F3H-2 Demon 1:48 Build diary

[hyair]

The F3H-1 is the story of the Demon and the J40. Many naval fighters were supposed to use the J40 including the Skyray , Skywarriour but here Douglas was smarter then Macdonnell as we will see later.
The Demon was planned as a fast intrceptor for the US navy . The fuselage was 18 meter long
and the engine J40 with AB was designed to give it supersonic speed in level flight. As
with the Skyray first the Demon flew with the non AB engine than with AB version. The Demon
was bigger and heavier than the skyray so the fighter was even more underpowered if we compare it to the Skyray. Because of the Korea war the navy gave permission to Macdonell
to start produce it even before all the tests were done - a fatal mistake !!!
The J40 was intended to give the Demon top performance but proved very problematic !
During a short period of time after very serious string of accidents which the J40 was the main cause the navy decided to ground all the F3H-1and not to put them into service.
By the time the decision was made more than 50 dash 1 were produced. In an
unpresidented act it was decided to send these 50 dash 1 Demons to be used as a ground
instructional trainers in different naval air bases. This was a majore blow to the program but the Demon was saved as we will se later thanks to the hard work of Macdonnell engineers !!!
Will be continued.

Yair

[cMags]

Looking good, Yair! Take care when working with the lower cowling. If you decide to cut out the gun ports and fabricate tubes, you'll need to cut back the formers/frame to allow clearance. Otherwise you'll need to color the ports in.

[hyair]

Thanks cMags - I will put black tubes for the 20 mm guns so it will look more realistic.
During the service life of the demon two guns were removed
in order to save weight as the Demon was still under powered with the Alison AB engine.

Thanks -Yair

[hyair]

I attach here photos of the Demon in 1:72 scale of Emhar of some
17 years ago.
The two auxilary fuel tanks below the fuselage were not carried very often because of the big
drag they created ! As it sound strnage the range was better with 1 fuel tank as this configuration had a much less drag.

Yair

[hyair]

The F3H-2 was designed to be a super sonic fighter which means crossing the sound barrier
in a level flight and not in a dive like the F-86 sabre for instanse.
Even with the Alison J72 engine the Demon could only pass the. Sound barrier in a steep dive
of around 35000 feet. So why a plane that has 45degrees span , an after burner that give 14300 thrust or 10000 without couldn't go supersonic in level flight ?
The answer can be described in two words - " bad aerodynamics ".if we look at the fuselage of the Demon it is very straight desegn. The wings are 45 degrees swept but were very big and
with thick week cord , the drag of the plane was very high- It could do 0.94 mach in a straight
level flight. When in after burner a boost of 4000 lb was not enough to be supeoppr sonic.
The Skyray with the J57 and 5000 lb boost barely made mach 1.05 in level flight.
The French super mystere had the Atar 101G engine with only 7400 lb military and 10200 lb
in after burner and had 1.2 mach in level flight.
This is because the better aerodynamics of the Super Mystere with very thin wings and a slick
fuselage.
In the next chapter I will explain the whitecomb erea rule .

Yair

[paperengineer]

Imagine an area ruled demon! That might even make it surpass the sabre!

[John Bowden]

Well they (McDonnell) did mock up a twin engines Demon and that really shows the Phantom lineage very nicely.............just picture a single seat Phantom with unbent wings and stabs..........

[hyair]

The story of the YF-102 is the story of the area rule. The YF-102 was intended to be a
supersonic fighter armed with 6 falcon missiles and 2.75 rockets in the missile compartment
doors. The test flights however were disappointing as it failed to achieve supersonic speed and couldn't pass mach 0.98 in a level flight. Two prototypes and one of them was destroyed
in an accident failed to go supersonic. The Convair company was at deep trouble. The help
came from Dr. Whitecomb that formulated in NASA labs the Area Rule in 1953. In an ordinary
planes the fuselage had straight lines running from front to rear and the wings area was
problematic as it raised the cross section area and the drag as well. The area rule dictate that
if at area of the wings we will narrow the fuselage in a shape of a coke bottle it will lower the
drag and will improve the aerodynamics .
Convair engineers had nothing to loose. They were in a hury to build the new YF-102A. The new design had a coke bottle shape and tips were added in the rear part along with 12 feet
that were added to the length of the fuselage.
In late 1954 the YF-102A went supersonic in the first flight and this paved the way toward
a big scale production of 1000 F-102 A that were built.
Now if we look at the Demon straight fuselage lines and the big thick wings we will understand very fast that it will be unable to go supersonic in level flight.
Had it had the area role implemented and the wings thickness reduced it could achieve
a speed of mach 1.2 at least in a level flight.
The Grumman F-11F Tiger was the first aircraft to be designed from the outset with the area rule but the J65 engine with AB was not strong enough to go behond 1.2 mach. The super Tiger with early J79 of 15000 lb reached mach 2.04 with essentially the same aerodynamics !

Yair

[hyair]

After a break of one week and completing the Cutlass for the annual competition it's time to continue with the Demon. The bulge lower part white places were filled with 4 rods of 20 mm guns that slightly emerge outside. The next step is the intakes. As always I put a coin as a ballast in the front.

Yair

[hyair]

The Demon was getting into service with delay because of the changes that were needed to adapt it to new alison J71engine. The J71 proved a mixture bag in service. There was an incident were a couple of Demons run into a storm and the engines flamed out during flight which is highly undesirable behavior. Also the Demon required heavy maintenance both
for the mechanics and electronics technicians. Two of the 4 20mm guns were removed in
order to make it lighter in flight. Even with this engine that gave somec14300 lb in AB the
Demon was under powered and the only way to go supersonic was a steep dive from 35000 feet. The engine was gas gusler and consumed a lot of fuel. From the 500 produced about
30 percent or 160 crashed in all kind of accidents !
It is a well known fact that the service of a Jet fighter on the carriers deck is much costlier
in terms of pilots lives and planes and the Demon was not an exeption bere.
Also the Demon bad short legs in terms of operational flight range.
So we can ask what was good about this plane if there are so many drawbacks in it.
Well it was the only plane at the time with a big radar that allowed it to fly at nights were
other planes stayed on the deck . It was the first plane to carry the second generation
Sparrow air to air missiles and was a stable platform when landing on a carrier.
Not many know that the F3H was the father of the Phantom F4H which was the name of the
first prototypes of the Phantom. When the Demon was parking nearby a phantom it was the same length but the cockpit was one meter higher !!! so like the Cutlass a very long ladder
was required to get into.

Will continue .
Yair