Matronics Email Lists Forum Index Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
 
 Get Email Distribution Too!Get Email Distribution Too!    FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Thrustline again.

 
Post new topic   Reply to topic    Matronics Email Lists Forum Index -> Kolb-List
View previous topic :: View next topic  
Author Message
phcpilot



Joined: 24 May 2016
Posts: 16

PostPosted: Tue Sep 28, 2021 4:47 am    Post subject: Thrustline again. Reply with quote

One last thought on this is that the 503 powered Kolb that I had flew just fine. And I would bet a 503 Beaver/Skywatch would be the same. But if I'm going to go wild with power, why not use some of that power to keep the trim inline and retain reasonable flight characteristics?

On Tue., Sep. 28, 2021, 2:40 a.m. Kolb-List Digest Server, <kolb-list(at)matronics.com (kolb-list(at)matronics.com)> wrote:

[quote]*

 ==================================================
   Online Versions of Today's List Digest Archive
 ==================================================

Today's complete Kolb-List Digest can also be found in either of the
two Web Links listed below.  The .html file includes the Digest formatted
in HTML for viewing with a web browser and features Hyperlinked Indexes
and Message Navigation.  The .txt file includes the plain ASCII version
of the Kolb-List Digest and can be viewed with a generic text editor
such as Notepad or with a web browser.

HTML Version:

    http://www.matronics.com/digest/digestview.php?Style=82701&View=html&Chapter=2021-09-27&Archive=Kolb

Text Version:

    http://www.matronics.com/digest/digestview.php?Style=82701&View=txt&Chapter=2021-09-27&Archive=Kolb


 ================================================
   EMail Version of Today's List Digest Archive
 ================================================


           ----------------------------------------------------------
                           Kolb-List Digest Archive
                                      ---
                     Total Messages Posted Mon 09/27/21: 0
           ----------------------------------------------------------


Today's Message Index:
----------------------


- 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
View user's profile Send private message
jhauck



Joined: 02 Jan 2020
Posts: 21

PostPosted: Tue Sep 28, 2021 5:48 am    Post subject: Thrustline again. Reply with quote

I don’t believe the flight characteristics of the Kolb aircraft are “unreasonable”. If they were, I wouldn’t have waster 36 years building and flying them.

I believe the thrust line Homer Kolb designed into the Kolb aircraft are optimum overall. Not being an engineer, but an avid experimenter, builder, and flyer, over the years, I’ve tried most of the tricks folks talk about experimenting with today.

Just guessing, and actually experimenting with my Kolbs, I tried changing the thrust line up and down, and left and right. This meant ruining a good set of engine mounts, but the only way I could be satisfied if I could make things better. After all was said and done, I always went back to Homer’s specs. Pitch attitude is easily controlled with horizontal stabilizer adjustments, trim tabs, and forced trim. ( My MKIII was the first to have adjustable leading edges of the horizontal stabilizers. Incorporated into my MKIII when my Brother Jim fabricated the airframe and components at the Kolb Factory in January 1991.)

My MKIII adjusted to fly level in flight at idle power or engine off. Nose up trim was required as power was increased. Pitch trimmed at cruise power, 5,000 to 5,400 rpm, did not have to be adjusted again until reduced power to land. Only nose up trim is required.

Back to difficulty in breaking ground at WOT with a 100 horse Rotax, that happened on my first takeoff. I believe caused by “muscle memory” from flying my MKIII with an 80 horse Rotax for many hours. Immediate reduction of power and she broke ground. Never had to think about that after the first takeoff. All other take offs were done at WOT. All it takes is a little more back stick for a little more power.

Forgot something. I normally always used full flaps, 40 degs, on landing. Drooping the flaps also required more nose up pitch trim.

Another factor that encourages nose down trim is drag created by everything that is hanging below the wings. On my MKIII, I had much longer gear legs, 8.00X6 tires.

Additionally, one must remember that power changes are going to affect pitch trim, something we have to live with.

I had fixed trim tabs on my original Firestar for pitch, roll, and yaw. I made them out of .016” aluminum. They were flexible enough to change with speed changes. My FS would climb, WOT, hands off. Power changes did not affect trim changes. Power on, nose came up. Power off, nose came down. I lucked out on this set up. My FS had no forced trim or inflight adjustable trim tabs.

My Ultrastar was trimmed up similarly. Climbed perfectly WOT with no or little trim changes. However, the thrust line was right in the small of my back which compensated for drag created by all the stuff hanging below the wing. Was a very capable and fun flying machine.

Good luck with your experimentation of power and thrust lines. Let us know how you make out. What one can do with these little airplanes is infinite and fun on top of that.

john h
Titus, AL
Kolb Pilot, Retired

From: owner-kolb-list-server(at)matronics.com [mailto:owner-kolb-list-server(at)matronics.com] On Behalf Of Peter Cowan
Sent: Tuesday, September 28, 2021 7:47 AM
To: kolb-list(at)matronics.com
Subject: Kolb-List: Thrustline again.

One last thought on this is that the 503 powered Kolb that I had flew just fine. And I would bet a 503 Beaver/Skywatch would be the same. But if I'm going to go wild with power, why not use some of that power to keep the trim inline and retain reasonable flight characteristics?


On Tue., Sep. 28, 2021, 2:40 a.m. Kolb-List Digest Server, <kolb-list(at)matronics.com (kolb-list(at)matronics.com)> wrote:
[quote]
*

==================================================
Online Versions of Today's List Digest Archive
==================================================

Today's complete Kolb-List Digest can also be found in either of the
two Web Links listed below. The .html file includes the Digest formatted
in HTML for viewing with a web browser and features Hyperlinked Indexes
and Message Navigation. The .txt file includes the plain ASCII version
of the Kolb-List Digest and can be viewed with a generic text editor
such as Notepad or with a web browser.

HTML Version:

http://www.matronics.com/digest/digestview.php?Style=82701&View=html&Chapter=2021-09-27&Archive=Kolb

Text Version:

http://www.matronics.com/digest/digestview.php?Style=82701&View=txt&Chapter=2021-09-27&Archive=Kolb


================================================
EMail Version of Today's List Digest Archive
================================================


----------------------------------------------------------
Kolb-List Digest Archive
---
Total Messages Posted Mon 09/27/21: 0
----------------------------------------------------------


Today's Message Index:
----------------------


- 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
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Matronics Email Lists Forum Index -> Kolb-List All times are GMT - 8 Hours
Page 1 of 1

 
Jump to:  
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