GodBomber!

I had an idea[sm=idea.gif]! Some one has probably had the idea before or it is already created. But my Idea is to make a in line 4 cylinder engine! what do you think? would it work? I figure with the power it would have it would be an engine for prop racing. I had the idea when looking at my engine I thought it would be cool to take 4 engines and mold them into one! so is it possible?

CAPtain232

My Feedback: (40)

While your idea is very feasible, you have to realize the added weight that an inline 4 has vs an opposed 4 cylinder. Longer crank, crank case, more bearings due to the extra length, probably a substantial amount of additional weight just in the induction system as well. This may all have no meaning if you are thinking in terms of scale realism. Such as in a P-51 or something of that sort.

GodBomber!

I thought of that, and I don't think it would be a problem. Just get a large and long wing span it should fly right? I think it might cause a problem with fuel usage though, it would probably guzzle it like crazy!!

DBCherry

My Feedback: (4)

There are quite a few twin cylinder, and a few 4 cylinder engines out there (although I don't remember seeing an in-line 4), there are also 3, 5, 7 and 9 cylinder radials. Trying to reinvent the wheel usually isn't worth it.

But if you have the skills and the access to a machine shop, so that you can manufacture a new crankshaft, and make the needed modifications to the rest of the crankcase(s) and engine components, give it a shot!
Dennis-

GodBomber!

I don't have the skills personaly, but I know some people who can give it a shot. I'm an idealest not a builder, I think of the stuff and help build some of it.

greenboot

My Feedback: (1)

GodBomber,
You certainly have a lot of unique ideas and thoughts. I would like to know a little more about you. Are you a student? What type of other activities have you been involved in? Just wondering, you are an interesting person.

Tom

GodBomber!

What do you mean am I a student? A student in school or a student to planes? I know some about planes I want to learn more though. I love to build and invent things, I have always thought of myself as a inventor in the future. I have many ideas and many talents. hows about your self? I like to create many new things. I have so many ideas every day that it is very had to sort them out. sometimes it is hard and frustrating having all these ideas and no budget to do them with[:@]. why do you ask?

MinnFlyer

My Feedback: (4)

Can you say A.D.H.D.?


Actually, there's not much you can come up with that hasn't already been thought of.

You are new to this hobby. Think about how many inventive/creative people have been at this for YEARS.

Want a cool engine for a 1/4 Scale P-51? How about a 1/4 Scale version of the P-51's original Rolls Royce Merlin Engine?

Now THIS is creative!

ballgunner

My Feedback: (1)

At one time there was a four cylinder engine called the Ross. Ross was a machinest and the engines were purpose built as in-line fours not cobbled together from parts of other engines. Ross engines are very rare, a real collectors item. He also made single and twin cylinder engines. His son Herb had some his dad's engines but wouldn't part with them. I don't blame him. They were absolutely beautiful. Another modeler made a radial out of Cox cylinders and a homemade crankcase a few years back. It was advertised in some of the model magazines. Don't know what ever became of the project.

greenboot

My Feedback: (1)

GodBomber,
The reason I ask is because when reading these posts, I am always curious what kind of people are writing them. Your username and unusual ideas are very intriguing and make me wonder.

Since you asked, I am an engineer. Been working here at Boeing for 28 years. I've been in RC only 4 years.

Tom

GodBomber!

I see, I am different from every body else. I just want to learn to fly so bad! When I get older I want to learn to fly a real plane! that would be cool, take people up and give them tours for money on th side. I really like to build home made R/C cars. I have modified one once before, but now I'm making one from the body of a R/C battle bot car it is really cool looking so far. By the way, I don't want my engine to look like that! although it is very neat looking. I want mine to look like you took 4 of the same engine and molded them into one, it would have 4 separate heads on it.

R. C. Day

My Feedback: (7)

The first problem that I see is that you need to seal each piston/crankshaft/carb assembly from the others. Outboard boat motors (two stroke) are built the same way. The cylinders will share a common crankshaft, but needs to have there own atmosphere to build and maintain positive crankcase pressure.
R. C.

3DFanatic

My Feedback: (5)

Boeing for 28 years? DOnt know about there but here in WA that's a real accomplishment seeing as they lay off about half their workforce every December

Lightfoot

My Feedback: (1)

One real problem with this idea is that of cooling the rear cylinder. Each cylinder will dissipate its heat to the air flowing through the cooling fins, each heating the air progressivly. When the air reaches the rear cylinder, it is going to be relatively hot and may not have the required cooling capacity.

GodBomber!

what about a small water cooling system? Or liquid nitrate? if handled correctly it should work. And I think I found a way to fix the crank shaft so they are separate. Put walls in between each engine, then put a long spot on the shaft. You could use gaskets to seal one from a another.

