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Magnum XLS .52A

Old 09-03-2010, 04:24 PM
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qwertypemdas
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Default Magnum XLS .52A

I just want to share my experience with the Mag 52 so far. So I bought it NIB from a guy at my club so no warranty, but I got it for $40 so I can't complain. Broke it on on an apc 11x5 and hangar 9 sport plug with 3 tanks of fuel. The hangar 9 plug wasn't hot enough, then i tried an os 8 and that was a little cold too, so went a got an os #6 and that did the trick pretty well. Then I started tuning up on an apc 12.5x3.75 and it seems to rev plenty high (13,000) and produced about 8lb of thrust. Then started a long journey through tuning the low speed needle. Now the instruction manual says to set the low speed needle 3 turns out... now idk what they're doing over at the magnum factory but 3turns out isn't gonna get you anywhere. The correct setting for the low speed needle is about 3/4 of a turn out and then play with it from there. The highspeed needle is obviously much easier to set but it varies from prop to prop. Now once I got it to jump from idle to WOT without any problems I started at idle and then VERY slowly advanced it 1 click at a time and it always seems to quit at about half throttle... I figured that's ok since I don't throttle that slow so then I went out to fly. Now a quick thing, I used one of the 3 supplied muffler gaskets and I locktited and REALLY torqued down those muffler bolts. So I decided to put this puppy on my mojo 40 since it was way underpowered with it's Royal .45 engine. The engine starts right up really easy but it will many times start backwards. I recommend and electric starter to minimize the chance of reverse starting. Then of course I revved it up and it was doing just fine so I decided to just take off and see what happens. On the runway it went to WOT with zero hesitation and i was off the ground in about 5 feet and I was very quickly accelerating vertically, this was a big surprise because my mojo used to take most of our entire 550 foot runway to get off the ground. Once in the air it didn't seem to have any problems so I brought it back down to check everything and it was all doing just jolly good. Took it up again and after about 5min it goes RRRRRR rrrrrrr RRRRRR rrrrrrrr, indicating extreme leaning and it was quite a bit louder... yup you guessed it, the muffler. One muffler bolt had squirmed loose and the other was quickly following, now a guy with a big 50cc plane called landing so I had to puts around in the air for another 2min at 1/4 throttle trying to keep it together. It was a rather uncomfortable situation. I brought it down and saw the muffler was half taken off and and gasket was gone. So I replaced the gasket and then took it up again. I landed shortly afterward to find that the gasket had been squeezed out the sides and the muffler was now loose again... I decided the whole gasket idea was rubbish so I took out some new, oil free, muffler bolts and assembled the muffler back on the engine with some locktite and torqued it down good. After about 5 mre flights the muffler seemed to be on there just fine and it wasn't moving at all. However, castor oil seemed to be getting all over my plane and what i didn't notice was the cone on the end of the muffler was spinning around in flight... because it was loose. So after going through all this I thought it was all good and then the next flight I deadsticked because of the midrange problem. I have yet to find a solution to the midrange problems but I can tell you this engine has plenty of pull, plenty of noise, and the muffler doesn't like to stay where you put it. Btw I run an apc 12x4 because the 12.5x3.75 was making big vibrations. The 12x4 still makes some vibration but it's better and i think it pulls better for 3d. If you get this engine forget the muffler gasket, tighten the bolt that goes through the muffler and locktite and torque the muffler bolts really good. I might get a macs one piece muffler or the tower muffler for more power but the stock one seems to work fine, the extra noise this engine makes is from the vibration at high rpm. Any tips or anything would help for the midrange issues. I hear some people use different carbs on this engine so idk. not time for me to proof read this so figure it out :P
Old 09-03-2010, 04:44 PM
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asmund
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Default RE: Magnum XLS .52A

I was gonna tell you too loose that muffler gasket, but you figured that one out yourself (they are the cause of the loosening muffler bolts) The engine itself is not vibrating more than any other engine, you just need to start ballancing your propellers. My low speed needles are set at somewhere between 0.5-3/4 out from closed and I have no problems in the midrange what so ever with my two XLS 52`s (I do use the Tower muffler though) We have several XLS 52`S around here doing hovering (plenty midrange running) and other 3-D and none deadsticks or have any issues. Are you absolutely sure that your engine doesn`t suck false air under the carb or around the back plate?? I seal every engine I own with some locktite sealant in those places, just to be sure.
Old 09-03-2010, 05:11 PM
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Default RE: Magnum XLS .52A

The Macs one piece muffler doesn't give any trouble about falling apart or tuning but it robs about 500 rpm off the top rpm.
Old 09-03-2010, 08:27 PM
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qwertypemdas
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Default RE: Magnum XLS .52A

