Author Topic: McDonnell Douglas AV-19A  (Read 36280 times)

Offline kitnut617

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McDonnell Douglas AV-19A
« on: January 07, 2012, 03:52:59 AM »
I've got this going on at the moment, a Harrier Replacement  (not an alternative to the F-35 I might add)

« Last Edit: January 07, 2012, 03:55:51 AM by kitnut617 »

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Re: McDonnell Douglas AV-19A
« Reply #1 on: January 07, 2012, 03:58:46 AM »
Looking good!  Would love to see the rest of your WIP on this project. 
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Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #2 on: January 07, 2012, 04:05:59 AM »
I'll post it up soon Jeffry --

Offline finsrin

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Re: McDonnell Douglas AV-19A
« Reply #3 on: January 07, 2012, 10:21:03 AM »
Good flowing together of diferent models, looks legit.
See it as low end of high/low (cost) mix of new generation of STOVL fighters.  Force mix of this and F-35.

Offline John Howling Mouse

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Re: McDonnell Douglas AV-19A
« Reply #4 on: January 07, 2012, 11:51:33 AM »
And, knowing you, every technical aspect from the theoretical pitch-roll controls to the CoG are perfectly thought out!!  ;)
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Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #5 on: January 08, 2012, 12:14:58 AM »
And, knowing you, every technical aspect from the theoretical pitch-roll controls to the CoG are perfectly thought out!!  ;)

Weeeell !  -- I had given it a bit of thought    :icon_meditation:

Offline Brian da Basher

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Re: McDonnell Douglas AV-19A
« Reply #6 on: January 09, 2012, 07:06:33 AM »
Yowsa that's looking good, kitnut! You've got some serious design skills!

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Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #7 on: January 09, 2012, 07:41:14 AM »
Thanks BdB ---

for this project I took a bunch of parts from these below and jumbled them around a bit. I've got in 1/72, a F-15, F-18, a Tonka and AV-8B and in 1/100 another F-15. Also a fan front from a 1/144 767
« Last Edit: January 09, 2012, 07:44:20 AM by kitnut617 »

Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #8 on: January 11, 2012, 03:31:51 AM »
For the longest time I've been trying to come up with a plausable way to make a Harrier supersonic.  I've read all about the various methods that were design to accomplish this, from a PCB Pegasus modified Harrier, through the HS P.1154 to the BAe P.1214/1216 projects.  I've read somewhere that RR even proposed a much more powerful Pegasus with thrust output upped to between 30,000 and 35,000 lbs.  This invovled many refinements to the existing Pegasus and also an increase in the fan diameter of around 3-4 inches more than the standard Pegasus and keeping with the cold/hot nozzles idea.  It wasn't proceded with because the whole engine would have had to be bigger and the GR.5/AV-8B was already well underway at the time, and there just wasn't any room for this engine to fit in the fuselage.

Most of my thoughts had revolved around how to convert a Harrier to have ramp style air intakes but the biggest stumbling block was how to intergrate the swivelling nozzles.  One of my thoughts was to have two smaller engines with swivelling hot exhaust similar to the P.1216 and a rear fuselage like a Jaguar or Phantom but placing the cold nozzles always proved to be a problem.  That was until the F-35 came along which is an aircraft I really like (one of the few I think), the cold air louver system seemed to me a really clever way of duplicating what the swivelling nozzles do, the only thing that I don't like about the F-35 system is the horizontal fan, gearbox and driveshaft, too much dead weight being dragged around for 90% of any mission and all the space that could be used for other equipment.  Still I like the approach the F-35 has gone in but don't get me wrong, I still love the Harrier.

