 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
williamtsullivan(at)att.n
Guest
|
 Posted: Fri Dec 09, 2011 7:13 pm Post subject: Perplexed turns to Bummed |
 |
|
Rick- I just had an odd thought, but I don't know if it would help. By any chance, the last time the plane was folded did the wing struts get swiched side to side? My Firestar came through with two sets of struts, and they weren't marked. They are slightly different in length, and if it got by unnoticed it might do something. Stranger things have happened. When I found out which was which, I marked them.
Bill Sullivan
Windsor Locks, Ct.
--- On Fri, 12/9/11, Richard Girard <aslsa.rng(at)gmail.com> wrote:
| Quote: |
From: Richard Girard <aslsa.rng(at)gmail.com>
Subject: Perplexed turns to Bummed
To: kolb-list(at)matronics.com
Date: Friday, December 9, 2011, 9:44 PM
I flipped the motor mount over and had high hopes that I would at least get some response in changing the right yaw, and take some of the pressure off my poor beleaguered left leg. No such luck, no improvement whatsoever, so the straight motor mount and the big trim tab have to go back on. Maybe with the yaw string, I'll be able to keep it trimmed up (no pun intended) and do a nice Kolb like approach stall. We'll see. One thing the yaw string has done is make it much easier to keep the airplane flying as it should. Yesterday I finally had confidence enough to try a full flap landing. I had forgotten just how much I missed doing them. It is just so sweet to bring a Kolb in on three and grease it on. Its one of the Kolb MkIII's (C or X) endearing qualities. So, I'll keep on trying to get Ken a nice safe airplane and hang on to that last landing to keep my spirits up while I'm at it.
Rick Girard
--
Zulu Delta
Mk IIIC
Thanks, Homer GBYM
It isn't necessary to have relatives in Kansas City in order to be unhappy.
- Groucho Marx
| Quote: | http://www.matronics.com/conhref="http://www.matronics.com/Navigator?Kolb-List">http://www.matronics.========================
" target="_blank" href="http://forums.matronics.com">http://forums.matr --> |
|
[quote][b]
| | - The Matronics Kolb-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?Kolb-List |
|
|
|
| Back to top |
|
 |
John Hauck
Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)
|
| Posted: Fri Dec 09, 2011 8:15 pm Post subject: Perplexed turns to Bummed |
|
|
I flipped the motor mount over and had high hopes that I would at least get some response in changing the right yaw, and take some of the pressure off my poor beleaguered left leg. No such luck, no improvement whatsoever
Rick Girard
[quote] I believe the long, wide nose pod on the Xtra adversely affects yaw when not kept exactly in yaw trim. john hmkIIITitus, Alabama [b]
| | - The Matronics Kolb-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?Kolb-List |
|
_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama |
|
| Back to top |
|
|
Dana
Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA
|
| Posted: Sat Dec 10, 2011 4:55 am Post subject: Perplexed turns to Bummed |
|
|
Angling the thrust line will do little on a pusher like a Kolb, because the engine is so close to the center of the aircraft.
One thing that will affect yaw trim is if the wing and stabilizer aren't level with respect to each other. If, for example, the left side of the stabilizer is too high, the aircraft will tend to yaw to the right, and vice versa. The solution may be as simple as adjusting your tail wires. Unequal length wing struts will cause this, if they're on the wrong side. If the right strut is longer than the left, it's the same effect (the left side of the stabilizer will be high relative to the wings) I got some noticeable improvement in yaw trim on my US when I swapped the struts.
If course, even if your tail is straight, adjusting the tail wires (so it's not straight) might fix your yaw problem.
On the first successful human powered airplane (the Gossamer Condor), tilting the stabilizer was actually the primary yaw control, since it caused less drag than moving the rudder.
-Dana
At 11:12 PM 12/9/2011, John Hauck wrote:
| Quote: | I flipped the motor mount over and had high hopes that I would at least get some response in changing the right yaw, and take some of the pressure off my poor beleaguered left leg. No such luck, no improvement whatsoever
Rick Girard
| Quote: | I believe the long, wide nose pod
on the Xtra adversely affects yaw when not kept exactly in yaw
trim. |
|
--
Blow your mind, smoke gunpowder.
[quote][b]
| | - The Matronics Kolb-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?Kolb-List |
|
|
|
| Back to top |
|
|
Frankd
Joined: 28 Mar 2008
Posts: 64
|
| Posted: Sat Dec 10, 2011 9:04 am Post subject: Re: Perplexed turns to Bummed |
|
|
Hi Rick/Kolbers,
On Tuesday I attached a rudder trim tab , per John H's specifications, to get rid of the need for right rudder input in cruise flight and take-off.
