# P-51 Replica. It's a Slow Day, so Let's Design One.

### Help Support HomeBuiltAirplanes.com:

#### DanielLogan

##### Member
G'day Tom,
wow what an undertaking! I stumbled apon this thread on google. I am keen on replica fighters and am a little way into a ww1 nieuport 17 build, however thats rather stagnant. I just want to say keep up the good work! I have been throwing idea's around about a 80% Hurricane myself, however the Mustang has always attracted me. I completly understand your idas of Steel tube then covered in ALuminium. Jurca did it so it has to be able to be done, and as you have mentioned many times as has Titan. I would like to get in on the project with you one way or another. I am a LAME down under here in Australia (Licensed Aircraft Maintenance Engineer) A&P or IA in US terms. I have recently moved states for a job in a warbird maintenance shop. We maintain in house a P40, CAC 18 (Aussie built P-51) several AT-6's, T 28's. We do all fabrication ourselves so have all the gear. So I have complete access to a Mustang if you need reference shots etc. After reading through all 8 pages of reply's spanning over a year, an alternative to your design could be a comination of semi-monocoque and steel tube construction such as an aeroplane like the T-6. Just a thought.

Have you given any thoughts to the tail surfaces? In the planning of the Hurricane I like the idea's of using simple tryed methods, limiting the machining and custom extrutions if possible. Using simple methods like folded channels or extruded angles all easily available from aircraft material suppliers. For the horizontal tail for example I was planning on just using 0.050" or something folded in a U channel. Alternativly using just sheet 0.032" for the web and angle for the caps. Anyway, Orion may point out flaws in those theories, though I would like to hear what loads are placed on the horizontal tail and how one calculates that.
Daniel

#### Tom Kay

##### Well-Known Member
Hi Daniel;

Thanks for replying to this thread. My original title "Slow Day" was tongue-in-cheek, as it would take much more effort than a day to design this replica. But, that's obvious. I bounce ideas off forum members because of my own rudimentary background in Aerospace studies.

The P-51D is hard to ignore, as is the Spitfire. Unfortunately with the Spit, the total number of heavily curved parts adds a lot of challenge to the build, especially in metal. Parts of the Mustang would probably be easier, plus she's still a beauty to look at when complete. What has really thrown water on my Mustang fire is the cost and complexity of the engine/PSRU/prop combination, which is why I've focused more on the Murphy Renegade biplane lately. It's a far more reasonable beginner project. Simple engine, simple prop, no PSRU, basic construction. So that's where my head is lately, but I know that with the right kick, I'll get back to this at some point.

I kept vascilating between semi-monocoque and steel tube structure for the P-51 replica. My last approach was steel tube with cosmetic fuselage frames and skin, neither of which would be fully shear loaded as the original. Questions about skin wrinkling and expansion rates of steel vs aluminum are unanswered in my mind, but as we've both said, it's been done in the Titan and other aircraft. I don't see this as a show-stopper.

I am not familiar with the T6 structure at all. A tad more familiar with the Hurricane frame. What's the T6 like under the skin?

As for the tail, I had loosely planned on what you mentioned, some sort of web plus angles for the tail spar, ribs and skin. The spar might be do-able as one formed piece, but more likely a build up of 3 main parts (2 spar caps and a web). I hadn't really gotten that far in my thinking.

I have little or no ethical problem in using the ideas of other manufacturers or designs, because this type of borrowing goes on in every industry, and I would not be looking at marketing my results anyway.

So, what sort of effort would you be into? Actual building, or helping with design ideas?

The P-51 is hard to stay away from, and once built (well) I can see a number of advantages compared to a short-distance open-cockpit biplane. However the cost and complexity have me stymied for the moment. I'm not short on skill and patience, but I am on specific experience in metal forming, money and equipment. Well, 2 out of 5 ain't bad.

Cheers, Tom.

#### Tom Kay

##### Well-Known Member
I just did a search for Harvard and T6 inner shots, and I see now how it's built. Steel tube, with fuse frame formers, and a skin attached to the frames.

The biggest difference that I see with the Harvard, is that there is a whole skin panel that just bolts onto the frame. This panel has mini frames and stringers riveted onto it, presumably to keep the curved shape. Neat idea, and it might actually work as a single unit, better than skinning onto frames and stringers. I'd have to think about that a bit.

So again, I'm left with the concept that steel tube fuse and aluminum skin are very possible.

Tom.

