There is another flyable H but its been in hiding for a number of years now. Wonder when it'll come out of hiding with the aging of the only Whittington Brother left.

Just saw the H fly yesterday at the Reno Air Races. Came in last in its heat though.

Qualified 11th out of 21 Unlimiteds at 334.687, middle of the pack.
Thursday Heat 1A had 5 racers for 6 laps and the H finished 3rd at 332.702. Pretty consistent time with the Qualifying Speed.

There are owners who fly their stock airplanes without pushing them hard.

There are owners who push their stock airplanes hard.

There are owners who modify their airplanes and fly them hard.

There are owners who modify their airplanes a lot and fly them extremely hard.

I'd say the H is in the first category. Most owners are moving that way because the airplanes are so valuable and the cost of blowing an engine is 5x what it was 20 years ago.

The cooling system changes were also a very significant survivability improvement.

In the late 1960’s thru 1970’s Bill Hogan owned what he claimed was the only airworthy H-model, N313H. After Joe Hogan (brother) did my CPL check-ride, I asked for a walk around and he introduced me to Bill who indulged me. He mentioned that he was recently violated/suspended for doing aerobatics in an airway. Apparently the GADO did not buy Bill’s explanation that he was simply transiting the airway, inverted.

FWIW; the four brothers owned the Hamilton, Ohio airport. Painted on the side of their primary hangar in huge letters that could not be missed, “Hogan Bros. Private Airport.”

Understandable. Although they look similar, the D and H have no parts in common, and the owner told me there are no H parts available. They have to custom make everything. They also no longer use the ADI due to corrosion issues with the methanol/water mix, so they're running very conservative power settings.

The H uses a few parts borrowed from other NAA models, as do most of their piston designs. In 1941 the T-6 used the Model 73 Rudder Pedals with the NAA emblem cast into them. The Prototype Mustang was NA73X that flew in 1940. Bushings and mechanical design of the Rudder Pedals go back to the Prototype XO-47 Observation A/C in 1937 which is a Model 19. The H even has a couple 19-XXXXX part numbers listed in the Numerical Parts Listing section of the Parts Manual. Has some 62- and 82- parts borrowed from the B-25.
A couple pages from the P-51H Parts Manual. The 1st number of a NAA Part Number is the Model of the Type of A/C the part was designed for. It then will have a dash and 5 or more digits and possible another - and number, sometimes to denote which side if the part has a left and right fitment.
So this page shows a variety of 73- numbers used on the H. These go back to the 1st Allision powered P-51 Model.


On this page you see a variety of 117- numbers. The H started as the model 117, further design efforts ensued and it ended up in production as the Model 126.
Also on this page you see some 102 and 104 number. This is the P-51B and C models. 106 and 109 numbers go to the P-51D and K.


An example of a specific part is the 82-43289 Clip designed for the B-25. It ended up being used on all Merlin powered P-51s, including the 117 H. Usage listing is noted on the lower L/H block of the drawing.


There were a few 117 parts that were used on late P-51D production.
So while the vast majority of parts used on the H were new design, a number of parts came from earlier P-51 designs as well as other NAA designs. You don’t always have to reinvent the wheel.

Rich,

I have noticed a few taller (H-model?) vertical stabs on D-models. Was this a factory change, or more recent owner/field mod?

Doug,

Google 'Cavalier Mustang'. Could also be a TF-51 conversion (dual-cockpit).

P-51 morphed from a fighter, it was designed with the Allison V-12 which was altitude limited, to a high altitude fighter when the engine was changed to the Merlin. With the higher altitudes dives reached high airspeeds. At very high speeds it had less stability than was desired. The small triangular fillet in front of the vertical was developed and fitted to both B/C and D/Ks.
NAA and NACA continued R&D and developed the taller tail during WWII. NACA fitted it to the fleet of P-51s it used but the 1st P-51 I’ve seen it fitted to was a NAA P-51B used by NAA. The NACA 127 P-51D photo I posted featured the tall tail. They would dive to .8+ Mach.
In the mid/late 1950s the US disposed of most of the P-51s by a couple auctions and sales to foreign governments. A couple of the tall tail NACA birds ended up in civilian hands. One of those 2 ended up at Trans Florida, a small company that maintained P-51s. They later changed to Cavilier Aircraft. They copied the tall tall and it was a feature they could up sell to clients.
Today many dual control TF-51s have the tall tail. None of the TFs modified back in the later 1940s for the USAF had a tall tail.
The P-51H originally had a shorter tall like the P-51D. They had lengthened the fuselage a little but found it too needed a little more stability. The vertical was redesigned and made taller and quickly incorporated in the production line. The taller tails retrofitted to the ones produced with the short tail. Only 555 H models were produced at Inglewood before the war ended.

This is NACA 108 which Caviler purchased in 1958. It had the tall tail fitted at NACA. This is the oldest P-51D around. It was the 4th P-51D-5 off the assembly line at Inglewood and was kept by NAA and then ended up at NACA.
Cavalier put their modified wing on it and it was used as the Demonstrator for the Mk II Mustang. Today it is owned by the Lindsey Family who owned Cavalier.
This is the tall tail they copied and put on many P-51D and TF-51Ds.


Cal Pacific Airmotive owns the LTC-11 Limited Type Certificate for the 3 variants it covers, P-51C, P-51D and P-51K. Somehow the P-51B was left off.
They make a vertical fin extension kit you can get.

Taller tail.

Butch

Odd they did not send even a few of the the H to Korea.

Logistics kept the H from Korea. The supply of parts for the D and F4U were vast.

When that war started there were a large number of P-51s in storage in Japan left over from WWII. Many more in the US.
Many thousands of the P-51D were built compared to 555 of the H.
The P-51D was used in Ground Support Missions. The H would’ve been a better dog fighter than the D but didn’t have any improvement in Ground Attack.
The loss rate was very high in this role. Both the Navy F4U-4 and the USAF P-51D suffered a nearly identical loss rate in the Ground Attack mission. With Chinese supplied Radar Guided Flak weapons and Proximity Fuse Ammo it made ground attack a difficult job.