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XL Flaps: Maximum down deflection.

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gfmjr_20(at)HOTMAIL.COM
Guest

Posted: Wed Feb 07, 2007 3:02 pm Post subject: XL Flaps: Maximum down deflection.

Paul--

  I fought the same issue when I built my flaps.  I could not get the 30 

degrees. I ended up with 26 degrees.  Based on previous comments on trim 

issues, I enlarged my elevator trim tab to full span. I can trim out flaps 

up to about 18-20 degrees. With full flap deflection I need to hold back 

stick



George May

zodiac 912s 44 hours

 	  Quote: 	
		  From: Paul Mulwitz <p.mulwitz(at)worldnet.att.net>

Reply-To: zenith-list(at)matronics.com

To: <zenith-list(at)matronics.com>

Subject: XL Flaps:  Maximum down deflection.

Date: Wed, 07 Feb 2007 12:18:08 -0800




<p.mulwitz(at)worldnet.att.net>



I have been fighting with the flap actuator motor on my XL and come up with 

a strange set of design conflicts.  The deflection called for on sheet 

6-S-3 calls for 30 degrees maximum deflection, but the design shown on 

6-B-19 can only produce about 20 degrees of deflection.



I spoke to Caleb at ZAC today and he promised to look into this issue and 

get back to me.  I also wanted to ask list members if anyone has run into 

this problem already.  What flap deflection have builders who finished 

their XLs  get?  A related question (according to Caleb) is whether the 

elevator trim can neutralize the pitch changes with full flaps.



I would appreciate any information related to XL flap deflection.



Thanks,



Paul

XL fuselage

-




	


_________________________________________________________________

FREE online classifieds from Windows Live Expo – buy and sell with people 

you know

p.mulwitz(at)worldnet.att
Guest

Posted: Wed Feb 07, 2007 4:17 pm Post subject: XL Flaps: Maximum down deflection.

Thanks everyone.  It sounds like Caleb was giving 

me straight skinny about the trim issue.  I think 

I do have the latest trim tab design - inset into 

the elevator and taking much of one side.  I 

still think the decision to reduce the flap 

deflection might have been related to the design 

problem as much as the trim issue, but I guess that doesn't really matter.



Can anyone tell me if the full flaps (30 degrees) 

is really helpful in dumping altitude?  Will 20 

degrees be a big improvement over no flaps at all?



I guess my choices at this point are whether to 

settle for the current limit of 20 degrees or 

demand or design a larger deflection.



Paul

XL fuselage

At 02:58 PM 2/7/2007, you wrote:

 	  Quote: 	
		  



Paul--

  I fought the same issue when I built my 

 flaps.  I could not get the 30 degrees. I ended 

 up with 26 degrees.  Based on previous comments 

 on trim issues, I enlarged my elevator trim tab 

 to full span. I can trim out flaps up to about 

 18-20 degrees. With full flap deflection I need to hold back stick



George May

zodiac 912s 44 hours

>From: Paul Mulwitz <p.mulwitz(at)worldnet.att.net>

>Reply-To: zenith-list(at)matronics.com

>To: <zenith-list(at)matronics.com>

>Subject: XL Flaps:  Maximum down deflection.

>Date: Wed, 07 Feb 2007 12:18:08 -0800

>

>

>

>I have been fighting with the flap actuator 

>motor on my XL and come up with a strange set 

>of design conflicts.  The deflection called for 

>on sheet 6-S-3 calls for 30 degrees maximum 

>deflection, but the design shown on 6-B-19 can 

>only produce about 20 degrees of deflection.

>

>I spoke to Caleb at ZAC today and he promised 

>to look into this issue and get back to me.  I 

>also wanted to ask list members if anyone has 

>run into this problem already.  What flap 

>deflection have builders who finished their 

>XLs  get?  A related question (according to 

>Caleb) is whether the elevator trim can 

>neutralize the pitch changes with full flaps.

>

>I would appreciate any information related to XL flap deflection.

>

>Thanks,

>

>Paul

>XL fuselage

>-

>

>



_________________________________________________________________

FREE online classifieds from Windows Live Expo  

buy and sell with people you know




	


---------------------------------------------

Paul Mulwitz

32013 NE Dial Road

Camas, WA 98607

---------------------------------------------

craig(at)craigandjean.com
Guest

Posted: Wed Feb 07, 2007 4:47 pm Post subject: XL Flaps: Maximum down deflection.

