(CAD) 28 Cyl P&W R-4360

[Bentwings]

Ryan,

Not trying to dissuade you. I know where your coming from I can assure you. So does George and Steve.

I spent 13 years building a boat. If you want a bunch a people telling you "you'll never do that" or "Are you nuts?!"

Try building a steamboat....from the ground up. I got it worst from my siblings. I'm laughing now!

Home Model Engine Machinist Forum

If it's in your heart, go for it.

However, you did solicit comments...George was commenting, as was I.

Interesting thing about Forums...you only understand what has been typed

Glad you talked to Lee. The fixturing for the engines is tough to do from scratch. It's nice to get the drawing package with the manufacturing engineering done already! But I suspect you know that already.

We're a good bunch Ryan. We don't kick people when they're down, but help them up.

jump in and have fun.

Sincerely,

Dave

I had to dig deep to rediscover this build I think I posted very early on my thoughts since I had considered this right after I got my Hogson 18 cylinder plan set.
Since 28 cylinders don’t realy make a nice even rotation along crankcases my thought was to build 4 7 cylinders and link crankshafts together. There are jaw couplings to do this with urathane spiders to cushion loadings of cours some kind of engine to engine mount would have to be dreamed up and keyed so they fit easily timing would be at each engine as would cam set up . You could make metal coupler spiders too There are gear couplers that we used on the twin engine dragsters as wel as currently used on big race cars I’ve never seen one of these break. I even used industrial one on sever wire drawing machines I designed years ago they basically use a crowned gear inside a splined sleeve . I’ve seen some with plastic gear for lighter use too . This would indicate that it might be possible to have the corwned gear 3 d metal printed a little break in running would probably be a good idea so connecting the engines would not be a very hard project just a bunch more arts this project would be a massive group of parts but a couple guys have had cnc machines so that isn’t out of line it may even be a good excuse to update the shop. I’m too old and very dim eye sight so I’m out of business for maxing chips myself the doc says she will commit me if I get in the shop . I sold my TIG welder as I just could not see well enough to make precision welds any more. So the best I can do is ost thoughts .

One thing that took a terrible beating on the twin engine dragster was the crankshafts at first the front snout of the rear engine got ripped off as it not only had the front engine pouring close to 1000 hp into it but it had to use many hundred hp to drive the supercharger . We’ll much improved stronger cranks we’re made at far higher prices but that problem went away Clutches were initially a problem but solved by just adding another pair of discs two big Chrysler hemisphere make a lot of torque so rear ends were next but again just using a larger one fixed that then after market came out with even better solution simply more money . Twins were very exciting to watch and great crowd pleasers NHRA. Really shot them selves in the foot when the class was dropped . I had every thing ready to convert our single to twin almost a bolt in . Sold all the parts and helped build the new alcohol funnycar . Whole new experience as alcohol was not a well used fuel in drag racing at the time. Save this for later discussion . For a later time


Model 436. The full size was high tech turbo supercharged and had many problems if you have graham white book you can read about them . Model turbo and centrifugal blowers don’t work very well as the air flow does not scale well . There have been model scroll blowers made the were electrically driven but they have not done well either. Conley makes a semi scale roots supercharger that really works so I’d think about making something on that order . Mount the carb on the top of the blower and let it blow into the scroll ones on the engines you could make an over drive and run the positive displacement one faster so there would be much better fuel air distribution . Well I’ve rambled on too long so I’ll close for now. Byron

 

[Bentwings]

I appreciate the comments, folks. I really thought I'd made something clear, but I will try again.

I don't intend to jump into this as my first machining project. I don't expect to even have the CAD work done before I get my shop set up. I know this is ambitious, but I can' keep myself motivated unless I have something special to strive for.

Building this machine is certainly going to be nearly as daunting as designing it at scale. I understand it's not 'just numbers' but a great deal of it IS the numbers. My CAD program is incredibly powerful, and will give me the rest - i can run all of the simulations on it to determine if my numbers work... and redesigning a part in Inventor isn't much more than simply changing the numbers - it does the rest. For example, critical dimensions that might change, have been given a custom label. All other dimensions on ANY part that relies on that dimension uses the label in the formula. So, down the road if I find that my crankshaft's main diameter is too big, All I have to do is change the initial value for it, and everything else that relies on it, the openings in the crankcase, the bearings, the gears, will all change for me - and those that are 'purchased parts' will kick back an error if the new dimension isn't available.

My goal is to design this, while I gain my machining skills. I will be changing a lot as my skills evolve and I learn what can and can't be done. I will certainly build a few other engines before I tackle this one, and yes, 28 cylinders is a great deal of complexity. I am already working on designing a test rig for each cylinder. after each cylinder and piston is built, it'll be tested on its own as a one cylinder engine, before adding it to the 28 cylinder behemoth.

I'm even considering adapting plans for smaller radials to use the cylinders I come up with for the 4360 - this would let me build a few at a time, and if nothing in the design changes, use them later.

Re: Lee Hodgson - In a sense, he gave me the idea! I visited him personally at his shop in Cincinnati and saw his machines first hand. His father had begun work on designing the 4360, but ran into certain complexities and never finished the project. Those complexities were mostly in the very strange angles and offsets that are very hard to obtain - but with CNC, they should be quite doable. I respect Lee and all of his beautiful engines, and do fully expect to be building either the 14 or 18 double row from him before I start making chips for my 28.

I'm sorry to say it, but I won't be dissuaded! I have (hopefully, I'm only 31) a lot of years left to tweak and fine tune details if I must, but this machine will see life some day. I would hope that you all have experienced a project for which you had such dedication, and help me out when I stumble, on this one.

