Today's Message Index:
----------------------
1. 06:16 AM - Aileron Trim & Deflection (Bob Miller)
2. 06:56 AM - 701 seat/flap (Flydog1966@aol.com)
3. 08:49 AM - Re: Aileron Trim & Deflection (bryanmmartin@comcast.net)
4. 08:57 AM - Slat Skin Support Angles - Rivet edge spacing... (Bima, Martin)
5. 09:50 AM - Re: Stratus Subaru cooling (John Karnes)
6. 12:19 PM - Re: Slat Skin Support Angles - Rivet edge spacing... (Ed Kramer)
7. 03:37 PM - Re: Stratus Subaru cooling (Leo Gates)
8. 03:57 PM - Re: Stratus Subaru cooling (John Karnes)
9. 04:00 PM - venturi troubles?? (John Karnes)
10. 05:26 PM - Re: venturi troubles?? (Ray Montagne)
11. 05:30 PM - Re: Stratus Subaru cooling (Leo Gates)
12. 05:48 PM - Re: Stratus Subaru cooling (Dave Austin)
13. 06:20 PM - Re: venturi troubles?? (Benford2@aol.com)
14. 07:28 PM - Re: Stratus Subaru cooling (Tim & Diane Shankland)
Message 1
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| Subject: | Aileron Trim & Deflection |
--> Zenith-List message posted by: "Bob Miller" <drmiller@cvillepsychology.net>
Time for public embarrassment. Dang!!
As Bryan Martin points out, my threaded rod idea won't work as described.
The ailerons would stay centered, not the stick, because the airstream is
still the only force acting on the ailerons.
I do understand that the deflected control surface creates drag, but there
would sure be less drag if the control surface could be deflected without
the additional drag of an opposing trim tab. To make my device work,
springs would be required to keep the stick centered, kind of like using
springs to return rudder pedals to center. I wonder how much spring
pressure would be required, and how it would affect the force necessary for
aileron control? In any event it's probably enough to undo the advantage of
using hinged ailerons.
Regarding weight in the right baggage compartment, it would require 57
pounds there to exert the same moment as a 200 # passenger. How would you
calculate which would have a greater impact on performance, additional
weight or aileron trim?
Bob
PS: If one has a header tank only, and for a given weight distribution,
wouldn't aileron trim would stay the same throughout all aspects of the
flight? (I'm thinking now of a ground adjustable trim tab if the spring and
threaded rod idea isn't practical.)
----- Original Message -----
From: <bryanmmartin@comcast.net>
Subject: Re: Zenith-List: 601 Alternative Aileron Trim
> --> Zenith-List message posted by: bryanmmartin@comcast.net
>
> If I'm reading your description correctly it seem you are describing a
device to deflect the ailerons enough to trim the airplane while keeping the
stick centered.
>
> First of all this adds some parts to the aileron control path and may
introduce more failure modes.
>
> Second this device will not have the desired effect. In order to trim the
airplane, you must deflect a control surface. This requires that a force be
exerted on the ailerons. This force can be exerted by a trim tab or the by
the control cables. Without a trim tab, the cables will still be exerting
the same force on the ailerons no matter what position the stick is in. In
order to conteract this trim force another force must be introduced, not
just a displacement of the control system. If your device were conected to a
spring and could be used to adjust the spring force on the control system,
it would have the desired effect.
>
> Some airplanes use an adjustable spring (or bungee cord system) to apply
trim forces, but this does not eliminate trim drag. The control surface is
still deflected which produces an increased drag. To eliminate trim drag the
only solution it to physically balance the airplane by adjusting the center
of gravity (i. e. put some luggage in the wing locker on the light side).
>
> Bryan Martin
Message 2
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--> Zenith-List message posted by: Flydog1966@aol.com
Zenith used to recomend 60-65 m.m. clearence between the seat bottom, and
the top of the gear channel. It seems they have some concearn about the seat
interfering with the flap leaver, and now recomend measuring down from the
top of the seat front 115 m.m. This will put the lowest part of the seat ~85
m.m. above
the floor, but only~50m.m. above the top of the gear channel. Less than
the
60-65 they used to recomend. Could anyone "De-confuse"me?
