RMX 40 with Jett Stream Muffler
10-22-2006, 06:50 AM
#1
Thread Starter
RMX 40 with Jett Stream Muffler
I used this rare engine as a backup for sport quickie racing. The RMX is not a OS copy and also not a labeled Evolution engine. I got it very cheap and gave it a try in my Q500 Sport racer.
Plug: OS Nr.8
Fuel: 20/80 FAI mix
Temp: 77°F
QFE: about 300ft
10x6 APC : 13400 rpm
10x7 APC 12200 rpm
10x8 Graupner Profi Prop (the black one): 13300 rpm
9x7 APC: 14200
The engine was barely run in (only a 3 minutes test stand session). I made 2 races with it for testing. It is a bit heavy but this is not a bad thing if you run it full throttle all the time.
It might be possible that nitro fuel will increase the rpm by 300-500. The case has a trapezoid geometry which makes it difficult to fit in the most Q500 back plate mounts.
It was easy to set up and remained working even if it was a little on the lean side. Because it was very cheap I peaked it to the limit without no mercy.
It seems like it was not harmed by doing this.
The RMX is not very high timed but with this muffler it ran very nice. My Super Tigre 40 unloads a little more in the air with the same muffler and prop.
Sorry. I have not tested the engine with the original OS-clone muffler. Because the engine is build massively I was able to drill out the mounting holes for the muffler to make the wider Super Tigre/Jett muffler fit. Originally it has the 37mm OS size. The Jett muffler has 38mm.
The noise is not as disturbing as I expected. With the 10x8 it sounds almost like an ordinary Trainer 40. Here is a Picture of the engine with the Jett muffler mounted.
Plug: OS Nr.8
Fuel: 20/80 FAI mix
Temp: 77°F
QFE: about 300ft
10x6 APC : 13400 rpm
10x7 APC 12200 rpm
10x8 Graupner Profi Prop (the black one): 13300 rpm
9x7 APC: 14200
The engine was barely run in (only a 3 minutes test stand session). I made 2 races with it for testing. It is a bit heavy but this is not a bad thing if you run it full throttle all the time.
It might be possible that nitro fuel will increase the rpm by 300-500. The case has a trapezoid geometry which makes it difficult to fit in the most Q500 back plate mounts.
It was easy to set up and remained working even if it was a little on the lean side. Because it was very cheap I peaked it to the limit without no mercy.
It seems like it was not harmed by doing this.The RMX is not very high timed but with this muffler it ran very nice. My Super Tigre 40 unloads a little more in the air with the same muffler and prop.
Sorry. I have not tested the engine with the original OS-clone muffler. Because the engine is build massively I was able to drill out the mounting holes for the muffler to make the wider Super Tigre/Jett muffler fit. Originally it has the 37mm OS size. The Jett muffler has 38mm.
The noise is not as disturbing as I expected. With the 10x8 it sounds almost like an ordinary Trainer 40. Here is a Picture of the engine with the Jett muffler mounted.
