 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
dredmoody(at)cox.net
Guest
|
 Posted: Mon Jun 04, 2007 7:03 am Post subject: landing gear placement |
 |
|
The pros and cons were:
With a nose heavy plane and the flat side rearward, there is a tendancy of the nosewheel to come down hard after the mains touchdown. The result for some has been that the nose bungee bounces the nose back high enough to fly again due to the high AOA when the nose come up.
Vice versa, with the flat side of the main gear forward, if two heavyweight folk step on the entry steps at the same time, they may overcome the nose weight and cause the plane to sit on its tail end tie down.
The summary is that it depends on your preferrence and the final weight distribution of your plane. Fortunately, someone noted that if you have a bit of extra slack in your brake lines and don't mind the refitting work on wheel pants brackets, the gear can be changed later if you want to do so.
Dred
---- john butterfield <jdbutterfield(at)yahoo.com> wrote:
| Quote: |
hi list
i remember seeing a discussion regarding the direction
the landing gear faces. there were some statements as
to the center of gravity and how it was affected by
having the flat edge of the gear forward or rearward.
i can't seem to find it in the archeives. what are
the advantages/disadvantages of each direction. in
the zenith photo manual it shows the gear in the "not
recommended direction. makes me think that it is an
arbitrary decision.
|
| | - The Matronics Zenith-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Zenith-List |
|
|
|
| Back to top |
|
 |
lrepilot(at)yahoo.com
Guest
|
| Posted: Mon Jun 04, 2007 7:18 am Post subject: landing gear placement |
|
|
Michael Heintz told me that it was mainly dependent on
engine weight. The issue is the stick force required
to rotate on take off. A heavy engine would benefit
from the mains offset forward. ( more lever arm for
the horizontal stab).
Ken
--- john butterfield <jdbutterfield(at)yahoo.com> wrote:
| Quote: |
<jdbutterfield(at)yahoo.com>
hi list
i remember seeing a discussion regarding the
direction
the landing gear faces. there were some statements
as
to the center of gravity and how it was affected by
having the flat edge of the gear forward or
rearward.
i can't seem to find it in the archeives. what are
the advantages/disadvantages of each direction. in
the zenith photo manual it shows the gear in the
"not
recommended direction. makes me think that it is an
arbitrary decision.
john butterfield
601XL, corvair
torrance, ca
Moody friends. Drama queens. Your life? Nope! -
their life, your story. Play Sims Stories at Yahoo!
Games.
http://sims.yahoo.com/
browse
Subscriptions page,
FAQ,
http://www.matronics.com/Navigator?Zenith-List
Web Forums!
|
Looking for a deal? Find great prices on flights and hotels with Yahoo! FareChase.
http://farechase.yahoo.com/
| | - The Matronics Zenith-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Zenith-List |
|
|
|
| Back to top |
|
|
bryanmmartin
Joined: 10 Jan 2006
Posts: 1018
|
| Posted: Mon Jun 04, 2007 7:21 am Post subject: landing gear placement |
|
|
With the flat side aft, the main gear are a few inches farther behind the CG. This gives them a longer lever arm and makes it a bit harder to rotate on take off and gives a tendency to drop the nose gear abruptly on landing. This also puts a bit more weight on the nose gear. Putting the flat side forward will reduce these tendencies. It has been stated that putting the flat side forward will make it easier to drop the tail on the ground when climbing into the plane by way of the rear step. According to my calculations, even with the plane loaded for gross weight and most aft CG, climbing out of the plane by the rear step will not put the tail on the ground. If both try to climb out at once, that may be a different story but that can easily be avoided.
My gear legs have the flat face rearward because that was the way the plans showed it at the time. I have to ease the back pressure on the stick just after liftoff to avoid over-rotating and have to apply increased back pressure on touchdown to keep the nosewheel from dropping abruptly. This is not a real big deal and I've gotten used to this behavior. I never considered it dangerous, just a bit different than the planes I used to fly. If I were building it today, I would reverse the gear legs. Someday when I find the time, I will probably reverse my gear legs to improve the handling a bit. It's not a high priority with me though.
On Jun 4, 2007, at 10:33 AM, john butterfield wrote:
| Quote: | --> Zenith-List message posted by: john butterfield <jdbutterfield(at)yahoo.com (jdbutterfield(at)yahoo.com)>
hi list
i remember seeing a discussion regarding the direction
the landing gear faces. there were some statements as
to the center of gravity and how it was affected by
having the flat edge of the gear forward or rearward.
i can't seem to find it in the archeives. what are
the advantages/disadvantages of each direction. in
the zenith photo manual it shows the gear in the "not
recommended direction. makes me think that it is an
arbitrary decision.
john butterfield
601XL, corvair
torrance, ca
|
--
Bryan Martin
N61BM, CH 601 XL,
RAM Subaru, Stratus redrive.
