[Guest]

For those of you who haven't seen my more recent posts, I've been talking about the P-51K quite a bit. So, I did some more research on the propellor. Here's what I found about the Aeroproducts propellors used on the P-51K-NT and P-51H-NA. Let's start at the beginning. The P-51K-1NT was about equivalent to the P-51D-15NA as far as loadouts and equipment go except for the Aeroproducts propellor. This propellor was made of 11', made of hollow steel, and designed to be a more than equal substitute than the Hamilton Standard props that were being used on all other Mustangs at the time. Unfortunately, as everyone tends to know, it came out poorly and hindered performance of the P-51K-1NT. The same poorly made props were then used on the P-51K-5NT which was based off the P-51D-20NA and used the K-14 gunsight. When in the field, both of these P-51K Mustangs had their props switched out for Hamilton Standards by ground crews. These were used mostly in Europe and the early P-51K variants were almost exclusively used by the 357th FG. It was also in this theatre that the P-51K, like the P-38J, gained it's notority for being an inferior plane. Yet, by the third variation, the P-51K-10NT, which was based off the P-51D-25NA and carried the same loadouts, the prop issues had been sorted out and the P-51K-10NT and it was now superior in performance to the P-51D and was being almost exclusively, if not exclusively, delivered to the Pacific where long-range Mustang escorts were badly needed. Then came the fourth and final variation of the P-51K, the P-51K-15NT, which was based on the P-51D-30NA. On to the P-51H... Basically, hollow steel, 11' 1" Aeroproducts propellors based on the ones used in the late P-51K's having only been lenghtnened by one inch, lightened, and widened, were used on all variants of the P-51H: P-51H-1NA, P-51H-5NA, and P-51H-10NA. As a side note, they would have also been used on the P-51M-NT and the P-51L-NA had they gone into major production. These Aeroproducts props on the F-51K's were used in Korea, although some were switched out for cuffless Hamilton Standard props as were almost all cuffed props on the F-51D's.

A few side notes... Contrary to popular belief, the Dallas canopies were not used solely on the P-51K-NT, but were also applied to Dallas build P-51D-NT planes as well. Both types of canopies were used on both variants depending only on what mill run of canopies were applied to them. I recently said on the Mustang Collection that the P-51K-5NT, P-51K-10NT, and P-51K-15NT should be built. This would be so that everyone could experience the poorer performance of the earlier P-51K's and the superior performance of the later P-51K's while being able to use the loadouts of the P-51D-20NA, P-51D-25NA, and P-51D-30NA on the P-51K's respectively.

I think that just about covers all of my research from the past couple of days for now. If you have any questions or if Lt. Wolf is lurking out there and wants to have a chat, please let me know...

[FeiHu]

As a P-51 fan myself,I would love to fly them all.To have all variants avialable would be awesome.Thanks for the research!

[elbarto]

deac, i hate to bust your bubble but the props used on -51k's and h's were entirely different.

http://www.mustangsmustangs.com/p-51/p5 ... -51K.shtml

http://www.mustangsmustangs.com/p-51/p5 ... 5NA_1.html

the -51k's prop was based more on the curtiss electric prop than anything else, whereas the h's prop was literally a cut off version of that used on the corsair and later on the skyraider.

too, the triangular aeroproducts prop used in korea was another iteration of that used on early k's as an attempt to maximize the thrust developed at the tip, this is not to say that the original design was bad, it just wasn't big enough to utilize the horsepower available, which is why the h model used such a broad prop to begin with, seeing as how it developed 500 hp more than a -7 merlin.

[Guest]

Uh, okay, but no... The Curtiss Electric prop was used a three-blade 10' 9' prop and was used on the P-51A. I don't know how you thought this was what the P-51K Aeroproducts prop was based off of, especially based on your sources. Sure, they may have similar looking blades, but they are entirely different props. The P-51K prop was something entirely new from the Aeroproducts company to be a better alternative to the Hamilton Standard props that were in short supply. Triangular Aeroproducts props in Korea? I don't know if you are trying to refer to a three-blade prop or the shape of the cuffless Hamilton standard props used in Korea. I did make a few mistakes in my original post about the Aeroproducts prop used on the P-51H, but it was in no way based on the Corsair prop seeing as the only Aeroproducts prop used by the Corsairs having been a contra-rotating one on the XF4U-4. Hamilton Standard props were used on all major production variants of the F4U, so sorry, but no again. Just because the props look similar, doesn't mean they are related. Aeroproducts made a totally new prop for the P-51K that eventually evolved into the one used on the P-51H. Nice try though...

