Place the fuselage in a rotisserie, which will allow you to rotate the fuselage 360 degrees. Then you wouldn't be cramping your body when trying to paint various areas of the fuselage. A rotisserie is also used to hold a welded tube fuselage to be able to apply the fabric covering. Keep up the good work ! 🙂
@@lamberto6405 Not really. The height of the rotisserie is very adjustable, on pre-made units. This would need to be a custom built rotisserie to accomplish a full rotation - but - it can be done.
We considered something like this initially, but decided that for the minimal amount of time we’ll be spending to paint the fuselage it was a decent trade off to just do some painting in awkward positions compared with implementing a rotating jig. A nice side effect of having a light fuselage is that two of us can easily rotate it when we have to.
I'm not a professional painter. I am a fabricator. But I need to paint everything. And when I say everything, it includes a lot of sizes and shapes. I built myself a universal Rotisserie that holds pretty much anything. Including a lead clocktower from the top of a college. If you have more projects coming, it might be a good idea. The one I built breaks down and stores easily. Also transportable and easily moved around and set up by one person.
I have been building composites and the molds for them for over ten years, I worked building mid-size drones for six years. If you haven't already, you may want to consider; First, waxing/seasoning your mold surface I can't remember if we could use the TR 104 for painted surfaces, or the Partial Paste #2 (we waxed/seasoned new molds five times, less is needed after you start pulling parts, and you will want to play around with different types of wax, my preferred was TR 104, but I did both painted and unpainted parts, as well as different mold and mandrel materials and cloths carbon, kevlar, and glass). After you pull a part from the mold, wash both the mold and the part with dawn soap and warm water. Second, DO NOT USE the PVA. The painter and I spent a couple of days playing with different combinations of wax as well as PVA/no PVA. You do not gain anything from it beyond potential runs on the mold surface, which result in low spots in the paint which need filling, and consequently adding an uneven distribution of mass via filler to the surface as well as changing it's shape. Yes, these small variations can be taken care of with trim, but that is additional drag. Third, just paint the waxed/waxed and PVA'd mold surface. You will want to play around with WHEN you start your layup on the painted mold surface to get a feel for your paint/resin finish and bond. When you paint the mold surface, you end up with no pinholes. When you paint the wings/fuselage/cowls/spinner cones et cetera, you DO end up with pinholes. Fourth, when you paint the mold surfaces, you skip then entire priming process, and that saves a significant amount of mass. Fifth, you may consider a temperature stepping post-cure, to toughen your parts. You will need a large oven with a good blower to circulate that air for your wings and fuselage, but easy enough to make with cinderblocks. I am sure you are aware that it is pretty easy to damage sharp/thin areas, and carbon is soft. That post cure helps a lot, and makes working/repairing go a little better. Talk with your resin supplier about this. Sixth, you may want to think VERY HARD about a surface layer of 1oz glass or to provide a tougher surface than carbon. It also eliminates the issue of the cloth pattern printing through the paint.
Why not use gelcoat when you mold the wing skins, as they do on boats? If the gelcoat is heavier than paint, WHY is it heavier? Is there some reason the gelcoat has to be thicker than paint and primer would be?
He would have to at least prime it first to seal the carbon fiber or use a clear epoxy! But it is a good idea if the wrap will hold up to high speeds constantly!
I remember as child (years 1970's) I was "allowed" to polish with waterproof sandpaper repair spots on gliders. They were painted with a coat of what they called "Schwabbellack" and polished afterwards . A lot of work but with perfect smooth result. The new ones produced by for example Schleicher, Glasflugel and others were 'prepainted' in the molds. the molds were first sprayed with this Schwabbellack befor the glass or carbon fibers were placed. Nice to see the plane painted white for the reasons you mentioned (and to prevent the sun warming up the epoxy) and not showing the carbon despite how nice carbon may look.
The early composite gliders used gelcoat as their surface finish and this was applied in the molds. Gelcoat is a polyester resin with pigment. Repairs on gelcoat use flowcoat which is the same as gelcoat but with added wax solution so the surface can cure properly and can be refinished. Unfortunately polyester gelcoats do not weather well and will craze, blister or crack over time. It is desirable in the secondhand glider market to purchase an older glider that has been refinished with a polyurethane paint, as this is much longer lasting and easier to repair.
for your paint problems, the 3m pps solution is one of the most suitable. the flexible vacuum pocket system allows the spray gun to be painted in any position. I personally painted a p300 pioneer, concerning the lower part of the fuselage the most practical remains" the mechanic's horizontal wheeled trolley". nice project, do you have any particular feedback on the inflatable paint booth?
The 3M PPS system is similar to what we used in the video, which was the DeKups system by Devilbiss. We like it a lot! The inflatable booth works well for our requirements where we’ll just be painting our plane and storing the tent for production. We’d recommend it for anyone that just needs a semi-temporary clean space for painting. The link to the tent we used can be found above in the description of the video.
@@DarkAeroInc Did you hold the gun upside down at the start and pull the trigger? that sucks all the air out of the paint cup and you should be able to spray on any angle including upside down.
I'm from the Auto Body Painting world. Some advice would be to build a jig that has a base on the ground with wheels and then connects to the fuselage to it on the engine mount points and the tail section (viticle stabilizer area) The mounts must be on a bearing system at both ends to allow you to roll it when painting.
I thought about this too and that's what we use into manufacturing bigger vehicles, but their market is a guy like us doing that in their garage, so building a whole rotisserie fixture might be too much. I think putting the aircraft up 1-2 feet more would help in painting the bottom part and then using a ladder for the top.
Yes but they wear down over time, and rather quickly. You see it often on cars that have exposed carbon on them. The clear coat starts to flake and yellow.
I am a 45 year ( Just retired ) PPG Automotive Paint Refinish Technician and you will have better results if you go with 2 quart pressure Pot paint spray system, many manufacturers still make them , Anest Iwatta, DeVilbiss, Binks. Its a very easy to use spray gun , as all you have is the gun and a couple hoses in your hand , and with a pressure filled system the paint sprays in any position with no spitting or sputtering. But the real bitch of this system is making sure you take off the FLUID HOSE and CLEAN IT VERY VERY well, this is the BANE of a pressure pot system, but works so well on big spray projects, I used mine when I had to spray complete Box Vans and Suburbans and the like . Try this and I think you will like the ease of spraying. Cool ass airplane too by the way 👍😎
I know that in boats, they sometimes paint the mold before adding the laminates. Not sure if that process could work for you. It might slow down production too much.