I recall a number of messages a while ago where a number of folks reported

they rarely used their flaps at all.



-- Craig

gfmjr_20(at)HOTMAIL.COM
Guest

Posted: Wed Feb 07, 2007 5:01 pm Post subject: XL Flaps: Maximum down deflection.

Full flaps ---27degrees  --70mph and you'll come down at about 60 degrees 

glide path



George May

601XL 912s --44 hours



_________________________________________________________________

FREE online classifieds from Windows Live Expo – buy and sell with people 

you know

amyvega2005(at)earthlink.
Guest

Posted: Wed Feb 07, 2007 6:40 pm Post subject: XL Flaps: Maximum down deflection.

live with 20 degrees and learn to slip to kill altitude



Juan



--

amyvega2005(at)earthlink.
Guest

Posted: Wed Feb 07, 2007 6:41 pm Post subject: XL Flaps: Maximum down deflection.

where I have an issue is on eleveator deflection, as I am only getting 26 degrees up elevator, any thoughts or similar issues out there?



JUan



--

Tim Juhl

Joined: 21 Mar 2006
Posts: 488
Location: "Thumb" of Michigan

Posted: Fri Feb 09, 2007 8:16 am Post subject: Re: XL Flaps: Maximum down deflection.

If you want to lose a bunch of altitude in a hurry without overspeeding the aircraft try a slip.   I fly a Aeronca L16A which has no flaps and don't really miss them.  When I put it into a slip it comes down like a rock (without gaining airspeed) - as soon as I release the slip I'm back flying at my desired attitude and airspeed.  The flat side of the XL should make it slip pretty good.



My understanding is that the flaps were added to the XL to get the stall speeds within the light sport category.



That said, when my plane is done I'm sure I'll use flaps on approach.  I will also experiment (at altitude) with slips with flaps extended as well as the ability of the aircraft to hold altitude and climb with full flaps.  



Tim

_________________
______________
CFII
Champ L16A flying
Zodiac XL - Jabiru 3300A
Almost done! It'll fly in spring!

p.mulwitz(at)worldnet.att
Guest

Posted: Fri Feb 09, 2007 11:05 am Post subject: XL Flaps: Maximum down deflection.

Hi Tim,



I understand the choice between using deep slips and flaps for 

creating a steep approach to landing.  I am not sure either one has 

much advantage over the other one.  Of course if you have a plane 

with no flaps you have no choice.  I guess the slip choice can be a 

little unnerving on inexperienced passengers, but I am not sure if 

this is an advantage or disadvantage.



The situation is a little different with takeoff.  A little flaps - 

perhaps 10 degrees - can greatly shorten your ground roll and might 

even allow you to climb at a higher angle.  This option doesn't exist 

on a plane with no flaps.



The situation I ran into while building my XL showed me several 

things about the kit and plans.



1.  The design has recently been changed to limit the flap deflection 

to 20 degrees instead of the 30 degrees the XL has had since its 

first prototype.  This was done without any mention to the buyer 

community - just a change that kit and plan buyers learn about as 

they reach that stage of building.



Perhaps the only reason for this change was to allow the elevator 

trim to neutralize the pitch with full flaps - something that 

apparently was not possible with 30 degrees of flaps.  According to 

my current flight instructor and fellow local EAA club member, this 

is a very important quality for a plane to have and is indeed 

required for part 23 certification.  His explanation talked about 

having a bee chase you around the cockpit on approach so you let go 

of the stick to defend yourself.



This change certainly had nothing to do with LSA stall speeds since 

they are specified without the use of flaps.



2.  The flap control design is very sensitive to the vertical 

position of the long control tube that connects the two flaps.  If 

this tube is mounted too low (as on my first attempt) then there is a 

collision between the large channel the tube is mounted on and the 

steel tube extension on the linear motor actuator.  This seems like a 

really bad problem to me.  The location of the control tube is not 

specified on the prints.  Instead, it is determined by a long string 

of events that lead to the exact location of the wing trailing 

edge.  I plan to suggest this specification be changed to help 

following builders avoid the problem I had.



