(CAD) 28 Cyl P&W R-4360

[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

Once again I’ll add some of my interest and dealings. I built a 1/5 give or take scale model of a Corsair. f4u-1d. At the time I debated whether to make it an F2 G . It would have allowed adding about an inch to the nose. Which would have been easy just by moving the cowl forward. I hsdnot completed it at the time so I was unsure how much nose weight it needed or where to put it. It had a very nice blend of radius just behind the cowl that I think really helped reduce drag. I say this as it was considerably faster than the zero of the same scale and every bit as fast as the bearcat. Adding the inch rudder extension would have helped handling too. I didn’t know this at the time as big scale Corsairs were not popular then. I finally ran across a guy with the exact same plan set but he had done the conversion. He had a slightly more powerful engine however being a semi pro drag racer I managed to wring out more power out of my motor than Mose at the time. His plane had more gap around the cowl so the cowl flaps were more out in the breeze. I was into fluid dynamics then at my job so I did do some analysis of this. I was the only one using this software where I worked so I didn’t have anyone to challenge my results. Directly. Another guy had a Sea Fury of the same scale and in a simulated pylon race I couldn’t get away from him but he couldn’t pass me either. Thinking back had I left the 3 pounds off and re radiused the nose of the fuselage. I think the speed would have been even better. The plane weighed 38 pounds so 3 pounds would have been very significant. The plane flew very much like the full size lots of right rudder on take off. Interesting ly in talking to my father in law who flew thes during the war noted a special flaf setting for combat. He said he never really understood the theory of it but it did allow very high degree turns. I added a flap setting to simulate this . One of the scale manuvers required in scale flight demos in contests was a very high g sustained turn. Full size hav special instrumentation for this. It enabled the Corsair to out fly the zero under exacting conditions Other than zoom and boom. I practiced with this quite a bit and won 5 events so became the club “ace” The scale zero was not even in out league once I got this down. Pilot turns were spectacular with my extra speed. I never entered the warbird pylon races but it would have been competitive I feel. I flew this plane for 13 years before retiring it due to my health issues. It still exist in my son’s closet. Anyway I always wanted to try the bigger engine as I was sure I could coax more power than most out of it but they were just too expensive then.
I recently noted that the 4360 began experiencing bearing failure after high g turns so it was something else to add to this “major engine. It apparently was solved but not really put to the test in high performance fighters.
I have some ideas on the crankshaft construction since I don’t think the model could develope the dynamics of the full size as the relative strength of it doesn’t really ”scale”. A model just couldn’t develope the kenitic energy by vibration the way the full size did.
I’ll have plans in a week or so for the 18 cyl so I’ll start cad models from them an work in parallel with the 28 cyl. Model. It’s very complicated in model size let alone manufacture or build it. A scale plastic model is my dream for shop” for now. My. Hodgson will probably have to black my calls as he knows more about thes than I’ll ever forget.

Byron.

 

[Bentwings]

Once again I’ll add some of my interest and dealings. I built a 1/5 give or take scale model of a Corsair. f4u-1d. At the time I debated whether to make it an F2 G . It would have allowed adding about an inch to the nose. Which would have been easy just by moving the cowl forward. I hsdnot completed it at the time so I was unsure how much nose weight it needed or where to put it. It had a very nice blend of radius just behind the cowl that I think really helped reduce drag. I say this as it was considerably faster than the zero of the same scale and every bit as fast as the bearcat. Adding the inch rudder extension would have helped handling too. I didn’t know this at the time as big scale Corsairs were not popular then. I finally ran across a guy with the exact same plan set but he had done the conversion. He had a slightly more powerful engine however being a semi pro drag racer I managed to wring out more power out of my motor than Mose at the time. His plane had more gap around the cowl so the cowl flaps were more out in the breeze. I was into fluid dynamics then at my job so I did do some analysis of this. I was the only one using this software where I worked so I didn’t have anyone to challenge my results. Directly. Another guy had a Sea Fury of the same scale and in a simulated pylon race I couldn’t get away from him but he couldn’t pass me either. Thinking back had I left the 3 pounds off and re radiused the nose of the fuselage. I think the speed would have been even better. The plane weighed 38 pounds so 3 pounds would have been very significant. The plane flew very much like the full size lots of right rudder on take off. Interesting ly in talking to my father in law who flew thes during the war noted a special flaf setting for combat. He said he never really understood the theory of it but it did allow very high degree turns. I added a flap setting to simulate this . One of the scale manuvers required in scale flight demos in contests was a very high g sustained turn. Full size hav special instrumentation for this. It enabled the Corsair to out fly the zero under exacting conditions Other than zoom and boom. I practiced with this quite a bit and won 5 events so became the club “ace” The scale zero was not even in out league once I got this down. Pilot turns were spectacular with my extra speed. I never entered the warbird pylon races but it would have been competitive I feel. I flew this plane for 13 years before retiring it due to my health issues. It still exist in my son’s closet. Anyway I always wanted to try the bigger engine as I was sure I could coax more power than most out of it but they were just too expensive then.
I recently noted that the 4360 began experiencing bearing failure after high g turns so it was something else to add to this “major engine. It apparently was solved but not really put to the test in high performance fighters.
I have some ideas on the crankshaft construction since I don’t think the model could develope the dynamics of the full size as the relative strength of it doesn’t really ”scale”. A model just couldn’t develope the kenitic energy by vibration the way the full size did.
I’ll have plans in a week or so for the 18 cyl so I’ll start cad models from them an work in parallel with the 28 cyl. Model. It’s very complicated in model size let alone manufacture or build it. A scale plastic model is my dream for shop” for now. My. Hodgson will probably have to black my calls as he knows more about thes than I’ll ever forget.

