[youtube]https://youtu.be/KGFsAOUdX7A[/youtube]

The Greg's Airplanes videos are always a well researched treat to watch

The -H is an entirely different airplane. Different fuselage, different wing planform, different airfoil, and a different tail. It is like the difference between a Legacy Hornet and a Super Hornet. In that case, my understanding it, it was done so that they would not have to go through a selection process.

Amazingly the P-51 goes back to 1940 when the British ordered a prototype and it was constructed in about 120 days. Engineering had mostly already been done as NAA had been shopping the design to the US Army Air Corps who showed little interest. The airframe and wing changed little from 1940 through the P-51A (Allison V-1710 w/3 Blade Prop), B/C (Packard builr Rolls Royce V-1650 w/4 blade prop) and D/K (Bubble Canopy and inboard leading edge change as well as 2 more Machine Guns in the wings).
The H came from R&D work going back to 1943. This was a few different prototypes based on lightning the airframe and higher horsepower Merlin variants. P-51J, G and F.
In the late 1943 timeframe the USAAC decided Fighters needed more fuel. For the P-51B/C and D/K a fuselage Cell behind the Pilot was added for an additional 80 Gals. The Lightwweight P-51 Prototypes were all designed without this feature and some additional engineering was needed resulting in the P-51H. Closely related to the P-51J. The Packard Merlin V-1650-9 had Water Alcohol Injection and was rated to 2200 HP. The 1st Merlin's built by RR were barely 1000 HP. Quite a jump in about 8 years of use.

WWII Chart from Dec 1944 comparing late R-2800 P-47D, P-51H and the new XP-8A Jet. Both P-47D and P-51H equipped with Water Injection. P-51H at 70" MP is less than the 80-90" MP the engine was capable of.


This website offers many WWII Flight Testing Data for many of the Fighters used around the world.
This is the data from USAAF testing of a P-51H to corroborate NAA Data. Links to Scans of original charts at the bottom of the page.
http://www.wwiiaircraftperformance.org/ ... 64182.html

From NAA Report revised after A/C flew and tested.
At 70"+ of MP the engine is using more than 3 gal of fuel per minute.

Image from Aircorpslibrary.com-

Despite the performance differences, I think the D model (top) was a bit better looking.

Top photo A/C is still airworthy. Was sent to NACA and became NACA 127, one of a fleet of NACA P-51s configured for High Speed Research with shaped alum plates over the gun bays and a tall tail. Airflow over the top of the wing would exceed MACH 1 at .75-.8 Mach. Shapes and test articles would be bolted to the upper wing and dives from high altitudes would be performed. The DG would be rotated 90 degrees and zeroed while level. Dives at 25 degrees nose down could be performed. Camera’s and instrumentation where installed.
2 other NACA P-51s are also flying today.

I talked to the owner of the world's only flying H-model at an airshow this summer. They made lots of non-performance improvements as well. The cowling is different, providing much better engine access, and that line in the way when accessing the spark plugs is gone. They put a lip on the canopy to stop the air leaks, and put in a Janitrol heater to keep the cockpit warm. It's clear the designers talked to many pilots and crew chiefs, not just aerodynamicists.

Interesting that the charts show a "combat rating" higher than a "war emergency rating." Never heard of that before.

Wikipedia says there are about 11 H models left of the 150 airworthy Mustangs in the world.

Great stuff.

Question, could you build a full size Mustang today if you had an *big* budget? Why are there no new replicas made? Maybe the stampings are the hard part?

--paul

Navy: We need a stealthy 4+ Gen fighter, but we can't afford it.
McDD/Boeing: Hold my beer.
Without a doubt, the greatest hoodwink the Navy ever pulled on Congress.

Some kind of link to an original serial number provides value that a homebuilt lacks.
Several have tried setting up homebuilt type replica redo with no real success.
In 07 2 Mustangs landing after displays at OSH hit at touchdown resulting in the loss of Gerry Beck and his P-51A which was registered as a homebuilt. So 1 has been built and flown.
Big budget will get you a real one. Several outfits around the country can do that for you.
One such is Aircorps Aviation. They took an airframe left abandoned in New Guinea and built it back to new, winning Grand Champion Warbird at OSH. They have done the same with several P-51s.

Difference is the water injection.
You could run 67” MP WEP dry, no ADI, which other Mustang models did as well with the high octane fuel.
With ADI you could run 90” MP, combat power.

Mike Coutches son or grandson I presume?

Dan