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Constant Speed Props, etc.

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fklein(at)orcasonline.com
Guest

Posted: Thu Mar 19, 2009 7:23 pm Post subject: Constant Speed Props, etc.

To those who have yet to make a prop-commitment, these new blades Airmaster is testing look like a vast improvement over the Warp Drive blades.



Fred



Begin forwarded message:

[quote]From: "Airmaster Propellers Sales" <sales(at)airmasterpropellers.com (sales(at)airmasterpropellers.com)>

Date: March 19, 2009 7:54:38 PM PDT

To: "Fred Klein" <fklein(at)orcasonline.com (fklein(at)orcasonline.com)>

Subject: RE: AP332 blades

Reply-To: <sales(at)airmasterpropellers.com (sales(at)airmasterpropellers.com)>

 

Hi Fred



It is true we are testing new propeller types.



For the Europa we are currently in the process of testing a two blade

propeller using Sensenich blades and a three blade propeller using Kiev

(amounst others) Both are at a diameter of 64in.  Each will have advantages

and disadvantages compared to the Warpdrive.



I will make results available once I have a good idea of how these new

propellers will perform.



Regards

Martin



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budyerly(at)msn.com
Guest

Posted: Thu Mar 19, 2009 8:21 pm Post subject: Constant Speed Props, etc.

<?xml:namespace prefix="v" /><?xml:namespace prefix="o" /><![endif]-->  Fred and all,

 Martin will be sending the new blades to me for test also.  I will run  a test of the fixed warp drive, standard Airmaster AP332 with Warp drive blades  and the new Kiev blades.  Probably won't get the two blade for the  Europa test, but I can hope.  We look to have the two blade on a float  plane with longer blades than we use (68").  Look for info to follow, and  postings to my website.  Should be just after Sun n Fun. in early  May...

  

 Bud Yerly

 Custom Flight Creations

 www.customflightcreations.com

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fklein(at)orcasonline.com
Guest

Posted: Thu Mar 19, 2009 10:03 pm Post subject: Constant Speed Props, etc.

On Mar 19, 2009, at 9:11 PM, ALAN YERLY wrote:

 	  Quote: 	
		  Martin will be sending the new blades to me for test also.  I will run a test of the fixed warp drive, standard Airmaster AP332 with Warp drive blades and the new Kiev blades. 	




Bud...Do you know whether or not the new blades are compatible w/ the AP332 hub?

Fred



 [quote][b]

budyerly(at)msn.com
Guest

Posted: Fri Mar 20, 2009 8:39 am Post subject: Constant Speed Props, etc.

<?xml:namespace prefix="v" /><?xml:namespace prefix="o" /><![endif]-->  We haven't firmed that up yet Fred.  

  

 I believe the Sensenich blades are really designed for the new 432 and  much final testing needs to be done.  Other blades are being tested which  appear to be retrofitable (is that a word?).  Frankly I doubt there  will be a significant change over the WD blades, but that is what testing is  for.  As you are aware, wider chord blades require a somewhat  larger base .  I'll keep you guys posted on the testing as I get it as  we don't want to release a product until it is thoroughly tested or make  promises we can't keep.

  

 As you well know I am not a politician.  

  

 Bud

 Custom Flight Creations

 www.customflightcreations.com

 ---

kheindl(at)msn.com
Guest

Posted: Fri Mar 20, 2009 10:58 am Post subject: Constant Speed Props, etc.

  

What is a 432 ?



 



  



  From: budyerly(at)msn.com

To: europa-list(at)matronics.com

Subject: Re: Europa-List: Constant Speed Props C etc.

Date: Fri C 20 Mar 2009 12:32:03 -0400



     We haven't firmed that up yet Fred.  

  

 I believe the Sensenich blades are really designed for the new 432 and much final testing needs to be done.  Other blades are being tested which appear to be retrofitable (is that a word?).  Frankly I doubt there will be a significant change over the WD blades C but that is what testing is for.  As you are aware C wider chord blades require a somewhat larger base .  I'll keep you guys posted on the testing as I get it as we don't want to release a product until it is thoroughly tested or make promises we can't keep.

  

 As you well know I am not a politician.  

  

 Bud

 Custom Flight Creations

 www.customflightcreations.com

 ---

paul.the.aviator(at)gmail
Guest

Posted: Fri Mar 20, 2009 1:07 pm Post subject: Constant Speed Props, etc.

