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Foam Board SR-71 Twin 50mm EDF(?)
- Thread starter Horseman3381
- Start date
Ok, this is my new favorite thread. A foamboard Blackbird, AND personal stories of dads who were trained by Yeager and people who met him?!? I’ve got my eye on you. 😜
For the prop situation, please feel free to scale the duct to fit 2” props, as they’re far more available. I went with 1.9” because they were on sale (major discount), but in hindsight I probably should’ve gone with 2”. 😆
If you aren’t comfortable tweaking the duct, I’ll see what I can do about uploading one that works with 2” props this week. 😉
Keep up the great work, this is awesome!! I’m so proud that my crazy BUFF project prompted you to try one of your own! Can’t wait to see it fly!
~ Ben
For the prop situation, please feel free to scale the duct to fit 2” props, as they’re far more available. I went with 1.9” because they were on sale (major discount), but in hindsight I probably should’ve gone with 2”. 😆
If you aren’t comfortable tweaking the duct, I’ll see what I can do about uploading one that works with 2” props this week. 😉
Keep up the great work, this is awesome!! I’m so proud that my crazy BUFF project prompted you to try one of your own! Can’t wait to see it fly!
~ Ben
Maybe mechanics like this would work? Simple, single servo in the fuse operates both. Would need thick wire like the large landing gear wire.
Should even be able to offset throw by the angle of the wire by going off parallel like in my crude drawing.
Would require something stronger then foam in the pylon to keep that C bend wire in place where it all pivots though.
Should even be able to offset throw by the angle of the wire by going off parallel like in my crude drawing.
Would require something stronger then foam in the pylon to keep that C bend wire in place where it all pivots though.
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I was really excited when I saw you were doing an "EDF" B-52. I thought the idea of building an edf using a standard quad motor was great. Even though it has less thrust than a standard EDF, it also needs 1/4 of the battery. If I was to use true 50mm EDF's on this plane would need two 3s 2200mah instead of a single 3s or 4s 850mah. That would truly make it a flying brick.
I hadn't even considered scaling up to 2". I could scale it up in the slicing software easily, but the bolt holes would be a little off (not enough to really matter). I do all of my 3D modeling in AutoCAD, and it can export .STL files, but not import them. If you are going to do an updated file for 2" that would be awesome, otherwise if you have the base file available I could tweak it easily myself.
This is how I had initially envision the rudders working, and may give it a try. I had initially dismissed this option because I had convinced myself it would ruin the look of the plane. But I may rig this up at some point to see how it looks. If every thing is painted black it may not be that noticeable. A bonus to this setup is that it would allow the plane to stay on a 6 channel receiver.
I hadn't even considered scaling up to 2". I could scale it up in the slicing software easily, but the bolt holes would be a little off (not enough to really matter). I do all of my 3D modeling in AutoCAD, and it can export .STL files, but not import them. If you are going to do an updated file for 2" that would be awesome, otherwise if you have the base file available I could tweak it easily myself.
This is how I had initially envision the rudders working, and may give it a try. I had initially dismissed this option because I had convinced myself it would ruin the look of the plane. But I may rig this up at some point to see how it looks. If every thing is painted black it may not be that noticeable. A bonus to this setup is that it would allow the plane to stay on a 6 channel receiver.
I had intended to run each control surface on of it's own channel, but after you said this I was looking at the plane and realized if I were to spin the inboard servos 180 degrees I would be able to Y the left 2 servos and right 2 together. Good thing to note for when I update the plans and build version 2. I will probably set up differential thrust on the plane since I have the extra channel for it.
That would be awesome, I appreciate it. I got the motors and ESC's in the mail yesterday. When I was assembling things last night I realized that even thought the props I ordered said 1.9" and are labeled so on the bag, in reality they are 2". So I had to sand them down to fit in the mount. Balancing a 5 blade prop is much harder than a 2 blade.
That would be awesome, I appreciate it. I got the motors and ESC's in the mail yesterday. When I was assembling things last night I realized that even thought the props I ordered said 1.9" and are labeled so on the bag, in reality they are 2". So I had to sand them down to fit in the mount. Balancing a 5 blade prop is much harder than a 2 blade.
UPDATED! I just uploaded an update to the 3D printed EDF duct: https://forum.flitetest.com/index.php?resources/3d-printed-edf-duct-1106-gremlin-motor.46/
Now sized to work with 2" props, and maintains the same motor mount holes.
Now sized to work with 2" props, and maintains the same motor mount holes.
This is awesome! I'm bummed I just discovered it now...
Have you considered just doing twin pushrods for the rudders? A single servo in the fuselage with two thin pushrods guided by zip ties, one to each rudder? It'd be simple and lightweight. It would be asymmetrical, one pushrod would go to the outside of one rudder while the other would go to the inside of the other.
Have you considered just doing twin pushrods for the rudders? A single servo in the fuselage with two thin pushrods guided by zip ties, one to each rudder? It'd be simple and lightweight. It would be asymmetrical, one pushrod would go to the outside of one rudder while the other would go to the inside of the other.
This is great. I'm going to get some of these printed off so I can use them in the Version 2.
I had thought of something similar to this, but think it may ruin the look of the plane. I will probably try it at some point.
I had the plane all together and ready to do a test flight this past weekend, however I ran into a problem. When I plugged the battery in to test the electronics (I had done everything independently with a servo tester prior to this) one of the ESC's cough fire, and the motor it was connected too has melted some so it no longer spins.
When connecting the 2 ESC's to the receiver I made sure to pull one of the red wires to not have doubled up BEC's. I'm not sure what happened, but I have ordered another Motor and ESC. Hopefully they come soon and I can get Version 2 built and test flown in the next 2-3 weeks.
I had thought of something similar to this, but think it may ruin the look of the plane. I will probably try it at some point.
I had the plane all together and ready to do a test flight this past weekend, however I ran into a problem. When I plugged the battery in to test the electronics (I had done everything independently with a servo tester prior to this) one of the ESC's cough fire, and the motor it was connected too has melted some so it no longer spins.
When connecting the 2 ESC's to the receiver I made sure to pull one of the red wires to not have doubled up BEC's. I'm not sure what happened, but I have ordered another Motor and ESC. Hopefully they come soon and I can get Version 2 built and test flown in the next 2-3 weeks.
I wonder if a screw was too long and shorted the coil in the motor.... (I "have a friend" who might have ruined a motor or two by doing that...) 