[elbarto]

first of all, drop the sarcasm, it isn't necessary. you were right about the fact that production corsairs didn't use aeroproducts props, what i should have said was that the -51hs' prop was based on the f8f bearcats' prop and a still larger version was used on the skyraider. you were also right about the uncuffed ham standard, my apologies, HUGE brainfart.

anyway, the reason i say that the curtiss electric prop and that used on the -51k were alike is because they were both designed in the same era to do the same thing in the same way. what i mean by this is that they both tried to control how much hp was turned into thrust at certain points of the span of the blade for a given hp by having very dramatic changes in pitch at 10, 30, and 50% of span. this is why for the most part it didn't work well on -51k's because there was too much hp for these blades to absorb (despite the fact that the p-51k had four blades, 1100 hp / 3 = 366.7 hp vs. 1700 hp / 4 = 425 hp, this 60 hp per blade difference effectively doomed any hope of that prop performing better than the ham standard unless retwisted to better accommadate the hp).

now, why i say that the aeroproducts props used on the -51k and -51h respectively aren't related is because they try to do two entirely different things in two very different ways for two entirely different hp values. the k's prop was designed for the allison engine in the '30's to, as i said before, control how much hp was converted to thrust per given point of span for a specific hp. the -51h prop design differed because it was developed in the mid -40's and drew from lessons learned from german aircraft, also from 10% span out the pitch change was an almost linear curve, this was also true of the chord of the prop from 10% of span to the tip. the design philosophy here was much simpler in that it was used to convert as much hp to thrust wherever it could. kind of a "beat the air into submission" ideaology.

my original post was not to bash you or your research, i'm thrilled that there are more people out there trying (ain't easy to find hard data) to do serious research on these topics. i'm interested to know your sources of information. perhaps there is something i've missed in my studies that you've found.

[RedChico]

Rest assured that all members doing the P-51's have the necessary sources.
The only thing you need to worry is to have patience and wait for them.

[Guest]

Okay, I wasn't being sarcastic so you can drop that one. The F8F prop was 12' 4" and was made before that of the P-51H. So, naturally, the P-51H prop would have pulled data from the F8F prop and other props that had been made by Aeroproducts, but it had a strong geneaology in the P-51K prop. Now, sure, there was some data from German aircraft during the wartime that was collected by the Allies, but until the war was over data was scarce. The P-51H was developed, flew, and deployed to units during the war, just missing combat so you can pretty much dispell much thought of the P-51H prop being significantly influenced by German designs. Just because the Curtiss Electric prop for the P-51A and the Aeroproducts prop for the P-51K were, as you say, designed to do the same thing, doesn't mean they were related. To say so would be to say that the development of the Me 262 and the Gloster Meteor were related when they were obviously not. About the performance of the K... I have no idea where you are getting your data from, but the Merlin used in the P-51D/K produced 1,490hp. Besides, your math is pointless... The problem with the Aeroproducts P-51K propellor was not the design, as that was based off of extensive research provided to Aeroproducts. The prop was designed to do a better job with less materials and production time. The problems with it came from not having these props properly balanced during production resulting in vibration issues during flight. Aeroproducts went back, reworked the balance issues and subsequently the vibration issues went away on the late models starting with the P-51K-10NT. Then, for once the prop was actually better than the one it was designed to replace. The point is that by the time they got to the Pacific, they were actually better performers than the standard P-51D just as the Mustang IV was. Oh, my sources... Well, I've been basing all this off of numerous books, studies, service records, pictures, etc... Anything I could get my hands on. Do you really need my sources, cause it's a long list that takes a while to dig up again? I have been led to draw these conclusions on my own through tons of data. Nowhere will it say that, yeah the late P-51K was better than your average D. Nowhere... Then again, you'd be hard pressed to find somewhere that says the Allison powered P-51A's were perferred to the later Mustangs too, but they were...

Red Chico:

Does your data prove support my conclusions that the early P-51K's were worse and the late P-51K's were better than the P-51D?

[elbarto]

if not sarcastic you certainly are indignant. the aeroproducts prop used on the -51h, bearcat and skyraider were of a common lineage the first iteration having been designed for use on the wright 3350 (its' use on the skyraider was coincidental) and scaled down for subsequent applications.

you have alot of good third hand info, but have you ever worked on these aircraft? ever talked to the engine developers? i've spent a great deal of my life working on warbirds and as such have learned quite a bit from the men involved with their development and restoration. not to mention the guys that flew them and the few that still do.

the 1490 hp you're talking about is take off power, not war emergency, which was a little less than 1700.

go ahead and say what you like, but i am done arguing with you, if you don't want to learn from my experience and share some of your source material there's no point continuing the conversation.

[Guest]

I don't know what your problem is, but I'm not angry in the least... Didn't I just say that all of those props pulled from each other? Third hand info? All of my info is first rate coming from the actual Aeroproducts design records, field records, and pilot reports. There's just alot of it so it would be rather tedious to post it all here. Oh yeah, you can come back down to earth sir and be a bit more professional in your posts... Congratulations about working on warbirds and talking to people, but that doesn't make you an instant expert on everything about them. Pilots can be bias and wartime performance of a plane can be alot better then peace time performance depending on the upkeep of the birds in the two scenarios. Plus, it all depends on the plane too... A good number of P-47M's were hot rodded to do speeds over 500mph when the plane is only supposed to do 473mph. Okay, so I was wrong about the horsepower numberrs, but now you're telling me that you're estimating. I can make guesses too, but this is all about drawing conclusions. My conclusions, for the most part, aren't about the P-51H, but about the P-51K. In wartime, the P-51K-1NT and P-51K-5NT had poorer performance than their respective D counterparts due to unbalanced Aeroproducts props and had their props switched out for Hamilton Standards. The later P-51K-10NT and P-51K-15NT had the prop issues worked out due to improvements and revisions in production and they actually outperformed their respective D counterparts. Thank you for your contributions to this effort...