don't work well inverted and thus advised aginst this apparent newbee using a LA inverted. If your experience is different please give us details on what LA engine in what aircraft worked well inverted and what you had to do to make it work. Also what has been the experience of other flyers out there who have tried LA's upside down??? I don't claim to know it all, just tried to give trouble free advice to Brad.

The Goldberg Tiger 60 often comes out a bit tail heavy as it has a longer-than-normal fuselage for a sport plane. Picking an engine on the heavy side will usually benefit the Tiger 60.

An engine like the .65 LA has several benefits. The air bleed carburetor is less sensitive than a twin needle type and rarely requires retuning. The plain bearing design isn't subject to problems with rust; the engine won't require after-run oil and would be a great choice if the plain will be flown on floats in the future. The primary downside of this kind of design is that plain bearing engines are more sensitive to lubrication types used in the fuel mixture. They generally don't run as well on synthetic lubrication and will produce more power, run cooler, and run more smoothly when significant amounts of castor oil is used in the fuel mixture.

An engine like the .61 FX also has several benefits. Dual ball bearings make the engine more flexible with regard to fuel blends; synthetic lubricants generally won't degrade the performance or longevity of a ball bearing engine. A twin needle carburetor can be easier to fine tune than an air bleed carburetor.

The notion that engines with twin needle carburetors and dual ball bearings are always better or more powerful than engines with air bleed carburetors and/or plain bearings is simply not true. Every cheap Chinese engine of dubious quality is twin needle and dual ball bearing (Aviastar, GMS, Evolution, etc.), while only the finest engine manufacturers offer models with plain bearings and/or air bleed carburetors (O.S. Max, Thunder Tiger, Enya, K&B).

To be more specific, the .61 FX doesn't outperform the .65 LA; the .65 LA will out-turn the .61 FX on a number of different props using the same fuel and glow plug. The plastic backplate used to lighten the O.S. Max LA series engines lowers their maximum compression and contributes to their reputation for weak performance. The .61 FX is an older design, and isn't a particularly strong performer with the stock muffler, either.

At the end of the day, your Tiger .60 will benefit most from the .61 FX for two reasons:

1) The .61 FX weighs significantly more than the .65 LA, and will help balance the Tiger .60 better

2) Fuel with 50% or more castor oil lubrication is very hard to come by these days. You'll most likely be flying with fuel that's 80% or more synthetic oil for lubrication

If an O.S. Max 2-stroke of .61 ~ .65 displacement is the limit of your shopping choices, then buy the .61 FX. If spending the extra money to go from the .65 LA to the .61 FX makes sense to you, spending a few extra dollars to jump from the .61 FX to the .75 AX is also a no-brainer due to greater performance and resale value.

You would also find the Super Tigre .61 ringed or .61 ABC, the Super Tigre .75 ringed, the Thunder Tiger Pro .61, or the Magnum XLS .61 to be very good matches for the Tiger .60 airframe. They may not offer the resale value of the O.S. Max .61 FX, but they offer better performance for $70 to $90 less.

Good luck and good shopping!

Thanks once again to everyone for their input and advice. There are so many options and so many variables that it hurts my brain.

So, to throw a wrench in the works in this whole post, I was at the field last night and there is a member who has a Tiger 60 ARF that he flies. I am building the kit, but no difference other than that. He has a 91 4 stroke in his and he has recommended I get a 91 size engine for the plane. I have ready to always stay on the high side of engine ranges recommended for the planes, but not to go over as this stresses the airframe.

So, now I am even more confused about what engine to get. I was pretty set on the FX, but what about the much bigger engine now? What is the safe assumption when the manufacturer recommends an engine?

A 4-stroke fires every other cycle and develops less hp than a 2-stroke of same displacement. From a practical standpoint a 91 4-stroke provides similar hp to a 61 2-stroke. "Magnum" is a brand name for Global Hobby and is used for a number of imported products that I personally have found good service with. The Magnum XL 91 RFS has been a very nice 4-stroke engine and works well in 60 size models for me (so far). A good 10%-15% nitro fuel with 18%-20% oil with some castor can be had quite readily by using a standard off the self fuel and adding a little castor oil to it. You can get the oil from your LHS, pharmacy, lab supply, soap maker supply, etc. Makes it easy, inexpensive, and you know for certain you have castor in your fuel blend.

