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Posted for peon@pacific.net.au:
Hey Ed,
Maaaaaaaaaaaate, can we stop the non-sense about doing theoretical calculations, based on false prremises, which lead to eroneous conclusions?? This is a real EXPERIMENTAL aircraft newsletter, not one that devotes its time and energies to THEORETICAL interstellar rocket science. So if you my good friend, (or anyone else for that matter) want to prove that they DO or DON'T work, buy one. (I can sell the EWP and the Controller as a package deal for $550 AUD plus $65 AUD Air mail and packaging) Test it, and if it doesn't work as advertised, I'll not only cheerfully refund your money, I'll give you a free two week all expenses paid holiday for you and yours in Sydney, (all food & lodgings, sightseeing, dinner at CentrePoint Tower etc - but not including air fares to and from Sydney of course), with me acting as tour guide and personal chauffer as part of my penance. If however, on the other hand, it DOES work, then you can give ME a 2 week all expenses paid holiday in your home town!
See, we went down that road months ago. I even had some personal correspondence with you to get you to check my calcs. The reason for the power gain is that the EWP is not trying to force a gazillion GPH through a teenzy weenzy little annular orifice with sharp edges called a thermostat. The stock pump is made so as to flow sufficient water to cool the engine at idle in traffic with the air conditioner going full blast (little air flow through the heat exchangers) on the hottest day (45 Deg C) you ever did see. But at WOT @ 100 MPH on the road @ say 7,000 rpm, on a nice cold night (0 - 10 deg C), the therrmostat is well over half closed, and the rest of the colling water is being refluxed via the bypass hole. So the head on the stock pump is ENORMOUS, and hence it robs a LOT of power.
Rotary racers have known this since the cork company (Toyo Kogyo) started racing the little suckers back in the mid 60's..
The (then) solution was to fit a smaller crank pulley and bigger water pump pulley to slow the pump down and hence to reduce (but not eliminate) the power drain. See details on the Racing Beat site.
Contrawise, with the EWP, there are virtually NO restrictions, (the whole stock pump mess is removed and consigned to the scrap bin!) and the only head the pump EVER sees is the cooling system and heat exchanger passage bounday layer friction! All the EWP does is CIRCULATE the water. There is virtually NO head against which to pump has to push, and hence it doesn't need humugous amounts of power. This is why it only needs to draw 7.5 amps = 90 watts.
seem to remember that somebody once "proved" that a bumble bee couldn't possibly fly, but they do. Lots of people say that these EWPs can't work, but they do, and hundreds of them are being used by happy owners around Oz (and elsewhere).
Anyway, I'm off on 4 weeks recreation, but when I come back, our "new" RX7 Series III "Mule" is going to be fitted with an EWP, and it is going to cop the mother of all beatings on a chassis dyno. I've also decided to do the same series of tests on our 10A PP RX3, Under 2 litre class Club Car) See:
www.promotorsport.com.au
which quite happily zings to 10,500 RPM with stock pulleys. Should be interesting!! The old motor comes out on Saturday, A new motor is in the process of being built, and will be running shortly. Once it is run in, I will give it an unmerciful thrashing on the dyno as well.
This will all be carefully logged, and the data published on our new website (coming REAL soon now!!) so that this issue can be put to rest once and for all.
So stay tuned ... More coming ... I'm on a mission!!
Leon Promet
leon@promotorsport.com.au
On 16 Oct 2002, at 19:38, Ed Anderson wrote:
Leon kindly provide the webpage for the Davies EWP of recent
discussion (Thanks, Leon). I just took a look a the tech data on the
EWP that Todd is going to test out for aircraft application. The data
looks impressive. Taking one of the charts it shows that at 5500 rpm
for a typical? 6 cyl water pump engine that 6000 watts of power are
consumed by the mechanical water pump. From the data, it appears that
the Davies EWP can do the same cooling job for approx 105 watts of
energy (7.5 amps x 14 volts = 105 Watts). 6000 watts = approx 8.5 HP
or say a net gain of 6000-105 = 5895 Watts = 7.9 HP. So for say a
160HP engine installation that would be a useful HP gain of approx 5 %
- not too bad.
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