Hi Bud,

  

 I am not an aerodynamicst, not even an amature one but I was wondering why you didn't think the  Kiev blades will be much of an improvement over the Warp Drive blades.  The reason I ask is that I do know that I  get an increase in TAS up to about 10,000' with my AP332 Warpdrive / 914T combination, but after the speed doesnt increase much.  

   

 I hear from the Whirlwind folks that this is not the case for them, higher = faster.

  

 Given that something isn't happening as expected I am concluding that there is some design parameter(s) that are not appropriate for a an aircraft that flies at Europa speeds / altitudes.

  

 Any insight that you could share with me would be appreciated.

  

 Thanks,  Paul

 



 

 On Fri, Mar 20, 2009 at 11:32 AM, ALAN YERLY <budyerly(at)msn.com (budyerly(at)msn.com)> wrote:

 [quote]     Frankly I doubt there will be a significant change over the WD blades, but that is what testing is for.  As you are aware, wider chord blades require a somewhat larger base .  

    As you well know I am not a politician.  

  

 Bud

   



[b]

fklein(at)orcasonline.com
Guest

Posted: Fri Mar 20, 2009 5:18 pm Post subject: Constant Speed Props, etc.

On Mar 20, 2009, at 2:00 PM, Paul McAllister wrote:



 	  Quote: 	
		   I am not an aerodynamicst, not even an amature one but I was  

 wondering why you didn't think the  Kiev blades will be much of an  

 improvement over the Warp Drive blades.


	


Bud,



I too was surprised at your apparent skepticism as to whether those  

Kiev blades may offer improvement over the current WD blades in the  

Airmaster hub.



I had several long emails w/ Martin on the subject...perhaps 2 years  

ago...and my recollection is that he was quite candid about the WD  

blades being less than optimal given the flight envelope and length  

limitations of the blades for the Europa.  My understanding is that  

the WD blade stock is much longer, and when cut down to length  

required, they lose much of their twist...to such an extent I've read  

that the inner portions of the blades create negative thrust under  

certain conditions. I've speculated that the relative lack of twist  

may be a factor in engine cooling...just speculation, I have, of  

course, no direct experience.



Assuming that the "432" references a new hub, I hope it's available  

with other than a Rotax flange.



Fred

budyerly(at)msn.com
Guest

Posted: Fri Mar 20, 2009 9:30 pm Post subject: Constant Speed Props, etc.

<?xml:namespace prefix="v" /><?xml:namespace prefix="o" /><![endif]-->  Paul,

 I am only a junior aerodynamicist.  Propeller blade design is still a  zen art.  Too many theta, beta sigma deltas to patiently wade through and  design a prop.  The math is not beyond me, ( I have a computer program for  doing the gymnastics and iterations, (but my kid the aero engineer has to  get me in to it...go figure).  I can say that most designs take into  account the assumptions of where the max efficiency of their design will  be optimized.  When designing a prop blade, it is hard to get a prop  that does all things well.  We buy a CS prop to accelerate fast, give max  climb and optimum efficiency at the exact torque/power curve for the specified  aircraft at a specified cruise speed and altitude, but propeller blade designers  don't know your plane, engine or the altitudes you intend to use, so they assume  for a specific engine and speed/altitude, and don't tell anyone.  For  you Paul, the next two paragraphs are a bit basic, but somebody  less experienced may glean some knowledge or correct me.  

  

  Example:  For max static thrust and quick acceleration of say a float  plane/airboat, you design the prop so the entire prop blade is pulling very  close to the stall angle based on the rotational speed for takeoff  power/torque and forward speed.  This gets the plane on the step  quickly and off the water.  But, once you pass about 80 Kts the blade  angle of attack falls off due to forward speed, cowl stagnation point  / flow interruption and the reduction of power to max continuous for the  climb.  To design a perfectly optimized fixed pitch propeller, the  following is optimized by trial and error:  For takeoff, the blade bites as  described above.  During the transition to climb, the tip unloads slightly  and the root takes up the difference.  At cruise the tip  unloads further leaving the root to take up the slack.  Balancing this  twist means the propeller designer and aircraft/power plant designer must  cooperate to achieve this goal.  So the fixed pitch designer at WD makes  his blade so that there is extra pitch at the hub decreasing to the tip so as  speed increases the root pulls the load the tip can't, but only to a  point.  Typically 7500-9500 feet and 120 Kts is about max you'll ever get  unless you've got a clean airplane like a Europa and you get 130  Kts...



