Flight testing II
After some more testing today incorporating some design changes, I have isolated factors influencing flight performance
- Wing span
- Wing angle
- Head weight
- Folding wing tip
- Fold wing trailing edge
- Cut out plane head
Especially the ones in bold made significant impact on performance. Once this is realised, I spent sometime with my next door neightbour discussing why this is so (who by the way showed me how to fold his 'ultimate paper plane' ; see picture below) .We finally agreed that
- Head weight helps to keep plane head down (lower pitch angle) during flight (too much pitch angle create stalling).
- Folding wing tip helps focus airflow above the wing surface. This in turn increases 'above' wing speed and hence lower 'above' wing air pressure according to Bernoulli's principle
- Folding wing trailing edge up increase climb, whereas fold down makes plane dive. Folding one up and the other one down makes plane turn corners.
Ideally to keep plane aflot, the plane should not climb too much so that stalling occurs. Equally, it should not dive. So to keep plane 'leveled' , different adjustment to the head weight and folding trailing edge is needed. I think this could be a potential source of 'interaction' in Taguchi experiment. Another observation I got from my neighbour's design is plane can go through a series of climb-dive fly patterns to stay in air longer, I have yet to figure out how this happens.
I think these discoveries are good, I feel I finally discovered some significant control factors. Now I need to proceed into my next stage- experimental design, and finding a way to measure time, and find a big space to carry out my experiment.
I have spoke to sport centre and I think I can use the basket ball courst in the moring (730am) during the week. But I still someone to do measuring time for me. I understand everyone will be busy this week with KBAM and PIUSS , is anyone able to help ??
First prototype - Cut plane head; folded wingtip and folded wing trailing edge; paperclip added to head (not visible)
Ray's Flying Champion - My neighbour's ultimate flying champion. According to him this one can fly for ages and ages. It's a very different design with much bigger wing aspect ratio. The head is folded several times to make plan head 'heavy'. Wingtip is 'rolled' instead of folded. Strangely this one has a habit of flying in circles and go through several 'climb dive' patterns.