Today's Message Index:
----------------------
1. 12:50 AM - Re: 2-blade props (GRAHAM SINGLETON)
2. 04:27 AM - Re: 2-blade props (rampil)
3. 04:42 AM - Re: Re: 2-blade props (Gilles Thesee)
4. 05:03 AM - 1 1/4" gauges (Tony Renshaw)
5. 06:08 AM - Re: 2-blade props (Karl Heindl)
6. 07:50 AM - Re: Weight reduction - Brake Discs (Frans Veldman)
7. 08:00 AM - Re: Re: 2-blade props (Frans Veldman)
8. 08:00 AM - Re: Re: 2-blade props (Frans Veldman)
9. 10:26 AM - Le Touquet (David Joyce)
10. 12:22 PM - Re: Le Touquet (alan)
11. 12:36 PM - Re: 2-blade props (rampil)
12. 01:15 PM - Re: 1 1/4" gauges (Gerry Holland)
13. 02:36 PM - Re: 1 1/4" gauges (Paul McAllister)
14. 03:13 PM - Re: 1 1/4" gauges (jimpuglise@comcast.net)
15. 05:26 PM - Re: Re: 2-blade props (Karl Heindl)
Message 1
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| Subject: | Re: 2-blade props |
Karl=0ACost I suspect. Most things are a compromise=0A=0AGraham,=0A =0AWhy
do most GA aircraft have 2-blade props ?=0A =0AKarl=0A =0A=0A=0A =0A=0A=0A
=0A =0A________________________________=0A Date: Thu, 15 Apr 2010 22:54:04
eight reduction - Brake Discs=0ATo: europa-list@matronics.com=0A=0A =0AFran
s=0Ain theory only is a 2 blade more efficient, you get more vibration that
can't be balanced out. More vibration gives more disruption to laminar flo
w so more drag.=0AThis is also why 2 blade windmills are more likely to thr
ow blades. 2 blades don't cope with non axial air flow, multi blades do=0AG
raham=0A=0A=0A=0A=0A________________________________=0A From: Frans Veldman
<frans@privatepilots.nl>=0ATo: europa-list@matronics.com=0ASent: Thursday,
15 April, 2010 23:14:32=0ASubject: Re: Europa-List: Weight reduction - Bra
ke Discs=0A=0A=0A=0AGet a two blade prop. One blade of a CS prop is 4Kg's w
orth. Apart from=0Athat, it cruises more efficiently, cutting down on fuel
(read: weight).=0A=0AFrans=0A=0A=0A=0A=0A=0A>http://www.matronics.com/Navig
ator?Europa-List=0Aronics.com=0Aww.matronics.com/contribution=0A=0A=0A=0A
===============
Message 2
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| Subject: | Re: 2-blade props |
....most commercial GA aircraft have two blade props...
Actually as can be seen convincingly in a stroll about Sun and Fun
today, any new, high performance aircraft , i.e., Cirrus, Cessna,
Mooney, Lancair, etc., etc., has 3 blades.
Just because most aircraft designed 30 years ago or earlier had
two blades doesn't mean that it was best for aerodynamics, just
best for the marketplace at the time.
In the end I think Graham is correct, it was just about money.
Reporting from under the old Oak tree with the Europa Team!
Regards,
Ira
--------
Ira N224XS
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=294406#294406
Message 3
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| Subject: | Re: 2-blade props |
Ira and all,
> Actually as can be seen convincingly in a stroll about Sun and Fun
> today, any new, high performance aircraft , i.e., Cirrus, Cessna,
> Mooney, Lancair, etc., etc., has 3 blades.
>
Apart from what Karl said, the number of blades has something to do with
the prop *solidity* necessary to transfer power. The aircraft you cite
have powerful engines, hence the tendancy to increase the number of blades.
> Just because most aircraft designed 30 years ago or earlier had
> two blades doesn't mean that it was best for aerodynamics,
>
Our airplane and two-blade prop were designed just a few years ago, and
they are quite efficient aerdynamically.
Remember that more blades means more drag (I also owned an unlimited
aerobatics airplane with a 3 blade, and we performed comparative tests
with a 2 blade).
In some cases, 3 blades are needed with low power (100 hp) in order to
reduce prop diameter for clearance reasons.
> In the end I think Graham is correct, it was just about money.
>
Weight, parts count and efficiency also play a role.
Best regards,
--
Gilles
http://contrails.free.fr
Message 4
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Gidday,
Simple question............are 1 1/4" gauges too small?? Tossing up between one
of these and the larger 2 1/4" ones.
Reg
Tony Renshaw
Sydney Aussie.