  

 Take the Airmaster with the Warp Drive (WD) blades.  On a slow  aircraft like a Rans S-7 or a Kitfox.  Let's say their optimum cruise will  be 110 Kts at 7500 feet for that plane.  A fixed 68 inch WD prop can be  twisted to give max static thrust, and high climb, but then the pitch is too low  for optimum cruise, and the plane only makes 105 Kts because the tip is unloaded  and prop efficiency drops.    So we put the WD blades on a CS  prop hub.  Now the static thrust and high climb are there but once at  cruise we adjust the pitch to coarse to allow the prop to bite more and be at  the optimum pitch for 110-115 Kts or a little higher. 

  

 Now let's go to our 914 and 15,000 foot cruise.  The WD blade is a  good strong blade, but the assumed efficient cruise altitude of the blade may  not have been optimized for 15,000 feet and 175 KTAS pulled by an engine  making 70 HP and 70 ft lbs of torque at altitude.  As altitude goes up, we  know the rules about how density affects the TAS.  The blade (wing) of  the prop is now at a higher Reynolds number which results in a lower lift curve  slope.  In the rarified air up there, the dynamic pressure is less so  less lift (or pull) is provided, and the velocity (True) is higher, so the  vector made by the rotational angle of the disk and the Velocity vector  forces the blade to a higher angle of attack to bite (course prop pitch).   The higher altitude decreases the thrust (or lift of the blade) and you find  yourself with the blade generating max lift, and or in fact stalling at some  point and not operating efficiently.  I believe it is a high probability  the torque of the 914 engine is higher than the prop requires for max efficiency  at altitude.  Hence the CS mechanism adjusts the prop to a more coarse  setting to absorb the torque demanded by the throttle, but that puts the  blade at an angle which lowers the overall efficiency of the blade. Therefore  you experience the effect of no appreciable increase in speed the higher you  go.  The WD blade is most probably being over driven by the 914 at  altitude.  I presume you experimented with many manual pitch settings,  manifold pressures and RPM settings looking for max performance.  I am well  behind you as my schedule does not allow a lot of time to climb to altitude and  test, but I am hoping for a break this spring.  My gut feeling will be that  I will need to throttle back to gain efficiency and be satisfied with 40 mpg  instead of 30 and get to my destination a little slower.

  

 From my Airplane Aerodynamics reference by Dommasch, Sherry and Connolly,  "Because of the factors discussed above, we find that the over all shape of a  propeller is determined by the maximum speed at which it must operate  efficiently.  A low-speed planform should be slender with well rounded  tips, whereas a high speed planform should have a large chord, with the maximum  amount of blade area concentrated in the minimum diameter.  Because the  major portion of the thrust is derived from the outer portion of the blades, a  high speed propeller is generally characterized by paddle shaped tips that place  the area where it can best be utilized.

  

 What's the fix?  To translate the above academic explanation, the best  example is to look at WWII prop designs of the VDM propeller used on the ME  109.  Early versions had the thin profile blade we see on our WD narrow  chord blades.  But as engine performance and the demand for  higher altitudes increased, the designers went to a wider prop of more surface  area to absorb the torque, and to create more thrust out of the  blade normally lost due to the effects of higher altitude.  They  were limited by the diameter of the prop due to ground clearance, and production  forced them to stick to three blades so they fattened the blades, increased  the pitch of the root and went to war (see pictures of the Ta 152 for an even  higher altitude and speed prop).  Takeoff performance wasn't that much  better because the larger blade area demanded more torque/power than available  and the pitch was reduced lowering efficiency at takeoff, but mid altitude climb  and acceleration, as well as cruise was improved.  By the way the VDM was a  variable pitch prop, with a visual indicator of prop pitch in the cockpit, not a  constant speed prop.  Talk about pilot work load.  In the US we did  the same for the P-47 by changing the Hamilton Standard prop from  a thin blade to a thicker blade as WD did and made the prop Constant Speed to  reduce pilot work load.   God I love history...