3.  Reports from current XL owners indicate 20 degrees of flap 

deflection is sufficient for their flying needs and 30 is just plain 

overkill.  I suppose that means it is reasonable to accept the new 

design from ZAC even though it could have been changed in a more public way.



4.  As always, support from ZAC has been excellent.  In this case, 

Caleb spent time on this problem including several communications and 

parts of several days of effort.



Paul

XL fuselage

At 08:16 AM 2/9/2007, you wrote:

 	  Quote: 	
		  



If you want to lose a bunch of altitude in a hurry without 

overspeeding the aircraft try a slip.   I fly a Aeronca L16A which 

has no flaps and don't really miss them.  When I put it into a slip 

it comes down like a rock (without gaining airspeed) - as soon as I 

release the slip I'm back flying at my desired attitude and 

airspeed.  The flat side of the XL should make it slip pretty good.



My understanding is that the flaps were added to the XL to get the 

stall speeds within the light sport category.



That said, when my plane is done I'm sure I'll use flaps on 

approach.  I will also experiment (at altitude) with slips with 

flaps extended as well as the ability of the aircraft to hold 

altitude and climb with full flaps.



Tim



---

bryanmmartin

Joined: 10 Jan 2006
Posts: 1018

Posted: Fri Feb 09, 2007 2:01 pm Post subject: XL Flaps: Maximum down deflection.

I'd have to agree, you can put in full rudder and plenty of opposite 

aileron and drop the plane in like a brick. Full flaps will bring the 

nose down for better visibility over the nose during final approach but, 

for most runways, they aren't really necessary. The plane can easily be 

landed fully loaded with no flaps in less than 1200 feet or so.



 	  Quote: 	
		   

 

 If you want to lose a bunch of altitude in a hurry without overspeeding the aircraft try a slip.   I fly a Aeronca L16A which has no flaps and don't really miss them.  When I put it into a slip it comes down like a rock (without gaining airspeed) - as soon as I release the slip I'm back flying at my desired attitude and airspeed.  The flat side of the XL should make it slip pretty good.

 

 My understanding is that the flaps were added to the XL to get the stall speeds within the light sport category.

 

 That said, when my plane is done I'm sure I'll use flaps on approach.  I will also experiment (at altitude) with slips with flaps extended as well as the ability of the aircraft to hold altitude and climb with full flaps.  

 

 Tim

 

 


	


-- 

Bryan Martin

Zenith 601XL N61BM

Ram Subaru, Stratus redrive

Do Not Archive

_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive.

Tim Juhl

Joined: 21 Mar 2006
Posts: 488
Location: "Thumb" of Michigan

Posted: Fri Feb 09, 2007 4:52 pm Post subject: Re: XL Flaps: Maximum down deflection.

In aircraft with flaps, I routinely use them on landing.  When I had my C182 I also preferred using 20Â° on takeoff when light, even on paved runways - "up, up and away!"  



You are right about slips with passengers aboard.... I always make that part of the briefing.   I've made approaches to the local city airport where citizens have come racing to the field convinced that the "funny flying" airplane had crashed after viewing my slip on approach.



I like slips because you can lose a lot of altitude without building up a lot of extra speed or having to make dramatic power reductions.   Some guys who find themselves too high chop the power, drop the flaps and push the nose over....an altogether unsatisfactory situation in my view....  I like to keep my engine warm and happy and avoid long power off descents (shock cooling.)



Paul, I found your comments most interesting.  I'm going to file them away for when I get to that part of the build.   I got my kit last May so I assume I'm one of those who has the 20Â°flap travel although the plans still call for 30Â°.



Tim

_________________
______________
CFII
Champ L16A flying
Zodiac XL - Jabiru 3300A
Almost done! It'll fly in spring!

marinegunner(at)gmail.com
Guest

Posted: Fri Feb 09, 2007 6:18 pm Post subject: XL Flaps: Maximum down deflection.

Why not try a speed brake somewhere under the center fuselage?

-- 

Semper Fi,

Steven R. Hulland

CH 600 Taildragger

Amado, AZ



This and all other incoming/outgoing email, attachments and replies scanned prior to opening/sending and uses an external firewall to help insure virus free email and attachments.   [quote][b]

planecrazydld(at)yahoo.co
Guest

Posted: Tue Feb 13, 2007 2:30 pm Post subject: XL Flaps: Maximum down deflection.

