Magnum XL RFS 91 Four Stroke

Magnum XL RFS 91 Four Stroke
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Magnum XL RFS 91 Four Stroke - 4/25/2008 10:06:05 AM

brrzee

Posts: 85
Joined: 4/24/2006
From: Selkirk, MB, CANADA
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Just wondering if anyone has had experience with this engine. I just purchased it from hobby people the other day. I am installing it in a SIG Skybolt biplane I am currently bringing back to life. Input or experiences would be appreciated

Thanks

Post #: 1

RE: Magnum XL RFS 91 Four Stroke - 4/25/2008 12:23:49 PM

w8ye

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Joined: 12/11/2001
From: Taylortown, OH, USA
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People are very well pleased with their Magnum 91 four strokes

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Post #: 2

RE: Magnum XL RFS 91 Four Stroke - 4/25/2008 1:30:52 PM

MOTORMAN37

Posts: 2044
Joined: 10/26/2002
From: CLINTONVILLE, WI, USA
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They run allmost identically to the OS .91 surpass.

http://www.rcuniverse.com/forum/m_2807824/tm.htm

< Message edited by MOTORMAN37 -- 4/25/2008 1:34:09 PM >

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Post #: 3

RE: Magnum XL RFS 91 Four Stroke - 4/25/2008 5:04:25 PM

Campgems

Posts: 1645
Joined: 2/18/2006
From: Arroyo Grande, CA, USA
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I've been flying one since Jan of last year in two different 4*60's, one of which is no longer with us. Close to seven gallons of fuel and it just getting time to check the valves. Nothing more than a click or two for major weather changes. Pull it out of the car, fuel it up and go fly. Just a great engine.

Just break them in per the instructions. Run them a tad rich. I run it about 500 rpm off peak. Three dead sticks in this time all in two days. I pulled the tank and replaced all tubing. Back in the air. No issues with the engine as long as you supply it with good fuel.

Don

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Post #: 4

RE: Magnum XL RFS 91 Four Stroke - 4/25/2008 7:27:45 PM

brrzee

Posts: 85
Joined: 4/24/2006
From: Selkirk, MB, CANADA
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Thanks for the input, looking forward to getting it installed and running. As well, what sort of glow plugs are you running?

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Post #: 5

RE: Magnum XL RFS 91 Four Stroke - 4/25/2008 7:35:30 PM

Campgems

Posts: 1645
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From: Arroyo Grande, CA, USA
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O.S F plugs are the only thing to run in four strokes. At least that is what I'm told and what I've used. Actually that isn't so. I tried a fox and another brand in an O.S. 52 surpass and finally settled on the O.S. F plugs.

I also use Omega 15% Fuel. I tried the Cool Power and wasn't happy with it. Expecially after it ate the pickup line on my filling pump.

Don

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Post #: 6

RE: Magnum XL RFS 91 Four Stroke - 4/25/2008 7:45:42 PM

brrzee

Posts: 85
Joined: 4/24/2006
From: Selkirk, MB, CANADA
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I heard that as well about people trying to only run an OS glow pug. Sorry for the all the questions, but what sort of engine mount is recommended as well?

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Post #: 7

RE: Magnum XL RFS 91 Four Stroke - 4/25/2008 9:11:29 PM

Campgems

Posts: 1645
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From: Arroyo Grande, CA, USA
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I highly recommend these

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXD630&P=SM

They take up a lot of shock of a prop strike and I fully believe that they have saved several of my engines as a result.

Just make sure when drilling for the engine, that you allow for the head of the socket head screw, lock washer, flat washer, and at least 1/8" to clear the carb. I screwed up my first by posistioning the engine to far back on the mount and when I screwed it to the firewall, I couldn't screw down the engine.

Don

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Post #: 8

RE: Magnum XL RFS 91 Four Stroke - 4/25/2008 9:21:36 PM

r2champion

Posts: 350
Joined: 9/5/2006
From: Mayking, KY, USA
Status: offline

I have about 6 flights on my Magnum 90 4-stroke since the breakin using 1 tank and couldn't be happier. It was also my first 4-stroke and I think I made a wise choice at that. It couldn't be easier to start and just purrs right along with plenty of power, idles extremely well. I am very satisfied with it. I also use the OS F plug.

