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      gebbw


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      Post #77582, posted on 02-12-2021 GMT-5 hours    
      Hi, when I found out this kit was available I just had to get one, the DC-8 being a favourite of mine. The plan is to build this as Air New Zealand ZK-NZC. I will attempt to model the kit with flaps down.

      I will be making adjustments based on sight using references found on the web, so a bit of creative license.

      Most of you will already have seen Tom's build here on Cafe, so I won't bore you with pics of the box and contents. I have been following his excellent progress and thanks to him I have been able to make some adjustments to my build and pick up a few extra skills (Thank you Tom!)

      Started with cockpit and front gear bay assembly. The finish in this kit is rough, but I find the plastic really good to work with, it is quite soft, so cutting and filing is easy.
      IMG_20210120_094859 by George Webb, on Flickr

      IMG_20210120_094919 by George Webb, on Flickr

      Cleaned up the tail section parts and I opted to join to the fuselage halves instead of assembling them as a peice. I think it is a better way to do it:
      IMG_20210120_164719 by George Webb, on Flickr

      IMG_20210120_165044 by George Webb, on Flickr

      I followed Tom's suggestion to strenghthen the join on the inside:
      IMG_20210120_165236 by George Webb, on Flickr

      Next was to get the cockpit piece glued in. It went in fairly well, with some minor adjustments to fit - Use you judgment here, and make sure you are happy how things line up. I did not bother too much with the interior.

      IMG_20210124_093757 by George Webb, on Flickr

      For the main cabin I with humbrol dark sea gray to keep it dark inside.
      IMG_20210124_162731 by George Webb, on Flickr

      Added some small lead fishing sinkers and glued with epoxy glue. This is where I made a mistake. I thought I had plenty of nose weight but no. This kit is quite heavy as I found out, and needs considerable weight in the nose. So I prised apart the cockpit and added more sinkers. Not sure how many I ended up with, so I hope in the end it won't be a tail sitter.

      IMG_20210124_162020 by George Webb, on Flickr

      AFter that was done, glued the fuselage halves together and set aside to dry.
      IMG_20210124_175714 by George Webb, on Flickr

      Initial thoughts on this kit is that yes it is no hasegawa, but I am enjoying building it. I think the kit maker has done a good job on the basic outline, but there are obvious flaws and mistakes. The trailing edges of the tail, stabilisers and main wings are on the thick side, so I spent some time filing the edges down a bit.

      The panel lines are quite deep, but in places where I sanded them away, it was easy to re-scribe being quite soft

      The main thing for me is that the shape has an DC-8 look to it that I am happy with. I can't say the same for my KMC 727 which I just can't get around to building that thing, until I can do something about that nose.

      Next steps
      Start work on separating the flaps from the wings. This means spending quite a lot of time searching the net for pictures for the basic flap sections and their layout so I can plan where to make cuts. Ironically, I have got some really good pictures by taking screenshots from a video by the New Zealand "Bring our Birds Home" team who's mission is to save former but derelict aircraft of Air NZ. They had some excellent footage of former Air NZ DC-8 ZK-NZC languishing in Manaus, Brazil. I really hope that they get to save her.

      George
      Auckland
      New Zealand

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      Tom Probert


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      Post #77584, posted on 02-12-2021 GMT-5 hours    
      Yes! Good man! It's great to see another being built.

      I'm especially keen to see how you get on with the flaps - this should be fun to follow!

      Tom

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      gebbw


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      Post #77589, posted on 02-12-2021 GMT-5 hours    
      thanks Tom, I am trying to keep up with your build, though its not a race of course!

      For the wings making the initial cuts was easy, just follow the panel lines..




      This is where I noticed that the flap track(?) fairing bulges on the lower wing did not line up with the distinctive flap hinge lines on the upper wing surface. I am not sure which of the underside fairings or the upper panel lines are in the correct place, so after some time trying to find decent photos showing the where the hinges were placed, I decided that the upper lines were more or less in the correct place, but the fairings underneath were not.


      What that meant was each fairing will need to be sliced off and saved to re-position it later.

