Earlier this year in April, I designed and built my favorite plane I have. Keep in mind I have a growing collection of 19+, so that's saying something. It was a glider - I called it the Galaxy, for its immense wingspan of 7.5 ft./2286 mm. It had a length of 5 ft./1524 mm. It weighed roughly 2.2 lbs./1 kg, and was easily flown with a Power Pack C or equivalent. It could have flown with Power Pack B, but it was difficult. On either motor, a 3s 2200 mAh battery balanced perfectly. While these are nice specs, the true marvel of this plane was in it's gliding ratio. It was the floatiest plane I have seen. While I don't have a good way to measure glide ratio, I compared it to the FT Explorer with the glider wing. The Galaxy could glide for roughly 5 times the distance of the Explorer with the Explorer at its lightest. I could fly nearly vertical with my Power Pack C to about 400 ft./120 m, then cut the motor and glide down for a solid 4 minutes. I would then repeat the process over and over until the battery died.
I didn't have much skill when it came to thermalling. However, one day I was out flying, and I noticed vultures circling overhead. I decided I could use them to tell where the updrafts were. So, I motored up to about the height of the vultures, and cut the throttle. The plane was flying for about 2 minutes without losing altitude, but then it started rising. After little more that 5 minutes, my plane was just big enough to see. I had to dive for a while to bring it closer to me. A picture of it can be seen below.
Now, a shrewd reader might notice that I only used past tense. There is a story behind that.
Many people were at Flite Fest 2016, and along with them many planes. I was one of those people and the Galaxy V1 was one of those planes. I being my favorite plane, and a self-designed plane at that, I had made up my mind that I was going to bring it.
My family and I arrived to Furey Field on Friday morning. I had lots of fun the first day, as did my family. I joined the FT Stem high school challenge (my team's planes didn't fly - our payload plane's wings folded, bringing the massive wing that flew it up to drop height down with it), flew in many combats, and got a plane signed a few times. That night, I contentedly fell asleep to the sound of night flyers buzzing in the distance
I woke up on Saturday readier than ever. I did some browsing and casual flying, as well as asking about other people's planes. Really cool stuff. Early afternoon, I brought out a monster of mine - A 200% Galaxy Glider. It has a fifteen foot winspan and is ten feet long, with a two foot chord. I can write an article about that later if needed. Anyways, that was a screaming success. Some pictures are below:
Then came the Galaxy V1's last hours: The World Record Attempt for Most Planes in the Air. After the pilot meeting, I went over to thr sign-up booth for pilots. I chose the Galaxy (my favorite plane) on the grounds that it is huge, so it would be easy to tell apart from all the other planes. Also, I chose it because if I did lose track of it, it wouldn't crash because of its tendencies to fly straight and level with no pilot inputs. So, I got my registry flag and got ready to fly.
The time came. I got my dad to spot me and help me find it if I lost it in the swarm. The announcer called my group, group four, to take off first. I chucked my plane and climbed to about 400 feet. Groups three, two, and one took off, with my dad distracting me from flying with his incessant comments about how planes were just dropping out of the sky like flies (it was quite funny actually). I digress. Soon the announcer was counting down until the minute would start for the record attempt. 3...2...1... BEEEEEEEEEP. I decided to fly steady and slow so I didn't crash into any other planes.
THUMP! Time seemed to slow down as I helplessly saw a red race wing doing a loop right underneath me...wait no...at me...wait, it's in me! The race wing slammed into my wing on the center section at the peak of it's loop at high speed, leaving a three inch gash in my wing and instantly stopping it mid air. But that wasn't the problem. I could glide down to a safe landing with the rest of my wing and salvage the fuselage. At this point I was about 450 feet up, so the inevitable forced stall would have been easiy recoverable. The issue was that the impact from the race wing had twisted the wing, which popped the rubber band holding my wing to my fuselage. I was lost for words. All I said was, "I'm hit, I'm hit, Dad, I got hit," as I watched the fuselage and tail plummet nose-first to the earth like an oversized dart. It seemed like it took hours for my most beloved, best plane to fall to the earth. After it had disappeared into the soy, I looked back up to see my wing fluttering down to the earth. And quite ironically, it was very graceful, just turning over itself slowly as it glided down.
