Bill, John, The air pressure inside the cowl wants to open the nose gear door. You need a certain momentum to keep the doors closed. It is defined by the Force of the push rod (it remains the same unless we increase the diameter of the nose gear cylinder) x length of the arm The length of the arm can be changed by moving the attachment point of the push rod closer to the center of the airplane (this is what Brent Regan did if you read my earlier post). Unfortunately we can’t move the attachment point completely to the inside because the nose gear won’t fit in anymore. I hope I get to check it out on the weekend. I will make new brackets then. It will be a bent laser cut aluminum part that can be reproduced at almost no cost. If I find a sound solution I let you know and I can make the brackets for you. Ralf From: John Barrett [mailto:2thman1@gmail.com] Sent: Friday, June 21, 2013 10:15 AMTo: lml@lancaironline.netSubject: Re: [LML] Re: Nose gear check 4P update Hi Bill, I do vaguely recall that the brackets are either too small or in the wrong part of the door (per the manual) to get the proper mechanical advantage. I am thinking Brent Regan came up with the discovery and the advice for fixing. It's been a long time, but I think I either made new brackets or put them in a different place or both. I could send photos and dimensions if you'd like. My doors seem to function well although no one has flown formation with me to observe how they close in flight. Let me know, JohnSent from my iPad On Jun 19, 2013, at 9:03 PM, "William A. Hogarty" <billhogarty@gmail.com> wrote: Hello John: Yes, I think that we are talking about the same item Each nose gear door is actuated by linkage (rods) that attach to the door using a small "L" shaped aluminum bracket. It seem that if the bracket were a little larger, the pivot point (where the rod attaches) could be moved and thus apply a little more pressure to hold the doors closed in flight.. Any thoughts???? Bill H. On Wed, Jun 19, 2013 at 12:29 AM, John Barrett <2thman1@gmail.com> wrote: Hi again Bill, Is the bracket you are referring to the horn that the push rod is attached to? I'm not quite sure what the bracket is. JohnSent from my iPad On Jun 18, 2013, at 7:09 PM, "William A. Hogarty" <billhogarty@gmail.com> wrote: Hello John: I bought two replacement aluminum doors from Lancair; primarily because aluminum hinges are still in the plane and they have always worked well. Dropping the doors was a simple matter of pulling the hinge pins. I am interested in enlarging the brackets that activate the doors because both of the connecting rods ended up having a slight curve after about 180 hours so there is considerable pressure on those rods. In addition, the right door bracket had a noticeable bend in it that I would like to resolve. If you have any specs on your brackets, I sure would like to see them On Tue, Jun 18, 2013 at 9:32 AM, John Barrett <2thman1@gmail.com> wrote: Hello Bill. i made my nose gear doors out of graphite on my LIVP and used Carbinge to hinge them. Have about 70 hours on the plane now with no glitches. Very happy with the results. Can share design parameters if you are interested. I also made graphite angle bar to hang them, but that might be overkill with your engine already being mounted. Best,John BarrettN31VPSent from my iPad On Jun 18, 2013, at 8:46 AM, "William A. Hogarty" <billhogarty@gmail.com> wrote: Ralf: I am making up a new set of nose gear doors (don't ask).. If you fabricate a new door bracket, please let me know the how and what. And how they work. (maybe Brent has a pattern??? Appreciate the help. Regards Bill Hogarty On Tue, Jun 18, 2013 at 4:45 AM, Chris Zavatson <chris_zavatson@yahoo.com> wrote: Ralf,The Outback gear doors on the 320/360 suffered a similar fate. The original actuation scheme couldn't handle the air loads. A small pressure differential over a large area generates a lot of force. Chris Chris ZavatsonN91CZ 360stdwww.N91CZ.net From: "bronnenmeier@GROBSYSTEMS.COM" <bronnenmeier@GROBSYSTEMS.COM> To: lml@lancaironline.net Sent: Monday, June 17, 2013 11:08 AMSubject: [LML] Nose gear check 4P update Dear subscribers,I did the nose gear check as described Jack Morgan and Charlie Kohlerearlier. Everything went very smooth and the plane did not move at all even when the weight on the tail and chucks were removed.I cycled the gear 5 times and every time the nose gear door shutperfect. This leads to the conclusion that my door shuts perfect aftertake-off and reopens due to air-pressure like Brent Regan describes below.On the in-flight picture you can see how the door gets pushed open. Thiswas at a pretty low speed - approx. 