Magnum XL .30 RFS 4-Stroke

Product Reviews · 12 of 12 known posts recovered

Hofacker · Jun 02, 2003 01:12 PM

http://www.retail-leaders.com/reviews/210935man.htm

Chris Chianelli reviewed the engine in MAN. See the above link.

I'm not seeing this level of performance. With about 1 hour of break-in time on the engine I'm seeing about 11.5K RPM with a 9-5 Zinger prop, and 9.1K RPM on a 10-5 Zinger prop. Max. These values vary plus and minus 100 or more RPM while the engine is running. The engine is VERY hard to start, and VERY sensitive to needle valve setting.

I'm going to fabricate a venturi repalcement for the R/C carb (that's why I was hoping to find some information on the proper choke area for 4-Stroke engines in the main forum) and continue the break-in process to see if things will improve.

So far I'm not impressed.

I'll keep y'all posted...

Hofacker · Jun 04, 2003 07:25 AM

#1 source

...anothe quart of fuel and no noticable improvements. I'm still using the R/C carb (for now).

I found some "info" on the Saito FA-30 for comparison. This is an apples to oranges comparison due to the many uncontrolled variables (a 10 x 4 Master Airscrew in not the same load as a Zinger 10 x 4, etc., etc.) but it may give a "gut feel" for comparison.

http://www.rcuniverse.com/rcarchive/209/2002/11/1/76766

FA-30 (10% nitro fuel, 17% all synthetic oil):
10 x 4 Master Airscrew black glass prop - 10,800 rpm...
11 x 5 Zinger wood - 8200 rpm and running very hot...
11 x 4 Zinger wood prop - 9500 rpm

One of the authors in this thread commented on the use of an OS type F plug... Question for the experts out there: what is your experience with different plugs? Hype or fact?

from these reports I'd guess that the Saito can turn a 1" greater pitch or diameter prop than my Magnum and appears to have a wider usable power band (i.e. could actually use a larger prop at lower rpm...). This is from very limited experience and your milage may vary...

...the learning process continues...

godzilla · Jun 11, 2003 12:22 PM

#4 source

>One of the authors in this thread commented on the use of an
>OS type F plug... Question for the experts out there: what
>is your experience with different plugs? Hype or fact?

There is no replacement for the OS Max F plug except for two EXACT copies. One is the Sonictronic F plug and the other is the YS plug sold by Central Hobbies (they say it is made in Japan by OS Max and they just put YS on it instead of F).

They other two plugs are cheaper, but frankly, I change mine about once a year so cost is not a factor...

Feel free to experiment, but chances are you will waste more mobey in the long run over just buying the Os plug...

The City Smasher

Hofacker · Jun 05, 2003 07:16 AM

#2 source

I've now fabricated a needle valve/venturi to replace the R/C carb and run another quart of 10% fuel through the engine. The home made NVA is pretty crude but works better than the R/C carb it replaced: the engine runs are much steadier without the large variations in RPM I was seeing previously.

I'm now able to get 11.6k RPM with a Zinger 9-5 prop and 10.2k RPM with a Zinger 10-4 (yes, 10-4 not the 10-5 I tried earlier) prop. The RPM is up by about 100. The engine still runs very hot with the 10" prop and the RPM "sags". More break in time seems necessary.

I'm still not ecstatic about the performance, but things are looking up. At this point I'd compare it to a decent .19. Right now I don't think it has the "grunt" to pull a smaller stunter designed for a Fox 35. I had hoped to put it in some thing like a "Ruffy". It might do OK in a "Tomahawk" or a "Super Clown". The ARF Flight Streak might also work... If performance continues to improve with break in time (and more nitro...) the Ruffy may not be out of the question.

...comments from the experts would be welcome...

LNeumann · Jun 05, 2003 07:58 AM

#3 source

I am ceretainly not an "expert" in much of anything, and have never run a 4-stroke in my life, much less the engine you have been testing (That's what this forum is all about--getting facts.) However, comments people have made about the larger Magnum 4-strokes in comparison to a Saito and others of similar size were that the Magnum 4-stroke seems to be an older design and certainly not the equal power-wise for displacement or in power-to-weight comparisons. The ones that seem to be the best are the Saito, the YS, and the OS Surpass, and for power-to-weight the Saito seems to be the winner overall and the (at this moment) engine of choice for those who have compared.

That could always change with new engine designs, so keep us posted.

Leonard Neumann

V12 · Aug 20, 2003 07:59 AM

#11 source

Len - you bring up a good point. When we started experimenting with the Magnum 4S a few years back, we contacted someone at the importer. We were seeking information regarding our disappointment with the power output. The fellow told us that the Magnum 4S line was basically similar in power to the older, pre-Surpass line from OS. This made sense in that we did try some of the older OS 4S and found that they were smooth, quiet and reliable but lacking in power. One fellow from our club tried the larger Magnum, a .52 I beleive and was also displeased. Other than the somewhat difficult starting, the Magnum 4S line should be very nice RC sport engines.
For a turnkey 4S setup, I'm still convinced that SAITO has the most to offer. ENYA must not be discounted but I wish they would offer a smaller 4S. OS Surpass, of course, is right up there. I've never tried a YS so I cannot comment on them.
For what it's worth. Bob Z

Hofacker · Jun 24, 2003 09:36 AM

#5 source

A little more "messing about" with my Magnum XL .30RFS.