Message 5
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Graham=2C
Yes=2C every choice has its pros and cons. If it hadn't been for my MG proj
ect=2C I would have been quite happy to carry on with the Warp Drive. It pe
rformed well=2C and you can't beat the exterior carbon finish=2C as opposed
to painted or varnished propellers.
But I also had to have feathering=2C and the Airmaster hub had become very
expensive. I am not really wild about automatic pitch control=3B I would pr
efer just manual=2C with an accurate display in percent or degrees of pitch
. I don't think there is such an animal.
Karl
From: grahamsingleton@btinternet.com
Subject: Re: Europa-List: 2-blade props
Karl
Cost I suspect. Most things are a compromise
Graham=2C
Why do most GA aircraft have 2-blade props ?
Karl
From: grahamsingleton@btinternet.com
Subject: Re: Europa-List: Weight reduction - Brake Discs
Frans
in theory only is a 2 blade more efficient=2C you get more vibration that c
an't be balanced out. More vibration gives more disruption to laminar flow
so more drag.
This is also why 2 blade windmills are more likely to throw blades. 2 blade
s don't cope with non axial air flow=2C multi blades do
Graham
From: Frans Veldman <frans@privatepilots.nl>
Sent: Thursday=2C 15 April=2C 2010 23:14:32
Subject: Re: Europa-List: Weight reduction - Brake Discs
Get a two blade prop. One blade of a CS prop is 4Kg's worth. Apart from
that=2C it cruises more efficiently=2C cutting down on fuel (read: weight).
Frans
>http://www.matronics.com/Navigator?Europa-List
ronics.com
ww.matronics.com/contribution
http://www.matronics.com/con===============
Message 6
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| Subject: | Re: Weight reduction - Brake Discs |
On 04/16/2010 12:54 AM, GRAHAM SINGLETON wrote:
> in theory only is a 2 blade more efficient, you get more vibration that
> can't be balanced out.
I agree about the vibration, although if this is a valid argument, why
not add even more blades? 7 blades gives even less vibration. ;-)
> More vibration gives more disruption to laminar
> flow so more drag.
Well, I can't follow this one. Can you explain why? The vibration of a
2-blade prop has nothing to do with the blade itself, but to the fact
that one blade is working harder than the other blade if the wind isn't
exactly axial. Each blade however doesn't "know" that there is another
blade. In fact, this same inbalance exists with a three blade prop, but
you just don't notice it because the "peaks" are no longer symmetrical
but 120 degrees out of phase. For the air flowing over a blade, it
doesn't matter though.
> This is also why 2 blade windmills are more likely to throw blades.
Not because of a less efficient airflow, but because vibrations can
weaken the attachment of the blades.
Luckily, airplanes have been flying for decennia with two blades, so
there is still enough knowledge to construct a blade that doesn't fall
apart.
Frans
Message 7
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| Subject: | Re: 2-blade props |
On 04/16/2010 01:41 PM, Gilles Thesee wrote:
> Apart from what Karl said, the number of blades has something to do with
> the prop *solidity* necessary to transfer power. The aircraft you cite
> have powerful engines, hence the tendancy to increase the number of blades.
Right. If you increase the amount of power, at some point you have to
increase the diameter of the prop. If you can't do this (for clearance
reasons), you will have to revert to adding some more blades. More
blades is a compromise.
> Our airplane and two-blade prop were designed just a few years ago, and
> they are quite efficient aerdynamically.
I can't think of ANY reason why more blades would be more efficient. I
can however think of reasons why less blades is more efficient.
Frans
Message 8
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| Subject: | Re: 2-blade props |
On 04/16/2010 01:26 PM, rampil wrote:
> ....most commercial GA aircraft have two blade props...
> Actually as can be seen convincingly in a stroll about Sun and Fun
> today, any new, high performance aircraft , i.e., Cirrus, Cessna,
> Mooney, Lancair, etc., etc., has 3 blades.
It has a lot to do with sound. A 3-blader produces less sound.
Furthermore it has less vibrations, and to some folks looks sexier.
Performance is another subject.
A 2-blade prop IS more efficient. The tips of the prop slice through the
air with almost the speed of sound, if you have two tips instead of
three, you reduce drag quite a lot.
If is the same question versus a two wing airplane or a bi-plane. A
bi-plane has more drag because it has more frontal wing surface. More
wings is not more efficient, just like more propeller blades is not more
efficient.
My propeller still converts the same amount of engine power to thrust,
but it has less frontal surface slicing through the air. Once I' flying,
I will be happy to share performance data.
And no, no first flight today. :-( The whole airspace has been shut-down
because of the volcanic ash.
> Just because most aircraft designed 30 years ago or earlier had
> two blades doesn't mean that it was best for aerodynamics, just
> best for the marketplace at the time.