140...150 kts indicated - I assumeit will get worse if I go faster.I attached pics of my nose gear linkage versus Brent Regan's improved nose gear linkage - if yours looks more like mine you probably have thesame problem.Since there was so much concern about my jacks I attached a pic of thegear check. My jacks work reliable and the plane sits sound on them. They just don't have enough stroke. That's why I have little platformsthat I slide in and out. The set up works reliable - it is just a littlemore work.... Ralf-----Original Message----- From: Brent Regan [mailto:brent@regandesigns.com] Sent: Wednesday, June 12, 2013 11:37 AMTo: Lancair Mailing ListSubject: Re: Nose gear check 4P Ralf writes:"A friend took a picture of the belly of my airplane in flight with thegear up. It looked to me that the nose gear door was not completelyclosed."The original factory nose gear door linkage geometry provided too low a mechanical advantage to keep the doors closed against the internalcowling air pressure during flight. On the door bracket, you need tofabricate a new part with the link ball hole rotated about the hingecenterline towards the AC center. This will give a larger effective moment arm when the doors are closed. A slight kink in the linkage armsis required. See pictures attached.BTW, Selecting Gear Up while on the wheels is an incredibly bad idea. Buy a decent pair of jacks NOW. Also, do NOT strap the spinner to lift the nose. Remove the top cowl and strap the propshaft.RegardsBren Regan--For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html
Bill, John,
The air pressure inside the cowl wants to open the nose gear door.
You need a certain momentum to keep the doors closed. It is defined by the Force of the push rod (it remains the same unless we increase the diameter of the nose gear cylinder) x length of the arm
The length of the arm can be changed by moving the attachment point of the push rod closer to the center of the airplane (this is what Brent Regan did if you read my earlier post).
Unfortunately we can’t move the attachment point completely to the inside because the nose gear won’t fit in anymore.
I hope I get to check it out on the weekend. I will make new brackets then. It will be a bent laser cut aluminum part that can be reproduced at almost no cost. If I find a sound solution I let you know and I can make the brackets for you.
Ralf
From: John Barrett [mailto:2thman1@gmail.com] Sent: Friday, June 21, 2013 10:15 AMTo: lml@lancaironline.netSubject: Re: [LML] Re: Nose gear check 4P update
Hi Bill,
I do vaguely recall that the brackets are either too small or in the wrong part of the door (per the manual) to get the proper mechanical advantage. I am thinking Brent Regan came up with the discovery and the advice for fixing. It's been a long time, but I think I either made new brackets or put them in a different place or both. I could send photos and dimensions if you'd like. My doors seem to function well although no one has flown formation with me to observe how they close in flight.
Let me know,
JohnSent from my iPad
On Jun 19, 2013, at 9:03 PM, "William A. Hogarty" <billhogarty@gmail.com> wrote:
Hello John: Yes, I think that we are talking about the same item Each nose gear door is actuated by linkage (rods) that attach to the door using a small "L" shaped aluminum bracket. It seem that if the bracket were a little larger, the pivot point (where the rod attaches) could be moved and thus apply a little more pressure to hold the doors closed in flight.. Any thoughts???? Bill H. On Wed, Jun 19, 2013 at 12:29 AM, John Barrett <2thman1@gmail.com> wrote: Hi again Bill, Is the bracket you are referring to the horn that the push rod is attached to? I'm not quite sure what the bracket is. JohnSent from my iPad On Jun 18, 2013, at 7:09 PM, "William A. Hogarty" <billhogarty@gmail.com> wrote: Hello John: I bought two replacement aluminum doors from Lancair; primarily because aluminum hinges are still in the plane and they have always worked well. Dropping the doors was a simple