NM2K

My Feedback: (14)

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A seven pound model with that short of a wingspan is going to be a handful at low speed. Be careful and be sure to keep it moving fairly fast on approach.

Getting off the ground safely will be the most difficult aspect of flying the model with the engine that you presently own. Once airborne, the .40 should handle it fine. Getting airborne off a grass field of average height may prove to be a challenge.

The Goldberg Cub typically weighs in at a bit over 7 lbs. and will fly fine with an average .40 two-stroke. Some have even flown it with a .40 four-stroke. However, the Cub does have considerably more wing area than I suppose your model has, if the 51" wingspan is accurate. My eyes are blurry, so I may have misread the dimension. I hope the model has a 61" wingspan in order to contend with that much weight. Good luck.

jstanton

My Feedback: (14)

RcKrazy

I have looked up the spec's on the Great Planes Cessna 182 ARF that is a 40 size. Your wing area on yours you stated is 615sq in. I think your wing span must be more that 51 in. As your can see on the Great Planes 182 Cessna the wing area is smaller that yours but the wing span is 65". I bit your Magnum 40 will fly this plane just fine. I would still hook up wing a local instructor at your field and have them do a test run for you first.

Goood luck!

Specs on the Great Planes 40 Cessna 182 ARF.

REQUIRES: Engine: .40-.51 (2-stroke) or .52 (4-stroke)
Muffler: Pitts-style for 2-strokes (engine mounts on its side) OR if
using a 4-stroke, the stock muffler will work fine.
Radio: 4-5 Channel
Servos: 5 Standard (2-Aileron, 1-Elevator, 1-Throttle, 1-Rudder)
Servo Extension 6": 2
Y-Harness: 1 (for aileron servos)
Misc. Items: Glow plug, 1/4" foam rubber padding, medium fuel tubing,
fuel filter, propeller, building and field equipment.

SPECS: Wingspan: 65.5" (1657mm)
Wing Area: 578.69 sq in (37.32 dm2)
Weight: 6 lb (2.7 kg)
Length: 48" (1219mm)
Wing Loading: 23.5 oz/sq ft (72 g/dm2)
Airfoil: Semi-Symmetrical, High-Wing
Scale: 1/8 to 1/9 (approx.)
Center of Gravity: 3" (76 mm) back from the wing's leading edge
Control Throws: Low Rate High Rate
Ailerons: Up & Down 1/4" (6mm) 1/4" (6mm)
Elevator: Up & Down 7/16" (11mm) 7/16" (11mm)
Rudder: Right & Left 1-7/8" (48mm) 1-7/8" (48mm)

William Robison

My Feedback: (3)

RcKrazy23:

Several years ago Hobby People had a "Deal" - buy the RCM 40 trainer at the regular price, they would throw in a Magnum XLS 40 engine at no additiional cost.

The moment I saw the ad I grabbed the phone, but even being so fast their sales were such that I was about number 240 on the back order list. Thwy did honor the price, and about six months later it came.

I still have the plane, and it still flies with the Magnum XLS 40 engine. And flies very well.

THe point of this is that we tend to overpower our planes, this RCM 40 will loop nicely from level flight even though it wont do a vertical climb out of sight. It does not need to.

And your 40 engine will most likely fly your plane very nicely also.

Bill.

RcKrazy23

My hobbico cessna 182 has been discontinued along time ago. The specs for the Great Planes cessna is different from mine. I'll have to get some pictures posted as soon as I can.

I'm also looking for a scale to weigh my plane on as my bathroom stand scale wouldn't be accurate for my bird.

estradajae

HI Bill!

I've seen that you a re a ery experienced man on this, and by trusting you I´ve just placed an order for a MAG .46XLS from Tower..This engine is by now the cheapest .46 engine available, only $59.99..I liked to try the mag anyway... I have a previous experience with a .46FX and I run this engine with a Scimitar 11x7 prop, it seems he likes the master props the most and hates the apc the most too..(don't know why..sometimes the plane just didn't take of, does anybody know why??)...anyway the question is that if you have experience with the MAG running this prop?...becouse for the kind of planes that I use (like pattern type ones) it seems to be the best. Do you have any recomendations for breaking in? I always use a own mix fuel for my engines, and I don't use nitro...nitro is unavailable in my country, the only way you can get is by the peple that import it directly and it's very very expensive, I guess it will run ok on it as my FX... Sorry if I'm asking too much!! and thanks

Jorge

William Robison

My Feedback: (3)

Jorge:

I have a little Magnum GP 25 that's about as old as its size, roughly 25 years old (maybe only 20, don't really remember when I got it) that has flown from new on a Goldberg Eaglet, it and the airplane are still in excellent condition.