- Ryan

Hi again glad you are a “ youngster with drive.
I did a little more research on scroll blowers. If you look it up directly you should find the video of some model experiments the guy used a small leaf blower to work with . It was surprising how much pressure and velocity he could get he also made some mods to the volute and vanes. For practicality I YHINK you could team a couple stepper motor planetary units together for a higher overdrive ratio these are very cheap on Amazon snd don’t take much over to drive. I have several small ones I play with on my steam shop . They look nice too . Generally they are 2:1 or 3:1 ratio so you could get a pretty high OD in a small space the blower unit could be the same basic size just reshaped a bit. You could even compound them . I’d mount the carb on the inlet of the outer most unit. This would put air, fuel mix under some pressure in the intake but as we do on our street rods a simple spring loaded pop of valve is used to relieve back fires no pressure relief or other bypass needed. If you could get a couple psi manifold pressure I think these engines would be really fun . Exhaust valves need to be one piece stainless and valve seats might need to be silicone bronze. I don’t think I’d mess with dateline or other super hard seats as it’s hard enough to make them as it is . When w use aluminum heads the valve seats are shrink fitted so they don’t come out . I do the same on the model . Supercharging the engine would dramatically change the exhaust note. It would be worth looking into a little lar diameter pipes too. You will need to come up with a bender as I haven’t found anything for this small diameter as it is . You still would nee a material called cero bend t put in the pipes while bending so they don’t kink or collapse it’s a very low melting pint metal. It’s on Amazon or mc master car Very hot water melts it easily it’s pretty cheap and you would only need a pound or so as it is reusable. A 28 cyl is going to have lots of bent pipes for intake and exhaust. If you choose stainless tube it’s much more expensive and sizes are harder to get if you can get some seamless tubing like this from mc master carr but it is expensive . There are a few race car shops like mark Williams and chassis shop that have it but sizes are limited good vibrations racing may have some that is used for injector lines. You may have to invent your own port mounts and flanges fortunately both stainless and steel can be brazed with AC silicone bronze rod very easily . If I had my old eyesight I’d TIG weld it but that’s long gone now it can be TIG brazed but you need some one with talent and extreme patience 56 tiny pipes to connect would be taxing on the most stable of people. You still need an adaptor to the scroll blower . With cad you should be able to develope this . I just tried to open my solid works . I have the computer connected to a medium large screen tv with. HDMI port so I can see the text and icons but even with that it’s hard to see .
I YHINK before making a lot of chips I’d make a full cad model and either 3 d print it your self or send it out and have it pro done. This way you could see how things fit better I think . You could even do the scroll blower very nicely .
Anyway I’m leading the cheering section for you. I’d love see you complete this fascinating project.
Let me know your thoughts and ideas

Byron

 

[Bentwings]

I was going to suggest making your own bearings . Personally I stay away from the exotic stuff. Bearing bronze is easy to machine and more than strong enough. Our big supercharged hemi race engine use stock bearings locked just s small kinked area an a 3/26” bronze pin sticking up about 1/16” in the rods 2-3000 hp and these don’t spin unless no oil pressure. Even the mains just have the standard off set and are just clamped in .
Byron

 

[Bentwings]

Along with bearings and oil supply , on Hogson radials he uses a nic gear ump. We use similar one on the big hemi. Should you decide to go with 4 7 cyl I’d use the same idea but you can buy gear stock rod fro PM MANUFACTURING So you could easily make longer gears thus higher capacity . We use a so called dry sump oil pan there actually is a separate oil scavenge pump that picks up oil from the sump then sends it to an oil tank. The engine oil pump takes oil from this tank for engine oil pressure. The tank is a bunch larger than the oil pan as the scavenged oil is quite foamy it does settle fast however . The oil system takes a few lines but this is readily available . As a guide even on this relatively “small” engine I’d look for 100 psi minimum . You won’t be running 9000 rpm like we did but lots of oil pressure is lots better than no oil pressure. Just make sure the drive and shaft can carry the loads we use external belt driven oil pump . Back to the scroll blower as I noted the video I watched the guy worked with a pretty small leaf blower but compounding would give at least pressurized flow to each cylinder of well mixed air fuel . In industry I did quite a bit of flow with compressible fluids IE air and gasses it’s been a long time so I’ve forgotten a lot oF THE MATH math involved but simply put air with gasoline in it does not flow down small diameter tubes very well. It needs a” push” IE super charger .LOL

One other detail you noted was built up crankshaft. The R 28000 had a massive splined crank pin

Hi again glad you are a “ youngster with drive.
I did a little more research on scroll blowers. If you look it up directly you should find the video of some model experiments the guy used a small leaf blower to work with . It was surprising how much pressure and velocity he could get he also made some mods to the volute and vanes. For practicality I YHINK you could team a couple stepper motor planetary units together for a higher overdrive ratio these are very cheap on Amazon snd don’t take much over to drive. I have several small ones I play with on my steam shop . They look nice too . Generally they are 2:1 or 3:1 ratio so you could get a pretty high OD in a small space the blower unit could be the same basic size just reshaped a bit. You could even compound them . I’d mount the carb on the inlet of the outer most unit. This would put air, fuel mix under some pressure in the intake but as we do on our street rods a simple spring loaded pop of valve is used to relieve back fires no pressure relief or other bypass needed. If you could get a couple psi manifold pressure I think these engines would be really fun . Exhaust valves need to be one piece stainless and valve seats might need to be silicone bronze. I don’t think I’d mess with dateline or other super hard seats as it’s hard enough to make them as it is . When w use aluminum heads the valve seats are shrink fitted so they don’t come out . I do the same on the model . Supercharging the engine would dramatically change the exhaust note. It would be worth looking into a little lar diameter pipes too. You will need to come up with a bender as I haven’t found anything for this small diameter as it is . You still would nee a material called cero bend t put in the pipes while bending so they don’t kink or collapse it’s a very low melting pint metal. It’s on Amazon or mc master car Very hot water melts it easily it’s pretty cheap and you would only need a pound or so as it is reusable. A 28 cyl is going to have lots of bent pipes for intake and exhaust. If you choose stainless tube it’s much more expensive and sizes are harder to get if you can get some seamless tubing like this from mc master carr but it is expensive . There are a few race car shops like mark Williams and chassis shop that have it but sizes are limited good vibrations racing may have some that is used for injector lines. You may have to invent your own port mounts and flanges fortunately both stainless and steel can be brazed with AC silicone bronze rod very easily . If I had my old eyesight I’d TIG weld it but that’s long gone now it can be TIG brazed but you need some one with talent and extreme patience 56 tiny pipes to connect would be taxing on the most stable of people. You still need an adaptor to the scroll blower . With cad you should be able to develope this . I just tried to open my solid works . I have the computer connected to a medium large screen tv with. HDMI port so I can see the text and icons but even with that it’s hard to see .
I YHINK before making a lot of chips I’d make a full cad model and either 3 d print it your self or send it out and have it pro done. This way you could see how things fit better I think . You could even do the scroll blower very nicely .
Anyway I’m leading the cheering section for you. I’d love see you complete this fascinating project.
Let me know your thoughts and ideas