      It is clear the panel lines have not been done with precision as they don't line up in several places, but none of this really a major problem. Particularly noticeable is the main flap hinged section (I don't know what it is called) which hinges up to prevent buffeting from the inner engines. On the upper wing the entire panel has been scribed by the mold designer too big I think. I used the lines from the lower wing as my guide as based on my reckoning, it was closer to what I could make out from the photos etc that I managed to find.

      George
      Auckland
      New Zealand

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      gebbw


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      Post #77600, posted on 02-14-2021 GMT-5 hours    
      Here are the flap fairing bulges after I cut them off. These were glued to 0.5mm styrene strip, so as to preserve the proper thickness after they were sawed off. Plus makes a better gluing surface for when I glue them back in place. I know the shape of the fairings is incorrect, but I was not bothered about correcting them.


      After the main flaps were separated from the wing, I thinned down the underside of each wing half. The plastic is quite thick and i took a bit of sanding to get it down abit. I decided not to make it too thin as I was worried about filing right through. It certainly helped with a better look.


      The next stage was create some sort of wing-spar/bulkhead inside the main wing. I could not find any photos of this section of the wing and I have no idea what they look like, so I made up what I thought would work. I found it best to measure up and cut the spar segments before mating the wing-halves together. I forgot to take pictures of this process, but this is the end result.

      Then it was a case of assembling the wing halves and letting them dry. Once that was done I fitted the spar segments. To provide a better appearance I used small evergreen 0.5 x 0.5mm (.020") square of where I assume the flap actuators would be. I was happy with the results.





      One thing I found was one wing seemed to be a bit 'fatter' than the other. It was quite noticeable after the wings had been assembled and the spars added. Indeed, the spar measurements where not the same, one was 1mm larger in height than the other. I think though that this will not really be a problem once the flaps are eventually installed, as you won't really see it.

      The inboard flap tucks into the fuselage, as seen in this video still (that's ex ZK-NZC by the way!)



      so I needed to cut a small section from the fuselage. Using the cut flap as a guide, I marked up the section that needed to be cut. Using a saw blade in my Xacto knife, it made easy work.



      The removed segment will be saved and glued to the flap, and I will fashion a piece out of evergreen sheet for the top part.



      For the hole that remained, I used evergreen sheet to create the 'box' and I was pleased with how it turned out.

      George
      Auckland
      New Zealand

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      Tom Probert


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      Post #77624, posted on 02-16-2021 GMT-5 hours    
      Looking very good, George - those extra spars will make the wing nice and solid, considering the amount of plastic you've removed.

      Tom

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      gebbw


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      Post #77625, posted on 02-17-2021 GMT-5 hours    
      Thanks Tom. They definitely helped.
      Here's some more pictures of the spars.



      Have been slowly working away at shaping the flaps for each wing. To get the shape of them made, I ended up cutting some sprue and glued it to the front side of the flap. When that was dry, I used Milliput to fill in the gaps between the sprue and flap part. Miilliput was perfect for this as it can be shaped quite well using a small blade and water to smooth it off.

      Unfortunately I didn't take any pictures of this process, but here are the inboard flaps after quite a bit of time sanding and filing. You might be able to see the sprue end that has been attached. I could not find many references to check the shape of the front part of the flap and how it is formed, so I just did what I thought would be close.





      Here are he main flaps after profiling their shape.


      To cut out the flap 'gates' I chose to use the panel line scribing from the top side of the flap to make the cut. As mentioned earlier in this build thread the lines did not line up very well for the underwing.

      These parts were sanded down and filed to shape. Next task was to glue strips of evergreen sheet to the cut faces to provide a nice smooth appearance. I cut several pieces of 0.25mm (0.010"))sheet and glued them, and when dry trimmed the edges and filed smooth. I repeated this process for each "gate" piece and the flap pieces.


















      That's all for now.

      George
      Auckland
      New Zealand

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      Jennings


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      Post #77653, posted on 02-21-2021 GMT-5 hours    
      You're a brave lad, George! Much braver than I, for sure. Just can't bring myself to tackle a Mach Deux monster.

