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victorbravo(at)sbcglobal.
Guest

Posted: Mon Oct 10, 2016 3:27 pm Post subject: More HKS Engine Interference Questions

Hi again Kolb List, I spent several hours out at the hangar trying to figure out the correct mounting for the HKS engine that will clear the wing parts when folded. I need an answer to another question from those who have been downt his road with the HKS.

What is the acceptable height of the propeller shaft / thrust line on the Firestar, as measured from the Kolb rubber engine mounts, or from the main engine mount support tube on top of the fuselage ?

I was and I am in 100% agreement with the many Kolb List experienced pilots who have said that too high of a thrust line causes problems.The lower the thrust line, the better the airplane flies.

However, even with the aileron torque tubes rotated or moved out of the way during wing folding, the bottom of the HKS exhaust pipe just under the exhaust port is in contact with the inboard "root rib" area of the trailing edge.

Moving the engine FORWARD on the fuselage will solve this problem, but the propeller will hit the bottom of the steel cage just above the tailboom tube.

Raising the engine several inches will also solve this interference problem, but then the thrust line may become high enough to change how the airplane flies.

So the question is... how high can the propeller thrust line be on a Kolb Firestar 2 without causing a change in the aircraft handling?

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, 10/10/16, Richard Pike <thegreybaron(at)charter.net> wrote:

 Subject: Re: syncro of carbs

 To: kolb-list(at)matronics.com

 Date: Monday, October 10, 2016, 9:11 AM

 "Richard Pike" <thegreybaron(at)charter.net>

 racerjerry wrote:

 > I think the confusion is that we are not used to

 looking at a CLOSED SYSTEM.

 > There is no vent to atmosphere and hoses fit tightly

 into bottles.   If vacuum on one bottle is

 greater, fluid will flow into that bottle.  If carbs

 are adjusted equal, fluid flow between bottles will

 stop.  Fluid level does not matter.  Fluid

 transferring between bottles means carbs are not balanced.

 Makes perfect sense. Imbalance of vacuum=movement. Lack of

 movement=balance. Thanks, got it.

 HOWEVER ~ (Much mental activity going on here...  sound

 of gears grinding...) ~ I am thinking that in order to know

 that your carbs were in fact perfectly balanced, you would

 have to balance the carbs, open the system, reconnect the

 system, and run the engine again. 

 Here is why: even in a closed system, the levels of liquid

 would still seek to be even with each other, because if one

 liquid level was higher, it would want to siphon until both

 levels were equal, but it can't. If one bottle was higher,

 it would want to siphon into the lower, but because the

 system is closed, it cannot level itself. However, gravity

 is still placing an inherent imbalance on those liquid

 levels. That gravity imbalance manifests itself as a

 pressure differential, and that is what we are measuring

 when we balance our carbs. 

 In our situation, if the levels stabilize at an unequal

 height during adjustment, I think it is going to preclude

 getting a perfect carb balance because now we have to factor

 in a pressure differential caused by unequal weights of

 liquid in the two bottles. Even in a closed system, that

 pressure differential still has to be a factor somewhere.

 Let's say you start with both bottles level, liquid levels

 the same, hook it up and run the engine. Carbs not balanced,

 siphon occurs and the bottle with the highest vacuum begins

 to fill. You adjust the carbs for balance, and

 siphon/transfer stops. But if one bottle is now 1/3 full and

 the other bottle is 2/3's full, then there is a weight /

 pressure imbalance which my carb vacuum settings have to

 compensate for. One bottle has a much greater weight of

 liquid, which is seeking its own level, but my carb setting

 is preventing that from happening. Which implies to me that

 my carb setting cannot be perfectly balanced if it is

 compensating for a weight imbalance / pressure differential.

 So if I was doing it, at this point I would shut down the

 engine, disconnect the tubing, let the liquid

 siphon/transfer occur until both bottles have level liquid,

 then hook the system up again, run the engine, and if the

 carbs are in fact balanced, no transfer would occur, and the

 liquid levels would stay the same. 

 Then I could quit worrying about it.  [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=461124#461124

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 Dralle, List Admin.

lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Mon Oct 10, 2016 3:49 pm Post subject: More HKS Engine Interference Questions

 	  Quote: 	
		  

 So the question is... how high can the propeller thrust line be on a Kolb Firestar 2 without causing a change in the aircraft handling?