MinnFlyer

My Feedback: (4)

Like I said...

If you find a cool idea that isn't being done, it doesn't mean it hasn't been though of or tried. It usually means that several people have wasted a lot of time and money only to discover that there are too many pitfalls, or there is a better way to do it.

Look at it this way, Why would you put two heads in line with each other when you can have them opposing each other? Now, the two pistons will counteract each other. Can you imagine the vibration of 4 pistons all on one side of the engine?

In other words, there are REASONS why you just don't see some products on the market.

Want another example?

Ever see a 4-stroke radial engine that has 4, 6, or 8 cylinders?

Nope, ALL 4-stroke radial engines have an odd number of cylinders (even Full Scale)

I could tell you why, or you could just accept it, or you could rack your brains and spend thousands of dollars to make one, only to find out that even if you succeeded, an using an odd-number would have been simpler.

So, why bother?

Nuker

Wow Mike,

that sounded kinda harsh []

I'm personally a firm believer in that there can always be a better way.

GodBomber has some ideas; probably needs research, might be wrong or maybe a new way is right etc etc but if people don't try and learn and try again, where would the hobby, or anything else for that matter, go? You don't waste time when you are learning something regardless.

Sorry if I'm reading it wrong, I'd just hate to see enthusiasm curbed as we desparately need this type of attitude.

Bob

GodBomber!

I agree with you Woodstock(in a non taunting way). I probably won't make them though the idea is still there. I think i would use 4 of thunder tigers .15 or .40 size engines, you know the $50.00 ones. I think they are simple and will be easier to build with what do you think?

ballgunner

My Feedback: (1)

Contrary to popular belief there was a 6 cylinder radial engine made by Curtiss and flown in their Curtiss Robin. At first I didn't believe it but I have seen pictures of the beast. It was actually a twin row with 3 jugs in each row but it still looked like a 6 cylinder radial from the front. Had it been constructed in the conventional manner it would indeed have to have been an uneven number of cylinders such ar 3,5,7 or nine etc. Incidentally from the side the cylinders looked very close together and gave the appearance of a normal radial.

3DFanatic

My Feedback: (5)

Liquid-cooled?? HEAVY.

Jim Messer

My Feedback: (2)

I spent my entire lifetime designing 2-cycle, in-line natural gas engines. They work well up to twelve cylinders. Good balance can be achieved with 4, 6, 8, 10, and 12 cylinders. Odd number cylinders required external balancers, so odd number in-line engines were few and far between.

With V-engines, good balance was achieved with 8, 12, 16, and 20 cylinders. All others required some type of external balancers.

Your 4-cylinder in-line engine will only work, and be balanced O.K. if the crank spacing is 90 degrees apart. You can't fire all four cylinders at the same time, which is what you were thinking. So, that means that all four cylinders would have to be mounted to a single crankcase, with a four throw 90 deg. crankshaft, and with bearings between throws. No problem there, but the big problem that I see is getting fuel into the cylinders. On our big engines we piped natural gas into the cylinders by means of a fuel valve in the cylinder head. For the model engine, each section of the crankcase would need to be sealed from one another to provide crankcase pressure to each individual cylinder, and that, I think, would kill the project.

Your time would be better spend designing a four cylinder flat balanced opposed engine. The design job would be far simpler. Better yet - just go and buy an engine to suit your needs, and save yourself a lot of grief and expense. The end result isn't worth the price of admission.

MinnFlyer

My Feedback: (4)

Please don't misunderstand, I don't mean to be critical. GB sounds a lot like me many years ago. I'm not trying to squash his enthusiasm, I'm simply trying to point it into a direction where it might be put to better use.

When it comes to designing anything, the old adage is: "Form follows Function" And this is a classic case of a Form in search of a Function. Cool? Yes, but why would you use one when there are better options?

Why make a straight-4 when an opposed-4 makes so much more sense? It's shorter, lighter, more evenly balanced, etc., etc., etc.

So what I'm saying is, don't waste that talent and enthusiasm "chasing windmills".**

**Read "Don Quixote" to catch that reference.

PS Good Catch BallGunner, but it was still technically a "Twin Three"

3DFanatic

My Feedback: (5)

Which is pronounced "Donkey Ho-tay" if you didn't know

john flynn

Hey minflier, what's the conection of this topic and A.D.H.D? Please explain. Regards, John.

Balsa Master

who makes that p51 engine there? dont get much more scale than that... anyway, if you have the ability to do mod out some old wngines into this inline-4 then why not? worse comes to worse, sell it, it will be worth more than the 4 heads you used to make it... pluss, i dont see it weighing that much more than the 4 stroke 4 cilinders out there... thing i do see a problem with is the cowling... its going to be like 2X the length of the engine thats suposta fit in there...