Today's Message Index:
----------------------
1. 01:11 AM - Re: Kolb Firestar Progress report (Bill Berle)
2. 01:14 AM - Re: FYI G rating on Firefly (Bill Berle)
3. 05:17 AM - Re: Kolb Firestar Progress report (Richard Pike)
4. 06:03 AM - Re: Re: Kolb Firestar Progress report (John Hauck)
5. 02:11 PM - Re: Kolb Firestar Progress report (Richard Pike)
6. 03:59 PM - Re: FYI G rating on Firefly (Charlie England)
7. 04:12 PM - Re: Re: Kolb Firestar Progress report (John Hauck)
8. 04:58 PM - Re: FYI G rating on Firefly (John Hauck)
9. 05:18 PM - Re: FYI G rating on Firefly (Bill Berle)
Message 1
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| Subject: | Re: Kolb Firestar Progress report |
Just came back from building 80% of the rudder.
Thank you Richard, I do understand that flutter can happen on control surfaces.
If it becomes necessary I will put a balance weight on but hopefully that will
not be necessary. The Cub, Taylorcraft, Champ, etc. have welded steel rudders
and elevators that are much more "out of balance", and their flutter speeds
are higher. My goal was to make the controls stiffer and more robust, which also
helps prevent flutter.
I will make a better analysis of how much weight gain there actually was; I believe
it will be very little. But the short version is that I used .032 triangular
gussets, about 1.5 inches long and wide at the leading and trailing edge intersections,
rather than riveting the "rib" tube directly to the leading and
trailing edge with one rivet. Using the gussets allowed me to use two rivets,
and not have to squash the small tube. Using the gussets at the trailing edge
also allowed me to have a far better attachment where the ribs go all the way
to the trailing edge, instead of joining the two rib tubes with only one rivet.
I also "curled" the gussets around the tubes to create less protrusion into the
fabric. This was more than cosmetic... it allows you to have the full, correct,
safe "edge distance" between the hole and the edge of the part. The stock Kolb
drawings have you building parts that simply do not meet the time-honored
"2D" minimum edge distance (AC 43-13 and many other references). I know that the
Kolb factory did not do this by mistake, they were trying to prevent the edges
of the gussets from protruding as much. But the price for this is that they
gave up a very long-standing safety margin that has been built into sheet metal
and rivet structures since the 1920's.
I believe that there will be something like 3-4 inches of etra 5/16 x .035 tube
for each "rib" station. There will also be the extra weight of the gussets, and
a handful of additional rivets. Definitely more material, but hopefully still
down in the "negligible" range.
I also made a cosmetic, strutcural and serodynamic improvement at the trailing
edge. To keep the trailing edge of the rudder as thin as possible, I flightly
offset the two "rib" tubes at the trailing edge so the ribs would be flush with
the trailing edge tube.
Bill Berle
www.ezflaphandle.com - safety & performance upgrade for light aircraft
www.grantstar.net - winning proposals for non-profit and for-profit entities
--------------------------------------------
On Sat, 5/7/16, Richard Neilsen <neilsenrm@gmail.com> wrote:
Subject: Re: Kolb-List: Kolb Firestar Progress report
To: kolb-list@matronics.com
Date: Saturday, May 7, 2016, 6:22 AM
Richard Neilsen <neilsenrm@gmail.com>
Bill
Control surfaces on Kolbs can flutter if made heavier than
designed.
Rick Neilsen
Redrive VW Powered MKIII
Sent from my iPhone
> On May 6, 2016, at 5:15 PM, Bill Berle <victorbravo@sbcglobal.net>
wrote:
>
>
> I was out last night working on the Firestar project,
and wanted to report my progress.
>
> As of this writing, I have completed two horizontal
stabilizers, and have completed just about everything on the
vertical fin assembly. The only thing left on that is to
drill the hole for the lower tail brace wire bolt, but I'm
sure this can wait until I have the tail installed on the
fuselage tube and can line everything up better.
>
> I started to lay out the rudder last night, cut the
main upright tube, and started laying out the gussets. After
looking closely at the standard rudder and elevator, I
decided to make a slight change in the method of attaching
the parts together. To make a slightly more robust and more
rigid set of controls I will be using the same style of thin
"tube and gusset" construction as the stabilizer. This will
allow two rivets at each intersection instead of one, and
provide a small triangular gusset to stiffen and brace the
intersection. The extra weight and "control surface balance"
will very likely be negligible.
