Engine balancing
Just to show how far behind we arein technology. Was looking through an old AVIATION MECHANICS SIMPLIFIED book copyright 1943 shows a Wright Cyclone 14 cyl with floating counterweights to "smooth out firing impulses" Where have we been? Any old aeromechanics care to comment?

Hi Gord, I've read your post and I don't have a clue what you are talking about. What were the counter weights floating in? Were they just slinging round and round? Do they have any relavance to modern day giant R/C engines? Please enlighten us.

It has always amazed me at the engineering and manufacturing that brought the massive aircraft industry into full production in such a short time to produce aircraft to support the WWII effort. We must never forget the highly intellegent people who did this.

Ken

Almost all automobile engines that have and inline cyl arrangement have a balance shaft in them to take care of the harmonics created at certain rpms.

On radial airplane engines, he is talking about a balance ring in the engine crankcase. It works like the balance shaft in the auto engines.

Jim

w8ye the principle is the same. All engines have some means of counterbalancing the rotating weight of the rod journal, rod and part of the piston. This consists of a weight attached to an extension of the crankwebs.Thedynamic damper is similar to this but the weights are not rigidly fastened to the webs. They can move slightly, and are designed so that they can oscillate between ignition impulses and accelerations and decellerations of the crank and cancel out the fluctuations.I believe it would make a bigger difference on a single cyl engine. I should try it on an old Quadra 35 .Just have to figure out how to make an instrument to measure engine vibration to get a comparison.

Fly paper, there is nothing wrong about what you said. Everything is right on.

But the original point was about floating (counterweights) on a radial Wright R2600 airplane engine. They were actually a balance ring simular to the balance shaft in the modern day auto engines. I have several Dodge cars and they all have two shafts down in the oil pan that are driven off the crankshaft that are used to dampen hormonics at certain rpms. The shafts resemble camshafts but they don't do anything but spin. There is actually nothing that floats on them. They just turn at a different rpm than the crankshaft to cancel hormonics. These Dodge engines have no harmonic balancer on the nose of the crankshaft. I know about the fluid filled and also the rubber mounted harmonic balancers that people buy for their hot rod chevys and fords but this is a slightly different principle.

Enjoy,

Jim

Years ago there was a ring balancer sold for auto wheels.. It was a circular tube partly filled with a liquid and ball bearings..the weight of the balls was supposed to go to the unbalanced side..Don't know if it worked, haven't seen them for years..We had a small, about 4 inches around, steel ring filled with mercury, that was bolted to the crank on top of the prop, to do the same thing..It didn't seem to make any difference....

If I ever figure out how to get my copier to work on the internet I'd send you a picture. It.s like if you were to cut off the counterweight, drill 2holes in it side by side and put pins in it somewhat like wristpins. Drill 2 holes about twice the size of the pins in the crank and mount the weight back on the crank with the pins in these 2 holes sothe pins float in the oversize holes. Sorry I'm not very good at explaining things. Now to work on my copier!!

Seems like that would take care of accerating and decelerating dynamic hormonic vibrations?

Jim

Also it should work at all rpm. At high rpm with high centrifugal force it would not oscillate very far, vice versa at low rpm which is what you would want.