Bravo! I started flying R/C in the 70's and have been away from the hobby for 25 years and just now getting back into the hobby. I am shocked at the sheer number of poorly designed aircraft in the hobby market. We did not have this problem in the 70's through about mid 90's. Without knowing anything about you, you obviously are tied tightly with true aeronautical design principles. You need to put this design into production.........
Of course nowadays with cheap efficiënt power systems (lipo’s and brushless motor’s) there is no need for efficiënt airframes if you only need to fly 10 minutes or less.
@@CrystlizeWorldif you have a remote idea of how many hours go into designing, testing, proving, iterating again, validating, writing instructions, making videos, configuring the build.. etc, properly... Price is ok.
I love the fuselage design! Altough I am not a fan of 3d printed uavs I really liked your design it looks so slick and I might even try 3d printing it on my ender3 v3 se when I have necessary components. Great work you are on my radar now have a nice day!
Awesome build, what a monster! Love the wing bays, such a cool way to make use of the large wing size. The only gripe I have with the design is the fact that it has a non-continuous spar. From a structural point of view, this can be a little precarious. But considering you have an incredibly low wing loading anyways, it's likely not going to be an issue. I would expect you made this design choice because you couldn't source long enough carbon tubes to go the entire span?
Yep! Sourcing carbon fiber tubes longer than 1 meter is not easy, not to mention the shipping costs would likely be ridiculous. The combination of twist and taper in this wing would also make it difficult to do full length spars.
@@gabejanssen4826 Yeah, I usually limit my designs to what I can source without excessive costs like that. I presume you have some downward twist towards the wingtips to prevent tipstalling at high angles of attack?
Yeah, though only a little at about 3 degrees total twist. Elliptical lift distribution is achieved in this design by morphing the airfoil along the span, one of the many unique things 3D printing allows for in wing design.
@@gabejanssen4826 Some classic glider design solve this by inserting one step smaler diameter CF tude, which is also more weight and dimension optimal, since the profile at 1m from the wing root is usualy quite smaller.
Awesome design! I suppose it's around 5A in cruise, good result. Recently I designed similar twin motor plane, very stable scheme(have some videos on my channel. Which wing and tail profiles you have used?
It seems to me that a high efficiency plane should have an inverted V tail. It wouldn’t have the adverse roll in the turns to counteract so it would need less aileron deflection.
That's correct, inverted V-tails are generally superior in terms of flight dynamics. Unfortunately its hard to make a durable inverted V-tail without doing a twin boom design, which would likely introduce more drag. Also, during high efficiency flights you probably aren't doing tight maneuvers frequently enough for adverse roll to have a significant effect on efficiency. Although I could see the affect being more noticeable in gusting winds.
@@gabejanssen4826 It'd still be more drag in absolute terms but you could probably minimize the amount of drag from an inverted V-tail by taking advantage of the ability to print complex curving structural elements. Either by having a smooth fork of the main tail to support the stabilizers, or by curving a single tail upwards like a whales tail to hold the bottoms of the stabilizers above the ground during landings. could even get weird with it and make a three pronged forked fuselage that supports all three points of the stabilizers.
Nice, finally big enough 3d printed plane. Didn't know it can be light enough to fly :) but i guess this takes quite long time to print, which is a bit of demotivation for me, haha.
I paused at the moment you showed OSD and was likw "WTF?! 70kph at 1 amp?" And then realized it's in a dive😅 Still, impressive consumption numbers, especially for such a heavy bird
Very well done. Wouldn't pouch batteries have a better energy-to-weight ratio than 21700 (steel cylinder housing)? Have you ever looked into whether winglets/sharklets have a positive effect on performance at model scale?
You definitely could find pouch cells with better performance, Tattu has some new Li-NMC batteries which beat most 21700 cells in terms of energy density. Amprius has their silicone anode stuff as well if you want to go all out. Unfortunately though those packs are way outside my (and most hobbyists) price range, and sourcing your own pouch cells to build a decent performing pack seems difficult. Basically, 21700 cells are cheaper and easier to source. I haven’t done any empirical testing or analysis on the effect of winglets, but my experience says they probably don’t make a noticeable difference. The reynolds numbers involved at this scale are just so much smaller than most general aviation and especially passenger jets.
@@gabejanssen4826 This is true! Considering your long spawn and generally high aspect ratio, winglets won't have any practical benefits. They're not really that useful in RC scales anyways, because like you said, the low Reynolds numbers.
