1/72 DHC-4 Caribou prototype

[72linerlover]

Hello everybody. This is my first entry.

A very kind guy of the dhc4and5 website provided me some information about the prototype that differs from the production aircraft for few key featrures.

- shorter fuselage, approx 1,1 meters

- different and shorter exhaust staks

- absence of fuselage strakes.

Other differences will be explained during the build.

First I perepared my own glue by dissolving some sprue in acetone and lacquer tinner.

 

Then, began to study what have I to do with the exhausts, but not yet sure about.

 

Here is where the fuselage has to be shortened.

 

Last is the fuselage strakes removal. Some preparation to avoid damaging too much the panel lines

 

Some sanding and restoring the panels after finishing.

 

So, that's all for the moment.

Thanks for watching.

Regards

Euge

 

[Trojan Thunder]

Will be following Euge, I was not aware that the prototype had a shorter fuselage.

 

Are you going to fix the wing dihedral and engine position issues of the kit as well?

[72linerlover]

20 hours ago, Trojan Thunder said:

Will be following Euge, I was not aware that the prototype had a shorter fuselage.

 

Are you going to fix the wing dihedral and engine position issues of the kit as well?

Thank you Ray, for your comment.

I know I'm facing some surgery for the wing to correct the dihedral. The problem is in the outer section and I have a plan.

As reguards the engines, I'm going to replace them since they are 18 cylinders in the kit, while they should be 14.

I have some left over engines of a DC-3 that match the cowling dimensions.

I'm not aware about the position of the engines you mention. I am afraid! Waiting for some suggestion from you.

Regards

Euge

[Trojan Thunder]

Euge, here is a pretty good build thread showing some corrections made to the kit. I forgot about the cylinder count.

 

It was stated in that thread the engines sit slightly more proud of the wing than the actual aircraft. In the linked thread this issue was not rectified. It also shows how the dihedral was fixed.

 

BTW I have Caribou to build as well, as an RAAF aircraft, so I am interested how you go with your prototype build.

[72linerlover]

Thank you Ray.

That guy did a very nice job. He managed the dihedral issue just like I planed to do.

I suspect that, after the prototype stability problem, the dhiedral of the production aircraft was rised of some degrees.

See the two linked pics.

link1 - prototype

link2 - series aircraft

Not easy to find similar views. You have to look only at the upper surface to have the right impression.

Anyway, the kit parts need to be corrected in both cases.

No major surgery for the engine position: I started the kit with the firm intention to keep the build simple and it already is more complicated.

Regards

Euge

 

[72linerlover]

Hello everybody.

Spent some time for the engines replacement.

 

New firewalls: they have to be 4 mm further back as the original, since the engines are longer.

 

So I prepared 3 spacers to fit inside each cowling

 

Test fit of the engine: it seems to work.

 

Next task will be to find the proper shaft and center all parts.

Thanks for watching

Regards

Euge

 

 

 

 

[72linerlover]

Hi everybody.

After some holidays in Slovenia (beautiful land, BTW) I came back to the bench preparing some interiors for the Caribou.

Cockpit in construction

 

 

In order to put the seats rails in the correct position I started working on one of them, with the hope to make the other one as much as similar.

 

Not great detail, but something more realistic as the parts in the kit (I hope)

 

 

Thanks for watching

Regards

Euge

[Sebastijan]

Wonderful work so far, Euge!

 

OT: If you ever come back to holiday here, let me know and I'll buy you a beer ;)

[dnl42]

Nice work! 

[Trojan Thunder]

Engine and cockpit work is very nice Euge.

[72linerlover]

Hi, everybody.
After a long absence from modeling and from the forums I had the chance to come back to the Caribou.

So I managed to almost complete all the bits for the cockpit.

A thermoformed coaming, starting from a wooden master.

 

 

 

 

 

Also added some frames inside with styrene strips and primed.

 

Since I was at with the primer, I shot some also here

 

And here are the parts I have to glue together:

the central sliding consolle

the control columns

the elevator trim wheel

the front gear steering wheel

 

That's it for the week end.

Thanks for wathcing.

 

Regards

Euge

[Trojan Thunder]

Nice to see some more stuff done Euge. I am luv'n the scratch building

[72linerlover]

Thank you Ray for your comment.

I've frist to say that your Cormorant came out very nice. I know the pain of red and yellow painting, and you did very well.

 

The week end was useful to prepare some more stuff to add something inside the fuselage.

