Exhaust Flow and Aero

[superford317]

Jimmy six.
I do not know the speeds you run at, but I am quiet sure that the air density difference is what allowed you to reach a faster top speed.
Even though the cool morning air is denser and your engine is making more power, the warmer evening air is less dense and more beneficial to lower drag.
double a given speed, drag quadruples.
at elevated speeds, a small gain in aerodynamics will be as good as a big gain in engine HP.
I have seen thousands of man hours and several thousand dollars thrown at engines and chassis in the name of speed, when it would have been much easier and cheaper to build in aerodynamics to the overall package in the beginning.
Think outside the box, I used to like to read smoky yuniks articles.

[WhizzbangK.C.]

Not to come across as a "Private Eye" or anything, but the authoritative tone that you take with your posting would lead one to believe that you have vast experience in this area. Nothing that you have posted yet says "in my opinion", but is all stated as fact without reference to any source material.

That and you won't give a simple answer to a direct question posed by 2 members in response to a single example that you have given.

At least your posts aren't all cut and paste stuff from other sources.

I checked your other posts, and your profile, didn't find the answer there, so I'll ask here, mainly because I and a lot of others like me spend a lot of time online looking for good info on this type subject, and when we think we've found it we spend a lot of hard earned time, money, and effort on trying to incorporate it into our builds. It is only natural that we would like to know that we can trust the source of this information. A little provenance goes a long way.

What is your background that provides you such an authoritative voice on such an esoteric subject.

And.

What is your name?

Franklin, perhaps?

If not please forgive me, but I seem to be seeing a familiar pattern here. 

[SPARKY]

L L,    my  my  the propster lives!!!  he has planted the seeds  lol   but a darn intresting read for sure

[superford317]

Hmmm, I have never had a response like this so far in my career.
I have devoted my entire human existence since the age of 10 to the internal combustion engine and anything to do with speed. I do not have children or a wife, I do not have time for them, and my only passion is speed and performance. When most people were out partying or spending time with friends, I was studying in schools and spending late nights in the shop modifying cylinder heads or building engines or chassis. I am currently working for the US government in a technical field in IRAQ the past 5 years.
as i type this i am only a few miles from syria and turkey, in the northern iraqi dessert.
I assure you that I am very well versed and educated in everything from aerodynamics to thermal dynamics and composites; I am a machinist, welder, fabricator and engine builder.
I have constructed many winning race cars from the ground up and consulted with the teams after they were on the track and winning.
I quoted a lap time to a team owner that a car would run to within .01 of a second, 3 months before I made delivery of it, the 3rd lap the first time ever on the track, it ran the time i had quoted.
I only wished to impart some of my understanding and knowledge that I have gained.
I have been busy answering E mails from people that have flooded me with questions since I started posting on this thread.
Things that come natural to me and I take for granted amazes most people when I start elaborating on them.
i elaborated at length and show you many examples, pictures and drawings. more so than i have seen elsewhere.

To answer your question the first ball is at 70, the second one is at 140 and the 3rd one is at 240.
These temperatures are easily obtainable on a vehicles body surface using several methods.
NASA only started doing research into this in the 1990s.

I am so sorry if I offended anyone, I assure you it will not happen again.

[Leadfoot]

Hey keep the posts coming . Very interesting to say the least !!

[jdincau]

the american F117 nighthawk low visability airplane used slits along the entire back width of the tail as an exhaust outlet, very wide and narrow.

However this configuration was not used for either propulsion or aerodynamic improvement but solely to hide the exhaust heat plume from the rear. It caused no end of headaches keeping the exhaust duct intact and the heat coatings at the rear attached.
Jim Dincau (34 years at the lazy L)

[jdincau]

the supermarine spitfire was the first to make use of this concept and the designers of the P-51 mustang said the meredith effect was a major factor for the P-51's high speed.
at 25,000ft altitude the hot air from the engine cooling radiators running through special ducting had 1/3 as much power as the proppeller had at full power.

Well i googled it and after reading through what was available on line, the consensus (and there were differing opinions) seemed to be that at BEST, oil and water cooler drag could be eliminated but no thrust was generated.

[superford317]

I was merely giving that as an example as to the shape and style, the same as the motorcycle fender.
The interior of the F117 exhaust ducts were lined with the same heat absorbing tiles as used on the space shuttle heat shield, to absorb heat and to protect the airplane.
All of this was used to help shield the exhaust so it could not be spotted by infra red signature, it mixed fresh cool air with the exhaust just before expelling it and the way that it was designed it could not be spotted from below.

[joea]

superford...thank you much for sharing your knowledge...could you share some
pictures of the many race cars you built from the ground up..?...it would be neat
to appreciate that....level of race winning engineering..

Joe

[jdincau]

The interior of the F117 exhaust ducts were lined with the same heat absorbing tiles as used on the space shuttle heat shield, to absorb heat and to protect the airplane.

I think not

[jdincau]

It just struck me.     57Tbird?

[superford317]

The oil cooler was a necessary evil for the airplane to function; overcoming the drag of the cooler was a big accomplishment and talked about for many years.
If it were not for the technological advances that allowed for the drag of the cooler to be overcome the airplane would have been much slower. As I stated earlier, at 25,000ft altitude the cooling system duct was putting out 1/3 as much thrust as the propeller was making at full power. The cooling system, making use of some ingenious ducting overcame its own drag, thus free power.
the cooling system for a 12 cylinder 1,700HP engine in 1944 was rather large, ovecomeing its own drag with only ducting was something that books have been written about and is still talkd about 70 years later.

[Glen]

I would think by now you would have given a name and other information that others have ask for. Can you do that and answer the other questions on what you have built and run. It's not much to ask for from the membership.

[SPARKY]

    

If my warped sense of humor offends you I am sorry Come out and identify yourself so that I may apologize!!

[jl222]

It just struck me.     57Tbird?

  T-bird couldn't spell

  .01 sec

                JL222