 Bill Berle

  --------



	
Since I am one of the few that have an HKS, I guess that I will have to tell you again that I have mine with 2 inch risers, swing a 66 inch prop giving me about 3/4 of an inch clearance. 

As to your question about how high- I cannot tell you that as I have not gone there as of yet. I can tell you that my wings will fold by turning the ailerons in the extended position when it is folded. I can also tell you that with the engine set the way that it is, when I give it full throttle the plane climbs without my influence on the stick. So apparently I have not raised it too high yet.

I once rode in a Mark three that when full throttle was applied the plane dived without stick up pressure. It scared me!

Larry

_________________
do not archive

stuart(at)harnerfarm.net
Guest

Posted: Mon Oct 10, 2016 4:02 pm Post subject: More HKS Engine Interference Questions

Just a thought.

Move the engine forward to clear the exhaust. Use a spacer to move the prop backward enough to clear the rear spar.

Stuart



--

lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Mon Oct 10, 2016 5:31 pm Post subject: More HKS Engine Interference Questions

Stuart thanks for the reminder.

I forgot a few things. As far as I can tell the engine plate is a standard one from Kolb. I know that it fits a 503 as well as the HKS. The HKS bolts are 3 1/4 inches forward on the plate, and seem to be centered equally. I also got a prop extension from Rick  that I like a lot. It is 2 1/2 inches long.



Larry

_________________
do not archive

victorbravo(at)sbcglobal.
Guest

Posted: Mon Oct 10, 2016 10:12 pm Post subject: More HKS Engine Interference Questions

Thank you Larry and Kolb List'ers for the responses. 



Larry I did remember you told me you had two inch spacers... however I measured my installation, and going from the one inch spacers (what I have now) to two inch spacers (what you have) will still not raise the exhaust pipe UPWARD enough to clear the trailing edge tube of the wing (even with the aileron swung out of the way). 



The problem is only with the wings folded back for storage or  trailering. There's PLENTY of clearance in flying configuration.



Because of the offset between right and left cylinders on an opposed engine, the left wing is a bigger interference problem than the right wing.



The engine might have to go forward, and that means I will have to use a prop extension so the prop doesn't hit the rear of the steel cage. Does anyone know whether I can use a 3 or 4  inch extension on the HKS without putting too much load on the crankshaft or main bearings?



Thank you guys for helping solve this problem. Does any one know whether David Bigelow (HKS powered Firestar 2 in Hawaii) is still flying or participating  in this group?



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, 10/10/16, Larry Cottrell <lcottrell1020(at)gmail.com> wrote:



 Subject: Re: More HKS Engine Interference Questions

 To: "kolb-list(at)matronics.com" <kolb-list(at)matronics.com>

 Date: Monday, October 10, 2016, 4:48 PM

 

 

 

 

 So the question is... how high can the propeller thrust line

 be on a Kolb Firestar 2 without causing a change in the

 aircraft handling?

 

 Bill Berle

   --------

 

 Since I am one of the few that have an

 HKS, I guess that I will have to tell you again that I have

 mine with 2 inch risers, swing a 66 inch prop giving me

 about 3/4 of an inch clearance. 

 As to your question about how high- I cannot tell

 you that as I have not gone there as of yet. I can tell you

 that my wings will fold by turning the ailerons in the

 extended position when it is folded. I can also tell you

 that with the engine set the way that it is, when I give it

 full throttle the plane climbs without my influence on the

 stick. So apparently I have not raised it too high

 yet.

 I once rode in a Mark three that when full

 throttle was applied the plane dived without stick up

 pressure. It scared me!Larry

victorbravo(at)sbcglobal.
Guest

Posted: Mon Oct 10, 2016 10:28 pm Post subject: More HKS Engine Interference Questions

I may have found the problem why Larry's installation is different than mine !



The hotos he was kind enough tos end show exhaust pipes that are NOT separated just past the exhaust port. Mine have a break, with a "Swivel joint" and springs, just 2 inches outside of the exhaust port. These undoubtedly take up more room, and make the exhaust pipe hang down a couple of inches lower under the engine, than Larry's "solid, no swivel/spring joint" system.