My dad handed the flag in to the coordinators of the record for counting purposes. Soon, all the planes were on the ground, whether intact and ready to fly again or decimated like mine. One actually landed on me. But they blew the whistle to retrieve the planes, and my dad and I trekked out into the soy to look around for the plane. I found the fuselage pretty quickly, and my dad had similar luck with the wing. Here is some of the wreckage:
When I found the fuselage in the soy, I wanted to check to make sure I had everything. The motor was there. Check. The ESC was there. Check. My reciever and two servos were there. Triple Check. My battery voltage alarm was there. Check. But...where was the battery? I called out to my dad that I couldn't find the battery. We spent what seemed like hours trudging in circles in the soy, looking for my lost battery. Soon, two kids about two or three years younger that me came out to help me look for it. They had let me borrow their glue gun to glue on two popsicle sticks to fix my now dead plane. I think it was Mr. Bixler's son Michael and a friend of his. Anyways, we couldn;t find the battery after a while searching. Meanwhile, I still had to make the return walk of shame with my foam noodle. And when I say noodle, I mean noodle. The fuselage was broken and bent in so many pieces that it flopped whenever I carried it. Some pictures are below:
Here is the front of the fuselage where the power pod slides in. The foam came unglued from itself and as you can see totaly messed up the nose.
In the above two pictures you can see the area right behind the power pod, one of the most stressed areas in the crash. When I found the plane, the walls of the fuselage were very much spread apart, and the fuselage was folded at a 45ish degree angle. You can also see the cavity that the BBQ skewer which held trhe power pod in carved.
Believe it or not, this was one of the worst damages to the fuselage. As you can see, the foam literally ripped itself apart. On both sides of te fuselage. The only thing holding it together now is the layer of paper on top of the fuselage. Behind this portion, the tail is intact. However, the front is completely dead.
This is the brunt of the damage, There are wrinkles adn bends where the foam was stressed on other parts, but the above places are where most of the damage is.
For the rest of Flite Fest, I was really frustrated that my favorite glider had crashed. I had plenty of other planes to fly, but still, I was sad. I had been thinking for about 4 weeks prior to FliteFest about building a second version. Even though the first was a great glider, there were some wonky characteristics. It would nose-up badly when given lots of throttle (which I now know was a CG issue) and the tail had horrible torquing and twisting problems. Also, right behind where the wing attached, the fuselage was bending downwards from the weight of the tail and any up elevator inputs. The walls of the fuselage were bending inwards right under the CG from launching it (Keep in mind the plane is over 2 lbs/1 kg). The wing had no issues. The fusselage was the problem.
This is when the birth of...wait for it...the Galaxy V2 comes! I rebuilt the wing with absolutely no changes from the first. The tail is the same way. However, the fuselage has undergone a total remodel. A picture of V2 can be seen below:
If you comare the picturee from V1 to V2, there are no changes apparent at first glance. The wing is the same, and the tail is the same, which draw the eyes the most. And while the googley eyes are added on, the structural fuselage changes cannot be seen in this picture.
Meanwhile, it glides just as well as the first one. I don't have a radar gun, but I was doing some tests and while gliding, I can just be in a slow run to keep up with it. My estimate would put this plane at around 7-9 mph/11.25-14.5 kph gliding, like the first one. Under power, I believe it is around 13-17 mph/20-27 kph. The added reinforcements only add another 49 grams to the total flying weight. The same 7.5 ft./2286 mm plane can be flown off of Power Pack C with a 10 inch/254 mm prop and a 1300 mAh 3s battery. With this motor, it can go nearly vertical, and has almost a 1:1 thrust to weight ratio. The maiden flight is below:
On the second flight, I wanted to see how long I could fly in one flight. I took my two biggest batteries (at the time), two 2200 mAh 3s, and I hooked them up in parallel and positioned them to get the right CG. I flew for 1 hour and 28 minutes, flying at the same throttle setting for the entire flight, and going in a wide, gentle oval. I had set my voltage alarms to beep at 3.5 volts, so I could have flown longer if I wanted to drain the batteries lower than that. However, I never go below 3.5 volts on normal flights. I recently got a couple new 5200 mAh 3s batteries, so I want to test them out with only one on the plane and with both in parallel. With one, the estimated flight time is 1 hour and 44 minutes, and with both, it should be around 3 hours and 18 minutes. I'll need to bring refreshments with me. A video of the second flight can be seen below:
Below are picture of the construction of the plane. On my article for the first version, I asked for help on some of the issues I was having. I used a lot of the suggestions on this version., such as closing off the bottom of the fuselage as suggested by Larry Laitner, or cross bracing as suggested by Mostly Harmless. Thank You!
