Radial Engine Test Backfires (actually it's an afterfire)

this is how you know your engine is 180 out of time. more video of the event here:
http://www.youtube.com/watch?v=NnLfoPcY-9Y

make sure you check that it is on the compression stroke before setting the timing, the exhaust stroke doesn't work so well...

we got it to run great after this discovery.

engine is a P&W r-985 wasp jr. It was fun learning how a radial engine works.

Category:

Autos & Vehicles

Tags:

• radial
• aircraft
• engine
• test
• backfire
• powerplant
• mechanic
• school
• a&p

[lsrengines]

Is this the SCC student program?

[anoblenate]

why yes it is!

[slainwolf180]

i wonder how the oil gets in or out of the engine? does it sit in the bottom of the pistons below?

[anoblenate]

The little green tank right behind the engine on top of the mounting frame holds the oil it gets pumped down into the engine where it circulates throughout the lubrication system. if left to sit for long periods of time the oil will pool in the bottom cylinders and has to be drained through a spark plug hole before turning the prop.

[saddamsalaugh]

whats it attached to .. Joe 90s car

[anoblenate]

haha. well, its part of an old heli attached to a frame for a test stand built long ago. we could mount a few different engines on to it after overhaul for testing.

[kirkmach32]

BOMMMF

STOP

LOLOLOL

[tpvalley]

Generally they call a bang from exhaust on the "back" of a vehicle a "back-fire".

They generally call carb fire a "spitback" or a "aaaaaaarrrrrggghhhhh I'm on fire.".  :-)

[hammerogod]

When you are standing near one of these adorable monsters with a Fire Extinguisher and they do that you get an Oil Bath.

The damned things can throw oil 100 ft.

Always a thrill.

[BlackWiiOwner2010]

The big backfire was boom-tastic. Why did it backfire like that? Does this engine have blow plugs in the lower cylinders to prevent hydro-lock?

[wheelieguy]

When I went to school here (it was Somerset Vocational Technical School then) taking Auto Body Repair, they had an old DC-3 sitting behind the storage/maintenance shed and what was then the machine tool technology shop. About once every year or two, they would start that bad boy up. It was loud, smokey, and smelly, but man it was so sweet to hear that thing fire up! They finally fixed it up and flew it out of there several years ago. I got in it and walked around once. It was a cool plane!

[unbornduckman]

Actually it's a forward fire cause it's going forward threw the system out tje exhaust the back fire is coming out the intake side backward threw the system

[badbrains409]

helluva test cell you got goin on there....

[67tr876]

get a new one LOL

[connell256]

epic lol

[BamaRailfan]

Actually I think that definition applies universally, but is often misquoted...