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jonealjr
Joined: 10 Feb 2017 Posts: 23
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neilsenrm(at)gmail.com Guest
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Posted: Mon Jun 12, 2017 1:11 pm Post subject: Strange Flying characteristics of new to me Mark III clasic |
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A Kolb with lots of power does take a bit of rudder to keep it flying straight. Most people add a trim tab to reduce the effect.
A Kolb that wants to roll right or left is a plane that isn't rigged right. The common cause is the wings aren't flying with the same pitch or angle of attack. Kolb sells a wide aft wing attachment fitting that allows one wing to be adjusted by moving washers around on the attachment bolt to trim out minor alignment issues. Use one on both wings for more adjustment. Some people add a bungee cord that pulls the stick to the side. I trim my plane for neutral stick force flying solo but requires a bit of pressure with a passenger. Kolbs are almost never able to fly hands off.
As usual worth what you paid for it.
Rick Neilsen
Redrive VW Powered MKIIIC
On Mon, Jun 12, 2017 at 4:31 PM, jonealjr <jonealjr(at)gmail.com (jonealjr(at)gmail.com)> wrote:
Quote: | --> Kolb-List message posted by: "jonealjr" <jonealjr(at)gmail.com (jonealjr(at)gmail.com)>
PLEASE HELP IF ANYONE HAS EXPERIENCE WITH THIS
I have a mark III classic w 912 uls Acting odd during taxi needs lots of left rudder to keep on the runway with tail on and off the ground and while flying needs lots of right stick to keep plane level. If you let go of the controls during straight and level flight the plane wants to roll to the left has anyone had similar experiences and or has anybody had any luck with adjusting engine mounts changing the thrust angle to help with aileron trim etc
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=470012#470012
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rickofudall
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Joined: 19 Sep 2009 Posts: 1392 Location: Udall, KS, USA
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Posted: Mon Jun 12, 2017 3:29 pm Post subject: Strange Flying characteristics of new to me Mark III clasic |
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If you don't have a set of plans and the construction book you should contact the factory. I've attached the factory blue print for the rudder trim tab required. For the roll issue first make sure the flaps are rigged correctly then you need to check the angle of incidence of each wing and the horizontal stabilizers.
Rick Girard
On Mon, Jun 12, 2017 at 4:11 PM, Rick Neilsen <neilsenrm(at)gmail.com (neilsenrm(at)gmail.com)> wrote:
Quote: | A Kolb with lots of power does take a bit of rudder to keep it flying straight. Most people add a trim tab to reduce the effect.
A Kolb that wants to roll right or left is a plane that isn't rigged right. The common cause is the wings aren't flying with the same pitch or angle of attack. Kolb sells a wide aft wing attachment fitting that allows one wing to be adjusted by moving washers around on the attachment bolt to trim out minor alignment issues. Use one on both wings for more adjustment. Some people add a bungee cord that pulls the stick to the side. I trim my plane for neutral stick force flying solo but requires a bit of pressure with a passenger. Kolbs are almost never able to fly hands off.
As usual worth what you paid for it.
Rick Neilsen
Redrive VW Powered MKIIIC
On Mon, Jun 12, 2017 at 4:31 PM, jonealjr <jonealjr(at)gmail.com (jonealjr(at)gmail.com)> wrote:
Quote: | --> Kolb-List message posted by: "jonealjr" <jonealjr(at)gmail.com (jonealjr(at)gmail.com)>
PLEASE HELP IF ANYONE HAS EXPERIENCE WITH THIS
I have a mark III classic w 912 uls Acting odd during taxi needs lots of left rudder to keep on the runway with tail on and off the ground and while flying needs lots of right stick to keep plane level. If you let go of the controls during straight and level flight the plane wants to roll to the left has anyone had similar experiences and or has anybody had any luck with adjusting engine mounts changing the thrust angle to help with aileron trim etc
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=470012#470012
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_________________ The smallest miracle right in front of you is enough to make you happy.... |
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byoungplumbing(at)gmail.c Guest
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Posted: Tue Jun 13, 2017 5:48 am Post subject: Strange Flying characteristics of new to me Mark III clasic |
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Kolbers,,,,,, I remember a few years back that someone mentioned that they trimmed a Kolb by adjusting the thrust line of the engine by raising or lowering the front or back of the motor mounts. I haven't found the correct search term to find it in the archives.. Is there anyone that is still on the list who can shed some light?