So in order to have the thrust line in the best possible position (so I can get the great Kolb handling that I've been hearing about), I may wind up having to make up a new exhaust system that takes up less space, or routes the exhaust pipes a different direction, etc..



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, 10/10/16, Larry Cottrell <lcottrell1020(at)gmail.com> wrote:



 Subject: Re: More HKS Engine Interference Questions

 To: "kolb-list(at)matronics.com" <kolb-list(at)matronics.com>

 Date: Monday, October 10, 2016, 4:48 PM

 

 

 

 

 So the question is... how high can the propeller thrust line

 be on a Kolb Firestar 2 without causing a change in the

 aircraft handling?

 

 Bill Berle

   --------

 

 Since I am one of the few that have an

 HKS, I guess that I will have to tell you again that I have

 mine with 2 inch risers, swing a 66 inch prop giving me

 about 3/4 of an inch clearance. 

 As to your question about how high- I cannot tell

 you that as I have not gone there as of yet. I can tell you

 that my wings will fold by turning the ailerons in the

 extended position when it is folded. I can also tell you

 that with the engine set the way that it is, when I give it

 full throttle the plane climbs without my influence on the

 stick. So apparently I have not raised it too high

 yet.

 I once rode in a Mark three that when full

 throttle was applied the plane dived without stick up

 pressure. It scared me!Larry

lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Tue Oct 11, 2016 5:28 am Post subject: More HKS Engine Interference Questions

Have you checked with Jerry (at)Green Sky? He may be able to supply the pipes that I have. That would have been my only option with my remote location. I am sure there are a few more muffler shops where you are.Larry

On Tue, Oct 11, 2016 at 12:22 AM, 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)>

 

 I may have found the problem why Larry's installation is different than mine !

 

 The hotos he was kind enough tos end show exhaust pipes that are NOT separated just past the exhaust port. Mine have a break, with a "Swivel joint" and springs, just 2 inches outside of the exhaust port. These undoubtedly take up more room, and make the exhaust pipe hang down a couple of inches lower under the engine, than Larry's "solid, no swivel/spring joint" system.

 

 So in order to have the thrust line in the best possible position (so I can get the great Kolb handling that I've been hearing about), I may wind up having to make up a new exhaust system that takes up less space, or routes the exhaust pipes a different direction, etc..

 

 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, 10/10/16, Larry Cottrell <lcottrell1020(at)gmail.com (lcottrell1020(at)gmail.com)> wrote:

 

  Subject: Re: More HKS Engine Interference Questions

  To: "kolb-list(at)matronics.com (kolb-list(at)matronics.com)" <kolb-list(at)matronics.com (kolb-list(at)matronics.com)>

  Date: Monday, October 10, 2016, 4:48 PM

 

 

 

 

  So the question is... how high can the propeller thrust line

  be on a Kolb Firestar 2 without causing a change in the

  aircraft handling?

 

  Bill Berle

    --------

 

  Since I am one of the few that have an

  HKS, I guess that I will have to tell you again that I have

  mine with 2 inch risers, swing a 66 inch prop giving me

  about 3/4 of an inch clearance. 

  As to your question about how high- I cannot tell

  you that as I have not gone there as of yet. I can tell you

  that my wings will fold by turning the ailerons in the

  extended position when it is folded. I can also tell you

  that with the engine set the way that it is, when I give it

  full throttle the plane climbs without my influence on the

  stick. So apparently I have not raised it too high

  yet.

  I once rode in a Mark three that when full

  throttle was applied the plane dived without stick up

  pressure. It scared me!Larry 

 

 

 

 ====================================

 -List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?Kolb-List

 ====================================

  FORUMS -

 eferrer" target="_blank">http://forums.matronics.com

 ====================================

 WIKI -

 errer" target="_blank">http://wiki.matronics.com

 ====================================

 b Site -

           -Matt Dralle, List Admin.

 rel="noreferrer" target="_blank">http://www.matronics.com/contribution

 ====================================

 

 

 

 	




-- 

The older I get, the less tolerant I am of those who are intolerant of others.





If you forward this email, or any part of it, please remove my email address before sending.

