ptgarcia

My Feedback: (36)

I'm thinking about buying a Magnum XL 61 RFS 4-stroke for my Model Tech 40-size P-51. Does anyone have any experience with this engine? How does it compare to the Saito 72? I know the Saito has a larger displacement but is the power output of the Magnum close? I don't want to spend $200+ on the Saito when I can get the Magnum for under $140 unless the Saito has a lot more power.

Reported Tach readings for Saito 72:

15% Omega and 13x6 Master Airscrew - 9800 rpm

10% Cool Power and 13x6 Master Airscrew - 10,000 rpm

I'd like to hear what you guys think. Thanks.

w8ye

My Feedback: (16)

The Magnum 61 and the Saito 72 are one porop size apart. The Magnum 61 will turn a 12-6 at about the same rpm that a Saito 72 will turn a 13-6

Jim

ptgarcia

My Feedback: (36)

w8ye,

In your experience will the 61 and 52 about one prop size apart also?

w8ye

My Feedback: (16)

Yes, the 52 runs a 11-6 and turns the same rpm.

Jim

gregusan

My Feedback: (2)

How does the Magnum 61 XLS RFS compare to the Saito 56?

It seems they are about the same wieght, but I'm wondering if the Magnum might have more power due to the extra displacement.

Anyone know of a comparision, or have any numbers for both engines?

Thanks, [email protected]

old propnut

I have just installed a magnum 61 4st. in a Sig Rascal , Have about 4 tanks of fuel through it and 2 flights. Runs great ,just make sure you add 4 oz. caster to gal. of fuel for the break in, the Magnum really needs this for break in, you will not get good engine runs unless you do this.

gregusan

My Feedback: (2)

thanks for the tip on break in. Do you have any RPM figures for 12x6, 13x5, 13x6, or 14" prpps? If so, on what fuel, and what altitude are you at?

I still haven't found which is more powerful, the Saito 56 or Magnum 61.

w8ye

My Feedback: (16)

I have two Magnum 61's and they both turn a 12-6 APC at 9500 rpm on 10% fuel. My Saito 56 turns the same prop at 10,000 rpm with the same fuel.

Enjoy,

Jim

gregusan

My Feedback: (2)

Hi Jim: Thanks for the response! That's exactly the info I was looking for. I was assuming the 61 would be more powerfull, due to the displacment. I wonder how they would fair with a 13x6 or 14x4 or 5 on both? (I compared an OS26 Surpass to a Magnum 30, back to back, and found the OS more powerfull on a 10x4; 12,000 OS vs. 11,000 Magnum, but the Magnum wins on the 10x6; 10,000 vs. 9,800. However, the OS was "modded" a little).

When you flip them both over, does it feel like they have the same amount of compression? Maybe the Magnum has a lower compression ratio, perhaps it also has a thick head gasket.

It looks like the same design as an OS. I wonder if it can be "hopped up". I got 1000 extra RPM on 26 Surpass above with minor mods. Using a Dremal tool, I opened & smoothet the intake port to match the manifold. Stock, it was grossly misaligned, and mutch smaller than the manifold hole, so created a bottleneck at the head. Then, I drilled the exhaust outlet out.
This really "woke it up", and it still starts, handles, idles, and transitions fine.

I think the Magnum must be hiding some performance, since it's bigger but runs slower than the smaller motors in it's class. Hopfully it's also possible to put a thinner head gasket.

Well, this is only for those who don't mind a little tinkering and performance modding an engine, and have some basic understanding & experience of what makes any engine run better.

Maybe I'll try this on a Magnum some day, an post the results.
Has anyone else posted engine mods on here?

gregusan

My Feedback: (2)

Jim: Ps.. Just found this post from someone else who had his Mag 61 for sale. Could it be your tach is different than this guys? Wonder what the 1000 RPM difference on the same 12x6 apc could be caused by.

"This one has seen less than a gallon of fuel and in near mint condition. As with all my ringed engines, it was broken-in first with 5% nitro 20% castor the first couple of tanks, followed by 5% nitro 10/10 castor/synthetic for the remainder of break-in. All fuels are Ritch's Brew custom blends. It swings an APC 12x6 at 10,500+RPM on the bench, probably more but I've never tweaked the high speed needle to peak. "

http://www.rcuniverse.com/showthread...ight=magnum+61]

Rodney

We have many of the Magnum 4 strokes in our club and all have given excellent performance. In all cases they seem to compare favorably with the OS's, Webra's etc. at about 2/3 the price. Longivity and reliability has been great on all of them.

BackAfter20

My Feedback: (5)

My Magnum .61 RPMs are the same as Jim's. I'm getting between 9500 and 9800 RPM (depending on the day) with an APC 12x6 using 10% Omega.

w8ye

My Feedback: (16)

My two Magnums are exactly the same in what they turn. I only have one Saito 56. It's been two or three years since I was around anyone else's to tach it. There are a lot of 56's around here, I just havn't been at the field the same day they were.

Jim