Boyd mkiii Utah
On Jun 12, 2017 2:34 PM, "jonealjr" <jonealjr(at)gmail.com (jonealjr(at)gmail.com)> wrote: Quote: | --> Kolb-List message posted by: "jonealjr" <jonealjr(at)gmail.com (jonealjr(at)gmail.com)>
PLEASE HELP IF ANYONE HAS EXPERIENCE WITH THIS
I have a mark III classic w 912 uls Acting odd during taxi needs lots of left rudder to keep on the runway with tail on and off the ground and while flying needs lots of right stick to keep plane level. If you let go of the controls during straight and level flight the plane wants to roll to the left has anyone had similar experiences and or has anybody had any luck with adjusting engine mounts changing the thrust angle to help with aileron trim etc
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=470012#470012
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Ralph B
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Joined: 14 Apr 2007 Posts: 367 Location: Mound Minnesota
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Posted: Tue Jun 13, 2017 7:18 am Post subject: Re: Strange Flying characteristics of new to me Mark III cla |
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Here are pictures of the Kolbra U-joint adjust for roll control. Put washers in on top or bottom for whichever the way you want to correct the roll.
Ralph B
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_________________ Ralph B
Kolb Kolbra 912uls
N20386
550 hours
Last edited by Ralph B on Thu Jun 15, 2017 6:35 am; edited 3 times in total |
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stuart(at)harnerfarm.net Guest
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Posted: Tue Jun 13, 2017 7:18 am Post subject: Strange Flying characteristics of new to me Mark III clasic |
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Jack Hart has a lot of info about this on a Firefly.
http://jackbhart.com/firefly/firefly56.html
From: owner-kolb-list-server(at)matronics.com [mailto:owner-kolb-list-server(at)matronics.com] On Behalf Of B Young
Sent: Tuesday, June 13, 2017 8:49 AM
To: Kolb List
Subject: Re: Strange Flying characteristics of new to me Mark III clasic
Kolbers,,,,,, I remember a few years back that someone mentioned that they trimmed a Kolb by adjusting the thrust line of the engine by raising or lowering the front or back of the motor mounts. I haven't found the correct search term to find it in the archives... Is there anyone that is still on the list who can shed some light?
Boyd mkiii Utah
On Jun 12, 2017 2:34 PM, "jonealjr" <jonealjr(at)gmail.com (jonealjr(at)gmail.com)> wrote:
--> Kolb-List message posted by: "jonealjr" <jonealjr(at)gmail.com (jonealjr(at)gmail.com)>
PLEASE HELP IF ANYONE HAS EXPERIENCE WITH THIS
I have a mark III classic w 912 uls Acting odd during taxi needs lots of left rudder to keep on the runway with tail on and off the ground and while flying needs lots of right stick to keep plane level. If you let go of the controls during straight and level flight the plane wants to roll to the left has anyone had similar experiences and or has anybody had any luck with adjusting engine mounts changing the thrust angle to help with aileron trim etc
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=470012#470012
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rel="noreferrer" target="_blank">http://www.matronics.com/contribution
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byoungplumbing(at)gmail.c Guest
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Posted: Tue Jun 13, 2017 9:04 am Post subject: Strange Flying characteristics of new to me Mark III clasic |
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Stewart, thanks, that link was exactly what I was looking for...
Boyd Young
Do not archive.
On Jun 13, 2017 9:21 AM, "Stuart Harner" <stuart(at)harnerfarm.net (stuart(at)harnerfarm.net)> wrote: Quote: |
Jack Hart has a lot of info about this on a Firefly.
http://jackbhart.com/firefly/firefly56.html
From: owner-kolb-list-server(at)matronics.com (owner-kolb-list-server(at)matronics.com) [mailto:owner-kolb-list-server(at)matronics.com (owner-kolb-list-server(at)matronics.com)] On Behalf Of B Young
Sent: Tuesday, June 13, 2017 8:49 AM
To: Kolb List
Subject: Re: Strange Flying characteristics of new to me Mark III clasic
Kolbers,,,,,, I remember a few years back that someone mentioned that they trimmed a Kolb by adjusting the thrust line of the engine by raising or lowering the front or back of the motor mounts. I haven't found the correct search term to find it in the archives... Is there anyone that is still on the list who can shed some light?