How did you decide upon the dimensional requirements, (overall length, width). Is it just what would fit in your car? Did you design the longest wing that would fit? Or were you more worried about the segmentation from the printer volume, and kept it to a lower number of segments to increase structural integrity?
Merlin V1 was developed with the constraint of 2 meter wingspan and 1 meter length which was the biggest that could fit in my car. However that plane ended up not performing to my liking with my 6s6p samsung 50e pack I intended to run. So instead I developed Merlin V2 without the size restriction and focused on achieving better flight characteristics with that heavy pack, which led me to a higher aspect ratio, bigger wing area, thinner airfoil, and a bunch of other changes. Overall V2 has a roughly 17% increase in efficiency while also lowering the stall speed compared to V1.
It looks beautifully! Great job, Gabe. How long it takes to print all the parts (it depends of lot of factors, but anyway)? What printer do you have and how much material was used (approx)?
I would say around 90 print hours with my ender 3 S1, with a majority of the operations being between 5-10 hours. The design uses about 100g of TPU, 100g of PETG, and 1250g of LW-PLA.
I used XFLR5 and OpenVSP for the initial design, with verification in Fluent later in the development process. The maximum L/D of the whole airplane was predicted to be 19.41:1 at 2.1 degrees AOA
I didn't really track how many hours went into this, but its been a backburner project of mine for about 4 months. If I had to guess I would say I put in maybe 200 hours of work from project ideation to the point of this video
It would increase the strength, but the weight increase would hurt the performance. When a 3d printed plane crashes, it will almost definitely break no matter what filament it is made from, so IMO it is better to make it as light as possible rather than chasing durability with heavier materials.
amazing. What technique did you use for the inner structure. did you just print this in a low infill or did you model the inner ribs and wing structure uniquely
Both actually! The design primarily uses slicer infill for internal structure, with some extra ribs strategically placed inside the fuselage for extra reinforcement.
Gabe. How can i reach you? I have been working on a few things i think it would be interesting to collaborate! The twin engine setup is pretty slick and i like the amount of internal space.
The config shown flying in the video was just under 5kg all up weight, and it gets an efficiency of about 1.96Wh/ km. So roughly 92mah/km on a 6s Li-ion battery.
Optimal cruise speed at that weight is about 65kmh. Flying slower does decrease power draw which would increase endurance, however range goes by a function of speed divided by power draw. So it’s more about finding a balance between low power draw and high speed.
@@gabejanssen4826 I really appreciate you answering my questions. I might consider building it after I finish my first 3D printed plane from Eclipson. I just wish the durability of this LW-PLA was better.
@@IanF-FPV A couple of epoxy resin layers doesn't add too much weight and strengthens it a lot. I can't get pre-foamed locally and the active-foaming is like paper.
I have yet to do a full endurance test, but from my testing it should be able to achieve around 5.25 hours with a 6s6p samsung 50e pack. This design could also handle even bigger batteries.
I do not understand why now that we have 3D printing we are still building planes that look like this. I mean this body design was made that way because we transport people and we controlled the plane from a cockpit.
What would you suggest instead? There are a lot of reasons for this layout including weight distribution, diversity in battery/ payload options, ease of launch/ landing, aerodynamic stability, etc. Not trying to be argumentative, just saying there are more reasons beyond ‘this is what we’ve always done’.
CFD for a homemade RC plane is next level
Beautiful elegant lines 🧡
Bravo! I started flying R/C in the 70's and have been away from the hobby for 25 years and just now getting back into the hobby. I am shocked at the sheer number of poorly designed aircraft in the hobby market. We did not have this problem in the 70's through about mid 90's. Without knowing anything about you, you obviously are tied tightly with true aeronautical design principles. You need to put this design into production.........
Of course nowadays with cheap efficiënt power systems (lipo’s and brushless motor’s) there is no need for efficiënt airframes if you only need to fly 10 minutes or less.
60 bucks for an stl, had this guy heard of flightory?
@@CrystlizeWorldif you have a remote idea of how many hours go into designing, testing, proving, iterating again, validating, writing instructions, making videos, configuring the build.. etc, properly... Price is ok.
This is a beautiful plane.
I love the fuselage design! Altough I am not a fan of 3d printed uavs I really liked your design it looks so slick and I might even try 3d printing it on my ender3 v3 se when I have necessary components. Great work you are on my radar now have a nice day!
Thanks for the support!
Awesome build, what a monster! Love the wing bays, such a cool way to make use of the large wing size. The only gripe I have with the design is the fact that it has a non-continuous spar. From a structural point of view, this can be a little precarious. But considering you have an incredibly low wing loading anyways, it's likely not going to be an issue. I would expect you made this design choice because you couldn't source long enough carbon tubes to go the entire span?
