Harbour Air DHC-3T Vazar Otter (Single)

[Brandy]

That's a much better nose job than MJ had, you're in the wrong profession!

 

Ian

[hendie]

  

On 6/5/2025 at 5:57 PM, CedB said:

More coats of primer? That’ll be about twenty now? No wonder you run out…

 

The MRP primer is decent stuff but the SMS primer definitely had a far greater coverage power. When it's finally back in stock I'm going to invest in a few bottles.

 

I think I'm in SWMBO's bad books for some reason so probably very little in the way of modeling this weekend, however I do have one significant update to share.

Over the past few days I've been working on this arrangement.

 

 

I managed to run the first test print of the mounting struts...

 

 

The struts are far too long but I'm calling this a success as the biggest challenge on these was getting all 4 mounting holes positioned correctly in relation to each other in that wonderful environment called 3D space. Since I constructed the strut model parametrically, in theory all I should have to do is adjust the height of the construction planes relative to each other and the model should update itself without any other user interaction from moi.

That's the theory but this is the real world so we'll see what happens once I'm back on track with SWMBO.

 

It goes without saying but I'll say it anyway - these are a lot more accurate than the kit offerings and I've tried to replicate the actual fixtures while still maintaining some strength in the parts. (This was all done in a rush this morning so there's absolutely no cleanup of the parts performed other than snipping off the supports.)

 

 

I think there's room to thicken up the front strut and still look in scale. The rear strut is a different beast. It's only 3mm wide and about 1.5mm at the thickest section of the aerofoil shape. That means it is always going to maintain a high degree of flexibility due to a combination of the geometry and the material properties.

I have a plan B in the dossier so I'll bring that into play if need be.

 

The 1:1 

 

 

Then my version

 

 

Now that I have a touchy feely prototype I'm in a much better position to update the model to better represent the 1:1.

My to do list involves moving the mounting holes on the floats forward by 2mm and reducing the height of the struts by around 10mm. It's all going to be guesswork I'm afraid as I cannot find any information pertaining to the float/strut height so all I have to go on is reference photos.

Regarding that - as far as I can ascertain the rear strut is vertical while the front strut is angled forward slightly (but not by much) from the fuselage to the float. Thoughts?

 

[Brandy]

Difficult to see from the pic above, but I'd tend to agree. They are definitely a good starting point and shouldn't take too much tweaking to get right.

 

Ian

[perdu]

Thoughts?

 

OK, at first sight it seems as if you have the strut mounts in the wrong position, but hah!

 

No, the strut mounts look right but the under-fuselage strakes come forward too much, they should stop/start at that sloping construction line shared by the double row of rivets, the strut mounts and the wing leading edge (which we understand to be compromised a bit because bad kit design)

 

I love the upper part where you have included the fuselage stiffener/mount part ready for glueing straight on, brilliant and should add stiffness when the lengths are right.

 

Thoughts?

 

Marvellous.

[Brandy]

1 hour ago, perdu said:

should add stiffness when the lengths are right.

CED!!!! @CedB

 

Ian

[MrB17]

You are doing exceptionally well figuring out the floats Alan. Depending on the float manufacturer, there are at least 3 distinctly different rigs. Some have a flaired fairing on the front struts, wider at the bottom than the top, some are a constant airfoil section and some are almost tubular. I think yours is the latter. The distance between the floats determined by the spreader bars is the same. So what you have done so far looks really good. The hardest part is rigging them so they are squared. You might consider making a cardboard jig to help, unless you have 8 arms.
I’m not sure if you have been to this website, but it’s a work of passion by a few Otter experts.

http://www.dhc-3archive.com/DHC-3_Master_Index.html The technical drawings section is mostly general arrangement diagrams, so they aren’t reliable, but there are hundreds of photos of just about every Otter built, in most of their various configurations and operators from original to current. If you message them they might be of great help if you need anything more.

 

Cheers

 

Jeff

 

[81-er]

I think you're off to a really good start there, Alan  

 

James

[giemme]

11 hours ago, 81-er said:

I think you're off to a really good start there, Alan  

 

James

Or even a great start!

 

Ciao

[heloman1]

Great work on the floats and struts Alan. Re the rear strut, could you not engineer a slot in the rear face to allow a piece of wire to be inserted? It could go into the fus and the float to give a rigid support. JMTPW!

 

Colin

[hendie]

Back again I'm afraid.

 

10 hours ago, heloman1 said:

Re the rear strut, could you not engineer a slot in the rear face to allow a piece of wire to be inserted?

 

Great minds think alike Colin.  I had already printed a set with the slot last night to try out the concept. I used a 0.9mm wide slot with a piece of Ø0.80mm brass rod inserted. I can throw some filler over that and smooth it over and no-one will be any the wiser.

