KH T-6/Harvard Kicked Up A Notch: Apr 14/20: Finished!

[chuck540z3]

2 hours ago, DerekB said:

Great to see you working on this subject Chuck, I have four of these kits, all destined to end up somewhat modified. So I'm very interested to see what you can do with this one. Great choice of subject too!

 

I'm always amazed to see kit manufacturers coming out with so many inaccuracies in their kits... some are understandable if the subject is rare or poorly documented. But with so many Texans and Harvards around, the mistakes in this kit are unforgivable!!

 

The tail-wheel detail by KH is stupendously poor, and I noticed your solution based on Max's fine work. Since I have 4 of these kits, I've been working on a 3D printed solution to the tail-wheel "knuckle", see my photos below for how it should look:

 

Also, the amount by which the tail-wheel protrudes from the fuselage is due to the fuel and crew load, not related to the position of the tail-wheel. Since the tail-wheel is sprung with an internal pneudraulic cylinder, if the fuel tanks are full and there are 2 pilots on board, the tail-wheel doesn't protrude much at all. In the photos above you can see that with no load on the wheel it is fully extended.

 

Cheers,
Derek 

 

 

Thank you Derek for all that great info and pics on the tail wheel!  The last part would explain why the wheel protrudes sometimes and not others.  Extra weight would explain why pics of a Texan taxiing to the runway usually has a low profile, while a parked Texan/Harvard, which usually has the wheel forward due to being pushed backwards into a parking stall, has a more pronounced profile with much less weight.

 

My effort to replicate this tail wheel contraption isn't great, but it's a lot better than nothing and once painted should look the part.  I suspect in time this part will become available in resin by somebody, along with many other corrections I'm about to find out about!  Using Max's guide, I have Mustang wheels as replacements, but a correct set of Texan ones would be most welcome.  Barracuda maybe?  Time will tell.

 

Cheers,

Chuck

[chuck540z3]

January 17/20

 

Following Max’s (Mozart) build of his Rhodesian Harvard, he fixed the big ribs on the rudder and elevator using Archer rivets.  Thanks for the tip Max.

 

First, this is what they look like unaltered.  Way too high...

 

 

 Let’s look at a few pics of a real elevator and rudder.  Note the fasteners behind the fabric, with what looks like fabric tape covering them as reinforcement.

 

 

Also note that the trim tabs on both have fairly large gaps on either side.

 

 

So like Max, I sanded down the ribs until they were barely visible and added the Archer rivets, which are from the AR 88014 “Various Scales” set.  Fortunately, by cutting each row of rivets in the center, the resultant width is just about perfect to cover each remaining rib.  I also opened up the trim tabs with a razor saw.

 

 

After adding Archer rivets, I normally spray the rivets with Tamiya clear acrylic X-22 to both seal in the rivets, but also to hide the decal film, which always seems to be present no matter how much Microsol you use.  Here’s an example from my last build of the Kitty Hawk F-5E, which has no raised rivets over the engine area, which is a characteristic feature of this jet.

 

From decal film…

 

 

To a few coats of X-22…..

 

 

Then painted.  Decal film edges are 90% gone.

 

 

Now back to my Harvard.  Since there really is a tape-like covering over the fasteners, I just sprayed  a light coat of X-22 to seal in the rivets and make them tougher, but not enough to remove the decal film edges.  Here’s the top, with every rivet mark repunched and every panel line re-scribed after sanding, like the rest of the model.  That curved light colored smiley on the right came like that right off the sprue, but it doesn't appear to be raised so that it will show up again after paint.

 

 

And the mirror image bottom.  I’m going to leave all this stuff off the fuselage until I get main wings glued on, because I can tell that I will be flipping this model over and over to make everything fit and I don’t want any more junk getting in the way.

 

 

Next up the wings, with revised landing gear position and full brass Eduard landing flaps to add some interesting detail to the back.

 

Cheers,

Chuck

Edited January 17, 2020 by chuck540z3

[Dragon]

Fantastic work!

[Troy Molitor]

A much better representation.   Well done.   

[dodgem37]

Great problem-solving.

 

Sincerely,

Mark

[Thunnus]

Excellent update!  Thanks for showing us how the Archer's rivets work!

[chuck540z3]

Thank you very much everyone!

 

39 minutes ago, Thunnus said:

Excellent update!  Thanks for showing us how the Archer's rivets work!

 

Thanks John.

 

Just in case there is interest, below is a cut/paste tutorial from my F-5E build that might be worth repeating here for those who haven't used Archer rivets before:

 

Archer Decal Rivet properties:

 

1)  The wider the decal film, the stronger the chain of rivets, but the higher the chance that it will show under paint, no matter how much decal softener you use.   Checking other builds using this product, you will see what I mean.