Byron.

I’m sorry for my poor spelling. I have a medical condition that leaves me with double vision . So typing is extremely difficult. I have to squint some times and even closing one eye doesn’t help. In the shop I have to be very careful too.
thanks
byron

 

[SmithDoor]

in past and think how a two cycle wood worked.
Today they are building very large ship engines using 2 cycle.
Fewer parts almost twice the power per cylinder.

Dave

 

[Bentwings]

I suppose with 18 cylinders going up and dow you would have a relatively even vacuum. However gas carbs depend on the strong vacuum pulse to pull fuel from the tank.there have been many two stroke radials made from two stroke rods and pistons so it might work. It’s a lo5 of work making a crankcase plus making the crankshaft would be an issue too. Most small engine like rc models have pressed together cranks often with a roller bearing at bothe ends. So a pressed crank would not be out of the question just a lot of precision work for an unknown engine
OShad a 5 cyl for awhile sail makes a nice 3 cyl radial that’s glow operated.
probably the best thing would be to model it up in cad so you could see issues befor they happen. You could purchase most cylinders but they get expensive fast. Nant have very tight fitting pistons some even stick at top dead center until warmed up.
i just got my Hodgson plans for the 18 cylinder engines.there is a lot of work in these engines. I’ll know more about it as I get into modeling the parts. The drawings are pretty clear. There are just a lot of individual parts that have multiples. Just making the fixtures and special tools are a major undertaking. I dropped the plan set when the page clip came apart. Just picking up the pages an sorting them correctly took my entire lunch time and I live alone. Fortunately as language became pretty corse.LOL

 

[Steamchick]

Big ship engines that are 2-strokes are Diesel (often using heavy oil, that is solid at room temperature and needs melting!). Thus they use turbo-charging BLOWERS to force the air into the cylinders, not crankcase pumping, and also have high pressure direct fuel injection... so no carburetors.
Incidentally, Carbs do not use crankcase vacuum directly to draw-in the fuel. The crankcase vacuum draws in the air, which develops a partial vacuum (actually this should be described as sub-atmospheric pressure) in the venturi because the air as accelerated and faster flowing gas has a lower pressure... Thus the normal air pressure pushes the fuel upwards from the float chamber into the venturi to mix with the flowing air. Small Aero-engines just have a needle valve as the air is fast enough through the small inlet port to draw-in the fuel from the tank at almost the same level as the jet.
Sorry to be pedantic about this, but you made a supposition about the Ship engines that seemed a bit "off-beam. I'm sure you know a lot more about the small Aero-engines than I do so I'll accept any corrections gladly!
K

 

[SmithDoor]

It some I look at and wonder why very small or very large.

They made a few truck engines 2 cycle.

It seems like a great place for cycle to replace large aircraft engines is 2 cycle.