About 15 years ago when I was bashing my first "Big" home-built twin I got a used Midwest 40 size trainer, it had a Magnum XL 46 engine in it. That engine impressed me so greatly that I canceled the order for a pair of OS 46 engines and got another pair of Magnum XL 46 engines for it. That plane is still fine, and the original Magnum XL 46 engines are still in it. I fly them with Zinger 10x6 three blade props. I've also flown these engines satisfactorily with 12x6 MAS. I don't like APC, so I don't have experience to comment from.

Since that time I have not bought another new OS engine. I have gotten a couple in trades I'll admit, and one trade I made just to get the new OS 46 FX engine on the plane. I wanted to see how long it would run before it peeled the liner. Sad to say, that &*^% OS engine is still running fine. It has been a big disappointment.

I still have a pot full of K&B ringed 40 and 61 engines, when they are a good fit I'll use one (or a pair) of them, but when I want a two stroke screamer it's always a Magnum. I have never been displeased with one.

Anyway, that's my story.

I have to admit hearing not such nice things about the Magnum XL 52 engines. One of my local flying buddies, who also happens to be a twin flier has not been able to get a pair of 52s to work in a twin, and others have posted about problems with them. I've not had a 52 size Magnum, so I can't comment on that one engine.

In the larger engines the XL 108 and now the XL 120 have been no problem, it's just the 52 that I hear nasties about.

Fuel. Home mix is fine, hope you are using some castor oil in it, doesn't have to be all castor, but at least 3-4% castor, and 15-16% synthetic is OK. At least 18% total volume of oil for the Magnums.

For break in run the engine at full throttle, richened about 500-600 from peak. Do this for a couple tanks, then fly the plane at the same setting. As you fly it gradually lean it out until you're flying 200-300 rpm off peak. Start leaning the idle as you lean the peak, when you get it consistent at 300 rpm off peak you should have the idle set also.

One problem. The Magnum engines are set up for 15-20% nitro. Pull the head, pick the head gasket out, put the head back on. This will raise the compression, it will run better on zero nitro that way. Do this before you run the engine, with everything clean and new you should get a good seal without a gasket. If it leaks you can lap the liner to the head to get the seal.

Hope this helps. If I've missed a question yell at me, I'll make another post.

Bill.

estradajae

THanks for your quick answer Bill!

I use castor on my fuel...synthetics are very expensive too...with the price of a quart of klotz here, I can mix a gallon of fuel with castor oil. Castor oil here is something you can buy easily and cheap, but it doesn´t have tha quality grade that you may have there, but never a problem with my engines, they are like new!!..

About the head gasket..I don't know...I'm afraid to remove it...since it's a new engine and don`t want to disassemble it, maybe I'll try it first with the gasket on.

Ah, about your old engine...I do have an OS 25 that i think its from 1975 or so, i know the date becouse i saw the pic in the OS page, in the timeline...it was my first engine..and I'm only 21! that engine is older than me for almost ten years...it is one that has iron piston and a flange on it, vertically placed...I don't know which is the proper word for that thing in english (I do spanish hehe)...but anyway, that engine runs fine..it powered my first scratch planes...a control line one...that died at the first day of flight..and my first R/C...those were hard times for me!! I did it all alone hehe...

Jorge

estradajae

THanks for your quick answer Bill!

I use castor on my fuel...synthetics are very expensive too...with the price of a quart of klotz here, I can mix a gallon of fuel with castor oil. Castor oil here is something you can buy easily and cheap, but it doesn´t have tha quality grade that you may have there, but never a problem with my engines, they are like new!!..

About the head gasket..I don't know...I'm afraid to remove it...since it's a new engine and don`t want to disassemble it, maybe I'll try it first with the gasket on.

Ah, about your old engine...I do have an OS 25 that i think its from 1975 or so, i know the date becouse i saw the pic in the OS page, in the timeline...it was my first engine..and I'm only 21! that engine is older than me for almost ten years...it is one that has iron piston and a flange on it, vertically placed...I don't know which is the proper word for that thing in english (I do spanish hehe)...but anyway, that engine runs fine..it powered my first scratch planes...a control line one...that died at the first day of flight..and my first R/C...those were hard times for me!! I did it all alone hehe...

Jorge

estradajae

Hi bill its me again!

