MDS 48 any good?

Beyond shit.

Too many say it sucks for me to trust one. There are many engines out there with great reputations to take a chance on this one.

Consensu is if you replace the carb, run it in well and truly, its powerful and reliable.

The money you spend on the carb and fuel to get it there outweighs the extra cost of a better engine in the first place.

Don't touch it unless you like the challenges of life.

Good ones are good according to lots of people. Bad ones are totally useless. No one seems to know whether they have fixed the problems with them or not.

My experience with one was questionable. First, I ditched the "break-in" plug that comes with it to eliminate the headaches trying to keep the engine running - don;t need a bad tempered motor during break-in when you're trying to get the cylinder up to proper temp and cycle it. Then, after a few bench runs it started to behave at the top end, pulled hard, but the bottom end was perpetually fussy and the transition left a lot to be desired. I'm no guru but I have a reasonable idea how to set 2C carbs, and all my other 2c motors behave very nicely from top to bottom. After 45 minutes of bench running we mounted it in a Hangar 9 Advance 40 and flew it around. The top end power was good for sure, so from the experience to date the porting/metallurgy/whatever seemed to be well done, but even after many more flights the motor had a nasty tendency to quit at low throttle settings and just had an overall tempermantal feel to it below WFO. Not confidence inspiring in other words. I very much agree with the comments that suggest that replacing the carb with one that works would result in a strong running engine. So why bother? Why not buy a strong running angine with a good carb to begin with would be my question. Aftermarket or factory carbs are too expensive to justify replacing one on a new motor for sport use IMHO.

My expereences with a circa 1987 pre-North American import MDS .40 were similar - strong motor, well built (except for the crappy fasteners, typical Eastern Bloc in that regard) but sub-par in the carb department.

Mike Dennett MAAC 36930

A good economical alternative is the Evolution 46 at $89.99. Our experience with them has shown them only to be slightly less powerful than an OS 46 and just as reliable. Click below link for more details.

I read those reviews with a grain of salt. The OS 46 FX really comes alive if it has the right prop on it. For fun fly type flying, I like to turn 13k on the ground at a minimum. In the air, the only time full throttle is applied is during verticals and when acceleration is needed. My post reflects my personal experience, not published HP numbers.

The test I was referring to was done by a fellow modeler using off the shelf engines. Not a magazine advertisement.

Brian, What do you consider the right prop for the OS 46 FX to give you 13K?

Joe L.

I can get 13K with a Top Flight wood 11x4. I believe an APC 11x3 gives about the same results. Of course, the baffle is removed and this is a well broken in engine.

Another good OS prop combo that I currently use on my SIG Somethin' Extra with an OS 61 is an APC 12x4. That's in the 13k (a bit over actually) range and gives awesome performance. It yanks around the 6 lb plane vertically with authority out of a hover.

Over the years I have grown parial to OS because of their blend of power and reliability in their 2 stroke line. Overall I would say that the quality of engines by all manufacturers available today vastly exceeds that of a decade ago. Most any engine is reliable in the hands of an experienced modeler who has the fuel system setup right, the correct glow plug in it, the correct fuel, and of course the correct prop and needle settings.

What fuel are you running? With those props it should be turning a lot faster! The average FX will turn a 10X6 APC over 13k on 10% sport fuel. An

11X3 is a lot less load. Just for comparison, a GMS .47 turns an 11X6 slightly over 13k and turns a 10X6 at 15k.

Yeah, I'd say most any engine but not all. There are still stinkers here and there. Sometimes QC problems cause one modeller to love a brand but another to hate it. Sometimes certain motors are just sub-par no matter which example you try. I'm not sure I ever heard a good word about the Cox Dragonfly .049 or .074 for example, that's a dated example but there's others. Earlier OS clones or near-clones from the East were certainly in that category.

I fully agree that you can buy an OS 2C engine with faith, they certainly balance performance with user friendly bevaviour well, and the QC is top drawer. But there are other excellent motors out there too that give away nothing to OS. And, stinkers notwithstanding, I agree with your thoughts about setting up motors too.. man I've heard so many stories about bad this and that, from people who shouldn;t be allowed to touch a good glow engine.. ;-) On the small engine side I lost count of the people who were advised by the guy at the shop that 10% fuel is fine for .049's, or that overprop the motors ("she'll torque it!") - I remember a guy with a TD .049 on a pod on a 2 channel 6 foot glider - typical setup at one time, should climb fine. Flew like a dog, and he came to ask me what was wrong. Well, what's with the

7-4 prop? So-and-so said it'll pull better. Uh huh. What fuel are you using? Oh dear - here, try this.Gee, now it works! Some people seem to hang on to glow plugs like they are gold (well, they seem like gold, but..) and don't register in their ears/mind the rpm drop when they pull the power to the plug as a symptom.

Mike D