Graham's RCR GT40 Build...

[Randy V]

Nice workmanship Graham....

The NACA ducts are a particular problem for me and I've been spending quite a bit of time with them lately. Not so much the contour of the opening, but what to do when them.
I've set about creating all the duct-work underneath the front clip so that I can bring that air to the passenger cabin.

I really like the contour you gave the openings.. I'll strive for similar results on my own.. One thing I noticed on my front clip is that the shape of the top of the fenders on each side is different, so the NACA duct's "roof" is different on each. It looks like you've straightened yours out.. :thumbsup:

 

[Graham]

Randy,

The shape has been arrived at more by neccesity than design in some ways...

When filling, sanding, filling etc, it seems to be easier with the limited access to give them more of a rounded contour (which I kind of like). I have the opposite problem to you though... What to do with them from inside the clip. I'm tempted to route them into the cabin for fresh air (I have formed a 4" cavity internally), but the weather here is rarely (if ever) as nice as where you are, so I may get through the IVA over here and then decide.

BTW, I liked your solution for the clip hinging. NOT something I could make myself though :embarassed:

Cheers,

Graham.

 

[Graham]

Nice workmanship Graham....

One thing I noticed on my front clip is that the shape of the top of the fenders on each side is different, so the NACA duct's "roof" is different on each. It looks like you've straightened yours out.. :thumbsup:

Can you elucidate on this? I may need to head to my garage to have a look at mine...

Cheers,

Graham.

 

[Graham]

Randy,

By far the biggest pain has been the large NACA duct in the cente by the windscreen. I cut out the original and then glassed it in to meet the rear of the clip. It's only set back around an inch, but it does give more depth and "realism" to the opening".

Filling and sanding this is a HUGE PITA as there is NO room to move with sanding...

Not finished yet, but gives you an idea of where its heading. I may ultimately cut the base of it out at the back, and for a watertight opening into the cockpit, but again, that may or may not happen after the IVA.

Cheers,

Graham.

 

[Randy V]

Can you elucidate on this? I may need to head to my garage to have a look at mine...

Cheers,

Graham.

It's actually rather difficult to see unless you look at it at the right angle -
There is more curvature from the top of the fender on the one side than the other and that increases the height of the NACA duct opening on the outside of the hole vs. the inside when comparing the two ducts..

Don't know if I'm making any sense at all in that... :huh:

Also - There is a gap to fill between the back of the NACA duct and the bulkhead.. I'm not sure what I'll be filling that with yet.. Probably a bit of kitty-hair followed by 3M-HSRF.

I've been updating my website periodically and added a section on the Air Ducts.. I nabbed part of this idea from Eglitom (thanks Tom!) - but my execution is not nearly as nice as his.. Still a bit of work to do to smoothen it out, but the whol bottom side of the clip (around the wheels) will be done with Pickup truck Bedliner material that will be really tough..

http://www.gt-forty.com/GT-Forty/Front-Clip/Pages/Air_Ducts.html

Center duct - I have a plan there as well since it must have SOME function (I hate fake things - even on Replicas)...

 

[Fran Hall RCR]

Graham.....

nice work but with all the rain in the UK...I would suggest a water trap somehwere along the air tube and maybe a sliding panel behind the larger NACA duct to keep out the weather but also make the AC more effective...
The fewer air/water leaks the better for an more effective AC system ..

 

[Graham]

Fran,

Surely you jest, the weather here is BOOOODIFUL all the time....NOT!
The thought had crossed my mind re a water trap, so thanks for the heads up :thumbsup:

Randy,

Heres a couple of piccies of my ducts from front on. There is a slight difference between the two. The left hand certainly seems on a slightly higher angle. I'll put it down to being a one off, individual car (which you may end up doing too ). Hope it helps.

Graham.

 

[Dalton Veitch]

Graham,

I've seen a DRB here where the owner uses the car for long interstate trips, so wanted to introduce some fresh air to the interior without opening a window flap. He extended an air passage from the centre duct to the interior. The opening down from the central intake into the behind dash area is relatively small, and has a cable operated horizontal slide valve so it can be open or closed. This drops the air into a horizontal left to right "trough"from whence it just blows into the under-dashboard area. The trough has ends and a drain pipe to handle the water that blows in. The fresh air just blows up over the sides/ends. Just a thought.

 

[Graham]

Graham,

I've seen a DRB here where the owner uses the car for long interstate trips, so wanted to introduce some fresh air to the interior without opening a window flap. He extended an air passage from the centre duct to the interior. The opening down from the central intake into the behind dash area is relatively small, and has a cable operated horizontal slide valve so it can be open or closed. This drops the air into a horizontal left to right "trough"from whence it just blows into the under-dashboard area. The trough has ends and a drain pipe to handle the water that blows in. The fresh air just blows up over the sides/ends. Just a thought.