Above is the right section of the wing. It is built the same as the other two sections, except it has a section cut out of it for the undercambered wingtips. On the top section, run a popsicle stick or BBQ skewer through the score cuts to leave a cavity. On the lower score cut, where the wing folds over, do a double bevel on both sides of the cut.
Above is the joint that runs parallel to the leading edge of the wing. The top section of the wing is 12 in./30.5 cm, and the bottom section is 11 in./27.9 cm, so the 20 in./50.8 cm width of the foam doesn't cut it. A 3 in/7.6 cm extension needs to be added to the wing. To do this, line up the extension with the rest of the wing. Put packing tape on one side, then flip it over. Lift up the wing to open up the cavity, and put a thick bead of hot glue down the middle. Lay the wing flat, and use a piece of foam to wipe off the excess glue. When it is cool, put a strip of packing tape over the side that isn't taped yet.
Once all the wing sections have been double bevelled and gotten their extensions, then do the same tape/glue/tape techinque to glue the BOTTOM sections of the wing together. I repeat, only the BOTTOM. Glueing the top right now will not only make you cry when you try to fold over the wing, but it will also block it form being able to have any polyhedral.
Here are all the wing spars drawn out and ready for the razor blade.
Here are the wing spars cut out and glued. The shorter ones are for the outer two sections of the wing, and the longer and wider one is for the inside. Glue them on to the wing lined up with the first crease line from the fold cut
Here you can sorta see where to glue the spars. Glue it in between the two crease cuts, but right up against the one closest to the leading edge of the wing. Make sure to leave enough space to put glue in the crease cuts.
MAKE SURE YOU ONLY DO ONE THIRD OF THE WING AT A TIME!!!! Start with the center section, then do the two outer ones.
The wing is a bit large to fold over in one shot, so I break it up into different "fold groups." The first time, I only put glue in the crease ut closest to the leading edge, then fold over the wing and position the spar and middle section of the wing level to the table. On smaller planes this is not necessary, but since there is a greater distance in between the supports I put glue there. It also makes the next step much easier
On the second round, I put glue in the leading edge of the wing, and the spar. Put a bead of glue in the leading edge before you put the beads on the two walls of the spar. That makes sure that the spar sits flat on the wing.
After the first two steps, all you should have it the back flap of the wing not glued down. To do this, flip the wing vertically so that the leading edge is down and the trailing edge faces up. Then, put a bead of glue on the hinge line, flip the wing flat again, and put glue on the bottom panel of the wing where the top flap touches it.
Make sure the undercambered wingtips get lots of extra support during all these steps.
I don't have any pictures of this because it is probably the most important part of the wing and required all my hands. At the joint where the wings break for the polyhedral, take a popsicle stick/BBQ skewer and drive it through the wing when it is flat to spread it apart. There will need to be a sizeable cavity here to let the wing fold up comfortably. Keep using the nine inch spacer under the wingtips to gauge how far you need to go before you can glue. The outer sections of the wing should be able to fold up comfortably, but with a little resistance. It helps to use a razor blade to shave away bit of the top of the wing to make the cavity. Also, for aesthetics and structure, try not to have too many gaps when you fold up the outer sections. Once you are happy with the fit, pick up the wing at the break to open up the cavity. Line all the foam that toucheswith glue. A lot of glue. This is the only place where I suggest you go pretty heavy handed with the glue. When you have sufficient glue, lay the center section flat, and lift the outer section up to put the nine inch spacer in right at the tip of the wing. Wipe off the excess. I suggest you have a weight hand to put on the center section, because it will want to spring up a bit. Let the joint sit for a good 3-4 minutes before repeating on the other side. When done with each side, put tape all along the joint you just glued. Make sure the tape is secure.
For the fuselage, dig the foam out of the cavities where the walls fold up. Do not glue the walls yet! Use the same tape-glue-tape technique used on the wing to glue only the center section of the fuselage together, as seen above. You might notice there is a small opening between the walls of both sections of the fuselage - this is so they lay perfectly 180° when you fold up the walls.
Next, fold up the FRONT walls of the fuselage only, in a B fold. The front is the half that is the same size for it's entire length, and the rear is the one that tapers.
Next, fold up the rear walls of the fuselage, in a B fold. Make sure to put glue on both the bottom section and the front walls of the fuselage. After this is done, put a piece of tape on the glue joints connecting the front and back sections, both inside the fuselage and out.