This is Gelcoat technology and its great for boats and it would also work for aircraft. But, gelcoat has long term issues as it degrades over time and is difficult to repair. Laying up quality composite materials in smooth molds under vacuum should produce a smooth and pinhole free surface thats as easy to paint as a scale plastic model. I believe there is a wide discrepancy in builder hours to fill, sand and paint Rutan style mold-less composite aircraft. First, RAF prototypes were often built and flown with fewer man-hours start to finish than some people claim to have spent just on sanding filler on their projects. There is a wide variance in not only skillset and productive ability, but also in mental concepts about what the task actually entails. And what level of finish can be archived with a certain process. People don't know whats involved, and the EAA is full of "expert" builders offering advice like how to sand and finish composites who also believe it takes 2,000hrs to do it right. But their claim to fame is taking 20 years to build a grand champion that deviated from the instructions in two hundred places and required re-building and fixing and fitting. And then there are absolute masters of finishing who can make a true laminar surface award winning Velocity or LongEZ and they claim they have leas than two weeks of sanding on the whole airplane to get there. True experts who are highly Productive generally dont waste their time trying to teach people of mediocre ability who lack potential. They work fast alone. And cant convey the nuance of what they do verbally. And teaching hands on takes ten times as long to demonstrate.
@@Triple_J.1 the vast majority of boats use gelcoat. But sometimes for epoxy/fiberglass boats, they spray the mold with 2 component polyurethane paint before putting down the laminates. Gelcoat would be terrible for dark aero. But taking the time to have a perfect mold, and then spraying it with paint prior to placing the laminate, that could be a huge long-term time saver.
@@appa609 40kg would be a pretty heavy paint-job on a plane this small. Hopefully its closer to 30-40 pounds. (I just finished painting my kit airplane, also a small 2-seater, and the paint job was around 30-35 pounds; though I used a different primer & paint system so its not exactly apples-to-apples)
We will definitely get a weight total on the airframe after painting to check how much was added and assess our process. The total amount of primer that was mixed and prepared to paint both the wing and fuselage was ~8.5lbs. This gives us an upper limit on how much paint is currently on the airframe since we sanded a lot of this off on the wing and not all of it was applied to the airframe either because of overspray or leftovers in the cup. The true amount on the airframe is probably closer to 5-6 lbs presently, but we will come back to this topic once we have completed the priming and have done a final weight check.
Prime, no problem splitting operations. However, when painting you will need to get it all in one go or you will have some dry spot issues and will need to prep the airplane a certain way for round 2. I’m sure you know this already just wanted to make sure! Thing looks sick all white!!!
0:50 same thing with F1 cars,they are mostly carbon fiber chassis and the paint protects and removes some of the drag of the car (also sponsors of course), some teams like mclaren have removed paint from parts of the cars like bottom of surfaces and etc.
Too late now but there’s a product called xcr coating which has uv protection and a shiny clear surface it also self levels it’s used a lot in carbon manufacturing I run my own carbon company so thats how I know. If you ever make spare parts or new/updated parts maybe consider it as it would look awesome in visual carbon.
may want to look at a suspension cradle/crane for paint ... will allow painters complete under access and the ability to lower/raise the surface being worked on ... cradle may be set to rotate +-45
It's great to see you are making progress! I come from gliding, so painting composite aircraft makes total sense. We use a PU or in older gliders UP gelcoat, and we use special templates for sanding to make sure that the profiles are shaped right after painting!
I love seeing this thing progress, excellent work, have you guys ever tried slicksand? Basically a polyester high build primer, it's been one of the best things I've found to get my composite stuff optically flat for paint, you can build it up so easily and quickly that I never even bother with filler nowadays, not on composite stuff anyway which is already so close to right.
@@kwittnebel Yes. We spray it in our tools and let it cure/dry then infuse the parts inside the coating. It's recommended to scuff the part and primer before paint. Many customers use epoxy primer .
I noticed while getting back in to doing some body work that there's new primer fillers on the market that seem to be the new "thing". Basically it's a lightweight primer with more filling. Not sure if there's such a product that's good for aviation, but it looks like you're not using that zinc phosphate primer, so maybe automotive primer is OK? If so, I could see it being very useful in QC during production for the first coat.
I remember listening to a radio interview with a late war spitfire pilot - flying a griffon engine with clipped wings. He was obsessive about aerodynamic cleanness. He filed down the rivets on his plane and filled in all of the rivets an smoothed over joints. After every flight he would clean and polish his plane etc. The result was that his plane was something like 40 mph faster than other Spitfires. (I'm stretching my recollection here, I reckon this interview was in the 90s) He shot down a few Me-262s. They just didn't appreciate that he was almost as fast as them. Anyway, moral of the story... I can totally see where you are coming from. Obsessing about aerodynamic cleanness can have huge payoffs.
What about galvanic issues with the conductivity of carbon fibre ? We saw recently the feud between Emirates and Airbus because of the paint cracking, owing to the electrostatic characteristics of the carbon fibres.
The rotisserie idea is the best, just some other thoughts on how to paint. Look for an old Model 7 Binks (1-quart-size) suction spray gun, or to make your life much easier, go with a pressure "Spray-Pot," setup. FYI Spray-pots come in all different sizes, from 1 quart size, up to 20 gallon spray-pots, with air operated constant mixing / stirrer (BIG $$$$.) Another option is to go "Airless - Spray setup," that's what we used when painting 747 Wings, and be able to keep the entire wing paint wet during cross lap's. As someone who has 25 yr's autobody experience, 5 year's as a painter 747's & 767's Boeing Aircraft, Everett, Washington, U.S.A., the word Epoxy and flexible is a non starter. Flexible = Polyurethane, Epoxy = rigid / kitchen stove top finish, read it and weep.
Would it be possible to set the fuselage on a jig that allowed it to rotate (bank) 90' to make it easier to do the top and bottom? Looking great and thanks for the update!