I'm not sure when I started to rethink how to make a supersonic Harrier but I began to realize it would have to be a totally different design.  And it would have to revolve around the engine which would have ramp style intakes (my favorite system).  An idea started to form in mind while I was working on another project where I'm planning on making an Avro Atlantic powered by turbofan engines with fan diameter about the same as a Harrier's and installing them into a Vulcan wing.  This involved some new ducts and engine bays with the bypass air exiting above and below the wing.  It dawned on me that a regular type of turbofan would be a way for my new Harrier and then after studying a number of videos of turbofans on airliners I suddenly thought of a way to use the bypass air for the cold air lifting source.  I had been watching how certain turbofan engines actuate their thrust reversers, one type has the whole rear end of the nacelle move backwards to expose a gap where the bypass air is redirected through.  I thought if the mechanism was used to direct air down some ducting instead of just blasting out the sides I could have a pretty good VSTOL engine.  I also decided almost right away the bypass air would go out two ducts and the hot exhaust would have just one nozzle.  The two cold air ducts would have gimballed louvers on the bottom of my new fuselage and that these same ducts could also control pitch, roll and yaw through the louvers and through a variable area control inside the ducts.  With that figured out it was on to deciding what to use for my model.
« Last Edit: January 11, 2012, 03:58:51 AM by kitnut617 »

Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #9 on: January 24, 2012, 02:10:57 AM »
A question to our more knowledgeable members here, is there a US made equivalent to the Rolls Royce Olympus 103 (of 20,000 lb thrust)

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Re: McDonnell Douglas AV-19A
« Reply #10 on: January 24, 2012, 02:20:53 AM »
I assume you are talking same era?
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Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #11 on: January 24, 2012, 02:32:02 AM »
Not necessarily Greg, but something along the same dimensions though.  The idea behind this project is that the engine still used the cold/hot nozzles of the Pegasus, but more powerful.  I'm thinking either the Olympus 301 (EDIT) was modified into a turbofan, with the fan almost 6" bigger in diameter than the Pegasus fan, or I use a US made engine along the same lines.  I'm thinking the hot exhaust puts out 20,000 lb and the cold air bypass another 25,000 lbs.

Here's a couple of pics of how the engine is, top pic is the difference between the Pegasus fan and the one in this project. Second pic is of the engine core with a row of static blades attached to the front.  Third and forth pic is how it goes inside the airframe. Of course I'm jumping ahead with the build here.
« Last Edit: January 24, 2012, 02:52:27 AM by kitnut617 »

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Re: McDonnell Douglas AV-19A
« Reply #12 on: January 24, 2012, 02:36:22 AM »
I will do a little research for you.
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Re: McDonnell Douglas AV-19A
« Reply #13 on: January 24, 2012, 02:52:27 AM »
The (Wikipedia) Pratt and Whitney F100 is close to what you are looking for in that performance class.  The F401 was a derivative of the F100 developed for the Rockwell XFV-12 prototype supersonic VTOL fighter
« Last Edit: January 24, 2012, 02:57:08 AM by Jeffry Fontaine »
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Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #14 on: January 24, 2012, 02:56:00 AM »
Thanks Jeffry, but I forgot to add something, 20,000 lb non-afterburning thrust.  This engine for the project doesn't have an afterburner  ---

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Re: McDonnell Douglas AV-19A
« Reply #15 on: January 24, 2012, 05:48:43 AM »
Would that be the J-67 ?  The one they proposed for the XF-103 Thunderwarrior?

Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #16 on: January 28, 2012, 09:40:34 AM »
Would that be the J-67 ?  The one they proposed for the XF-103 Thunderwarrior?

Doing a google on that it sounds about right I think dj   :)

Anyway I've modified my engine a bit, I needed to shorten the exhaust pipe and make the engine a bit longer after reading some other stuff on the internet about various engines.  Although the diameter is close to what I was looking for.

Top pic shows where I added a length in, and the second pic give a certain perspective on the lump.  Incidently, I've seen a photo of an actual Olympus production line which looks a lot like this.  IIRC, Jon posted it in my AV-19 thread on the 'other' forum.

Offline elmayerle

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Re: McDonnell Douglas AV-19A
« Reply #17 on: January 29, 2012, 08:53:09 AM »
The (Wikipedia) Pratt and Whitney F100 is close to what you are looking for in that performance class.  The F401 was a derivative of the F100 developed for the Rockwell XFV-12 prototype supersonic VTOL fighter.