Boyd mkiii Utah
On Jun 12, 2017 2:34 PM, "jonealjr" <jonealjr(at)gmail.com (jonealjr(at)gmail.com)> wrote:
--> Kolb-List message posted by: "jonealjr" <jonealjr(at)gmail.com (jonealjr(at)gmail.com)>
PLEASE HELP IF ANYONE HAS EXPERIENCE WITH THIS
I have a mark III classic w 912 uls Acting odd during taxi needs lots of left rudder to keep on the runway with tail on and off the ground and while flying needs lots of right stick to keep plane level. If you let go of the controls during straight and level flight the plane wants to roll to the left has anyone had similar experiences and or has anybody had any luck with adjusting engine mounts changing the thrust angle to help with aileron trim etc
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=470012#470012
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errer" target="_blank">http://wiki.matronics.com
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Ralph B
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Joined: 14 Apr 2007 Posts: 367 Location: Mound Minnesota
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Posted: Tue Jun 13, 2017 11:55 am Post subject: Re: Strange Flying characteristics of new to me Mark III cla |
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Along with the U-joints, there is also the offset fin. This was installed by the builder and I don't see how I would do without it. I've also included a picture of the adjustable rudder trim tab. Between the U-joints, offset fin, and rudder trim tab, the Kolbra can fly hands off in calm air. For pitch trim, the builder installed a motorized bungee windup to move the stick forward or aft. It is controlled with a toggle switch for nose up or down trim.
Ralph B
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_________________ Ralph B
Kolb Kolbra 912uls
N20386
550 hours
Last edited by Ralph B on Wed Jun 14, 2017 9:59 am; edited 1 time in total |
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neilsenrm(at)gmail.com Guest
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Posted: Tue Jun 13, 2017 6:40 pm Post subject: Strange Flying characteristics of new to me Mark III clasic |
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Jimmy
We don't know your airplane so we can only guess what maybe the problem. You have our best suggestions..... Maybe it isn't the airplane?
Bill may have some good suggestions but do not follow the 5 foot suggestion. Our Kolbs do not react well in this maneuver. I can't think of a better way to bend a perfectly good Kolb.
Rick Neilsen
Redrive VW Powered MKIIIC
On Tue, Jun 13, 2017 at 7:18 PM, Bill Berle <victorbravo(at)sbcglobal.net (victorbravo(at)sbcglobal.net)> wrote:
Quote: | --> Kolb-List message posted by: Bill Berle <victorbravo(at)sbcglobal.net (victorbravo(at)sbcglobal.net)>
Jimmy I am posting things on the Kolb e-mail list, but nobody seems to have a direct answer for why the airplane rolls one way and not another.
I have three separate ideas for you to try, but I have not tested any of them.
First, Use a digital level, measuring at three or four places on each wing, to make sure your airplane is not warped or built improperly. If one wing is twisted only a few degrees, it will answer half of these problems immediately. Tape or clamp the level onto a piece of aluminum angle or a straight edge that is 100% straight. Jack up the tailwheel until the airplane is level by their definition. Measure at the root rib on each side, two ribs on each wing in the middle, and the last tip rib. You are checking to see that ALL of these lines are exactly the same.
Second, make 100% sure your airplane is rigged and adjusted to the factory specs. Get this information from Bryan Melbourne if you don't already have it. Basically, forget about anything that anyone else has done, and "zero out" the settings to whatever Kolb says they are supposed to be.
Third, make a piece of tube or dowel that fits into or onto the control stick, that allows you to have another 6 or 8 inches of leverage. This can be temporary, but you definitely need to have more control avaiilable than you need to use.
Fourth, actually measure and record how much each aileron twists when you move the stick and someone holds the tip of the aileron. What you are looking for is one aileron being more flexible than the other, or one aileron having something loose or cracked, etc.
At that time, after you have proven the wings are not twisted, and all four control surfaces are where the factory says they should be,a nd nothing is weak or cracked... THEN go test fly the aircraft again. Test it on the main runway, before the control tower opens. Do short flights at 5 foot altitude, verify that the airplane flies straight and that you have no "pull" or roll to the right or left. You MUST prove to yourself (and your kids) that you have plenty of aileron control authority to roll right and left equally, BEFORE you let yourself get above 5 feet.