_________________
do not archive

victorbravo(at)sbcglobal.
Guest

Posted: Tue Oct 11, 2016 9:09 am Post subject: More HKS Engine Interference Questions

Yes we have plenty of welding and muffler shops here, I'm sure I can get anything I need made. I have an FAA/Boeing/Lockheed approved weld shop that does my certified airplane parts. Larry if you are stuck and you need something made to a drawing, I can definitely put you in the right hands.



To be honest, this whole interference thing has been making me crazy (crazier), since I have photos of at least two good HKS installations on this same FS2 airframe without creating this problem. I just couldn't imagine everyone else having to scratch their head over this for months like I did.



So now... since I will have to modify or change the exhaust system (because the one I got with the engine will not work as-is).... the question becomes: Where is the very best possible place to route the exhaust and mount the muffler on the Firestar/HKS combination?



I have read Larry's postings and e-mails (thank you!) with an explanation of how he feels the muffler prevented enough airflow from getting to the cylinders when it is mounted in front of the engine. Larry also mentioned that it created a lot of drag, which he had to fix using an airflow baffle plate behind it.



So perhaps the top of the wing in front of the engine is not a good place for the muffler on this aircraft?



Has anyone mounted the muffler underneath the bottom of the fuselage, at the intersection of the steel cage and fuselage tube ? This would put the muffler a lot further away from blocking airflow to the cylinders (and keep the noise further away from the pilot's head), at the cost of another four feet of tubing weight. 



I have planned on using an aluminum muffler to reduce weight, because all of you on the Kolb list have convinced me that reducing weight is a primary consideration. The stock HKS cylindrical steel muffler weighs at least 12 pounds by my estimate, and an equivalent aluminum one might be half that. That's a big chunk of weight that can be removed, even if the muffler will not last as long as steel would.



What do you guys think is the best possible location for the exhaust and muffler, if you had the chance to start with a clean sheet of paper?



Bill Berle

www.ezflaphandle.com  - safety & performance upgrade for light aircraft

www.grantstar.net           - winning proposals for non-profit and for-profit entities



--------------------------------------------

On Tue, 10/11/16, Larry Cottrell <lcottrell1020(at)gmail.com> wrote:



 Subject: Re: More HKS Engine Interference Questions

 To: "kolb-list(at)matronics.com" <kolb-list(at)matronics.com>

 Date: Tuesday, October 11, 2016, 6:28 AM

 

 Have you checked with

 Jerry (at)Green Sky? He may be able to supply the pipes that I

 have. That would have been my only option with my remote

 location. I am sure there are a few more muffler shops where

 you are.Larry

 On Tue, Oct 11, 2016

 at 12:22 AM, Bill Berle <victorbravo(at)sbcglobal.net>

 wrote:

 

 Bill Berle <victorbravo(at)sbcglobal.net>

 

 

 

 I may have found the problem why Larry's installation is

 different than mine !

 

 

 

 The hotos he was kind enough tos end show exhaust pipes that

 are NOT separated just past the exhaust port. Mine have a

 break, with a "Swivel joint" and springs, just 2

 inches outside of the exhaust port. These undoubtedly take

 up more room, and make the exhaust pipe hang down a couple

 of inches lower under the engine, than Larry's

 "solid, no swivel/spring joint" system.

 

 

 

 So in order to have the thrust line in the best possible

 position (so I can get the great Kolb handling that I've

 been hearing about), I may wind up having to make up a new

 exhaust system that takes up less space, or routes the

 exhaust pipes a different direction, etc..

 

 

 

 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, 10/10/16, Larry Cottrell <lcottrell1020(at)gmail.com>

 wrote:

 

 

 

  Subject: Re: More HKS Engine Interference

 Questions

 

  To: "kolb-list(at)matronics.com"

 <kolb-list(at)matronics.com>

 

  Date: Monday, October 10, 2016, 4:48 PM

 

 

 

 

 

 

 

 

 

  So the question is... how high can the propeller thrust

 line

 

  be on a Kolb Firestar 2 without causing a change in the

 

  aircraft handling?

 

 

 

  Bill Berle

 

    --------

 

 

 

  Since I am one of the few that have an

 

  HKS, I guess that I will have to tell you again that I

 have

 

  mine with 2 inch risers, swing a 66 inch prop giving me

 

  about 3/4 of an inch clearance. 