 

 

In other news, yesterday I removed 7mm from the overall height of the struts and it's looking a lot better overall.

 

 

Once the cross braces are glued in place it adds quite a bit of stiffness. I printed the cross braces vertically and that allowed me to have a Ø0.85mm hole all the way through. A couple of pieces of brass rod are inserted into the cross braces to add some strength

Once the rigging is added - and there's lots of it! - I reckon it will be fine.

 

 

I know it's hard to see in these shots but I've added pulleys and brackets on the cross braces in anticipation of the rigging to come. I've also added some pulleys and greeblies to the floats so they're undergoing another print run as I type. Eventually I'll get there... I think I've caught everything now.

 

 

Even just a dry fit shows that things seem to be aligning well. No doubt I can mess that up when it comes to adding rigging. 

 

 

However, there is still a bit of work to be done.  Removing that 7mm made it sit much better but I think I'm still too high at the rear. 

 

 

My best guess is that it is sitting somewhere between 2mm and 3mm too high, so I'm running another batch of strut prints with 2mm removed, 2.5mm removed and 3mm removed.  If all goes well, one of those sets will be the magic number.

 

While all the printing was going on I added some more greeblies to the fuselage. This time the hand hold above the cockpit as well as some bases for aerials (2 up front and 1 down the rear...)

 

 

The plan is to fit some Ø0.3mm wire pretending to be aerials.  Tested out with some scrap wire and it works. I think these will be the very last things added as I'm bound to either break 'em off or take my eye out with them.

 

 

Yet more primer added. It's looking better but if I'm honest, I'm not completely happy with the front seam.

 

 

I think I need to sand the entire surface of the printed part, and not just the area around the join as that just creates a little dip which really catches the light in a bad way. The seam on the other side is much better and doesn't need much in the way or work at all. 

 

I'm wondering though if the hill is worth the climb as that seam is going to be all but hidden when the door is fitted in the open position. Am I going to make it better or worse if I try and eliminate that seam?

 

 

I'll figure that out over tonight. If I'm going to do it, I may as well start before I throw any more primer on the beast.

 

 

 

 

[marvinneko]

If you put something under the backs of the floats to level them out (as they would look with an engine pulling the nose of the plane down) you'll get a stance you can compare to a pnoto. I messed around with my Norseman a bit like that.

[heloman1]

Neat work with the struts and floats Alan. I assume, you'll be printing working turnbuckles to add to the bracing wires...

 

Colin

[81-er]

That's coming along really nicely, Alan. I think the seam is ok, especially as it'll be hidden behind the door anyway

 

James

[giemme]

16 minutes ago, 81-er said:

That's coming along really nicely, Alan. I think the seam is ok, especially as it'll be hidden behind the door anyway

 

James

I very much agree with James here, Alan. I'd really leave that seam alone...

 

Ciao

[CedB]

I'd thought about the rod stiffener too; great minds and all that  

 

Er, fnaar!

 

Nice floats. Are you going to play with it in the bath?

[hendie]

7 hours ago, CedB said:

Are you going to play with it in the bath?

Now now Ced... no need to get personal!

 

 

Nothing worth photographing today I'm afraid. Just printing off some more parts and test fitted the shorter struts. The shortest set look best so I'm going with them.

Also, primed up some spare floats and started testing coloring them in.

Sprayed more white on the fuselage and that seam is looking better. I think one more coat should suffice.

 

Ba k when there's something worth showing.

 

 

[perdu]

I agree about the seam, looking at various DHC airframes joining panels isn't something the seem very assiduous about and as you say it's behind the door anyway.

 

Ced, I am shocked, no surprised at you mate.

 

[Troffa]

I'm so late to this party, it cannot even be considered 'Fashionably Late', but I am delighted to have arrived before the end- what amazing modelling- the commitment to accuracy, the attention to detail and the multitude of techniques and methods on display is simply awe inspiring.

What a fabulous hobby this is, especially when practitioners such as yourself share your work.

 

Thanks to you Sir!

 

Troffa

[hendie]

Thanks for all the kind comments folks - much appreciated.

 

It's getting to that stage where I feel I am finally achieving something and things are actually moving forward. I started this back in APril but it feels like it's been going a lot longer than that.

I haven't heard Giorgio complain about paint recently so no doubt he's about to pounce, so in a pre-emptive operation I colored in some propellers. I only need 3 but getting those stripes correctly positioned against a radiused tip was challenging. 6 done and I'll pick the best 3.