Well I think I just gotta play around a lil more with it. I did PLENTY of hovering but flying at idle for a very long time and then trying to go vertical it will bog a bunch and the dead stick only happened once and I forgot how so idk about it :P I've never had an engine who's muffler didn't come off (except my 40cc gasser) so I'm glad this gasket thing worked out lol.
Old 09-04-2010, 09:39 AM
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Default RE: Magnum XLS .52A

Hello Asmund, what glow plugs are you using with your ASP/Magnum XLS 52 ? I'm using OS #6 (A3) in mine and have occasional mid range flameouts in my 3D profile, performing low speed harriers.
Old 09-04-2010, 09:52 AM
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Default RE: Magnum XLS .52A

If you are using the A3 I would lean out the low speed a little bit more to see if you get out of the bogging down condition.
Old 09-04-2010, 12:52 PM
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Default RE: Magnum XLS .52A

When your engine is diling and you stop the fuel supply by sqeezing the fuel tube will the engine rpms increase slightly before dying? Depending on the engine it can take a few seconds.
Old 09-06-2010, 08:21 PM
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Default RE: Magnum XLS .52A

I love my Magnum 52, but can't say the same for the muffler. The engine is on the Gt. Planes Ultra Sport 40 that they did a limited run of kits on a couple of years ago. With retracts, the plane flies like my old piped pattern planes. But....the factory muffler rear cone insisted on twisting in flight, with the "stinger" scorching the fuselage paint job. I cleaned it all up, JB Welded the seams, and for good measure, drilled and tapped the seams for 2/56 Allyn head bolts.
After a few flights, it sheared the bolts off. So I tried a Tower 46 muffler. Engine was probably even faster. But I had many of the same problems. Finally, I had an OS 50SX that I was using with a Pitts style muffler, so I tried the OS muffler, and lo and behold, the bolt pattern is the same. This lowered the rpm a little, but my problems went away.

Why do I think this problem may be occurring? I wonder if it isn't a difference in heat, between the cast front part, the thin shiny part in the middle, and the cast part in the rear, with a variance in expansion under heat when running?
I'm no engineer, but I suspect this may have something to do with it. Any comments will be interesting.

Clair Sieverling
Old 09-06-2010, 08:29 PM
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Default RE: Magnum XLS .52A

You are correct about the difference in expansion rates but the center bolt has yet another expansion rate
Old 09-06-2010, 10:52 PM
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Azcat59
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Default RE: Magnum XLS .52A

w8ye, You are right about the center bolt (steel) having a different expansion rate than the aluminum components. One would think however, that it would expand less than the aluminum, resulting in a tightening of the bolt and thus making it harder for the rear cone to rotate. A mystery indeed.....

Clair
Old 09-06-2010, 10:58 PM
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Default RE: Magnum XLS .52A

I had several of those Tower mufflers at one time and I had to run a 6-32 threaded rod all the way through the muffler with double nuts on each end to keep them together
Old 09-07-2010, 11:45 AM
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asmund
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Default RE: Magnum XLS .52A


ORIGINAL: HFrank

Hello Asmund, what glow plugs are you using with your ASP/Magnum XLS 52 ? I'm using OS #6 (A3) in mine and have occasional mid range flameouts in my 3D profile, performing low speed harriers.

I use mostly OS 8, but have used a number of different ones (also A3), never been a problem no matter what plug I use.
Old 09-07-2010, 08:12 PM
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Default RE: Magnum XLS .52A

Sheared the bolts off? That's a new one, sounds like they were REALLY overtightened or the muffler was really heavy since you modded it and you had high vibration. It seems fine now i did a bunch more flights with everything just torqued down. The cone doesn't spin and the muffler is secure and the midrange is reasonable. The low end is set a bit lean but midrange is really rich..... Maybe i'll grind out a different low speed needle shape and experiment with that.
Old 09-07-2010, 08:19 PM
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Default RE: Magnum XLS .52A

grind out a different low speed needle shape and experiment with that.
You need to put a curve in the cam slot in the throttle barrel
Old 09-07-2010, 08:40 PM
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qwertypemdas
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Default RE: Magnum XLS .52A

w8ye, you are exceedingly wise, idk how you come up with this stuff but yes that does seem more reasonable than making a change to the needle shape... I'll look at it for a while and come up with something... this only problem is the barrel a tight fit so i can't mess it up to much or it will bind. Also i need to find out what's going on with the resonant frequency at hi throttle, it's make the connecting tube from the remote need to the carb vibrate like crazy. i might convert it back to std needle placement but it's a hassle the way it's mounted lol. I have run too many engines to count and probably a few hundred props and i have never balanced any of them, even my 20x8's all seem to be in reasonable balance but i don't have a balancer so i'll probably pick one up soon.

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