When did belled holes spread from aircraft to race car construction?

When did American race car builders first start using belling dies to strengthen flat panels? Post-war?

 

Who ever said drilled holes spread from aircraft to race car construction? Probably was the other way around!

 

Its not that they are drilled, they are belled. See how the hole is flared? This is generally done using a belling die, although it can be done on thin material with a slotted stick, or smooth-faced pliers with a curved jaw. The earliest photos of belled holes I have seen are in WWII aircraft monocoques, I have not seen them in American built race cars prior to that. If you have photos of belled holes in american built race cars prior to WWII, or any other documentation supporting that, post away. That is exactly what I am trying to find out.

 

Growing up in the fifties I recall the interlocking landing strip material , probably left over as WW2 surplus being used extensivly as car hauler decks and ramps .... and the occasional flared holes on the "A" visors . They were around but other than drilled straight axles, not many "holes" were done as I recall ..... louvers were a different thing though.

 

Thanks Sam, yes, I dont see much of it in hot rods in the fifties either. Thats why I asked. I was thinking it may have been used in indy car construction in the fifties, but I dont have any photographic evidence to support that. I will have to take a look at photos of some of the more sophisticated Bonneville cars from the period as well.
Guys would have been exposed to the use of belling dies in WWII, I am guessing that the technique would have spread post war, just trying to establish that.

Now you have sent me off on another tangent, trying to remember what they called that interlocking temporary landing strip material...

 

they may be older than you think... I believe the supermarine s.6 schneider trophy racer may have had them in the late 20's as it was an all metal monoplane that was riddled with holes.

 

The earliest automobile use that I remember is the 1960 Lotus 18. Chapman was a firm believer in using aircraft building techniques.

 

I was actually thinking of that aircraft, as I believe that was the first use of them in aircraft construction, and pioneered metal monocoque aircraft construction that became the rule in WWII. But that plane was real cutting edge stuff when it appeared.

early sixties is supported by most of what I have seen so far, but my guts tell me they were probably used in race cars earlier than that. Started thinking about this last night, just curious to see what comes out of this thread. I will do some further digging myself, and see what I can find. Keep it coming guys.

 

I don't know the history of them, but there big in the off road world
I'm having dies made right now by a local machine shop for just this purpose.

 

that's one hell of an understatement! that thing had 1900hp in the late 20's. it used surface cooling along the fuselage, wings and even in the floats to keep the engine cool without adding drag! nevermind the crazy aluminum monocoque!

 

I am not race car historian but I do have a few issues of Honk! and Hop Up from the early 1950s that delve into Indy car construction and none of them show any flared holes like that. (And these were cutting-edge cars at the time.)

You could probably contact the museum at Indianapolis and ask them? They have cars there from every single year it's been run, mostly the winners.

 

Not good enough shots to say for sure, but judging by the discription and pic, it doesn't appear Kurtis used that method on Vuky's Indy car.

 

Thanks guys. This confirms what I have found so far, if anyone was doing it, I would think it would have been Kurtis. Kind of surprising, as there were so many other things that transfered over from aircraft construction post-war. They were pretty much de-riguer in indy car construction Indy cars by the mid-sixties, I guess this is just one more thing we can add to the list of things that were copied from Colin Chapman.

 

I know that most of the airships used that method of construction in the 1920's on up. I haven't found any photos of that method of construction in the WWI era Zeppelins, but I would think that they would have used similar methods of construction. Here is a picture of Hugo Eckener in the Graf Zeppelin in the late 1920's.
The other picture is of the frame of a 1935 Chevrolet. I have also seen these holes in limited use in 1920's fire trucks that I have worked on. I just don't have any pictures....

 

When you think about it, the mid sixties when Monocoque construction became the norm would almost have to be the beginings of this practice. I have a book that shows lots of Kurtis cars from the roadster era under construction with lots of holes, but none flaired that I see. With the light, rear engined sheet metal "frame" construction the belled hole would have added a lot of strength that would have used stronger plate otherwise.

 

Here is one that predates even aircraft. The 1904 Premier Vanderbilt Cup racer. They used tons of holes in it, but they aren't belled.

 

I think it was Dennis Jenkinson that said "There is nothing lighter than a hole". Light weight is vital to planes and fast cars. Which came first could be debated forever.

 

falcongeorge, the landing strip material was called PSP (pierced steel plank). Still see lots of it around on trailers, etc.

 

Isn't there a row of belled holes in the rear inner panel on a 32 3w coupe? I'm not totally sure that there is but if i'm thinking correctly then that predates WW2.

Chris

 

Yea, thats it! Saves me looking it up when i get home from work!

 

Yea, never thought of that.

never owned a 3 window. Anybody confirm this?

 

For sure, its a key element of building monocoque cars, but it offers the same benefits in a tube chassis car, in that you can build a bracket with the same rigidity out of lighter gauge material. Thats why I was surprised to not find evidence of it in the construction shots I looked at of fifties indy cars and midgets. The tooling was well within thier means, and by that time, the influence of WWII aircraft construction practices were fairly widespread in race car construction, so why are belled lightening holes so conspiciously absent? I will do a little more research over the next couple days, but if Frank Kurtis wasn't doing it??? Maybe its Miller time. I'll break out a couple books when I get home, see if I can see anything there.

 

Hold on a minute. Dont know what year this is, but this is a shot of the Kurtis shop. Looks to be mid-fifties? Look at the inside of the frame rail on the car in the foreground.

 

The logical conclusion to this thread.

 

Ya recon' this thing possibly made some weird "whistling" noises at speed? DD

 

Holes, yes, plenty. Belled, no.

Look at some of the pre-war German racecars. Or Italian or other European. I'd bet the big guys did it before smaller shops like Kurtis.

 

I would think you are probably right. I missed the Zepplin connection that another guy pointed out. I was thinking that it started with the Schnieder trophy racer, and would have trickled down to american race car building, and possibly some of the more sophisticated hot rod builders post-war, as guys that had worked on aircraft during the war started building hot rods and race cars. The mid thirties chevy chassis was interesting, and the photo I found points to Kurtis doing it sometime in the mid-late fifties. Its turning out to be a pretty interesting thread.

And yes, the famous five-window is irrelevant to this thread.

 

Here is a close shot of the hemi powered Indy roadster. Not flared.

 

A somewhat less than scientific way to date that photo:

The post war midgets in the background, some work on those cars started apparently in late 1945. The car in the foreground is I believe the car that Frank rebuilt for Ed Walsh and which appeared at "The Speedway" in '46 and '47. So I think we can say that the photo was taken prior to Memorial day 1946.