KR> flying stories ?

[phillipmathe...@bigpond.com]

All the best Mark. Glad to hear you are OK.
I know just how you feel.
Sounds like similar damage as mine had.

They are a mighty aircraft, and easy to repair.

It will be interesting to see your next engine design.

Phil Matheson 

KR> Corvair crank

[laser...@juno.com]

Given that this engine has become such a popular powerplant for experimentals, 
I would have thought someone would be building a forged crank for this motor by 
now since it is the "heart" of any engine.  

Forged cranks ended the crankshaft failures with the VW's so looks like this is 
going to be necessary with the Corvairs if anyone is to trust their engines in 
the future.

Good save there Mark and a great write-up, as usual.  

Mike
KSEE









53 Year Old Mom Looks 33
The Stunning Results of Her Wrinkle Trick Has Botox Doctors Worried
http://thirdpartyoffers.juno.com/TGL3141/4efaaf8df33665dedaast02vuc

KR> Fwd: Cranks and flywheels

[phillipmathe...@bigpond.com]

Also remember a belted gear reduction will take the loads and not the crank, 
the engine can the produce the RPM it was designed to, and produce the HP it 
is said to.

You can also run a larger prop or more pitch or both.

Phil Matheson
KR2

KR> Re: Cranks and Flywheels

[Russell Barmett]

Has anyone ever considered the quality of the line bore in the case and the 
tolorance of the main bearings?  I would think that a very good fit on the main 
bearing journals would help keep the crank from flexing as much. Some people 
may put in a crank and bearings and as long as it turns it is OK maybe leaving 
excessive clearance in the mains.Just thought i would throw that out there 
for what it is worth. 

Russ Barnett
N8227   

KR> See you at Osh

[Dan Heath]

Chris,

I hope you are going to make the KR Gathering this year.

See N64KR at http://KRBuilder.org - Then click on the pics 
See you at the 2012 - KR Gathering in Mt. Vernon, Il – MVN – 40th
Anniversary
There is a time for building and it is almost over.
Daniel R. Heath - Lexington, SC



-Original Message-


hope to see everyone in the KR community at

KR> Fwd: Cranks and flywheels

[Dan Heath]

I would not be so quick to jump to conclusions.  There are many things that
could have played a part in this and no one will know without running a
complete analysis on the damage.  And, then, we may still never know.  The
front bearing is a definite improvement and I would not fly a Corvair engine
without one, at least on a high performance plane.  As for the flywheel,
does the 14# harmonic balancer combined with a prop count for anything
toward a flywheel?  I don't know.

Someone suggested that someone out there should start making cranks.  Well,
someone did.  Brady at Magnificent Machine produced some and I think at
least one is currently in use.  They also eliminated the harmonic balancer.
I was talking to Joe at Revmaster one day about the new engine he was
designing.  He told me that he was getting a crank custom made for his new
engine and that the investment would end up being around a million dollars.
Any takers?

VW cranks used to break until they did the same things that the Corvair
builders are now doing.  I have flown VWs with no extra bearing and with the
so called front bearing like the Force One hub on the Great Plains.  I never
had a crank break.  I wonder how many hours PF Beck has on his Corvair
powered Piet with no front bearing and no broken cranks?

See N64KR at http://KRBuilder.org - Then click on the pics 
See you at the 2012 - KR Gathering in Mt. Vernon, Il – MVN – 40th
Anniversary
There is a time for building and it is almost over.
Daniel R. Heath - Lexington, SC


-Original Message-

Based on the experiences of those who've been there, it seems the big fifth
bearing now being implemented by Corvair builders moderates but doesn't
completely eliminate the effect of the crank bending forces imposed by the
prop

KR> flying stories ?

[Virgil N. Salisbury]

How about a Single rotor Rotary ~100 Hp, Virg


On 12/27/2011 5:19 PM, cgardn628 wrote:
> Mark,
>
> Glad to hear you are okay after the scary #3 crankshaft incident!
>
> Maybe you'll reconsider the Type 4 VW that you were originally going to use
> in your KR2S.
>
> I also had a broken pushrod this year in my 2180 VW due a faulty end cap
> shattering in flight. Flying on 3 cylinders can be interesting as well but
> not as scary as a dead engine.
>
> Best Wishes for the holidays and hope to see everyone in the KR community at
> Oshkosh next year.
>
> Regards
>
> Chris Gardiner
> KR2S C-GKRZ
>

KR> Reading related to Cranks and flywheels

[Tony King]

Running a type 4 VW with a direct drive prop at the 'right' end (from a car
perspective) is considered by many (and proven by some) to be a recipe for
disaster, however that's considered the correct end for a PSRU.  So to
answer the question, the aircraft equivalent of the auto transmission (in
terms of its effect on dampening pulses) probably is the PSRU.

