I do not believe a fuel saving of 33% is possible!
---From all my experience fuel burn is almost exactly related to air speed. It
takes a certain hp to drag a Europa through the air at a certain speed. This
hp can be achieved at high rpm low throttle or low rpm high throttle but the
hp remains the same. The only difference therefor is a slight change in
efficiency of the prop which is likely to be maybe 1 or 2%. A reduction in
rpm of 33% does not lead to the same saving in fuel consumption as throttle
settings are higher. I am ready to be proved wrong and am prepared to lend
for two weeks a fuel flow meter to anybody who wants to make the appropriate
tests.
Jerry
Flying Hi - Wish I was
jerry@flyinghi.demon.co.uk
http://www.avnet.co.uk/touchdown
-----Original Message-----
From: John Wigney <johnwigney@worldnet.att.net>
Date: 23 April 1999 02:14
Subject: Re: Sun 'N Fun Debrief?
>Dave,
>
>No gotchas that I am aware of. However, talked with Graham Singleton on
>subject of intermediate rudder bellcrank setup which he aftermarkets
>from the UK for XS kits. Rationale behind this item is the worst case of
>two pilots leaning on opposite rudder pedals in an emergency situation.
>Direct loads onto rudder horn and rudder hinges for this scenario can be
>very high (not sure but I think I remember + 400 lbs). Graham's mod puts
>in a bellcrank and mount ahead of the rudder which I understand is
>similar to the Classic Europa. This bellcrank takes these potential high
>loads off the rudder.
>
>A tip I picked up is not to put the XS fuselage top on until you have
>fitted just about everything including the flap linkage, etc.
>
>Shown in the tent were 2 props
>#1 was the Whirlwind 2 blade, VP, hydraulic. This prop is very light, ~9
>lbs. Catch 22 on this combo for the 912/914/912S engine is that the
>mounting pad for a hydraulic governor is the same as the pad for a
>vacuum pump. Therefore no vacuum instruments - electric instruments
>only. No info on performance of this prop on a Europa. I do not believe
>it has been flown yet.
>
>#2 was the electric Airmaster AP308 VP prop by Aero Trading Ltd. from
>New Zealand.
>See << http://www.propellor.com/ >>
>Offered with 3 blade Warp Drive or their own prop at same price, $3,800,
>with manual select of speed range. Additional auto controller is
>available at $650.
>This prop has been evaluated on the Lakeland demonstrator which
>apparently had some turbo problems during the testing work. Anyway,
>published results for 5,500 ft show as follows (hope the tabs transmit
>OK)
>
>ThrottleRPM Fixed kts Variable kts Increase
>100% 5800 122 123 +1
>60% 5500 119 124 +5
>55% 4800 103 121 +18
>40% 4200 94 112 +18
>Quote from Airmaster flyer "From the test results, there appears to be
>no significant increase in top speed. The greatest gain is at 55%
>throttle with the same speed obtained as at full throttle fixed pitch
>resulting in a 33% fuel saving."
>
>A lot of focus was given by the Europa staff on the new motor glider
>which by all accounts performs very nicely. Hope is to show
>plane?/wings? at Oshkosh.
>
>I heard preliminary talk on forming an East Coast builders' group a la
>Kim Prout in CA. Nothing definite yet.
>
>Anybody else ?
>
>Cheers, John, A099
>
>
>aviatordave@fuse.net wrote:
>>
>> Dear Europals,
>> Anybody out there is cyberspace willing to share what went on at Sun
>> 'N Fun?\
>> Any gotcha's or things that need to be transmitted to the troops?
>> Enquiring minds want to know!
>> Thanks,
>> Dave Conrad, A078, Cincinnati
>>
|