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Revenant Mk IV - Fiberglass over 3D Printed Foam

localfiend

I like 3D printers...
Mentor
#1
I've got a thread for the printed design3D Printing section of RC Groups. However, I don't want to muck it up with what I'd like to attempt with this first prototype. I've learned all I can from it, and rather than trash it, I'd like to try and make it nice. It's got a few dings, but doesn't need to be scrapped. Also, I'm no fiberglass expert, and I know we have quite a few very good ones over here. I'm also starting a thread identical to this one, in the Scale Scratchbuild section of RC Groups for those interested.

3D Printed foam (LW-PLA from Colorfabb) has finally allowed for a printed design to be able to bear the weight of a fiberglass skin. I'm hoping to gain durability, and a really nice surface to paint the plane up nice. In the attached images below, the white plane is the real one, and the rest are renders of what I'd like my plane to look like with paint.

I've gotten a few flights out the plane, but thanks to some technical issues with a locked up retract, I've pulled the landing gear out of it. I will seal up the gear doors, and just have this thing as a belly lander. That gives me even more weight wiggle room. The wingspan is 54" with 520.7 square inches of wing area. I think without the retracts, my cubic wing loading is around an 8. Not much will change on the base airfram before I start trying to cover it, but I may increase the area of the upper vertical stabilizer a bit, as well as install outer wings with wider ailerons (elevons in this case).

So, I've got a bunch of 1.4 oz fiberglass cloth, enough to cover several planes. I've used it once before on a foamboard XF5U with polycrylic as a medium. This time around I've got some Fibreglast System 2000 epoxy with 60 minute pot life hardener. I've also got some micro balloons if need any filler. There are a couple damaged spots on the underside that will need reinforcement and filler. This prototype was only meant for geared takeoffs, and the spots where it's easiest to grip underneath will need some beefing up.

This foam stuff hides layer lines pretty well, but they are still there, more in some spots than others. It's sands nicely enough though, so I will get to work on that. I'm wondering if I should try and do a filler coat before adding the actual glass and epoxy.

Anyone know if I could get away with WBPU and talc, or the microballoons as a base? Or will I have adhesion problems later when it comes time for glass and epoxy? WBPU is just so nice to work with.

Mk IV Revenant 1.png


Mk IV Revenant 2.png


20200204_095923.jpg


Mk IV Revenant 3.png

Mk IV Revenant 4.png

Mk IV Revenant 5.png
 

Figure9

Well-known member
#2
I've got a thread for the printed design3D Printing section of RC Groups. However, I don't want to muck it up with what I'd like to attempt with this first prototype. I've learned all I can from it, and rather than trash it, I'd like to try and make it nice. It's got a few dings, but doesn't need to be scrapped. Also, I'm no fiberglass expert, and I know we have quite a few very good ones over here. I'm also starting a thread identical to this one, in the Scale Scratchbuild section of RC Groups for those interested.

3D Printed foam (LW-PLA from Colorfabb) has finally allowed for a printed design to be able to bear the weight of a fiberglass skin. I'm hoping to gain durability, and a really nice surface to paint the plane up nice. In the attached images below, the white plane is the real one, and the rest are renders of what I'd like my plane to look like with paint.

I've gotten a few flights out the plane, but thanks to some technical issues with a locked up retract, I've pulled the landing gear out of it. I will seal up the gear doors, and just have this thing as a belly lander. That gives me even more weight wiggle room. The wingspan is 54" with 520.7 square inches of wing area. I think without the retracts, my cubic wing loading is around an 8. Not much will change on the base airfram before I start trying to cover it, but I may increase the area of the upper vertical stabilizer a bit, as well as install outer wings with wider ailerons (elevons in this case).

So, I've got a bunch of 1.4 oz fiberglass cloth, enough to cover several planes. I've used it once before on a foamboard XF5U with polycrylic as a medium. This time around I've got some Fibreglast System 2000 epoxy with 60 minute pot life hardener. I've also got some micro balloons if need any filler. There are a couple damaged spots on the underside that will need reinforcement and filler. This prototype was only meant for geared takeoffs, and the spots where it's easiest to grip underneath will need some beefing up.

This foam stuff hides layer lines pretty well, but they are still there, more in some spots than others. It's sands nicely enough though, so I will get to work on that. I'm wondering if I should try and do a filler coat before adding the actual glass and epoxy.

Anyone know if I could get away with WBPU and talc, or the microballoons as a base? Or will I have adhesion problems later when it comes time for glass and epoxy? WBPU is just so nice to work with.

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WOW!
 

localfiend

I like 3D printers...
Mentor
#5
I'm guessing they're 2306/2400s
Yeah, those are the ones. Went really light for the prototype. Also, those motors put out so much power I'm probably at 2 to 1 thrust to weight. Once I get the fiberglass on, I'll probably beef up the power system for more speed.
 

Tench745

Well-known member
#6
I'm no expert, but 1.4oz cloth seems unnecesarily heavy for something that already has a pretty good surface finish. You'll have to add quite a bit of filler (relatively speaking) to fill out the weave of the cloth.
 

FoamyDM

Building Fool-Flying Noob
#7
@localfiend are you gonna make a DTFB version, or just keep us non-3d printing fools in suspense.
or should one of us eyeball the thing, and put one together.
I can't get over how amazing this looks.
 

FoamyDM

Building Fool-Flying Noob
#8
taken from the the RCgroups thread:
Quick Specs (Subject to Change):

54" Wingspan
520.7 Square Inches Wing Area
WCL of 9.6ish with retracts, oleos, and gear doors. Belly lander variant should be around 8.
8mm Carbon Arrow spars throughout
Removable outer wings
4x possibly 5x 9g digital metal gear servos
2x 50a ESC's
2x 2306 2400kv Race Quad Motors


because I like to go to one spot for my inspiration.
 
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localfiend

I like 3D printers...
Mentor
#9
I'm no expert, but 1.4oz cloth seems unnecesarily heavy for something that already has a pretty good surface finish. You'll have to add quite a bit of filler (relatively speaking) to fill out the weave of the cloth.
Its mostly just what I've got on hand. I do have a bit of 3/4 oz cloth as well. Probably not enough for the whole plane.

I bugged Josh Orchard, and Dan Crews last night a bit about this. Neither one has ever tried using WBPU and epoxy on the same plane, so I'm going to be doing some tests. I'll probably print new wings with bigger ailerons, so the old ones can be test pieces. I could compare weights between the two.

@localfiend are you gonna make a DTFB version, or just keep us non-3d printing fools in suspense.
or should one of us eyeball the thing, and put one together.
I can't get over how amazing this looks.
I've got a rough outline of a DTF version drawn up. Still waffling back and forth on how to handle the curved wings. May just go with a few segments, and if that's too ugly, I'll have to make the leading edge more complex. Straight sweep would still look cool as well. Most of the curves on this thing will not translate easily to foamboard, but should still be able to get a cool looking plane out of it.