Cheers,

Tony King
Queensland Australia


On 28 December 2011 06:48, Barrett  wrote:

> Good article. The L-98 Corvette engine (and LT-1) when coupled to the
> 6-speed tranny also use a dual mass flywheel, for exactly that same reason.
> When switched to an aluminum flywheel- same results. Another thing too-
> when
> the clutch disc with spring dampeners are changed to one without the
> springs, same thing happens, just takes a bit longer. The Corvettes with
> auto tranny's don't have this problem as the transmission acts as the
> buffer
> (shock & harmonics absorber).
> In our case, I'm sure the problem can be fixed by finding and fixing the
> dynamics of the problem rather than the use of just brute strength (heavier
> crankshaft).
>
> With all else being equal, do planes with constant speed props have the
> same
> problem?
> (grasping at straws here- what would our equivalence be to the auto tranny
> vs. manual gearbox)
> Rubber mounted prop huh??
> Self balancing prop huh??
> More mass in the prop hub??
> 2-blade vs. 3-blade prop??
>
> -Barrett
>
> -Original Message-
> From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net] On Behalf
> Of Glenn Martin
> Sent: Tuesday, December 27, 2011 1:25 PM
> To: KRnet
> Subject: KR> Reading related to Cranks and flywheels
>
> Might be helpful:
>
> http://www.flat6innovations.com/broken-crank
> --
> Glenn Martin,
> KR2 N1333A,
> Biloxi, MS
>
> ___
> Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp
> to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
> please see other KRnet info at http://www.krnet.org/info.html
>
>
> ___
> Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp
> to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
> please see other KRnet info at http://www.krnet.org/info.html
>

KR> Fwd: Cranks and flywheels

[Tony King]

What does the damage (as I understand it) is not the rotational forces but
the bending force the propeller imposes along the axis of the crank.  These
bending loads are practically non existent in an automotive application and
I'm not sure a flywheel of any weight would make much difference.

The problem arises from fact that the centre of lift of each propeller
blade is quite a way off the axis of the crank.  Averaged over time the
'lift' (perhaps more commonly called thrust) generated by each blade is
close enough to the same, but at any instant, the lift generated by each
blade is not the same as the other blades (due the angle of the propeller
to the airstream - which is not always a right angle, imperfections, slight
differences between blades, etc.), resulting in a force that imposes a
bending load on the crank.

Based on the experiences of those who've been there, it seems the big fifth
bearing now being implemented by Corvair builders moderates but doesn't
completely eliminate the effect of the crank bending forces imposed by the
prop.  Having dismissed the flywheel at the start of my email, it's just
occurred to me that a flywheel at the prop end might help reduce the
bending force by way of the gyroscopic effect of the flywheel acting
against the bending force of the prop.

Sadly I don't have the theoretical background to work out whether a
flywheel of tolerable weight and dimensions could make a useful
contribution.  Any takers?

Cheers,

Tony King
Queensland Australia


> On a theoretical note: Isn't the flywheel meant to store the energy
> imparted to the crank between the power pulses? And if that is the case,
> doesn't a lighter flywheel tend to cause the torsion differential
> between the pulses on the crank to increase versus a heavier flywheel
> which will tend to store the energy longer. This is comparable to what a
> filter circuit does in electronics. If I reduce the capacity of a
> filter, then the ripple voltage will increase, especially under heavy
> loads. Perhaps  a heavier flywheel should be considered, especially in
> an engine which is being increased in its power output. I'd be
> interested in hearing the science on this.
>
>

KR> Re:Aluminum Protection

[Seth and Karen Jersild]

Thank you all for your responses.   I'll look at that video and research 
further into alodine for the aluminum.
-Seth