 

  As to your question about how high- I cannot tell

 

  you that as I have not gone there as of yet. I can tell

 you

 

  that my wings will fold by turning the ailerons in the

 

  extended position when it is folded. I can also tell you

 

  that with the engine set the way that it is, when I give

 it

 

  full throttle the plane climbs without my influence on

 the

 

  stick. So apparently I have not raised it too high

 

  yet.

 

  I once rode in a Mark three that when full

 

  throttle was applied the plane dived without stick up

 

  pressure. It scared me!Larry 

 

 

 

 

 

 

 

 ==== ============================== ==

 

 -List" rel="noreferrer"

 target="_blank">http://www.matronics.com/

 Navigator?Kolb-List

 

 ==== ============================== ==

 

  FORUMS -

 

 eferrer"

 target="_blank">http://forums.matronics.com

 

 ==== ============================== ==

 

 WIKI -

 

 errer"

 target="_blank">http://wiki.matronics.com

 

 ==== ============================== ==

 

 b Site -

 

           -Matt Dralle, List Admin.

 

 rel="noreferrer"

 target="_blank">http://www.matronics.com/

 contribution

 

 ==== ============================== ==

 

 

 

 

 

 

 

 

 

 

 -- 

 The

 older I get, the less tolerant I am of those who are

 intolerant of others.

 If you forward this email, or any part of

 it, please remove my email address before sending.

neilsenrm(at)gmail.com
Guest

Posted: Tue Oct 11, 2016 10:59 am Post subject: More HKS Engine Interference Questions

Bill/All

When I was building my VW powered MKIIIC I put a motor cycle glass pack muffler on my engine. I started with a dune buggy 4 in to one system that I reworked a bunch to get it to fit. I couldn't see putting the big heavy steel muffler on my airplane so I put a glass pack motorcycle muffler on it. Later on I discovered that the glass had blow out of the muffler but the engine wasn't any louder. So my next step was to eliminate the muffler completely. The engine produced more power, the plane is lighter and was again no louder. 

The noise from my VW comes from the prop and engine vibrations coming through the rubber engine mount, but that's another story. With a pusher engine can you hear the exhaust over the prop noise? I can't hear mine in the cockpit and my fly over noise at 60% cruise power is quieter than the average Cessna. So do you even need or want a muffler???

Have you 912 guys ever flown without a muffler? The 2 stroke engines a different animal and are tuned for the back pressure. Maybe the higher RPM engines need a bit of silencing?

Rick Neilsen

Redrive VW Powered MKIIIC

On Tue, Oct 11, 2016 at 1:09 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)>

 

 Yes we have plenty of welding and muffler shops here, I'm sure I can get anything I need made. I have an FAA/Boeing/Lockheed approved weld shop that does my certified airplane parts. Larry if you are stuck and you need something made to a drawing, I can definitely put you in the right hands.

 

 To be honest, this whole interference thing has been making me crazy (crazier), since I have photos of at least two good HKS installations on this same FS2 airframe without creating this problem. I just couldn't imagine everyone else having to scratch their head over this for months like I did.

 

 So now... since I will have to modify or change the exhaust system (because the one I got with the engine will not work as-is).... the question becomes: Where is the very best possible place to route the exhaust and mount the muffler on the Firestar/HKS combination?

 

 I have read Larry's postings and e-mails (thank you!) with an explanation of how he feels the muffler prevented enough airflow from getting to the cylinders when it is mounted in front of the engine. Larry also mentioned that it created a lot of drag, which he had to fix using an airflow baffle plate behind it.

 

 So perhaps the top of the wing in front of the engine is not a good place for the muffler on this aircraft?

 

 Has anyone mounted the muffler underneath the bottom of the fuselage, at the intersection of the steel cage and fuselage tube ? This would put the muffler a lot further away from blocking airflow to the cylinders (and keep the noise further away from the pilot's head), at the cost of another four feet of tubing weight.

 

 I have planned on using an aluminum muffler to reduce weight, because all of you on the Kolb list have convinced me that reducing weight is a primary consideration. The stock HKS cylindrical steel muffler weighs at least 12 pounds by my estimate, and an equivalent aluminum one might be half that. That's a big chunk of weight that can be removed, even if the muffler will not last as long as steel would.