Bill Berle
www.ezflaphandle.com - safety & performance upgrade for light aircraft
www.grantstar.net - winning proposals for non-profit and for-profit entities
--------------------------------------------
On Mon, 6/12/17, jonealjr <jonealjr(at)gmail.com (jonealjr(at)gmail.com)> wrote:
Subject: Strange Flying characteristics of new to me Mark III clasic
To: kolb-list(at)matronics.com (kolb-list(at)matronics.com)
Date: Monday, June 12, 2017, 1:31 PM
--> Kolb-List message posted by:
"jonealjr" <jonealjr(at)gmail.com (jonealjr(at)gmail.com)>
PLEASE HELP IF ANYONE HAS EXPERIENCE
WITH THIS
I have a mark III classic w 912 uls
Acting odd during taxi needs lots of left rudder to keep on
the runway with tail on and off the ground and while flying
needs lots of right stick to keep plane level. If you let go
of the controls during straight and level flight the plane
wants to roll to the left has anyone had similar experiences
and or has anybody had any luck with adjusting engine mounts
changing the thrust angle to help with aileron trim etc
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=470012#470012
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Richard Pike
![](images/avatars/57903806352d56370bc2be.jpg)
Joined: 09 Jan 2006 Posts: 1670 Location: Blountville, Tennessee
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Posted: Tue Jun 13, 2017 6:46 pm Post subject: Re: Strange Flying characteristics of new to me Mark III cla |
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https://microsoft-powertoys-image-resizer.en.softonic.com/
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_________________ Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0
Forgiving is tough, being forgiven is wonderful, and God's grace really is amazing. |
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Ralph B
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Joined: 14 Apr 2007 Posts: 367 Location: Mound Minnesota
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Posted: Wed Jun 14, 2017 10:05 am Post subject: Re: Strange Flying characteristics of new to me Mark III cla |
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Richard Pike wrote: | https://microsoft-powertoys-image-resizer.en.softonic.com/ |
Richard, I scaled down the images by 50%. It works much better!
Ralph B
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_________________ Ralph B
Kolb Kolbra 912uls
N20386
550 hours |
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Ralph B
![](images/avatars/67364827497a6bd2569cc.jpg)
Joined: 14 Apr 2007 Posts: 367 Location: Mound Minnesota
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Posted: Thu Jun 15, 2017 5:58 am Post subject: Re: Strange Flying characteristics of new to me Mark III cla |
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I failed to mention the Kolbra fin offset was built that way due to the powerful 912 engine that spins in the opposite direction of a 2-stroke engine. From the rear of the airplane, it spins in a counterclockwise direction whereas a 2-stroke will spin in a clockwise direction. This makes a difference in how the airplane is trimmed out. When I upgraded to the 912uls 100hp engine, I was very happy to have that offset built in as the rudder trim tab would not have been able to hold it without using constant rudder on the pedals. Even then, the airplane would have been flying in a constant yawed condition which I didn't like. On takeoff, I use right rudder to counteract P-factor. If the Kolbra had a 2-stroke engine, it would be the opposite left rudder like in a Firestar. May I also say that wind conditions can fool you when making adjustments. On the ground, a crosswind or heavy tailwind can make the airplane difficult to maneuver. Even in the air, a good crosswind will make you hold right or left stick sometimes, so I would say to make all your trim adjustments in calm air conditions.
The original post said his airplane rolled to the left and needed right stick to counteract the roll. If the airplane is rigged properly, this happens due to the torque of the 912 engine and why the fin offset was built into my Kolbra. The same will happen for a Mark III with a 912 engine. This problem has been discussed before and a rudder trim tab will correct some of the problem, but I think the real solution is the offset fin as seen in the above pictures.
Ralph B
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_________________ Ralph B
Kolb Kolbra 912uls
N20386
550 hours
Last edited by Ralph B on Thu Jun 15, 2017 7:06 am; edited 1 time in total |
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John Hauck
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Joined: 09 Jan 2006 Posts: 4639 Location: Titus, Alabama (hauck's holler)
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Posted: Thu Jun 15, 2017 6:55 am Post subject: Strange Flying characteristics of new to me Mark III clasic |
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Don't want to contradict Ralph B, but I have a little different take on the
upper vertical stabilizer leading edge offset.