matter of pulling the hinge pins. I am interested in enlarging the brackets that activate the doors because both of the connecting rods ended up having a slight curve after about 180 hours so there is considerable pressure on those rods. In addition, the right door bracket had a noticeable bend in it that I would like to resolve. If you have any specs on your brackets, I sure would like to see them On Tue, Jun 18, 2013 at 9:32 AM, John Barrett <2thman1@gmail.com> wrote: Hello Bill. i made my nose gear doors out of graphite on my LIVP and used Carbinge to hinge them. Have about 70 hours on the plane now with no glitches. Very happy with the results. Can share design parameters if you are interested. I also made graphite angle bar to hang them, but that might be overkill with your engine already being mounted. Best,John BarrettN31VPSent from my iPad On Jun 18, 2013, at 8:46 AM, "William A. Hogarty" <billhogarty@gmail.com> wrote: Ralf: I am making up a new set of nose gear doors (don't ask).. If you fabricate a new door bracket, please let me know the how and what. And how they work. (maybe Brent has a pattern??? Appreciate the help. Regards Bill Hogarty On Tue, Jun 18, 2013 at 4:45 AM, Chris Zavatson <chris_zavatson@yahoo.com> wrote: Ralf,The Outback gear doors on the 320/360 suffered a similar fate. The original actuation scheme couldn't handle the air loads. A small pressure differential over a large area generates a lot of force. Chris Chris ZavatsonN91CZ 360stdwww.N91CZ.net From: "bronnenmeier@GROBSYSTEMS.COM" <bronnenmeier@GROBSYSTEMS.COM> To: lml@lancaironline.net Sent: Monday, June 17, 2013 11:08 AMSubject: [LML] Nose gear check 4P update Dear subscribers,I did the nose gear check as described Jack Morgan and Charlie Kohlerearlier. Everything went very smooth and the plane did not move at all even when the weight on the tail and chucks were removed.I cycled the gear 5 times and every time the nose gear door shutperfect. This leads to the conclusion that my door shuts perfect aftertake-off and reopens due to air-pressure like Brent Regan describes below.On the in-flight picture you can see how the door gets pushed open. Thiswas at a pretty low speed - approx. 140...150 kts indicated - I assumeit will get worse if I go faster.I attached pics of my nose gear linkage versus Brent Regan's improved nose gear linkage - if yours looks more like mine you probably have thesame problem.Since there was so much concern about my jacks I attached a pic of thegear check. My jacks work reliable and the plane sits sound on them. They just don't have enough stroke. That's why I have little platformsthat I slide in and out. The set up works reliable - it is just a littlemore work.... Ralf-----Original Message----- From: Brent Regan [mailto:brent@regandesigns.com] Sent: Wednesday, June 12, 2013 11:37 AMTo: Lancair Mailing ListSubject: Re: Nose gear check 4P Ralf writes:"A friend took a picture of the belly of my airplane in flight with thegear up. It looked to me that the nose gear door was not completelyclosed."The original factory nose gear door linkage geometry provided too low a mechanical advantage to keep the doors closed against the internalcowling air pressure during flight. On the door bracket, you need tofabricate a new part with the link ball hole rotated about the hingecenterline towards the AC center. This will give a larger effective moment arm when the doors are closed. A slight kink in the linkage armsis required. See pictures attached.BTW, Selecting Gear Up while on the wheels is an incredibly bad idea. Buy a decent pair of jacks NOW. Also, do NOT strap the spinner to lift the nose. Remove the top cowl and strap the propshaft.RegardsBren Regan--For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html
Hello John:
Yes, I think that we are talking about the same item
Each nose gear door is actuated by linkage (rods) that attach to the door using a small "L" shaped aluminum bracket.
It seem that if the bracket were a little larger, the pivot point (where the rod attaches) could be moved and thus apply a little more pressure to hold the doors closed in flight..
Any thoughts???? Bill H.
On Wed, Jun 19, 2013 at 12:29 AM, John Barrett <2thman1@gmail.com> wrote:
Hi again Bill,
Is the bracket you are referring to the horn that the push rod is attached to?
I'm not quite sure what the bracket is.
