1:72 Italeri H-21 Flying Banana

[Sgt.Squarehead]

I'll start packing.....One lump or two (I've got a few of them)?

Edited December 6, 2013 by Sgt.Squarehead

[Nigel Heath]

I don't want to appear greedy but I think two will give me more options.

[Nigel Heath]

This is what the actual radial engine looks like:

I have established it was indeed used in Sherman tanks - perfect. Are those silver pipes fuel lines, armoured ignition wires or what?

Edited December 6, 2013 by Nigel Heath

[Moggy]

This is what the actual radial engine looks like:

I have established it was indeed used in Sherman tanks - perfect. Are those silver pipes fuel lines, armoured ignition wires or what?

It's the ignition harness I think

[Sgt.Squarehead]

They appear to be connected to the spark plugs!

Here's how the engine looks in a tank: http://qa.operatorchan.org/v/src/13300254015.jpg

Edited December 6, 2013 by Sgt.Squarehead

[Nigel Heath]

I worked it out in the car on the drive home that was all they could be, no way was this thing fuel injected - it was developed in the 1930's. This helicopter was one of its twilight applications. It makes sense really, you would not want unprotected cables flapping around in the air flow round these things. Looks like two plugs per cylinder as well.

Your link does not work for me KT - I get an error 404 message.

Edited December 6, 2013 by Nigel Heath

[Nigel Heath]

Banana Build - Day 13

I have printed off the cutaway drawing to provide a handy reference:

I also enlarged the engine area:

I think the engine is a stylised representation to make the artists life easier, I am pretty sure it would not be encased in sheet metal like that. It might get a bit hot...

I also printed this off so I can name all the parts correctly. Could that oil tank be called the "Oil Scupper"? Or is that just the filling point?

Note that the big holes at the rear have a door to stop birds nesting in there and such like.

Using this information I produced a drawing to clarify the location of everything:

The gearbox where the drive splits is in a fully enclosed compartment on my model so its details can be safely ignored. It looks like there is actually a lot of empty space in the engine compartment. I might just flesh it out twith a few random electrical boxes or something like that. My thinking is also to put some mesh on the floor of the compartment to hide the join and the main undercarriage plate.

Edited December 16, 2013 by Mike

[Bengalensis]

I have no clue what was the case of the H-21, but many air cooled engines are enclosed in sheet metal ducting, to direct the air flow from the internal driven cooling fan. Great to see cutaways and drawings of this bird, I'm a bit of a sucker for advanced transmission and drive systems. Great project, again.

[Jessica]

Having the engine ducted like that is quite common in helicopters. It allows for the forced-air cooling to flow over the cylinders no matter the airspeed. Here's an H-19 installation for comparison. You can likely sculpt the shape with Milliput.

[Sgt.Squarehead]

I have no clue what was the case of the H-21, but many air cooled engines are enclosed in sheet metal ducting, to direct the air flow from the internal driven cooling fan. Great to see cutaways and drawings of this bird, I'm a bit of a sucker for advanced transmission and drive systems. Great project, again.

This might interest you (and even be helpful for the build):

EDIT - Just noticed this one:

Edited December 6, 2013 by Sgt.Squarehead

[Nigel Heath]

I am thinking I should razor saw off the spurious engine detail off this part, now I am going to be getting super detailed radial engines courtesy of the very generous KT:

But I would rather wait until I had the parts in my hands. Even with the Christmast post, that should not be too long, given KT's incrediblly efficient postal system.

I was going to use 1.0mm brass rod for all the drive shafts but I can see that the main one coming directly from the engine is of a bigger diameter (makes complete engineering sense). Looking through my modelling materials storage system, I found this rod which is actually plastic coated steel rod with an OD of 1.2mm which equates to 86mm in real life - ideal I think. It will have to go through a new hole in the bulkhead here:

This is how it looks with the 1mm drive shaft in the right sort of area:

Edited December 6, 2013 by Nigel Heath

[Sgt.Squarehead]

I'd hold fire for a bit Nige.....I wouldn't say anything out of an ESCI tank kit could ever be described as 'super-detailed', but they might be useful in conjunction with the kit bits and some scratchwork.

[infofrog]

What a great job .....

[hendie]

Nigel, have you seen these?

http://www.primeportal.net/hangar/howard_mason2/h-21/index.php?Page=1

http://www.primeportal.net/hangar/howard_mason2/h-21_ahm/index.php?Page=1

http://www.bredow-web.de/Luftwaffenmuseum/Hubschrauber/Vertol_H-21/vertol_h-21.html

http://www.flugzeug-bild.de/name/einzelbild/number/29726/kategorie/Hubschrauber~Sikorsky~Sonstige.html

some really good quality photographs

[IGKent]

This might interest you (and even be helpful for the build):

Yes...! Very interesting clips! Especially, it take off as aircraft

[Pete in Lincs]

Nigel,

With a bit of crafty painting & bits of brass,

The cap from a detergent bottle (Or similar)

should do you for an engine. No one else will know.