On 12/26/2011 8:45 PM, smwood wrote:
> For aluminum protection: Watch the EAA Hints for Homebuilders video and do
> what Brian Carpenter says.  It works!
> http://www.eaavideo.org/channel.aspx?ch=ch_hints
>
> Anodize is the best (and pricey) aluminum treatment, but next best is
> alodine and doable by anyone right on your work bench at home.
> Zinc chromate is a good primer for a finish coat of a spray paint, but next
> to worthless for aluminum metal protection.  Powder coat is a great looking
> finish and will provide excellent protection as long as the surface does not
> crack or get scratched to the bare metal.  Corrosion can then happily eat
> away under the best looking part and you will not know it until the paint
> can no longer support the load that the metal used to carry.
>
> Sid Wood
> Tri-gear KR-2 N6242
> Mechanicsville, MD, USA
> smw...@md.metrocast.net
>

KR> Fwd: Cranks and flywheels

[Vaughan Thomas]

maybe I should have asked 'gaining some weight and a safety margin isnt such 
a bad idea?' Vaughan Thomas
Hamilton. New Zealand
- Original Message - 
From: "Vaughan Thomas" 
To: "KRnet" 
Sent: Tuesday, December 27, 2011 11:35 PM
Subject: Re: KR> Fwd: Cranks and flywheels


I,m watching the discussion re corvair engine & broken crankshafts with
interest. (I'd like to get a couple of suitable engines having purchased
WW's conversion manual - but the engines dont exist down here in NZ). It
seems Glen martin might be ontoit as to the flywheel thing, can a prop
achieve the power impulse dampening effect like a flywheel, especially on an
engine intended to run a flywheel or torque converter ?  do 3 bladed props
give a better absorption effect?  Has there been significantly more broken
cranks on 2 or 3 blade propped engines?? Perhaps saving some weight but
gaining  a safety margin isnt such a bad idea? What does the guru WW think
about the broken crank scenario? any comments? Vaughan Thomas
Hamilton. New Zealand
- Original Message - 
From: "Glenn Martin" 
To: "KRnet" 
Sent: Tuesday, December 27, 2011 9:24 PM
Subject: KR> Fwd: Cranks and flywheels




 Original Message 
Subject: Cranks and flywheels
List-Post: krnet@list.krnet.org
Date: Tue, 27 Dec 2011 02:16:14 -0600
From: Glenn Martin 
To: KRnet 



On 12/26/2011 9:56 PM, Tony King wrote:
>  One significant factor, regardless of which end it's being driven from,
> is
>  that the torsional loads imposed on the crank in an automotive
> application
>  are vastly smaller than those imposed by a propellor spinning at 3000
> rpm.

On a theoretical note: Isn't the flywheel meant to store the energy
imparted to the crank between the power pulses? And if that is the case,
doesn't a lighter flywheel tend to cause the torsion differential
between the pulses on the crank to increase versus a heavier flywheel
which will tend to store the energy longer. This is comparable to what a
filter circuit does in electronics. If I reduce the capacity of a
filter, then the ripple voltage will increase, especially under heavy
loads. Perhaps  a heavier flywheel should be considered, especially in
an engine which is being increased in its power output. I'd be
interested in hearing the science on this.

-- 
Glenn Martin,
KR2 N1333A,
Biloxi, MS

___
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to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
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Version: 8.5.454 / Virus Database: 271.1.1/4105 - Release Date: 12/26/11 
19:34:00

KR> Reading related to Cranks and flywheels

[Glenn Martin]

Might be helpful:

http://www.flat6innovations.com/broken-crank
-- 
Glenn Martin,
KR2 N1333A,
Biloxi, MS

KR> KR-2 Photo

[smwood]

Here is a photo taken by Bernie Wunder of my KR-2, newly arrived at St. 
Mary's County Airport 2W6, for the FAA airworthiness inspection application. 
The graphics were produced by Wayne's Signs.
http://waynessigns.com/gallery/index.php?page=1=VehicleLettering
Fixing mechanical fuel pump problems and valve cover leaks, but first flight 
is getting close.

Sid Wood
Tri-gear KR-2 N6242
Mechanicsville, MD, USA
smw...@md.metrocast.net

KR> Re:Aluminum Protection

[Paul Gangemi]

Clear thinking, nice landing, ML! Glad you're okay.

