Super Corsair

[Reever]

Re: Super Corsair

That takeoff shot really showed how slick the canopy was compared to the stock version. Great shot!

[Leo]

Re: Super Corsair

"V-12's are internally lubricated engines, while Redial engines are externally lubricated "

And like anything British, if it isn't leaking oil, it must be empty.

[toldjaso]

Re: Super Corsair

Leo: just curious, any idea why are the 4360's such "smoke bombs"? Simply more cylinders than the 3350's or 2800's? Higher compression? Having seen the startups of Dread, Furias and various super Corsairs over the years, I've always wondered....

One issue with Rare Bear and the rest of these air racers is the fact that most of these 3350's and the 4360's usually came off of tricycle-gear airplanes. The engines normally sat fairly level. When you put one of these engines on the nose of a tail-wheel type airplane, it tilts the front of the engine several degrees up, when it is just sitting there parked on the ground. The oil that runs past the piston rings and through the valve guides and fills the rocker boxes on all cylinders that are below 3 and 9 o'clock on the engine either fills the combustion chamber, or runs out past the exhaust valve if it is open, or runs back into the intake pipe, if the intake valve is open. This can cause a liquid lock, and bend or break a rod on startup. Just removing the lower spark plugs is not a guarantee this will not happen, if the intake tube has a pool of oil sitting in it (such as on a tail wheel type airplane).
Some engines had small oil collection boxes in between the lower cylinders, with lines or hoses hooked from rocker boxes or intake pipes or both, that delivered the oil back to the oil sump on startup. Most racers don't have these installed on them, as they are a real pain to remove and re-install, add weight and complexity, and are another potential fail point that could cause an oil leak.
The starters have a clutch setup that is supposed to slip if you have a hydraulic lock when cranking the engine, it slips and won't crank the engine. Nobody with any sanity really believes that is a safe bet, or that it really prevents engine damage if you try to crank it and it has a hydraulic lock. Kind of a last resort type design.
So yeah, the more cylinders you have hanging down, and the looser your engine tolerances, the more smoke you get. Sometimes the end gaps on the piston rings all line up, that really makes a for a leaker.
We used to add oil to the DC-3's from 5 gallon buckets, or a 55 gallon drum with a pump on the forklift.

[Leo]

Re: Super Corsair

Also the reason you see them pulling the props through on the big radials.

[toldjaso]

Re: Super Corsair

Also the reason you see them pulling the props through on the big radials.

Even pulling them through can do damage, if the person pulling (pushing) the prop through moves too fast, or with too much force, you can actually bend a link rod or push it through compression, and still have a cylinder on the brink of a liquid lock, especially right after startup.
Pratt and Whitney's recommendation was to remove the spark plugs from the lower cylinders, start and run the engine for two minutes, then shutdown and re-install the plugs just before startup, if you suspect a liquid lock, or if the plane has sat for a long period of time, etc.

[FlyKidChris]

Re: Super Corsair

Did they ever come up with an idea of what let go, leading to the crash?

The NTSB accident report states that the engine was too destroyed to determine the cause of the failure. However, I believe most suspected a failure of one of the master rods (master connecting rod).

The NTSB identifier for the accident report is LAX94LA168 if you'd like to do more research.

[ChrisMX105]

Re: Super Corsair

Even pulling them through can do damage, if the person pulling (pushing) the prop through moves too fast, or with too much force, you can actually bend a link rod or push it through compression, and still have a cylinder on the brink of a liquid lock, especially right after startup.
Pratt and Whitney's recommendation was to remove the spark plugs from the lower cylinders, start and run the engine for two minutes, then shutdown and re-install the plugs just before startup, if you suspect a liquid lock, or if the plane has sat for a long period of time, etc.

And one of the worst things to do is pull the prop through backwards as it shoves any oil in the cylinders back into an intake tube where it sits waiting to warm up and fill a cylinder on a running engine.

On RB it was standard process to reduce the chance as much as possible by pulling the bottom rear plugs ASAP after a run or flight. The guys dancing under the enjoy are doing so to dodge hot oil not out of joy............

And Toldjaso is 100% correct, figure the torque put out by a 200lb guy hangin on the end of a 6ft blade..................

[wingman]

Re: Super Corsair

[Leo]

Re: Super Corsair

Ooooh Neil!
Airplane porn!

[440_Magnum]

Re: Super Corsair

And it sure did SMOKE!
All the 4360's do.

Some more than others... (see: Furias in its early days). :-)

[440_Magnum]

Re: Super Corsair

The starters have a clutch setup that is supposed to slip if you have a hydraulic lock when cranking the engine, it slips and won't crank the engine. Nobody with any sanity really believes that is a safe bet, or that it really prevents engine damage if you try to crank it and it has a hydraulic lock. Kind of a last resort type design.

One big problem I see with that is the angular momentum of a 14-foot-plus diameter 4-blade prop that is already rotating. Sure, the starter clutch might slip at a low enough torque to save a rod from bending, but the momentum of the prop doesn't give a rat's backside about what that starter clutch is doing.

[88SC]

Re: Super Corsair

I'd like to have experienced standing near the wingtip in the run up shot. Even with sufficient ear protection, you'd still feel the power blasting thru your body. Might have to stand back a bit for your diaphragm to function...

[wingman]

Re: Super Corsair

Before you get too excited about the idea, it's worth noting that that kind of sh*t (along with a lot of firearms) is why I have eternal Tinnitis. My ears ring a bit all the time...

Neal

[supercub]

Re: Super Corsair

Did the Super Corsair have the potential of being a 500mph plus airplane on the course...........or perhaps going after the 3km speed record held by the Bear?

[Rarebearcat]

Re: Super Corsair

Before you get too excited about the idea, it's worth noting that that kind of sh*t (along with a lot of firearms) is why I have eternal Tinnitis. My ears ring a bit all the time...

Neal

Yes, loud engines and big guns have done a number on my ears also. As a kid, I flew all over the country in the backseat of a Bonanza without headsets. I'm sure that didn't help any.