<VV> Fw: Adding Water to the Combustion Cycle

[J R Read]

I'm off of FastVair now, but the conversation bled over to VV.

The unsigned comment below comes from my son who just completed A&P a few months ago.

Later, JR


----- Original Message ----- 
From: viviset6 at comcast.net 
To: hmlinc at sbcglobal.net 
Sent: Friday, September 30, 2011 9:17 PM
Subject: Re: Adding Water to the Combustion Cycle


We studied this and most info seems right? Alcohol or water is misted into the induction system to cool the air entering the engine making it more dense increasing the volumetric efficiency and increasing the brake mean effective horse power. We had two continental engines on the areocomander that where supercharged and had this system.


-----Original message-----

  From: J R Read <hmlinc at sbcglobal.net>
  To: "Mike C. Read" <VIVISET6 at comcast.net>
  Sent: Sat, Oct 1, 2011 01:50:40 GMT+00:00
  Subject: Adding Water to the Combustion Cycle


  Interesting conversation that came up recently.
  Later, JR

  ----- Original Message ----- From: "Michael Kovacs" 
  To: 
  Cc: "VV" 
  Sent: Friday, September 30, 2011 6:21 PM
  Subject: Re: [fastvair] Adding Water to the Combustion Cycle


  > Frank is right.
  > The stuff I use to put into the big radial engine acft was called ADI > (anti
  > detonation injection). We mixed it up by the hundreds of gallons. It was > 49%
  > water 49% alcohol and 2% water soluble oil. With the big recips using > high
  > boost to take off on a hot day, the purpose was to keep detonation from
  > occurring which can result in a loss of power and possible engine damage.
  >
  >
  >
  > Reducing the possibility of detonation actually increases the horsepower > under
  > boost. I believe the engine designers of the big recips understood this. > However
  > you have to get to the situation of destructive detonation to have the ADI > work
  > for you.
  >
  > MIKE KOVACS
  >
  >
  >
  >
  > ________________________________
  > From: "FrankCB at aol.com" 
  > To: fastvair at yahoogroups.com; gadkinsj at yahoo.com
  > Sent: Fri, September 30, 2011 1:49:15 PM
  > Subject: [fastvair] Adding Water to the Combustion Cycle
  >
  >
  > Jerry,
  > The injected water does a lot more than simply "cool the engine". It > actually
  > takes part in the chemistry of combustion of the hydrocarbon gasoline. > As Sir
  > Harry Ricardo pointed out many decades ago, using water injection > actually
  > reduces MAXIMUM combustion pressure (that breaks things) while INCREASING > the
  > AVERAGE combustion pressure that makes TORQUE (engineers call it BMEP).
  >
  > Here's only one of many references you can follow:
  > http://www.eng-tips.com/faqs.cfm?fid=811
  >
  > Over 20,000 of our fighter aircraft used water injection during WW2 and > most of
  > these planes already had turbochargers/superchargers as well as > inter/after
  > coolers. Pratt and Whitney even carried out supplying water injection to
  > piston-engined commercial aircraft after WW2. Quoting from their 1947 > brochure
  > "Water Injection for Commercial Aircraft":
  > "Pratt & Whitney Aircraft has developed the war-proved Water Injection > System
  > for application to the Double Wasp and Wasp Major engines installed in
  > commercial aircraft. The use of water injection permits the safe increase > in
  > take-off horsepower by as much as 15%.......(This) is a fully developed > and
  > proved product. Over 20,000 fighter aircraft were provided with this > power
  > augmenter during World War II and the additional performance made > available
  > played a significant role in maintaining air supremacy."
  >
  > The fact that water injection can significantly eliminate pinging and
  > detonation even in NON-boosted engines shows that its effects extend far > beyond
  > simple cooling of the A/F mixture before combustion.
  >
  > Frank "chemical engineer" Burkhard
  > Boonton, NJ
  >
  >
  >
  > In a message dated 9/26/2011 10:30:38 A.M. Eastern Daylight Time,
  > gadkinsj at yahoo.com writes:
  > I also challenge Adding water to the Combustion cycle. It is true that > it
  > will help to cool the engine but that is because the Temp in the > combustion
  > chamber doesn't climb as high thus lowering the effective power > available to
  > the engine. I am of the opinion this would be a zero game with respect > to
  > Heat, and a loss with respect to volumetric efficiency as you are doing > work
  > to compress something that doesn't give you any work in return.