Byron

giving more thoughts. There are not a lot of deals on Hogson radials. Push rod and valve covers come to mind with high oil pressure it might be a very “wet” engine also as on the full size they go to some length to keep only a minimum of oil in the bottom pistons which can be any of course . I vaguely recall in the 4360 book that the pistons had drain holes so excess oil could drain out pat the oil rings . There also was a running and shut down proceedure to dump excess oil from the pistons that why I suggested the semi dry sump oil system it’s realy what they had anyway our race car oil systems are not true dry sump as there is little effort for oil and air separation. In the model it would be easy to do as we do just have a large enough “ settling tank” it’s not easy to get air out of oil in dry sumps ppppp

 

[Bentwings]

I to have a Pashto also interest intert in this engine. I would enjoy trading email and thoughts. Post if you would like to participate. I’ll try and watch here daily
byron

Regarding “ scale” I may have already noted this being a giant dcaleRc warbirds flyer, many things don’t really scale well a good one here is bore ad stroke. I’d be first to recommend staying with ageless radial bore and stroke. It’s a proven design two plugs per cylinder is ok but does really complicate ignition. By all means purchase electronic ignition . The rear scroll super charger really probably does nothing more than mix air and fuel also it only turns at engine speed so not very fast you could do external thing like I noted earlier. Not realy for supercharging but more to force the mixture down the small intake tubes I’m working on some planetary gear boxes with my little steam turbines to control generators and possibly a boiler pump. Mainly to give added torque as 75 K rpm I’ll have some torque to multiply model turbine are very week there .

I’ve seen only a couple model 5360 started but I don’t think any have been completed. I actually like the coupled 7 cylinders . You still have a lot of duplicate parts to make but the twisted odd angle crank case would be avoided. And making the scale crank shaft could be avoided . I don’t really think it would need all the scale movable counterweight stuff . Making that actually functional would take forever to design and build . It would be enough to just put plastic windows in the crank case and maybe clear rocker covers simulate a display engine sort of . Yet be operational.

If you really want a scale addition an operating constant speed prop would be neat even the Rc modelers don’t have them . There has been some tried but not very much success modern radios have enough electronics but it’s still complicated as a governor has to be incorporated the controls engine and prop speed relative to load or air speed . I’m not really up on exact function but on this type of project it could be done I YHINK at least you could feather it right at shut down . Another thing is fasteners one ofvthe start ups wanted to scale fasteners but there are lots of metric stuff that’s close I’d just use what ageless uses they are small enough You can get m2 metric if you want tiny I’ve got trays of the stuff and taps and dies I hate all of it. Me ofvthe startups had split connecting rods but I don’t know how it was done as the master rod doesn’t have much meat for this. I have to get my drawing set out again to check this out.

Anyway keep going. We are building another 120” b 25 so buried in its detail. I’m working on scale functioning exhaust as used on the later models. I don’t see well so I’m being teacher now that I can’t do the detail stuff I used to do. There will be some fancy brazing to do and each engine has its own format so two individual systems . I have only a few pictures as most have been converted to the original big exit pipes.

Byron

 

[Bentwings]

... It seems I woke up on the wrong side of the bed. (I was still IN bed when I wrote my last reply). I apologize if I was 'snarky' in my last reply. My life has been riddled with people telling me I can't do something, and nobody has ever told me I can. It seems everywhere I go, I meet with resistance. But I digress.

I am fully dedicated to making this thing run. It's been in my head for well over a year, and led me to many other radial engine designs that I have also toyed with in CAD while learning my CAD program as well as more about how the engines work. I've built the Edwards Radial 5 3 times in my CAD program now, making minor changes here and there so things worked better, and run all the simulations to ensure my changes didn't affect the running of the engine, etc. I have also done extensive reading on I.C. Engine design, and am fully familiar with the physics behind them.

As I did say earlier, I know better than to make this my first machining project. I agree, it's beyond my scope for now. I do intend to make the Edwards 5 (I haven't seen anything that makes me say "I can't figure out how to machine that") as one of my first projects, perhaps with a single-banger before that. Lee Hodgson's engines were suggested as a step up, and I've been considering those as well. I was leaning towards the 18 cylinder, but it seems the 14 cylinder will give me more information on the strange angles involved.

The biggest problem with the R4360 is that it's 4 rows. No other production radial engine is 4 rows. Others were developed, but never saw production. The added two rows add a ton of problems that can't be solved by gaining experience with one or two radials - even in a two row, the bearings and cams are on either end of the crankshaft... nothing has to worry about splitting bearings, splitting gears, and splitting the master rods (V8's might have to split the master rods, I'm not familiar with those - if anyone has a recommendation for a starter V8 I'd be glad to hear it). THAT is why I'm tackling the design phase now - the earlier I can identify the problems, the more time I have to figure out how to get around them.

Again, I apologize if I sounded snarky. This engine has become a dream of mine, and I was feeling rather defensive. I will see it through to the end, though it may take years. I will build my skills along the way, and probably make a million modifications to the design as I learn what will and won't work. I know it will be rough, but that's part of why it appeals to me - if anything, I am more determined to see something through, when I've been told "you can't" or "it's too hard" - I love to prove the naysayers wrong ;D

I've heard Bruce Satra may have made one but can't find anything on it, and only one other static, non-running model was made that I can find. This is entirely new waters, and I will be glad of any help you fine folks have.

I haven’t lost interest in this project . My addiction leaves me with no real energy fortunately I’ll be moving in with my son. He will be able to grab me by yhe hand and say let’s do something model wise . Lately we have continued planning on a resin 3D printer . He will have rooms and facility for this . So now something to look forward to. This in mine I YHINK I could either instruct or operate myself my solid works program. Ultimately I’d like to plan and model a 27 cyl radial . Not really scale except in number of cylinders.

