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Propeller Sizing

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Monoman

Joined: 01 Nov 2020
Posts: 22

Posted: Tue Dec 28, 2021 2:22 am Post subject: Propeller Sizing

Hello Group

Firstly apologies if this is a repeat as I was not clear if the original had sent.

I am currently changing the engine on my classic mono (const no 33) from a Rotax 80HP to a 100HP unit.

The original engine was fitted with an Airmaster 3 blade VP fitted with Warp Drive blades (T12981) giving a swept Dia of 62". I am very keen to retain the Airmaster hub and have been advised by Airmaster that this set up should work for the 100HP engine.

However I have also been advised that these blades will not be suitable and should change to Warp Drive blades giving a swept Dia of 64".

My question is are any of you classic mono flyers out there using a 64" prop on an Airmaster VP hub and has it worked well?



Thanks

Mike

G-DURO

Dave Disney

Joined: 16 Aug 2010
Posts: 54
Location: Weston-Super-Mare

Posted: Tue Dec 28, 2021 3:32 am Post subject: Re: Propeller Sizing

Hi Mike,



Your choice of propellers is governed by the LAA. They have a document 'LAA Propeller Type List - PTL/1 listing approved props for the Europa/engine combinations, getting approval will be easier if you stick to something from the list.



http://www.lightaircraftassociation.co.uk/engineering/NewMods/Aircraft_Type_Files/247%20-%20EUROPA.pdf



Cheers

Dave

G-RJWX

Monoman

Joined: 01 Nov 2020
Posts: 22

Posted: Tue Dec 28, 2021 4:20 am Post subject: Propeller Sizing

Thanks for the reply Dave, I am aware of this list but it is not exhaustive

as I understand that there are more options that have been individually

approved.

I am also in contact with the LAA who thought that a request like this might

be useful.

I am hoping that someone has indeed fitted either a Warp Drive or other

blade type of 64" on an Airmaster hub to their classic mono.

Cheers

Mike



--

budyerly@msn.com

Joined: 05 Oct 2019
Posts: 288
Location: Florida USA

Posted: Tue Dec 28, 2021 8:42 am Post subject: Re: Propeller Sizing

Mike,

My website has how to select a prop for your Rotax.



The 62 inch Warp Drive Taper blade is fine for most 80HP Rotax powerplants.

The Rotax 912ULS 100HP has significantly more torque and the 62 inch tapered blade is not very efficient.  My US folks were very disapointed with trying to use this short tapered blade on the 912ULS in both the Airmaster and the fixed pitch versions.



The blade angle will be quite high and takeoff will be shortened, climb will be less and the cruise will be about 5 knots slower.  The 80HP Rotax won't spin a wide chord 64 inch without lugging the engine down.  There is just not enough torque.  The tip at takeoff is not able to bite for good performance.



The LAA recommendations is for the Warp Drive Standard (wide chord) blade of 64 inch for the Europa (which limits the length for the airframe to 64 inches) and was the standard Airmaster for a number of years.  The 100HP Rotax has the higher torque and can spin the wider and longer props with authority.



Also available for the cost of a blade change is the Sensenich high speed blades.  Whirlwind has a blade but due to Covid lockdowns in California lead time is many months.  Sensenich and Warp Drive are made in free States so production and labor issues are not a major problem for delivery at this time.  Airmaster will build you up a set of blades and ferrules ready to mount.  It will cost you but it is worth it. 



Contact: Dirk Oyen

Oyen CTR (Europe Sales and Service)

Hemelrijk 61

Heusen-Zolder

Limburg 3550

Belgium



E: dirk.oyen1(at)telenet.be

M: +32 477 25 80 28



Website: www.propellor.com your European Airmaster Dealer.  He has the experience you will need to draw on in the UK (See the Airmaster Contacts section for resellers.) 



I have been happy with all the US manufactured blades in the Airmaster Hub. 

 And NO, you personally can't change the blades yourself.



Best Regards,

Bud Yerly

US Airmaster Dealer

budyerly@msn.com

Joined: 05 Oct 2019
Posts: 288
Location: Florida USA

Posted: Tue Dec 28, 2021 8:43 am Post subject: Re: Propeller Sizing

Mike,

My website has how to select a prop for your Rotax.



The 62 inch Warp Drive Taper blade is fine for most 80HP Rotax powerplants.

