65 Chevy

My Feedback: (1)

Thanks Mick,
I wondered about the throttle response and power of the 61. Thats why I was thinking of the 12 X 4 APC. I do have the 12 x 5 APC also. so I will probably start there. I also have 2 Magnum 80's and an ASP 80 available, so if the 61 is short on power, I know I can go with the 80 instead. I was thinking about the 61 because of weight. I have the same plane here with an OS 50 SX and that has very good vertical and hovers and pulls out very well. The 61 4 stroke is only 1 1/2 ounces heavier than the 50 sx.

I appreciate the help and information

Bodge

Chevy,

That's the advantage of the 61 - it's fairly light. Once you start to go larger, with ASP/Magnum at least, you immediately jump up to 91 weight. With the 65, 70 and 80 weighing within 10 grams of the 91, you might as well use the 91 for everything...

If I remember correctly, I belive the 61 was pulling a 13 x 4 at 9,800 rpm on 5% fuel. Performance wise it is very similar to the 46 two strokes - and weighs about the same. It's a much nicer engine to fly with than the 46 and responds well to the throttle in a hover. I don't think it will have the performance of an OS 50, though. Certainly my ASP 52 2 stroke would leave it standing.

proptop

My Feedback: (8)

I've got a .28, a .52 and an FS1.20

Guys...I have an early-mid 80's TT .25 (never been run, so I couldn't tell ya if it's poop or not )
Would that be basically the same as a Magnum?

William Robison

My Feedback: (3)

[b]PT:

Go back to page one of this thread, I have posted two pictures of my TT made Magnum GP 25 there. If yours is the same, I suppose it could be called a "Mislabelled" Magnum. Haw.

Bill.

FrancisPerson

Is a Magnum .28 any good? What size prop will it turn? I want to put it on a 3 and 1/2 lb Junior Tiger.

Francis

What RPM numbers with what prop ?

William Robison

My Feedback: (3)

[b]Francis:

My little GP 25 runs about 13500 on the 8x4 three blade cut to 7" diameter. Hauls the Eaglet like there's no tomorrow. The Mag 28, being a newer design should be at least as good.

Bill.

William Robison

My Feedback: (3)

[b]Francis:

that dinn't sound right - rechecked (foul memory) and it's a 9x4 three blade cut to 8" diameter.

Bill.

FrancisPerson

Thanks, I had hoped to get a MECOA .32 as it is the same weight as a Magnum .28 but the MECOA .32 is no longer available.
The combat guys at my field like Magnums so I am inclined to try one.

Francis

lpg

Hi all

Does any one know if a muffler from an os .91 2c will fit a Magnum .91 2c. I am mounting this xls .91 inverted and looking for a muffler that will fit in the cowl with only os showing possibility's... and yes Magnums sometimes has problems... but nothing that can't be solved all the while, making you a "better" mechanic.....

Bodge

Yes: the magnum/ASP are designed around OS and pretty much all silencers are interchangeable, size for size. A few other bits too...

lpg

Thank you.

order is placed, Thanks again

LordSirOb

I tried my first 4 stroke, a Mag XL-70FS. So far, I am happy. 1 gallon of 10% omega for break-in with an APC 13 X 6 prop, with the last 1/2 gallon breakin in the air. The valves were adjusted and now I'm using Wildcat 15%. I had to lean in the low end just a smidgen to get a smooth transition, and peaked on the ground at 10K and I fly at 9.5K rpm.

I must say that purchasing another Magnum was a hugh leap of faith on my part after being the unfortunate owner of the XLS 52A POS. So far, this engine is performing very well. I may have to try another Magnum 4 stroke if this one keeps up.

Kimhoff

My Feedback: (22)

Well, I picked up a Magnum FS91 off of E*** for $80 complete with muffler and prop nuts. What a nice running engine. idles all day at 2200 and pulls my 60 size Stinger nicely.

Ernie Misner

Try a little 46 XLX when they go on sale for $49. I love mine!

Ernie

pbunn

My Feedback: (1)

I had an older Magum .46 ball bearing that was new in the box - but about 5 years old. My son had a Global trainer wing fold and it went in from 500 feet. Bent the crank. I emailed Magnum service (Global) and told them the sad story and that the wing folding had ruined the motor. Guess what? They sent a reconditioned - it looked brand new - .46 ball bearing model and it is a great little motor - a real screamer.

I have about 6 Magnum motors - three four strokes and three two strokes and I have had good luck with all of them. The .30 four stroke surprised me as I had heard lots of negatives on it. I have it in a Modeltech Cub and it is very strong and reliable running inverted.

Ed_Moorman

My Feedback: (1)

lpg,

The mufflers for the OS .91FX and the Magnum .91XLS will interchange. I had both engines, but dumped my older FX because it kept overheating.

If you really want some rpms, try an Ultra Thrust muffler or a Jett. I have a long chamber Ultra Thrust (designed for the 14-6 prop in the 12,000 range) on my Mag .91. Gained 1,000 rpm.

NM2K

My Feedback: (14)

Engines do not cause crashes, my friend, unprepared pilots do. This is not meant as a dig, but it is the truth.

Part of flight training should be teaching the student pilot how to react to a loss of power and to always be expecting a loss of power at any time, while constantly updating his/her options should a loss of power occur.

Nine times out of ten, flameouts are caused by taking off too lean, or fuel system problems. The engine has no reason to quit if all else is well.

I wrote this in hope that you would adjust your thinking of flying models. It is tempting to blame an engine for a crash, when it is really our lacking of a particular set of skills that causes the crash. No offense intended.

Ed Cregger

NM2K

My Feedback: (14)

Things have changed since then, Dave. But you do have to run some castor in these engines or they will die an early death.