Well, then this must have been the reason the bi- and three-plane
airplanes vanished from the market as well? Just because two wings was
cheaper?
Frans
Message 9
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Just a reminder to UK and near European pilots that the fly out to Le
Touquet happens on Sat 1 May. Hopefully by then the volcanic dust will have
gone away ( but I trust not to our friends over the pond!)
This is a fun day out for experienced pilots. We generally rent
bicycles and trundle into town to have a great lunch and buy the odd French
tart before returning. It is also designed to provide full support for first
timers to lose their channel virginity. Anyone interested contact me and I
will send you a full briefing sheet, which covers everything you might want
to know (except where to find the best French tarts!)
Regards, David Joyce, Europa Club Trips & Outings Coordinator
Message 10
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Check NOTAM, Le Touquet was closed/
Alan
#0303
David Joyce wrote:
> <davidjoyce@doctors.org.uk>
>
> Just a reminder to UK and near European pilots that the fly out to Le
> Touquet happens on Sat 1 May. Hopefully by then the volcanic dust will
> have gone away ( but I trust not to our friends over the pond!)
> This is a fun day out for experienced pilots. We generally rent
> bicycles and trundle into town to have a great lunch and buy the odd
> French tart before returning. It is also designed to provide full
> support for first timers to lose their channel virginity. Anyone
> interested contact me and I will send you a full briefing sheet, which
> covers everything you might want to know (except where to find the
> best French tarts!)
> Regards, David Joyce, Europa Club Trips & Outings Coordinator
>
>
Message 11
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| Subject: | Re: 2-blade props |
Actually 2 blades being longer radii get less efficient as the length
blade in the transonic or faster regime grows. More blades keeps the tips
out of the transonic regime by keeping the radius down.
Of course we will discuss this in detail at the "Engineering" meeting
this evening for the Europa group at SnF
Cheers,
Ira
--------
Ira N224XS
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=294470#294470
Message 12
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| Subject: | Re: 1 1/4" gauges |
Tony Hi!
I had Mitchell 1.25 Square Gauges in my Europa for analogue engine readout.
They were: Oil Temp. Oil Pressure, CHT and Coolant Temp.
I found them perfectly viewable and they gave good easy to assess feedback.
The only downside of analogue is having no 'alarm' conditions that can be
set for visual or audio warning.
Regards
Gerry
Message 13
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| Subject: | Re: 1 1/4" gauges |
Tony,
I have CHT, Oil & EHT UMA 1.25" gauges that your welcome to make an offer
for. They have never been used.
Paul
Message 14
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| Subject: | Re: 1 1/4" gauges |
Yes, and if you are going to use them, I have a UMA 1 1/4 resistive fuel ga
uge.=C2- Also for a good price.=C2- The size is actually very nice for
a Europa.
Jim Puglise
----- Original Message -----
From: "Paul McAllister" <paul.the.aviator@gmail.com>
Sent: Friday, April 16, 2010 5:30:24 PM GMT -05:00 US/Canada Eastern
Subject: Re: Europa-List: 1 1/4" gauges
Tony,
I have CHT, Oil & EHT=C2- UMA 1.25" gauges that your welcome to make an o
ffer for.=C2- They have never been used.
Paul
==
Message 15
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| Subject: | Re: 2-blade props |
>
Frans wrote :
>
> It has a lot to do with sound. A 3-blader produces less sound.
> Furthermore it has less vibrations=2C and to some folks looks sexier.
I am not sure about the sound difference. My 2-blader makes a very attracti
ve low-frequency sound. To me it appears quieter than the Warp Drive. You h
ave the same prop=2C so maybe you can sometime compare it to another Europa
.
Karl
>
> A 2-blade prop IS more efficient. The tips of the prop slice through the
> air with almost the speed of sound=2C if you have two tips instead of
> three=2C you reduce drag quite a lot.
> If is the same question versus a two wing airplane or a bi-plane. A
> bi-plane has more drag because it has more frontal wing surface. More
> wings is not more efficient=2C just like more propeller blades is not mor
e
> efficient.
>
> My propeller still converts the same amount of engine power to thrust=2C
> but it has less frontal surface slicing through the air. Once I' flying
=2C
> I will be happy to share performance data.
> And no=2C no first flight today. :-( The whole airspace has been shut-dow
n
> because of the volcanic ash.
>
> > Just because most aircraft designed 30 years ago or earlier had
> > two blades doesn't mean that it was best for aerodynamics=2C just
> > best for the marketplace at the time.
>
> Well=2C then this must have been the reason the bi- and three-plane
> airplanes vanished from the market as well? Just because two wings was
> cheaper?
>
> Frans
>
>
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>
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