P 51-H (2 Viewers)

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Beware of one VERY significant change made as result of extending fuse 13". The 1/4 chord line moved from approx 133" inches from tip of nose to 139 1/4".It had the effect of seemingly moving the entire cockpit forward of 'normal'. This was necessary to maintain similar stability derivatives while adding the 50gal fuse tank. There were no aft cg issues with the H.
Extremely important information! Thank you I did not know this . It creates a n interesting situation . Do I make the H as a D model with new wing shape or do I assume the model H designer took this into account? I'd guess not not but once plansre blown up I can check . Then what to do about it? I'm thinking I can make a sub wing mount that would allow for two different positions or I migh be able to make a more complicated adjustable mount. Our old aerobatic planes had this feature as guys were sorting out new planes . The wing could be moved just like the kids gliders . However even back then we were talking 100 mph models so trim errors could get out of hand in a hurry. I can see we are into some real serious thing here . I YHINK two wing saddles might bevthecway to go . These big warbirds usually follow the 1/3 cord rule give or take an inch. But this may be more than that . I'm not going to build an in-flight thing but more try it and see. Maybe a foam full size model glider . I guess I'll just have to hold on until I get the model plans laid out and see just where this puts things . I can't thank you enough for this! It may have saved a very bad crash. Already had that , don't need another.
 
Extremely important information! Thank you I did not know this . It creates a n interesting situation . Do I make the H as a D model with new wing shape or do I assume the model H designer took this into account? I'd guess not not but once plansre blown up I can check . Then what to do about it? I'm thinking I can make a sub wing mount that would allow for two different positions or I migh be able to make a more complicated adjustable mount. Our old aerobatic planes had this feature as guys were sorting out new planes . The wing could be moved just like the kids gliders . However even back then we were talking 100 mph models so trim errors could get out of hand in a hurry. I can see we are into some real serious thing here . I YHINK two wing saddles might bevthecway to go . These big warbirds usually follow the 1/3 cord rule give or take an inch. But this may be more than that . I'm not going to build an in-flight thing but more try it and see. Maybe a foam full size model glider . I guess I'll just have to hold on until I get the model plans laid out and see just where this puts things . I can't thank you enough for this! It may have saved a very bad crash. Already had that , don't need another.
The H wing position at 25%MAC was dictated to prevent aft cg condition due to 50gal fuse tank,

The empennage dimensions and area - specifically the H.Stab were also larger for the P-51H over NA-73 through NA-122. The vertical dimension from bottom of cooling system cowl to top of canopy is greater. The Wing MAC chord dimension is slightly greater

There really is nothing in common between the H and the D airframe.
 
The H wing position at 25%MAC was dictated to prevent aft cg condition due to 50gal fuse tank,

The empennage dimensions and area - specifically the H.Stab were also larger for the P-51H over NA-73 through NA-122. The vertical dimension from bottom of cooling system cowl to top of canopy is greater. The Wing MAC chord dimension is slightly greater

There really is nothing in common between the H and the D airframe.
I'll also check the stab too. The D model plans I have are well proven Rc planes I realize the full size had the big fuel tank . The only thing we have in the tail section is the tail wheel mechanics , these are pretty light as they mechanically operated by or servo operated by serv mounted just under the pilot seat if my H plans when enlarged come out close to the D size hot stab I'll be inclined to leave it as the B and D series plan planes are noted good flyers I might possible be able to come up with some additional blue prints . The plan D models were most often powered by heave gas engines so noe weight was not a problem . Keeping the tail light was an issue . The elev and rudder control horns were 2/4" wire so very heavy for model . They could be made from aluminum but the sharp bends make using higher alloy kinda tough torsionally they don't need steel material . I did some testing when I built the crashed model. I don't remember why I stuc with the steel wire . Most likely because there was to be a heavy gas motor . When we got rid of all the excess up front and gas motor we lightened the nose considerably even with the dual lipo batteries it was balanced right on the plan target value . I guess I'll have wait and see how construction goes . The model D designer does vey good Rc models the firt 120" B 125 flew perfect the first few fights with no additional ballast weight 50 pound plane .

Thanks forvthe additional information . I'll be adding it to my file.
 