OOooo, vacuum infusion. I did some composite fab work a couple years ago on some fancy new Q/V band satellite antennae, and we used vacuum infusion for all our parts. I wasn't involved in quality control for the actual reflector surface, but I believe our tolerances were something like 50 microns, and as far as I know rework was basically never needed outside of issues caused by leaky bags, wrinkled layups, and thermal runaway. Now that i've done it that way, I don't think I'd ever use wet lay ups for anything but repairs and the quick-and-dirtiest of projects.
There are both matte and gloss UV clear coats you could use. They can be sanded/faired and resprayed at the range of surface variation you are describing. I would use a filler made black with carbon dust and tape the joints off for even appearance.
And of course, the gel coat colour chosen, "white", helps to reflect the sunlight which would also contribute to keep the temperature lower inside the airplane, while on ground! The resin used on the skins, could also "suffer", just in case the gel coat was pigmented black, for instance... It could "melt" a little bit!
I think you need a chassis rotisserie. They are made for cars (to access everything during restorations) but one could be adapted to a plane fuselage (without wings).
My friend made a straw bale house, a building where walls are straw bales coated with a plaster concrete. For marketing to show the interior of walls were actually made of compressed straw he put a small window in the plaster of one wall in a high traffic area. Can you leave a small area unpainted or coated with clear UV coating to show your plane is made of CF? I know this is just window dressing so to speak but it could change perception of the vehicle even slightly.
Hi guys thanks for your effort in revealing so much of your build. Thought...to paint fuselage a 'skewer' rig and rotate as you paint. Not a lot more work considering what you have already done.
For painting any tubular section of the fuselage you really need to have 2x pyramidal triangular frames with pillow block bearings at the top so that you can attach an axle at either end of the fuselage & you'll be able to spin the plane 3t60 degrees for painting optimally in the best light as well. You could attach a temporary jig that attaches to the vertical stabilizer that has a horizontal pipe that fits into a pillow block bearing at one end & put an engine mounted jig that also mounts to a horizontal pipe that goes into the pillow block bearing.
@@acruzp and here comes the fix for the content: Precicely because the Reynolds numbers of model airplanes are so small, combined with the fact that there are laminar flow airfoils for them, means that full scale planes must be able to have large sections of laminar flow, whose Reynolds numbers are gigantic, compared to those of model airplanes.
@@acruzp : that is very true - laminar flow is maintainable during the "positive pressure gradient" sections of a wing - it breaks down on the back end of the pressure gradients. (Often the "laminar aspects" of aerodynamics are moderately overstated. Many laminar flow wings tend to have very narrow AOA windows and rather unsafe behaviour - they rarely stall progressively)
I noticed that you didn't mention *heat buildup* from *sunlight* as a problem for carbon fiber parts. Back in the days of glass-fiber-on-polyurethan-foam, that was a reason to paint parts white. Is heat not a problem for a carbon fiber composite?
One additional reason for painting the aircraft; solar heating of composite materials can weaken them. Gliders are usually white. to avoid warming them to floppiness What is the weight of the paint and fillers likely to be?
For production I think a rotating jig that works like a rotisserie would work really well. Should just require two metal rod to serve as axles with a flange welded to one end that allows one axle to be bolted into the bolt holes for the rudder in the back and the other to the engine mount in the front with the axles in line with each other. A-frame stands for the front and rear with two bearing each at the apex of the "A" supports the axles. Oh, and by using two bearings on each stand, there are no bending forces in the flange and into the fuselage like there would be if a single bearing was used. To make it easier to get the axles go through the bearings as the A-frames are moved over the axle, you could make the axle OD smaller than the bearing ID. Then thread the axle and put one threaded collar with a tapered OD on the axle first with the taper facing towards the bearings. Slide the A-frame and the bearings over the axle to the desired position along the axle. Then thread a second tapered collar onto the axle and screw both collars so the tapered end goes into a bearing until both are snug to take out the play between the axle and the bearings. This also serves to lock the A-frame to the axle. Once both A-frames are in position, two "ladders" trusses made with square tubing and cross pieces at 45 degree angles could be used to lock base of the two A-frames together. I suggest this ladder structure so that an racking forces as the fuselage is rolled into the painting bay go through the ladders rather than the axles and the fuselage. Once in the paint bay, thread a crank handle onto the end of each axle and you can easily use it to rotate the fuselage to allow you to paint every section from the optimum angle. No more having to stand on a box and stretch to spray the top or squat and try to spray upward to get the bottom, while still allowing the entire fuselage to be painted at one time. Sorry if this is over the top, but I am a design engineer and I can't help but see design solution leap unbidden into my mind's eye.😊
My first thought was the need to lower drag but covering that uv sensitive epoxy definitely requires a coat. Don't want your plane falling apart in the hanger or even the air.
You guys have made such a fantastically light fuselage, it may not take much to create a jig that rotates the body along the longitudinal axis while in the paint booth. It may pay itself off in reduced spraying/sanding time.
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You succeeded in removing a great deal of the Suck in painting composites in your crafting the high-precision molds. A front line finish is still going to swallow many hours, but Dark Aero’s construction methodology will save many more hours. It’s a big Win, overall.
Are there any paint guns available that can spray upwards? Even if the nozzle was tilted up at 45* that might be enough to reach the underside of the wing better and that corner under the horizontal stab would be a piece of cake.
The gun and cup system we used can spray while tilted upward. This is how we were able to paint the inverted surfaces. My complaint about the setup was that it isn’t ideal to crouch under the airplane to paint the underside.
Awesome project. How did your Sherwin Williams fill bond filler at the stabilizers work out after painting. Ever see any cracks yet? In marine use, we tend to apply g-flex from west system. I guess the stuff you used is much lighter.
In the past I've heard one of the main reasons airplanes have been tradionally painted white is so that stress cracks can be more easily seen. Are cracks not an issue with carbon fibre?
B17s were painted [70ishlbs extra weight] they did a paint, unpaint test to evaluate the weight saving and found that fuel consumption went up by 3% on unpainted airframes, the extra fuel to recoup the 100mile range loss was heavier than the paint.
