Author Topic: NACA 66 Special A/BGS  (Read 596496 times)

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Offline robfrey

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Re: NACA 66 Special A/BGS
« Reply #390 on: August 12, 2012, 09:15:51 PM »
Eric has been making great strides with the body. Eric has requested that I don't post any pictures of the progress until we are all done.
That way he can post the progression from start to finish within a couple of post.
We plan on fitting the body to the chassis in October.
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Offline SPARKY

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Re: NACA 66 Special A/BGS
« Reply #391 on: August 14, 2012, 09:05:42 AM »
Whooe exciting times in LSR
Miss LIBERTY,  changing T.K.I.  to noise, dust, rust, BLUE HATS & hopefully not scrap!!

"Security is mostly a superstition. It does not exist in nature, nor do the children of men as a whole experience it. Avoiding danger is no safer in the long run than outright exposure. Life is either a daring adventure or nothing."   Helen Keller

We are going to explore the racing N words NITROUS & NITRO!

Offline robfrey

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Re: NACA 66 Special A/BGS
« Reply #392 on: August 15, 2012, 12:50:59 AM »
This is where we need to stop for a bit. The Carbinite 04 Cobra needs put back together. Going to take a week or so.
If your at Speedweek please stop by the 3838 Corvette pit to say hi.



Wide track!






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Offline Peter Jack

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Re: NACA 66 Special A/BGS
« Reply #393 on: August 15, 2012, 01:41:15 AM »
Nice pictures. I really like the driver's area. The whole project shows a lot of craftsmanship.  :cheers: :cheers: :cheers:

Pete

Offline robfrey

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Re: NACA 66 Special A/BGS
« Reply #394 on: August 15, 2012, 09:15:45 AM »
Thank for the kind words Peter.

I would really like for everybody following this thread to know is that this car would not be what it is without the help of Mr. Tom Burkland. His unique incite and his willingness to share with us shaped the concept of this project. Not to mention how much time and effort he put into helping us engineer critical areas of design. As humble as Tom is he will probably be angry about writing this but I must give credit where it is due.
I can't help but think that God's intervention has brought people on board for this project that I could have never done on my own. We truly have an all star team!
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Blue

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Re: NACA 66 Special A/BGS
« Reply #395 on: August 17, 2012, 12:16:26 AM »
Eric has been making great strides with the body. Eric has requested that I don't post any pictures of the progress until we are all done.
That way he can post the progression from start to finish within a couple of post.
We plan on fitting the body to the chassis in October.
It has been interesting moving from cad to parts on the body.  The flap molding into what were essentially "boxes" went flawlessly and convinced us to go this route on any constant tapered sections.  We had planned on a male mold for the wing sections.  This didn't work as well as hoped, so we are re-doing it in the manner we did the flaps.

The fuselage has been an interesting challenge.  There are seven separate longitudinal control lines, all were gradient optimized with software I wrote, all were combined in cad and generated exquisitely smooth pressure and velocity contours when tested with CFD.  Wing down-force vs. flap angle agreed with predictions to 1%.  This meant that we could add bumps or blister fairings for anything that didn't fit with confidence and any joints aft of the laminar transition would be non-issues. 

The nose section all the way to the firewall will be one-piece, with some very innovative structural attachments that Rob has worked out.  We will have multiple points of support every few feet with no external fasteners to trip the laminar flow.  And yes, it will be easily removable for tech.  Once the nose goes on at the beginning of the week, it will probably stay.  All service items are aft of the firewall or accessed through the cockpit hatch.  We are debating about doing the engine/transmission area in 2 vs. 4 parts and we need to decide how much intermediate support we need in these areas.  This is a 500 psf car (essentially the aero stress level of a military trainer), and needs about 4X the attachment and skin stiffness of a top fueler.  One-piece hinged body shells will shatter at these speeds.

The challenge has proven to be the translation of the upper to side and lower to side control lines vs. the gradient optimization.  Each control line has certain features that line up differently vs. their station.  We solved the pressure recovery (aft) areas first and everything averaged out vs. the water jet forms within 20 to 40 thousandths.  The real challenge has been on the front end where we are seeing 50 to 90 thousandths variations to achieve a smooth contour.

I can tell everyone this:  Rob's plan of CAD-to-water-jet-to-foam-to-form, these are the cheapest and best molds I have ever produced.  Nothing shy of expensive high density form board and a gantry CNC mill could translate design intent to reality as well as this;  and that would have been 3 to 5X the cost. 

The only problem is that by designing a perfectly gradient optimized shape, we have bought into a continuously changing curveture at every point of every surface.  Even the slightest bulge or dip shows and there are no flat surfaces to just run a long board back and forth on.  It would have been so much easier to build a pointy-nosed-brick;  I wanted the low drag.  We have actually invented our own 3 and 5' conformal tools to achieve the required contour to +/-.010".  The linear parts like the wings, flaps, and wheel fairings are flat across their span so they are simple and quick to form even though they have continuous curveture in the chord axis.  The fuselage is a work of art, albeit an expedient one, and we will be publishing pics of it soon.