I'm not going for a full interior; just what i'm afraid could be seen through the windows.

 

The cabin floor

 

Preparing rails for the seats

 

Test fit of the rails into the floor

 

Some canvas seats in test position.

 

Hope to get back to the build next Wednesday.

Thanks for watching.

Euge

 

[Trojan Thunder]

Looks good Euge, I saw a nice Caribou build on another site the other day in Brasilian Police markings as I recall, the builder also scratch built the interior.

[Dutch]

Euge,  Amazing work thus far!  I am impressed.  Please keep the project going!

[72linerlover]

Hallo everybody.

Thak you Ray and Dutch.

Not so much to be impressed of: I made just something inside so that the fuselage does not look empty.

Last wednesday and today I finished the canvas seats and prepared the nets to be put inside the windows.

Still have to think at how attach them, but I'll thik it over after glueing the trasparecies.

 

Floor painted and supports done.

 

Test fit of the seats.

 

Seats glued on.

 

Test fit into the fuselage.

 

Here is how they look like from ... inside.

 

And here what seems to be visible from outside with the interior in the dark. Well, I got the result, didn't I?

 

Regards

Euge

[phantom]

Very nice. I went basic on mine. Make sure you put in LOADS of nose weight. Thought I had enough. 

 

Nope, had to add more.

[72linerlover]

Thank you, Phantom, for your comment.

One of the tasks of today will be balancing. I normaly put the parts together with tape and put the aircraft on two sticks where the main gear legs have to go and find the amount of weight. The real problem will be where to put it.

 

edit: And mine has a shorter nose than your.

Regards

Euge

Edited November 11, 2017 by 72linerlover

[72linerlover]

Hi, everybody.

I feel as I have passed around Cape Horn since I found how much ballast is needed: 65gr.

You can see the lead in the front of the fuselage.

 

Some testing with cardboard to cut out the lead and fit in the nose.

 

Ballast in position

 

Balancing test with the ballast on place

 

Now the dihedral problem.

I made two woden spars with the correct angle to be glued inside the upper wing.

The parts, of course, don't match the angle.

 

Then I engraved along the outer wing joint, outside of the engine, always in the inner face.

This allowded me to bend the part.

 

 

 

Now on the underside i had to do the same on the external skin, where I thought to insert some plastic to bend the wing.

Surprisingly there was no need to add anything and the part bent by itself. (sorry no pics)

 

Test fit of the dihrdral with each wing glued

 

Ok, I'm quite happy at the moment.
I think I'm going to face the funny side of the build.

 

Thank you.

Regards

Euge

 

Edited November 19, 2017 by 72linerlover

[Trojan Thunder]

Wow, 65 grams! that seems like a lot of weight!

 

I was working on a kit the other week where the nose weight was suggested as 20 grams, after some testing I only had to add about 5 grams.

 

Nice job on the dihedral adjustment, what angle is it supposed to be Euge? Great pictures of the process BTW!

 

[72linerlover]

Hi, Ray. Thank you for your kind words.

I didn't want to be tedious with the ballast operation.

Well, things are as follows: 65 gr. are put in the position you see in the first pic, 55 millimeters ahead of the lift point (main gear legs)

This makes a momentum of 3575 gr.x mm. putting the lead under the cockpit I gain 20 mm of arm, so 3575/75 = 47,6 grams, so 50. And this is the definitive amount. A lot anyway, but the nose is very short.

 

Dihedral.

The angle is 15°. This is the angle that the inner face of the upper wing half has to perform outboard of the nacelle, as you can see in the last pic of the unassembled wing.

I had no specific evidence of the real dihedral and I eyeballed it from the images on the net.

 

Sorry if I made some confusion, but it's not easy to explain in english.

 

Bye

Euge

[Trojan Thunder]

No confusion Euge, it is great to watch this build and corrections going ahead.

 

I am taking notes for my RAAF Caribou build

[AX 365]

That's some mighty fine work.  Very nice.

[72linerlover]

Dear friends,

If someone is interested HERE there is the continuation of this build.

Best regards.

Euge

[Dutch]

Euge,  Thank you for sharing your build and techniques with us.  I also appreciate your weight and balance calculations.  They are very helpful.  I have never done it by your method, I just simply keep adding weight until it sits, then add a little more.  Usually my models are rather too heavy, then I have problems with the gear holding them up.  So I really appreciate your more scientific approach! Beautiful work so far!  Please keep going in the new thread! R/ Dutch