(Except this lot. And who are they going to tell?)

This week I are bin mostly listening to Sherman Tanks

(Band of Brothers)

Pete

[IGKent]

I would like to see the finished radial engine...))

[IGKent]

Where is BANANA cockpit, Nigel? Are you gonna do it?

[Jessica]

My initial thinking on the ducting is to make something out of plasticard - early days yet. I also need a fan now - something like the one of the front of a Fw190 I suppose. Much to think about.

If you find one in the right size, a bottle like this, suitably trimmed, can work.

[Nigel Heath]

Today, 03:12 AM

Nigel, have you seen these?

No, I had not seen any of these - thanks hendie. (quote button now working).

Some very useful photos there, it felt a bit like I was looking right up her skirt in some (I liked that). Reference wise I think I have it pretty well covered now.

Edited December 7, 2013 by Nigel Heath

[Nigel Heath]

Where is BANANA cockpit, Nigel? Are you gonna do it?

Boring, conventional builds would start with the cockpit. Due to the non-arrival of my PE sets this one is going all over the place.

On the ducting for the engine, I had thought about using a plastic bottle of some sort. I will have a look through my recycling bins when the engines arrive. There is nothing suitable at the moment but I will keep the modelling radar switched on.

Edited December 7, 2013 by Nigel Heath

[Nigel Heath]

Banana Build - Day 13

You may have spotted that not a lot actually happened last night, today I will put that right. I started off by creating the hole for the main drive shaft which I think looks like this:

I thought the perforated brace looked too thick so I thinned it on some wet and dry:

I also finished drilling all the holes in it as it will now be fully exposed:

You may recall that last weekend I was trying to locate a pot of zinc chromate paint. Looking at all the references it appears that the engine bay is a yery yellow colour and decide that this tin I already had is just right:

The one with the red oxide finish appears to be an abberation.

Turning thoughts to the main undercarriage I established that the hole in the wheels was 1.2mm in diameter:

In a small subdivision of my modelling materials storage facility I find that all I have of the correct diameter is this piece of steel:

That won't do at all. I do have a few pieces at 1.5mm diameter, I might have to drill out to that size.

Some of you that follow these things may recall that I am a finalist in a little cookery competition at work. Well, the finals will take place on Tuesday. I have a cunning plan to crush the opposition which involves doing some shopping this afternoon. I also want to fit "Gravity" into my busy schedule.

So its bye for now,

Nigel

Edited December 16, 2013 by Mike

[Nigel Heath]

Nahh, I looked at that, its steel. They did brass wire for jewellery making but it was too fine. At times like this I really miss Model Zone.

I cut a piece out of this mesh for the floor grating:

It will go here:

These redundant parts can now be consigned to the spares box:

Edited December 16, 2013 by Mike

[Nigel Heath]

Still seeking out things to do, this front undercariage strut is a good candidate for replacement with brass rods:

The thickness varied widely between 0.65 and 0.94mm, 0.8mm might be a good compromise:

Tomorrow I have volunteered to help clear out the terminally ill John's library. I also have to make the recipes for my cookery competition so Banana Building may be somewhat limited. Please forgive me.

Bye for now,

Nigel

[Nigel Heath]

Banana Build - Day 14

Most of today has been spent in the kitchen and shifting John's library but I have just got some done.

I first thought those round things on the side of the front strut were ejector pips and was about to cut them off but realized in time they were landing lights. My machine does not have them currently but I think I might keep them, spammed up with clear lenses they could look good. The instructions also state that the projection between them should be removed on my version but I like the little feller and will keep it:

I then thought that the carpet monster had eaten the diagonal brace and went on a hunt for it. I did not find it but did find the long lost replacement Rotodyne front undercarriage door:

Bizzare.

I then found it here:

Italieri don't provide holes or slots for the brace they just sit on the surface like this:

Poor effort really, on the real machines the struts smoothly transition into the fuselage. I drilled out some appropriate diagonal holes:

On the references I can see there is actually a little fishplate at the apex of the struts. I went for a search in the PE spares box and retrieved this almost ready made piece:

Bent and trimmed like this:

Prepped for soldering alongside the feeble kit part:

And done:

Here it is roughly installed:

I might get some more done later, we shall see. First bath and dinnner.

Edited December 8, 2013 by Nigel Heath