avatar_Scotaidh

F7U-3 Cutlass conversion

Started by Scotaidh, April 07, 2018, 08:54:44 AM

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Scotaidh

One of my projects for this year is to up-rate the engines in a Cutlass.  The engines I want are the J79s from an F-4 Phantom.  Looking at it, I realized that there are two ways to do this.

One is to just implant the engines and adjust the Cutlass' fuselage.  I did some math. <ugh>  The Cutlass' original engines, J-34s, were/are 112 inches long by 27 inches in diameter.  In 1/72 scale, that's about 1.5 inches long by 0.33 inches in diameter. 
The J-79 is 208.8 inches long by 38.4 inches in diameter - which is about 3 inches long by 1/2 inch in diameter.  This will require some shoe-hornery to fit - or a lot of PSR.
Ideally, it would look something like this:


The other option is to co-opt the F-4's complete wing & engine section, with the Cutlass cockpit and stabilizers attached.  Ideally again, that would look a bit like this:
Thistle dew, Pig - thistle dew!

Where am I going?  And why am I in a handbasket?

It's dark in the dark when it's dark. Ancient Ogre Proverb

"All right, boyz - the plan iz 'Win.'  And if ya lose, it's yer own fault 'coz ya didn't follow the plan."

Scotaidh

Thanks, O Salty One.  :)


Work to date.  I'm using yard-sale sign plastic as an underpinning for the fuselage centre stips.  It will also be used to increase the area of the vertical stabilizers, as I think the added thrust will require some taming.  Also, IIRC, the aircraft suffered from stability problems, as well as lack of power.

The items in the yellow box are the J-79 exhaust nozzles - you can see how over-size they appear next to the Cutlass.

I'm looking through the SSR for a replacement canopy - something a little more ... couth, I guess - one that actually lets the pilot see behind him. 
Thistle dew, Pig - thistle dew!

Where am I going?  And why am I in a handbasket?

It's dark in the dark when it's dark. Ancient Ogre Proverb

"All right, boyz - the plan iz 'Win.'  And if ya lose, it's yer own fault 'coz ya didn't follow the plan."

The Rat

One of the changes I've often toyed with, other than changing the engines of course, is extending the forward fuselage a bit and adding canards.
"My mind is a raging torrent, flooded with rivulets of thought, cascading into a waterfall of creative alternatives." Hedley Lamarr, Blazing Saddles

Life is too short to worry about perfection

Youtube: https://tinyurl.com/46dpfdpr

ysi_maniac

Will die without understanding this world.

The Rat

Just went to my notes. The engine I was planning on was a license built RR Avon, length: 126 in., diameter: 35.7 in., with almost 3x thrust.
"My mind is a raging torrent, flooded with rivulets of thought, cascading into a waterfall of creative alternatives." Hedley Lamarr, Blazing Saddles

Life is too short to worry about perfection

Youtube: https://tinyurl.com/46dpfdpr

JayBee

This may or may not help, but it appeared in a number of US magazines some years ago.

Ladies, Gentlemen, and Whiffers, I present the F-7D Cutlass.


Alle kunst ist umsunst wenn ein engel auf das zundloch brunzt!!

Sic biscuitus disintegratum!

Cats are not real. 
They are just physical manifestations of collisions between enigma & conundrum particles.

Any aircraft can be improved by giving it a SHARKMOUTH!

Scotaidh

Quote from: The Rat on April 07, 2018, 12:18:09 PM
Just went to my notes. The engine I was planning on was a license built RR Avon, length: 126 in., diameter: 35.7 in., with almost 3x thrust.

I've got one in mind for the RAF, using an F-4K with its RR Speys.  I'm looking for some 1/2" outside diameter tubing to mock up the engines to get the width right - I think I'll hit the hardware store tomorrow.
Thistle dew, Pig - thistle dew!

Where am I going?  And why am I in a handbasket?

It's dark in the dark when it's dark. Ancient Ogre Proverb

"All right, boyz - the plan iz 'Win.'  And if ya lose, it's yer own fault 'coz ya didn't follow the plan."

Scotaidh

Quote from: JayBee on April 07, 2018, 01:20:57 PM
This may or may not help, but it appeared in a number of US magazines some years ago.

Ladies, Gentlemen, and Whiffers, I present the F-7D Cutlass.




Is that a Tomcat nose?
Thistle dew, Pig - thistle dew!

