Rcpilot

My Feedback: (78)

Okay, somebody told me the .52 is just a punched out .46. Seams obvious to me.

Then he went on to tell me that you could drop a piston and cylinder from the .52XLS into the .46 case. Effectively turning your .46 into a .52, but nobody would be the wiser. You'd have the best running .46 at the field.

I'm not too sure about that. If you read the specs, they have different strokes. The case might very well be the same. Maybe the cylinder thickness is just thinner on the .52 so it will drop right into the same case? I could believe this. (The old ST 2000 and 2500 engines were exactly like this. Same exact case and bore in the case. But the 2500 had a thinner wall on the actual cylinder liner. It was the same O.D. It was just punched out a little more on the I.D and thats how they got the extra 5cc out of it.)

But if they have different strokes--that means the .52 has a different crank. I don't see how you can stuff a larger crank into the same case.

The .52 could have a longer rod (I doubt it) --but that wouldn't change the actual crankshaft stroke.

Also, the heads look different. You'd HAVE to put the .52 head on top of a .52 cylinder--wouldn't you? I don't think it would be possible to put a .52 cylinder and piston inside a .46 case without also swapping heads. The .52 head is going to have a larger bore at the base, where it connects to the case.

Can anybody who owns BOTH engines comment?

w8ye

My Feedback: (16)

The head on the ASP 52(S) is not that much unlike the head on a ASP 46(S) or the Magnum XLS46 for that matter. They look alike externally

estradajae

As it is usuall, the .52 will surely have a different bore, slightly greater, but the stroke may be the same, as it is commonly seen that engines from within a range will have the same crankshaft. This means that if the cilynder has an increased bore, the cylinder head will be different on both engines. The stroke cannot me changed by a longer or shorter conrod, it but in a two stroke engine will change the timing and compression ratio as it will change the effective volume of the combustion chamber after closing the ports in a different "time"...

For example the os 46fx and 40 fx used the same conrod, crankshaft and so..but the cranckcase was different because of the bore and the number outside....the piston and sleeve were different because of the bore, and so the same to the cylinder head.

w8ye

My Feedback: (16)

The old XL 40, 46, & 53 had more commonality than the present XLS 46 & XLS 52

XLS 46
• Bore: 22mm
• Stroke: 19.6mm
• Displacement: 7.45cc
• Practical RPM: 2,000 - 17,500
• Weight (w/ Muffler): 16 oz
• Weight (w/o Muffler): 13.1oz
XLS 52
• Displacement: .52ci (8.47cc)
• Bore: 22.4mm
• Stroke: 21.5mm
• Practical RPM: 2,200 – 18,000
• Weight: 13.6oz (w/o Muffler) 17.4oz (w/ Muffler)

estradajae

It means that the only thing they may have interchangeable is the conrod??

carrellh

Not even the rod is the same...

Magnum Connecting Rod - XLS 40/46, XL 40-53
http://www.hobbypeople.net/gallery/280701.asp

Magnum Connecting Rod - XLS 52
http://www.hobbypeople.net/gallery/280713.asp

The 40 and 46 share some parts. The 52 is different.

Rcpilot

My Feedback: (78)

Different part numbers don't mean much. Tower lists different part numbers for various motors, but it's common knowledge that the parts will interchange.

I was wondering if anybody actually HAS both of these engines and would the parts interchange.

I got the .46 already. Runs great. I guess I'll have to buy the .52 one of these days and find out for myself.

The whole reason for this was because we are using the .46 engines on the World Models Sky Raider Mach II for some informal pylon racing. The rules are pretty simple. .46 sport engines with stock mufflers. Unmodified planes.

My friend is already trying to figure out how to bend the rules and he was the one who told me the .52 parts would drop into a .46 case. I was just curious if it would really work. I ain't doing it, but I want to know if it's really possible. He may show up one of these days and start kicking our butts, and I want to know if he's modified his motor. I run either the Magnum XLS .46 or an Aqua Craft .46.

The Aqua Craft was a turd until I got about 1 gallon of fuel through it. Then it suddenly came alive. Now it runs like a scalded cat. The Magnum .46 ran good right out of the box. I ran 2 tanks through it on the bench and started racing with it.

bigedmustafa

My Feedback: (2)

Pylon racing rules almost always have an "engine claim" rule where anybody can buy anybody else's engine for $100 or so to prevent exactly this kind of cheating.

The XLS .52A is around $90 plus the time and effort of swapping parts with the XLS .46A. Just take turns buying the cheater's engine and he'll get tired of putting in all of the extra work to cheat at a club series pylong contest.

If not, and he persists in modifying XLS .46A engines, eventually everybody will have one of his modified engines anyway.

Rcpilot

My Feedback: (78)

This is REALLY informal racing. We're just having fun. We have no "engine claim" rule in effect. We really have only 3 rules. It must be a sport .46 engine with a stock muffler. It must be a stock and unmodified airframe. You must use any fuel of your choice--not to exceed 10%. The rest of it is "honor system". We're all friends and just having some fun.

I doubt that he will go to the expense of buying the .52 parts--because nobody REALLY knows if they will fit. The person who told me these parts would interchange is a good buddy of mine. I have serious doubts that he'd actually do it--even if he was positive the parts would interchange.

My post was more curiosity. Not trying to catch the club cheater. Just curious. When I get some cash together, I'm going to buy a .52XLS and find out for myself. I have my doubts though--since the stroke is listed as being different on both engines. I could see a liner and piston dropping in. It's not difficult to overbore a liner. But with a different stroke on both engines--they would need to have different crankshafts and cases. I doubt it will work.

It wouldn't be fair anyways, and he knows it. None of the rest of us are dumb enough to think his motor suddenly makes his plane go 5MPH faster than all the rest, either.

Rcpilot

My Feedback: (78)

Okay, this myth is officially BUSTED

My friend ordered the Magnum .52XLS and he came over to my house tonight. I already have a .46XLS. We took both engines apart and tried to swap the internal guts. No joy.

The cylinder liner from the .52XLS is WAY to big to fit inside the case from the .46XLS

The piston from the .46XLS slips into the liner from the .52XLS, but it's obviously too small a piston for that cylinder. I didn't measure it, but there would be ZERO compression with the .46 piston inside the .52 liner. Probably a millimeter of clearance.

Didn't measure the rods because we didn't want to remove the wrist pin buttons and take the pistons off the rods. In my experience, removing plastic wrist pin buttons usually destroys them.

Didn't take the cranks out of the engines. No reason to. The specs list the .52XLS as having a longer stroke and from what I saw tonight--no reason to doubt that factory information.

Basically, we took the head and backplate off both engines. Removed the cylinder and piston assembly from each engine and tried to swap those parts. No joy.

Carbs are identical though. The .52XLS carb drops right into the .46XLS case. Appears to be same venturi size. Makes sense to me. No reason why the same carb wouldn't work on 2 engines that are .06 cubic inches different in displacement. I'll bet money the .52XLS engine needles about 1/2 -- 3/4 turn richer than the .46 for perfect high end tuning.

asmund

Great info We have been wondering about the same thing around here. So now I know that the internals from the 52 will not fit inside the 46 case as we suspected it might have.