My dwgs are out in the garrage, but I think the channel height is
35m.m.,
and the seat front 200 m.m..
Thanks
Phil
do not archive
Message 3
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| Subject: | Re: Aileron Trim & Deflection |
--> Zenith-List message posted by: bryanmmartin@comcast.net
> --> Zenith-List message posted by: "Bob Miller" <drmiller@cvillepsychology.net>
>
> I do understand that the deflected control surface creates drag, but there
> would sure be less drag if the control surface could be deflected without
> the additional drag of an opposing trim tab.
The trim tab does create some small amount of additional drag but it does
have one advantage, if a control cable or linkage breaks, you can use the
trim tab to control the airplane to some degree. This might make it possible
to make a safe landing.
> To make my device work,
> springs would be required to keep the stick centered, kind of like using
> springs to return rudder pedals to center.
You don't really want to keep the stick centered, just balance the trim forces.
If the ailerons are deflected you want the stick deflected, otherwise you
may not be able to use full deflection in the other direction if needed.
> I wonder how much spring
> pressure would be required, and how it would affect the force necessary for
> aileron control? In any event it's probably enough to undo the advantage of
> using hinged ailerons.
Hinged ailerons will create more drag than the hingless ones unless you take
care to seal the hinge line gap. And yes, springs will affect the control
forces more than a trim tab.
>
> PS: If one has a header tank only, and for a given weight distribution,
> wouldn't aileron trim would stay the same throughout all aspects of the
> flight? (I'm thinking now of a ground adjustable trim tab if the spring and
> threaded rod idea isn't practical.)
>
Yes it would. Even with wing tanks, it's possible to keep the lateral CG nearly
constant by switching tanks at regular intervals. An ground adjustable trim
tab should work fine.
Bryan Martin
Do not archive
Message 4
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| Subject: | Slat Skin Support Angles - Rivet edge spacing... |
--> Zenith-List message posted by: "Bima, Martin" <mbima@hydro.mb.ca>
Is anyone else having trouble maintaining the 2D rivet center to edge
spacing for the skin support angles near the slat?
I can get it but with incredible effort.
Anybody have a easier method than shown in the manual?
Thanks
Martin Bima
Winnipeg, Canada
STOL-Vair
20%
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
<META NAME"Generator" CONTENT"MS Exchange Server version 5.5.2651.75">
Slat Skin Support Angles - Rivet edge spacing...
Is anyone else having trouble maintaining the 2D rivet center to edge spacing for
the skin support angles near the slat?
I can get it but with incredible effort.
Anybody have a easier method than shown in the manual?
Thanks
Martin Bima
Winnipeg, Canada
STOL-Vair
20%
Message 5
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| Subject: | Re: Stratus Subaru cooling |
--> Zenith-List message posted by: "John Karnes" <jpkarnes@earthlink.net>
> Did it make any difference?
Not really. Temps continued to climb toward 230 and had to abort climb
out every time...
> Did you do anything about the heat from the muffler and pipes and
> seal the radiator real well when you moved the radiator rearward?
No. I figured that the space between the two wouldn't need any heat
insulation. I did seal the radiator both behind and on the sides.
> Did you put anything on the outside of the radiator to assist the draw
> on the backside?
Someone just wrote and talked about facilitating draw of air through the
rad by establishing an area of lower pressure behind the rad. I was under
the belief that you wanted to force all the air past the cooling coils and
wanted to block the exit in the rear...
> Was your scoop designed to smooth the flow around the radiator elbows
> and over the end of the radiator?
No. I just constructed a flared box and riveted it onto the front of the
rad. I will say, though, that the muffler I had was one I inherited and
hung down in a position that I'm sure obstructed air flow. When I changed
to pipes and motorcycle mufflers for each header, and moved the rad to the
"chin," my temps dropped DRAMATICALLY. As I stated before, I established a
service ceiling of 12,500' on thursday and was on climb out the entire
time. At no time did the water temp ever reach 210 deg F.
Hope this helps...
John Karnes
Port Orchard, WA
N601JK
Message 6
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| Subject: | Re: Slat Skin Support Angles - Rivet edge spacing... |
--> Zenith-List message posted by: "Ed Kramer" <edair701@adelphia.net>
Martin,
If your talking about the "L" channel that gets bent to the contour of
the nose ribs at the slat support. I remember having to be extra careful
cutting the notch for the bend. 2-D can be maintained with some difficulty.
