kennyz

Sorry to bring this up again, so I'll be Quick. Yep I need a cheap engine..my os 46fx is loosing it's liner and needs bearings. ( Makes a nice paper weight at the moment!).
I've looked into the magnum xl52 the asp, evo's and just found the aviastar's. My main question is has the carb snafu been all squared away with the aviastars, I didn't see any recent posts and wondered whats up. Also will the carb off my fx46 fit the aviastar if needed ( I think its a 40a). And lastly I had a MACS pipe and header on the fx46..is anyone running a pipe on either the aviastar or a magnum xl52 ..if so what kind of numbers are you seeing. I'm leaning towards either of these two at the moment...mainly because of at least SOME U.S. support (sig and Tower). Thanx boyz...happy flying!

delman

Hobby People has the magnum 52xls on sale in their Model Airplane News add mar.10 thru apr.30 for 69.99 - your os carb would fit it if needed. I have been using an os 46sf carb on my 52xls.

NM2K

My Feedback: (14)

I have zero experience with the Aviastar, so I have no opinion about it.

I do have two or three (three if you count the ASP version as well as two Magnum versions) and these rascals smoke. I'm not saying that the Aviastar doesn't. But I KNOW the Magnum and ASP .52 two-strokes absolutely, most indeededly do smoke. It's probably a toss up on which engine has the best carb (Sanye versus the Aviastar).


Ed Cregger

jeffie8696

The aviastar ccarb problems are actually only a percentage of the total and Sig is fixing any that come to their attention without delay.
Ihave both 46 and 53 Aviastars and they run great when you get a good carb on them. Your OS carb may well fit, what is the stem diameter?
The 53 gives about 500 rpm over the same prop on the 46 on average. Weither that is worth the extra $20 is entirely up to you since the 46 is no slouch.
I have not heard of anyone using a pipe , in general the AV46/53 are newer generation engines happier at lower rpm with a bigger prop to comply with international noise regs at the flying fields. (I understand the Germans are also very strict)
do you lower the liner or raise it to increase the top end? The 53 does have an adjustable timing shim under the lip of the liner.

NM2K

My Feedback: (14)

The only way to talk about such things intelligently is to disassemble the engine of interest and then measure the timing/porting every way from Sunday. Hopefully there would be a real mechanical engineer in the audience available to do an analysis. No, not a software engineer, although all the ones I've met will tell you right up front that they know everything, so there will be no need to consult a mechanical engineer. (smile)


Ed Cregger

kennyz

The fx was set-up when I got it ( bought plane used rtf less rec). To my understanding the only time you mess with head shimms is due to detonation, the simpler fix is to use les nitro in your fuel. For a tuned pipe, your supposed to cut back the header a little at a time till the optimal operating range is found, if you cut off too much..Yep, your buying another header pipe. Thanks for the replys.

bigedmustafa

My Feedback: (2)

Lots of good choices here, kennyz. I helped a flying buddy break in and tune his Aviastar .46 last summer. He got one with a good carburetor and it was quite user friendly and powerful. I also own a Magnum XLS .52A and I've flown it for four or five seasons now. After disregarding the remote needle valve, it too broke in easily enough and has given me hundreds of exciting, reliable flights over the years. It still has a nice, tight pinch at the top even after all the flying I've done with it.

I'd be happy to buy an Aviastar .53 for myself. I'd also happily buy another XLS .52A from Magnum. I also own a JBA .56 2-stroke from http://www.kangkeusa.com, and that has been a superlative engine as well. The JBA isn't as responsive to a performance exhaust setup than other brands (at least according to Ed Moorman, an engine reviewer for RC Reports), but it is another powerful and reliable engine available at an attractive price.

Ed Moorman reported that the JBA .56 only picked up about 800 rpm when used with a Jett muffler. He never tried a full pipe and header, if I recall correctly, so your results could vary.

The Magnum XLS .52A really likes to run at wide open throttle to begin with, so it might be a great candidate for a header and pipe. The mounting lugs are a drop-in replacement for the .46 FX, and I have a hard time keeping my muffler completely snugged up on my Magnum XLS .52A anyway, so a replacement exhaust might be a good idea to begin with!

Good luck and good shopping!

kennyz

Well...I'm all done. I just order the magnum 52 from tower. I had a 10.00 off coupon which coverd the shipping so I got it for 69 bucks. A big part of my decsion is in part how the carb mounts (it's the same as my fx) and in part based on the user reviews on this site. Thanks for all the help guys..I'll let you know it runs with the tuned pipe after it's al broke in.

Turk1

Check frequently the carb holder screws of Magnum engines.They are famous to fell off.

jeffie8696

Kenny, there are a set of shims on an Aviastar 53 that are under the rim of the liner that will raise or lower the height of the liner in the case. This has an effect of changing the port timing. However I have no experience doing it. Ido know it will affect the compression ratio so if you were to remove a shim you would have to install a head gasket to keep the comression ratio the same.

jag215

I have an Aviastar 53 on my Sig Lt-40. The engine seems to be leaking fuel through the head somewhere. Has anyone encountered a problem similiar to this?

jeffie8696

First time Ihave heard. If it is still under warranty Sig will take care of it. I must assume you have checked the tightness of the bolts.

MetallicaJunkie

yeah mine did that...i put a bead of permatex anaerobic gasket maker, and that problem went away... the engine runs great now....

i can not recommend one because the stock carb was crap on mine and the leaking head...

jeffie8696

Ihave about 7 in my collection and none have had a head leak. Bad carbs and even a bad rod but all fixed under warranty and all good now.