 

 

The floats got a coat of gloss black in anticipation of being aluminized. They look very rough here but I've done some testing with my spare floats and they turn out okay. That faceting that you can see on the sides was unintended but once painted up it gives the impression of tin-canning so I'm quite happy to leave them as is.

 

 

You may not notice in the above shot, but I have removed the nose from the float and also removed a portion of the back face - this allows me to print the floats (essentially a tube shape) without getting any excess resin trapped inside. The nose cone and the rudder can be attached when the time comes.

Over the past week I've been working on various odds n sods and the rudders were one of those items. Not a very good photo is it?

 

 

This might be a bit better. Glorious macro! That rudder is only 0.3mm thick so is very fragile. Again, these will be one of the past things fitted as they will be very easy to break off, hanging off the back end as they are.

 

 

After all that, the fuselage was given a last coat of white and then clear glossed. That seam is still there (obviously) but hardly noticeable now.

 

 

A selection of doors also got gloss coated. I had to do these separately as the doors will be one of the last things to go on to finish this build, and I won't be able to do any glossing after that since doors will be open, windows will be visible etc.

 

 

I gave the spinners a coat of cheapo pen chrome. The one on the left has been clear glossed and looks terrible in comparison to the one on the right. If I remember correctly, I think the last things I chromed were left for days to cure then I only handled them with nitrile gloves on and the finish stayed intact - I think that will be the plan going forward.

 

 

The fuselage had been left overnight to let the clear gloss harden up and with that job done it was finally time to fit the cockpit furnishings, not that you can see much once they're in. 

The instrument panel went in first so I could use that to get the seats positioned correctly in relation to the controls.

 

 

 

Like so... 

 

 

After all that - very nerve racking stuff - I needed a change. WHat better than to start adding decals?  Well, there's lots better than adding decals but it's another job that needs done, one way or the other.

First decals on - can you see them?

 

 

Yes, those three semi circular bits under the three sticky-outy bits (fuel cap and who knows what else). There's another semi circular portion of that decal to go above the caps but I'm letting those halves settle in first. Believe it or not but those are left over decals from my DB5 build - they're the labels for the wheel knock-offs. Just a tad on the small side but I think they work okay.

THen some labels on the starboard side, and some aluminum paint on the door handle. Again the decals are a bit large but they're all I could find in  the stash, and this is the side that will face the back of the cabinet so... 

 

 

Aaaand... here they are all done, with the caps colored in. That doesn't look too bad at all. I'll call that a win.

 

 

More test fitting in order to avoid doing anything constructive and I noticed this... there's a definite difference in shade between the fuselage and the nose piece. Oh well, another coat of white for the nose and another gloss coat is in its future.

 

 

A job I am not looking forward to is masking and painting up the floats - that detail on top is going to be a nightmare.  First though, the top surface needed a coat of flat black. Mr Color Black Grey to be exact. I'd like to have carried on with these I've ran out of the correct coloring in fluid and am waiting on some arriving in the next day or two.

 

 

 

This week I got around to printing out the wings I had modelled some weeks ago. Boy, are they heavy. Very heavy, so heavy in fact I don't think the fuselage, or the float struts will take the strain of all that weight.  Other than that, they're fine 

 

 

I've since gone back and cored out the wings to save some weight, and I'll see how that compares when they're printed.

Then, just as I think I'm getting somewhere I take a closer look at the kit parts. Oh dear.

There's just so many things wrong with them that I had to go and model a new set. For example, the kit has recessed flutes instead of raised. The trim tabs are wrong and the tip shape is also wrong. It was easier just to design and print from new than it was to try and fix the kit parts.

 

 

That will allow me to pose the aircraft with the elevators slightly drooped, which is how they are often seen when parked... or should that be docked? Sitting still then!

 

 

I'll need to redo the tailplanes as I have the sweep angle a touch on the light side and they need to be swept back just a fraction more. That's an easy enough fix though.

 

 

Ah, it's the weekend. Enjoy.

 

 

[MrB17]

Nice work Alan! It’s already a masterpiece and it’s not even finished…there should be a ceremony for the grand unveiling.

 

Cheers

 

Jeff

[81-er]

I think you're going to have to have a tally up to see how many (few?) of the kit parts you actually used when this is done, Alan. Beautiful work again, as with every update. 

 

James

[Brandy]

Funny how, once you have a 3d printer, so many kit parts just need "a quick replacement"!

 

Looking good for it though!

 

Ian

[CedB]

Excellent progress hendie, she's looking great!

 

How many doors?   

[giemme]

Glad to see this build is still mainly OOB  

 

Excellent progress, even with a smear of paint      

 

Ciao

[perdu]

Good stuff H, I'm loving the spinners