Thinking about it 4 9 cylinders connected together . This would be a plastic fest top model . There are a number of obsticals in this but the cad program will allow use to design either a single crankshaft or connection devices . I don’t think the articulated balances that the real engine used would be needed in a model engine The proposed model can be electric motor driven and the cad will allow an animated model so we look at practical machining my plan is once we get this far I YHINK I’d just give the project to anyone that wanted to build it in metal. I’d guess it could be 3 d metal printed but I think the cost might be prohibited. Anyway should I continue being alive I would have a near daily project to do with the kick in the rear from my son and grand kids. So that’s my current thoughts . This fatigue thing is very hard to live with . Picture being exhausted all the time. I didn’t think I’d ever lose the internal drive and it’s very frustrating . Many get very depressed but at least I can read and investigate things to keep my mind active .

I’ve been very active Rc model flyer so we will continue this my don is already building a fleet of warbirds.

 

[Bentwings]

I haven’t lost interest in this project . My addiction leaves me with no real energy fortunately I’ll be moving in with my son. He will be able to grab me by yhe hand and say let’s do something model wise . Lately we have continued planning on a resin 3D printer . He will have rooms and facility for this . So now something to look forward to. This in mine I YHINK I could either instruct or operate myself my solid works program. Ultimately I’d like to plan and model a 27 cyl radial . Not really scale except in number of cylinders.

Thinking about it 4 9 cylinders connected together . This would be a plastic fest top model . There are a number of obsticals in this but the cad program will allow use to design either a single crankshaft or connection devices . I don’t think the articulated balances that the real engine used would be needed in a model engine The proposed model can be electric motor driven and the cad will allow an animated model so we look at practical machining my plan is once we get this far I YHINK I’d just give the project to anyone that wanted to build it in metal. I’d guess it could be 3 d metal printed but I think the cost might be prohibited. Anyway should I continue being alive I would have a near daily project to do with the kick in the rear from my son and grand kids. So that’s my current thoughts . This fatigue thing is very hard to live with . Picture being exhausted all the time. I didn’t think I’d ever lose the internal drive and it’s very frustrating . Many get very depressed but at least I can read and investigate things to keep my mind active .

I’ve been very active Rc model flyer so we will continue this my don is already building a fleet of warbirds.

When I read my previous post I nearly fell over the lovely spell check saw fit to to call affliction addiction. Entirely false I carefully edited it before posting and all was well once again I do not have addiction the med section notes a cancer which is true it’s not going to go away but may be less disabiling later. I have a doc review Monday that should tell the story. More later.

 

[Bentwings]

Well, I promised (threatened?) that I would start a WIP for my probably long-running design process for a scale Pratt & Whitney R-4360.

For anyone curious, the R-4360 is considered the largest piston engine to ever go into production for airplanes. It was used on a variety of aircraft at and after the end of World War II, and while thousands were manufactured, most were scrapped when the military no longer needed them due to the introduction of the jet age. Few remain, and fewer still are still flying. Most are in museums as static displays, many were even cut away to show the interior workings.

In the past couple of years I gained a sort of passionate love for this 28 cylinder radial engine that my girlfriend is probably a little jealous of. I have done a lot of research on the engine, and am always doing more. I feel the best way to show this beast a proper respect is to try and develop a working scale model.

Countless design decisions will be forthcoming, and I welcome input from all corners of the forum on anything that sounds or looks questionable. While I intend to build this behemoth of a model, I currently have no shop, no machines, and very rusty skills. If something looks like it will be impossible to machine, please don't hesitate to speak up.

The full-scale R-4360 sports some utterly astounding statistics. 4,363 cubic inches of displacement, 28 cylinders arranged in 4 rows of 7 cylinders, with 4 magnetos driving them. It 'sipped' upwards of 100 gallons of 108 octane fuel an hour (try that with today's prices!) all metered from a single pressure carburetor. Each cylinder sported a 5.75 inch bore with a 6 inch stroke, giving a 6.7:1 compression ratio and fired two spark plugs to ensure the cavernous compression chamber ignited evenly and fully. Intake ports were mounted on the top of the chamber, with exhaust out the side (analysis done since have suggested it would have been far more efficient to switch these two, and would have solved some of the intricate heat problems they had). This entire machine was air-cooled, requiring an astonishing amount of air to flow through the cooling fins, and indeed a lot of designs were tried to get the optimal cooling. The 3000-3500 horses were caged in a package that measured 55 inches in diameter and 96.5 inches long, weighing 3,870 pounds dry.

In military applications, the Wasp Major as it was known, was used in a variety of aircraft, from experimental to production. A list of aircraft that used this engine can be found on the following wikipedia article: Pratt & Whitney R-4360 Wasp Major - Wikipedia

Perhaps most notably was the F2G "Super" Corsair (Not the much more popular F4U Corsair, but very similar). Postwar, Several F2G's were converted into racers that dominated the air races until a tragic accident shut down the Unlimited Class until the 1960's. Since then, one Super Corsair named the Dreadnought took away numerous finishes, until it crashed in the mid 1980's. I believe Dreadnought is nearing rebuild, but that information may be inaccurate.

My goals with this design are to create a 1/6th scale version of the Wasp Major, though many design concessions will have to be made to ensure that it will be a running model. I will attempt to document the process of development, and as I am using a CAD program it should be easy for me to go back and make adjustments as required (provided I follow proper CAD procedures, something I often fail to do)

Again, if anyone sees anything questionable, has input, or any questions in general, please don't hesitate to jump in and help me. I apologize for this being a CAD work (for now!) and not a real machine, but some time down the road I will start another WIP when I have sufficient tools and skills to give the real thing a try.

Cheers,
- Ryan

I may have already posted regarding thoughts on the project. . I’m a long time Rc scale modeler and early on found that many things just don’t scale well . I too would like to have a”scale model of it . In my opinion I YHINK coupling 4 7 cyl engines together . There are all kinds of couplers that are plenty strong enough. In order to make it functional you need some king of air mover to just move the air fuel down the intake pipes . Call it a supercharger. So air fuel does not flow down small I’d tubes very well so it needs a push. There have been various superchargers attempted . Recently I saw a video of a guy that used a leaf blower impeller and he experimented with different scrolls designs . It was amazing how fast he. Hot air to move with small units . It would take a compound planetary gear system to get drive speed high enough but there are lots of stepper Moyer heat boxes that could be coupled pretty easily. If I ever model this I would definitely resin print the model first this involves lots of cad modeling but possible. Certainly easier than machining hard parts . You could have a desk top model driven by electric motor . Over driving these small planetary units can take some power but if the heavy grease is stripped out they run fine. From there you can decide if you want to rocerd . It would be very good to talk to Mr. Hogson st Agelless engines as he knows theissues well.

