skrez

My Feedback: (15)

HI Guys,
Im just finishing my GP US 40 and have a engine question. I have an older OS engine ( hardly used) that has 45 F stamped on the side. I think it is a 45FSR engine that OS built in the 80`s? How does this engine compare to the OS 46fx and 46 sf as far as power?
Best Regards,
Frank

DarZeelon

Frank,


It will make similar power to the .46FX, with similar prop sizes.

But it will be a bit louder than the FX and would tend to prefer slightly smaller props than the SF.


It will last longer than the FX and its ABC version will last longer than the SF's ABN version.
Ringed versions of the FSR and the SF would last the same.


The FSR engines were the ones that gave OS its good reputation.

skrez

My Feedback: (15)

Thanks DarZeelon,
Maybe I`ll try a MAS 10-7 or 11-6?
Frank

NM2K

My Feedback: (14)

------------------


Actually, OS had a great reputation long before the FSR series of engines were developed in the seventies.

Their OS Max series engines were already winning converts in the early sixties. I was one of them. Older modelers might say that it began earlier than that.

OS's .15 R/C engine in the sixties had quite a few followers. Don't laugh. Lots of models were built in the sixties using a .15 for powering simple R/C models. Old magazines will show you quite a few of those types of models. Believe it or not, the original Falcon 56 was designed to fly on a .15 to .19 sized engine.

My first "big" engine was an OS Max .58 R/C that I bought in 1969. OS had already attained plug-n-play satisfaction levels in that it was extremely easy to set up right out of the box. A few tanks of fuel at a rich high speed setting and it was ready to go. This was a ringed engine.

DarZeelon

Frank,


I would suggest the same prop sizes from APC, Master Airscrew Scimitar (gray), or 10.5x6, 11.5x5 from Bolly (Clubman series).

The small, black MA props are not very effective, as far as thrust goes.

You can actually see the performance difference in flight.

Flyboy Dave

My Feedback: (21)

Those props will work perfectly on that engine. The .OS .45 will run right with any
modern day "sport" engine.

FBD.

jaka

Hi!
No Master Airplane prop will perform as good as a Bolly, RAM or APC prop.

Regards!
Jan K
Sweden

Flyboy Dave

My Feedback: (21)

That simply is not true, Jaka. Master Airscrew props perform just fine.

The only, only, only application where an APC will out perform a MAS is in
the pylon racing applications. And that is simply because the props are specialty
props for the .40 sized racing engines, offered with odd "in-between" sizes and
thick hubs that will withstand the RPM, and the fact that that MAS does not
offer racing props.

They do offer, however, a line of beautiful, inexpensive, and strong sport props.

You assumption that since APC props are great for the racing engines, that they
will out perform other props in the sport applications, which is not true. I have
tried the APC props on several of my planes....and their performance was not
as good as the Master Airscrews.

In fact, I tried them on a couple props jet planes I have where top speed was the
paramount performance category....

....and the APC's props were pathetic. []

Both planes now run Master Airscrew propellers. They turn higher RPM's, and are
faster. If the APC's were better, I would be running them.

FBD.

djlyon

Ill have to disagree with you on that one Dave clear across the board and I also have a lot of experience from pylon to pattern to 3D and lots of stuff in between. The only place APC suffers is spin up time because weight. Must be the air is different in San Bernardino than in Castaic.

Denis

Flyboy Dave

My Feedback: (21)

....all three using specialty props.

jaka

Hi Dave!
I'm not speeking of pylon racing props particularly when I say that APC props are better (more quiet, deliver higher flight performance)than Master A props.
It's my experience from 31 years flying pylon racing , scale, aircombat and sport airplanes that in fact APC props are better than MA props. And I think most people agree on this.
There are better props than APCs in certain applications too, but I have never ever seen or experienced a Ma prop that is best for certain airplane.
What size prop have you tried in your F-20 prop jet? Is it powered by a .60 or .40 engine?

Regards!
Jan K

speedster 1919

My Feedback: (3)

JAKA your the guy that over props too keep 2 cycles quieter and less wear with low RPM. I'm with Dave. MAS is a better price , tuffer , consistent looking thur all sizes. I have some APC and when you lay different sizes next to each other some look KNARLY . With the gray you can't see them spinning as well.

DarZeelon

From a thread where Frank inquired as to what he should expect from his OS.45FSR, it has become a prop-slinging contest...

Master Airscrew black (series II/III) props will spin a bit faster than APC props of the same sizes.

I have seen an MVVS Q-500 engine that spun an MA 10x6 prop at 16,200 RPM.
Exchanging to an APC 10x6 dropped the RPM to 12,700...

...Not because the APC makes that much more load, but because the 10% higher load of the APC was just enough to prevent this Quickie engine from getting on-the-pipe. I.e. the base-line RPM of the #3246 'Q' tuned silencer, even extended, is higher than this engine can spin this prop without it.

In flight, the reduced load on the prop would allow it to get into the tuned silencer effective RPM range, but then there is the danger of a lean-run, since the engine is peaked at that lower RPM... This isn't good.


Typically, an engine would spin an APC at about 4-500 RPM less than a same-size MA, but the APC is a much more efficient and effective prop and despite the lower RPM, flight performance is generally better.

Bolly (+.5" ) belies them both...

The bigger black MA props (four-stroke) are even less efficient than the series II/III AND they are spun more slowly than the same-size APC. I only use them when no Bollys (or APCs) are available...

piper_chuck

My Feedback: (12)

This is because it's impossible for anyone to suggest using a Master Airscrew prop without others going on about how much better APC props are. Is there really a performance difference? Maybe, maybe not. Will most people really be able to tell the difference? Probably not. In many cases, people's opinions about props are swayed by:
1) Wanting to believe a certain prop is better. "I paid more for it, so it must be better".
2) Getting higher RPMs and concluding a prop is "more efficient".
3) Hearing higher RPMs in flight and concluding that the plane is faster.

jaka

Hi!
No ! Piper Chuck.
I don't care what name the prop has as long as it works (best). I don't settle for second best when I fly my airplanes , I try and try untill I find the best working prop for that airplane.
I don't say that APC always is best...What I say is that Ma props are never better than APC.
It's very simple...just try it out your self and see what's best (quiest and best climbing and speed performance)

Regards!
Jan K

demonfrog

from what i've seen, the MA will survive more crashes. i haven't broken a prop yet

and thanks for asking about the .45 f i just bought one and you got my question answered