The Rotax 912ULS 100HP has significantly more torque and the 62 inch tapered blade is not very efficient.  My US folks were very disapointed with trying to use this short tapered blade on the 912ULS in both the Airmaster and the fixed pitch versions.



The blade angle will be quite high and takeoff will be shortened, climb will be less and the cruise will be about 5 knots slower.  The 80HP Rotax won't spin a wide chord 64 inch without lugging the engine down.  There is just not enough torque.  The tip at takeoff is not able to bite for good performance.



The LAA recommendations is for the Warp Drive Standard (wide chord) blade of 64 inch for the Europa (which limits the length for the airframe to 64 inches) and was the standard Airmaster for a number of years.  The 100HP Rotax has the higher torque and can spin the wider and longer props with authority.



Also available for the cost of a blade change is the Sensenich high speed blades.  Whirlwind has a blade but due to Covid lockdowns in California lead time is many months.  Sensenich and Warp Drive are made in free States so production and labor issues are not a major problem for delivery at this time.  Airmaster will build you up a set of blades and ferrules ready to mount.  It will cost you but it is worth it. 



Contact: Dirk Oyen

Oyen CTR (Europe Sales and Service)

Hemelrijk 61

Heusen-Zolder

Limburg 3550

Belgium



E: dirk.oyen1(at)telenet.be

M: +32 477 25 80 28



Website: www.propellor.com your European Airmaster Dealer.  He has the experience you will need to draw on in the UK (See the Airmaster Contacts section for resellers.) 



I have been happy with all the US manufactured blades in the Airmaster Hub. 

 And NO, you personally can't change the blades yourself.



Best Regards,

Bud Yerly

US Airmaster Dealer

Monoman

Joined: 01 Nov 2020
Posts: 22

Posted: Wed Dec 29, 2021 2:21 am Post subject: Propeller Sizing

Thanks Bud for your usual excellent reply.

I have been in contact with Dirk who has indeed suggested a replacement

blade of 64" and been most helpful but the issue remains, can I fit a 64" to

a classic mono. The LAA have provided me with a spreadsheet of calculations

to determine prop tip clearance at Max AUW which I will carry out but they

were unable to find out easily if any other classics were operating with a

64" prop so this is why I asked the community if anyone was operating with

one.

Thanks for the pointer to your website I will certainly have a look.



Thanks

Mike



--

ward.t(at)xtra.co.nz
Guest

Posted: Wed Dec 29, 2021 2:45 am Post subject: Propeller Sizing

Hi Mike,

I have 64â€ prop blades on my Mono Wheel Classic #292. Prop clearance is not a problem.

With the Airmaster CSU, Rotax 912ULS 100hp, it provides excellent performance.

Upgraded to 64â€ from 62â€ after a prop strike, on recommendation from Airmaster.

Cheers,

Tim



Sent from my iPad

Tim Ward

12 Waiwetu Street, 

Fendalton, 

Christchurch, 8052

New Zealand.

ward.t(at)xtra.co.nz 

021 0640221



[quote] On 29/12/2021, at 11:29 PM, Mike <mike(at)nyumba.co.uk> wrote:

 

 ï»¿

 

 Thanks Bud for your usual excellent reply.

 I have been in contact with Dirk who has indeed suggested a replacement

 blade of 64" and been most helpful but the issue remains, can I fit a 64" to

 a classic mono. The LAA have provided me with a spreadsheet of calculations

 to determine prop tip clearance at Max AUW which I will carry out but they

 were unable to find out easily if any other classics were operating with a

 64" prop so this is why I asked the community if anyone was operating with

 one.

 Thanks for the pointer to your website I will certainly have a look.

 

 Thanks

 Mike

 

 --

Monoman

Joined: 01 Nov 2020
Posts: 22

Posted: Wed Dec 29, 2021 4:03 am Post subject: Propeller Sizing

Hello Tim

Thanks, this is what I was after the only problem is that sadly for me you are in NZ and I suppose governed by different regs!

Here in the UK we are subject to something called CS-VLA 925 (easily googled) which makes minimum prop clearance demands.

However glad to hear that you are getting good results, what brand of blades are you using?

Thanks

Mike

 

From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of timward

Sent: 29 December 2021 10:45

To: europa-list(at)matronics.com

Subject: Re: Re: Propeller Sizing

 

Hi Mike,

I have 64â€ prop blades on my Mono Wheel Classic #292. Prop clearance is not a problem.



