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

[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

[lsrengines]

Is this the SCC student program?

[anoblenate]

why yes it is!

[rickyguerra4]

Actually in aviation terms that was an after fire. A back fire is the result of the flame propagating through the intake manifold and back out out the carburetor.

[BamaRailfan]

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

[gescoboza]

hahahah it farted !

[cummins60]

that motor is junk now

[duanedragon2]

I had one just like that in high school, only mine was an inline 4 cylinder and looked more like a Pinto.

[ejlister]

ROFLMAO!

[kirkmach32]

BOMMMF

STOP

LOLOLOL

[Logitech1604]

WTF is that WOW cool nice job ^^

[rotienamenam]

sorry, but aren`t this supposed to be called afterfire coz the name applies to the direction of the flow. so, from carburator to exhaust it`s called afterfire. backfire is when the fire came out through the carburator from the comb chamber. correct me if i`m wrong.

[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.". :-)

[GedMpBasS]

Thats the most general assumption, and its partially right. However, technically, a "backfire" is when the intake and exhaust valve is open on the compression stroke sending the fuel/air mix. "back" into the carburator via intake valve. An "afterfire" is indeed the explosion you hear and may see from the exhaust pipe. "Spitback" is a good way of saying it in greasemonkey slang. :)

[tpvalley]

The intake and exhaust r never both open at same time on compression stroke, they overlap on the top of exhaust stroke/ beginning of inlet stroke.

After compression stroke, u have power stroke, near end of power stroke exhaust valve opens, then exhaust stroke, inlet opening during end of exhaust, exhaust valve closing during beginning of intake stroke, and so on.

Flame is carried through several strokes when it doesn't fire properly, charge can collect and ignite in exhaust or inlet manifolds

[GedMpBasS]

I know how a 4-stroke engine works, no need to explain, however, don't you think that old or engine who's push rods have not been timed properly may experience the intake valve closing too late?

[tpvalley]

it would have to beover 180 degrees out!

I think ( although none of us know for sure) spitback and backfire r a result of a missfire where the vapour/charge ignites late in cylinder,the flame kind of hangs around or gets blown out of exhaust etc, even still being lit when inlet opens.

I have noticed wrong timing makes spit backs occur, but the inlet spit is a bit of a mystery.

[caprimentle]

it does say at the top 180 degrees out so you would most likey be correct with that idea.

[tpvalley]

Good grief, cant believe I didnt see that!

DOH!!

I guess other folk make same mistake!!

Again doh!

And thanks!

How come it fired though?

[caprimentle]

good question haha, as its push rods i assume only a couple of the cylinders had there valve timing wrong and some didn't, i wouldn't know though to be honest.

[PecuniaLuxMea]

so cute ~_~

[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.

[slainwolf180]

Thanks but is it a total loss system? i never figured out where the oil pickup might be

[huettmr]

Un pedo

[violented16]

booman606 you are 99% right, Up here in northern Canada we have a guy that fly's DC3's and DC4's as regular schedule flights. Its pretty neat seeing him fire up the old DC3 every morning and warm it up. If you care to know the company its Buffalo Airways, im sure they must have a site somewhere on the net.

[booman606]

oh A&P school is so fun. making mistakes is part of the learning experience. unfortunately the only place you get radial experience is there. everything is turbines these days. if you get to start a radial with an inertia type starter, its freakin' sweet.

[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.

[mustangpapi76]

Ha ha.... i just ran that engine at school like a month agoat Spartan collage of aeronautics in Tulsa Ok. that beast is alsome when you riche up the carb on it and watch the exaust flame. judginging by the after fire from the exaust on start up, it might have been over primed or you forfog to turn the primmer to lock it into place. that wuld be the first thing i would have checked. hey i'm still learnning.

[dhutch2000]

Last time i did that was a honda C90 bike engine (in a kart) - And that was equally good at starting.

[youngmarines5]

dude im goin to be an engine mechanic after high school and im scared already that im goin to mess up casue if i mess up the airplane can blow up or something but im goin to do my best

[mustangpapi76]

dude.. don't worry about it too much. they make everything in school and in the fleet MARINE PROOF. you have a blast at it. the cool thing about aviaiton school in the Marines, thats its in Florida but its a year long. loved them beaches. HA HA!!

[avitech77]

I am training to become an A&P mechanic in California.  I am so scared of making mistakes. Peoples lives depend on it and all.

[froppo]

Coolness! You should video the working product...that is if you're still working on it...if that makes any sense. :)