I just received my new 46xls and I did the breaking in so far, but I'm pretty concerned about the initial settings of the low needle because it came with no gap between the spray bar and the needle, so I decided to open it to achieve a 1.5mm gap between them. This is normal for this engine to have no gap and I'm wrong. Initial factory settings call for 2 1/2 turns, but at this setting, the throttle barrel just don't close completely, so I think that there is a mistake in the manual or something... my .46fx has a 1.5 mm gap so I did it in the magnum, but since it's not fully broken in I didn't tried to idle it. What is your recomendation.??

Ah offcourse, my Magnum is a screamer with a 11x7 prop!! what a great deal, I'm very happy with it and I think it will give me lots of fun!

Ernie Misner

My 46 XLS just took off and ran with the usual leaning and tweaking of a new engine. Try doing that and see what happens without worrying about the usual spraybar and needle distances. These are engines that just "want to run", as compared to my 52 that gave problems with the same exact carb.

Ernie

William Robison

My Feedback: (3)

Jorge:

You made one small error in setting the LS needle.You have to count the turns with the throttle closed. If done from open throttle the setting will be 6-7 turns open - if you watch in the throat as you turn the LS in you'll see it coming further into the throat, it will hit the spray bar and stop the barrel's inward movement as you close the throttle.

So close the throttle, reset the LS to your 2 1/2 turns out and try again.

Hope this helps.

Bill.

estradajae

Thanks Ernie and Bill

Bill, I did it with the barrel closed, and doing that, with the factory settings on the needle that there is no gap, thats why open the needle to achieve gap...but I'm going to reset the needle with the barrel closed and see what happens this afternoon, I'm going to finish the break in and do some work on the needles... I expect, if there is no gap, that there is a lot of interaction between the needles!

Thanks for your Inputs!
Jorge

Ernie Misner

Let us know how it runs, that should tell the story.

Ernie

estradajae

I ran the engine this afternoon, and had some time working on the needles... i started with the LSN with a 1.5mm gap, but this was SOOOO much rich for this carb, so I had to lean it gradually, and it finished almost in contact with the spray bar, I mean no gap, and there was no noticeable interaction between the needles at this time as I was expecting. It seems that the engine likes to idle a little rich by now, but I have to wait untill it is fully broken in (I have run 4 11oz tanks already) to have it a little leaner as it hesitates, but it cannot ve leaned right now. I'm very happy with the power of the engine, becouse it is more than what I was expecting...and tomorrow I have a maiden flight, so I'll tell you how it goes on the air!!

Jorge

flyierjon

Hey maybe you guys can help me with my magnum engine!
I have a 4 stroke 91 magnum. Well i tried to start it about 2 weeks ago and well i have very little compression and it wouldn't even kick over once. I had to (try to) start it useing a chicken stick because I have to get a new electric starter (mine died) any ideas????
Thanks!!!
Jon

w8ye

My Feedback: (16)

Did any compression return after getting fuel in the engine?

Model fuel doesn't start well below 50 degrees when trying to hand start.

Did you get any fuel into the engine?

flyierjon

yes i had fuel comming out of the carb so i am pretty sure it was getting into the engine... i even took the glow plug out and put a few drops of fuel in there and it kicked once. This engine im now haveing problems with has about 200 or so flights on it. It was a very good engine! I also checked to see if both valves were moving and they were fine! I just cant think of anything else to do.

w8ye

My Feedback: (16)

At this point, you need to possibly read some of the cold weather starting threads IF YOU WERE OUTSIDE AND THE ENGINE WAS COLD.

These most often conclude using at starting aide fluid with a vapor point much below that of alcohol such as lighter fluid.

flyierjon

so magnum engines really have a very low compression? and why is this?

w8ye

My Feedback: (16)

Not normally but some do. They have a leaky valve or ring. If you lesten in the muffler or the carb, you can hear a leaky valve.

One thing i'm trying to say is that glow engines don't like to start in cold weather!

One other thing is did the compression improve any by getting fuel into the engine?

flyierjon

yes the compression did improve a little with the fuel. so if i got some lighter fluid into the carb somehow and use an electric starter, it would start probably?

boggey090

I have a Magnum 46 on a Piper Cub j3 with pitts muffler. Lately it will not shut with the throttle cut and it drips a lot. The clean up is messy however it is running good. I am sure it is sucking in air causing it to not shut. Any suggestions on how to eliminate this problem would be greatly appreciated.[sm=spinnyeyes.gif]

William Robison

My Feedback: (3)

Do rmember please - with the throttle shut or at a low setting it is normal for the compression to feel quite low in a 4S engine. Always check it with full throttle.

Bill.

w8ye

My Feedback: (16)

The only problem is how to get a little lighter fluid into the four stroke engine

flyierjon

is it possible to let it drip into the top of the cylinder and put the glow plug back in quick. would it stay in there long enough?