With the Airmaster CSU, Rotax 912ULS 100hp, it provides excellent performance.



Upgraded to 64â€ from 62â€ after a prop strike, on recommendation from Airmaster.



Cheers,



Tim

Sent from my iPad

Tim Ward



12 Waiwetu Street, 



Fendalton, 



Christchurch, 8052



New Zealand.



ward.t(at)xtra.co.nz 



021 0640221



On 29/12/2021, at 11:29 PM, Mike <mike(at)nyumba.co.uk> wrote:

[quote]

ï»¿--> Europa-List message posted by: "Mike" <mike(at)nyumba.co.uk>



Thanks Bud for your usual excellent reply.

I have been in contact with Dirk who has indeed suggested a replacement

blade of 64" and been most helpful but the issue remains, can I fit a 64" to

a classic mono. The LAA have provided me with a spreadsheet of calculations

to determine prop tip clearance at Max AUW which I will carry out but they

were unable to find out easily if any other classics were operating with a

64" prop so this is why I asked the community if anyone was operating with

one.

Thanks for the pointer to your website I will certainly have a look.



Thanks

Mike



--

ward.t(at)xtra.co.nz
Guest

Posted: Wed Dec 29, 2021 10:38 am Post subject: Propeller Sizing

Hi Mike,

Propeller is:

Warp Drive 63R WDN63R

Clockwise Tractor Diameter 64â€

Pitch High 89* Low 8*

Airmaster AP332

Narrow Chord.



Would like to have the wide chord, however next time.

Cheers,

Tim



Sent from my iPad

Tim Ward

12 Waiwetu Street, 

Fendalton, 

Christchurch, 8052

New Zealand.

ward.t(at)xtra.co.nz 

021 0640221



[quote] On 30/12/2021, at 1:12 AM, Mike <mike(at)nyumba.co.uk> wrote:

 

 ï»¿

 Hello Tim

 Thanks, this is what I was after the only problem is that sadly for me you are in NZ and I suppose governed by different regs!

 Here in the UK we are subject to something called CS-VLA 925 (easily googled) which makes minimum prop clearance demands.

 However glad to hear that you are getting good results, what brand of blades are you using?

 Thanks

 Mike

  

 From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of timward

 Sent: 29 December 2021 10:45

 To: europa-list(at)matronics.com

 Subject: Re: Re: Propeller Sizing

  

 Hi Mike,

 I have 64â€ prop blades on my Mono Wheel Classic #292. Prop clearance is not a problem.

 With the Airmaster CSU, Rotax 912ULS 100hp, it provides excellent performance.

 Upgraded to 64â€ from 62â€ after a prop strike, on recommendation from Airmaster.

 Cheers,

 Tim

 

 Sent from my iPad

 Tim Ward

 12 Waiwetu Street, 

 Fendalton, 

 Christchurch, 8052

 New Zealand.

 ward.t(at)xtra.co.nz 

 021 0640221

 

 

 On 29/12/2021, at 11:29 PM, Mike <mike(at)nyumba.co.uk> wrote:

 

 ï»¿

 

 Thanks Bud for your usual excellent reply.

 I have been in contact with Dirk who has indeed suggested a replacement

 blade of 64" and been most helpful but the issue remains, can I fit a 64" to

 a classic mono. The LAA have provided me with a spreadsheet of calculations

 to determine prop tip clearance at Max AUW which I will carry out but they

 were unable to find out easily if any other classics were operating with a

 64" prop so this is why I asked the community if anyone was operating with

 one.

 Thanks for the pointer to your website I will certainly have a look.

 

 Thanks

 Mike

 

 --

ward.t(at)xtra.co.nz
Guest

Posted: Wed Dec 29, 2021 10:40 am Post subject: Propeller Sizing

See:



https://warpdriveinc.com/product/3-blade-prop-std-hub/



Sent from my iPad

Tim Ward

12 Waiwetu Street, 

Fendalton, 

Christchurch, 8052

New Zealand.

ward.t(at)xtra.co.nz 

021 0640221



[quote] On 30/12/2021, at 1:12 AM, Mike <mike(at)nyumba.co.uk> wrote:

 

 ï»¿

 Hello Tim

 Thanks, this is what I was after the only problem is that sadly for me you are in NZ and I suppose governed by different regs!