Ed Kramer
West Seneca, NY
CH 701
edair701@adelphia.net
Build Status:
Completed: Rudder, Left wing, Right wing.
Flaperons at 50%
>
> Is anyone else having trouble maintaining the 2D rivet center to edge
> spacing for the skin support angles near the slat?
>
> I can get it but with incredible effort.
>
> Anybody have a easier method than shown in the manual?
>
>
> Thanks
>
> Martin Bima
> Winnipeg, Canada
> STOL-Vair
> 20%
Message 7
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| Subject: | Re: Stratus Subaru cooling |
--> Zenith-List message posted by: Leo Gates <leogates@allvantage.com>
John Karnes wrote:
>--> Zenith-List message posted by: "John Karnes" <jpkarnes@earthlink.net>
>
>>Did you put anything on the outside of the radiator to assist the draw
>>on the backside?
>>
>>
>Someone just wrote and talked about facilitating draw of air through the
>rad by establishing an area of lower pressure behind the rad. I was under
>the belief that you wanted to force all the air past the cooling coils and
>wanted to block the exit in the rear...
>
OOPS! The key is to GET THE BAD AIR OUT! You can't push a string.
My erudite contribution.
Leo Gates
Message 8
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| Subject: | Re: Stratus Subaru cooling |
--> Zenith-List message posted by: "John Karnes" <jpkarnes@earthlink.net>
I was under
> >the belief that you wanted to force all the air past the cooling coils
and
> >wanted to block the exit in the rear...
> >
> OOPS! The key is to GET THE BAD AIR OUT! You can't push a string.
>
> My erudite contribution.
>
> Leo Gates
But isn't the "bad air" forced out the bottom of the rad past the cooling
coils and fins, thus creating the cooling effect you are after???
John Karnes
Message 9
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| Subject: | venturi troubles?? |
--> Zenith-List message posted by: "John Karnes" <jpkarnes@earthlink.net>
When I have been flying lately, my gyro horizon has started tumbling after
flying about 20-30 minutes. It is connected to a 4" venturi located on the
left bottom fuse. Is it possible that the venturi is icing up and losing
vacuum? OAT has been about 40 deg F.
John Karnes
Port Orchard, WA
N601JK
Message 10
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| Subject: | Re: venturi troubles?? |
--> Zenith-List message posted by: Ray Montagne <ac6qj@earthlink.net>
On 2/15/04 4:00 PM, "John Karnes" <jpkarnes@earthlink.net> wrote:
> --> Zenith-List message posted by: "John Karnes" <jpkarnes@earthlink.net>
>
> When I have been flying lately, my gyro horizon has started tumbling after
> flying about 20-30 minutes. It is connected to a 4" venturi located on the
> left bottom fuse. Is it possible that the venturi is icing up and losing
> vacuum? OAT has been about 40 deg F.
>
> John Karnes
> Port Orchard, WA
> N601JK
>
Absolutely possible! Remember that a Venturi is creating a low pressure
area and therefore a drop in temperature.
DO NOT ARCHIVE
Best Regards, Ray Montagne
Cupertino, CA
===========================================================================
Zenith Aircraft Zodiac CH-601-XL, Jabiru 3300
Construction Log & Photos: <http://home.earthlink.net/~ac6qj/zodiac>
Build Status: Rudder completed
Elevator Completed
Stabilizer Completed
Flaps Completed
Ailerons Completed
Right Wing Completed
Right Wing Tip Completed
Left Wing Completed
Right Wing Tip Completed
Fuselage Under Construction
NOTE: Heavy SPAM filters in place. Replies that do not include
the word 'Zenith' or 'Zodiac' will be rejected and will not
be viewable by me.
===========================================================================
Message 11
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| Subject: | Re: Stratus Subaru cooling |
--> Zenith-List message posted by: Leo Gates <leogates@allvantage.com>
John Karnes wrote:
>--> Zenith-List message posted by: "John Karnes" <jpkarnes@earthlink.net>
>
> I was under
>
>
>>>the belief that you wanted to force all the air past the cooling coils
>>>
>>>
>and
>
>
>>>wanted to block the exit in the rear...