Dave

Big ship engines that are 2-strokes are Diesel (often using heavy oil, that is solid at room temperature and needs melting!). Thus they use turbo-charging BLOWERS to force the air into the cylinders, not crankcase pumping, and also have high pressure direct fuel injection... so no carburetors.
Incidentally, Carbs do not use crankcase vacuum directly to draw-in the fuel. The crankcase vacuum draws in the air, which develops a partial vacuum (actually this should be described as sub-atmospheric pressure) in the venturi because the air as accelerated and faster flowing gas has a lower pressure... Thus the normal air pressure pushes the fuel upwards from the float chamber into the venturi to mix with the flowing air. Small Aero-engines just have a needle valve as the air is fast enough through the small inlet port to draw-in the fuel from the tank at almost the same level as the jet.
Sorry to be pedantic about this, but you made a supposition about the Ship engines that seemed a bit "off-beam. I'm sure you know a lot more about the small Aero-engines than I do so I'll accept any corrections gladly!
K

 

[Bentwings]

Big ship engines that are 2-strokes are Diesel (often using heavy oil, that is solid at room temperature and needs melting!). Thus they use turbo-charging BLOWERS to force the air into the cylinders, not crankcase pumping, and also have high pressure direct fuel injection... so no carburetors.
Incidentally, Carbs do not use crankcase vacuum directly to draw-in the fuel. The crankcase vacuum draws in the air, which develops a partial vacuum (actually this should be described as sub-atmospheric pressure) in the venturi because the air as accelerated and faster flowing gas has a lower pressure... Thus the normal air pressure pushes the fuel upwards from the float chamber into the venturi to mix with the flowing air. Small Aero-engines just have a needle valve as the air is fast enough through the small inlet port to draw-in the fuel from the tank at almost the same level as the jet.
Sorry to be pedantic about this, but you made a supposition about the Ship engines that seemed a bit "off-beam. I'm sure you know a lot more about the small Aero-engines than I do so I'll accept any corrections gladly!
K

Small stroke engines use the crank case vacuum pulses to operate a fuel pump. This allows the chainsaw to operate in any position.sorry if I wasn’t clear on this. Some model engines us this to operate a pulse controlled fuel pump . I’ve use$ these many times on very high performance model engines. Another way to get fuel to the carb is to take pressure from the exhaust to the fuel tank thus forcing fuel to the carb. The needle valve then controls mixing as you noted. I’ve never put a pressure gage on to measure it but bu without it the engines don5 run very well. It’s usually one of the first things to check if there is poor performance on these rngines. Gas carbs have a port or separate line to the crankcase. By having very slight forced fuel feed these small engines can be very reliable.. yard equipment are good examples. Tillitson And Waldron carbs are used extensively.
super sizing these probably wouldn’t work very well. There are already many automotive carbs that woto fine until, emmisions become an issue then electronic fuel injection takes over. There are aftermarket systems that work fine.

but that’s all getting away from big two strokes. There are some pretty big snowmobile engines as well as the super bike engines.there are still a few two strokes around but the Eli has made the four strokes king. Just look at the new outboard marine engines. They are extremely powerful and reliable.

 

[SmithDoor]

The truck and ship engines uses a super charger for the air. The crankcase is oil bath.
Far fewer parts than a 4 cycle engine.

The first 2 cycle used a oil bath crankcase and a cylinder for air intake and one the compress the air for combustion. Still few parts over same size 4 cycle engine.

Dave

Small stroke engines use the crank case vacuum pulses to operate a fuel pump. This allows the chainsaw to operate in any position.sorry if I wasn’t clear on this. Some model engines us this to operate a pulse controlled fuel pump . I’ve use$ these many times on very high performance model engines. Another way to get fuel to the carb is to take pressure from the exhaust to the fuel tank thus forcing fuel to the carb. The needle valve then controls mixing as you noted. I’ve never put a pressure gage on to measure it but bu without it the engines don5 run very well. It’s usually one of the first things to check if there is poor performance on these rngines. Gas carbs have a port or separate line to the crankcase. By having very slight forced fuel feed these small engines can be very reliable.. yard equipment are good examples. Tillitson And Waldron carbs are used extensively.
super sizing these probably wouldn’t work very well. There are already many automotive carbs that woto fine until, emmisions become an issue then electronic fuel injection takes over. There are aftermarket systems that work fine.

but that’s all getting away from big two strokes. There are some pretty big snowmobile engines as well as the super bike engines.there are still a few two strokes around but the Eli has made the four strokes king. Just look at the new outboard marine engines. They are extremely powerful and reliable.

 

[Bentwings]

This thread is pretty old but extremely interesting.

to the original thread starter,,,,afte4 reading your interest and beginnings I’d strongly recommend obtain8ng a set of Lee Hogson’s 18 cylinder model. He has a very good knowledge of building the model as well as a lifetime machinist. Exile not exact scale he has created a great expandable design. He has als explored many alternat solutions to problems and many of these engines are completed and very functional. I think along the way things dont always ”scale” exactly. Metallurgy is one I know well After 35 years of engineering and 25 years as toolmaker. I also build and fly giant scale rc warbirds. Dealing with scale factors is intrinsic with this.

do get a set of drawings to continue your quest. You may want to visit Tom maker site for some great construction and machining solutions.

byron Nelson.