We are just starting anew Rc giant scale 1/5 P 51-H. I have secured plans and permission to enlarge and copy them one issue is " how much taller is the H model rudder. " all I can find is " significantly large " no numbers we think the plans are incorrect wingspan and length seem ok . Belly scoop needs some modification too but we have good views views of it
Hi, the tail was changed for the production like M mjfur did show in pictures. That is why some manuals/sources list different tail sizes.
You can check the NACA document explaining the changes: Measurements of the Lateral and Directional Stability and Control Characteristics of a P-51H Airplane (AAF No. 44-64164) - NASA Technical Reports Server (NTRS)
And it also has some nice measures/drawings that you might like:

20050028482-0015.png

20050028482-0013.png


20050028482-0011.png
20050028482-0014.png
 
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The H wing position at 25%MAC was dictated to prevent aft cg condition due to 50gal fuse tank,

The empennage dimensions and area - specifically the H.Stab were also larger for the P-51H over NA-73 through NA-122. The vertical dimension from bottom of cooling system cowl to top of canopy is greater. The Wing MAC chord dimension is slightly greater

There really is nothing in common between the H and the D airframe.
There are almost no Rc model plans available other than what I have also no plastic model kits other than the one from china that wanted my life information. Scale Rc competition is usual done but supplying documentation for scale features overall appearance craftsman ship then scale flight maneuvers including taxing take off and landing. I've had to demo various features like bomb drop or tank release ,sliding canopy, all control surfaces. Landing gear. Corsairs with folding wings have a huge advantage as do bearcats with scale retracts. Speed is judged as if it looks good it is good . Modern air shows limit full size air speed but wartime was as fast as needed so you have latitude there . Speed is very controversial. Engine sound and props ripping air seem to help. I made a perfect 10 l carrier landing out of a dark rain squall for a big win at one meet years ago. One of the boys ran out and simulated unhooking the cable then directed me to the mid ship elevator which was the middle runway exit . That was quite an ad lib by the boys. Watch too many videos Lol
 
There are almost no Rc model plans available other than what I have also no plastic model kits other than the one from china that wanted my life information.
I assume you mean the Modelsvit 1/48 kit: you shouldn't need to go through too many hoops to get one. It's also been very well reviewed.
 
Hi, the tail was changed for the production like M mjfur did show in pictures. That is why some manuals/sources list different tail sizes.
You can check the NACA document explaining the changes: https://ntrs.nasa.gov/api/citations/20050028482/downloads/20050028482.pdf
And it also has some nice measures/drawings that you might like:

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View attachment 768751View attachment 768748
Oh my gosh thank you ! I missed this drawing initially. This will really help once I get the the plans enlarged . I'll redraw the entire rudder to fit the actual scale size . I'm pretty sure that by the time the H model flew the tail surfaces were covered with the new " dural" aluminum . Not sure what this by today's standard but probably 2024t6 the few notes I've seen mention it is not easily welded but flush riveted. I YHINK it might be able to be resistance welded Iultra sonic had not been invented back then. I use thin carbon fiber pultrusions between wing skins now so trailing edges are almost knife sharp yet can stand a few bumps in the shop . With all this I'm getting really excited. I hate to ask for more room in the family home as I'm just gramps taking up space as it is . I just need a bit more building space .

Anyway I really appreciate all the interest in this project.
 
Oh my gosh thank you ! I missed this drawing initially. This will really help once I get the the plans enlarged . I'll redraw the entire rudder to fit the actual scale size . I'm pretty sure that by the time the H model flew the tail surfaces were covered with the new " dural" aluminum . Not sure what this by today's standard but probably 2024t6 the few notes I've seen mention it is not easily welded but flush riveted. I YHINK it might be able to be resistance welded Iultra sonic had not been invented back then. I use thin carbon fiber pultrusions between wing skins now so trailing edges are almost knife sharp yet can stand a few bumps in the shop . With all this I'm getting really excited. I hate to ask for more room in the family home as I'm just gramps taking up space as it is . I just need a bit more building space .