 

[Zeb]

We had a 4360 core in school. Pretty mind-boggling thinking about fuel air distribution and changing all those spark plugs! Would it be too much a compromise to run multiple carbs?

 

[Bentwings]

Crankshaft, Revision 0

After reading all of the fun language that is a patent, two sayings came to mind. One, I've heard a few times in the various places I've been reading about machining engines. The other is a fairly popular one. Nike's "Just Do It", and "Start with a chunk of metal, and machine off anything that doesn't look like a [insert part, in this case crankshaft]"

A Crankshaft is effectively a long cylinder, with additional cylinder offset from its center line by 1/2 the length of the stroke. Where these offsets are, the main cylinder is cut away, to permit the rod for that crank throw to pass through the crankshaft's center line (If it couldn't, your engine wouldn't run very long. Half a turn at most.)

I have no information to go by for how thick the rods are. But what seems like a good guess to me, is about half of the diameter of the piston. My pistons are 0.9583 inches bore, so I'll use 0.479... naw, we'll just make it a half inch thick. I can always drop it to 3/8's later if I need to. If my rods are a half inch thick then by necessity my master rod journals need to be a half inch long, perhaps slightly longer. I'll add 1/32th of an inch to either side as a sort of buffer. Now, the patent drawing for the sideview of the crankshaft (patent is no. 2,426,879, I'm referring to Figure 21) shows lots of fine details, but being a patent, doesn't have dimensions. One notable thing is that the centerline bearing journals are bigger than the master rod journals, thus the 'long cylinder in the middle' is bigger than the master rod pin diameter. I can infer from a scale, assuming the patent drawing is to scale, that the diameter at the bearing is about 35% larger than that of the master rod journal.

... I talk a lot.

Anyway, while measuring that tidbit I found that at the scale I happened to print this image, the width of the crankshaft master rod journal pins is actually a half inch. this is a bizarre coincidence, but I'll take what I'm given! I can use this to get some other basic measurements with ease.

Anyone who saw my original post in the Questions thread regarding split gears will understand that I'm going to likely run into issues if I make this a single piece crankshaft. For now, I will design it as single piece, because it will give me a better visual idea of how I might be able to split it for a multi piece.

A basic layup of all those 'cylinders':

Obviously something's missing - there's nothing nearly strong enough actually holding the m/r journals in place but a thin piece of metal. I did warn that it was a basic layup. Of note in the second image is that each row is offset by 180 degrees, plus the offset between cylinders, of 12+6/7 degrees. this works out to 192.85 and change degrees, which allows each bank to fire on the opposite side of the bank before it, thus evening out vibration. This will make more sense when we get to firing order much later. (A preview of the firing order is visible at http://moozorzica.com/engines/4360order.jpg)

After some basic touchup, we have something that looks a bit more like a basic crankshaft :

This seems workable for now, so I'll leave it at this. Being as this is the first part, it's subject to great changes... hopefully not too badly, though.

I tried to keep the design minimal. I could have done the interconnects in that crazy half-round style they like to do, but this method will be way easier to machine, and will also lend itself to breaking down into multipart easier.

Based on this, I have : master rod thickness: 0.5", master rod journal diameter 0.435", master bearing diameters 0.5", 1/32" buffer on either end of master rod journals, all appropriate angular offsets between rows, etc. The overall crankshaft ends up being 7.200" long in its present design.

Next up: master rods. These are two-piece designs, that clamp together around the master rod bearing (which are also split bearings but I am leaning towards a multipart crankshaft, in such a way that i can slip the m/r journal bearings in one piece, way cheaper that route) and will require attach points for the other 6 slave rods, in each row. The Wasp Major has two of these actually passing through the bolts that hold the m/r halves together, which I'm sure I can manage, but will require custom made bolts.

This is enough for tonight. Thoughts on whether this would be machinable as one piece? a lot of pieces? Think I'd just end up making a bunch of scrap pieces in the process? I'd love to hear from you.

Cheers,
- Ryan

As you have already found scale doesent always work to practicality fasteners coms to mind first. I would say adjust scale to practical size fasteners that are available there are lots of studs and nuts on this project maybe consider some what try to standardize if possible rod bolts particularly I would not use split rod. Cranks can be press fitted . Many small yard engines Han especially 2 strokes . I may have already noted valves are going to be micro sized. Probably stainless steel titanium as our race car valve would be very difficult to make . Iould use 4130 or 2140 for crank parts Le Hogson ageless engines has a plan set for the 5, 7 9, and 18 cyl radials I would suggest calling him an getting on or more of his drawings/ plan sets. To show you how to organize this he is full of knowledge . At you chosen size piston rings will be an issue just finishing the cylinders will be an issue . Maybe do ost to removable cyl head . Hogson actually has you make special assembly tools
.more later

 

[Bentwings]

Regarding “ scale” I may have already noted this being a giant dcaleRc warbirds flyer, many things don’t really scale well a good one here is bore ad stroke. I’d be first to recommend staying with ageless radial bore and stroke. It’s a proven design two plugs per cylinder is ok but does really complicate ignition. By all means purchase electronic ignition . The rear scroll super charger really probably does nothing more than mix air and fuel also it only turns at engine speed so not very fast you could do external thing like I noted earlier. Not realy for supercharging but more to force the mixture down the small intake tubes I’m working on some planetary gear boxes with my little steam turbines to control generators and possibly a boiler pump. Mainly to give added torque as 75 K rpm I’ll have some torque to multiply model turbine are very week there .

I’ve seen only a couple model 5360 started but I don’t think any have been completed. I actually like the coupled 7 cylinders . You still have a lot of duplicate parts to make but the twisted odd angle crank case would be avoided. And making the scale crank shaft could be avoided . I don’t really think it would need all the scale movable counterweight stuff . Making that actually functional would take forever to design and build . It would be enough to just put plastic windows in the crank case and maybe clear rocker covers simulate a display engine sort of . Yet be operational.