#### Rienk

##### Well-Known Member
The P-51D is hard to ignore, as is the Spitfire. Unfortunately with the Spit, the total number of heavily curved parts adds a lot of challenge to the build, especially in metal. Parts of the Mustang would probably be easier, plus she's still a beauty to look at when complete. What has really thrown water on my Mustang fire is the cost and complexity of the engine/PSRU/prop combination,

I kept vascilating between semi-monocoque and steel tube structure for the P-51 replica.

I have little or no ethical problem in using the ideas of other manufacturers or designs, because this type of borrowing goes on in every industry, and I would not be looking at marketing my results anyway.

So, what sort of effort would you be into? Actual building, or helping with design ideas?

The P-51 is hard to stay away from, and once built (well) I can see a number of advantages compared to a short-distance open-cockpit biplane. However the cost and complexity have me stymied for the moment. I'm not short on skill and patience, but I am on specific experience in metal forming, money and equipment. Well, 2 out of 5 ain't bad.

Cheers, Tom.
For those who are interested, once we finish the original 'Solo' design Welcome to Ayerscraft we plan on doing several high performance "fighter" variants - including the Mustang, Corsair, Spitfire, and maybe a Hurricane, Zero, Messershmitt, Thunderbolt (depending on demand and cost of molds). They will be as close to scale as possible (tail volume is always the main problem).

They will all be powered by 120-150hp TC engine, most will be 1+1 seating (cramped back seat), and hopefully have retractable gear options.

Right now, it's just a dream - but one that is very feasible.
We will definitely need an initial build team committed before designing each additional model.

Oh yeah - they will all be outfitted with camera - laser fighting - smoke systems! :ban:

#### sketus

##### Member
Hey Rienk, i heard Stories like yours a million times! Fantasy stories i guess.
First of all there is a Viros on the page that you linkerd.
And second a question: heve you ever worked with composite materials?
...

#### Rienk

##### Well-Known Member
Hey Rienk, i heard Stories like yours a million times! Fantasy stories i guess.
First of all there is a Viros on the page that you linkerd.
And second a question: heve you ever worked with composite materials?
...
We've been working with composites for over ten years, in the wireless telecommunication industry, as well as aviation.

We have built dozens of composite aircraft - we own four right now - which we built... several from scratch.

The web page I listed (which has been checked for viruses) shows the design of one... and other than the cowlings, all the parts have been built, and the prototype is almost complete.

If you would like to see our other project, which is a COMPOSITE six-seat, executive propjet kitplane, feel free to go to Welcome to Sreya Aviation and check out the Envoy.