 

[SmithDoor]

I would hate to all that time in a RC plane and then fly the model.
My background is have built and fly RC planes and a hobby rebuild old engines. My living for over 40 years was manufacturring aircraft hangar doors.

I have always wonder why large full size aircraft have not used the two cycle engines.
A engine like the P & W R-4360 has so many parts and if was manufacturring as two cycle it would be a lot fewer parts and lighter.
Most only think of two cycle as oil burning not a big engine that does not burn oil.

Today they are using two cycle for very large ships.

Dave

This thread is pretty old but extremely interesting.

to the original thread starter,,,,afte4 reading your interest and beginnings I’d strongly recommend obtain8ng a set of Lee Hogson’s 18 cylinder model. He has a very good knowledge of building the model as well as a lifetime machinist. Exile not exact scale he has created a great expandable design. He has als explored many alternat solutions to problems and many of these engines are completed and very functional. I think along the way things dont always ”scale” exactly. Metallurgy is one I know well After 35 years of engineering and 25 years as toolmaker. I also build and fly giant scale rc warbirds. Dealing with scale factors is intrinsic with this.

do get a set of drawings to continue your quest. You may want to visit Tom maker site for some great construction and machining solutions.

byron Nelson.

 

[Peter Twissell]

The Junkers Jumo engines were 2 stroke diesels - used in aircraft sizes up to the huge Blohm and Voss bomber Wiking.
Ship 2 stroke diesels are very heavy, which doesn't matter so much in a ship, but in an aircraft you need a good kW/Kg ratio.
The Jumos had respectable power to weight, but were just as complex as a four stroke, with dual crankshafts and opposed pistons.

 

[Bentwings]

My Corsair took a while to build due to family moves. One thing many rc scale builders don’t do is research the full scale flight characteristics. They don’t always “scale exactly”but often are close. It’s easy to have more than enough power in these models so dealing with this is an issue. But as we say, that’s what the throttle is for. I could not get anyone to help fly it the first time so I flew it myself using known flight issues. They were notorious for excess York on takeoff requiring heavy rudder input especially in windy weather. I did exactly as the full size on carrier take offs with nearly full right rudder. In flight it flew very scale like. I won 5 scale events I entered in 5 different states. I flew it 13 years before retiring it to one of my sons. Who still has it. It never had a crash and only one dead stick with minor damage. These big rc scale plans don’t take kindly to being horsed off the ground just as full size plans don’t. Today there are corsairs with big 5 cylinder radial engines that are a real marvel to see and hear. There are some big two stroke engines that can really haul these around.
I don’t think it would be easy to build a light enough 18 cyl engine to fly 1/4 scale model. Maybe extensive use of unobtanium. Would do it.LOL I’m just getting started on cad model 18 cyl radial. I’ll have to finish this first before going far on the 28 cyl.cad model. There are many road blocks before even starting. I’m still learning history of development of the 4360. I can’t even imagine the engineering hours that went into it. Just cad models will take forever.
byron

 

[Cogsy]

I heard some reports a few years ago of ultra-light type aircraft using 'traditional' 2-stroke engines and having engine failures. What seemed to be happening was when they were descending they'd throttle back to idle and set up a descent rate, however if the descent rate was slightly too high the prop would be driven by the airflow and the engine would turn at a higher rpm than idle - but would not be receiving enough oil at the idle fuel rate to sustain the higher rpm. From what I read, generally when they went to throttle back up the engine would seize from a sustained lack of lubrication.

 

[ddmckee54]

That engine was built in the days when a pocket calculator would have been a 6" slide rule and a piece of scratch paper. I've still got my 10" log-log slide rule, somewhere, and if I scratched my head long enough I could probably even remember how to use it.

I guess that's why they built full-sized mock-ups of everything.

Don

 

[Bentwings]

That engine was built in the days when a pocket calculator would have been a 6" slide rule and a piece of scratch paper. I've still got my 10" log-log slide rule, somewhere, and if I scratched my head long enough I could probably even remember how to use it.

I guess that's why they built full-sized mock-ups of everything.