2 роки тому+4
It's going to take some getting used to the new look. Maybe Light Aero or White Aero now instead of Dark Aero? Anyway, I love following this project. Happy Thanksgiving!
We will top coat it eventually, but we will probably fly it in primer first. Still deciding on the final color scheme. Thanks for checking out the video!
I work with cf on a hobbiest level and you can just use a UV stable clear coat but I'm sure there are also other reason you'd like to not make an airplane essentially all black
This video got me curious about a couple of things. I looked them up on line and it is evidently possible to powder coat carbon fiber which makes sense because carbon fiber is electrically conductive. Was powder coating a consideration among the painting options? The second thing was lightning protection which led me to a website that said composite materials are poor conductors of electricity and they build airplane parts with an integrated conductive mesh to address this issue. What kind of lightning protection does your plane have?
all about getting it done... if you can somehow get an acceptable product spraying just once, do it. it saves a lot of time and money, but takes more care and prep on the surface parallel to the ground.
i have heard of companies spraying their molds with primer, prior to layup. then there is so much less paint prep work, because the primer takes to the mold, then the composite to that. i would be the first to paint a carbon fiber airplane, for the reasons mentioned, and the reflectivity to minimize the solar heat.
1:34 is it that carbon fiber doesn’t require the sanding that foam/fiberglass does, or is it just the molds that removes the need whatever the material?
Nice job guys! I'm sure you know already, and just didn't mention it. One of the main reasons plastic airplanes are painted white or a light color is because of heat. The difference between black and white in the sun is huge. Heat (oil and UV light) is an enemy of anything composite. ...composites don't work harden like aluminum, they just snap. Incidentally, you should put a coat of paint on the inside of the engine cowling for oil protection. It's not structural but it will prevent delamination and make it easier for repairs later. Cheers!
Would it put too much stress on the engine mounts if you used them to mount the fuselage on a rig that would allow it to rotate on it's longitudinal axis kinda like being on a rotisserie?
Ten years ago, painting was completed on the first Boeing 787 in Everett, WA and it came out looking really slick. Little did Boeing or Airbus know at the time that the paint would at some point peel off from composite surfaces. Emirates got really mad at Airbus for their peeling paint and Boeing has also had its issues with peeling paint. 🤠
In the aerospace world (using pre-preg carbon fiber), the first ply against the mold surface is always a very thin sheet of resin rich pre-preg to give you a good surface without needing any filler. The aircraft in this video, even though you didn't use any filler, required a lot of extra coats of primer to get a good finish. This probably added 20-25 pounds to the weight of the aircraft.
It is amazing how hot a carbon skin gets in the sun. I had a carbon surfski (racing kayak) with a clear coated hull. Looked cool but got crazy hot in the sun.
Yes, this aircraft will be sold in the experimental category as a kit. We have started taking deposits for the kit. More information can be found on our website: darkaero.com/aircraft.
My inner child says if you add racing stripes and flame decals, it will absolutely go at least 1% faster
You are giving away all our engineering secrets! XD
Red definitely helps
Experiments prove more like 2-3%
Add Skulls & Crossbones to get at least 3% 🏴☠️
I understand a shark mouth usually gets you 1-2% higher speeds
Place the fuselage in a rotisserie, which will allow you to rotate the fuselage 360 degrees. Then you wouldn't be cramping your body when trying to paint various areas of the fuselage. A rotisserie is also used to hold a welded tube fuselage to be able to apply the fabric covering. Keep up the good work ! 🙂
Kinda tough with that long horizontal stabilizer in place.
@@lamberto6405 Not really. The height of the rotisserie is very adjustable, on pre-made units. This would need to be a custom built rotisserie to accomplish a full rotation - but - it can be done.
We considered something like this initially, but decided that for the minimal amount of time we’ll be spending to paint the fuselage it was a decent trade off to just do some painting in awkward positions compared with implementing a rotating jig. A nice side effect of having a light fuselage is that two of us can easily rotate it when we have to.
Or you can just use a pot gun instead of a gravity fed one.
I'm not a professional painter. I am a fabricator. But I need to paint everything. And when I say everything, it includes a lot of sizes and shapes. I built myself a universal Rotisserie that holds pretty much anything. Including a lead clocktower from the top of a college. If you have more projects coming, it might be a good idea. The one I built breaks down and stores easily. Also transportable and easily moved around and set up by one person.
Great to see you are this far with the DarkAero. I think it is probably the best thought out light plane in history.
It is a beautiful plane. It looks fast.
I have been building composites and the molds for them for over ten years, I worked building mid-size drones for six years. If you haven't already, you may want to consider;
First, waxing/seasoning your mold surface I can't remember if we could use the TR 104 for painted surfaces, or the Partial Paste #2 (we waxed/seasoned new molds five times, less is needed after you start pulling parts, and you will want to play around with different types of wax, my preferred was TR 104, but I did both painted and unpainted parts, as well as different mold and mandrel materials and cloths carbon, kevlar, and glass). After you pull a part from the mold, wash both the mold and the part with dawn soap and warm water.
Second, DO NOT USE the PVA. The painter and I spent a couple of days playing with different combinations of wax as well as PVA/no PVA. You do not gain anything from it beyond potential runs on the mold surface, which result in low spots in the paint which need filling, and consequently adding an uneven distribution of mass via filler to the surface as well as changing it's shape. Yes, these small variations can be taken care of with trim, but that is additional drag.
Third, just paint the waxed/waxed and PVA'd mold surface. You will want to play around with WHEN you start your layup on the painted mold surface to get a feel for your paint/resin finish and bond. When you paint the mold surface, you end up with no pinholes. When you paint the wings/fuselage/cowls/spinner cones et cetera, you DO end up with pinholes.
Fourth, when you paint the mold surfaces, you skip then entire priming process, and that saves a significant amount of mass.
Fifth, you may consider a temperature stepping post-cure, to toughen your parts. You will need a large oven with a good blower to circulate that air for your wings and fuselage, but easy enough to make with cinderblocks. I am sure you are aware that it is pretty easy to damage sharp/thin areas, and carbon is soft. That post cure helps a lot, and makes working/repairing go a little better. Talk with your resin supplier about this.
Sixth, you may want to think VERY HARD about a surface layer of 1oz glass or to provide a tougher surface than carbon. It also eliminates the issue of the cloth pattern printing through the paint.