In the process of fabricating a new venturi I removed the carburetor assembly from the cylinder head. I noticed that the port for the fuel/air mixture into the cylinder head didn't line up with the passage in the carburetor assembly and was quite a bit smaller in diameter than the ID of the carb assembly. I guess I'll ream this out to match. It can't hurt...

So far my opinion is, "spend the extra $30 and get a Saito...".

Does anybody know if the mounting hole spacings for the Saito are the same as for the Magnum?

Designman@Home · Jun 30, 2003 03:25 PM

#6 source

The Magnum will fly a Flite Streak on 55ft lines, but the Saito will do it on 60's.

I own both engines, and bought the Saito after comparing my Magnum on the same fuel and same prop back and forth with Ray Firkin's Saito.

There was a 400 rpm difference. And the Saito is marginally lighter.

Definitely worth, the extra, though at this point I'd get the Saito 40!

Larry

Hofacker · Aug 12, 2003 09:32 AM

#7 source

>The Magnum will fly a Flite Streak on 55ft lines, but the
>Saito will do it on 60's.
>
>I own both engines, and bought the Saito after comparing my
>Magnum on the same fuel and same prop back and forth with
>Ray Firkin's Saito.
>
>There was a 400 rpm difference. And the Saito is marginally
>lighter.
>
>Definitely worth, the extra, though at this point I'd get
>the Saito 40!
>
>Larry

Yeah, the Magnun was a real dissapointment for me. Especially after reading the glowing review in MAN. I was hoping to find somethin I could use in some "classic" era planes that originally flew with a Fox .35

Ty Marcucci · Aug 13, 2003 02:45 PM

#8 source

Since MAN is a commercial publication and most if not all the engines reviewed in it advertise in the mag, I'd be, in fact I am suspicious of anything MAN says. Many plans for PA back in the 60's & 70's were shown with the Fox .35, when in fact very few of those planes ever flew with a Fox in them. Guess who was one of the biggest and oldest advertisers with MAN? Da Duke.

Alan Hahn · Aug 13, 2003 03:09 PM

#9 source

Well MAN isn't the only mag that does this. I was just reading the latest copy of RCM, and Clarence Lee tested the Saito 40. He gave it all of 30 minutes of break-in before going for broke, I understand these guys are busy, but they are writing articles which are read by a lot of people. He did give it a pretty good review, but I suspect that it needs a bit more running than that.

However he then turns around and publishes a comment from a reader who claims that the engine run is determined by the height of an remote needle! Clarence Lee has been around for ages, and I was amazed to see this comment with his tacit approval. As an aside, if what the reader was reporting was true, then there must be an airleak in that particular remote needle.

In general I like Clarence Lee's stuff--especially some of his early stuff.

Alan

V12 · Aug 18, 2003 03:35 PM

#10 source

A number of people who tried the Magnum .30 have been disappointed. With the stock carb or a venturi, it just doesn’t seem to make the power of the SAITO or small OS 4S. At one point, we compared it to my OS .26 Surpass and it was no contest – the OS ran away from it. Besides being down on power, we could get neither consistent runs nor easy starting. I should mention that all of the Magnums with which we had experience were very early versions - it's possible that the newer ones may have been improved but I can’t say.

I have well over 200 flights on my SAITO .30 in the Little Cherokee. It is one of the easiest starting and most consistent running engines I’ve ever owned - definitely one of my all time favorites. After around one hour of break-in, I adjusted the valves and have NEVER touched it since – not even a plug (I don’t even know what’s in it). It has been run only on 5% nitro, 22% (50/50) Powermaster fuel. It comfortably pulls a .35 sized plane and will do the pattern on less than 2 ounces of fuel. I bought a 2nd .30 and it flies my Brodak Nobler much better than did the Fox .35. This is not just my opinion – it is from people who judged and flew the Nobler, comparing both engines. And, the package is actually lighter.

I would not hesitate to use the .30 on any plane built for the Fox .29 or .35. In fact, my nearly finished Argus will carry a new .30.

If I seem to be excited about the .30 I am, but there is something else out there that looks to be the next step – the new SAITO .40. Every bit as much of a gem as the .30 but now you can step up a bit in (aircraft) size. Mine will go into a small Cardinal. The SAITO .40 is a bit lighter than the Surpass .40, but I cannot yet comment about the power comparison since mine is not fully broken in. It is much easier to start and a bit less thirsty than the OS – time will tell.

Bob Z