1/5ish scale Red Baron RB-51
08-28-2015, 03:04 PM
#56
I might go to 19X12 props in the future but right now the plane flies nicely in the 1/2 throttle range and is easy on the amp draw.. In the video I never went past 3/4 but do not expect much speed difference with the 10" pitch props at full throttle.. I never intended for the plane to be a racer persay. I wanted it to look like the RB as much as possible and present well in the air. If it will fly in the 80-100mph range it will do the full scale justice I think...
09-21-2015, 02:03 PM
#59
Couple more flights in Sunday.. Some video..
https://www.youtube.com/watch?v=KKavOtcX8V4 https://www.youtube.com/watch?v=QiY_mkAKCVU
https://www.youtube.com/watch?v=KKavOtcX8V4 https://www.youtube.com/watch?v=QiY_mkAKCVU
Last edited by TheRickster; 09-21-2015 at 02:05 PM.
09-22-2015, 12:20 AM
#60
Looks and sounds good!
There was something bothering me about the overall impression, though. Perhaps I felt a mismatch between speed and sound? Could you get about the same speed with lower RPM?
There was something bothering me about the overall impression, though. Perhaps I felt a mismatch between speed and sound? Could you get about the same speed with lower RPM?
09-22-2015, 05:14 AM
#63
Both props are 20x10. After each flight the mah usage has been within 150mah between the 2 packs which leads me to believe the current load to be about the same. With the setup as it is the battery temp is only warm and flight times are satisfactory. I am going to try some 19x12 props in the future..
09-22-2015, 05:27 AM
#64
My Feedback: (43)
I ask because I researched doing this conversion awhile back to a Top Flite Mustang. Supposedly the rear prop needs more pitch since the air has now been accelerated by the front prop.
The pattern guys have done exhaustive testing on this with the 'contra-drive' system. Of course they use one motor and a gear box so differential current draw is not a concern.
Perhaps a 20x10 in the front and 19x12 in the rear. The half inch on each side would probably not be noticeable on the ground. In the air, you may notice a slightly different disc size on low fly by's.
I still have not ruled out doing this to my Byron's Mustang since it has a nice long engine compartment to put the motors and batteries in.
No matter what, you did a great job and I think its awesome!
The pattern guys have done exhaustive testing on this with the 'contra-drive' system. Of course they use one motor and a gear box so differential current draw is not a concern.
Perhaps a 20x10 in the front and 19x12 in the rear. The half inch on each side would probably not be noticeable on the ground. In the air, you may notice a slightly different disc size on low fly by's.
I still have not ruled out doing this to my Byron's Mustang since it has a nice long engine compartment to put the motors and batteries in.
No matter what, you did a great job and I think its awesome!
09-22-2015, 05:39 AM
#65
I have researched both theory's on props. The other theory is that the front prop twists the air flow in a helical manner so the rear prop is actually entering the air that is rotating the opposite direction thus acting like a heavier pitch. Lots of theory involved and the distance between the front and rear props also comes into the factoring. Trouble is that there are not a lot of options in the tractor/pusher in a 3 blade configuration to test with...
09-22-2015, 06:00 AM
#66
My Feedback: (43)
Yeah I had read that too.
The pattern guys look for the utmost in efficiency and custom made many props finding that sweet spot in pitch differential. Of course they were using two blade props which may present a whole new set of variables.
I agree that the 3 blade pusher prop selection is poor at best.
I had considered making a modular style like the Zinger but using Xoar blades since the Zingers have always been on the low end of the performance scale.
The pattern guys look for the utmost in efficiency and custom made many props finding that sweet spot in pitch differential. Of course they were using two blade props which may present a whole new set of variables.
I agree that the 3 blade pusher prop selection is poor at best.
I had considered making a modular style like the Zinger but using Xoar blades since the Zingers have always been on the low end of the performance scale.
09-22-2015, 06:08 AM
#67
I agree on the Zinger being pretty low on the efficiency scale..lol. However it works well for me because it allows me to run a scale appearing diameter whereas if I were using a very good prop I would be forced to run a considerably smaller blade which would detract from the appearance to me..To me the thing that stood out on the Red Baron was the massive prop system and my goal was to replicate that first impression...
Last edited by TheRickster; 09-22-2015 at 06:14 AM.
09-22-2015, 06:14 AM
#68
My Feedback: (43)
You should contact xoar directly. I know that they have done custom sized tractor three blades for guys. Maybe they can do a pusher three blade to your specs.
Now you have my mind turning about doing a Miss Ashley II using my fuse and a scratch building a set of Lear Jet wings and tail like she had.
Now you have my mind turning about doing a Miss Ashley II using my fuse and a scratch building a set of Lear Jet wings and tail like she had.