I tried for a very long time to get Old Kolb Aircraft to experiment with
offsetting the leading edge of the upper vertical stabilizer on the factory
MKIII because I had an idea that this would help remedy the adverse yaw
problem. However, they never did.
At that time I was flying with a rudder trim tab half the length of what I
finally discovered solved the yaw problem.
The reason I didn't want to experiment on my MKIII was because I didn't want
to drill a bunch of holes and screw up my airplane. I had already made a
17,200 mile flight with the slip/skid ball yawed a half ball out, and got
tired of looking at it. My MKIII flew great this way, but it just wasn't
right.
I started out by offsetting the leading edge by 1/2". No observable change.
Drilled out the SS rivets and tried 1". Very slight change. Finally I got
it pushed over to 1.5" with hardly any difference. Not worth all the
effort. On the down side, doing it my way was actually twisting the tail
post and bending the leading edge tube of the upper vertical stabilizer
which eventually failed. Big job repairing this. When I did I went back to
centering the upper vertical stabilizer the way it should be.
Then I decided to experiment with the rudder trim tab. I chose to go big
and built the first one three rib bays long. Wow! That was an overkill.
Since I had attached with duct tape, I snatched it off, cut off a third (one
rib bay), stuck it back on and discovered it was perfect. Slip/skid ball
centered with my feet on the deck.
I think Mark German modified the tail post on his Kolbra after he saw mine
and talked with me. Cannot remember for sure.
There is no need to offset the upper vertical stabilizer because an adequate
rudder trim tab solves the yaw problem. A much simpler and effective
solution.
Direction of prop rotation and HP did not make much difference to the yaw
problem. I had it with 65, 80, and 100 hp on my MKIII.
John h
mkIII
Fayetteville, NC
I failed to mention the Kolbra fin offset was built that way due to the
powerful 912 engine that spins in the opposite direction of a 2-stroke
engine. From the rear of the airplane, it spins in a counterclockwise
direction whereas a 2-stroke will spin in a clockwise direction. This makes
a difference in how the airplane is trimmed out. When I upgraded to the
912uls 100hp engine, I was very happy have that offset built in as the
rudder trim tab would not have been able to hold it without using constant
rudder on the pedals. Even then, the airplane would have been flying in a
constant yawed condition which I didn't like.
Ralph B
--------
Ralph B
Kolb Kolbra 912uls
N20386
550 hours
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=470154#470154
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_________________ John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama |
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Ralph B
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Joined: 14 Apr 2007 Posts: 367 Location: Mound Minnesota
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Posted: Thu Jun 15, 2017 7:20 am Post subject: Re: Strange Flying characteristics of new to me Mark III cla |
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John,
While in flight do you have to hold any rudder at all or are your feet neutral on the pedals with the ball centered? Just wondering ...
The reason I say this is if you have to hold any rudder, then your trim tab is not working and your leg would get tired.
I believe Mark German did consult with you and others before offsetting the fin like that. He didn't want to drill out extra holes in the tube, if he didn't have to.
As it stands, with my 100hp 912, the only way to keep it from rolling was the offset fin. If I didn't have that, I would probably need a very large trim tab as you have.
I think whether it's an offset fin or rudder tab, it's accomplishing the same purpose except the rudder tab will push (or pull) on one pedal more than the other so they aren't neutral while in flight. That in itself would bug the hell out of me, but then that's just me.
Ralph B
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_________________ Ralph B
Kolb Kolbra 912uls
N20386
550 hours |
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John Hauck
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Joined: 09 Jan 2006 Posts: 4639 Location: Titus, Alabama (hauck's holler)
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Posted: Thu Jun 15, 2017 2:25 pm Post subject: Strange Flying characteristics of new to me Mark III clasic |
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Yes sir, I fly can with my feet off the pedals and on the deck with centered
slip/skid ball, as I indicated in my original comment.
John h
mkIII
Fayetteville, NC
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_________________ John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama |
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jonealjr
Joined: 10 Feb 2017 Posts: 23
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Posted: Sun Jun 18, 2017 8:47 pm Post subject: Re: Strange Flying characteristics of new to me Mark III cla |
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Than you everyone for ALL the input
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