Er, the F401 was a sibling of the F100, intended primarily for the F-14 and also used in the abortive XFV-12A which turned out to have significant duct loses when scaled up from test rigs.  Way back when I first got into aerospace, I worked for P&W's Florida operation on the F100 and F401.

Offline elmayerle

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Re: McDonnell Douglas AV-19A
« Reply #18 on: January 29, 2012, 08:56:43 AM »
For reference purposes, here's a frontal view of something St. Louis was playing with.

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Re: McDonnell Douglas AV-19A
« Reply #19 on: January 29, 2012, 11:15:04 AM »
Any more details?
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Offline elmayerle

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Re: McDonnell Douglas AV-19A
« Reply #20 on: January 29, 2012, 12:39:32 PM »
Any more details?
Unfortunately, no.  I wish like heck that I did but it does create lots of room for speculation.  I've another drawing from the same source which depicts a stretched Harrier II concept and there's enough information in Heart of the Harrier to make some good approximations for modelling purposes; that one is tempting to do as a CILOP program to keep the USMC's Harriers fully competitive a while longer and would also involve an engine upgrade.  It might be interesting to do along side a developed version of the subsonic AV-16 concept.

Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #21 on: January 30, 2012, 12:22:23 AM »
Here's a sketch of what my thinking is on this engine, it is a turbofan of 45,000 lb thrust, approx' 20,000 lb of hot exhaust the rest made up from bypassed air.  When transitioning into the hover, the bypass air flowing backwards is blocked off and diverted down the two side ducts to the bottom of the aircraft, while at the same time the hot exhaust nozzle swivels downwards too.

Second pic shows where the cold air duct exit on the bottom of the fuselage, just in front of the wheel bays.
« Last Edit: January 07, 2013, 04:46:43 AM by kitnut617 »

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Re: McDonnell Douglas AV-19A
« Reply #22 on: January 30, 2012, 01:02:04 AM »
That is freakin brilliant and beautiful :-*

Offline elmayerle

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Re: McDonnell Douglas AV-19A
« Reply #23 on: January 30, 2012, 02:11:39 AM »
Not too far off from some of the tandem fan concepts out there.  This is looking most interesting.

Offline kitnut617

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Re: McDonnell Douglas AV-19A
« Reply #24 on: January 30, 2012, 02:44:56 AM »
Thanks guys---

My idea is that the USMC approached McDonnell Douglas to see if they could enhance the AV-8B's (which they really like). They wanted it to be able to do more of what it does really well.  McD responded by saying that the Harrier as the Marine Corp knows it was at the end of it's development and to increase it's capability would mean a new airframe design.  McD came back with a design which used elements of all three of their important fighters, the F-15, the F-18 and the Harrier

I've read somewhere that Rolls Royce had proposed a more powerful Pegasus but it had an increased fan diameter (about 3 or 4 inches bigger than the standard Pegasus) and it was too late to incorporate into the new Harrier GR.5/AV-8B because it wouldn't fit inside the airframe so wasn't proceded with. It would have had somewhere between 30,000 and 35,000 lbs of thrust.

With that in mind, I decided that my project would have a bigger engine, the fan diameter works out to be 6" bigger in diameter, and I wanted to use the F-15 air intakes (my favorite intake system BTW).  I had worked out the area of the Harrier intake and the F-15 intakes and found that two F-15 intakes would work for the engine I'm thinking about, but slightly reduced in size.  So keeping with already proven designs, I thought a scaled down F-15 wing would work for this project, I found that a 1/100 scale F-15 wing was still bigger than a 1/72 AV-8B wing.  So that where the idea all developed from.

Here's another couple of pics of the project further into the build which shows the two wing sizes.  The AV-19 is a bit bigger than an AV-8B but almost the same size as a TAV-8B

I chose the designation AV-19A because while researching what I could call it, I found that McD had been reserved the number V-19 for a VTOL project.  I thought that was too much of a coincidence not to go with it.
« Last Edit: January 30, 2012, 08:42:22 AM by kitnut617 »