Ed Cregger

PlaneKrazee

My Feedback: (14)

I don't own any Magnums, yet.

I have tried to tune several Magnum 4 strokes at the field. There seems to be a QC issue/wide tolerance range on these engines. Some run well, some don't. Case in point, a dc-3 with two magnum four strokes. One ran great, the other not so much. Could not get one of them to behave, not good on a twin.

Saito and OS aside from a known lemon or other constant problem are good.

I would like to try the 52 four stroke but the one I have seen run would not run well.

RC-Captain

I sure do appreciate your thoughts and definitely will not take offense to your opinions. The way I see it this is a forum and anything said is really an opinion until proved different. So heres my attempt to prove the difference between a WELL MADE ENGINE THAT DOESN'T LET YOU DOWN ON THE FIRST FLIGHTS and an engine that will almost always let you down on the first flights.

I own an AP.15 yellow Jacket, and OS .40,.46 FX, .25FX, and .70FSII, along with the magnum .25 POS I hate to even mention. Now I will let you and this entire forum pick from my list of engines the only one that I dead sticked with continuously with until I had to alter the engines low speed needle valve in order to get a descent flight.

Yes I crashed the plane , but just like with the other 5 engines I trusted the .25 magnum engine to at least fly the plane well enough to not advance me into a crash situation.

Thank for your comment, although I believe it doesn't fit my situation. Have you ever heard of the bad apple in the bunch ?

PS if you are wondering why I bought it, the answer is I was being cheap. [:@]

grumpE

My Feedback: (6)

I am a "member" of several clubs. Learned how to fly on an OS 40 LA, the definition of easy. Learned how to needle on an OS 40 FP and OS 46 FX. Learned how to replace bearings on an used Mag 61 Pro which flat screams. Got a very strong TT 40 Pro because it was only slighty more than an OS LA and learned about being open minded and what value means. Won an OS 46 AX and it is a joy.

Re-learned about bearings in used engines in an OS FS 90 (20 plus years old) as well as how to make gaskets etc.

Learned how to run fourstrokes with an OS 70 Surpass, used of course but a strong strong engine. Picked up an OS 70 Surpass II because I liked the Surpass so much and yes it is a VERY nice engine.

Fell for the very pretty Saito 91. What can I say. It runs strong, sounds good and to me "looks" like what and airplane engine should look like.

Re-learned about value with my Magnum 91 four banger which pulls nearly as hard as my very cool saito with barely any more need for tuning etc.

Just picked up a Magnum 120 4c for a Cap 232. I learn slow but two leasons in value seems to have been enough.

None of these engines are perfect. They all have quirks. But they all have benefits too. If I had all the disposable income I could wish for I would have a Packard Merlin if you know what I mean. As it is now I do not need the all out top fuel experience which is YS, I still drool for Saito engines. OS is one fine line of products and I harbor no ill will toward them. TT and Magnum are solid engines in my experiences both as an owner and watching fellow flyers at my field. The money saved per engine (OS 120 vs Mag 120 4c) will buy me a lot of fuel for next year.

Just my humble $0.02

Eric

JPMacG

My Feedback: (2)

I have to give Magnum high marks for their warranty. I sent in my 1 year old XLS46 because I was finally losing patience with it not shutting off (yes, I tried all the usual fixes). They sent me a brand new XLS46A very promptly with no question. I notice that the new one has a sealed front bearing while the old one did not. I'll find out how it runs this weekend.

jayd99

I was having a problem of my XLS46A running way too lean, but I finally now have it running perfectly. Of the several suggestions I tried, I think the one that made the most difference was to plug one half of the Magnum Pitts style muffler. I have the motor on a Global Decathlon 52 with cowl, and even with the high speed needle at 8 1/2 turns (and about to fall out), it still ran way too hot. I tried a cooler plug, cut bigger holes in the cowl, raised the tank, and messed with the low speed needle valve. Now with more back pressure, I get better fuel flow, a nice blue streak of smoke through the whole tank of fuel in the air, and the HSN is only about 2 turns. Now the exhaust oil is almost clear rather than charcoal black, and I'm not burning up glow plugs once a week.

The motor idles great and is very reliable. Fortunately there was no permanent damage, and it still has plenty of power.

Ernie Misner

Jayd, yours is a great testimony to the value of the true chrome bores in the magnum. With a lesser engine and nickel plating, the lean runs would have ruined it!

Ernie

NM2K

My Feedback: (14)

Chrome is certainly more durable, but nickel is okay too, if applied correctly and carefully. Thunder Tiger engines utilize nickel plating and they seem to hold up just fine, as do modern Webra engines.

When paying less for something than average, one cannot expect the same level of quality control. By buying such an engine, you have accepted the possibility that the engine may have wider varying tolerances than a more expensively made example of the same engine (OS).

If one is experienced enough at running engines, the less expensive engines can be quite a bargain. If you are new to operating glow engines, you might be better off in buying the more expensive engine for your first few models. After all, when beginning, accumulating lots of flight time without interruption is of key importance. During this period, you will gain sufficient experience operating glow engines to eventually handle the vagaries of less expensive engines in stride.

An exception to this rule is when the newbie has access to a modeler that is experienced in running such engines and who is willing to help with the break-in process. I am certain that over time, Magnum will refine its tolerances to equal or exceed other engine manufacturers, but then the prices will rise to nearly equal the traditional Japanese high quality engine prices.

At the moment, Magnum offers a great engine at a fantastic price, if one is willing to apply some knowledgeable TLC to the engine's first runs. Nothing good, or bad, lasts forever, so snatch up some of these engines while they are still cheap.