 Here in the UK we are subject to something called CS-VLA 925 (easily googled) which makes minimum prop clearance demands.

 However glad to hear that you are getting good results, what brand of blades are you using?

 Thanks

 Mike

  

 From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of timward

 Sent: 29 December 2021 10:45

 To: europa-list(at)matronics.com

 Subject: Re: Re: Propeller Sizing

  

 Hi Mike,

 I have 64â€ prop blades on my Mono Wheel Classic #292. Prop clearance is not a problem.

 With the Airmaster CSU, Rotax 912ULS 100hp, it provides excellent performance.

 Upgraded to 64â€ from 62â€ after a prop strike, on recommendation from Airmaster.

 Cheers,

 Tim

 

 Sent from my iPad

 Tim Ward

 12 Waiwetu Street, 

 Fendalton, 

 Christchurch, 8052

 New Zealand.

 ward.t(at)xtra.co.nz 

 021 0640221

 

 

 On 29/12/2021, at 11:29 PM, Mike <mike(at)nyumba.co.uk> wrote:

 

 ï»¿

 

 Thanks Bud for your usual excellent reply.

 I have been in contact with Dirk who has indeed suggested a replacement

 blade of 64" and been most helpful but the issue remains, can I fit a 64" to

 a classic mono. The LAA have provided me with a spreadsheet of calculations

 to determine prop tip clearance at Max AUW which I will carry out but they

 were unable to find out easily if any other classics were operating with a

 64" prop so this is why I asked the community if anyone was operating with

 one.

 Thanks for the pointer to your website I will certainly have a look.

 

 Thanks

 Mike

 

 --

davidjoyce(at)doctors.org
Guest

Posted: Wed Dec 29, 2021 12:47 pm Post subject: Propeller Sizing

Mike, for what it is worth I have a Woodcomp 1625mm (=62&rdquo; as near as dammit) prop on my 914XS mono. I am not aware of prop limitations differing between Classic and XS. I have always understood that this was the max size that the LAA would approve. The clearance is fine on hard runways, but on roughish grass strips you wouldn&rsquo;t want any longer blades than that, as you might find the tips getting stained green. Regards, David Joyce, GXSDJ  

 

 

On 2021-12-29 12:03, Mike wrote: [quote]  (at)font-face 	{font-family:Calibri; 	panose-1:2 15 5 2 2 2 4 3 2 4;} (at)font-face 	{font-family:Tahoma; 	panose-1:2 11 6 4 3 5 4 4 2 4;}  #replybody1 p.v1MsoNormal, #replybody1 li.v1MsoNormal, #replybody1 div.v1MsoNormal 	{margin:0cm; 	margin-bottom:.0001pt; 	font-size:12.0pt; 	font-family:"Times New Roman","serif";} #replybody1 a:link, #replybody1 span.v1MsoHyperlink 	{mso-style-priority:99; 	color:blue; 	text-decoration:underline;} #replybody1 a:visited, #replybody1 span.v1MsoHyperlinkFollowed 	{mso-style-priority:99; 	color:purple; 	text-decoration:underline;} #replybody1 span.v1EmailStyle17 	{mso-style-type:personal-reply; 	font-family:"Calibri","sans-serif"; 	color:#1F497D;} #replybody1 .v1MsoChpDefault 	{mso-style-type:export-only; 	font-size:10.0pt;} (at)page WordSection1 	{size:612.0pt 792.0pt; 	margin:72.0pt 72.0pt 72.0pt 72.0pt;} #replybody1 div.v1WordSection1 	{page: unset;}   

Hello Tim 

Thanks, this is what I was after the only problem is that sadly for me you are in NZ and I suppose governed by different regs! 

Here in the UK we are subject to something called CS-VLA 925 (easily googled) which makes minimum prop clearance demands. 

However glad to hear that you are getting good results, what brand of blades are you using? 

Thanks 

Mike 

    

From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of timwardSent: 29 December 2021 10:45To: europa-list(at)matronics.comSubject: Re: Re: Propeller Sizing 

 

 

  

Hi Mike,  

I have 64" prop blades on my Mono Wheel Classic #292. Prop clearance is not a problem. 

  

With the Airmaster CSU, Rotax 912ULS 100hp, it provides excellent performance. 

  

Upgraded to 64" from 62" after a prop strike, on recommendation from Airmaster. 