 

 What do you guys think is the best possible location for the exhaust and muffler, if you had the chance to start with a clean sheet of paper?

 

 Bill Berle

 www.ezflaphandle.com  - safety & performance upgrade for light aircraft

 www.grantstar.net           - winning proposals for non-profit and for-profit entities

 

 --------------------------------------------

 On Tue, 10/11/16, Larry Cottrell <lcottrell1020(at)gmail.com (lcottrell1020(at)gmail.com)> wrote:

 

  Subject: Re: More HKS Engine Interference Questions

  To: "kolb-list(at)matronics.com (kolb-list(at)matronics.com)" <kolb-list(at)matronics.com (kolb-list(at)matronics.com)>

  Date: Tuesday, October 11, 2016, 6:28 AM

 

  Have you checked with

  Jerry (at)Green Sky? He may be able to supply the pipes that I

  have. That would have been my only option with my remote

  location. I am sure there are a few more muffler shops where

  you are.Larry

  On Tue, Oct 11, 2016

  at 12:22 AM, Bill Berle <victorbravo(at)sbcglobal.net (victorbravo(at)sbcglobal.net)>

  wrote:

  --> Kolb-List message posted by:

  Bill Berle <victorbravo(at)sbcglobal.net (victorbravo(at)sbcglobal.net)>

 

 

 

  I may have found the problem why Larry's installation is

  different than mine !

 

 

 

  The hotos he was kind enough tos end show exhaust pipes that

  are NOT separated just past the exhaust port. Mine have a

  break, with a "Swivel joint" and springs, just 2

  inches outside of the exhaust port. These undoubtedly take

  up more room, and make the exhaust pipe hang down a couple

  of inches lower under the engine, than Larry's

  "solid, no swivel/spring joint" system.

 

 

 

  So in order to have the thrust line in the best possible

  position (so I can get the great Kolb handling that I've

  been hearing about), I may wind up having to make up a new

  exhaust system that takes up less space, or routes the

  exhaust pipes a different direction, etc..

 

 

 

  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, 10/10/16, Larry Cottrell <lcottrell1020(at)gmail.com (lcottrell1020(at)gmail.com)>

  wrote:

 

 

 

   Subject: Re: More HKS Engine Interference

  Questions

 

   To: "kolb-list(at)matronics.com (kolb-list(at)matronics.com)"

  <kolb-list(at)matronics.com (kolb-list(at)matronics.com)>

 

   Date: Monday, October 10, 2016, 4:48 PM

 

 

 

 

 

 

 

 

 

   So the question is... how high can the propeller thrust

  line

 

   be on a Kolb Firestar 2 without causing a change in the

 

   aircraft handling?

 

 

 

   Bill Berle

 

     --------

 

 

 

   Since I am one of the few that have an

 

   HKS, I guess that I will have to tell you again that I

  have

 

   mine with 2 inch risers, swing a 66 inch prop giving me

 

   about 3/4 of an inch clearance. 

 

   As to your question about how high- I cannot tell

 

   you that as I have not gone there as of yet. I can tell

  you

 

   that my wings will fold by turning the ailerons in the

 

   extended position when it is folded. I can also tell you

 

   that with the engine set the way that it is, when I give

  it

 

   full throttle the plane climbs without my influence on

  the

 

   stick. So apparently I have not raised it too high

 

   yet.

 

   I once rode in a Mark three that when full

 

   throttle was applied the plane dived without stick up

 

   pressure. It scared me!Larry 

 

 

 

 

 

 

 

  ==== ============================== ==

 

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lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Tue Oct 11, 2016 3:39 pm Post subject: More HKS Engine Interference Questions

Sorry today was town day, and that takes all day.



The placement of the muffler causes more problems than it solves. It screws up the wind needed to cool the engine, and slows the plane. I do not know if this engine needs a muffler? ( back pressure etc) If it didn't I would be thinking about collecting the two pipes in the middle between the cage and the prop having it come out below the boom tube. I would still put the oil cooler on the back of the cage however.

You still may need to cover and funnel the wind over the cylinder heads, if so let me know because I have drawings of the cover needed for that.