Paul
KR2s almost

KR> Fwd: Cranks and flywheels

[Vaughan Thomas]

I,m watching the discussion re corvair engine & broken crankshafts with 
interest. (I'd like to get a couple of suitable engines having purchased 
WW's conversion manual - but the engines dont exist down here in NZ). It 
seems Glen martin might be ontoit as to the flywheel thing, can a prop 
achieve the power impulse dampening effect like a flywheel, especially on an 
engine intended to run a flywheel or torque converter ?  do 3 bladed props 
give a better absorption effect?  Has there been significantly more broken 
cranks on 2 or 3 blade propped engines?? Perhaps saving some weight but 
gaining  a safety margin isnt such a bad idea? What does the guru WW think 
about the broken crank scenario? any comments? Vaughan Thomas
Hamilton. New Zealand
- Original Message - 
From: "Glenn Martin" 
To: "KRnet" 
Sent: Tuesday, December 27, 2011 9:24 PM
Subject: KR> Fwd: Cranks and flywheels




 Original Message 
Subject: Cranks and flywheels
List-Post: krnet@list.krnet.org
Date: Tue, 27 Dec 2011 02:16:14 -0600
From: Glenn Martin 
To: KRnet 



On 12/26/2011 9:56 PM, Tony King wrote:
>  One significant factor, regardless of which end it's being driven from, 
> is
>  that the torsional loads imposed on the crank in an automotive 
> application
>  are vastly smaller than those imposed by a propellor spinning at 3000 
> rpm.

On a theoretical note: Isn't the flywheel meant to store the energy
imparted to the crank between the power pulses? And if that is the case,
doesn't a lighter flywheel tend to cause the torsion differential
between the pulses on the crank to increase versus a heavier flywheel
which will tend to store the energy longer. This is comparable to what a
filter circuit does in electronics. If I reduce the capacity of a
filter, then the ripple voltage will increase, especially under heavy
loads. Perhaps  a heavier flywheel should be considered, especially in
an engine which is being increased in its power output. I'd be
interested in hearing the science on this.

-- 
Glenn Martin,
KR2 N1333A,
Biloxi, MS

___
Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp
to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
please see other KRnet info at http://www.krnet.org/info.html






No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.5.454 / Virus Database: 271.1.1/4103 - Release Date: 12/25/11 
19:34:00

KR> Fwd: Cranks and flywheels

[Glenn Martin]

 Original Message 
Subject:Cranks and flywheels
List-Post: krnet@list.krnet.org
Date:   Tue, 27 Dec 2011 02:16:14 -0600
From:   Glenn Martin 
To: KRnet 



On 12/26/2011 9:56 PM, Tony King wrote:
>  One significant factor, regardless of which end it's being driven from, is
>  that the torsional loads imposed on the crank in an automotive application
>  are vastly smaller than those imposed by a propellor spinning at 3000 rpm.

On a theoretical note: Isn't the flywheel meant to store the energy
imparted to the crank between the power pulses? And if that is the case,
doesn't a lighter flywheel tend to cause the torsion differential
between the pulses on the crank to increase versus a heavier flywheel
which will tend to store the energy longer. This is comparable to what a
filter circuit does in electronics. If I reduce the capacity of a
filter, then the ripple voltage will increase, especially under heavy
loads. Perhaps  a heavier flywheel should be considered, especially in
an engine which is being increased in its power output. I'd be
interested in hearing the science on this.

-- 
Glenn Martin,
KR2 N1333A,
Biloxi, MS

KR> Cranks and flywheels

[Glenn Martin]

On 12/26/2011 9:56 PM, Tony King wrote:
> One significant factor, regardless of which end it's being driven from, is
> that the torsional loads imposed on the crank in an automotive application
> are vastly smaller than those imposed by a propellor spinning at 3000 rpm.
On a theoretical note: Isn't the flywheel meant to store the energy 
imparted to the crank between the power pulses? And if that is the case, 
doesn't a lighter flywheel tend to cause the torsion differential 
between the pulses on the crank to increase versus a heavier flywheel 
which will tend to store the energy longer. This is comparable to what a 
filter circuit does in electronics. If I reduce the capacity of a 
filter, then the ripple voltage will increase, especially under heavy 
loads. Perhaps  a heavier flywheel should be considered, especially in 
an engine which is being increased in its power output. I'd be 
interested in hearing the science on this.

-- 
Glenn Martin,
KR2 N1333A,
Biloxi, MS