2 things.
a/ I had guessed at the angle and had too much in, so when I flew I had to apply LEFT rudder to keep the string centered. Landed, unbent the tab a little and next flight was good with my feet off the pedals.
b/ I did not measure the actual rib spacing on my rudder, just looked up the plans that specified 7 inches between the ribs.. So 14 3/4 inches in length should have been Ok.. NOT. For some reason I spaced my ribs at 7 1/2 inches apart, so the trim tab did not fully span two ribs bays. It still worked wonderfully as I attached it to the Trailing edge as well, but its something to watch for.
My engine thrust line is right on the centerline. I cannot mess with that.
From the post I would recheck all angles of incidence of each wing to each other and each Horizontal stab to each other. Having cramps in your left foot sounds just wrong.. I believe something may not be aligned right.
I still have a tad of roll to the right ,but its very minor, which I'm going to adjust with bungees to the stick, at first.
I also think that the big nose pod on the Xtra has an effect on fore and aft trim. I find I need to constantly adjust elevator to keep straight and level, I cannot fly hands off for very long before it dives or climbs. But thats fine, I like to fly. Its not a big issue.
I also wrapped some tinfoil around part of the sparkplug wires on my Jabiru to see if the radio noise was reduced. It did seem to work some. So now I'm going to get some stainless steel braided sleeving and completely cover all the ignition wires with that (with tinfoil inside) to see if my radio reception improves. At full power I cannot hear anything clearly, I have to reduce to about 2000 rpm to hear the traffic.
I will keep posting my results on these issues but if I see any funny cat pictures I may throw those in for fun. 
My 2 cents
FrankD
M3X, N1014S, 8 hrs logged
Hollister, Ca
| | - The Matronics Kolb-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?Kolb-List |
|
|
|
| Back to top |
|
|
Richard Pike
Joined: 09 Jan 2006
Posts: 1671
Location: Blountville, Tennessee
|
| Posted: Sat Dec 10, 2011 12:36 pm Post subject: Re: Perplexed turns to Bummed |
|
|
| Frankd wrote: | Hi Rick/Kolbers,
<snip>
I also wrapped some tinfoil around part of the sparkplug wires on my Jabiru to see if the radio noise was reduced. It did seem to work some. So now I'm going to get some stainless steel braided sleeving and completely cover all the ignition wires with that (with tinfoil inside) to see if my radio reception improves. At full power I cannot hear anything clearly, I have to reduce to about 2000 rpm to hear the traffic.
<snip>
FrankD
M3X, N1014S, 8 hrs logged
Hollister, Ca |
Where is your antenna located?
| | - The Matronics Kolb-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?Kolb-List |
|
_________________
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0
Forgiving is tough, being forgiven is wonderful, and God's grace really is amazing. |
|
| Back to top |
|
|
ceengland(at)bellsouth.ne
Guest
|
| Posted: Sat Dec 10, 2011 2:21 pm Post subject: Perplexed turns to Bummed |
|
|
For a baseline, what does it do if you climb to altitude & pull power to idle, & allow the plane to maintain airspeed? (I mean in terms of yaw/roll; not decent rate...)
How does that compare to power off to other similar models in the same idle-power conditions?
I have no experience with Kolbs, but I do know that for RV-x's (they are both airplanes, right?), testing involves checking incidence of each wing, how the gear leg fairings are installed (can have as much effect as the rudder), even how sharp the trailing edges of the aluminum ailerons are folded; all have major effects on the yaw/roll characteristics. The RV's have significant vertical stab offset built into the design, & most still need a trim tab on the rudder.
Anyway, the reason for the question is to figure out whether you have problem with engine installation or an airframe alignment issue.
Charlie
On 12/10/2011 11:28 AM, Richard Girard wrote: [quote]Bill, Dana, yes the OB made the struts different lengths. They are marked and on the correct side (on is 1/2" longer than the other and it's obvious if you get them wrong. I did it deliberately once so I could see it for myself. One wing is flat, no dihedral at all, the other is cranked way up. As I told Mike Welch, the tail wires are new, made by me, and as precise as I could make them, to the point that they are interchangeable side to side and they twang when plucked.
I long ago fixed the OB's poor installation of the horizontal stabilizer brackets. The attached pictures show how they were when I got the airplane and how they are now (although the HS's are in the bottom holes of the brackets now).
Dana, When I put the offset motor mount on with the motor twisted to the left and the thrust center offset about an inch, it DOUBLED the amount of yaw to the right.
Rick
On Sat, Dec 10, 2011 at 6:41 AM, Dana Hague <d-m-hague(at)comcast.net (d-m-hague(at)comcast.net)> wrote:
| Quote: | Angling the thrust line will do little on a pusher like a Kolb, because the engine is so close to the center of the aircraft.