>
> I had made a decision to not attempt to build a
showplane, and not attempt to make everything perfect. An
engineer friend of mine has a saying... "perfection is the
enemy of completion" :) So my efforts will be used to build
a safe, solid, but not show quality aircraft. Since this one
will be used as a dirt and sand airplane fairly often, any
extra effort on a shiny finish will have been wasted. This
whole thing may be left Stits silver anyway, to make dings,
repairs and bullhead thorn repairs easier.
>
> As an esoteric note, I just realized that the serial
number on my fuselage (F-1203) is different than the number
in the instruction manual I got (690-something). Can anyone
tell me if there were any changes to the manual that would
affect this? How can I verify that I have the latest and
most applicable instruction manual and/or plans?
>
>
> Bill Berle
> www.ezflaphandle.com - safety & performance
upgrade for light aircraft
> www.grantstar.net
- winning proposals for non-profit and
for-profit entities
>
> --------------------------------------------
> On Fri, 5/6/16, Bill Berle <victorbravo@sbcglobal.net>
wrote:
>
> Subject: Re: Kolb-List: Re: ground aerobatics...
> To: kolb-list@matronics.com
> Date: Friday, May 6, 2016, 11:16 AM
>
> Bill Berle <victorbravo@sbcglobal.net>
>
> By normal flight training standards, based on very old
> memories, a steep turn is one that uses a bank angle
> 45 degrees or higher. 60 degrees is considered the
"steep
> turn" benchmark when you do FAA private pilot training
(at
> least it was in the 1970's when we had real pilot
> training).
>
> A 60 degree banked level flight turn in calm air
results in
> exactly a 2G load on the airframe. I'm pretty sure that
the
> Kolb was designed to withstand far far more than 2G.
(if
> not, I have a Firestar kit for sale cheap).
>
> However, bank angle alone does not determine G forces.
A 60
> degree banked coordinated level flight turn will give
you
> 2G. But a "wingover" maneuver is not a level turn, and
most
> of the time the high bank angle comes at a time when
the
> airplane is "unloaded". So the reality is that the
wingover
> maneuver shown in the video could easily have been at
> ZERO-G. (I do zero-G wingovers all the time in an old
Cessna
> 172 and it puts zero stress on the airframe)
>
> You can do a simple "aileron roll" that puts no stress
> whatsoever on the airplane for 3/4 of the maneuver, and
only
> 1.3 or 1.4G on the airplane during the other 1/4 of
the
> maneuver. There is a very famous incident of a Boeing
test
> pilot named Tex Johnson doing a full 360 degree aileron
roll
> in the first prototype 707, with a bunch of news
reporters
> on board, and it didn't even ruffle anyone's hair on
board
> the airplane. You can find the video on youtube I'm
sure.
>
> The FAA definition of "Aerobatics" is an excursion
from
> level flight of more than 30 degrees of pitch and 60
degrees
> of bank. But "aerobatic" maneuvers can easily be done
that
> exceed these numbers without putting any abnormal
stress or
> loads on the airplane... and are in reality not
"dangerous"
> in any way. What gets dangerous is when the pilot
misjudges
> or mishandles the recovery from these maneuvers, and
can
> easily accidentally exceed the speed or G load limits
that
> the airframe can handle. THAT is the dangerous part,
and
> THAT is why any pilot with a brain in his head will
get
> aerobatic or "upset recovery" training before playing
around
> with these kinds of maneuvers.
>
> The Kolb was of course not designed for aerobatics. It
does
> not make any sense to do intentional aerobatics in a
Kolb.
> As mentioned by others, if you are going to go out and
do
> hard aerobatics on purpose then go rent a Citabria.
>
> Bill Berle
> www.ezflaphandle.com - safety & performance
upgrade
> for light aircraft
> www.grantstar.net
- winning proposals for
> non-profit and for-profit entities
>
> --------------------------------------------
> On Fri, 5/6/16, flywithme <constrjh@pldi.net>
> wrote:
>
> Subject: Kolb-List: Re: ground aerobatics...