For the tail, cut the red lines on the planes as your score cuts, then cut a bevel on the control surface. I highly recommend putting a bead of glue in the hinge and then wiping it out, because this is a plane that won't be breaking after a couple weekends. I had my first version for about five months, and I have had my second for about 3 now.
The next part is pretty straighforward. Apply glue on the bottom of the vertical stabilizer, then slip it into the tabs on the horizontal stabilizer. Use a square to keep it 90°. After the initial glue is dry, put two more beads on both sides and wipe away the excess. Make sure the control surfaces won't bind during all this.
Use two BBQ skewers and stick them through the holes on the horizontal stabilizers. Glue them into the hole on the vertical stabilizer, then glue them onto the horizontal one. Make sure all is square during this.
Attaching the tail to the fuselage is as easy as pie. Just dry fit the tabs on the tail in the tabs on the fuselage, and make a sligth crease with your fingernail where beginning of the horizonatl stabilizer is. Then, remove the tail, apply glue on the fuselage from the crease you just made backwards, and re-insert the tail. Hold square and until the glue is dry.
Afterwards, install the control horns into their respective slots.
Cut slots just in front of the horizontal stabilizer to fit thelinkage wire through.
For the servos, I like to glue them to the fuselage in this orientation, with the wires facing forward. Keep in mind that in this view the top of the fuselage is on the table and the bottom of the fuselage is facing up. Wire length and servo placement isn very particular on this plane, but make sure you have enough room for both servos to lay like this. You can see on the right servo that there is barely enough room for the linkage stopper.
Note: Do not glue in your servos until you have installed the reinforcement straws.
Since the wire is so long, it is pretty easy to bend out of shape. For that reason, I added three coffee stirrers to each wire, which is also easy for its bendyness. One is only on the inside of the fuselage, one is half in, half out, and one is completely outside. Glue them against the nearest wall or foam piece. I like to add these white ones to my planes because they blend in with the foam, making the plane look prettier and neater.
I don't have picture for this, but it's pretty simple: for the pegs on which the wing rubber bands to, just insert and cut two BBQ skewers with about half an inch hanging off of both ends.
Here you can see the bottom of the fuselage pretty well. On the rear portion, simply run two beads of glue on the bottom plate and fit it into place. On the front, make sure that the reinforcement plates are aligned so that most of the cuts nd slots aer towards the rear of the plane, and toward the open end. Glue them flat up against the side walls of the fuselage. Before doing that, I like to glue a popsicle stick overlapping the joint between the two fuselage halves
After this, just glue in the small reinforcement platforms into the slots on the fuselage.
To align the wing, measure the centerline on the top of the fuselage, and measure the centerline of the wing. When you rubber band the wing on, they should align with the wing dead center and square.
These completed picture don't have rubber bands on them - I typically have just two criss-crossing over the wing.
Above are the aforementioned alignment ticks. I like to put a popsicle stick on the rear of the wing to protect the foam from those pesky rubber bands.
Here you can see a better view of what the wing is supposed to look like on the inside. You can see teh spar is right up next to the first wing crease.
The bottom of the fuselage.
Okay, so now we are down to the nitty-gritty.
Wingspan: 88 in./2235 mm
Length: 63.5 in./1613 mm
Weight: With 2200mAh 3s-37.625oz./1068g Dry Weight-25.625oz./858g
Wing Area: 7.5 sq. ft./0.696 sq. m
Wing Loading: 142.4g/sq. ft.
For electronics, I personally use Power Pack C for motor and ESC, with a 10x4.7 propellor amd two 17g Hobbyking servos. However, there are other options. I have flown it with a Power Pack B equivalent, but it does not have much power and I prefer the larger motor. It can be done though. If you are more DIY, then you could use the following:
Battery: 1300mAH 3s - 10,000mAh 3s (2200mAh 3s is ideal)
NOTE: The servos that I use are 17g servos, but they are not sold by Hobbyking anymore. The ones I have listed are the same line and slightly stronger, so they will work well The ones that I have are 2.5kg torque servos.
This is a fantastic glider. It uses 6-6.5 sheets of DTFB, pretty efficient fro such a large plane. I am working on one with a slightly larger wingspan. Anyways, this one is incredible, and iw my favorite plane by a long shot.
You might notice that I am pretty young. This is a bit of a problem with the money situation. So, if anyone is interested in funding me for more projects and gadgets, let me know in the comments! I can set up a Patreon page. It will greatly help me grow my projects to be bigger and better.
If you have any questions, comments, or concerns, let me know!