One thing that will affect yaw trim is if the wing and stabilizer aren't level with respect to each other. If, for example, the left side of the stabilizer is too high, the aircraft will tend to yaw to the right, and vice versa. The solution may be as simple as adjusting your tail wires. Unequal length wing struts will cause this, if they're on the wrong side. If the right strut is longer than the left, it's the same effect (the left side of the stabilizer will be high relative to the wings) I got some noticeable improvement in yaw trim on my US when I swapped the struts.
If course, even if your tail is straight, adjusting the tail wires (so it's not straight) might fix your yaw problem.
On the first successful human powered airplane (the Gossamer Condor), tilting the stabilizer was actually the primary yaw control, since it caused less drag than moving the rudder.
-Dana
At 11:12 PM 12/9/2011, John Hauck wrote:
| Quote: | I flipped the motor mount over and had high hopes that I would at least get some response in changing the right yaw, and take some of the pressure off my poor beleaguered left leg. No such luck, no improvement whatsoever
Rick Girard
| Quote: | I believe the long, wide nose pod
on the Xtra adversely affects yaw when not kept exactly in yaw
trim. |
| Quote: | john
hmkIIITitus,
Alabama |
|
|
[b]
| | - The Matronics Kolb-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?Kolb-List |
|
|
|
| Back to top |
|
|
John Hauck
Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)
|
| Posted: Sat Dec 10, 2011 2:55 pm Post subject: Perplexed turns to Bummed |
|
|
Anyway, the reason for the question is to figure out whether you have problem with engine installation or an airframe alignment issue.
Charlie
Charlie E/Gang:
I believe an RV is a tractor and a Kolb is a pusher. Both fly much the same with the engine off, but bring in the power and they are two different animals.
In my limited experience with Kolbs, trim problems are caused by prop wash and a high thrust line. When I pull off the power of my mkIII, I don't need forced trim or trim tabs to trim up perfectly. But, when I bring the power back up to cruise, I do.
The addition of a very long flat nose to the MKIII, to call it a MKIIIx, created a lot of problems. Not only does relative wind grab the nose when it gets out of yaw trim, it also changes relative wind over the tail section.
Brother Jim designed and fabricated adjustable brackets for the leading edge of the horizontal stabilizers on my MKIII when we were building it in 1991. My intended purpose for these brackets was to be able to reduce nose down pitching forces caused by the high thrust line. During experimentation I discovered a sweet spot when the center hole of the bracket is used. That is where the leading edge stays, primarily because that is where my MKIII settles down in pitch at cruise power. If I go up or down a hole, flying at cruise is much like trying to balance on a ball. The MKIII wants to fall off the back side or pitch over on its nose. Center hole, she settles down in cruise attitude.
Kolb aircraft are happy whether rigged perfectly, if there is such a thing, or not rigged so perfectly. The sheer number of Kolbs happily flying around all over the world is testament to that fact. I think I flew my MKIII half a ball out of yaw trim for the first 8 or 10 years. That included some very long cross country flights and a couple thousand hours. Finally came up with a trim tab that worked, keeping the ball centered. Could I tell the difference in the way my MKIII flew? Don't think so.
john h
mkIII
Titus, Alabama[quote] [b]
| | - The Matronics Kolb-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?Kolb-List |
|
_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama |
|
| Back to top |
|
|
byoungplumbing(at)gmail.c
Guest
|
| Posted: Sat Dec 10, 2011 3:02 pm Post subject: Perplexed turns to Bummed |
|
|
For a baseline, what does it do if you climb to altitude & pull power to idle, & allow the plane to maintain airspeed? (I mean in terms of yaw/roll; not decent rate...)
I have no experience with Kolbs, but I do know that for RV-x's (they are both airplanes, right?),
Anyway, the reason for the question is to figure out whether you have problem with engine installation or an airframe alignment issue.
Charlie
Charlie
with the 912 on my mkiii I need right rudder in powered flight.. when pulled to idle and up to speed, I need a small amount of left rudder.
the difference is the way the air swirls off the prop when it is being driven, or the swirling air changes direction when the plane is at idle and the air is wind milling the prop. it seems to me if I make an approach at 3200 rpm, plus or minus,,, no rudder input is necessary.
yes the kolbs and rv's are both airplanes,,, but in a design standpoint,,, the rv's,, the ones I know of all use an engine that turns clockwise when looking from the back. so trim issues can be built into the design, also the rv's are tractor, and the long fuselage can help straighten the prop blast so it has less affect on the tail, than the kolbs do because of the short open distance between the prop and tail. the other factor is that some kolbs are built with 2 strokes, clockwise when looking from the rear, and the 912 series, that turns counter clock in the pusher configuration. so modifying the airframe would be dependent on the engine used, by building things straight, the mod needed is the rudder trim, left or right depending on the engine used.