Why not use gelcoat when you mold the wing skins, as they do on boats? If the gelcoat is heavier than paint, WHY is it heavier? Is there some reason the gelcoat has to be thicker than paint and primer would be?
Did you consider wrapping it? It has been done for fixed wing UAVs to give a smoother surface than paint at a lower weight.
He would have to at least prime it first to seal the carbon fiber or use a clear epoxy! But it is a good idea if the wrap will hold up to high speeds constantly!
I dont think it would have to be sealed if the finish is allready 800grit smooth ...
Paints are aerospace-proven. Wraps are not, sadly.
I remember as child (years 1970's) I was "allowed" to polish with waterproof sandpaper repair spots on gliders. They were painted with a coat of what they called "Schwabbellack" and polished afterwards . A lot of work but with perfect smooth result. The new ones produced by for example Schleicher, Glasflugel and others were 'prepainted' in the molds. the molds were first sprayed with this Schwabbellack befor the glass or carbon fibers were placed.
Nice to see the plane painted white for the reasons you mentioned (and to prevent the sun warming up the epoxy) and not showing the carbon despite how nice carbon may look.
The early composite gliders used gelcoat as their surface finish and this was applied in the molds. Gelcoat is a polyester resin with pigment. Repairs on gelcoat use flowcoat which is the same as gelcoat but with added wax solution so the surface can cure properly and can be refinished.
Unfortunately polyester gelcoats do not weather well and will craze, blister or crack over time. It is desirable in the secondhand glider market to purchase an older glider that has been refinished with a polyurethane paint, as this is much longer lasting and easier to repair.
for your paint problems, the 3m pps solution is one of the most suitable.
the flexible vacuum pocket system allows the spray gun to be painted in any position. I personally painted a p300 pioneer, concerning the lower part of the fuselage the most practical remains" the mechanic's horizontal wheeled trolley".
nice project,
do you have any particular feedback on the inflatable paint booth?
The 3M PPS system is similar to what we used in the video, which was the DeKups system by Devilbiss. We like it a lot! The inflatable booth works well for our requirements where we’ll just be painting our plane and storing the tent for production. We’d recommend it for anyone that just needs a semi-temporary clean space for painting. The link to the tent we used can be found above in the description of the video.
@@DarkAeroInc Did you hold the gun upside down at the start and pull the trigger? that sucks all the air out of the paint cup and you should be able to spray on any angle including upside down.
I'm from the Auto Body Painting world. Some advice would be to build a jig that has a base on the ground with wheels and then connects to the fuselage to it on the engine mount points and the tail section (viticle stabilizer area) The mounts must be on a bearing system at both ends to allow you to roll it when painting.
I thought about this too and that's what we use into manufacturing bigger vehicles, but their market is a guy like us doing that in their garage, so building a whole rotisserie fixture might be too much. I think putting the aircraft up 1-2 feet more would help in painting the bottom part and then using a ladder for the top.
@@TheBarzook There are home auto enthusiasts that use rotisseries. It seems extreme at first, but it's not unreasonable.
The monologue at the beginning answered all the questions that I had after immediately considering the problem - well done
Hey, any chance you could post a high resolution version of the picture in 0:37? I'd love to make it my new wallpaper :)
Even after the first coat of paint the aircraft looks CG as the lines and contours are so perfect! Nice work!
It’s probably already been asked, but isn’t their a UV blocking clear coat that you could use? I think I’m just too in love with the carbon fiber look
Yes but they wear down over time, and rather quickly. You see it often on cars that have exposed carbon on them. The clear coat starts to flake and yellow.
have sunlight directly hit on carbon fibre is just slow burning money
I am a 45 year ( Just retired ) PPG Automotive Paint Refinish Technician and you will have better results if you go with 2 quart pressure Pot paint spray system, many manufacturers still make them , Anest Iwatta, DeVilbiss, Binks.
Its a very easy to use spray gun , as all you have is the gun and a couple hoses in your hand , and with a pressure filled system the paint sprays in any position with no spitting or sputtering.
But the real bitch of this system is making sure you take off the FLUID HOSE and CLEAN IT VERY VERY well, this is the BANE of a pressure pot system, but works so well on big spray projects, I used mine when I had to spray complete Box Vans and Suburbans and the like .
Try this and I think you will like the ease of spraying. Cool ass airplane too by the way 👍😎
I know that in boats, they sometimes paint the mold before adding the laminates. Not sure if that process could work for you. It might slow down production too much.
This is Gelcoat technology and its great for boats and it would also work for aircraft. But, gelcoat has long term issues as it degrades over time and is difficult to repair.
Laying up quality composite materials in smooth molds under vacuum should produce a smooth and pinhole free surface thats as easy to paint as a scale plastic model.
I believe there is a wide discrepancy in builder hours to fill, sand and paint Rutan style mold-less composite aircraft. First, RAF prototypes were often built and flown with fewer man-hours start to finish than some people claim to have spent just on sanding filler on their projects. There is a wide variance in not only skillset and productive ability, but also in mental concepts about what the task actually entails. And what level of finish can be archived with a certain process. People don't know whats involved, and the EAA is full of "expert" builders offering advice like how to sand and finish composites who also believe it takes 2,000hrs to do it right. But their claim to fame is taking 20 years to build a grand champion that deviated from the instructions in two hundred places and required re-building and fixing and fitting. And then there are absolute masters of finishing who can make a true laminar surface award winning Velocity or LongEZ and they claim they have leas than two weeks of sanding on the whole airplane to get there. True experts who are highly
Productive generally dont waste their time trying to teach people of mediocre ability who lack potential. They work fast alone. And cant convey the nuance of what they do verbally. And teaching hands on takes ten times as long to demonstrate.
@@Triple_J.1 the vast majority of boats use gelcoat. But sometimes for epoxy/fiberglass boats, they spray the mold with 2 component polyurethane paint before putting down the laminates. Gelcoat would be terrible for dark aero. But taking the time to have a perfect mold, and then spraying it with paint prior to placing the laminate, that could be a huge long-term time saver.
Will you weigh the parts before and after the paint is applied to determine how much weight is being added by the painting process?