If you would like to see some of our other handiwork, check out Welcome to Chameleon Engineering
We've sold about $30 million of this stuff. For our 3D capabilities, you can look at Welcome to Stillwater Pictures to see some neat software we've written and sell (designed originally for our in-house studio, with current projects being a full length feature film and a childrens video series) Are those credentials enough for you to at least give us the benefit of the doubt? I don't mind skepticism... frankly, all these other models are "pipe dreams" until we finish the Solo and Duet... BUT, the concept was designed with replica fighters in mind eventually. BTW, we have a full scale splash off of a real p51 - accurate to the individual rivet heads and hangar rash (the donor aircraft ended up as a monument). We're already collecting 2D drawings of most the models listed, as well as buying or developing 3D models. I make no claims as to when we'll get to to any of these - just testing the waters to see what the interest is! #### Rienk ##### Well-Known Member Sketus, once you've had a chance to see what we can do, maybe you might want to collaborate instead of challenge? Sorry if I'm hijacking your thread Tom. #### sketus ##### Member Rienk, maybe i missjudged you. If so i am very sorry. I do not know whay my antivirus always detects a Virus/Worm on Welcome to Ayerscraft and also on Welcome to Chameleon Engineering I use avast! antivirus! Maybe just a problem with the script, not actualy a Virus. Regardles of that i have explored the pages, very nice airplanes the 6 seatter and also the solo are great! Keep up the good work. Cheers And yes sorry Tom... it's your thread #### Tom Kay ##### Well-Known Member That's OK gents, hijack away. I haven't exactly been filling this with Mustang details lately. Maybe one day. Cheers, and keep posting about any progress on your fighter replicas. Tom. #### Rienk ##### Well-Known Member That's OK gents, hijack away. I haven't exactly been filling this with Mustang details lately. Maybe one day. Cheers, and keep posting about any progress on your fighter replicas. Tom. Fighter replicas won't show up for quite a while :ermm: We still have to finish the Solo, THEN move on to the Duet (which presumably will be our bread and butter). After that, we can back track to the fun toys, and hopefully the 'war games' system will be developed (laser tag, smoke, and video capture). So much to do, so little time (actually, so little money - which can buy you more people's time) #### ScottAlexander ##### New Member Hey guys/girls. Im 18 and in college. Im designing a P-51 Mustang with my own variations of course. Im using Autodesk software (inventor and autocad) and am open to all kinda of tips, tricks, and helpful advice. I have some things done...mainly an idea and thats about all. -Scott #### Mac790 ##### Well-Known Member Im using Autodesk software (inventor and autocad) and am open to all kinda of tips, tricks, and helpful advice. I have an advice for you, probably not the one you are looking for, change software, as a student you have probably access to different CAD softwares, personally I would recomend Solidworks, it has much more powerful surface abilities than Inventor, you might want to check out an animation that I did about 3 years ago, just to prove that I know what I'm talking about, I know both softwares well. If I was going to design a reductor/gearbox I would choose Inventor, but for cars, planes, etc I would choose Solidworks, anytime. Don't get me wrong Inventor is also a really nice software, but not for that job. [video=youtube;-XCHwodME_8]http://www.youtube.com/watch?v=-XCHwodME_8[/video] Seb Last edited by a moderator: #### arcticserv ##### Active Member Hey Adrian, are you still offering those plans? I am designing/building a 82% scale dual p51d (tf) am moving slowly but still moving. Have a outer wing panel nearing completion, just waiting on some bits from the USA they take a while to get to Australia. Your plans could be helpful in ideas/ methods used in the fusalage. Shane #### ScottAlexander ##### New Member Thats a great animation, Ive done one similiar not a lotus seven but with a vice. As far as software goes. Ive been Inventor for 4 years. Ive used solidworks as well (only about 2 years) My main concern is frame construction. Not how to do it on the computer but how the thing goes together. Ill be able to build it in any software, but I'd like to know or see some pictures of past projects. Ive see others but Im inquiring about more and higher resolution. #### Tom Kay ##### Well-Known Member Hi Mustang Enthusiasts; It's been a very long time since I posted anything here. But I went back to a website that I bookmarked many months ago, and there has been huge progress. This is a website about a Tasmanian P-51 replica, not sure what scale, and there is some really good info here. I was really fascinated by his homemade prop hub, although I am guessing it's not variable pitch, inflight at least. Maybe ground adjustable. Still, being built in pieces, it looks like a doable thing. I have no idea if it would be strong enough not to fly apart due to centrifugal force. There is a huge gallery of pictures, so if you haven't seen this already, have a look. Scratch-built P51 Mustang Photo Gallery by Derek Slater at pbase.com I really appreciate when some builder takes the time to document what he makes, especially with so many pictures. Enjoy. Tom. #### Von Richter ##### Active Member The landing gear I used on my 5/8 scale P-38 was power "tilt" cylinders and Bendix pump used on Johnson outboard motors. It was easy, cheap, and super light. #### Tom Kay ##### Well-Known Member Hi Von Richter; I'd like to see what you used. Do you happen to have any pics of these cylinders? Also, remind me to never engage in a dogfight with you, or anyone else whose last name starts with "Von." Cheers, Tom. #### maxsmodels ##### Member I find it amazing that anyone has the ability, resources and 'stick-to-it' to build a full scale fighter. I am considering a box frame with foam shapers F-2A-3 Buffalo....someday. #### piepermd ##### Member Hello, wjst do you mean by a “full scale splash off” of the P-51? Thanks! We've been working with composites for over ten years, in the wireless telecommunication industry, as well as aviation. We have built dozens of composite aircraft - we own four right now - which we built... several from scratch. The web page I listed (which has been checked for viruses) shows the design of one... and other than the cowlings, all the parts have been built, and the prototype is almost complete. If you would like to see our other project, which is a COMPOSITE six-seat, executive propjet kitplane, feel free to go to Welcome to Sreya Aviation and check out the Envoy. If you would like to see some of our other handiwork, check out Welcome to Chameleon Engineering We've sold about$30 million of this stuff.

For our 3D capabilities, you can look at Welcome to Stillwater Pictures to see some neat software we've written and sell (designed originally for our in-house studio, with current projects being a full length feature film and a childrens video series)

Are those credentials enough for you to at least give us the benefit of the doubt?
I don't mind skepticism... frankly, all these other models are "pipe dreams" until we finish the Solo and Duet... BUT, the concept was designed with replica fighters in mind eventually.
BTW, we have a full scale splash off of a real p51 - accurate to the individual rivet heads and hangar rash (the donor aircraft ended up as a monument).
We're already collecting 2D drawings of most the models listed, as well as buying or developing 3D models. I make no claims as to when we'll get to to any of these - just testing the waters to see what the interest is!

2