The things that go unoticed...

[Eric Ahlstrom]

It occurs to me as I explain to the 150th (maybe more...) interested person that many of the things I consider obvious have gone unnoticed for decades.

I am speaking specifically of the oil streak data I see on every aircraft I look at and what it means to me. If coventional wisdom were to be true, the oil streaks that are present on every Unlimited and warbird in the world (they all leak) would not exist.

Look at the oil.

Ask questions.

Does what you see agree with what you have been told???

I'll give you a hint here: it doesn't. My question is, since it doesn't we are stuck with three possiblities...

1. What we have been told (right or wrong) is more important than what we see.

2. What we see is not reality and the people who have told us how air flows know things that we will never understand.

3. What we see IS reality and the people telling us things that contradict that reality don't know what they are talking about.

Good luck on the quiz...

[Scotty G]

Oil?

So... What you're saying is that these planes shouldn't be leaking any oil..?



Scotty G

[THE DOCTOR]

GEE ERIC, ITS KIND OF LIKE READING TEA LEAVES ISN'T IT ?

OR IS THAT WINE STAINS.

SERIOUSLY IT WAS THE OIL STREAK DATA THAT DROVE THE POINT

HOME ON THE STREGA CUSTOM COWL SOME YEARA BACK.

WHAT A BATTLE ROYAL THAT WAS!

THE DOC

[AAFO_WSagar]

Hi Doc,

I don't know if guys really protect their secret "$hit" that closely, but I even know of one team that told me they absolutely cleaned their streaks as fast as possible so nobody could see how well what they'd done worked..

Kind of like built in tuft test ey

Wayne
PS.. Anybody find any magic brew for Tige so he can make it this year? Dunno how he could sit this one out...

[John]

I'm Thinking...

...the pressure inside the cowling is to great, thereby blowing
the oil out. Of course you need some pressure in there to help
cool the thing, probably more than you need to eliminte the drag.

[Keith Doyne]

There is no questiuon about airplanes leak oil. This lost oil should follow the flow of air over the surface of the aircraft. To someone with Eric's expertise, this oil data can tell him alot about the aerodynmaics of the aircraft. I bet he can tell if an improvement (i.e. "secret sh*t") works or does not, or he can tell what improvements might be needed. I remember seeing a photo of Daryl Greenamyer's bearcat at RENO, just after breaking the speed record. The photo was in John Tegler's book, and the photo caption noted the exhaust/oil streak on the side of the airplane. This streak clearly show the flow of air over the fuselage, after of the exhaust stack. As Wayne put it, a built in tuft test.

For Eric & the Doctor, they have CLEARLY proven they read the "tea leaves"!!!

Keith Doyne

[Eric Ahlstrom]

Reading the tea leaves...

Originally posted by THE DOCTOR
GEE ERIC, ITS KIND OF LIKE READING TEA LEAVES ISN'T IT ?

OR IS THAT WINE STAINS.

SERIOUSLY IT WAS THE OIL STREAK DATA THAT DROVE THE POINT

HOME ON THE STREGA CUSTOM COWL SOME YEARA BACK.

WHAT A BATTLE ROYAL THAT WAS!

THE DOC

I would love to hear about the battle and the assumptions (no names) that were bounced around and how the streaks settled the issues. I have been amazed at the ratio of physical experimentation (building parts and trying stuff) vs. taking anything other than lap times as data. Does anyone tuft? Take pictures of their oil streaks? Plan tests? Record anything?????

Other than lap times and engine data, I haven't seen much. What aero data is available when I start asking questions is all anecdotal, while the dissertation and record keeping of engine data by some teams would do an Indy car team proud.