[quote][b]
| | - The Matronics Zenith-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Zenith-List |
|
_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive. |
|
| Back to top |
|
|
p.mulwitz(at)worldnet.att
Guest
|
| Posted: Mon Jun 04, 2007 8:58 am Post subject: landing gear placement |
|
|
Hi Bryan,
I wonder if adding a little flaps on takeoff would ease this problem . . .
At 08:21 AM 6/4/2007, you wrote:
| Quote: | I have to ease the back pressure on the stick just after liftoff
to avoid over-rotating
|
Paul
XL fuselage
do not archive
| | - The Matronics Zenith-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Zenith-List |
|
|
|
| Back to top |
|
|
bryanmmartin
Joined: 10 Jan 2006
Posts: 1018
|
| Posted: Mon Jun 04, 2007 11:21 am Post subject: landing gear placement |
|
|
I doubt it. Landing with full flaps doesn't make the nose want to drop any slower. Normally, when the nosewheel touches down, the plane is through flying and is sitting solidly on its gear. You have to command a rotation to lift off. The tendency to over-rotate is strictly a matter of geometry. To rotate, the plane has to pivot around the main wheels. As soon as the wheels leave the ground, the plane wants to pivot around the CG, which is several inches farther forward. In effect, as soon as the plane lifts off, the lever arm of the elevators suddenly increases, giving them more torque. It's not a drastic effect, but it is noticeable. I've gotten used to the behavior and automatically correct for it now.
On Jun 4, 2007, at 12:58 PM, Paul Mulwitz wrote:
| Quote: | --> Zenith-List message posted by: Paul Mulwitz <p.mulwitz(at)worldnet.att.net (p.mulwitz(at)worldnet.att.net)>
Hi Bryan,
I wonder if adding a little flaps on takeoff would ease this problem . . .
At 08:21 AM 6/4/2007, you wrote:
| Quote: | I have to ease the back pressure on the stick just after liftoff to avoid over-rotating
|
|
--
Bryan Martin
N61BM, CH 601 XL,
RAM Subaru, Stratus redrive.
do not archive.
[quote][b]
| | - The Matronics Zenith-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Zenith-List |
|
_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive. |
|
| Back to top |
|
|
p.mulwitz(at)worldnet.att
Guest
|
| Posted: Mon Jun 04, 2007 12:25 pm Post subject: landing gear placement |
|
|
Hi Bryan,
The reason I asked about the takeoff flaps is a story I have heard that adding flaps requires nose up trim - just the opposite of Cessnas and Pipers. I thought maybe this condition would also apply to the takeoff so the nose up force on the stick for rotation might be counteracted by the nose down force of the flaps.
Anyway, I always like to use a little flaps on takeoff to get the plane in the air faster. I haven't yet flown an XP, but most planes that are not horribly under powered like a little flaps on takeoff. Higher performance planes require it.
Best regards,
Paul
At 12:21 PM 6/4/2007, you wrote:
[quote]I doubt it. Landing with full flaps doesn't make the nose want to drop any slower. Normally, when the nosewheel touches down, the plane is through flying and is sitting solidly on its gear. You have to command a rotation to lift off. The tendency to over-rotate is strictly a matter of geometry. To rotate, the plane has to pivot around the main wheels. As soon as the wheels leave the ground, the plane wants to pivot around the CG, which is several inches farther forward. In effect, as soon as the plane lifts off, the lever arm of the elevators suddenly increases, giving them more torque. It's not a drastic effect, but it is noticeable. I've gotten used to the behavior and automatically correct for it now.
On Jun 4, 2007, at 12:58 PM, Paul Mulwitz wrote:
| Quote: | --> Zenith-List message posted by: Paul Mulwitz < p.mulwitz(at)worldnet.att.net (p.mulwitz(at)worldnet.att.net)>
Hi Bryan,
I wonder if adding a little flaps on takeoff would ease this problem . . .
At 08:21 AM 6/4/2007, you wrote:
| Quote: | I have to ease the back pressure on the stick just after liftoff to avoid over-rotating
|
|
--
Bryan Martin
N61BM, CH 601 XL,
RAM Subaru, Stratus redrive.
do not archive.
[b]
| | - The Matronics Zenith-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Zenith-List |
|
|
|
| Back to top |
|
|
amyvega2005(at)earthlink.
Guest
|
| Posted: Mon Jun 04, 2007 12:35 pm Post subject: landing gear placement |
|
|
depends on placement of gear relative to CG. in the plans, you can put the mains flat side forward or flat side facing back. differnce in feal will be apparent. if the mains are facing flat side back on the heavier engines, more weight is on the nose gear so you will need to unstick the plane. on the mains facing forward, you can pitch the trim for take off at 60 knots, with a slight touch on the elevator up. Example would be trying to hold the nose off the runway on a a fast taxi. If you can hold the nose up at around 40 mph, you can trim the plane. A flap setting will actual pitch the p[lane down a bit. example when setting up for final, if you are trimmedat 60 knots, if you hit the flaps to 20degrees, the nose pitches up.
Juan
--
| | - The Matronics Zenith-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Zenith-List |
|
|
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