Where am I going?  And why am I in a handbasket?

It's dark in the dark when it's dark. Ancient Ogre Proverb

"All right, boyz - the plan iz 'Win.'  And if ya lose, it's yer own fault 'coz ya didn't follow the plan."

rickshaw

Quote from: Scotaidh on April 08, 2018, 03:58:30 AM
Quote from: JayBee on April 07, 2018, 01:20:57 PM
This may or may not help, but it appeared in a number of US magazines some years ago.

Ladies, Gentlemen, and Whiffers, I present the F-7D Cutlass.




Is that a Tomcat nose?

Nope, too short.  I'd suggest it might be a Tomcat canopy though...
How to reduce carbon emissions - Tip #1 - Walk to the Bar for drinks.

Scotaidh


F7U-3 Cutlass - 004 I found some half-inch diameter tubular objects that could be made the correct length - party favour penny whistles. Not really the right sort of plastic, but as George Carlin once said, you can't have everything - where would you put it? ;-) Because the whistles are made of food-grade plastic, normal model glues just won't stick, so a mechanical joint was necessary to join the turkey feathers to the body of the engine. The inside rear end of the whistle needed to be enlarged to accept the square tubing - I could have used a drill, but the ream is quieter and slower - gives me more time to make mistakes ;-) - I mean, more control. The kit intakes were originally one piece, so needed to be cut to allow widening. The kit's 'intake fans' are too small, of course. I may drill them out or make new ones - that decision is pending.


F7U-3 Cutlass - 005 The new engines are 3" long minus the turkey feathers. You can see better, in this picture, how too-small the original intake fans are.
Thistle dew, Pig - thistle dew!

Where am I going?  And why am I in a handbasket?

It's dark in the dark when it's dark. Ancient Ogre Proverb

"All right, boyz - the plan iz 'Win.'  And if ya lose, it's yer own fault 'coz ya didn't follow the plan."

albeback

#10
Love the idea. Just one small point though. The J-79 produced about 4 times the thrust of the J-34 engine!! A Cutlass so engined would be massively over powered would it not? How about a SINGLE J-79? Alternatively, the F-7/F-4 hybrid illustrated would seem to fit the bill just nicely!


Allan
Loves JMNs but could never eat a whole one!!

zenrat

Quote from: albeback on April 22, 2018, 03:35:58 AM
Love the idea. Just one small point though. The J-79 produced about 4 times the thrust of the J-34 engine!! A Cutlass so engined would be massively over powered would it not? How about a SINGLE J-79? Alternatively, the F-7/F-4 hybrid illustrated would seem to fit the bill just nicely!


Allan

You say that like massively overpowered is a bad thing... :unsure:
Fred

- Can't be bothered to do the proper research and get it right.

Another ill conceived, lazily thought out, crudely executed and badly painted piece of half arsed what-if modelling muppetry from zenrat industries.

zenrat industries:  We're everywhere...for your convenience..

albeback

 ;D Not a bit!! I like the idea!  In what if world, ANYTHING is possible!

Allan
Loves JMNs but could never eat a whole one!!

Scotaidh

Quote from: albeback on April 22, 2018, 03:35:58 AM
Love the idea. Just one small point though. The J-79 produced about 4 times the thrust of the J-34 engine!! A Cutlass so engined would be massively over powered would it not? How about a SINGLE J-79? Alternatively, the F-7/F-4 hybrid illustrated would seem to fit the bill just nicely!


Allan

I think overpowered is a good thing.  I mean, everyone knows that the English Electric Lightning was overpowered, and everyone loved it - the punters at the air shows who got to see it demonstrated, and the pilots who got to fly it. (Loved the power, I mean - no-one particularly liked its short range.)

So I think the Cutlass will be fine - we're going to reinforce the fuselage with Unobtainium, you know, and if that can make it to the centre of the Earth, as Hollywood assures us it can, then I think we'll be OK.  :)
Thistle dew, Pig - thistle dew!

Where am I going?  And why am I in a handbasket?

It's dark in the dark when it's dark. Ancient Ogre Proverb

"All right, boyz - the plan iz 'Win.'  And if ya lose, it's yer own fault 'coz ya didn't follow the plan."

Captain Canada

Great idea ! That I really going to look good. Now I want to build one myself lol
CANADA KICKS arse !!!!

Long Live the Commonwealth !!!
Vive les Canadiens !
Where's my beer ?