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      Post #77658, posted on 02-22-2021 GMT-5 hours    
      Where are you getting the decals, or will you make them yourself? Are you going to use the initial TEAL colour scheme, later stars, or the final koru?

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      Post #77665, posted on 02-23-2021 GMT-5 hours    
      Those flaps are looking great, solid work there! I'm really stoked to see this one move along.

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      Post #77667, posted on 02-23-2021 GMT-5 hours    
      Quote
      Jennings :
      You're a brave lad, George! Much braver than I, for sure. Just can't bring myself to tackle a Mach Deux monster.



      Thanks Jennings. I'm finding it not too bad despite its problems.

      George
      Auckland
      New Zealand

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      gebbw


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      Post #77668, posted on 02-23-2021 GMT-5 hours    
      Quote
      pa747sp :
      Where are you getting the decals, or will you make them yourself? Are you going to use the initial TEAL colour scheme, later stars, or the final koru?



      Hi pa747sp, it will be ZK-NZC in the Koru Livery. I think it suited it so well. I plan to paint the stripes and koru, with home made decals for the titles etc.

      George
      Auckland
      New Zealand

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      Post #77669, posted on 02-23-2021 GMT-5 hours    
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      LH707 :
      Those flaps are looking great, solid work there! I'm really stoked to see this one move along.



      Thanks Merlin, they are slowly coming together.

      George
      Auckland
      New Zealand

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      Post #77670, posted on 02-23-2021 GMT-5 hours    
      Some more flap detail. To recreate/represent the flap track mechanism I found a few photo references on the net but only a few close up pictures of the real thing. So largely speaking I just made up what looked close enough. The idea was to make them look as close as I could to the few photos I found, but obviously there will be inaccuracies in my approach. But I think they will come out OK.

      First was to use to create a 'track' appearance for the top side using 5mm x 0.25mm evergreen strips. I cut out some notches on the ends to represent the linkage mechanism as best I could tell from the photos. These were glued to the upper side


      Using a piece of evergreen strip 6mm x 1mm, I crafted the slotted flap (not sure if that is what it is called) and filed/sanded it to an airfoil shape. Here is a picture of the main flap and the slotted flap




      The slotted flap will be positioned to sit under the track piece, but my method means the pieces will be very delicate. To support the slotted flap, I created little "actuator" pieces that fitted underneath. Again, my design is unlikely to be like the real thing, but the aim is to get good representation of the flaps when looking from above and not so much from underneath.

      My actuators where shaped to fit to the shape of the main flap, support the slotted flap, and provide a way to attach to the wing spar.



      And finally, this is the result. Note that in this photo I have not yet fixed my actuators to the curve of the main flap so everything appears to be set to 'takeoff'. Eventually I will be setting the flap to 'landing' but I will affix it all when I get to the stage of attaching them to the wing. The Evergreen strip 'tracks' provide some bend, and acts to support the main flap in conjunction with my actuators underneath. So hopefully once everything is finally glued in place it will be reasonably strong and look about right. (well that's the theory )




      I still have to make the inboard flaps so will start that next. Thanks for looking.

      George
      Auckland
      New Zealand

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      mathiemca


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      Post #77674, posted on 02-23-2021 GMT-5 hours    
      ...love your flaps.

      Cheers,

      Mike M.

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      Jeff Jarvis


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      Post #77679, posted on 02-24-2021 GMT-5 hours    
      Greetings!

      It all looks very nicely thought out and looks pretty good in execution. I can tell this is going to be a model of all models when you are done with all the neat little things you are doing with it! It seems Didier has provided his best canvas ever (so to speak) for the artists among us to go to town with. I can't wait to see these beauties when you are all done. Believe me when I say I am interested in every little detail that you talk about!

      Terminology, anyone? Just in case you want to know...

