Zeus
08-11-2018, 02:05 PM
#251
Thread Starter
Finally got Zeus onto the field and got three flights done. In spite of the big fuselage it is reasonably fast. The 50 is pretty quiet with this prop and has plenty of power, Still needs to be run in though so it is a bit rough as yet. Without any mixes and elevator trimmed for level flight it pitches to the bottom and no roll couple in left rudder KE. Right rudder KE it pitches up and has proverse roll. None are strong. Down lines it pitches up. I expect to trim out the pitching with stab incidence. The CG is well forward and I have the ballast tube in the tail to easily adjust the CG. Suffered a bit of damage to the UC when I caught the wire at the end of the runway so I will take the opportunity to run in and adjust the motor properly on the bench.
09-16-2018, 05:58 AM
#254
You do as you feel but I am of the camp that flying is the best way to run in an engine. Varying load and better cooling in the air are the primary reasons.
Way cool project and wishing you good flying and trimming to work out the bugs of a new design.
Ken
Way cool project and wishing you good flying and trimming to work out the bugs of a new design.
Ken
09-17-2018, 02:24 PM
#255
Thread Starter
Hi Ken. I agree with you and that is what I usually do. However this motor has been vibrating a lot and isn't doing the airframe much good, so I am going to sort it out on the bench. Specifically it has a mid range burble which is causing the vibration. It seems like DA has addressed this problem with the DA35 which has some sort of mapped ignition timing. So I am wondering if this motor on a pipe will be a better option.
09-17-2018, 02:31 PM
#256
Thread Starter
Hi Dan see my above post. I used the DA 50 as I had one on my bench. I thought it would be a fun model and it does fly well with 50 apart from vibration. I would certainly like to put a YS 200 in it, but can't justify the expense at the moment. I think the petrol two strokes could benefit from a more controlled fuel mixture and ignition system. I need a few days to sort out some small repairs but am busy making large propellers at the moment.
09-18-2018, 12:17 AM
#257
Finally got Zeus onto the field and got three flights done. In spite of the big fuselage it is reasonably fast. The 50 is pretty quiet with this prop and has plenty of power, Still needs to be run in though so it is a bit rough as yet. Without any mixes and elevator trimmed for level flight it pitches to the bottom and no roll couple in left rudder KE. Right rudder KE it pitches up and has proverse roll. None are strong. Down lines it pitches up. I expect to trim out the pitching with stab incidence. The CG is well forward and I have the ballast tube in the tail to easily adjust the CG. Suffered a bit of damage to the UC when I caught the wire at the end of the runway so I will take the opportunity to run in and adjust the motor properly on the bench.
Regards
09-18-2018, 06:09 PM
#258
Hi Ken. I agree with you and that is what I usually do. However this motor has been vibrating a lot and isn't doing the airframe much good, so I am going to sort it out on the bench. Specifically it has a mid range burble which is causing the vibration. It seems like DA has addressed this problem with the DA35 which has some sort of mapped ignition timing. So I am wondering if this motor on a pipe will be a better option.
I'm not a 2C gas engine guy even though I'm a former Stihl tech. (hate the chain saw sound). But from what I read and have seen this seems to be a common problem. From what I know a large part seems to be a carburetion issue. These carbs do not have the midrange calibrated. Basically they are idle and WOT. I've heard it can be tuned out to some extent but the engine needs to be well broken in first. You'll get it figured out as that is the type of person you are. Great project, good luck finding the issue.
Ken