Larry

_________________
do not archive

Richard Pike

Joined: 09 Jan 2006
Posts: 1671
Location: Blountville, Tennessee

Posted: Tue Oct 11, 2016 4:02 pm Post subject: Re: More HKS Engine Interference Questions

 	  lcottrell wrote: 	
		  Sorry today was town day, and that takes all day.



The placement of the muffler causes more problems than it solves. It screws up the wind needed to cool the engine, and slows the plane. I do not know if this engine needs a muffler? ( back pressure etc) If it didn't I would be thinking about collecting the two pipes in the middle between the cage and the prop having it come out below the boom tube. I would still put the oil cooler on the back of the cage however.

You still may need to cover and funnel the wind over the cylinder heads, if so let me know because I have drawings of the cover needed for that.

Larry 	




This particular thread has me really interested, even though I don't own an HKS. Larry; can you post a picture or two of your HKS on the airplane? Would like to see it.

_________________
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0

Forgiving is tough, being forgiven is wonderful, and God's grace really is amazing.

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Thu Oct 13, 2016 7:38 pm Post subject: More HKS Engine Interference Questions

Brother Jim and I mounted the first 912 on a MKIII.  There were no aftermarket exhaust systems available in 1993.  Jim welded up four 18" exhaust stacks.  180 degrees out the exhaust port and a 90 degree bend to make them exhaust out the left and right side.  Sounded great on the ground, but at 5000 RPM on the flight from Titus, AL, to Lakeland, FL, the top of my head was ready to come off.  Don't know if any of you all were at S&F 1994.  The 912 sounded like a Formula One screaming down the straightway at WOT.  Did sound good, but was God awful loud.  Homer Kolb loved it, but the UL police at Paradise City didn't.  They complained to me, but Homer said don't worry about it.

 

Was nice to get an aftermarket exhaust that was somewhat more quieter.

 

john h

MKIII

Beatty, Nevada

 

From: owner-kolb-list-server(at)matronics.com [mailto:owner-kolb-list-server(at)matronics.com] On Behalf Of Rick Neilsen

Sent: Tuesday, October 11, 2016 12:58 PM

To: kolb-list(at)matronics.com

Subject: Re: More HKS Engine Interference Questions



 

Bill/All



 



When I was building my VW powered MKIIIC I put a motor cycle glass pack muffler on my engine. I started with a dune buggy 4 in to one system that I reworked a bunch to get it to fit. I couldn't see putting the big heavy steel muffler on my airplane so I put a glass pack motorcycle muffler on it. Later on I discovered that the glass had blow out of the muffler but the engine wasn't any louder. So my next step was to eliminate the muffler completely. The engine produced more power, the plane is lighter and was again no louder. 



 



The noise from my VW comes from the prop and engine vibrations coming through the rubber engine mount, but that's another story. With a pusher engine can you hear the exhaust over the prop noise? I can't hear mine in the cockpit and my fly over noise at 60% cruise power is quieter than the average Cessna. So do you even need or want a muffler???



 



Have you 912 guys ever flown without a muffler? The 2 stroke engines a different animal and are tuned for the back pressure. Maybe the higher RPM engines need a bit of silencing?



 



Rick Neilsen



Redrive VW Powered MKIIIC

 

On Tue, Oct 11, 2016 at 1:09 PM, Bill Berle <victorbravo(at)sbcglobal.net (victorbravo(at)sbcglobal.net)> wrote:

--> Kolb-List message posted by: Bill Berle <victorbravo(at)sbcglobal.net (victorbravo(at)sbcglobal.net)>



Yes we have plenty of welding and muffler shops here, I'm sure I can get anything I need made. I have an FAA/Boeing/Lockheed approved weld shop that does my certified airplane parts. Larry if you are stuck and you need something made to a drawing, I can definitely put you in the right hands.



To be honest, this whole interference thing has been making me crazy (crazier), since I have photos of at least two good HKS installations on this same FS2 airframe without creating this problem. I just couldn't imagine everyone else having to scratch their head over this for months like I did.



So now... since I will have to modify or change the exhaust system (because the one I got with the engine will not work as-is).... the question becomes: Where is the very best possible place to route the exhaust and mount the muffler on the Firestar/HKS combination?



