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May 27, 2014, 02:45 PM
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Build Log

J-Power A-10 Thunderbolt Twin 64mm EDF (49.2")




Flight Pack: Admiral 3S 3700mah 40C
Flight Pack: Admiral 4S 3000mah 35C

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Last edited by peterswolf; Aug 22, 2014 at 09:10 AM. Reason: Updated flight pack information
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May 27, 2014, 03:00 PM
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So I finally decided to start the build on this one. It's mostly a glue together, so this one will take a few days I imagine letting the glue cure properly. For starters I got all the parts out and dry fit everything, Definitely some wiggle room so I'll be needing some gap filling glue... I immediately replaced the elevator servo with a stronger metal gear one, and glued it in place after attaching the push rod through the rear exit hole. I glued the vertical stabs on using foam safe CA, and assembled the main part of the tail section using gorilla glue for maximum strength.
May 28, 2014, 01:58 PM
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Ok, a few updates. I did a lot of work with gorilla glue in the last 24 hours. I reinforced the elevator joiner bar with gorilla glue so that the two elevator surfaces will function equally. I attached the tail section to the main fuselage by inserting two carbon fiber rods and coating them with gorilla glue, as well as a small layer of gorilla glue on the mating surfaces. I added in a carbon fiber tube where the elevator pushrod comes out to allow the pushrod to move more freely instead of rubbing the foam and paint on the plane. And then the big trick. The main wing, when dry held together had lots of gaps... I needed the bond to be strong. So I did the glue in several stages. First I took some wax paper and tape and covered the areas of the fuselage where the main wing attaches so that no excess glue would get in contact. I then put some gorilla glue in just the front portion of the wing. I mounted the wing onto the plane and waited for the gorilla glue to dry... Once dry I removed the wing carefully incase anything did bond to the fuselage, but nothing did so all ok. I repeated this step now a couple of times doing the remainder of the seam where the wings join until it was all full with gorilla glue. I also placed the included carbon fiber rod into the wing slot and gorilla glued that in place as well. This all worked perfectly. The main wing now has a solid center join. You can see in the pictures how the normal gorilla glue bubbles up. This will be cleaned up once I finish assembly easily with a Dremel and some sand paper. When you first apply gorilla glue, I found that if you wipe away excess right away you are ok, but once it starts to bubble up you can press it down a bit, anything you can't press down, just wait until drying is complete then it is much easier to just cut off cleanly. If you try to rip off while it's still drying sometimes you can create more of a problem.
May 28, 2014, 02:44 PM
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A few more updates today. I got the nacelles ready to be installed onto the fuselage, I zip tied the leads together to keep things in place. I will also be using some 3M double sided tape (the outdoor strength version) along the frame to secure it to the fuse. Additionally I will also tape down the elevator servo lead so that it is kept away from the heat of the ESCs. You will also notice in my pictures two square holes in the bottom of the fuselage. I added those in for cooling. Since I removed the nose gear door earlier it will no allow air to come through the fuselage, so this is the exit holes for that intake. I mounted the RX up in the front just behind the cockpit area for better access. I had to add some servo extensions out of my parts bin to make this happen. My HobbyKing metal gear servo was erratic at best, so I replaced it with a ParkZone digital metal gear servo I had laying around, much better now Getting close to complete, I need to hurry up because I have the new ParkZone Sport Cub arriving tomorrow!
May 28, 2014, 08:02 PM
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...and assembly is complete. I used 3m outdoor double sided tape on both the seam for the engine nacelles and the main wing. Both are on pretty solid. Everything wired up and functioning good, of course the fans could use some balancing. I didn't install the ordinance yet as I want to see how it flies without it first. Hopefully over the weekend I should get the Dremel out and cleanup my excess glue and perhaps have a go at balancing the fans. I may also add a carbon fiber spar on the horizontal stab as xplaneguy did, https://www.rcgroups.com/forums/show....php?t=1318942, it seems like a pretty good idea!
Jul 18, 2014, 09:46 AM
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Maiden Flight


Finally I was able to maiden this one today. Got up early this morning to beat the winds. My AUW is around 1400grams and my thrust was roughly checked at 840grams so close to 2 to 3 thrust to weight ratio. Enough for this wing type to fly provided a long enough take off roll. Running an Admiral 3S 3700mah she balances out perfectly. Take of was easy, I use most of the runway but she went up just fine. Once in the air and the gear retracted she flew great, a little bit of trim was required but she held fine. Flying 3/4 throttle mostly she was slower in the air than most jets but manageable. She can glide pretty good, and it took some pressure to get her to come down to land. The flight was uneventful she did exactly what I asked of her, and it was easy to keep her speed up in the bank and yank turns. Landing was a bit tricky since she likes to glide so much. Once I got her on the ground, one of the retracts immediately pulled out of the plane causing a wing to drag and then pop the nose gear out of place as well. No damage at all other than some scrap on the wingtip, the retract mounts came clean off the foam. At the factory they were glued on top of the paint, so ya that would explain why it popped out so easily!!! I will be sanding the paint off and putting the mounts back in place using gorilla glue. Flight time was about 3 minutes, coming down with about 3.90 volts in each cell. Good maiden!!
Aug 21, 2014, 01:45 PM
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Ok so I decided today to try running on 4S on the bench, using a watt meter. I was happy to find that I stayed under max amps during WOT. What I did notice is that my thrust is now up to 1283 grams!!! I'm close to 1:1, how sweet is that?! So with this extra thrust, and NO added weight as my 4S 3000 weighs the same as the 3S 3700, I decided to upgrade the struts to some shock absorbing ones. That should help on my landings. I made sure to keep a slight up attitude on the plane so the shock on the front won't prevent it from taking off. I also plan to get some hinge tape on the control surfaces just to be safe.
Aug 22, 2014, 09:09 AM
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Ok so I flew the A-10 twice this morning on 4S 3000 packs. It flew much better and took off in less than half of the runway! The new shock absorbing struts where great, I was able to cut the throttle for landing and glide her in no problems at all. Now the only issues I have, the fans really need to be balanced better, as well the ESCs are getting quite warm as there is barely any cooling in the back portion of the fuse. I think the "best" idea would be to mount the ESCs so they are exposed to the outside for ultimate cooling. So, now the question is, as I'm moving in half a year and won't be taking this one with me, do I bother with the mods or let someone else have a go at this airframe who might have more experience with EDFs...


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