I hope this made sense, my mind was clear when my fingers started on the keyboard. and because my mind works faster than my fingers,,, sometimes what comes out is less clear than I would like.
yes they are both airplanes,, comparing to fruit,,, they are both fruit but the apple and orange differences are still present.
boyd young
mkiii utah
[quote][b]
| | - The Matronics Kolb-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?Kolb-List |
|
|
|
| Back to top |
|
|
ceengland(at)bellsouth.ne
Guest
|
| Posted: Sat Dec 10, 2011 3:16 pm Post subject: Perplexed turns to Bummed |
|
|
On 12/10/2011 04:52 PM, John Hauck wrote: | Quote: | 1024x768 <![endif]--> false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 <![endif]--> <![endif]--> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";} <![endif]--> <![endif]--> <![endif]-->
Anyway, the reason for the question is to figure out whether you have problem with engine installation or an airframe alignment issue.
Charlie
Charlie E/Gang:
I believe an RV is a tractor and a Kolb is a pusher. Both fly much the same with the engine off, but bring in the power and they are two different animals.
In my limited experience with Kolbs, trim problems are caused by prop wash and a high thrust line. When I pull off the power of my mkIII, I don't need forced trim or trim tabs to trim up perfectly. But, when I bring the power back up to cruise, I do.
The addition of a very long flat nose to the MKIII, to call it a MKIIIx, created a lot of problems. Not only does relative wind grab the nose when it gets out of yaw trim, it also changes relative wind over the tail section.
Brother Jim designed and fabricated adjustable brackets for the leading edge of the horizontal stabilizers on my MKIII when we were building it in 1991. My intended purpose for these brackets was to be able to reduce nose down pitching forces caused by the high thrust line. During experimentation I discovered a sweet spot when the center hole of the bracket is used. That is where the leading edge stays, primarily because that is where my MKIII settles down in pitch at cruise power. If I go up or down a hole, flying at cruise is much like trying to balance on a ball. The MKIII wants to fall off the back side or pitch over on its nose. Center hole, she settles down in cruise attitude.
Kolb aircraft are happy whether rigged perfectly, if there is such a thing, or not rigged so perfectly. The sheer number of Kolbs happily flying around all over the world is testament to that fact. I think I flew my MKIII half a ball out of yaw trim for the first 8 or 10 years. That included some very long cross country flights and a couple thousand hours. Finally came up with a trim tab that worked, keeping the ball centered. Could I tell the difference in the way my MKIII flew? Don't think so.
john h
mkIII
Titus, Alabama
|
We could probably split hairs on what's a real 'pusher', when it comes to flying characteristics. The vertical stab is still in the prop wash on a Kolb, right?
His problems seem more related to yaw/roll than pitchover.
The point of my question is to ask whether that particular airframe flies differently from other airframes of the same model. It seems obvious, at least to Rick, that it's power-on cruise performance is quite different from what others are experiencing. So that begs the question:
Is it engine installation related, or is it airframe alignment related?
I haven't followed every single post in this thread; is Rick flying the same or similar motor as typical for this airframe design, and does the prop turn the same direction, and is the diameter significantly larger or smaller than typical for this design? Any or all of the above would have an effect.
Charlie
[quote][b]
| | - The Matronics Kolb-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?Kolb-List |
|
|
|
| Back to top |
|
|
zeprep251(at)aol.com
Guest
|
| Posted: Sun Dec 11, 2011 7:33 am Post subject: Perplexed turns to Bummed |
|
|
Frank,
Bought some ferrite chokes at Radio shack and snapped them on at different places on the antenna coax.This seems to have helped get the ignition noise out of the radio,Will try some chokes on the ignition wires going to the switch next.Let you know if it helps any.
G.Aman MK3C Jabiru 2200A
--
| | - The Matronics Kolb-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?Kolb-List |
|
|
|
| Back to top |
|
|
Frankd
Joined: 28 Mar 2008
Posts: 64
|
| Posted: Mon Dec 12, 2011 9:20 am Post subject: Re: Perplexed turns to Bummed - Radio noise |
|
|
Hi Gary/Rick,
I have attached a choke to the antenna coax. My antenna is mounted inside the nose cone and the coax runs about two feet back to the built-in radio. That may have helped. Tkx I think I'll attach more.
I am trying ALL suggestions to reduce radio noise, as I like to hear traffic and control towers,
a/ Ferrite chokes on the Antenna. Antenna in nose cone (Shortest route to radio)
b/ Reduced the wiring to the headset plugs, Used shielded wiring.
c/ Am covering the sparkplug leads to shield them.
d/ I have not yet directly attached the Radio positive and neg to the battery but I have attached ferrite chokes along the power cable.
e/ I am using a Noise cancelling headset but earbuds may also help.
Any other suggestions??
Always learning
FrankD
N1014S, M3X
| | - The Matronics Kolb-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?Kolb-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