Based on the process I'd guess about 1000 gsm. Maybe 40 kg for the whole aircraft?
@@appa609 40kg would be a pretty heavy paint-job on a plane this small. Hopefully its closer to 30-40 pounds.
(I just finished painting my kit airplane, also a small 2-seater, and the paint job was around 30-35 pounds; though I used a different primer & paint system so its not exactly apples-to-apples)
We will definitely get a weight total on the airframe after painting to check how much was added and assess our process. The total amount of primer that was mixed and prepared to paint both the wing and fuselage was ~8.5lbs. This gives us an upper limit on how much paint is currently on the airframe since we sanded a lot of this off on the wing and not all of it was applied to the airframe either because of overspray or leftovers in the cup. The true amount on the airframe is probably closer to 5-6 lbs presently, but we will come back to this topic once we have completed the priming and have done a final weight check.
@@DarkAeroInc a lot of that is the solvents that will evaporate as well! Excellent progress!
5:55 The fuselage contour looks excellent!
A rotisserie would help a lot with both fuselage and wing.
Prime, no problem splitting operations. However, when painting you will need to get it all in one go or you will have some dry spot issues and will need to prep the airplane a certain way for round 2. I’m sure you know this already just wanted to make sure! Thing looks sick all white!!!
Just needs a rolling jig that allows the fuselage to be rolled 45° or so each direction. Crack out that extrusion and get bolting!
"Thing looks sick all white!!!" Of course Mr. Swing would say this! Kinda like a Velocity, huh? ;-)
0:50 same thing with F1 cars,they are mostly carbon fiber chassis and the paint protects and removes some of the drag of the car (also sponsors of course), some teams like mclaren have removed paint from parts of the cars like bottom of surfaces and etc.
Too late now but there’s a product called xcr coating which has uv protection and a shiny clear surface it also self levels it’s used a lot in carbon manufacturing I run my own carbon company so thats how I know. If you ever make spare parts or new/updated parts maybe consider it as it would look awesome in visual carbon.
may want to look at a suspension cradle/crane for paint ... will allow painters complete under access and the ability to lower/raise the surface being worked on ... cradle may be set to rotate +-45
Paint will only make it go faster if you paint it RED!
I love following this project, the dark aero is looking more like a light arrow now! Hoping to see a cool paint scheme, keep up the good work!
It's great to see you are making progress! I come from gliding, so painting composite aircraft makes total sense. We use a PU or in older gliders UP gelcoat, and we use special templates for sanding to make sure that the profiles are shaped right after painting!
Is it possible to put the fuselage at 45 degrees? to get all the surfaces accessible at ±45° maybe that way will be easier
Fantastic surface finish @5:53. If that is just two coats, your molding was really great.
I love seeing this thing progress, excellent work, have you guys ever tried slicksand? Basically a polyester high build primer, it's been one of the best things I've found to get my composite stuff optically flat for paint, you can build it up so easily and quickly that I never even bother with filler nowadays, not on composite stuff anyway which is already so close to right.
Thank you for checking out the video and for the product recommendation! We haven’t used slicksand but we will look it up.
There is a range of in-mold vinylester sprayable primers offered by Hawkeye Industries. I believe it's called Duratek.
Duratek sands great but isocyanate polyurethane paints dont stick to it very well. Best is to use female tooling anx pull a painted part.
@@kwittnebel Yes. We spray it in our tools and let it cure/dry then infuse the parts inside the coating. It's recommended to scuff the part and primer before paint. Many customers use epoxy primer .
I noticed while getting back in to doing some body work that there's new primer fillers on the market that seem to be the new "thing". Basically it's a lightweight primer with more filling. Not sure if there's such a product that's good for aviation, but it looks like you're not using that zinc phosphate primer, so maybe automotive primer is OK? If so, I could see it being very useful in QC during production for the first coat.
I remember listening to a radio interview with a late war spitfire pilot - flying a griffon engine with clipped wings.
He was obsessive about aerodynamic cleanness. He filed down the rivets on his plane and filled in all of the rivets an smoothed over joints. After every flight he would clean and polish his plane etc. The result was that his plane was something like 40 mph faster than other Spitfires. (I'm stretching my recollection here, I reckon this interview was in the 90s)
He shot down a few Me-262s. They just didn't appreciate that he was almost as fast as them.
Anyway, moral of the story... I can totally see where you are coming from. Obsessing about aerodynamic cleanness can have huge payoffs.
I would love to build a scaled R/C version of this.
What about galvanic issues with the conductivity of carbon fibre ? We saw recently the feud between Emirates and Airbus because of the paint cracking, owing to the electrostatic characteristics of the carbon fibres.
The rotisserie idea is the best, just some other thoughts on how to paint. Look for an old Model 7 Binks (1-quart-size) suction spray gun, or to make your life much easier, go with a pressure "Spray-Pot," setup. FYI Spray-pots come in all different sizes, from 1 quart size, up to 20 gallon spray-pots, with air operated constant mixing / stirrer (BIG $$$$.) Another option is to go "Airless - Spray setup," that's what we used when painting 747 Wings, and be able to keep the entire wing paint wet during cross lap's.
As someone who has 25 yr's autobody experience, 5 year's as a painter 747's & 767's Boeing Aircraft, Everett, Washington, U.S.A., the word Epoxy and flexible is a non starter. Flexible = Polyurethane, Epoxy = rigid / kitchen stove top finish, read it and weep.
I cannot wait to someday order one of these kits. I've got a WHOLE LOT of saving up to do before then, though
Perhaps use a jig that allows you to rotate fuselage during painting.
Would it be possible to set the fuselage on a jig that allowed it to rotate (bank) 90' to make it easier to do the top and bottom?
Looking great and thanks for the update!
That's what I was thinking too (also for the wing)
On a rotisserie.
OOooo, vacuum infusion. I did some composite fab work a couple years ago on some fancy new Q/V band satellite antennae, and we used vacuum infusion for all our parts. I wasn't involved in quality control for the actual reflector surface, but I believe our tolerances were something like 50 microns, and as far as I know rework was basically never needed outside of issues caused by leaky bags, wrinkled layups, and thermal runaway. Now that i've done it that way, I don't think I'd ever use wet lay ups for anything but repairs and the quick-and-dirtiest of projects.