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Post #: 9

RE: Magnum XL RFS 91 Four Stroke - 4/25/2008 9:27:17 PM

MOTORMAN37

Posts: 2044
Joined: 10/26/2002
From: CLINTONVILLE, WI, USA
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Any engine mount that is designed for a .91 fourstroke will work just fine. The Dubro mount is over kill and not needed for a .91.[)]

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Post #: 10

RE: Magnum XL RFS 91 Four Stroke - 4/25/2008 9:35:17 PM

Ed Cregger

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From: Ringgold, GA, USA
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I have used the Dubro iso-mounts with 1.40 and 1.60 sized gasoline engines, such as the RCS 1.40, MVVS 1.60 and the Evolution 26GT. Come to think of it, I've also used the same 1.20 size Dubro mount with a Poulan 46, BME 44 & .50 and a Super Tigre G2300 (1.40).

I see that the price has come down a tad. For a while, they were selling for $30 plus.

Ed Cregger

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Post #: 11

RE: Magnum XL RFS 91 Four Stroke - 4/25/2008 9:53:01 PM

asmund

Posts: 1826
Joined: 11/20/2005
From: Floroe, NORWAY
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I love mine to death, it is my most used engine and serves duty in my Katana profile and does tailtouches on a regular basis, GREAT engine!!!!!!

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Post #: 12

RE: Magnum XL RFS 91 Four Stroke - 4/25/2008 10:09:28 PM

Ed Cregger

Posts: 7496
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From: Ringgold, GA, USA
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Back on topic.

I love my Magnum engines too. For me, it is a tie between the Magnum .52 and .91 four-strokes. Both are sweet running, dependable engines.

Just follow the break-in instructions and be sure to use fuel with at least some castor oil in the lube mix.

Ed Cregger

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Post #: 13

RE: Magnum XL RFS 91 Four Stroke - 4/26/2008 12:51:02 AM

rlmcnii

Posts: 399
Joined: 7/3/2005
From: Pocomoke City, MD, USA
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Campgems,

I have been assisting an older fellow I know who is getting into RC. His entry plane is a Sig Kadet Sr. powered by a Magnum .46 two-stroke. It was my first, first-hand experience with any Magnum engine and it was a very pleasant introduction to these engines. We broke it in and got it tuned today. It runs very well.

Like any RC'er, this fellow is planning his next airplane and wants to go with something low-winged and a little more sporting. My suggestion to him was a 4* 60.

He also shows a bit of interest in a four-stroke engine and, because of his good experience with the .46, would be happy with another Magnum.

So, did you encounter any mounting or weight-and-balance problems with the .91 in your 4*? My thinking was that the .71 or.72 (whichever) may be a little low on power for this plane. I fly a Bruce Tharpe Venture 60 (fist cousin to the 4*) with a Saito .82. The .82 is fine but the plane could stand a bit more power. It flies very well but does not have unlimited vertical capability but then, neither do I!

This fellow probably will not want an over-powered plane, so if anyone has experience with a 4*60 with the smaller Magnum four-stroke, please don't hesitate to chime in. (Perhaps this thread will tolerate a wee touch of highjacking.)

Thanks in advance.

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Post #: 14

RE: Magnum XL RFS 91 Four Stroke - 4/26/2008 4:42:16 AM

Campgems

Posts: 1645
Joined: 2/18/2006
From: Arroyo Grande, CA, USA
Status: offline

quote:

ORIGINAL: rlmcnii

Campgems,

I have been assisting an older fellow I know who is getting into RC. His entry plane is a Sig Kadet Sr. powered by a Magnum .46 two-stroke. It was my first, first-hand experience with any Magnum engine and it was a very pleasant introduction to these engines. We broke it in and got it tuned today. It runs very well.

Like any RC'er, this fellow is planning his next airplane and wants to go with something low-winged and a little more sporting. My suggestion to