> To: kolb-list@matronics.com
> Date: Friday, May 6, 2016, 9:48 AM
>
> "flywithme" <constrjh@pldi.net>
>
> i see in some posts reference to the first pilot
making a
> steep banking turn as being a dangerous maneuver
in a
> kolb.
> is this really such a dangerous maneuver
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=455928#455928
>
>
>
>
>
>
>
> Forum -
> - MATRONICS WEB FORUMS -
> MATRONICS LIST WIKI -
> List Contribution Web Site -
>
-Matt
> Dralle, List Admin.
>
>
>
>
>
> Forum -
> - MATRONICS WEB FORUMS -
> MATRONICS LIST WIKI -
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>
-Matt
> Dralle, List Admin.
>
>
>
>
>
>
>
>
Forum -
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MATRONICS LIST WIKI -
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Dralle, List Admin.
Message 2
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| Subject: | Re: FYI G rating on Firefly |
In keeping with a very long and well-understood tradition in aircraft design and
manufacture, there is an additional 50% FOS, or "factor of safety". This means
that the airplane was likely tested to +6G
Bill Berle
www.ezflaphandle.com - safety & performance upgrade for light aircraft
www.grantstar.net - winning proposals for non-profit and for-profit entities
--------------------------------------------
On Sat, 5/7/16, Nick Cassara <nickc@mtaonline.net> wrote:
Subject: Kolb-List: FYI G rating on Firefly
To: kolb-list@matronics.com
Date: Saturday, May 7, 2016, 5:22 PM
Nick Cassara <nickc@mtaonline.net>
Kolbers,
I have a the New Kolb Aircraft, Co. catalog that says
number.
Fly safe,
Nick Cassara
Palmer, Ak
Forum -
- MATRONICS WEB FORUMS -
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Dralle, List Admin.
Message 3
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| Subject: | Re: Kolb Firestar Progress report |
Rudder flutter on a Kolb is easy to test for: take your feet off the rudder pedals
and wait. If, after a few seconds, the rudder pedals start to pulse back and
forth, and the airplane starts to twitch from side to side, then you can build
a counterbalance.
http://oh2fly.net/oldpoops/pg6.htm
Or else never take your feet off the pedals.
Also - recently there has been a growing trend of not snipping non-pertinent quote
sections. This makes for some ridiculously long entries that do nothing to
edify anybody. It is also contrary to the list guidelines:
"Remember that your post will be included for posterity in an archive
that is growing in size at an extraordinary rate. Try to be concise and
terse in your posts. Avoid overly wordy and lengthy posts and
responses.
- When responding, NEVER quote the *entire* original post in your
response. DO use lines from the original post to help "tune in" the
reader to the topic at hand, but be selective. The impact that
quoting the entire original post has on the size of the archive
can not be overstated!"
--------
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0
Would you consider yourself to be a good person?
https://www.youtube.com/watch?v=VWcDXT6pH7A
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=455973#455973
Message 4
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| Subject: | Re: Kolb Firestar Progress report |
Rudder flutter on a Kolb is easy to test for: take your feet off the rudder
pedals and wait. If, after a few seconds, the rudder pedals start to pulse
back and forth, and the airplane starts to twitch from side to side, then
you can build a counterbalance.
http://oh2fly.net/oldpoops/pg6.htm
Or else never take your feet off the pedals.
Richard Pike
Kolbers:
My MKIII rudder fluttered if I took my feet off the pedals or relaxed slight
foot pressure on them. So did the rudder on my Ultrastar and Firestar.
My fix, rather than add a large device on top of the rudder was the addition
of a second rudder pedal spring on each rudder pedal. Now I can fly with my
feet on the deck without fear of rudder flutter.
A cheap, simple, quick fix.
john h
MKIII
Titus, Alabama
Message 5
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| Subject: | Re: Kolb Firestar Progress report |
Hi John, I forgot that. Yes, the double springs would indeed be quicker, simpler
and lighter. Also, they don't give the birds a place to sit while they poop
on your airplane.