Looking very good! Waiting for flight testing! Are you going to use a pro test pilot???
The 3M PPS H/O system, provides a pressurised paint supply and is excellent for painting out of position.
There are both matte and gloss UV clear coats you could use. They can be sanded/faired and resprayed at the range of surface variation you are describing. I would use a filler made black with carbon dust and tape the joints off for even appearance.
And of course, the gel coat colour chosen, "white", helps to reflect the sunlight which would also contribute to keep the temperature lower inside the airplane, while on ground! The resin used on the skins, could also "suffer", just in case the gel coat was pigmented black, for instance... It could "melt" a little bit!
I have a question what about clear coating it? Couldn’t that’s leave the naked finish but keep the carbon epoxy protected?
We are experimenting with some clear coat options, but we haven’t tested it enough to be confident using it to protect flight critical structures.
I think you need a chassis rotisserie. They are made for cars (to access everything during restorations) but one could be adapted to a plane fuselage (without wings).
My friend made a straw bale house, a building where walls are straw bales coated with a plaster concrete. For marketing to show the interior of walls were actually made of compressed straw he put a small window in the plaster of one wall in a high traffic area. Can you leave a small area unpainted or coated with clear UV coating to show your plane is made of CF? I know this is just window dressing so to speak but it could change perception of the vehicle even slightly.
Hi guys thanks for your effort in revealing so much of your build. Thought...to paint fuselage a 'skewer' rig and rotate as you paint. Not a lot more work considering what you have already done.
use hand held card to block over spray at tail surfaces joint -
also lower air pressure with narrower pattern this area can help -
For painting any tubular section of the fuselage you really need to have 2x pyramidal triangular frames with pillow block bearings at the top so that you can attach an axle at either end of the fuselage & you'll be able to spin the plane 3t60 degrees for painting optimally in the best light as well. You could attach a temporary jig that attaches to the vertical stabilizer that has a horizontal pipe that fits into a pillow block bearing at one end & put an engine mounted jig that also mounts to a horizontal pipe that goes into the pillow block bearing.
very nice job ! would also look beautiful in a uv protectant clear as well!
Rotating the air cap will change the angle of the spray pattern to help get into tighter areas.
If you are going for laminar flow, I’m guessing you will be avoiding any spanwise stripes or color changes? Love the inflatable paint booth!
I'm fairly certain that flow becomes turbulent quite quickly at those Reynold's numbers.
@@acruzp there are laminar flow airfoils for RC airplanes with chords of just 20cm ...
@@marc_frank yes because the scale is smaller* and the* speed is lower*. Hence my use of the term Reynold's Number
edit: fixed spelling and grammar
@@acruzp and here comes the fix for the content:
Precicely because the Reynolds numbers of model airplanes are so small, combined with the fact that there are laminar flow airfoils for them, means that full scale planes must be able to have large sections of laminar flow, whose Reynolds numbers are gigantic, compared to those of model airplanes.
@@acruzp : that is very true - laminar flow is maintainable during the "positive pressure gradient" sections of a wing - it breaks down on the back end of the pressure gradients. (Often the "laminar aspects" of aerodynamics are moderately overstated. Many laminar flow wings tend to have very narrow AOA windows and rather unsafe behaviour - they rarely stall progressively)
I noticed that you didn't mention *heat buildup* from *sunlight* as a problem for carbon fiber parts.
Back in the days of glass-fiber-on-polyurethan-foam, that was a reason to paint parts white.
Is heat not a problem for a carbon fiber composite?
Did you think about maybe just wrapping the plane, Primer then wrap or just Vinyl wrapping alone.
One additional reason for painting the aircraft; solar heating of composite materials can weaken them. Gliders are usually white. to avoid warming them to floppiness
What is the weight of the paint and fillers likely to be?
For production I think a rotating jig that works like a rotisserie would work really well. Should just require two metal rod to serve as axles with a flange welded to one end that allows one axle to be bolted into the bolt holes for the rudder in the back and the other to the engine mount in the front with the axles in line with each other. A-frame stands for the front and rear with two bearing each at the apex of the "A" supports the axles. Oh, and by using two bearings on each stand, there are no bending forces in the flange and into the fuselage like there would be if a single bearing was used.
To make it easier to get the axles go through the bearings as the A-frames are moved over the axle, you could make the axle OD smaller than the bearing ID. Then thread the axle and put one threaded collar with a tapered OD on the axle first with the taper facing towards the bearings. Slide the A-frame and the bearings over the axle to the desired position along the axle. Then thread a second tapered collar onto the axle and screw both collars so the tapered end goes into a bearing until both are snug to take out the play between the axle and the bearings. This also serves to lock the A-frame to the axle.
Once both A-frames are in position, two "ladders" trusses made with square tubing and cross pieces at 45 degree angles could be used to lock base of the two A-frames together. I suggest this ladder structure so that an racking forces as the fuselage is rolled into the painting bay go through the ladders rather than the axles and the fuselage.
Once in the paint bay, thread a crank handle onto the end of each axle and you can easily use it to rotate the fuselage to allow you to paint every section from the optimum angle. No more having to stand on a box and stretch to spray the top or squat and try to spray upward to get the bottom, while still allowing the entire fuselage to be painted at one time.
Sorry if this is over the top, but I am a design engineer and I can't help but see design solution leap unbidden into my mind's eye.😊
Considering both decreasing the air resistance and increasing weight, what integral effect does painting have in terms of range capability?
Net neutral resultant.
My first thought was the need to lower drag but covering that uv sensitive epoxy definitely requires a coat. Don't want your plane falling apart in the hanger or even the air.
You guys have made such a fantastically light fuselage, it may not take much to create a jig that rotates the body along the longitudinal axis while in the paint booth. It may pay itself off in reduced spraying/sanding time.
happy I found this, I love experimental Aircraft, inspiring me to build my own from carbon fiber.
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You succeeded in removing a great deal of the Suck in painting composites in your crafting the high-precision molds.
A front line finish is still going to swallow many hours, but Dark Aero’s construction methodology will save many more hours.
It’s a big Win, overall.