Thanks for that. That's the kind of thing that I was ruminating over. It's a way off yet though, I still have a list of 4367 things to do first

Graham.

 

[Ian Anderson]

Graham

Don't forget you will have to radius all the edges to get through IVA

Simple way is
Head down to B&Q and get a cistern ball float
Roll it over the surface
Whatever that can contact will need a radius to it of the stated size

Cheers
Ian

 

[Chuck]

Fran,

Heres a couple of piccies of my ducts from front on. There is a slight difference between the two. The left hand certainly seems on a slightly higher angle. I'll put it down to being a one off, individual car (which you may end up doing too ). Hope it helps.

Graham.

At Road America, 2009, when Ford celebrated the GT40, I had a chance to really study a dozen or so original GT40s, sometimes parked right next to a reproduction. The variation you have noticed in the vent openings is exactly what can be seen on some originals. It is amazing how few even notice that detail. Indeed some of the reproductions, with their perfect left to right symmetry, look less original than does your RCR for that very reason. My clip is the same as yours. That is an authentic detail, not a defect.

I am not going to name brands, but can tell you that having had the opportunity to compare five different reproductions next to original GTs the RCR was the one that would be most difficult to distinguish from the original.

 

[Randy V]

Thanks for posting the pics and information Graham...

Chuck / Guys - I did not mean to infer that my clip was different from the originals.. Indeed they are the same from what I also have observed in looking at many pictures.

I've opted to not try and replicate to the "T" the Original, but to make improvements where I can and add in creature comforts, etc..

Still - I don't like anything that's phoney - so that is a prime directive I am on..

 

[Graham]

Graham

Don't forget you will have to radius all the edges to get through IVA

Simple way is
Head down to B&Q and get a cistern ball float
Roll it over the surface
Whatever that can contact will need a radius to it of the stated size

Cheers
Ian

Ian,

Don't want to seem thick (which I probably am), but what do you mean by this?

Cheers pal,

Graham.

 

[Brett James-McCall]

Graham,
He means the radius test that IVA requires, though the projection has to be more than 1.5mm. Its section 16 in the IVA manual.

Here's a snippet:

​

All ‘hard’ parts contactable with a 100mm sphere, which form an external surface or protrude 5mm or more from the external surface must have a radius of curvature of at least 2.5mm (see note 2).

The criteria of Standard 2 DOES NOT apply to the following, which must be checked to their individual requirements:​

3. Protrusions less than 5mm but more than 1.5mm contactable with a 100mm sphere must have blunted edges.

 

[Ian Anderson]

Correct Brett

At my SVA the "Mini Hitler" tested all the naca ducts with the ball and ran the redius tester over them

Ian

 

[EGLITOM]

Graham
This is what i did

http://www.gt40s.com/forum/gt40-build-logs/24525-toms-rcr-40-trackracer-10.html#post246375

you also can see the water trap i built (not finished in that pic, but you get the idea)

Randy

to cover the gap between the buklhead and the opened NACA duct. I used this thick PP foil, sticked it all the way through the opened NACA duct to create a mould and covered it with glass from the front and backside of the bulkhead(picture just showing the glassing from the backside sorry)

TOM

 

[Randy V]

Thanks Tom - Im going over your Build Log front-to-back ((again))

Here is what my fresh air ducts look like at this point;

More here;
GT-Forty.com

 

[Graham]

Thanks Tom - Im going over your Build Log front-to-back ((again))

Here is what my fresh air ducts look like at this point;

More here;
GT-Forty.com

Randy, just spotted these on my thread. Did you form them out of fibreglass matting around a shaped piece of polystyrene?
I would be interested to know the process. Looks great!

Graham.

 

[Randy V]

Hi Graham,

You can find the whole story on my website (if the host will leave the site online - billing problems);

GT-Forty.com

I actually made them from flat fiberglass stock that I hot-glued together and then roughed them up and used Epoxy-Resin and Fiberglass to pull the whole nine-yards together.. one layer of mat and one layer of cloth with a little extra cloth where the ducts meet the body..
The Transfer ducts (triangular pieces) I made from very light-weight aluminum that were patterned from cardboard.. Again hot-glued, roughed up and buried in Fiberglass..


Let me know if you have any questions..

 

[David]

At my SVA the "Mini Hitler" tested all the naca ducts with the ball and ran the redius tester over them

Ouch

Not sure how well they really work as a proper NACA duct without sharp edges which would probably fail IVA/SVA. I suppose it answers my question as to if I bother to make mine functional pre-IVA/SVA.