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Jul 20, 2017, 07:37 AM
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rajazo's Avatar
Thanks a lot for share this info. Looks lot more easier than a vacum former that I found and I never had a clear idea of all the process.
Thanks a lot
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Jul 23, 2017, 08:58 PM
Designer at Heavymetalrc.com
Scalejet757's Avatar
Thread OP

The Build


A couple more parts coming off the printers and laser in the next hour and I'm set to get started on the build. Let's see how far I can get into the night! I'll post steps as I go.. is it possible to build and maiden in 24hrs?
Jul 24, 2017, 06:15 PM
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Scalejet757's Avatar
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Restart


Lastnight, as I was finishing up getting the last few parts made for the airplane, I found that the laser wouldn't cut through the balsa sheet that I was using for the spars and ribs. The laser is fantastic, but a 3500mw is slightly weak on the more dense sheets of balsa. An upgrade is in order However, I elected to use some 6mm gray depron for the ribs in place of the wood. This will be a good trial for an even MORE foamy model. So, now.. I'll restart the timer when I get home tonight or tomorrow morning, and see how far I can get in one swipe with all of the parts ready to go. I can't wait to show you the new features I drew up for the build. Stay tuned
Jul 25, 2017, 01:02 PM
Senile Member
Lnagel's Avatar
Thanks a bunch for posting the files. Here's a photo of the wing tip molds being printed. One question, do you smooth the surface of the molds to rid them of the ribbing that results from the printing process? And, if so, how?

Great job so far,
Larry
Jul 25, 2017, 02:39 PM
Designer at Heavymetalrc.com
Scalejet757's Avatar
Thread OP
Quote:
Originally Posted by Lnagel
Thanks a bunch for posting the files. Here's a photo of the wing tip molds being printed. One question, do you smooth the surface of the molds to rid them of the ribbing that results from the printing process? And, if so, how?

Great job so far,
Larry
Looking great Larry! Yes sir I do. Printing with at least 3 outer perimeters gives you the cushion to sand into the mold enough to get rid of the layers. The higher the resolution of the print, the easier it is to sand. Start lightly with a rough sand paper like a 120 grit to penetrate most of the layers. Then move to something like a 220 and then up to a 320. When the layers are no longer visible, move to a very fine finishing grit. Wet sand works well enough that the part could almost look injection molded upon finishing. You don't have to have THAT nice of finish for vac forming, but you want to make sure the plastic can slide over the surface during the pull. Be sure not to sand to far into the wall, especially if you are using PLA. The extra perimeters allow the heat to absorb into the wall without bringing the PLA to melting point. The Vac process cools the mold to a stable temp pretty much immediately. ABS is easier to sand, and I've never had it collapse because of temperature. You can get away with only 2 perimeters with ABS. Maybe even one. The only problem is, when you attempt to print molds that have a lot of area on the bed, you will get some curling on the edges, which can cause issues if you need accuracy in the part for vac forming. So I use PLA, and put the hard work into the sanding process. After all, you do only have to make these things one time.. and you get what seems like unlimited parts from them.
Aug 02, 2017, 05:28 AM
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Scalejet757's Avatar
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Getting Started On the Fuselage


Alright! Well, I'm finally finding some time to get some build log going! Lasted about an hour taking pictures and fixing files along the way, I did find a couple minor errors in the pieces fitting. So, the foam "dash" bulkheads and firewall, had to be adjusted, along with the wing reinforcement pieces which are glued to the inside of the fuselage under the wing saddle. I also did away with the "notches" on the main bulkheads because I found it just so much easier to just glue em' on. The alignment turned out not so critical. The file downloads on this forum have not been updated just yet.. I will fix them shortly. Good day!
Last edited by Scalejet757; Aug 02, 2017 at 05:35 AM.
Aug 03, 2017, 07:29 PM
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Tail Section


I took a picture of every step during this process to document for any builders and also myself! So there are many. The sticky back paper is a glossy clear label paper by Avery, printed with an inkjet. I also decided to mount the servos as far forward as possible this time, and run carbon push rods. (Later Steps) I'd like to get below the weight of the last model, and see what she can do with the smaller 180 motor at the lighter weight.
Aug 06, 2017, 09:00 AM
Registered User
cbalgra's Avatar
Real nice technique Scalejet. Will have to give it a try.
Aug 06, 2017, 02:40 PM
Designer at Heavymetalrc.com
Scalejet757's Avatar
Thread OP

Side Panel Windows


Thanks! Yes I recommend giving it a try! It's a blast!

For these windows, I do recommend using a thinner and lighter plastic when vac forming. You can get .01" thick sheets from easybuiltmodels.com
Aug 06, 2017, 03:17 PM
Designer at Heavymetalrc.com
Scalejet757's Avatar
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Main Landing Gear


This was easier than I thought it would be. It was also the first attempt at using fully 3d printed struts with wheel pants. BTW.. When you go to print these struts, I would change the infill to "0". No infill! They are pretty strong and maybe a little over kill, so to lighten them up, print them hollow and no supports. I will update the file info.
Last edited by Scalejet757; Aug 06, 2017 at 03:31 PM.
Aug 08, 2017, 03:08 AM
Designer at Heavymetalrc.com
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Reciever, ESC, and Motor


I wanted a better Rx access, and entertained the idea of cutting out a door with hinges and a magnet lock. So I took the impulse and went at it. The door cut from the already built frame, turned out a little junky with pen lines and rough cut edges. So I apologize about that.. but I think I may end up including this in the design patterns from now forward cuz it works so nice! It's definitely optional for those builders that want to take it on and could probably be improved a bit. I'm thinking I may replace the door with a newer and nicer one..but the pics show how it works.
Last edited by Scalejet757; Aug 10, 2017 at 01:11 AM.
Aug 08, 2017, 09:14 PM
Designer at Heavymetalrc.com
Scalejet757's Avatar
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Cowl attach and Fuselage Markings


I discovered on this particular model, that the side markings are strong enough to hold the cowl to the fuse without much wiggle! So.. option- you can leave the hardpoints out, reducing weight a bit, and hold off from punching holes into the cowl, IF you decide to use the markings or even just a clear tape to attach the plastic. I try not to use tape ANYWHERE if possible. It just seems to add to the over all "junky-ness" of the model. The objective of this build was to fake out my brother and show up at the field claiming these were kits I picked up at the hobby store Unfortunately, he found the thread before I could carry out the agenda.
Aug 10, 2017, 12:57 AM
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Scalejet757's Avatar
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Belly Panels, Battery compartment, and Tail Wheel


I should "amend" a couple previous steps as follows- #1 When checking that the cowling and windshield fit over the fire wall.. I suggest moving the next step here, as the first step before fitting the cowl. The lower fuse panel that also plays as the battery compartment panel, should be fitted first before you also fit the cowl and get your hardpoint markings, if that is the rout you're taking. I noticed it was harder for me to get everything to fit together by attaching this later. Oopsy! Everything should fit nice and snug, and be nice and straight.. with a very appealing blend between contours. #2 The Tail Wheel should be taped to the tail end of the fuselage, and inserted into the rudder before gluing the hinges in permanently. I'll edit the previous posts for both of these hopefully before anyone begins construction. Along with the files which need to be updated slightly. (mostly hardware and DXF file)
Last edited by Scalejet757; Aug 10, 2017 at 01:05 AM.
Aug 23, 2017, 07:40 PM
Designer at Heavymetalrc.com
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Thread OP

Wings and Ailerons


This is the "foam" version of the wing, which still includes balsa spars. You can obviously use whatever you like. Carbon rods, foam... whatever. More coming soon. Almost done!


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