  

Cheers, 

  

Tim  

Sent from my iPad  

Tim Ward 

  

12 Waiwetu Street,  

  

Fendalton,  

  

Christchurch, 8052 

  

New Zealand. 

  

ward.t(at)xtra.co.nz  

  

021 0640221 

 

  

 

On 29/12/2021, at 11:29 PM, Mike <mike(at)nyumba.co.uk> wrote: 

 [quote]  

--> Europa-List message posted by: "Mike" <mike(at)nyumba.co.uk>Thanks Bud for your usual excellent reply.I have been in contact with Dirk who has indeed suggested a replacementblade of 64" and been most helpful but the issue remains, can I fit a 64" toa classic mono. The LAA have provided me with a spreadsheet of calculationsto determine prop tip clearance at Max AUW which I will carry out but theywere unable to find out easily if any other classics were operating with a64" prop so this is why I asked the community if anyone was operating withone.Thanks for the pointer to your website I will certainly have a look.ThanksMike--

budyerly@msn.com

Joined: 05 Oct 2019
Posts: 288
Location: Florida USA

Posted: Wed Dec 29, 2021 2:05 pm Post subject: Propeller Sizing

Mike, 

The 64 inch prop is the blade length ideal for all versions of the 912ULS and 914 equipped on the Europa Classic/XS/Mono/Trigear.  It has the recommended ground clearance for normal operations for the mono and trigear.  Propeller manufacturers know the max length for each of their blades to meet the Rotax moment of inertia, bolt pattern and other factors.  I’ve placed a 64 inch wide chord Warp on a 80HP Rotax and it just wouldn’t turn it up to speed and top end cruise suffered.  So max length is based on engine torque. 

  

Notes: 

Warp Drive is comfortable with the Wide Chord (Standard) blade on high speed aircraft from 64 to 67 inches.  I’ve seen guys with 70 inch two blade Warp Drive props on a Kitfox with a 912UL 80HP engine and the blade pitch at the tip is flat.   

  

Each propeller manufacturer will have recommended lengths for each of the aircraft / engine combinations.  Airmaster is one of the few to actually print the lengths on their website by aircraft type and powerplant. 

  

The 64 inch Warp/Sensenich/Whirlwind is what all of us put on the Europa and is the only length we recommend for the Europa 912ULS/914.  The speed decrease at cruise is only a knot slower for the 64 inch and the ground clearance is in the ideal range.   

  

In the paper I wrote on What propeller blade length and hub was ideal for the Rotax engines, I commented that with most propellers of  a 16 to22 degrees of root to tip twist the length and pitch of the prop was calculated for lengths from 64 inches out to 75.  For fast airplanes (like the Europa) nothing good happens after 67 to 68 inches.  Inertia goes up (Warp Drive blades have high inertia) and lighter wood and composite props can be longer, but at a speed penalty so I set the and had many prop builders hate me for recommending “Nothing good happens after 68 inches on a constant speed  prop on a Rotax engine in my opinion.”  Sure, one can thin the tip way down or sweep it and get another inch per blade, but generally speaking 67 with a warp, 68-70 with a Whirlwind and some Sensenich with the highly swept  tips (scimitar shape) rather than the round or square tips. 

  

The definition of ideal prop length I have in my files for many other aircraft are:  Ground clearance. There must be a clearance of at least seven inches (for each airplane with nose wheel  landing gear) or nine inches (for each airplane with tail wheel landing gear) between each propeller and the ground with the landing gear statically deflected and in the level, normal takeoff, or taxing attitude, whichever is most critical. In addition, for each airplane with conventional landing gear struts using fluid or mechanical means for absorbing landing shocks, there must be positive clearance between  the propeller and the ground in the level takeoff attitude with the critical tire completely deflated and the corresponding landing gear strut bottomed. Positive clearance for airplanes using leaf spring struts is shown with a deflection corresponding to 1.5  g.   

In the mono, the rubber block has a slant in it which when compressed stops the gear deflection and will allow  the mono in level flight attitude to meet this 7 inch propeller clearance. 

  

Best Regards, 

Bud Yerly 

  

--

Paul M 383

Joined: 19 Mar 2012
Posts: 97
Location: United Kingdom

Posted: Wed Dec 29, 2021 2:22 pm Post subject: Propeller Sizing

I'm sure that was a typo, but 1625mm = 63.98". ðŸ‘ðŸ˜‡ðŸ¤“ 

 

 I have the same (LAA approved) blades on my 912S XS mono and the only factors I could think that would differ on a Classic would be engine (and therefore spinner) height and tailwheel length/positon.