The qualities that make castor a superior lubricant also make it a messier lube when its time to wipe off the plane.

Since you've no brand loyalty established yet why not check around your LHS's to see what various 60-75 2-strokes or 91 4-strokes are in stock. They may very well have one gathering dust because its no longer the "hot potato" in your area and may just make it worth your while. Unless you think you are going to want to sell it soon don't concern yourself too much with resale value.

My 2 cents,

Clay

Heres another spanner in the works......

A 60 size plane makes a pretty good home for a 15cc gasoline engine..

Theres are two currently available, JBA 15 and the RCGF 15.

No more castor to wipe off
Although many hobbyists promote castor as the holy grail of lubricants in reality there are far better synthetics for the purposes of lubricating a glow engine these days. PEople tend to cling to old habits in this hobby...
Most fuel manufacturers offer a Methanol fuel with synthetic lube and its good enough. Castor makes the engine sound smoother but thats means nothing when its gumming everything up inside and making a royal mess over the plane.

Consider Gasoline also

If I had the choice between 2stroke .61 and a .91 4 stroke, I would base my decision around airframe considerations and propellor requirements for the airframe and then consider the engine.

Wasted power often results in high fuel consumption and poor thrust. Determining engine characterisitics for a plane without  any consideration to the typ of flying the pilot wants toengage in is a shot in the dark at best.

Consider these:

Flying style:
Sport , Then 2 stroke .60 LA or .80 to 0.91 4Stroke is sufficient running mid range prop ( the if the recommendation is for 12x6-8, 13x6-8, 14 4-6, then 13x5 is fine
Aerobatic, then .75  to 1.00 ballbearing engine running a larer low pitch prop like the 14x4/5

Also bear in mind that if you opt for 4stroke you need to pay attention to vibration damping and reinforcing the entire airframe, this adds weight

Castor oil may not be the "holy grail" of lubricants, but you'd be best advised to not run a plain bearing engine like the O.S. Max .65 LA without it. The thick viscocity of the castor oil helps the crank shaft "float" inside of the engine bushing.

TimBle's recommendation of 15cc gasser is an interesting one. The normal drawback of using a gasoline engine on a .60-size plane is the added weight, but as I mentioned previously, this may be a benefit on the Tiger 60 airframe. The nose arrangement on the front of the Tiger's fuselage could make installing most small gas engines problematic, so you should investigate things like mounting width and exhaust options carefully before jumping into a gas engine.

As for the .91 4-stroke option, it's well worth considering if _brad_ wants to try his first 4-stroke engine. The Magnum XL .91 FSR and Thunder Tiger F-91s four strokes are about the same price as the O.S. Max .61 FX he was considering, so it wouldn't even be a more expensive option.

A .91 4-stroke engine typically weighs about the same as a typical .61 2-stroke. Propping the four stroke may be more challenging, as a typical sport prop would be a 12x6 on the .61 2-stroke but a 14x6 on the .91 4-stroke. The tricycle landing gear on the Tiger 60 may make a longer prop impractical due to ground clearance. You can always put bigger wheels on the Tiger .60 and/or build it as a tail dragger. You could also use a 3-blade prop on the 4-stroke to shorten the diameter by an inch (13x6 3 blade is roughly equal to a 14x6 2 blade prop).

There are a lot of terrific choices out there for powering a Tiger 60. As I said before, good luck and good shopping!

Just as you think you start to get to know a little about what is out there, the theory goes right out the window.

After speaking to the guy at the field with the Tiger and after reading all these posts, I sent an e-mail to our club president and asked for his opinion as he knows the fellow with the Tiger and knows a great deal about this hobby. He said to me that unless I want to do wild aerobatics and vertical climbs right after take off, then the .61FX will be a good choice the for Tiger and ample power.

So, having said all of this, I am not in the phase of doing any wild aerobatics. I would like to learn some aerobatics with the Tiger, but I am still learning being the most important point. This is only my second plane and my first low wing.

Thanks to all that have responded. I have learned a great deal about engines - so much so that my head hurts - and keep it coming. This is a fantastic way to learn.