Yep! Sourcing carbon fiber tubes longer than 1 meter is not easy, not to mention the shipping costs would likely be ridiculous. The combination of twist and taper in this wing would also make it difficult to do full length spars.
@@gabejanssen4826 Yeah, I usually limit my designs to what I can source without excessive costs like that. I presume you have some downward twist towards the wingtips to prevent tipstalling at high angles of attack?
Yeah, though only a little at about 3 degrees total twist. Elliptical lift distribution is achieved in this design by morphing the airfoil along the span, one of the many unique things 3D printing allows for in wing design.
@@gabejanssen4826 Some classic glider design solve this by inserting one step smaler diameter CF tude, which is also more weight and dimension optimal, since the profile at 1m from the wing root is usualy quite smaller.
0:33 all the batteries
1:45 oh that's neat the shake gesture to launch
1:50 anhedral?
Awesome design! I suppose it's around 5A in cruise, good result. Recently I designed similar twin motor plane, very stable scheme(have some videos on my channel. Which wing and tail profiles you have used?
I used a NACA 4409, 3408, and 2407 throughout the wing. It was very challenging to support such a thin airfoil but it payed off greatly in efficiency
It seems to me that a high efficiency plane should have an inverted V tail. It wouldn’t have the adverse roll in the turns to counteract so it would need less aileron deflection.
That's correct, inverted V-tails are generally superior in terms of flight dynamics. Unfortunately its hard to make a durable inverted V-tail without doing a twin boom design, which would likely introduce more drag. Also, during high efficiency flights you probably aren't doing tight maneuvers frequently enough for adverse roll to have a significant effect on efficiency. Although I could see the affect being more noticeable in gusting winds.
@@gabejanssen4826 It'd still be more drag in absolute terms but you could probably minimize the amount of drag from an inverted V-tail by taking advantage of the ability to print complex curving structural elements. Either by having a smooth fork of the main tail to support the stabilizers, or by curving a single tail upwards like a whales tail to hold the bottoms of the stabilizers above the ground during landings. could even get weird with it and make a three pronged forked fuselage that supports all three points of the stabilizers.
Awesome work! Thanks for sharing
Nice, finally big enough 3d printed plane. Didn't know it can be light enough to fly :) but i guess this takes quite long time to print, which is a bit of demotivation for me, haha.
Long print times are the best! Even lying on my ass watching TV, I can tell myself the printer's running so I'm still making progress on the build 😆
Fantastic plane I'm currently printing it in pteg, could do with t and g joints on wings
Wow... have you made some experience with the ASA Aero Filament from Bambu ? could be worth a try
I paused at the moment you showed OSD and was likw "WTF?! 70kph at 1 amp?" And then realized it's in a dive😅
Still, impressive consumption numbers, especially for such a heavy bird
I would buy on cults if EDF version.
I am also looking for decent BWB and tandem box wing.
That looks awesome, damn!
Very well done. Wouldn't pouch batteries have a better energy-to-weight ratio than 21700 (steel cylinder housing)? Have you ever looked into whether winglets/sharklets have a positive effect on performance at model scale?
You definitely could find pouch cells with better performance, Tattu has some new Li-NMC batteries which beat most 21700 cells in terms of energy density. Amprius has their silicone anode stuff as well if you want to go all out. Unfortunately though those packs are way outside my (and most hobbyists) price range, and sourcing your own pouch cells to build a decent performing pack seems difficult. Basically, 21700 cells are cheaper and easier to source.
I haven’t done any empirical testing or analysis on the effect of winglets, but my experience says they probably don’t make a noticeable difference. The reynolds numbers involved at this scale are just so much smaller than most general aviation and especially passenger jets.
@@gabejanssen4826 This is true! Considering your long spawn and generally high aspect ratio, winglets won't have any practical benefits. They're not really that useful in RC scales anyways, because like you said, the low Reynolds numbers.
Twin motors were armed at launch speed by shaking the plane along the roll axis ... clever indeed
Wow, this thinf has some speed
How did you decide upon the dimensional requirements, (overall length, width). Is it just what would fit in your car? Did you design the longest wing that would fit? Or were you more worried about the segmentation from the printer volume, and kept it to a lower number of segments to increase structural integrity?