If you really want a scale addition an operating constant speed prop would be neat even the Rc modelers don’t have them . There has been some tried but not very much success modern radios have enough electronics but it’s still complicated as a governor has to be incorporated the controls engine and prop speed relative to load or air speed . I’m not really up on exact function but on this type of project it could be done I YHINK at least you could feather it right at shut down . Another thing is fasteners one ofvthe start ups wanted to scale fasteners but there are lots of metric stuff that’s close I’d just use what ageless uses they are small enough You can get m2 metric if you want tiny I’ve got trays of the stuff and taps and dies I hate all of it. Me ofvthe startups had split connecting rods but I don’t know how it was done as the master rod doesn’t have much meat for this. I have to get my drawing set out again to check this out.

Anyway keep going. We are building another 120” b 25 so buried in its detail. I’m working on scale functioning exhaust as used on the later models. I don’t see well so I’m being teacher now that I can’t do the detail stuff I used to do. There will be some fancy brazing to do and each engine has its own format so two individual systems . I have only a few pictures as most have been converted to the original big exit pipes.

Byron

I just came across c&h ignitions they can make any thing you want do ignitions should be easy I’ve used their products for years in my Rc warbirds with no issues . I just moved a couple that whole old worked gin when stored just need battery and switch connections it looked like the Hal effect was still in the engine hub. We may test some of my old engines shortly

I’ve been thinking about some kind of air mover forvthe sh lees engines I saved an electric leaf blower so I have a working scroll type blower it moved a lot of air once I get settled better I’m thinking of designing a planetary gear box to drive a blower it’s more to help push air down the small tube rather than supercharger Call it a fuel air mixer there have been a few made but I haven’t found the cad models . My don and I are getting ready to get into resin printing so this would be s good place to start . Long term I’d like to make s resin printed 2& cyl with s fee extra parts to make s 38 cyl out of 4 7 cyl engines the resin printer would allow proper coupler with barrel shaped gear teeth . These are incredibly strong even in plastic

The nice thing about resin printing is once a good print is made the complete set can be made at one time . The tolerances are ver good too so once you get a feel for them it not hard to make close fitting parts like pistons and cylinders and outright experimental parts . Vision is a desk top plastic model radial engine there used to be inexpensive one atvthe hobby shop but these are several hundred dollars for even the small one if you can find them they were Called visible engines in their day

 

[Bentwings]

Regarding “ scale” I may have already noted this being a giant dcaleRc warbirds flyer, many things don’t really scale well a good one here is bore ad stroke. I’d be first to recommend staying with ageless radial bore and stroke. It’s a proven design two plugs per cylinder is ok but does really complicate ignition. By all means purchase electronic ignition . The rear scroll super charger really probably does nothing more than mix air and fuel also it only turns at engine speed so not very fast you could do external thing like I noted earlier. Not realy for supercharging but more to force the mixture down the small intake tubes I’m working on some planetary gear boxes with my little steam turbines to control generators and possibly a boiler pump. Mainly to give added torque as 75 K rpm I’ll have some torque to multiply model turbine are very week there .

I’ve seen only a couple model 5360 started but I don’t think any have been completed. I actually like the coupled 7 cylinders . You still have a lot of duplicate parts to make but the twisted odd angle crank case would be avoided. And making the scale crank shaft could be avoided . I don’t really think it would need all the scale movable counterweight stuff . Making that actually functional would take forever to design and build . It would be enough to just put plastic windows in the crank case and maybe clear rocker covers simulate a display engine sort of . Yet be operational.

If you really want a scale addition an operating constant speed prop would be neat even the Rc modelers don’t have them . There has been some tried but not very much success modern radios have enough electronics but it’s still complicated as a governor has to be incorporated the controls engine and prop speed relative to load or air speed . I’m not really up on exact function but on this type of project it could be done I YHINK at least you could feather it right at shut down . Another thing is fasteners one ofvthe start ups wanted to scale fasteners but there are lots of metric stuff that’s close I’d just use what ageless uses they are small enough You can get m2 metric if you want tiny I’ve got trays of the stuff and taps and dies I hate all of it. Me ofvthe startups had split connecting rods but I don’t know how it was done as the master rod doesn’t have much meat for this. I have to get my drawing set out again to check this out.

Anyway keep going. We are building another 120” b 25 so buried in its detail. I’m working on scale functioning exhaust as used on the later models. I don’t see well so I’m being teacher now that I can’t do the detail stuff I used to do. There will be some fancy brazing to do and each engine has its own format so two individual systems . I have only a few pictures as most have been converted to the original big exit pipes.

Byron

I’ve done a bit more thinking on an air moving blower again a resin printed scroll type is best by using a number 27 stepper motor planetary gear turned around so it’s a gear up I YHINK you could get enough impeller speed to move a lot of air through those small intake tubes you cou still use s draw thru carb so you don’t havre to deal with making the carb pressurized you could even couple a pair of gear boxes up Not really looking to supercharge but just positive air moving there would be considerable air guel
Mix in system so for saftey sake a simple pop off valve like we used on our street rods and early dragster would be ok if there was a backfire . Model Rc four strokes use pretty standard small engine carbs tilleydon or walboro most any would work I’ve used both with no preference you just nee small pressure in fuel tank to make positive flow two strok law tools use crankcase pressure By posting there are all kinds of check valves svailable so you could easily vontrol tank pressure as needed . I might have a couple of these planetary drives. After just moving all my hobby stuff I’d packed up so I’ll get into it shortly I have some steam enginges so I’ll be able to operate them at about the radial operating speed We are planning on a resin printer and I’ll be getting my solid works back andvtummning son should be able to make some models and if nothing else send some stuff otnto be printed I’ve got at least 4 turbines soni coils generate some really high speed if necessary they don’t have a lot of torque but I have do couplings so I I don’t use steam bug I have a good air compressor that csn get them to 30 grand rpm if necessary can team them together eventually I’ll try and print a desk top radial as I have the ageless drawing set .
More

 

[peterl95124]

Regarding “ scale” I may have already noted this being a giant dcaleRc warbirds flyer, many things don’t really scale well a good one here is bore ad stroke.

