P-51H Elevators - same size as D model?

[LanceB]

I'm pretty sure the answer is "yes, the elevators were the same size", but the reason I ask is that as I was adjusting the horizontal tailplane roots on my HiPM H model to get rid of that sweepback they designed in, I was using 1/48 D-model drawings to get the angle right, and noticed the kit elevators were a LOT narrower in chord than the ones in the drawings. Overall shape and size of the horizontal stabs is fine, it's just the elevator chord that seems off. I think I should fill the hinge line and rescribe a new one further forward, but just wanted a second opinion. North American didn't re-engineer the elevators when they changed from fabric-skinned ones on the D to the H's metal-skinned ones, did they?

TIA

[Slartibartfast]

I'll check tonight on the chord.

I don't recall seeing anything indicating that fabric and metal surfaces weren't 100% interchangeable.

Can't reply until Monday, hope someone can help if timing is of the essence.

[LanceB]

I'll check tonight on the chord.

I don't recall seeing anything indicating that fabric and metal surfaces weren't 100% interchangeable.

Thanks, appreciate it. I did some more digging around, and found a 3-view of an H, the elevators look the same as the D, which would make sense. I can't see them (NA) souping up the Mustang and then decreasing control authority by shrinking the elevators. They would have had to increase elevator travel to compensate at lower speeds, and while metal skinned elevators would have taken the increased stresses of that better, it just seems simpler to leave everything the same chord and area. Still, I learned a long time ago never to underestimate the ability of a defense contractor to take the hard way around.

[Michael Vorrasi]

North American didn't re-engineer the elevators when they changed from fabric-skinned ones on the D to the H's metal-skinned ones, did they?

TIA

They are indeed totally different structures. The D and the H are structurally COMPLETELY different airplanes. Whereas all previous Mustangs were developments of the prior model, the H and other lightweight Mustangs share only the P-51 designation and general layout. The span of the horizontal tail plane on all production Mustangs from Allisons thru the B/C/D/K was 13 ft 2.13 in. and the area of the horizontal stabilizer was 28.43 S.F. and the area of the elevators was 13.02 S.F. On the P-51H the horizontal tailplane span was 14 ft. 10.156 in. and the area of the stab was 35.50 S.F.., while the area of the elevators was 12.85 S.F. Thus the H elevators are indeed smaller in square footage, while being longer in span, but your guess that this compromised elevator authority is not right because the entire airplane is different: The rear fuselage of an H is 13.5 inches longer, thus the tail plane is farther back in relationship to the CG, and thus a smaller elevator can be equal or greater in effectiveness. The P-51H tailplane was wider in span, had a higher aspect ratio and the hinge line of the elevator was located further back on the overall chord line. The HiPM kit tail you want to swap out isn't right, to be sure, but using a D model tail is equally incorrect. HTH.

Edited June 18, 2005 by Michael Vorrasi

[LanceB]

Hi Michael,

Thanks for those numbers. Now that I have those, I'll sit down and see just how far out the HiPM stabs are (aside from the obvious sweep issue) and where I need to go from here.

Thanks!