I have read Larry's postings and e-mails (thank you!) with an explanation of how he feels the muffler prevented enough airflow from getting to the cylinders when it is mounted in front of the engine. Larry also mentioned that it created a lot of drag, which he had to fix using an airflow baffle plate behind it.



So perhaps the top of the wing in front of the engine is not a good place for the muffler on this aircraft?



Has anyone mounted the muffler underneath the bottom of the fuselage, at the intersection of the steel cage and fuselage tube ? This would put the muffler a lot further away from blocking airflow to the cylinders (and keep the noise further away from the pilot's head), at the cost of another four feet of tubing weight.



I have planned on using an aluminum muffler to reduce weight, because all of you on the Kolb list have convinced me that reducing weight is a primary consideration. The stock HKS cylindrical steel muffler weighs at least 12 pounds by my estimate, and an equivalent aluminum one might be half that. That's a big chunk of weight that can be removed, even if the muffler will not last as long as steel would.



What do you guys think is the best possible location for the exhaust and muffler, if you had the chance to start with a clean sheet of paper?



Bill Berle

www.ezflaphandle.com  - safety & performance upgrade for light aircraft

www.grantstar.net           - winning proposals for non-profit and for-profit entities



--------------------------------------------

On Tue, 10/11/16, Larry Cottrell <lcottrell1020(at)gmail.com (lcottrell1020(at)gmail.com)> wrote:



 Subject: Re: More HKS Engine Interference Questions

 To: "kolb-list(at)matronics.com (kolb-list(at)matronics.com)" <kolb-list(at)matronics.com (kolb-list(at)matronics.com)>

 Date: Tuesday, October 11, 2016, 6:28 AM



 Have you checked with

 Jerry (at)Green Sky? He may be able to supply the pipes that I

 have. That would have been my only option with my remote

 location. I am sure there are a few more muffler shops where

 you are.Larry

 On Tue, Oct 11, 2016

 at 12:22 AM, Bill Berle <victorbravo(at)sbcglobal.net (victorbravo(at)sbcglobal.net)>

 wrote:

 --> Kolb-List message posted by:

 Bill Berle <victorbravo(at)sbcglobal.net (victorbravo(at)sbcglobal.net)>



 I may have found the problem why Larry's installation is

 different than mine !



 The hotos he was kind enough tos end show exhaust pipes that

 are NOT separated just past the exhaust port. Mine have a

 break, with a "Swivel joint" and springs, just 2

 inches outside of the exhaust port. These undoubtedly take

 up more room, and make the exhaust pipe hang down a couple

 of inches lower under the engine, than Larry's

 "solid, no swivel/spring joint" system.



 So in order to have the thrust line in the best possible

 position (so I can get the great Kolb handling that I've

 been hearing about), I may wind up having to make up a new

 exhaust system that takes up less space, or routes the

 exhaust pipes a different direction, etc..



 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, 10/10/16, Larry Cottrell <lcottrell1020(at)gmail.com (lcottrell1020(at)gmail.com)>

 wrote:



  Subject: Re: More HKS Engine Interference

 Questions



  To: "kolb-list(at)matronics.com (kolb-list(at)matronics.com)"

 <kolb-list(at)matronics.com (kolb-list(at)matronics.com)>



  Date: Monday, October 10, 2016, 4:48 PM



  So the question is... how high can the propeller thrust

 line



  be on a Kolb Firestar 2 without causing a change in the



  aircraft handling?



  Bill Berle



    --------



  Since I am one of the few that have an



  HKS, I guess that I will have to tell you again that I

 have



  mine with 2 inch risers, swing a 66 inch prop giving me



  about 3/4 of an inch clearance. 



  As to your question about how high- I cannot tell



  you that as I have not gone there as of yet. I can tell

 you



  that my wings will fold by turning the ailerons in the



  extended position when it is folded. I can also tell you



  that with the engine set the way that it is, when I give

 it



  full throttle the plane climbs without my influence on

 the



  stick. So apparently I have not raised it too high



  yet.



  I once rode in a Mark three that when full



  throttle was applied the plane dived without stick up



  pressure. It scared me!Larry 



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MKIII/912ULS
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Titus, Alabama

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