Byron

Byron, read up on some of the other writings in this website concerning scaling laws and the physics of why some things scale and some things don't. bore and stroke do scale, any working engine's bore and stroke can be scaled just fine, its other things that don't scale well. Peter.

 

[Bentwings]

Byron, read up on some of the other writings in this website concerning scaling laws and the physics of why some things scale and some things don't. bore and stroke do scale, any working engine's bore and stroke can be scaled just fine, its other things that don't scale well. Peter.

I may have gone a bit over board here what I was referring to was the 5360 used two spark plugs per cylinder with a 5” bore give or take it’s probably necessary to build a good flame front but 2 plugs per cylinder on a 2” bore would be very difficult and not really necessary other than scale looks we ran 4.35 in bore hemi on alcohol at 8500 rpm plus with 30-30 psi boost using one plug per cyl. Nitro guys now use 2 plugs but have nearly full cylinders It takes 44 amps each to fire these. When you see the volume of fuel used it’s amazing.

I’m a long time hot toffee and known for pushing limits everywhere I did about everything to squeeze a couple hundred rpm out of my giant scale warbird engines . More than a few didn’t survive . I YHINK what I’m trying to get across is I love scale radials and wolf love to see a semi scali 4360 engine run I’ve searched but have yet to see any . There have been a few voumponded engines which is the direction I’d go . Air fuel delivery would be s problem so some type of blower/ super charger would be needed to force the mix down the small intake tubes . This means so experimental design and testing before the main construction begins in my mind. I’ve already looked into some of this as Rc model engines have had mini roots blower/superchargers I never could justify the cost of them There was a guy that scyualy made a printed screw super charger but it failed miserably by not being able to inflate s garbage bag I’d look toward something related to leaf blower. This would require some kind of planetary over drive gear box . It’s not too hard to find something like this on servo motors. I have about half a dozen I got just for this experimenting. I’ve just relocated so my hobby stuff is packed up seating te discovery! We are pretty close to gftting into resin printing so my plan is to come up with some kind of scroll blower. Others have done this with pretty good results The gear box would be relatively easy to install in the stock location you could even drive it by electric motor to save space . I end have at least 6 steam turbines that are capable of 100 grand rpm . They don’t have a lot of torque but being all metal could be exhaust driven like s turbo. That was not my purpose however if you have seen how complicated turbos were in warbird you probably would write this off as not scale able. And I’d agree but you might find it usable air especially with fuel in it does not like to flow down small tubes with bends. Just a note airfield in a closed system like this can go “ bang” do a pop off valve would be needed we had such a device on our alcohol racer and I used them on a number of supercharged street rods it just give s rapid vent in case you have a back fire . Anyway just analyze things befor scale ing apperance is one thing functionality is another.

Byron


V

 

[peterl95124]

I may have gone a bit over board here what I was referring to was the 5360 used two spark plugs per cylinder with a 5” bore give or take it’s probably necessary to build a good flame front but 2 plugs per cylinder on a 2” bore would be very difficult and not really necessary other than scale looks we ran 4.35 in bore hemi on alcohol at 8500 rpm plus with 30-30 psi boost using one plug per cyl. Nitro guys now use 2 plugs but have nearly full cylinders It takes 44 amps each to fire these. When you see the volume of fuel used it’s amazing.

Byron

check out my 1:5.4 scale Rolls Royce Merlin V12 on this website; 1" bores, four valves per cylinder and two (count em, 2) spark plugs per cylinder. anyway, also check out the various posts on the physics of scaling laws. Pete.

 

[Bentwings]

check out my 1:5.4 scale Rolls Royce Merlin V12 on this website; 1" bores, four valves per cylinder and two (count em, 2) spark plugs per cylinder. anyway, also check out the various posts on the physics of scaling laws. Pete.

Oh my gosh I can’t wait to view this. I may have to have my son help me as I have such limited vision it’s hard for me to even see the key board Jensen the spelling mistake beyond what spell check does.


I can’t really be critical after all it is scale . As in our big scale Rc planes some times if it looks scale it’s taken as gospel . A good example was my big Corsair gun sight . I had nothing to go on but video games so I took a piece of chest plastic a carefully scribed a cross hair and s circle on it and made some sort of scale mounts . Nearly everyone thought it was a perfect representation to go with my pilot in looking at pictures today of it I’m realy imbaraset that I displayed it and even Won 5 flying events with the plane so was awarded “ ACE”. We are building a new plane that will be much more scale. I’ve see only one operating scale model Merlin supposedly made from the casting kit that was available years ago very impressive model and machine work . I’m really looking forward to the 4360 radial. I don’t think there has been a model displayed at least not that I could find just modeling all the parts would be a huge project . I’ve rolled this around quite a bit. I may take this on as a resin printed project with my don. So only a dream now.

Back to dual plugs . I had opportunity to use an aluminum hemi head on our racer but turned it down as the heads were already noted for dropping valve seats thus most likely the engine as it turned out about a week after the offer the guy dropped a seat in his hemi and made a big mess of the rest of the engine . Those were Chrysler sponsored cars so cost was no object. We were not so endowed

But con grays on a beautiful construction

 

[Bentwings]

Erlll I started st sbout midnight asking questions on safari about things I only had white’s book background . Searches are easy. Just type in a question as you might ask a person I’ve already spent 30 + hours looking up 5360 stuff. It’s an amazing story .
A guy called Tom maker has modeled the ageless 28 cyl in ACAD I have use of solid works but it’s been a while so I’m just getting back into it I don’t have difknitive plans yet but I may do the same thing then resin print a desk top
Model . Just to be amazed at all the moving parts as fo s sole the real thing I can see lots of issues iv you have detailed drawings it won’t be too hard to make cad models then scale to you size . However after any entire night and now s good share if the following day “ researching” this big thing . If you lmlh have sn eyeful of observation then try to creat soMe part it at be about scale I probably looked at 100parts with no dimensions so this could be s daunting task at best. I’d certainly attempt to model all of ssgeless 28 cyl then plan how to use this in the 53$0 model. There ere do many problems in developing this engine that there could be a substantial library in addition to ehites book just on yhrm . Now would these surface in a scale or semi scale model . Only if one is built the crankshaft was probably hours of reading last night Being engineer myself I font find this even tiring. So far 80 yr old and 18 sleepless hours just had coffeeand toast for late breakfast

Not even tired grand kids have another double header softball games tonight. I’m not supposed do marathon things anymore But this is really fun .,….for me why do I need all this stuff packed into a dim brain ….. I don’t know if just seems like it’ssomeyhing I need to do . I’m noted as haveing a side effect of fatigue which is for me loss of drive internal drive to fo things that need doing So what ever I’m having fun that’s important for me .