 

 

 I'll measure my spinner tip height above ground tomorrow ðŸ‘

 

 

 HTH,

 Paul M

 G-PLPM

 

 

 

 

 -------- Original message --------

 From: davidjoyce(at)doctors.org.uk 

 Date: 29/12/2021 20:51 (GMT+00:00) 

 To: europa-list(at)matronics.com 

 Subject: Re: Europa-List: Re: Propeller Sizing 

 

 

  

Mike, for what it is worth I have a Woodcomp 1625mm (=62â€ as near as dammit) prop on my 914XS mono. I am not aware of prop limitations differing between Classic and XS. I have always understood that this was the max size that the LAA would approve. The clearance  is fine on hard runways, but on roughish grass strips you wouldnâ€™t want any longer blades than that, as you might find the tips getting stained green. Regards, David Joyce, GXSDJ  

 



  

On 2021-12-29 12:03, Mike wrote: [quote]      

Hello Tim 

Thanks, this is what I was after the only problem is that sadly for me you are in NZ and I suppose governed by different regs! 

Here in the UK we are subject to something called CS-VLA 925 (easily googled) which makes minimum prop clearance demands. 

However glad to hear that you are getting good results, what brand of blades are you using? 

Thanks 

Mike 

    

From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of timward

 Sent: 29 December 2021 10:45

 To: europa-list(at)matronics.com

 Subject: Re: Europa-List: Re: Propeller Sizing 

 

 

  

Hi Mike,  

I have 64" prop blades on my Mono Wheel Classic #292. Prop clearance is not a problem. 

  

With the Airmaster CSU, Rotax 912ULS 100hp, it provides excellent performance. 

  

Upgraded to 64" from 62" after a prop strike, on recommendation from Airmaster. 

  

Cheers, 

  

Tim  

Sent from my iPad  

Tim Ward 

  

12 Waiwetu Street,  

  

Fendalton,  

  

Christchurch, 8052 

  

New Zealand. 

  

ward.t(at)xtra.co.nz  

  

021 0640221 

 

  



 

  

On 29/12/2021, at 11:29 PM, Mike <mike(at)nyumba.co.uk> wrote: 

 [quote]  

--> Europa-List message posted by: "Mike" <mike(at)nyumba.co.uk>

 

 Thanks Bud for your usual excellent reply.

 I have been in contact with Dirk who has indeed suggested a replacement

 blade of 64" and been most helpful but the issue remains, can I fit a 64" to

 a classic mono. The LAA have provided me with a spreadsheet of calculations

 to determine prop tip clearance at Max AUW which I will carry out but they

 were unable to find out easily if any other classics were operating with a

 64" prop so this is why I asked the community if anyone was operating with

 one.

 Thanks for the pointer to your website I will certainly have a look.

 

 Thanks

 Mike

 

 --

budyerly@msn.com

Joined: 05 Oct 2019
Posts: 288
Location: Florida USA

Posted: Wed Dec 29, 2021 2:42 pm Post subject: Propeller Sizing

David, 

The Woodcomp has a larger twist hence it varies in exact length at the props  are made from 1600 (63â€) to  1738mm (68â€).  Woodcomp uses a 1600mm blade for the Europa on their SR3000.  On the Airmaster, the actual blade length will vary from the  64 inch maximum based on the production mold used down slightly after production.  For instance, at Woodcomp they donâ€™t cut a 1700 mm prop down to 1600.  That is a different mold so measuring the prop provided will not always be exact.  64 inches maximum meets the criteria for the UK and US with the black rubber block (as the regs are basically the same).  Europa 2004, Airmaster and I have supplied many props (even fixed pitch) at 64 inches per the LAA.  (Letâ€™s face it, it is only an inch longer at the tip than yours.)  The Europa Club website indicates that the Airmaster was considered to be the â€œstandardâ€ for the Europa.   They are all nominally 62-64â€ maximum length.  Unfortunately, the Europa Factory POH from 1998 still says 62 inches in the performance numbers because the original engine was the 912.   Those figures are based on the narrow chord blade.  Note, from my reading of the original test flights the fixed prop was set to a takeoff static RPM of 4000 for cruise and 5500 for takeoff for testing like most Rotax powered kit planes trick us with.  Note the tip is really set high at 21degrees for the 912S.  The 912S with the wide chord give better performance from takeoff to cruise. 

