twn Chen's blog View Details
Posted by twn Chen | Jul 13, 2012 @ 10:10 PM | 6,858 Views
I decided to scratch build this Alula from 3mm depron sheets in last summer. In last July I saw the thread talking about the Alula sold by Dream Flight, it was a side arm launch glider or slope glider actually, it was made of EPP totally. EPP foam is far expensive than depron sheets in Taiwan, and EPP is also hard to be carved manually, so I decided to apply depron sheets instead. Adding clear tapes and with some reinforcements depron sheets can make it stronger than what it is, though it can not be as tough as EPP but what I need is light weight and ease. I think applying depron sheets and EPS foams is still the good way to go when building light electric airplanes. I applied balsa sheets quite a lot when I built glow engine birds before.

Using the said setup with good throttle management this Alula could have 12 more minutes flight duration if it's not too windy. The rest Voltage each cell was about 3.90V right after landing if I applied 50 - 60% throttle more in the air. It could penetrate winds with such throttle, it could fly better in winds if I apply more throttle.

It's very pitch sensitive, I applied dual rates 40 - 60% on its elevator on calm days, while 35 - 50% when it's windy. And the inner hole on both servo arms, while the second outer hole on both control horns. I noticed that the online manual of Alula recommended applying 3mm each way only. While mine is 5mm in high rate. I use low rate mostly, but high rate is required if I want to fly some aerobatics.