Nigel
Moderator
Earlier today, I was lucky enough to get my hands upon an old, possibly competition grade 2 channel glider. It's an old fiberglass fuse, with a balsa wing and V-tail.
No, it was not about to fall over the edge
It came with some surprisingly quick but full size servos, a 72 Mghz receiver, an ancient NiMH pack, and an adjustable tow hook
It measures 59 inches in wingspan (60 inch competition class?) and 33 inches long, AUW is still in flux with new lighter servos and adjusting CG. The V-tail utilizes plywood control horns, and a surprisingly slop-free push rod setup. The hinges are either Blenderm or some similar variant, I'll be replacing it as it has started to lose it's grip at the seams. The fiberglass is also very old - it gives off a plastic-like smell after a clean and has the obvious brown hue.
And now for the scary part: the maiden!
I hadn't actually planned to maiden it at all, but after looking at the electronics and linkages I realized it could quickly be made flyable. I borrowed an ESC to supply 5V for the servos and rx, a 4 channel receiver, and a 2 cell battery. When I modernize the electronics, I plan to most likely use a direct 2S pack with some Bluebird servos.
After hooking up the electronics, I replaced the NiMH pack with a 2s Lipo. As the weight distribution was much more tail-ward, I opted to add a bag of lead shot I carry around into the nose, as well as the pre-existing ballast.
Initial test tosses and chucks went well, but the plane carried some interesting tendencies. Without airspeed that I would gauge to be excessive for its weight, it experienced a bad dutch-roll like oscillation. My pre-existing knowledge with powered ships lead me to believe that it was tail heavy - so I added more and more nose-weight. The plane flew better, but still had some odd tendencies.
Right about now I realize I have no idea what I'm doing
Thankfully, Ed was there to give some advice. Acting upon it, I removed a significant amount of the nose-weight again and again, until I was left with about a third of what I had initially. Surprisingly enough to me, the plane flew better, even though I had significant down trim as well that I removed. As we were removing ballast, I also increased my expo - I believe part of my issue was my instinct to over-control the aircraft along with slow servos and even slower air frame response time. After this, I managed to make a couple patterns around - from just a chuck! This thing would start lifting before it indicated!
A quick launch
Just Chris executing one of his many perfect hand launches
After multiple successful hand launches, we opted to try for a tow. After attaching a soda opener tab onto some string, we tried the first of many tow launches.
Initially, there were many issues. A napkin we had tied into the string to add drag made the ring slip off prematurely, usually before any altitude was gained at all. Secondly, we needed more airspeed than anticipated. Finding the correct tow speed was a challenge as the wind continued to change velocity.
After doing more CG shifting, and moving the tow hook forward, the glider started to gain significant altitude. But, as a relatively new glider pilot, and as my first glider tow, it was not without incident.
On one occasion, the wind gusted right as I was flying up - leading to extreme tension on the line - which then popped off like a rocket. Other times the wind died and lead to weak launches and premature release, and other launches had the line hang on scarily long. A small toss to test CG coupled with a gust also launched the glider with everyone unprepared, however the wind was perfect and the launch continued as normal.
For my first time towing, it was definitely a new challenge. I don't doubt things would've gone differently were it not for the advice of the more experienced pilots. For instance, I had the intuition of pulling back too much during launch - something I quickly discovered that would lead to an uncomfortable situation. After several successful launches, I decided to call it a day before I walked away with splintered fiberglass and balsa. I am quite pleased with how it performed as it was, and can only guess that with better servos, less weight, and more CG optimization that this thing will thermal like crazy.
As a side note, if anyone recognizes this plane it would be greatly appreciated - any concrete data or specs I can get my hands on would benefit the longevity of this glider greatly.
No, it was not about to fall over the edge
It came with some surprisingly quick but full size servos, a 72 Mghz receiver, an ancient NiMH pack, and an adjustable tow hook
It measures 59 inches in wingspan (60 inch competition class?) and 33 inches long, AUW is still in flux with new lighter servos and adjusting CG. The V-tail utilizes plywood control horns, and a surprisingly slop-free push rod setup. The hinges are either Blenderm or some similar variant, I'll be replacing it as it has started to lose it's grip at the seams. The fiberglass is also very old - it gives off a plastic-like smell after a clean and has the obvious brown hue.
And now for the scary part: the maiden!
I hadn't actually planned to maiden it at all, but after looking at the electronics and linkages I realized it could quickly be made flyable. I borrowed an ESC to supply 5V for the servos and rx, a 4 channel receiver, and a 2 cell battery. When I modernize the electronics, I plan to most likely use a direct 2S pack with some Bluebird servos.
After hooking up the electronics, I replaced the NiMH pack with a 2s Lipo. As the weight distribution was much more tail-ward, I opted to add a bag of lead shot I carry around into the nose, as well as the pre-existing ballast.
Initial test tosses and chucks went well, but the plane carried some interesting tendencies. Without airspeed that I would gauge to be excessive for its weight, it experienced a bad dutch-roll like oscillation. My pre-existing knowledge with powered ships lead me to believe that it was tail heavy - so I added more and more nose-weight. The plane flew better, but still had some odd tendencies.
Right about now I realize I have no idea what I'm doing
Thankfully, Ed was there to give some advice. Acting upon it, I removed a significant amount of the nose-weight again and again, until I was left with about a third of what I had initially. Surprisingly enough to me, the plane flew better, even though I had significant down trim as well that I removed. As we were removing ballast, I also increased my expo - I believe part of my issue was my instinct to over-control the aircraft along with slow servos and even slower air frame response time. After this, I managed to make a couple patterns around - from just a chuck! This thing would start lifting before it indicated!
A quick launch
Just Chris executing one of his many perfect hand launches
After multiple successful hand launches, we opted to try for a tow. After attaching a soda opener tab onto some string, we tried the first of many tow launches.
Initially, there were many issues. A napkin we had tied into the string to add drag made the ring slip off prematurely, usually before any altitude was gained at all. Secondly, we needed more airspeed than anticipated. Finding the correct tow speed was a challenge as the wind continued to change velocity.
After doing more CG shifting, and moving the tow hook forward, the glider started to gain significant altitude. But, as a relatively new glider pilot, and as my first glider tow, it was not without incident.
On one occasion, the wind gusted right as I was flying up - leading to extreme tension on the line - which then popped off like a rocket. Other times the wind died and lead to weak launches and premature release, and other launches had the line hang on scarily long. A small toss to test CG coupled with a gust also launched the glider with everyone unprepared, however the wind was perfect and the launch continued as normal.
For my first time towing, it was definitely a new challenge. I don't doubt things would've gone differently were it not for the advice of the more experienced pilots. For instance, I had the intuition of pulling back too much during launch - something I quickly discovered that would lead to an uncomfortable situation. After several successful launches, I decided to call it a day before I walked away with splintered fiberglass and balsa. I am quite pleased with how it performed as it was, and can only guess that with better servos, less weight, and more CG optimization that this thing will thermal like crazy.
As a side note, if anyone recognizes this plane it would be greatly appreciated - any concrete data or specs I can get my hands on would benefit the longevity of this glider greatly.
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