  

Iâ€™m forced to say that all our 64 inch props are not exactly 64 inch blade lengths after mounting in the rotating barrel of a constant speed prop.  It seems there are no absolutes in aviation.  By the time the blades are ground to length, shaped and balanced, each prop is slightly different in length. 

  

Best Regards, 

Bud Yerly   

From: owner-europa-list-server(at)matronics.com  <owner-europa-list-server(at)matronics.com> On Behalf Of davidjoyce(at)doctors.org.uk

 Sent: Wednesday, December 29,  2021 3:47 PM

 To: europa-list(at)matronics.com

 Subject: Re: Europa-List: Re: Propeller Sizing 

 

 

  

Mike, for what it is worth I have a Woodcomp 1625mm (=62â€ as near as dammit) prop on my 914XS mono. I am not aware of prop limitations differing between Classic  and XS. I have always understood that this was the max size that the LAA would approve. The clearance is fine on hard runways, but on roughish grass strips you wouldnâ€™t want any longer blades than that, as you might find the tips getting stained green. Regards,  David Joyce, GXSDJ  

  

 

  

On 2021-12-29 12:03, Mike wrote: [quote]    

Hello Tim 

Thanks, this is what I was after the only problem is that sadly for me you are in NZ and I suppose governed  by different regs! 

Here in the UK we are subject to something called CS-VLA 925 (easily googled) which makes minimum prop clearance  demands. 

However glad to hear that you are getting good results, what brand of blades are you using? 

Thanks 

Mike 

    

[b]From:[/b] owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com) [mailto:owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com)] [b]On Behalf Of [/b]timward

 [b]Sent:[/b] 29 December 2021 10:45

 [b]To:[/b] europa-list(at)matronics.com (europa-list(at)matronics.com)

 [b]Subject:[/b] Re: Europa-List: Re: Propeller Sizing 

 

 

  

Hi Mike,  

I have 64" prop blades on my Mono Wheel Classic #292. Prop clearance is not a problem. 

  

With the Airmaster CSU, Rotax 912ULS 100hp, it provides excellent performance. 

  

Upgraded to 64" from 62" after a prop strike, on recommendation from Airmaster. 

  

Cheers, 

  

Tim  

Sent from my iPad  

Tim Ward 

  

12 Waiwetu Street,  

  

Fendalton,  

  

Christchurch, 8052 

  

New Zealand. 

  

ward.t(at)xtra.co.nz (ward.t(at)xtra.co.nz)  

  

021 0640221 

 

  

  

On 29/12/2021, at 11:29 PM, Mike <mike(at)nyumba.co.uk (mike(at)nyumba.co.uk)>  wrote: 

 [quote]  

--> Europa-List message posted by: "Mike" <mike(at)nyumba.co.uk (mike(at)nyumba.co.uk)>

 

 Thanks Bud for your usual excellent reply.

 I have been in contact with Dirk who has indeed suggested a replacement

 blade of 64" and been most helpful but the issue remains, can I fit a 64" to

 a classic mono. The LAA have provided me with a spreadsheet of calculations

 to determine prop tip clearance at Max AUW which I will carry out but they

 were unable to find out easily if any other classics were operating with a

 64" prop so this is why I asked the community if anyone was operating with

 one.

 Thanks for the pointer to your website I will certainly have a look.

 

 Thanks

 Mike

 

 --

davidjoyce(at)doctors.org
Guest

Posted: Wed Dec 29, 2021 6:58 pm Post subject: Propeller Sizing

Thanks Paul, it was indeed a typo. I meant as near as dammit 64&rdquo;. David  

 

 

On 2021-12-29 22:21, Paul Mansfield wrote: [quote]  I'm sure that was a typo, but 1625mm = 63.98". ðŸ‘ðŸ˜‡ðŸ¤“  

 I have the same (LAA approved) blades on my 912S XS mono and the only factors I could think that would differ on a Classic would be engine (and therefore spinner) height and tailwheel length/positon.