  

 Right now Airmaster is looking at a number of blades that fit our hub and  future hubs.  Problem is, the blade designs are many, and twist  features are not that much different than the WD.  My comment on the Kiev  blade is that it doesn't appear to have much more twist, but it does seem to  have more area.  It is in use on lower altitude/low performance ultralight  and trike aircraft. It is light, but, is its hollow design  tough enough for the 914 at high Q, and for our Europa, all the  Kiev prop blades are longer (67") than we can normally use.  Sensenich  (fixed) and Whirlwind (oil pump driven hydraulic) have wider chord blades  than the WD and may hold an advantage in some areas, but give a thumping  sound as the pressure wave hits the aircraft.  Airmaster does use  their own Europa to test prop blade performance.  In my opinion, if  some blade was significantly better for the three blade AP332, it would be  on there already.   Since we have new meat in the prop market,  there are more choices in the blades, and the Rotax / WD is very popular so  the new blades favor that LSA speed/altitude market now and use a  similar hub attachment and blade design.  I'm afraid there is not  a lot of call for high altitude low power high speed props like we need for  cruise at 15,000 feet.  Also the market has to be satisfied, many  lower performance aircraft enjoy the Airmaster and aren't in need of a major  change, while other markets need a longer two blade prop for static  thrust.  Wider blades restrict feathering or cowl clearance in some  aircraft.  These are the things being evaluated at this time.  It  takes time, money and testing.

  

 Good Night,

  

 Bud

  

  

  

  

  

 [quote]   ---

budyerly(at)msn.com
Guest

Posted: Fri Mar 20, 2009 9:56 pm Post subject: Constant Speed Props, etc.

<?xml:namespace prefix="v" /><?xml:namespace prefix="o" /><![endif]-->  Fred,

 See my other post to Paul.

 I agree about the Warp Drive Blades.  Even in the longer blade lengths  it is not the best blade for altitude.  I find them very good in the 7500  to 9500 foot range for our aircraft using 100 Hp engines.  It is not a  perfect world.  The Kiev blades appear too long also.  Ergo, my  fear is the blade will be less efficient when trimmed for our plane unless those  pesky Russians remake the blades for us as you normally can't whack a hollow  blade prop to length.

  

 Maybe VDM will make a smaller version of the  Me109 blade for our  use.  Anybody know them?

  

 I never thought of myself as skeptical, just cautiously  optimistic...(Sarcastic humor through years of training though.)  Bottom  line testing will tell.  I'm excited about the near future, but  patient.

  

 Bud

 [quote]   ---

rlborger(at)mac.com
Guest

Posted: Sat Mar 21, 2009 4:55 am Post subject: Constant Speed Props, etc.

Bud,



Thanks very much for the excellent and concise description of the problem.  



 Bob Borger

Europa Kit #A221 N914XL, XS Mono, Intercooled 914, Airmaster C/S

http://www.europaowners.org/N914XL

Aircraft Flying!

3705 Lynchburg Dr.

Corinth, TX  76208

Home:  940-497-2123

Cel:  817-992-1117

 



On Mar 21, 2009, at 0:22, ALAN YERLY wrote:

 	  Quote: 	
		  Paul,

I am only a junior aerodynamicist.  Propeller blade design is still a zen art.  Too many theta, beta sigma deltas to patiently wade through and design a prop.  The math is not beyond me, ( I have a computer program for doing the gymnastics and iterations, (but my kid the aero engineer has to get me in to it...go figure).  I can say that most designs take into account the assumptions of where the max efficiency of their design will be optimized.  When designing a prop blade, it is hard to get a prop that does all things well.  We buy a CS prop to accelerate fast, give max climb and optimum efficiency at the exact torque/power curve for the specified aircraft at a specified cruise speed and altitude, but propeller blade designers don't know your plane, engine or the altitudes you intend to use, so they assume for a specific engine and speed/altitude, and don't tell anyone.  For you Paul, the next two paragraphs are a bit basic, but somebody less experienced may glean some knowledge or correct me. 