 

2)  The narrower the decal film, the more fragile the chain of rivets, which often break apart, but it will not show as easily under paint.

 

3)  Rivets applied to curved surfaces should be done in short chains, for ease of handling.

 

4)  Even single rivets can be applied successfully, so if you bump off one or two, repairs are easy.

 

5)  Like most decals, these rivets come off the backing better with very warm water.

 

6)  If you don’t like what you’ve done, the rivets can easily be removed with a finger nail and you can start over.

 

7)  Archer rivets come in many different sizes and spacing, so I like to have a variety of them on hand.

 

8)  The raised rivets are not always perfectly round, but after paint, you’ll never notice the small imperfections.

 

9)  As long as you keep the decal segment wet, you can move it around for a very long time.  Even after using Microsol decal softener, you’ve got more time to play with it than a regular decal.

 

10)  These rivets are quite expensive at ~ $22/sheet!

 

Application:

 

1) The surface should be super smooth and clean of any debris and oil from your skin.

 

2)  Cut a long and thin strip of rivets off the sheet, then into shorter chains to be applied individually.  If you’ve got a flat surface free of detail or curves, you can apply segments of an inch or more.  Curves and detail require shorter segments.

 

3)  Soak the segment in very warm water like any decal, for at least 5 seconds, then place it next to where you want to apply it for another 30 seconds or more.

 

4)  Using a soft paintbrush, push one edge of the decal film off the backing, let it attach to the surface of the plastic, then push the rest of the decal off the backing.  For longer segments, you can push one end off the backing by sliding it in one direction, then grab the backing and pull it off, leaving the entire segment behind on the plastic.  If it breaks, don’t worry about it.  You’ve got lots of time to get everything back together.

 

5)  Using Microset (or plain water), re-wet the segment so that it floats, then move it into place.  Using a paper tissue, pull the water away from the edge of the segment without touching it.

 

6)  When you’re happy with the decal placement, using another soft brush dedicated to decal softener, apply some Microsol in very small dabs to tack it down.  If the decal  moves, you’ve still got at least 30-40 seconds to move it around without fear of destroying it.

 

7)  For the next decal segment, apply it as above, but somewhere else!  If you try to apply the next segment next to the one drying with Microsol, you will likely move it and create a mess.

 

8)  When the first segment has dried a bit (~ 5 minutes), liberally apply more Microsol to it over the entire decal.  Unlike regular decals, you can’t wreck it by applying too much softener.

 

9)  In a bit of an assembly-line process, apply new decal segments while applying more Microsol to others, keeping new ones away from old ones.

 

10)  If you knock a single rivet or two off, don’t worry.  Just cut off a replacement and apply it in the gap.  The strength of the rivet to plastic bond is mostly under the rivet and not beside it.

 

11)  When you are done and everything looks pretty good, add yet another coat of Microsol to everything, all over again.  You want to nuke the decal film into oblivion as much as possible.

 

12)  When everything is clean and dry, I like to apply a good coat or two of Tamiya X-22 acrylic clear gloss to seal the rivets to the plastic, but also to smooth out the fine lines of the remaining decal film.  I use about 2/3’s X-22 and 1/3 Tamiya lacquer thinner, which sprays very fine.  Future/Pledge works just as well, but is softer than X-22 and harder to sand later if you have any imperfections.

 

13)  Paint as usual.

 

 

 

Hope this Helps!

 

Chuck

Edited January 17, 2020 by chuck540z3

[Rocat]

Great progress and really interesting tips, thank you.

[chuck540z3]

January 21

 

Shortly after I started this build in November, LSP_Kevin pointed out that the main landing gear is too narrow and should be made wider.  He pointed out this article by Mike West on how to fix it:

 

Correcting the Kittyhawk Texan Landing Gear Position

 

This procedure looks really tricky and I’m not sure I could do it without making a big mess, so I tried to fix it another way.  When trying new things, sometimes I win and sometime I crash and burn, but it’s always fun trying.  I think I won this time, so let’s look at the problem a bit closer.

 

This is where the landing gear is located.  Note the gaps on either side between the gear legs and the gear bay opening.

 

 

 

 

And this is what it should look like, with very little for a gap….

 

 

 

 

Here’s the problem.  That gear leg receptacle needs to be moved outwards and replace that double rib just to the left of it.  The problem is that the receptacle has a very specific angle from front to back and side to side, to keep the landing gear straight, so cutting it and moving it can have consequences if you don’t do it perfect.

 

 

 

 

If you could recreate the gear receptacle, you could place it wherever you wanted to.  About 8 years ago a modeling friend showed me a new Japanese polymer product that is fairly rigid plastic when at room temperature, but in boiling water (or other heat source) is becomes very pliable and is perfect for making molds.  I don’t know the name of it since all labeling is in Japanese, so here’s a pic.  I hunted around in Google and came up with another product that looks similar by a company called Polysis that they call “Haplafreely”.  I’m sure there are many other types now available.