Congratulations to Rob and the 3838 Corvette team on their record and red hat on their first time out.  I had the priviledge to spend a week with the Carbinite team in June and they are true professionals.  I had to stay home from speed week this year due to family health issues.  I look forward to going to Mike Cook's shootout after the air races.

Offline Jon

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Re: NACA 66 Special A/BGS
« Reply #396 on: August 17, 2012, 07:48:33 AM »

We have actually invented our own 3 and 5' conformal tools to achieve the required contour to +/-.010".


Hi Eric, any chance of pics or details of these?

Thanks
jon
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Offline A2WindTunnel

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Re: NACA 66 Special A/BGS
« Reply #397 on: August 17, 2012, 08:42:27 AM »
Good stuff.  Looks like its coming along great.  Will there be additional support for the rear axle? It would seem under full load (even static) there would be deflection.  I worked on some fixtures for an Indy car at AeroDyn and with the shallow angle of the vertical supports (similar to what you have or will have when done) we were seeing the car deflect under wind loading (with the lazar height sensors) as much as 1/4 inch (+).  It happens so subtle that you could not see by eye and it was a surprise to see the numbers move on the team’s data readout. I had to go back and improve the design to eliminate the deflection. I know you are not going to produce as much downforce but then again you don’t have a 1400lbs car to begin with.  A 1400 lbs Indy car with 2K, 3K lbs downforce is still less overall then yours static (I’m guessing).

One simple way to test for deflection is use a square off the floor and mark the center section of the rear-end.  Then load it, heck have a few people stand on it to simulate the wet weight of the car and then see where your mark ends up.  Even if that is not the final design it would be good to test when done. Just my 2-cents.
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Offline SPARKY

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Re: NACA 66 Special A/BGS
« Reply #398 on: August 17, 2012, 09:20:19 AM »
JEEEZ what a great time to be associated with this sport---who could ever imagine that this web site would lead to such bonds of help and friendship and free exchange of ideas---this characteristic of this sport must be honored and protected ---thanks to all who contribute and share  :cheers:
Miss LIBERTY,  changing T.K.I.  to noise, dust, rust, BLUE HATS & hopefully not scrap!!

"Security is mostly a superstition. It does not exist in nature, nor do the children of men as a whole experience it. Avoiding danger is no safer in the long run than outright exposure. Life is either a daring adventure or nothing."   Helen Keller

We are going to explore the racing N words NITROUS & NITRO!

Offline Rex Schimmer

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Re: NACA 66 Special A/BGS
« Reply #399 on: August 17, 2012, 02:03:15 PM »
I had the privilege to stop by Eric's shop on my way to Bonneville and see the first part of the body mold for Rob's NACA66 car and I can tell you that Eric is a very driven and resourceful guy and the car is going to be exceptional. After spending some time with him I am redoing the body shape on my lakester design and also working on trying to make at least the front part of the body to be a fiberglass part similar to what Eric is doing on the NACA66 car. The potential advantages of NLF (Natural Laminar Flow) are huge but to be able to get to the point where your car is working in that condition requires a lot of work and accuracy.

Rex
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Offline SPARKY

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Re: NACA 66 Special A/BGS
« Reply #400 on: August 17, 2012, 02:07:01 PM »
I doubt that the wild weasel team will be tempted---yet  :-D
Miss LIBERTY,  changing T.K.I.  to noise, dust, rust, BLUE HATS & hopefully not scrap!!

"Security is mostly a superstition. It does not exist in nature, nor do the children of men as a whole experience it. Avoiding danger is no safer in the long run than outright exposure. Life is either a daring adventure or nothing."   Helen Keller

We are going to explore the racing N words NITROUS & NITRO!

Offline robfrey

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Re: NACA 66 Special A/BGS
« Reply #401 on: August 19, 2012, 04:31:08 PM »
Big thanks to Jdeleon!!!!
Here are the bottom spindle supports for the liner. Only needed 2 but he made us a spare.
This is a big donation to our project and we are very thankful. Beautiful workmanship!




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Offline jdeleon

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Re: NACA 66 Special A/BGS
« Reply #402 on: August 20, 2012, 05:03:23 PM »
Thanks for the kind words Rob.  I feel honored to be just a tiny part of this amazing project.  Please keep me in mind if I can help in any way.  Javier

Offline robfrey

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Re: NACA 66 Special A/BGS
« Reply #403 on: August 27, 2012, 05:46:19 PM »
Got the 21.5 " MTs mounted today.
I don't think these will work for us.
Hearing rumors that they grow too much  for the clearance we engineered for.
Also, they are very square shoulder design, not like the other MTs and they are about .5 " wider than advertised.
I could have made these work if I knew what I was dealing with earlier on but I don't want to cut off the front of the car to start over now. We will go back to original design of a solid aluminum roller. This is a shame. It would have been nice to use conventional tires.





I have a bunch of extra work in theses wheels getting them to run true. Bore was mfgd oversize so I had to weld them up and recut them on my buddy's cnc mill. Can't seem to win here.

On the brighter side Blue is making great progress on the fuselage body work! You guys should start putting the pressure on him to post the pics.
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Offline flathead ray

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Re: NACA 66 Special A/BGS
« Reply #404 on: August 27, 2012, 06:21:44 PM »
Rob  I will donate my flathead engine for testing [just kiddin]