 

Example:  For max static thrust and quick acceleration of say a float plane/airboat, you design the prop so the entire prop blade is pulling very close to the stall angle based on the rotational speed for takeoff power/torque and forward speed.  This gets the plane on the step quickly and off the water.  But, once you pass about 80 Kts the blade angle of attack falls off due to forward speed, cowl stagnation point / flow interruption and the reduction of power to max continuous for the climb.  To design a perfectly optimized fixed pitch propeller, the following is optimized by trial and error:  For takeoff, the blade bites as described above.  During the transition to climb, the tip unloads slightly and the root takes up the difference.  At cruise the tip unloads further leaving the root to take up the slack.  Balancing this twist means the propeller designer and aircraft/power plant designer must cooperate to achieve this goal.  So the fixed pitch designer at WD makes his blade so that there is extra pitch at the hub decreasing to the tip so as speed increases the root pulls the load the tip can't, but only to a point.  Typically 7500-9500 feet and 120 Kts is about max you'll ever get unless you've got a clean airplane like a Europa and you get 130 Kts...



 

Take the Airmaster with the Warp Drive (WD) blades.  On a slow aircraft like a Rans S-7 or a Kitfox.  Let's say their optimum cruise will be 110 Kts at 7500 feet for that plane.  A fixed 68 inch WD prop can be twisted to give max static thrust, and high climb, but then the pitch is too low for optimum cruise, and the plane only makes 105 Kts because the tip is unloaded and prop efficiency drops.    So we put the WD blades on a CS prop hub.  Now the static thrust and high climb are there but once at cruise we adjust the pitch to coarse to allow the prop to bite more and be at the optimum pitch for 110-115 Kts or a little higher. 

 

Now let's go to our 914 and 15,000 foot cruise.  The WD blade is a good strong blade, but the assumed efficient cruise altitude of the blade may not have been optimized for 15,000 feet and 175 KTAS pulled by an engine making 70 HP and 70 ft lbs of torque at altitude.  As altitude goes up, we know the rules about how density affects the TAS.  The blade (wing) of the prop is now at a higher Reynolds number which results in a lower lift curve slope.  In the rarified air up there, the dynamic pressure is less so less lift (or pull) is provided, and the velocity (True) is higher, so the vector made by the rotational angle of the disk and the Velocity vector forces the blade to a higher angle of attack to bite (course prop pitch).  The higher altitude decreases the thrust (or lift of the blade) and you find yourself with the blade generating max lift, and or in fact stalling at some point and not operating efficiently.  I believe it is a high probability the torque of the 914 engine is higher than the prop requires for max efficiency at altitude.  Hence the CS mechanism adjusts the prop to a more coarse setting to absorb the torque demanded by the throttle, but that puts the blade at an angle which lowers the overall efficiency of the blade. Therefore you experience the effect of no appreciable increase in speed the higher you go.  The WD blade is most probably being over driven by the 914 at altitude.  I presume you experimented with many manual pitch settings, manifold pressures and RPM settings looking for max performance.  I am well behind you as my schedule does not allow a lot of time to climb to altitude and test, but I am hoping for a break this spring.  My gut feeling will be that I will need to throttle back to gain efficiency and be satisfied with 40 mpg instead of 30 and get to my destination a little slower.

 

From my Airplane Aerodynamics reference by Dommasch, Sherry and Connolly, "Because of the factors discussed above, we find that the over all shape of a propeller is determined by the maximum speed at which it must operate efficiently.  A low-speed planform should be slender with well rounded tips, whereas a high speed planform should have a large chord, with the maximum amount of blade area concentrated in the minimum diameter.  Because the major portion of the thrust is derived from the outer portion of the blades, a high speed propeller is generally characterized by paddle shaped tips that place the area where it can best be utilized.

 

What's the fix?  To translate the above academic explanation, the best example is to look at WWII prop designs of the VDM propeller used on the ME 109.  Early versions had the thin profile blade we see on our WD narrow chord blades.  But as engine performance and the demand for higher altitudes increased, the designers went to a wider prop of more surface area to absorb the torque, and to create more thrust out of the blade normally lost due to the effects of higher altitude.  They were limited by the diameter of the prop due to ground clearance, and production forced them to stick to three blades so they fattened the blades, increased the pitch of the root and went to war (see pictures of the Ta 152 for an even higher altitude and speed prop).  Takeoff performance wasn't that much better because the larger blade area demanded more torque/power than available and the pitch was reduced lowering efficiency at takeoff, but mid altitude climb and acceleration, as well as cruise was improved.  By the way the VDM was a variable pitch prop, with a visual indicator of prop pitch in the cockpit, not a constant speed prop.  Talk about pilot work load.  In the US we did the same for the P-47 by changing the Hamilton Standard prop from a thin blade to a thicker blade as WD did and made the prop Constant Speed to reduce pilot work load.   God I love history...