There was a spectacular description of a 2800 coming apart in the dyno test cell it was pulling a full prop at full power and the crank broke . The pop hit the wall dead ahead and continued spinning until it stopped narrowly missing the observer.

So just ask questions be carful about getting roped into a program called just answere it’s a pay deal looking for you dollars.

 

[Bentwings]

Once again spell check tries to out guess me so just read into these things I’ve edited and corrected much but I still see stuff . Sorry about this.

 

[Bentwings]

I to have a Pashto also interest intert in this engine. I would enjoy trading email and thoughts. Post if you would like to participate. I’ll try and watch here daily
byron

Here is my email.

[email protected]

Byron

I’ve got Whites book right here on the coffee table.

I was really hoping I could get my Solid works program up and inning but I YHINK something got lost in my moves . We are trying out fusion 360. My don is already ahead of me. I just tell him what to look for in the various icons. It will take a while for me to transition. I’d really like to make a desktop resin printed model mayb about 1/5 scale so it would more o less fit in the new Corsair. It’s easy to make it an F 2g except for s couple aero dynamic features . Just for show. We have two big 2 stroke engines for the flying model. It will be a 100+ mph plane just as my old one was. Our Air Force now has a “ captured” Me 109 under restoration , P 51 D new, P 51 B under construction , a 120” B 25, I YHINK a J model so far in construction a Fokker tri plane , Cherokee light plane plans for P 61 black widow plans for SB2C helldiver and several others all are giant scale radio control models . My son is a ww2 history buff so All have background some even in the family. I even have a Leica 3 c camera that my dad came home with from Europe .

 

[Bentwings]

I had to dig deep to rediscover this build I think I posted very early on my thoughts since I had considered this right after I got my Hogson 18 cylinder plan set.
Since 28 cylinders don’t realy make a nice even rotation along crankcases my thought was to build 4 7 cylinders and link crankshafts together. There are jaw couplings to do this with urathane spiders to cushion loadings of cours some kind of engine to engine mount would have to be dreamed up and keyed so they fit easily timing would be at each engine as would cam set up . You could make metal coupler spiders too There are gear couplers that we used on the twin engine dragsters as wel as currently used on big race cars I’ve never seen one of these break. I even used industrial one on sever wire drawing machines I designed years ago they basically use a crowned gear inside a splined sleeve . I’ve seen some with plastic gear for lighter use too . This would indicate that it might be possible to have the corwned gear 3 d metal printed a little break in running would probably be a good idea so connecting the engines would not be a very hard project just a bunch more arts this project would be a massive group of parts but a couple guys have had cnc machines so that isn’t out of line it may even be a good excuse to update the shop. I’m too old and very dim eye sight so I’m out of business for maxing chips myself the doc says she will commit me if I get in the shop . I sold my TIG welder as I just could not see well enough to make precision welds any more. So the best I can do is ost thoughts .

One thing that took a terrible beating on the twin engine dragster was the crankshafts at first the front snout of the rear engine got ripped off as it not only had the front engine pouring close to 1000 hp into it but it had to use many hundred hp to drive the supercharger . We’ll much improved stronger cranks we’re made at far higher prices but that problem went away Clutches were initially a problem but solved by just adding another pair of discs two big Chrysler hemisphere make a lot of torque so rear ends were next but again just using a larger one fixed that then after market came out with even better solution simply more money . Twins were very exciting to watch and great crowd pleasers NHRA. Really shot them selves in the foot when the class was dropped . I had every thing ready to convert our single to twin almost a bolt in . Sold all the parts and helped build the new alcohol funnycar . Whole new experience as alcohol was not a well used fuel in drag racing at the time. Save this for later discussion . For a later time


Model 436. The full size was high tech turbo supercharged and had many problems if you have graham white book you can read about them . Model turbo and centrifugal blowers don’t work very well as the air flow does not scale well . There have been model scroll blowers made the were electrically driven but they have not done well either. Conley makes a semi scale roots supercharger that really works so I’d think about making something on that order . Mount the carb on the top of the blower and let it blow into the scroll ones on the engines you could make an over drive and run the positive displacement one faster so there would be much better fuel air distribution . Well I’ve rambled on too long so I’ll close for now. Byron

I may have already noted this comment . Last winter I got to visit a museum that happened to have several cut away R 4360 engines. I was amazed at how big the master rod bolts were as well as other fasteners on the engine. Once again, I recommend you carefully consider what a 1/6 size fastener of any size really is my don and I are avid Rc scale warbird builders often 1/4 scale or 1/5 scale We deviate from true scale airfoils to proven model stuff in the approximate size in these scale models( if it looks scale it is scale LOL ), to continue I do have the R 4360 book and have read it many times . I also have Hogson plans for 7 and 9 cyl engines . For your project I YHINK it would be best to plan on 4 7 cylinder engines connected together by flexible couplings available from M

Here is my email.

[email protected]

Byron

I’ve got Whites book right here on the coffee table.

I was really hoping I could get my Solid works program up and inning but I YHINK something got lost in my moves . We are trying out fusion 360. My don is already ahead of me. I just tell him what to look for in the various icons. It will take a while for me to transition. I’d really like to make a desktop resin printed model mayb about 1/5 scale so it would more o less fit in the new Corsair. It’s easy to make it an F 2g except for s couple aero dynamic features . Just for show. We have two big 2 stroke engines for the flying model. It will be a 100+ mph plane just as my old one was. Our Air Force now has a “ captured” Me 109 under restoration , P 51 D new, P 51 B under construction , a 120” B 25, I YHINK a J model so far in construction a Fokker tri plane , Cherokee light plane plans for P 61 black widow plans for SB2C helldiver and several others all are giant scale radio control models . My son is a ww2 history buff so All have background some even in the family. I even have a Leica 3 c camera that my dad came home with from Europe .