NACA 66 Special A/BGS

[maguromic]

How much whp is required to push your average lakester or streamliner over 300?  Hmmmmm? Why?

Great build guys, I cant wait to see it run!  Tony

[Peter Jack]

It looks like the surrounding air is going to be really happy! Happy air should make for happy racers.   

Pete

[robfrey]

It looks like the surrounding air is going to be really happy! Happy air should make for happy racers.    

Pete

Thanks Jack! Yes, we are hoping for Happy racers!

[robfrey]

How much whp is required to push your average lakester or streamliner over 300?  Hmmmmm? Why?

Great build guys, I cant wait to see it run!  Tony

Thanks Tony!

[JoshH]

Rob - have you done any simulations with exhaust flow included? That placement is going to be critical in keeping things clean.

[robfrey]

With the our present technology, we cannot do that. At least I think we cant.
We would have to open the side ducts to ingest about 2400 cfms (1200 per side) and magnify it 3 times and shoot it out the exhaust.
We have a TON of thought into this but at this time we just have to apply what Eric has learned in the aviation industry.
We were going to have fairings for the exhaust pipes but I think we will be able to make long baloney cuts on the tubes until they are flush to the bodywork.
There has been a lot of engineering that went into the shape of the pipe because we are looking for a specific geometry at the blend point just as the pipes exit the bodywork. 
The flush inlet ducts will only ingest a small percentage of air crossing the duct opening and the back of the duct will be shaped so that the excess air will reattach to bodywork. Again, not sure what the cfd could show us here.

BTW, great question. Too many times the question of what we will do with the exhaust becomes an afterthought. We tried not to let that happen here.

[JoshH]

Thought spent on this is going to pay dividends. Fairings to transition the exhaust into the mainstream seems like a good idea, maybe plan your mounting so it can handle different iterations so you have some room to play.

The other thing to consider is how the placement of those outlets will affect the down force (or not?) of the rear airfoil that fairs the axle tubes in. But I suspect the exits are largely dependent on the turbo's and chassis anyway. Its going to be interesting.

[WOODY@DDLLC]

With the our present technology, we cannot do that. At least I think we cant.
We would have to open the side ducts to ingest about 2400 cfms (1200 per side) and magnify it 3 times and shoot it out the exhaust.
We have a TON of thought into this but at this time we just have to apply what Eric has learned in the aviation industry.
We were going to have fairings for the exhaust pipes but I think we will be able to make long baloney cuts on the tubes until they are flush to the bodywork.
There has been a lot of engineering that went into the shape of the pipe because we are looking for a specific geometry at the blend point just as the pipes exit the bodywork. 
The flush inlet ducts will only ingest a small percentage of air crossing the duct opening and the back of the duct will be shaped so that the excess air will reattach to bodywork. Again, not sure what the cfd could show us here.

BTW, great question. Too many times the question of what we will do with the exhaust becomes an afterthought. We tried not to let that happen here.

Rob, It is a non-obvious set-up but it can be done. I will PM you a wmv of a test model I did while working on Sparky's Thud Spud! Meantime here is a screenshot.

[rd400f]

Hi
WOODY@DDLLC.....Is that Solidworks Flo Simulation that you are using?
If it is which year do you have?
Thanks
Richard

[WOODY@DDLLC]

Hi
WOODY@DDLLC.....Is that Solidworks Flo Simulation that you are using?
If it is which year do you have?
Thanks
Richard

Richard, I use FS 2009 for setup & small jobs and FS 2012 for the big runs. One core w/4MB vs 6 cores w/12MB. Sometimes no substitute for cubic inches! 

[robfrey]

Do we need these upright bars (shown darker) to comply with rules or is the 1/4" forward bulkhead sufficient?

[SPARKY]

Rob the bulk head is under tension between the  two frame rails  I would be tempted to move the top toward the center ot the long diagional which appears to me to be under compression. 
That should help it stay straight instead wanting to kick out.  :|

[Rex Schimmer]

Rob,
I see the bulk head as possible area of high stress during an "unplanned event" that could actually cause the chassis to severely bend of fail at the bulkhead weld junctions. I would suggest that you use a piece of 1-1/2 x 2 (or 2 1/2) rectangular tube that would both pick up the rear tube junction and also be against the bulk head such that you could then weld it to the bulk head. Now you have the chassis loads all going through tube structure and the bulk head is stabilized and also better integrated into the chassis.

Just a thought,
Rex

[Tman]

That rectangular tubing is a great idea Rex.

[robfrey]

Rex,
All through the design stages, I've considered that it may not be a bad thing if the whole front snout of the car breaks off at the forward bulkhead/ firewall in the event of unplanned incident. I'm also planing on it breaking off behind the driver.
I had planned on using 1-1/2 x 1/8 wall sq tubing welded to the tubes and firewall but fit up is really tricky and I'm not sure I can put them in in one piece. The tubes are not parallel to the firewall which adds to the complexity of the fitup.
I'm really looking forward to your visit! Lots to discuss.