Are there any paint guns available that can spray upwards? Even if the nozzle was tilted up at 45* that might be enough to reach the underside of the wing better and that corner under the horizontal stab would be a piece of cake.
The gun and cup system we used can spray while tilted upward. This is how we were able to paint the inverted surfaces. My complaint about the setup was that it isn’t ideal to crouch under the airplane to paint the underside.
There's also a heat element. Black gets quite hot compared to a white color.
just a thought.......for the Carbon look wouldn't a quality clear coat with uv protection... ie automotive paint, work ?
Awesome project. How did your Sherwin Williams fill bond filler at the stabilizers work out after painting. Ever see any cracks yet? In marine use, we tend to apply g-flex from west system. I guess the stuff you used is much lighter.
In the past I've heard one of the main reasons airplanes have been tradionally painted white is so that stress cracks can be more easily seen.
Are cracks not an issue with carbon fibre?
you could use a high end clear coat that could cut UV issues.
Great to see the progress!
You should be able to build a jig that lets you put the plane on a rotisserie style mount.
could you do some form of clearcoat/topcoat to protect the airframe while preserving the carbon-fiber look?
B17s were painted [70ishlbs extra weight] they did a paint, unpaint test to evaluate the weight saving and found that fuel consumption went up by 3% on unpainted airframes, the extra fuel to recoup the 100mile range loss was heavier than the paint.
It's going to take some getting used to the new look. Maybe Light Aero or White Aero now instead of Dark Aero?
Anyway, I love following this project. Happy Thanksgiving!
With black body filler would it be psooible to use clear paint to achieve a full carben/black look and retain the anti-UV properties?
What about gelcoat doing the "paint" being the first layer in the mold like they do with boats?
Are you going to top coat it black ?
Or is it the WhiteAero now ? :D
We will top coat it eventually, but we will probably fly it in primer first. Still deciding on the final color scheme. Thanks for checking out the video!
Science and perseverance. All the best gentlemen.
An option for a UV resistant clear finish would probably sell well. Carbon fiber is pretty cool.
Just like many car roofs are done. I don't see any aging in my six year old BMW carbon roof.
I work with cf on a hobbiest level and you can just use a UV stable clear coat but I'm sure there are also other reason you'd like to not make an airplane essentially all black
This video got me curious about a couple of things. I looked them up on line and it is evidently possible to powder coat carbon fiber which makes sense because carbon fiber is electrically conductive. Was powder coating a consideration among the painting options?
The second thing was lightning protection which led me to a website that said composite materials are poor conductors of electricity and they build airplane parts with an integrated conductive mesh to address this issue. What kind of lightning protection does your plane have?
Ailerons. They’re very handy for turning away from thunderstorms! 😂
They probably don't want to modify the structural integrity of the carbon as any for of electrolysis would do.
@@RobertsonDCCD yeah proly feels pretty dumb to experience death by misadventure.
Did you need to sand down any orange peel afterwards or did it all lay down pretty flat?
all about getting it done... if you can somehow get an acceptable product spraying just once, do it. it saves a lot of time and money, but takes more care and prep on the surface parallel to the ground.
i have heard of companies spraying their molds with primer, prior to layup.
then there is so much less paint prep work, because the primer takes to the mold, then the composite to that.
i would be the first to paint a carbon fiber airplane, for the reasons mentioned, and the reflectivity to minimize the solar heat.
1:34 is it that carbon fiber doesn’t require the sanding that foam/fiberglass does, or is it just the molds that removes the need whatever the material?
In this UK city theres no shortage of bodyshops are willing to paint carbon fiber panels
maybe a dumb question, but are there not uv blocking clear coat options as well?
could you hold the fuselage on a spit roast type setup and rotate it along the longitudinal axis for better access?
thank you for the video. can you share more details about the paint booth, maybe the manufacturer of it, and the ventilation system? thank you.
Great explanation, looks great.
Could you hang it from a gantry from the engine mount, or is that load too much over multiple hours.
Nice job guys! I'm sure you know already, and just didn't mention it. One of the main reasons plastic airplanes are painted white or a light color is because of heat. The difference between black and white in the sun is huge. Heat (oil and UV light) is an enemy of anything composite. ...composites don't work harden like aluminum, they just snap. Incidentally, you should put a coat of paint on the inside of the engine cowling for oil protection. It's not structural but it will prevent delamination and make it easier for repairs later. Cheers!
Would it put too much stress on the engine mounts if you used them to mount the fuselage on a rig that would allow it to rotate on it's longitudinal axis kinda like being on a rotisserie?
Use the Dekupps system that allows the paint gun to be inverted…expensive but worth it.
@MikePatey got a tip from a viewer about a micro filler he used on his Scrappy airframe. I can’t remember the episode but it’s green
Ten years ago, painting was completed on the first Boeing 787 in Everett, WA and it came out looking really slick. Little did Boeing or Airbus know at the time that the paint would at some point peel off from composite surfaces. Emirates got really mad at Airbus for their peeling paint and Boeing has also had its issues with peeling paint. 🤠
In the aerospace world (using pre-preg carbon fiber), the first ply against the mold surface is always a very thin sheet of resin rich pre-preg to give you a good surface without needing any filler. The aircraft in this video, even though you didn't use any filler, required a lot of extra coats of primer to get a good finish. This probably added 20-25 pounds to the weight of the aircraft.
It is amazing how hot a carbon skin gets in the sun. I had a carbon surfski (racing kayak) with a clear coated hull. Looked cool but got crazy hot in the sun.
Amazing work can’t wait to see this airborne! Might one one someday
Do you paint extra on the leading surfaces?
Do you worry about small wear points in the paint exposing sections of the airframe to UV?
Why don't you put the fuselage on a rotisserie to make painting easier?
Did you consider using horizontal and wing to body fairings like Andy Chiavetta created for Lancair Legacy racers?
Is this going to be sold as 'experimental'? Do you know when you are going to start taking orders? Great job!
Yes, this aircraft will be sold in the experimental category as a kit. We have started taking deposits for the kit. More information can be found on our website: darkaero.com/aircraft.
It's looking awesome already! Are you guys planning some design or just plain white?
Thanks Marlon! We've only had a few brief discussions on the final paint scheme so nothing is set in stone yet.