      The DC-8 flaps are best described and referenced as double slotted flaps. The piece where the inner non swept flap joins the outer swept flap is called a surfboard flap joint. The little thin airfoil shaped piece ahead of the main flap section is called a flap vane. It helps to direct airflow to improve efficiency and was invented by Douglas and first used on the A-26 Invader of WWII. The piece on the outboard piece of flap that starts to open up behind engines 2 and 3 after the flap extends to about 16-17 degrees is simply called an exhaust gate, precisely what it is for.

      The stepoff between the wing and vane, and the vane and flap is greater on the earlier model DC-8's, and is reduced (tighter) on the -62 and -63. Flap settings on the early ones are 10, 15, 25, 35 and 50, and on the -62/-63 are 12, 18 (some heavyweight -62 and all -63), 23, 35 and 50. If an early model is using 15 for T/O, the exhaust gate is faired, and if 18 is being used on a -62/-63, it is slightly opened. Those flappy looking blackish pieces you see where the flap tracks and pistons are located in between spoiler panels are not rubber but are actually metal. And, the really attentive among you would have noticed that there is one track for the inboard flap and three on the outboard flap piece, but on the ground, the very outboard part of the flap appears to be drooping slightly when the flap is retracted. This is not an optical illusion. It IS drooping. The reason is that the inboard flap has a hydraulic piston on its one track, and the innermost station on the outboard flap also has a hydraulic piston, but the two outer flap tracks are idler stations with no piston. They are only there to hold the flap in proper symmetry and inflight air loads fully retract the flap, whereas while on the ground, there is no aerodynamic load to do that, so they droop a bit.

      Some people believe the DC-8 has no leading edge devices. It has slots on the inboard side of each pylon. The slots open when flaps extend through 8-9 degrees and close when the flaps retract through 2-3 degrees. Slot position is indicated by an amber slot light, which is a disagreement light, meaning that the slots are not in agreement with the position of the flaps when the light is on. The light is out normally. When flaps are extended, the light comes on, then goes out, because until the slots open, they are momentarily in disagreement with flap position. When flaps are retracted, the light comes on, then goes out. If the light is on, you use simple logic to ascertain what it is telling you. Period. One oddity in this is that when a DC-8 has been parked for quite a while and is not powered, then an electrical power cart is applied, you check the volts and frequencies and they're good, so you apply power to the AC tie bus and immediately you get lights and noises. Usually an altitude alerter is heard immediately, and a few others. Anyway, you get rid of the bells and whistles, but the slot light is still on. The flap handle is up. The slot light is on and is not based on the position of the flap handle, but on the position of the flaps themselves. Sitting for so long, with no engines being run (or the aux hydraulic pump), the flaps are full down from bleed off of hydraulic pressure, so, if you clear the gear doors with maintenance or a safety observer, you start the aux pump, the flaps slowly come up and the slot light goes out when they do.

      As well, many people believe the DC-8 has no flight spoilers. This, as you might guess, is also not true. However, they are not full time as they are in many other airplanes. Since reverse thrust is used for emergency descents, the DC-8 flight spoilers are used for roll assist at slower speeds, so how are they activated? The max speed for extending the landing gear is 230KIAS. So, when the landing gear is extended, the spoiler pump automatically is activated and will link spoiler application to aileron displacement. Only the spoilers outboard of the sweepback change are flight spoilers. Rarely will you ever see the ailerons displace far enough to see the spoilers extending though. In 7,000+ hours in the DC-8, I only saw it once, and that was as a passenger in back on a Canarsie approach to JFK.

      I loooove the DC-8!

      Best regards,
      Jeff Jarvis

      God's "Curse" to aviation!

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      pa747sp


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      Post #77681, posted on 02-24-2021 GMT-5 hours    
      Quote
      gebbw :
      Quote
      pa747sp :
      Where are you getting the decals, or will you make them yourself? Are you going to use the initial TEAL colour scheme, later stars, or the final koru?



      Hi pa747sp, it will be ZK-NZC in the Koru Livery. I think it suited it so well. I plan to paint the stripes and koru, with home made decals for the titles etc.



      I look forward to seeing it. BTW, did you used to be an engineer for NZ?