>>>
>>>
>>>
>>OOPS! The key is to GET THE BAD AIR OUT! You can't push a string.
>>
>>My erudite contribution.
>>
>>Leo Gates
>>
>>
>
>But isn't the "bad air" forced out the bottom of the rad past the cooling
>coils and fins, thus creating the cooling effect you are after???
>
>John Karnes
>
>John,
>
The hot air needs to be sucked out. Forcing air into rad simply
compacts it, if it cant exit. The cool air will also expand further
compacting the flow. Rule of thumb - Three times the area of the inlet
for the outlet.
Leo
Message 12
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| Subject: | Re: Stratus Subaru cooling |
--> Zenith-List message posted by: "Dave Austin" <daveaustin2@sprint.ca>
Negative, John. The rad just becomes a flat plate pushing into the air.
Low pressure behind is the answer.
Think about Chris Heintz' answer to better cooling, which is to put a flange
on the cowl at the air exit at the bottom rear. That flange creates a low
pressure area to draw the hot air out of the cowl.
Dave Austin 601HDS - 912
Message 13
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| Subject: | Re: venturi troubles?? |
--> Zenith-List message posted by: Benford2@aol.com
In a message dated 2/15/2004 5:00:42 PM Mountain Standard Time,
jpkarnes@earthlink.net writes:
>
> When I have been flying lately, my gyro horizon has started tumbling after
> flying about 20-30 minutes. It is connected to a 4" venturi located on the
> left bottom fuse. Is it possible that the venturi is icing up and losing
> vacuum? OAT has been about 40 deg F.
>
> John Karnes
> Port Orchard, WA
> N601JK
>
What does your suction gauge read ????
Message 14
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| Subject: | Re: Stratus Subaru cooling |
--> Zenith-List message posted by: Tim & Diane Shankland <tshank@megsinet.net>
Thought I might as well throw my 2 cents in. I spent most of last
winter testing heater cores for my cooling system. The current
discussion is not putting all the pieces together. First, for any given
heat exchanger there is a relationship between the air pressure across
the core the the volume of air that goes through it. It no a matter of
push or pull it is a matter of differential. I order to have the
required volume of air go through the heat exchanger you must have a
certain pressure differential across the core. To provide that pressure
you must convert the kinetic energy of the moving air to pressure, this
is called pressure recovery. Likewise you must provide a path for the
heated air to escape. Pressure recovery mean that the velocity of the
incoming air must be slowed down , preferable without turbulence to
efficiently recover the pressure. That means that that you don't make a
funnel shaped scoop but the reverse, a smaller opening that enlarges to
the heat exchanger. This slows the air and recovers the pressure. The
amount of pressure required to move the air through the heat exchanger
depends on several variables one of the most prominent ones being the
thickness of the core. Automotive radiators are designed to work at
relatively low speed with little pressure recovery because they are
typically 3/4 inch thick, they also are quite large and perpendicular to
the air stream, not a problem for a car but not good for an airplane.
The heater core I am using are 1 1/2 inch thick and in my design require
3 inches of water pressure differential across the core to cool the
engine. The standard Zenith system has limited pressure recovery, is
located in an area of turbulence from the front landing gear and often
has the exhaust and engine heat going through it. My system has the heat
exchangers in the cowling. While my system is not yet flying (this
summer) I have the expressions for doing the calculations if anyone is
interested. Although not yet flying the physics and the field tests I
have performed looked good.
Tim Shankland
John Karnes wrote:
>--> Zenith-List message posted by: "John Karnes" <jpkarnes@earthlink.net>
>
> I was under
>
>
>>>the belief that you wanted to force all the air past the cooling coils
>>>
>>>
>and
>
>
>>>wanted to block the exit in the rear...
>>>
>>>
>>>
>>OOPS! The key is to GET THE BAD AIR OUT! You can't push a string.
>>
>>My erudite contribution.
>>
>>Leo Gates
>>
>>
>
>But isn't the "bad air" forced out the bottom of the rad past the cooling
>coils and fins, thus creating the cooling effect you are after???
>
>John Karnes
>
>
>
>
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