On Jun 18, 2013, at 7:09 PM, "William A. Hogarty" <billhogarty@gmail.com> wrote:
Hello John: I bought two replacement aluminum doors from Lancair; primarily because aluminum hinges are still in the plane and they have always worked well. Dropping the doors was a simple matter of pulling the hinge pins. I am interested in enlarging the brackets that activate the doors because both of the connecting rods ended up having a slight curve after about 180 hours so there is considerable pressure on those rods. In addition, the right door bracket had a noticeable bend in it that I would like to resolve. If you have any specs on your brackets, I sure would like to see them On Tue, Jun 18, 2013 at 9:32 AM, John Barrett <2thman1@gmail.com> wrote: Hello Bill. i made my nose gear doors out of graphite on my LIVP and used Carbinge to hinge them. Have about 70 hours on the plane now with no glitches. Very happy with the results. Can share design parameters if you are interested. I also made graphite angle bar to hang them, but that might be overkill with your engine already being mounted. Best,John BarrettN31VPSent from my iPad On Jun 18, 2013, at 8:46 AM, "William A. Hogarty" <billhogarty@gmail.com> wrote: Ralf: I am making up a new set of nose gear doors (don't ask).. If you fabricate a new door bracket, please let me know the how and what. And how they work. (maybe Brent has a pattern??? Appreciate the help. Regards Bill Hogarty On Tue, Jun 18, 2013 at 4:45 AM, Chris Zavatson <chris_zavatson@yahoo.com> wrote: Ralf,The Outback gear doors on the 320/360 suffered a similar fate. The original actuation scheme couldn't handle the air loads. A small pressure differential over a large area generates a lot of force. Chris Chris ZavatsonN91CZ 360stdwww.N91CZ.net From: "bronnenmeier@GROBSYSTEMS.COM" <bronnenmeier@GROBSYSTEMS.COM> To: lml@lancaironline.net Sent: Monday, June 17, 2013 11:08 AMSubject: [LML] Nose gear check 4P update Dear subscribers,I did the nose gear check as described Jack Morgan and Charlie Kohlerearlier. Everything went very smooth and the plane did not move at all even when the weight on the tail and chucks were removed.I cycled the gear 5 times and every time the nose gear door shutperfect. This leads to the conclusion that my door shuts perfect aftertake-off and reopens due to air-pressure like Brent Regan describes below.On the in-flight picture you can see how the door gets pushed open. Thiswas at a pretty low speed - approx. 140...150 kts indicated - I assumeit will get worse if I go faster.I attached pics of my nose gear linkage versus Brent Regan's improved nose gear linkage - if yours looks more like mine you probably have thesame problem.Since there was so much concern about my jacks I attached a pic of thegear check. My jacks work reliable and the plane sits sound on them. They just don't have enough stroke. That's why I have little platformsthat I slide in and out. The set up works reliable - it is just a littlemore work.... Ralf-----Original Message----- From: Brent Regan [mailto:brent@regandesigns.com] Sent: Wednesday, June 12, 2013 11:37 AMTo: Lancair Mailing ListSubject: Re: Nose gear check 4P Ralf writes:"A friend took a picture of the belly of my airplane in flight with thegear up. It looked to me that the nose gear door was not completelyclosed."The original factory nose gear door linkage geometry provided too low a mechanical advantage to keep the doors closed against the internalcowling air pressure during flight. On the door bracket, you need tofabricate a new part with the link ball hole rotated about the hingecenterline towards the AC center. This will give a larger effective moment arm when the doors are closed. A slight kink in the linkage armsis required. See pictures attached.BTW, Selecting Gear Up while on the wheels is an incredibly bad idea. Buy a decent pair of jacks NOW. Also, do NOT strap the spinner to lift the nose. Remove the top cowl and strap the propshaft.RegardsBren Regan--For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html
I bought two replacement aluminum doors from Lancair; primarily because aluminum hinges are still in the plane and they have always worked well. Dropping the doors was a simple matter of pulling the hinge pins.
I am interested in enlarging the brackets that activate the doors because both of the connecting rods ended up having a slight curve after about 180 hours so there is considerable pressure on those rods. In addition, the right door bracket had a noticeable bend in it that I would like to resolve. If you have any specs on your brackets, I sure would like to see them
On Tue, Jun 18, 2013 at 9:32 AM, John Barrett <2thman1@gmail.com> wrote:
Hello Bill.
i made my nose gear doors out of graphite on my LIVP and used Carbinge to hinge them. Have about 70 hours on the plane now with no glitches. Very happy with the results. Can share design parameters if you are interested.
I also made graphite angle bar to hang them, but that might be overkill with your engine already being mounted.
