different headlights

[Kirk B]

Being new, I'll try to keep the questions interesting. I noticed that the original road car had round headlights. I've seen a couple pics, which I assume are not originals cars, that showed this set up.

I actually like the look, seems more in keeping with the cars of that era. Does anyone know if that front clip is interchangable or if there is a vendor who makes that option?

[Bill D]

The MkI and MkII cars had rectangular headlights. The MkIII street cars had round headlights. The MkIV race cars had round headlights.

You can put anything you want into the area as long as it fits. It may not be authentic, but it's your car.

[Lynn]

The only execept to the spot on explanation that Bill gives is that some of the race cars had round lights down in the marker/turn signal light boxes where many people now put rectangular driving or fog lights. It is generally believed that these round lights were high intensity aircraft landing lights. There has been much speculation as to exactly which aircraft these were from; although, I don't recall what the consensus is. Doing a search on aircraft landing light should bring up some of these discussions.

Regards,
Lynn

[Bill D]

Lynn is correct about the lower hi-powered lights used in racing. I am using 5-3/4" round headlamps but fitted with 130W Halogen bulbs to replicate that style.



Cheers
Bill D

[FRPGUY]

Lynn, If I remember correctly, I thought all aircraft had 24 volt systems.

[Lynn]

FRPGUY, I don't know if that is the case or not (my gut tells me that there is very little chance that a blanket statement like that could be true.) Regardless, I am just reporting what I had come to understand from others. I did not get down and personally inspect any of the cars that used these. If I am not mistaken, it was the JW Automotive group that first used them, so either they found an aircraft with a 12 volt system or determined that the bulbs would work as well with 12 volt as 24 volt (while possible, I doubt that they used transformer coils to up the voltage.) I guess someone could have lied about it, but I have no idea why they would.

Lynn

[Sandy]

You can get the Aircraft sealed beams in 12v and 28v. They are available in PAR 46 sizes as I recall (Look for the long thread). One PAR == .125" so to speak. I have seen PAR 36, PAR 46, PAR 56, PAR 64 lamps, some or all available as aircraft, some just sealed beam.

GE4537 100w is a PAR46. Aircraft landing light 12V was the one that would be my guess as a close fit. They have similar in 28v at 200 w, but not sure how/if the used them (Can't use a transformer on DC, so would have to have had 24v electrics for the lights if they used these). Note that life is short with these bulbs, cost is around $30 for GE, about $10 for off brands as I recall.

Sandy

[jimbo]

I've always wondered about the aircraft landing light story...I don't know why they would have if decent spot beam driving lights were available, which I think they were. The only aircraft part that I am pretty certain was on GT40s was the windshield wiper motor which was reputed to be from a 747, I think. Yes, the voltage was lower, but evidently that put the speed about where it was supposed to be.

On 1149 I used a round set of Cibie spot beams that I got from Aardvark in CA. I also lucked out with a NOS set of Cibie rectangular lamps that are going in the headlamp spaces. The Holy Grail of GT40 lighting is the rectangular Marchals with the "cat face" logo on them- very cool- but I have never seen a set for sale. Although if I haunted Ebay I might...

[Kirk B]

http://www.gt40s.com/gallery/file.php?n=171&w=l
Bill,
Been watching your build, great job! I'll try posting a link or pic (bigger pic of front end is in gallery, pg 6 or 7) of what I'm talking about.... it's 2 round headlights where the rectangle headlight normally is.
I think the whole headlight/fender area is a little different to accomodate both lights.

[BenL]

Originally Posted by jimbo

The only aircraft part that I am pretty certain was on GT40s was the windshield wiper motor which was reputed to be from a 747, I think.

Mostly right. The Mk II (and later?) used the wiper motor from 707s.

[CliffBeer]

Weren't the oil coolers on original cars from a Continental aircraft?? I seem to recall this being the case....

[Chris_K]

Kirk,

The car you're showing is the MK3 version of the GT40. There are some differences between this version and the MKI's and II's.

If I remember correctly, the front fenders (wings) were altered to be longer and higher allowing the mounting of headlights at a legally required min height. The tail section also grew by a significant amount to accomodate a luggage stowage area so it would be able to go touring.

As recently discussed, this version was also center shift (if I remember correctly) but still RHD.

I'm sure there are other differences, but quad lights in the upper buckets on the front were only on the MK3.

Hope that's the answer you were looking for.

Chris

Edit: they also had a bigger "flop-out" panel for their window (the side windows have a 1/4 window and a rectangular portion), and they only made seven MK3's in total (I think- someone please correct me if I'm off). If you're looking for a proper representation of a 40, you'd be better off with the large rectangular lamps. On the other hand, if you like the quad set-up, I say go for it!

[FRPGUY]

After talking to an Airline pilot friend and another friend who owns an FBO ( fixed base operator ) and is an I.A., I've been told that the 707 had 108 volt system and most General Aviation aircraft have 24/28 volt systems. On General Av. aircraft the alt. charges to 28 volts. My airline pilot friend said that the 707 elect. system was dangerous and everything had warning placards stuck everywhere.
Between the two guys, they couldn't figure out how the landing lights and 707 windshield wiper would work set up in a race car back in the sixties. Anyone know?

[John W]

Bill,
I have no idea where 108 volts is used on the aircraft, but it is not for any of the instrumentation.

I have a 707 wiper in my hand here, and can confirm it says it is a 24 volt part.

My day job currently has me designing kit that is fitted into light aircraft, and all the systems are 24 to 28 volts.
Previous jobs have included in filight entertainment systems for major Airlines, all of which were run from 28 volts too.

The 707 wiper motor is run from 12 volts without any wiring modifications in the mkIIs and mkIVs. This simply makes it run at a slower speed.
The motor is a 2 speed type, controlled by connecting one of two wires to earth through different value ballast resistors. The third connection is to the positive supply (well that's the way it is in the aircraft anyway).
Hope that helps

[FRPGUY]

John, Thanks for answering a question I've had since the late sixties. I figure, if I live long enough, I'll hopefully have all the mystery of the GT40 solved. Based on what you said about the wiper motor running slower; will the landing lights be dimmer? The load on the electrical system must have been quite high with the wiper on and any aircraft landing lights on.
I'll have my airline friend check his check list again ! I'm only a Private Pilot and not really up on 707 systems.
I guess the MKII wiper motors worked OK in 1966 !

[Lynn]

FRPGUY

FYI Last I heard, Lee Holman was paying around $1400 per for the 707 wiper motors to an aircraft graveyard somewhere in AZ, I believe.

Lynn

[Sandy]

Originally Posted by FRPGUY

... Based on what you said about the wiper motor running slower; will the landing lights be dimmer? The load on the electrical system must have been quite high with the wiper on and any aircraft landing lights on.

They used likely use the 12volt lights, at 100w, that is about 8 amps each bulb. The wiper likely used about half of the current since it was running on 12 volts (run slower too). If you did run the 28v lights likely would be dim and still draw about the same current as the 12v version (I think the 28v version were 200watt bulbs). They might have had 200w 12v bulbs but not someting that I have seen.

Sandy

[Clayton]

FRPGUY
Some of the early GA aircraft (bug smashes) were 12vdc but most are 28vdc, as they get larger (airliners) they tend to run 28vdc and 115vac / 400 Hz in the same airframe.
Taxi lights can get up to 450w’s and landing lights up to 1000w’s (28vdc).
Hope this helps

Clayton

[FRPGUY]

Thanks for the info guys.
Thanks Clayton! My airline friend relayed the same info to me this morning over coffee.
and $ 1400.00 for a 707 windshield wiper... it is what it is I guess