bbrown2828
150cc
Y did you have to adjust timing
Gp-61
- Thread starter gyro
- Start date
Yowzilla
50cc
Ok...I got some more data, after setting timing with timing kit..now no joke 29*
I have two data sets. The first (good sound) was with needles leaned out that eliminated 90% of the gurgling at mid. The second was (bad sound) with both H and L needles richened 1/16 each which produces significant more gurgling at mid.
Question: I am fairly confident I need more gallons before the engine temps comedown, but looking at average temps I am Ok. Should I set needles to minimize gurgling or concentrate on lowering temps.
Also wonder if my cowl is too tight on engine as possible cause of temps. Pic attached.
Attached is the telemetry from two of my 6 flights Sunday.
Both 24x9 Falcon, On 4th Gallon, 92 Octane, Redline 40:1, thermocouple at middle fin back of motor
Good Sound File
Max Temp 314F
Avg Temp 254F
Max RPM 8126
Bad Sound File
Max Temp 303F
Avg Temp 246F
Max RPM 7996
I have two data sets. The first (good sound) was with needles leaned out that eliminated 90% of the gurgling at mid. The second was (bad sound) with both H and L needles richened 1/16 each which produces significant more gurgling at mid.
Question: I am fairly confident I need more gallons before the engine temps comedown, but looking at average temps I am Ok. Should I set needles to minimize gurgling or concentrate on lowering temps.
Also wonder if my cowl is too tight on engine as possible cause of temps. Pic attached.
Attached is the telemetry from two of my 6 flights Sunday.
Both 24x9 Falcon, On 4th Gallon, 92 Octane, Redline 40:1, thermocouple at middle fin back of motor
Good Sound File
Max Temp 314F
Avg Temp 254F
Max RPM 8126
Bad Sound File
Max Temp 303F
Avg Temp 246F
Max RPM 7996
Yowzilla
50cc
I know I am asking for it all, but when this engine is on song i enjoy flying more. I fly slower and lower. A certain temp dose not help the fun factor. A good enough RPM somewhat. But a constant sound is real feedback you get every second.
It may be an attribute of my exhaust that highlights the popping and gurgling.
The 24x9 prop helped a ton!!
I have not found a YouTube of this motor that sounds as rough as mine, and want to insure I am not overlooking something obvious.
The only data that I question is the accuracy of my temp and at correct location on engine. I may just get over it and ignore the temperature average that is a little higher than recommended and tune for solid as a rock transition. It might go without saying but this is my first gasser.
It may be an attribute of my exhaust that highlights the popping and gurgling.
The 24x9 prop helped a ton!!
I have not found a YouTube of this motor that sounds as rough as mine, and want to insure I am not overlooking something obvious.
The only data that I question is the accuracy of my temp and at correct location on engine. I may just get over it and ignore the temperature average that is a little higher than recommended and tune for solid as a rock transition. It might go without saying but this is my first gasser.
PropBuster
50cc
two things come to mind from the photos, just some suggestions: you could go up in size of the cutout around the head, is that gap too tight? The other thing is exit area, it looks like there isn't much flowing out the bottom of the cowling besides the tunnel vents - but I see all sorts of types of cutouts on pics of planes. Mine is like this, the third picture down http://www.3dhobbyshop.com/72-Extra-330SC--Red_p_15148.html
Some others look sealed up much more. I can't remember the ideal inlet/outlet ratio right now. 1:3 ? 1:2 ? Plus that is not exactly easy to measure, I'm interested to hear what everyone else does
Some others look sealed up much more. I can't remember the ideal inlet/outlet ratio right now. 1:3 ? 1:2 ? Plus that is not exactly easy to measure, I'm interested to hear what everyone else does
The mid range does not usually smooth out till after 4 gallons, also make sure you tune the high end first then the low end then check the high again. Also make sure your carb does not have anything in it pull the needles and check the screen. These are two stokes after all so they will miss some unless they are wide open that is just the nature of them. Also the lack of a midrange tract or needles on the carbs does not help.
Yowzilla
50cc
Thanks for the inputs. 1. I am convinced I need to open up cowl for exiting hot air and will open around the head. It can't hurt.
I just reviewed some of my flight videos over the past few weeks. My conclusion is this rocket engine is sounding better and better every weekend. I just need to focus on flying more than tuning. I will let the engine free up as the gallon count adds up.
I just reviewed some of my flight videos over the past few weeks. My conclusion is this rocket engine is sounding better and better every weekend. I just need to focus on flying more than tuning. I will let the engine free up as the gallon count adds up.
Yowzilla
50cc
Cooling was confirmed to be my issue and I have the data to prove I did not cut my cowl enough for entry and exiting air. I opened up around the cylinder about a finger width and 3/4 in more on the top of the cylinder opening. I also opened up a new hole behind the two muffler pipes. Not sure which was the best cut, but results show almost 100F reduction in Temps!!! I leaned out the Low needle in the data set attached and had minimal popping a gurgling. When it did it was in the expected 10% throttle range. I am extremely happy with the sound of this power power plant now....
Lesson learned....Air cooled engines need AIR!!!! Gasser Newby mistake to opt for looks over cooling in the cowl cuts. Attached is the before and after. It is amazing how drastic the temps dropped with minimal cuts.
Only 2 flights today in 20mph winds with 10mph gusts on top...
Lesson learned....Air cooled engines need AIR!!!! Gasser Newby mistake to opt for looks over cooling in the cowl cuts. Attached is the before and after. It is amazing how drastic the temps dropped with minimal cuts.
Only 2 flights today in 20mph winds with 10mph gusts on top...
Glad to hear!