But now I have a ground plane for my antenna. [Wink]
--------
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0
Would you consider yourself to be a good person?
https://www.youtube.com/watch?v=VWcDXT6pH7A
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=455988#455988
Message 6
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| Subject: | Re: FYI G rating on Firefly |
Hmmm... I wouldn't want to assume that's true. Might be, but only Homer
(or a structures engineer) knows for sure. Many non-certificated a/c
are not designed to Part 23 (or its CAA predecessor) standards. And
designing for is not the same as 'having'. :-) And you must factor in
changes that builders may make, either by accident, or to make the
design stronger. ;-)
The prototype of the plane I fly *was* tested to 6Gs, and I try not to
go beyond 4 in mine (so *I* have a 50% margin). In the design that I
fly, going beyond about 6.5-7Gs will often get you permanently bent
metal. Going much beyond 9 (50% margin) can get you broken metal (killed).
My real point is that even if it was tested to 50% beyond rated G load,
the margin is there so you have a margin. If you use it, you don't have
it when you slip up & pull an extra .5.
Charlie
On 5/8/2016 3:11 AM, Bill Berle wrote:
>
> In keeping with a very long and well-understood tradition in aircraft design
and manufacture, there is an additional 50% FOS, or "factor of safety". This means
that the airplane was likely tested to +6G
>
> Bill Berle
> www.ezflaphandle.com - safety & performance upgrade for light aircraft
> www.grantstar.net - winning proposals for non-profit and for-profit entities
>
> --------------------------------------------
> On Sat, 5/7/16, Nick Cassara <nickc@mtaonline.net> wrote:
>
> Subject: Kolb-List: FYI G rating on Firefly
> To: kolb-list@matronics.com
> Date: Saturday, May 7, 2016, 5:22 PM
>
> Nick Cassara <nickc@mtaonline.net>
>
> Kolbers,
>
> I have a the New Kolb Aircraft, Co. catalog that says
> +4 -2g for the Firefly and all the other have the same
> number.
>
> Fly safe,
>
> Nick Cassara
> Palmer, Ak
>
Message 7
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| Subject: | Re: Kolb Firestar Progress report |
Hi John, I forgot that. Yes, the double springs would indeed be quicker,
simpler and lighter. Also, they don't give the birds a place to sit while
they poop on your airplane.
But now I have a ground plane for my antenna. [Wink]
--------
Richard Pike
The birds don't need a rudder counterbalance weight to roost and crap on my
MKIII. There is a lot of other places on and near the airplane they can
take advantage of.
I don't understand "But now I have a ground plane for my antenna. (Wink)"
john h - The clueless.
MKIII
Titus, AL
Message 8
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| Subject: | FYI G rating on Firefly |
Hmmm... I wouldn't want to assume that's true. Might be, but only Homer (or a structures
engineer) knows for sure. Many non-certificated a/c are not designed
to Part 23 (or its CAA predecessor) standards. And designing for is not the
same as 'having'. :-) And you must factor in changes that builders may make,
either by accident, or to make the design stronger. ;-)
Charlie
Kolbers:
I have flown with a G Meter since my Firestar days. Have always had a G Meter
in the MKIII. I like to know what I am doing to the airplane.
Back in my Firestar days I thought the Kolb design was invincible. Therefore,
I did thousands of aerobatics in a heavy Firestar before I finally wore it out.
I can share with you that it is extremely difficult to exceed the G rating
of 4+/2- on a Kolb. The most I was ever able to pull on the Firestar was 5+ and
between 1 and 2 minus. To get 5 G's, I had to work extremely hard. I doubt
the average guy could pull more than 4+ in a Kolb. Don't worry. If you accidentally
do pull 5+, the wings won't come off. Now if you fly like that for
785.0 hours, there's a good chance you will have a catastrophic failure.
I have never performed aerobatics in my MKIII. I have seen 4+ and 2- in some of
the extreme weather I have found myself at times. Normally, really rough air
will see 2+ and 1-.
Your Kolb is not going to break unless you really work hard at doing just that.
john h
mkIII
Titus, Alabama
Message 9
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| Subject: | Re: FYI G rating on Firefly |
Absolutely 100% correct, the reason for a safety margin is to have it and never
use it.
Bill Berle
www.ezflaphandle.com - safety & performance upgrade for light aircraft
www.grantstar.net - winning proposals for non-profit and for-profit entities
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