Would there be adequate trim capability if the tab were full span on both elevators? I also plan to use something other than the elevator mounted trim motor design because I do not like the unbalanced controls in the first place.



Paul Mulwitz <p.mulwitz(at)worldnet.att.net> wrote:  [quote]--> Zenith-List message posted by: Paul Mulwitz 



Hi Tim,



I understand the choice between using deep slips and flaps for 

creating a steep approach to landing. I am not sure either one has 

much advantage over the other one. Of course if you have a plane 

with no flaps you have no choice. I guess the slip choice can be a 

little unnerving on inexperienced passengers, but I am not sure if 

this is an advantage or disadvantage.



The situation is a little different with takeoff. A little flaps - 

perhaps  10 degrees - can greatly shorten your ground roll and might 

even allow you to climb at a higher angle. This option doesn't exist 

on a plane with no flaps.



The situation I ran into while building my XL showed me several 

things about the kit and plans.



1. The design has recently been changed to limit the flap deflection 

to 20 degrees instead of the 30 degrees the XL has had since its 

first prototype. This was done without any mention to the buyer 

community - just a change that kit and plan buyers learn about as 

they reach that stage of building.



Perhaps the only reason for this change was to allow the elevator 

trim to neutralize the pitch with full flaps - something that 

apparently was not possible with 30 degrees of flaps. According to 

my current flight instructor and fellow local EAA club member, this 

is a very important quality for a plane to have and is indeed 

required for part 23 certification. His  explanation talked about 

having a bee chase you around the cockpit on approach so you let go 

of the stick to defend yourself.



This change certainly had nothing to do with LSA stall speeds since 

they are specified without the use of flaps.



2. The flap control design is very sensitive to the vertical 

position of the long control tube that connects the two flaps. If 

this tube is mounted too low (as on my first attempt) then there is a 

collision between the large channel the tube is mounted on and the 

steel tube extension on the linear motor actuator. This seems like a 

really bad problem to me. The location of the control tube is not 

specified on the prints. Instead, it is determined by a long string 

of events that lead to the exact location of the wing trailing 

edge. I plan to suggest this specification be changed to help 

following builders avoid the problem I had.



3. Reports from current XL owners indicate  20 degrees of flap 

deflection is sufficient for their flying needs and 30 is just plain 

overkill. I suppose that means it is reasonable to accept the new 

design from ZAC even though it could have been changed in a more public way.



4. As always, support from ZAC has been excellent. In this case, 

Caleb spent time on this problem including several communications and 

parts of several days of effort.



Paul

XL fuselage

At 08:16 AM 2/9/2007, you wrote:

[quote]--> Zenith-List message posted by: "Tim Juhl" 



If you want to lose a bunch of altitude in a hurry without 

overspeeding the aircraft try a slip. I fly a Aeronca L16A which 

has no flaps and don't really miss them. When I put it into a slip 

it comes down like a rock (without gaining airspeed) - as soon as I 

release the slip I'm back flying at my desired attitude and 

airspeed. The flat side of the XL should  Now that's room service! Choose from over 150,000 hotels 

in 45,000 destinations on Yahoo! Travel to find your fit.  	  Quote: 	
		  [b]

bryanmmartin

Joined: 10 Jan 2006
Posts: 1018

Posted: Tue Feb 13, 2007 2:47 pm Post subject: XL Flaps: Maximum down deflection.

There is a mod available for linking the flap mechanism to the elevator 

controls using a spring. This automatically adds extra nose up trim as 

the flaps deploy. It involves adding an extra lever to the center of the 

flap torque tube and linking it through a cable and spring to the stick. 

It would also preclude the situation where you might have too much trim. 

I'd hate to have the electric trim runaway and end up with so much up 

trim that it becomes very difficult to hold the nose down out of the 

stall region.



David Downey wrote:

 	  Quote: 	
		   Would there be adequate trim capability if the tab were full span on 

 both elevators? I also plan to use something other than the elevator 

 mounted trim motor design because I do not like the unbalanced controls 

 in the first place.

 


	


-- 

Bryan Martin

Zenith 601XL N61BM

Ram Subaru, Stratus redrive

Do Not Archive

_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive.

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