Author Topic: McDonnell Douglas AV-19A  (Read 22948 times)

Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #75 on: January 29, 2013, 06:18:29 AM »
Thanks BdaB, my son was watching me do this over the weekend and he said to me, ' this would be neat if you were building it in 1/24 scale and make everything work as you think it should'. 

Got me thinking that ---  1/32 maybe -----

Offline ChrisF

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Re: McDonnell Douglas AV-19A
« Reply #76 on: January 29, 2013, 08:06:51 AM »
Ya better finish this one first !

Maybe call it practice ? ;)  lol

Offline elmayerle

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Re: McDonnell Douglas AV-19A
« Reply #77 on: January 29, 2013, 09:31:00 AM »
And this is how it looks now that the ducts are glued in to the model, I've painted around them so I can see what needs tidying up.
Very nice and quite elegant.  Do the cold flow ducts have variable vanes at their exits to give a limited amount of vectoring?  I'm thinking back to the cold exhaust nozzle vanes on the F-35B.

Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #78 on: January 29, 2013, 10:31:21 AM »
And this is how it looks now that the ducts are glued in to the model, I've painted around them so I can see what needs tidying up.
Very nice and quite elegant.  Do the cold flow ducts have variable vanes at their exits to give a limited amount of vectoring?  I'm thinking back to the cold exhaust nozzle vanes on the F-35B.

Thanks Evan, and yes that is what I'm thinking of, there will be about five of them on each duct. The idea is they will be able to rotate so they point five or ten degrees forward so that when in the hover the aircraft could move backwards (like a Harrier) and then they will rotate totally backwards until they close off completely and shut the duct off for forward flight.  And because the vanes are mounted on a hinged frame where the hinge centers are orientated for/aft, there's a certain amount of rocking that can direct the air stream to the sides, which will work in hand with the yaw control of the hot air nozzle. 

The idea is that all the controls for hovering go through these ducts and the hot exhaust nozzle instead of having 'puffers' like the Harrier has.  I had thought that something like an area control actuator in the duct that would vary the pressure in each duct for roll control, but I've had another thought.  I think what it needs is an actuator controlled vent on the top side of the fuselage and when the aircraft goes into the hover, these vents would be partially open so air would be always exiting upwards but only when in the hover.  For the roll control, these vents would either open or close opposite to each other, then for pitch up these vents would close off, and for pitch down they would fully open.  By doing this the vents would raise or lower the pressure in each duct and of course be infinitely variable.

Once all the PSR is finished and I get all the u/c on, I'll add these vanes to the ducts.
« Last Edit: January 29, 2013, 10:35:51 AM by kitnut617 »

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Re: McDonnell Douglas AV-19A
« Reply #79 on: February 02, 2013, 03:21:05 AM »
Ya better finish this one first !

Maybe call it practice ? ;)  lol

A scale model of his scale model... ;D
All hail the God of Frustration!!!

You can't outrun Death forever.
But you can make the Bastard work for it.

Offline ChrisF

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Re: McDonnell Douglas AV-19A
« Reply #80 on: February 02, 2013, 08:25:56 AM »
Ya better finish this one first !

Maybe call it practice ? ;)  lol

A scale model of his scale model... ;D

Dont pretend you havent at least thought of it yourself ;)

Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #81 on: February 11, 2013, 01:11:20 AM »
Got a bit more done, I've worked on the exhaust nozzle now.  I've made two, one as in forward flight and one for in the hover.  I've made them so they're a friction fit into the rear end of the engine, this way I can display the model two ways although the doors will always be in the down position.


Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #82 on: February 11, 2013, 01:15:09 AM »
I wanted them to have an appearance of having stiffeners on the outside of the pipe so I drew up some shapes which I then printed on sticky-back paper, then stuck to styrene (top pic).

I then cut them out leaving one staying all attached (2nd pic) and the other I split into sections (3rd pic)

Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #83 on: February 11, 2013, 01:21:16 AM »
For the straight through pipe I just glued the joined shape to some brass tubing but I used some aluminum tubing with thicker wall for the turned down pipe.  This was so there was more contact area for super glueing at the joints.  I forgot to take some pics of the straight pipe during fabrication, but it was similar to how I did the turned-down pipe. Top pic shows the two together but with no stiffeners on the turned-down one.  2nd pic is just a scale comparison with a quarter (about the size a 5P coin for our friends on the other side).  3rd pic is of the stiffeners glued on

Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #84 on: February 11, 2013, 01:24:21 AM »
Here's how it looks in the model, top pic is of the straight pipe attached to the engine, you can see I've cut the doors off the rear fuselage.

The others are with the turned-down pipe in place.

Offline Brian da Basher

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Re: McDonnell Douglas AV-19A
« Reply #85 on: February 11, 2013, 02:57:10 AM »
Those are some amazing details, kitnut! By the time you're done, you'll have everyone believing your AV-19A was real!

Brian da Basher

Offline taiidantomcat

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Re: McDonnell Douglas AV-19A
« Reply #86 on: February 11, 2013, 04:10:03 AM »
Holy cow! excellent craftsmanship!
"They know you can do anything, So the question is, what don't you do?"

-David Fincher

Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #87 on: February 11, 2013, 08:12:21 AM »
Thanks guys, the photos are really showing up the flaws though, it doesn't look as rough when I'm looking at the parts ----hmm!!

Offline elmayerle

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Re: McDonnell Douglas AV-19A
« Reply #88 on: February 11, 2013, 10:21:15 AM »
Still looking good so far.  I suspect the photos provide you with enough distance that you can see what needs tweaking, but I certainly don't see anything wrong.

Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #89 on: February 11, 2013, 11:34:09 PM »
Thanks Evan ---

Just a technical note,  I used round tube because in this scale it's easier to use (and get by with) but in the real world, the sections of pipe are not actually round, at least that's how they develop out as when I draw it correctly.  The reason is the angled connections are actually round because there's a bearing race there which means the short straight section parts are a round to angled round tranistion, and the middle straight section  is really an elipse in shape

This below might help with the explanation.  If you cut a round pipe at an angle, the resulting cut face is an elipse, in reverse, if the angle cut is actually round then the piece of pipe is really eliptical in shape

Offline Eddie M.

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Re: McDonnell Douglas AV-19A
« Reply #90 on: February 12, 2013, 07:51:49 AM »
Absolutely stunning work. Nice to see your work again. :)
He really DID lose his marbles!

Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #91 on: February 13, 2013, 07:27:18 AM »
Hey Eddie, where've you been --- thanks for your kind words   :-[

Offline Eddie M.

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Re: McDonnell Douglas AV-19A
« Reply #92 on: February 15, 2013, 05:45:11 AM »
Wondering aimlessly through the void looking for my mojo. Haven't completed a model in over a year, but still chipping away at many. Got a whif Super Hornet that's so close to being done I can taste it. But, as in a bad dream, I just can get there. Maybe I should hang out here more.  ;)
He really DID lose his marbles!

Offline kitnut617

  • Measures the actual aircraft before modelling it...we have the photographic evidence.
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Re: McDonnell Douglas AV-19A
« Reply #93 on: February 15, 2013, 06:16:44 AM »
Wondering aimlessly through the void looking for my mojo. Haven't completed a model in over a year, but still chipping away at many.

I know where you're coming from, only manage to do one in over 18 months I think (Supermarine Seafire (Hybrid) Mk.45) but that got me back onto this one.  I'm going to make a big effort to finish a few that are mostly done but got shelved because I moved on to something else.

Maybe I should hang out here more.  ;)

See, there's the answer ---  ;)

Offline Eddie M.

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Re: McDonnell Douglas AV-19A
« Reply #94 on: February 15, 2013, 06:36:03 AM »
I must admit, a certain social website was occupying a lot of my time and I decided to deactivate that so that I might actually get back to having a life and hobby.  ;)

Now, if I could just find the cowling to the bird I'm working on. A new cat in the house and he's trying to derail my comeback. ;D
He really DID lose his marbles!

Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #95 on: February 18, 2013, 05:05:18 AM »
Nothing much in progress at the moment, got a bit busy.  But I did glue the tail surfaces on and sorted out the canopy.   If anyone has built an Airfix Harrier GR.5/7 they would know that the canopy is just way too wide for where it's supposed to go.  I thought I had figured out what to do, I carefully squeezed it in and glued a small strip of styrene to the bottom edge to hold it in shape. I then glued the windshield on, leaving it overnight to make sure it cured properly.  Next day I saw all these little stress fractures had appeared all over the top of the canopy so I thought I would stress relieve it.  I put it in a cup of water and then zapped it in the microwave, weelll -- it didn't go to plan  --- it shrunk into a little blob of plastic --  so that was the end of that.

I'm now on my last canopy set from an Airfix GR.5/7 kit and what with some that were broken already and others which ended up broken, all from trying to get it to fit onto a fuselage, I've now got four of them which have no canopy ---  and there's no aftermarket product to get --  :-X :-X  Looks like I'll have to try and do one myself --

Offline GTX_Admin

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Re: McDonnell Douglas AV-19A
« Reply #96 on: February 18, 2013, 05:18:32 AM »
Nothing from a vacuformed pov?
All hail the God of Frustration!!!

You can't outrun Death forever.
But you can make the Bastard work for it.

Offline kitnut617

  • Measures the actual aircraft before modelling it...we have the photographic evidence.
  • I'd rather be dirtbike riding
Re: McDonnell Douglas AV-19A
« Reply #97 on: February 18, 2013, 05:28:45 AM »
Nothing from a vacuformed pov?

No there isn't anything out there and considering the problems with the canopy from this kit I find that surprising as every one of the Airfix GR.5/7 are like this that I've come across, and even the T-10 kit has the canopy sections too wide too.  I don't know if it a situation where over time the canopy sort of stress relieves itself and goes out of shape, but when I pulled the blob of plastic out of the hot water I was somewhat surprised by the result.

My last canopy I've got comes from the Airfix Club kit, Sea Harrier and GR.7.  I carefully squeezed this one to fit the windshield part and just glued the windshield on it, and stress fractures are already appearing on the canopy part.  Really odd ---
« Last Edit: February 18, 2013, 05:34:15 AM by kitnut617 »

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Re: McDonnell Douglas AV-19A
« Reply #98 on: February 18, 2013, 05:39:04 AM »
Would it be better to use the existing canopy as a modl to make some Vacuform/smash form canopies?
All hail the God of Frustration!!!

You can't outrun Death forever.
But you can make the Bastard work for it.

Offline kitnut617

  • Measures the actual aircraft before modelling it...we have the photographic evidence.
  • I'd rather be dirtbike riding
Re: McDonnell Douglas AV-19A
« Reply #99 on: February 18, 2013, 05:41:49 AM »
Would it be better to use the existing canopy as a modl to make some Vacuform/smash form canopies?

I think that's what I'm going to do Greg, only I've got to buy another Airfix GR.7.  Maybe I'll get the new GR.9 kit and see what I can do with that. I think though, I'll make a resin mould and vacuform it correctly, I've been studying the moulds I have for the Victoria Products 1/72 Avro Arrow and that's what they did there.