 

Right now Airmaster is looking at a number of blades that fit our hub and future hubs.  Problem is, the blade designs are many, and twist features are not that much different than the WD.  My comment on the Kiev blade is that it doesn't appear to have much more twist, but it does seem to have more area.  It is in use on lower altitude/low performance ultralight and trike aircraft. It is light, but, is its hollow design tough enough for the 914 at high Q, and for our Europa, all the Kiev prop blades are longer (67") than we can normally use.  Sensenich (fixed) and Whirlwind (oil pump driven hydraulic) have wider chord blades than the WD and may hold an advantage in some areas, but give a thumping sound as the pressure wave hits the aircraft.  Airmaster does use their own Europa to test prop blade performance.  In my opinion, if some blade was significantly better for the three blade AP332, it would be on there already.   Since we have new meat in the prop market, there are more choices in the blades, and the Rotax / WD is very popular so the new blades favor that LSA speed/altitude market now and use a similar hub attachment and blade design.  I'm afraid there is not a lot of call for high altitude low power high speed props like we need for cruise at 15,000 feet.  Also the market has to be satisfied, many lower performance aircraft enjoy the Airmaster and aren't in need of a major change, while other markets need a longer two blade prop for static thrust.  Wider blades restrict feathering or cowl clearance in some aircraft.  These are the things being evaluated at this time.  It takes time, money and testing.

 

Good Night,

 

Bud

fklein(at)orcasonline.com
Guest

Posted: Sat Mar 21, 2009 10:22 am Post subject: Constant Speed Props, etc.

For anyone who hasn't OD'ed on this topic, here's a link to what I  

thought was a fascinating article by Paul Lipps and the props he's  

fitted to his O-235 powered Lancair, a ship which shares the Europa's  

niche, i.e., light weight, low powered, high speed cruise, at high(er)  

altitudes.



http://www.eaa.org/experimenter/articles/2009-02_elippse.asp

johnwigney(at)windstream.
Guest

Posted: Sat Mar 21, 2009 5:14 pm Post subject: Constant Speed Props, etc.

Dear Europaphiles,



I have been watching the recent thread on Woodcomp props with much 

interest and I thought that some observations I have mentioned before on 

the Whirl Wind hydraulic constant speed prop may be of interest, see  

http://www.whirlwindaviation.com/series100.php. This prop may not be 

inexpensive but it is good.



I  have flown 600 + hours with mine from new and have found it to be 

completely trouble free and it gives excellent performance. It is also 

one of the lightest props available with a weight of 9.3 lbs. I bought 

it after listening to Kim Prout at Oshkosh many years ago. Paraphrasing, 

he said that it was the most significant single contribution to the 

performance of his Europa. I believe that the Series 100 Whirl Wind prop 

was designed specifically for the Europa and for details of the 

performance of Kim's plane, you can see the CAFE report at 

http://cafefoundation.org/v2/pdf_apr/Europa%20APR.pdf  . As you will 

see, Kim's Europa Classic with the 80 HP 912 is no slouch. On my plane 

for take-off, I set the vernier control to max which gives 5,800 rpm and 

after take-off, one can easily wind back to 5,500 rpm while remaining at 

full throttle. I normally cruise at settings between 5,100 and 5,500 

rpm. If one chooses, the governor will control any speed from about 

3,800 up to 5,800 rpm. Whirl Wind has been producing propellers for 

Unlimited category aerobatic competitors as well as for airshow 

performers for many years so the basic design is very well proven.



To install this prop on a 912/ 912S/914, you must have the gearbox 

modification which allows the governor to supply control pressure oil to 

the hollow prop drive shaft. It is preferable to specify this before you 

take delivery of the engine. The Czech made Jihostroj governor which is 

supplied as part of the package has proved to be completely reliable and 

is very accurate. The governor mounts on the engine auxiliary pad which 

is normally used for a vacuum pump, so one has to rely on non-vacuum 

instruments. I am not familiar with the internals of the Whirlwind hub 

but there is one large central adjustment nut which sets the fine pitch 

stop to give a corresponding max speed of 5,800 rpm at full throttle at 

take off.



I have no business relationship with Whirl Wind. Please contact if you 

have any questions.



Cheers, John



N262WF, mono XS, 912S



Mooresville, North Carolina

704-664-4167

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