Merlin V1 was developed with the constraint of 2 meter wingspan and 1 meter length which was the biggest that could fit in my car. However that plane ended up not performing to my liking with my 6s6p samsung 50e pack I intended to run. So instead I developed Merlin V2 without the size restriction and focused on achieving better flight characteristics with that heavy pack, which led me to a higher aspect ratio, bigger wing area, thinner airfoil, and a bunch of other changes. Overall V2 has a roughly 17% increase in efficiency while also lowering the stall speed compared to V1.
such a cool project so many questions, would love to see more flight footage!! In what 3d program did you design that beauty?
Type of camera ?
Красивый самолет
Can I ask which airfoil you are using? Is it NACA 2412 or another one?
According to another comment of OP's, it is a mix of NACA 4409, 3408, and 2407 throughout the wing
It looks beautifully! Great job, Gabe.
How long it takes to print all the parts (it depends of lot of factors, but anyway)? What printer do you have and how much material was used (approx)?
I would say around 90 print hours with my ender 3 S1, with a majority of the operations being between 5-10 hours. The design uses about 100g of TPU, 100g of PETG, and 1250g of LW-PLA.
What CFD program did you use? What was the lift to drag?
I used XFLR5 and OpenVSP for the initial design, with verification in Fluent later in the development process. The maximum L/D of the whole airplane was predicted to be 19.41:1 at 2.1 degrees AOA
This is so impressive
how long did it take you to design the whole aircraft ??
I didn't really track how many hours went into this, but its been a backburner project of mine for about 4 months. If I had to guess I would say I put in maybe 200 hours of work from project ideation to the point of this video
what a cool plane, a full PLA version would not be stronger overall even if it increases a bit the weight?
It would increase the strength, but the weight increase would hurt the performance.
When a 3d printed plane crashes, it will almost definitely break no matter what filament it is made from, so IMO it is better to make it as light as possible rather than chasing durability with heavier materials.
@@gabejanssen4826 you use IMO or LWPLA?
@ thanks for your kind reply
Which airfoils did you use?
which CFD you used
the answer is down below
amazing. What technique did you use for the inner structure. did you just print this in a low infill or did you model the inner ribs and wing structure uniquely
Both actually! The design primarily uses slicer infill for internal structure, with some extra ribs strategically placed inside the fuselage for extra reinforcement.
Looks great, what is Cd?
Roughly 0.024 @ -2 degrees AOA.
Gabe. How can i reach you? I have been working on a few things i think it would be interesting to collaborate! The twin engine setup is pretty slick and i like the amount of internal space.
Wow love the wingspan size and battery capacity. You using the lw-pla or lw-asa?
Thanks! This was made from prefoamed LW-PLA with select parts in PETG or TPU
What Filament is it? An "Aero" filament?
This is mostly pre-foamed LW-PLA, with some parts in TPU or PETG
4amps at over 60 kph is amazing. What is the mah consumption per km?
The config shown flying in the video was just under 5kg all up weight, and it gets an efficiency of about 1.96Wh/ km. So roughly 92mah/km on a 6s Li-ion battery.
@ not too bad..is that at 60kph? If so can you fly slower for better numbers?
Optimal cruise speed at that weight is about 65kmh. Flying slower does decrease power draw which would increase endurance, however range goes by a function of speed divided by power draw. So it’s more about finding a balance between low power draw and high speed.
@@gabejanssen4826 I really appreciate you answering my questions. I might consider building it after I finish my first 3D printed plane from Eclipson. I just wish the durability of this LW-PLA was better.
@@IanF-FPV A couple of epoxy resin layers doesn't add too much weight and strengthens it a lot. I can't get pre-foamed locally and the active-foaming is like paper.
What was your final endurance time with its all up weight?
I have yet to do a full endurance test, but from my testing it should be able to achieve around 5.25 hours with a 6s6p samsung 50e pack. This design could also handle even bigger batteries.
That was at an all up weight of about 4.8kg, max weight I would recommend is 6.5kg.
STLs available? @gabejanssen4826
Yep! Check the description
how did you do that
Dude that is sweet
NICE!
amazing!
Too bad model is not optimized for active foam lw-pla... would have buy it; this way it's just "yet another" 3d printed uav.
I can't get pre-foamed locally so epoxy resin has become my friend.
Bravo!
awesome)
Süper dilo
Really nice design
I do not understand why now that we have 3D printing we are still building planes that look like this. I mean this body design was made that way because we transport people and we controlled the plane from a cockpit.
What would you suggest instead? There are a lot of reasons for this layout including weight distribution, diversity in battery/ payload options, ease of launch/ landing, aerodynamic stability, etc. Not trying to be argumentative, just saying there are more reasons beyond ‘this is what we’ve always done’.
Pls send me files for free thank you
sorry. it's W O N K Y !!!