 

 

 

 

So I rolled up a couple blobs of the stuff and immersed it into a cup of boiling water and let it sit for a minute.

 

 

 

 

When warm and pliable, I then pushed the blobs over the parts I wanted to replicate, let them cool for a few minutes, then pulled them off.

 

 

 

 

The mold detail within was excellent and I trimmed off the excess plastic.  Last time I used this product I was making small parts that had no real stress applied to them, so I used Tamiya Light Sensitive Putty.  I need something much stronger this time, so I used Gorilla Clear Epoxy that comes with two glue syringes for the epoxy and the hardener.  You apply an identical amount of each to a hard surface where you then mix them thoroughly together, which will stay in liquid form for up to 5 minutes.

 

 

 

Using a small microbrush, I carefully filled each mold with the epoxy, being careful to not introduce air bubbles.  If air bubbles do form, you can poke them with a toothpick in a plunging motion, but you need to do it fast before the epoxy starts to harden.  Note the epoxy is raised a bit over the top (at the bottom of the part), to ensure the void is completely filled.

 

 

 

 

24 hours later, you can pull the epoxy out of the mold, which is now very hard and won’t stick to the polymer.  I then sanded the bottom flush and trimmed any flash.  Voila!  A new landing gear anchor point that is identical to the original.  The epoxy does not shrink and although very hard, still retains a slight bit of plasticity so that it won’t break under stress.

 

 

 

 

I then cut out the two ribs at the back and rather than completely remove the old anchor, I retained the back for added strength where the new part was glued in using CA glue, creating a solid mass.  The new anchor is lined up exactly like the old one as shown with the red line.  Note that I was able to retain the pins and angle detail at the front, which Parts F21 and F-22 are glued to, without a lot of sanding mess to clean up.

 

 

 

 

Part F-22 and the gear leg dry fit into place.

 

 

 

 

And the new landing gear alignment, which is just about perfect in all directions. 

 

 

 

 

That’s about it guys.  A little experiment that went well for a change, which is super easy to do.

 

 

Cheers,

Chuck

Edited January 21, 2020 by chuck540z3

[LSP_Kevin]

Very clever solution, Chuck! And that's close to how I would have done, should I ever build this kit again (except I'd use plain old casting resin to make the part).

 

Kev

[TAG]

That polymer molding material is called Oyumaru in Japan, there's a grip of tutorials on Youtube and you can find some pretty cheap deals for it on ebay. This being the scale modeling industry however, there's a Spanish company called Green Stuff that rebranded it as "Blue Stuff", which sells for significantly higher prices than oyumaru (naturally...) but I guess is more readily available at your LHS if you don't live in Asia. Either way, it's really good stuff.

 

Epic work as usual, Chuck!

[Chek]

Chuck referring back to your tail control surfaces, I'd suggest varnishing strips cut from hand rolled cigarette papers laid over the rivets. That would help disguise their rivetty nature and simulate the knots under a fabric strip slightly better. Slight unevenness where the varnish locally tensions the strips over the rivet heads as they dry will also help sell the illusion.

Edited January 21, 2020 by Chek
spelling

[levier]

This is exactly what I enjoy sbout this community.  Thanks you all!

[chuck540z3]

11 hours ago, LSP_Kevin said:

Very clever solution, Chuck! And that's close to how I would have done, should I ever build this kit again (except I'd use plain old casting resin to make the part).

 

Kev

 

Thanks Kev.  Fear of the unknown I guess, but I've never used resin before.  Everything I can find on-line looks like you need to buy a lot of resin in order to make a couple of tiny parts.  In any case, I like the epoxy parts I made because they are very rigid, yet flexible enough to never crack under normal landing gear stress and weight.

 

8 hours ago, Chek said:

Chuck referring back to your tail control surfaces, I'd suggest varnishing strips cut from hand rolled cigarette papers laid over the rivets. That would help disguise their rivetty nature and simulate the knots under a fabric strip slightly better. Slight unevenness where the varnish locally tensions the strips over the rivet heads as they dry will also help sell the illusion.

 

I like your idea, but maybe not with cigarette paper, since they will likely look too thick for scale.  I'll try a few things on a test piece and see if I can find a winner- or just leave everything as is.  Sometimes less is more.

 

Thanks for the tip.

Chuck

[Thunnus]

Thanks for the detailed instructions on the Archer rivets... great info!  And the wheel well modification is just fantastic.  I've always wondered what it would take to mold and cast a simple part and you've laid out a complete tutorial!  Wonderful!