Best,
John Barrett
N31VPSent from my iPad
On Jun 18, 2013, at 8:46 AM, "William A. Hogarty" <billhogarty@gmail.com> wrote:
Ralf: I am making up a new set of nose gear doors (don't ask).. If you fabricate a new door bracket, please let me know the how and what. And how they work. (maybe Brent has a pattern??? Appreciate the help. Regards Bill Hogarty On Tue, Jun 18, 2013 at 4:45 AM, Chris Zavatson <chris_zavatson@yahoo.com> wrote: Ralf,The Outback gear doors on the 320/360 suffered a similar fate. The original actuation scheme couldn't handle the air loads. A small pressure differential over a large area generates a lot of force. Chris Chris ZavatsonN91CZ 360stdwww.N91CZ.net From: "bronnenmeier@GROBSYSTEMS.COM" <bronnenmeier@GROBSYSTEMS.COM> To: lml@lancaironline.net Sent: Monday, June 17, 2013 11:08 AMSubject: [LML] Nose gear check 4P update Dear subscribers,I did the nose gear check as described Jack Morgan and Charlie Kohlerearlier. Everything went very smooth and the plane did not move at all even when the weight on the tail and chucks were removed.I cycled the gear 5 times and every time the nose gear door shutperfect. This leads to the conclusion that my door shuts perfect aftertake-off and reopens due to air-pressure like Brent Regan describes below.On the in-flight picture you can see how the door gets pushed open. Thiswas at a pretty low speed - approx. 140...150 kts indicated - I assumeit will get worse if I go faster.I attached pics of my nose gear linkage versus Brent Regan's improved nose gear linkage - if yours looks more like mine you probably have thesame problem.Since there was so much concern about my jacks I attached a pic of thegear check. My jacks work reliable and the plane sits sound on them. They just don't have enough stroke. That's why I have little platformsthat I slide in and out. The set up works reliable - it is just a littlemore work.... Ralf-----Original Message----- From: Brent Regan [mailto:brent@regandesigns.com] Sent: Wednesday, June 12, 2013 11:37 AMTo: Lancair Mailing ListSubject: Re: Nose gear check 4P Ralf writes:"A friend took a picture of the belly of my airplane in flight with thegear up. It looked to me that the nose gear door was not completelyclosed."The original factory nose gear door linkage geometry provided too low a mechanical advantage to keep the doors closed against the internalcowling air pressure during flight. On the door bracket, you need tofabricate a new part with the link ball hole rotated about the hingecenterline towards the AC center. This will give a larger effective moment arm when the doors are closed. A slight kink in the linkage armsis required. See pictures attached.BTW, Selecting Gear Up while on the wheels is an incredibly bad idea. Buy a decent pair of jacks NOW. Also, do NOT strap the spinner to lift the nose. Remove the top cowl and strap the propshaft.RegardsBren Regan--For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html
Ralf:
I am making up a new set of nose gear doors (don't ask)..
If you fabricate a new door bracket, please let me know the how and what. And how they work. (maybe Brent has a pattern???
Appreciate the help.
Regards
Bill Hogarty
On Tue, Jun 18, 2013 at 4:45 AM, Chris Zavatson <chris_zavatson@yahoo.com> wrote:
Ralf,
The Outback gear doors on the 320/360 suffered a similar fate. The original actuation scheme couldn't handle the air loads. A small pressure differential over a large area generates a lot of force.
Chris
Chris Zavatson
N91CZ
360std
www.N91CZ.net
From: "bronnenmeier@GROBSYSTEMS.COM" <bronnenmeier@GROBSYSTEMS.COM> To: lml@lancaironline.net Sent: Monday, June 17, 2013 11:08 AMSubject: [LML] Nose gear check 4P update
Dear subscribers,I did the nose gear check as described Jack Morgan and Charlie Kohlerearlier. Everything went very smooth and the plane did not move at all even when the weight on the tail and chucks were removed.I cycled the gear 5 times and every time the nose gear door shutperfect. This leads to the conclusion that my door shuts perfect aftertake-off and reopens due to air-pressure like Brent Regan describes below.On the in-flight picture you can see how the door gets pushed open. Thiswas at a pretty low speed - approx. 140...150 kts indicated - I assumeit will get worse if I go faster.I attached pics of my nose gear linkage versus Brent Regan's improved nose gear linkage - if yours looks more like mine you probably have thesame problem.Since there was so much concern about my jacks I attached a pic of thegear check. My jacks work reliable and the plane sits sound on them. They just don't have enough stroke. That's why I have little platformsthat I slide in and out. The set up works reliable - it is just a littlemore work.... Ralf-----Original Message----- From: Brent Regan [mailto:brent@regandesigns.com] Sent: Wednesday, June 12, 2013 11:37 AMTo: Lancair Mailing ListSubject: Re: Nose gear check 4P Ralf writes:"A friend took a picture of the belly of my airplane in flight with thegear up. It looked to me that the nose gear door was not completelyclosed."The original factory nose gear door linkage geometry provided too low a mechanical advantage to keep the doors closed against the internalcowling air pressure during flight. On the door bracket, you need tofabricate a new part with the link ball hole rotated about the hingecenterline towards the AC center. This will give a larger effective moment arm when the doors are closed. A slight kink in the linkage armsis required. See pictures attached.BTW, Selecting Gear Up while on the wheels is an incredibly bad idea. Buy a decent pair of jacks NOW. Also, do NOT strap the spinner to lift the nose. Remove the top cowl and strap the propshaft.RegardsBren Regan--For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html