Don

that’s interesting. When I decide to go back to engineering school I had an instructor who was a marathon runner for metallurgy. He came into class and jumped on the table like it was a stepping stone and pointed to the large yellow teaching slide rule hanging over the chalk board. He look the group over then pointed to the slide rule and asked if anyone knew what it was pointing at me he said you don’t answer. I was a good 10 years senior to the class. Then again pointing at me he said explain what this is. So I did then he said find the sq roof of 9. Well easy enough but it took a few seconds to recall the moves. He very good now let’s get into metallurgy. He often had us do presentations on our work in front of the class then gave very pointed critiques of them. You had to be prepared in his class. I did get an A in the class and had many hours of“teaching
“ my findings and experiences in lab work. It was probably the best class I had in the 5 years at school. Standing in front of the group answering pointed questions and occasional challenges was extremely valuable in the following years in my engineering career.

 

[SmithDoor]

it was German they ever thing complex Junkers Jumo 205 - Wikipedia
This is how simple a two cycle diesel

Dave

 

[SmithDoor]

I have know idea why the Germans made a simple engine complex .
Yesterday I posted a photo how simple a large 2 cycle are done.
The photo just showed today.

I had a Detroit 2 cycle engine in a large forklift it work great.

Dave

The Junkers Jumo engines were 2 stroke diesels - used in aircraft sizes up to the huge Blohm and Voss bomber Wiking.
Ship 2 stroke diesels are very heavy, which doesn't matter so much in a ship, but in an aircraft you need a good kW/Kg ratio.
The Jumos had respectable power to weight, but were just as complex as a four stroke, with dual crankshafts and opposed pistons.

 

[ddmckee54]

I always thought that the Germans over-engineered everything in WWII, then I saw what Rolls-Royce did with the Merlin. I forget how may thousand parts it takes to build just one engine. It ALMOST makes the R-4360 look simple.

Don

 

[Peter Twissell]

There are a number of reasons behind the Jumo design. Among them were the lack of high octane fuel in WW2 Germany and the shortage of nickel for making valves and seats.
The Jumo is a highly efficient uniflow engine. In my opinion, it was an appropriate solution to the problem.

 

[Bentwings]

Ray-
not derailing my thread at all =) I love to hear the stories. I've heard it said that at a META power check in a maintenance hanger, if you were standing in the wrong spot you would be struggling just to breathe...one day I hope to experience the real thing, but until then, this is what I have =)

- Ryan

it appears that it’s been awhile since you last posted so many of ure waiting on your progress.

i spent many years building scale model rc aircraft. Along the way I discovered that many things don’t “scale” very well and are often mis scaled in terms of reality. For example aircraft panel joints or lines. There are few openings in panel that are 1/8”this means at 1/4 scal the opening or gap could be 1/32”. That’s barely a scratch on a 1/4 scale model. I used a sharp exactly knife and flex straight edges to draw scale skin joints. My big Corsair was to be shown as a fresh out of the factory plane thus a nice shiny blue finish. I put as many lines as I had accurate measurements of. I viewed many CAF Corsairs over the country from 20 feet even flying ones had almost no panel lines. Even cowl line were barely visible front gear doors had leather hinges so I used scraps from a fine leather purse for mine. model pilots were very hard to find . Any preprinted one looked like dead pilots so I had my artist wife paint mine with me as the model. Operating details just don’t scale well. You can have man6 pictures of cockpit instruments but they just never look right.
now to real hard ware . Engines don’t come anywhere near scale . Most of these planes were grossly overpowered. My father in-law flew the planes so I constantly asked about flying them. They could take off in 60-80 feet under the right conditions. Our flying field was about 200 feet so more than enough for a real one to take off. Bu5 to be scale looking it took pilot skills to keep it on the ground going straight with full right rudder. Full throttle was not scale at all. To be scale you had to just nurse the throttle barely clearing the weeds. The first event I entered I scored high in scale appearance an near perfect in flight performance. We had to do at least 5 scale maneuvers using the field centerline. The final high speed pass strafing run had both USMC vets Who were judges bailing out of their chairs They said except for no real bullets flying about that it was just like the beaches. It’s nearly impossible to scale a carrier landing but a nice 3 point from almost stalled won the event.
I would suggest you get Lee Hodgson’ plan set and use his bore and stroke numbers. This will get you relatively easy dimensions and easier parts to make. He shows many fixtures and tools required. It’s no small project even with these. The crankshaft will be a real project in itself. Again a lot of this does not “scale” easily. Just putting the crankcase parts together so the bearing bores all line up will be a trick. It’s a long ways to get the pieces to fit as precisely as needed. It might be best to align hone them. Not all automotive shops have hones to do this. Even line boring is a long ways. You might be able to do it on a Bridgeport with some special supports. Things are pretty small in this scale. Valves and seats are tiny plus it takes a lot of them....all the Same.
please keep us posted on progress.