stunthanger.com
Engine basics => Engine set up tips => Topic started by: B Norton on June 19, 2017, 09:43:09 PM
-
After several attempts to get mine running consistently, it would run great about for about five or six laps go dead lean and stay there for the rest of flight. After running that way a couple of flights a couple of club member(Bob Reeves&Joe Gilbert) told me they thought it needed compression taken out of it.They were absolutely correct(nice to have experienced people to listen to).I pulled head off and hemied the head a little. Now it runs like like a big fox 35 has a distinct break to a hard two stroke when nose goes vertical.(I'm running a three blade 12-4.5 prop on my legacy)I flew five flights @five different rpm just to see if it would run that rpm throughout the flight starting @7800 all the way 8900 consistant all five flights!!It pulls that 68oz. legacy with authority! I would recommend
the magnum 52 if you need a big power for a cheaper price.
-
Glad that the engine you have is working withe lower compression, but what I have found over the years is that there is NO need to machine the head to reduce compression, I have a lot of Mag 52 and 53s out there, they run very well as I send them with high compression, use 5% fuel to start, and if your popping glow plugs add a head shim to reduce compression, many are running these with 18% synthetic fuel with either 2 ounces of castor or an ounce of Aero 1 fuel supplement. They do not like heavy oil or heavy castor fuels, the do great on a 13 x 4.5 or 12.5 x 4.5 prop 2 blades, 3 blade 12 x 4,5 and produce excellent power, much more than say and old ST 60 or a new ST 51
Randy
-
Randy thanks for the info this engine was tight when started before it would get stuck on compression stroke almost needed both hands to get it free .I'll differently be ordering one of your nice venturies for the next mag 52 I already have
-
Please see the attached.
Is this the one?
I shaved its head and installed new C/L venturi.
Now, I have to find a plane for it.
Thanks,
Matt
-
Now that's almost sexy! and that is the one !
-
I have been experimenting with this engine for a couple years. I have 2 Magnum .52s and 2 ASP .52s (same engine, different head. I favor the ASP version as the head is considerably lighter). I first powered a hand-me-down Strega with one. I currently am trimming out a new Brodak SV-11 powered by one of the ASP .52s. I hate to run low oil fuel in anything, so I had to decompress them with head shims to get them to run on 10-22 mix fuel.
Here is the first sloppy full pattern. The plane, handle and pilot still need a bit of trim :P
https://www.youtube.com/watch?v=oVSeO_-XC7s&t=1s
-
Fred
/
what prop are you using on your ASP 52 and SV11?
Also, what rpm are you setting the motor at before launch?
thanks
Carl
-
Carl,
APC 12.25 x 3.75, ~9400 ground setting at launch.
Fred
-
My Score with Magnum .52 from Randy Smith.
This video is last year. Not had many flights on it but pulls great.
Shug
https://youtu.be/UZOgwU6uj4k (https://youtu.be/UZOgwU6uj4k)
-
Fred
ran in to the same problem as yourself with my 2 new ASP's.
Checked the piston to head clearance and on both of mine, there WERE at .011" on each motor. (other motors might measure out at a different measurement)
Made up some head shims and they are now at .018".
they run very nice on the test stand using a xoar 13-4 and 10% fuel
Carl
-
Further development of my ASP/Magnum 52 powered Brodak SV-11 ARF.
Setup: cylinder boost blocked (JB Weld) and a .031" head shim (I need the head space as I use a lot of oil); 12.25 x 3.75 APC prop; fuel (10/22, half castor); Merlin 2011 plug; 7.4mm venturi; Randy Smith tube muffler with rubber extension; launch rpm approx. 9700; lap times 5.2 sec on 66 foot lines (line length).
I played with several mufflers and I found the Smith muffler to be the most suitable for this setup.
This is about the 10th full pattern, so I am still adjusting to the turn and will be experimenting with handle spacing. My goal is to use the ASP .52 in a modified Legacy (currently in the bones).
Fred
https://www.youtube.com/watch?v=sBYMjv1OLVQ&t=179s (https://www.youtube.com/watch?v=sBYMjv1OLVQ&t=179s)
-
Further development of my ASP/Magnum 52 powered Brodak SV-11 ARF.
Setup: cylinder boost blocked (JB Weld) and a .031" head shim (I need the head space as I use a lot of oil); 12.25 x 3.75 APC prop; fuel (10/22, half castor); Merlin 2011 plug; 7.4mm venturi; Randy Smith tube muffler with rubber extension; launch rpm approx. 9700; lap times 5.2 sec on 66 foot lines (line length).
I played with several mufflers and I found the Smith muffler to be the most suitable for this setup.
This is about the 10th full pattern, so I am still adjusting to the turn and will be experimenting with handle spacing. My goal is to use the ASP .52 in a modified Legacy
Are you running muffler pressure or open air uniflow?
Chris
-
My Score with Magnum .52 from Randy Smith.
This video is last year. Not had many flights on it but pulls great.
Shug
Shug what Xoar prop are you running? Fuel nitro/oil content?
Thanks
Chris
-
Chris,
No pressure, just suction on uniflow tank.
Fred
-
Great info guys your motors sound like they really are grovin! And look like pull both planes with authority thanks guys!!