Anyway I really appreciate all the interest in this project.
Mmh maybe in the Structural repair Instructions you find what you are searching for, page 80: Avialogs: Aviation Library - AN 01-60JF-3 Structural repair Instructions for P-51H Airplane
It is a 1945 manual so it is not updated on sizes but it is free.
1710441020413.png

Also outdated from 1945 but free the Erection and Maintenance Instructions page 44 Avialogs: Aviation Library - AN 01-60JF-2 Erection and Maintenance Instructions for Army Model P-51H
 
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That link on the NTRS paper on the P-51H does not seem to work. This one does:

 
That link on the NTRS paper on the P-51H does not seem to work. This one does:

Weird, seems like their server is down. Thanks
 
That link on the NTRS paper on the P-51H does not seem to work. This one does:

Thanks awaiting print enlargements
 
We just took prints over for enlargements once I get them back I'll begin modifying the general outline profile . Then I'll have to cut up at lest one set to make
Make building plans. Then this will go back for a real solid copy print. Then the real work begins . I just received some icyures of H models from nat guard unit s good friend served in I guess he didn't know what they were other than something special. We have not chosen a finish scheme yet waiting on completion . I have a bunch of special materials ordered. One thing I don't have is my structural analysis program I had in industry . So I'll have to go on past experiences . It won't be bullet proof but there will be plenty of armor . In carbon fiber. I can say for sure it will be possible to stand on the wing. So there won't be any " g" load limit . We just got a brand new radio top of the line. We have a servo test board set up to test all servonfunctions . Earlier last week the mfg ofvthe retractable landing ger announced they are stopping production of gear and only supplying parts on hand . Fortunately there is one other good mfg so we may purchase gear from them although we have a full operational set now. I've made arrangement to have any spare parts made as needed so we are covered .

That's it for this up date .
Bentwings
 
I did get the subscription. So I'm looking through it for dimensions. Our " model air force" is manpower limited so we can't crank out models like WW 2. I hope I live long enough to see what we have fly . Looks like we will " front half" the remains of the D model I'll design with minimum weight in mind as the gas engine is long gone. spinners are expensive but available as are carbon fiber props. So they are next on the list to purchase . I'm very disappointed that the H plans are not as good as I had hoped about the only things even close are the square vertical front lower belly scoop and smaller chin scoop opening neither are correct proportion by a long ways . So I'll have to revert to some old drafting things. I hope I remember enough . The H model was " slightly narrower in many notes but actual numbers have been evasive. The closest I've come amounts to around 1/2 to 3/4 inch on the model scale vs the D width . I means lofting the bulkheads from the firewall back to the tail wheel mount. A lot of work for something almost un noticeable in model size. I did find wheel/tire diameter. Model size is available however the retract mfg that closed the doors also made nice scale wheels including tires. . There are correct diameter model ones but not good scale. So I'll be looking in model friends to see if anyone is interested in making aluminum rims . Funny I ran across a picture of H models outside a factory with wood rims.and tires. Rubber was in short supply so apparently the factory temporarily used wood wheels to move planes about . Back to tedium work. Thanks for all the help and direction .
 
I agree. The looks of the H are just off in some way, IMO.
Yeah I have to agree however we are not deterred our big Rc H model is still on the board just ready to cut parts. I'm going to reduce the D wing less the "kinks to the wheel wells by 4% to further reduce drag. Also doing some aerodynamic work inside the belly scoop for drag too. We are doing some super scale stuff. I have 6 scale Browing ANM2 machine guns and ammo belts. I'm lacking ammo box details . For static display I'll have a motorized ammo belt drive and I'm thinking I might make the short recoil action of the barrels operate. we will have bright LEDS for gun fire and shuts to drop biodegradable plastic simulated casings in flight as guns fire. The guns take up a lot of room just as full size so wing redesign is necessary . Much of this and the D restoration will be carbon fiber A new endeavor for us. I've already secured titanium fasteners for everything bolted together. Probably an unnecessary expense. The electric belt drive and LIPO batts are about 2 pounds less than the gas motor but make 15shaft hp. It will turn the 4 blade a scale aero prod prop fast enough that we have to program a governor to limit prop tip speed to sub super sonic . Projected weigh is less than 25 pounds.With thrust t bout 45 pounds so the plane should be a real performer. Once we get started I'll try an post pictures.

Bentwings
 
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