  

 I'll measure my spinner tip height above ground tomorrow ðŸ‘

  

 HTH,

 Paul M

 G-PLPM

  

  

 -------- Original message --------

 From: davidjoyce(at)doctors.org.uk

 Date: 29/12/2021 20:51 (GMT+00:00)

 To: europa-list(at)matronics.com

 Subject: Re: Re: Propeller Sizing

  

  

Mike, for what it is worth I have a Woodcomp 1625mm (=62" as near as dammit) prop on my 914XS mono. I am not aware of prop limitations differing between Classic and XS. I have always understood that this was the max size that the LAA would approve. The clearance is fine on hard runways, but on roughish grass strips you wouldn't want any longer blades than that, as you might find the tips getting stained green. Regards, David Joyce, GXSDJ  

 

 

On 2021-12-29 12:03, Mike wrote: [quote]  (at)font-face 	{font-family:Calibri} (at)font-face 	{font-family:Tahoma} #replybody1 #v1replybody1 p.v1v1MsoNormal, #replybody1 #v1replybody1 li.v1v1MsoNormal, #replybody1 #v1replybody1 div.v1v1MsoNormal 	{margin:0cm; 	margin-bottom:.0001pt; 	font-size:12.0pt; 	font-family:"Times New Roman","serif"} #replybody1 #v1replybody1 a:link, #replybody1 #v1replybody1 span.v1v1MsoHyperlink 	{color:blue; 	text-decoration:underline} #replybody1 #v1replybody1 a:visited, #replybody1 #v1replybody1 span.v1v1MsoHyperlinkFollowed 	{color:purple; 	text-decoration:underline} #replybody1 #v1replybody1 span.v1v1EmailStyle17 	{font-family:"Calibri","sans-serif"; 	color:#1F497D} #replybody1 #v1replybody1 .v1v1MsoChpDefault 	{font-size:10.0pt} (at)page WordSection1 	{margin:72.0pt 72.0pt 72.0pt 72.0pt} #replybody1 #v1replybody1 div.v1v1WordSection1 	{}   

Hello Tim 

Thanks, this is what I was after the only problem is that sadly for me you are in NZ and I suppose governed by different regs! 

Here in the UK we are subject to something called CS-VLA 925 (easily googled) which makes minimum prop clearance demands. 

However glad to hear that you are getting good results, what brand of blades are you using? 

Thanks 

Mike 

    

From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of timwardSent: 29 December 2021 10:45To: europa-list(at)matronics.comSubject: Re: Re: Propeller Sizing 

 

 

  

Hi Mike,  

I have 64" prop blades on my Mono Wheel Classic #292. Prop clearance is not a problem. 

  

With the Airmaster CSU, Rotax 912ULS 100hp, it provides excellent performance. 

  

Upgraded to 64" from 62" after a prop strike, on recommendation from Airmaster. 

  

Cheers, 

  

Tim  

Sent from my iPad  

Tim Ward 

  

12 Waiwetu Street,  

  

Fendalton,  

  

Christchurch, 8052 

  

New Zealand. 

  

ward.t(at)xtra.co.nz  

  

021 0640221 

 

  

 

On 29/12/2021, at 11:29 PM, Mike <mike(at)nyumba.co.uk> wrote: 

 [quote]  

--> Europa-List message posted by: "Mike" <mike(at)nyumba.co.uk>Thanks Bud for your usual excellent reply.I have been in contact with Dirk who has indeed suggested a replacementblade of 64" and been most helpful but the issue remains, can I fit a 64" toa classic mono. The LAA have provided me with a spreadsheet of calculationsto determine prop tip clearance at Max AUW which I will carry out but theywere unable to find out easily if any other classics were operating with a64" prop so this is why I asked the community if anyone was operating withone.Thanks for the pointer to your website I will certainly have a look.ThanksMike--

davidjoyce(at)doctors.org
Guest

Posted: Wed Dec 29, 2021 7:03 pm Post subject: Propeller Sizing

Bud, Possibly the earlier versions of the SR3000 were 1600mm but my more recent SR3000 N W comes with its certificate stating 1625mm, or 64 ins as corrected by Paul. Regards, David 

 

On 2021-12-29 22:42, Bud Yerly wrote: [quote]  (at)font-face 	{font-family:"Cambria Math"; 	panose-1:2 4 5 3 5 4 6 3 2 4; 	mso-font-charset:0; 	mso-generic-font-family:roman; 	mso-font-pitch:variable; 	mso-font-signature:3 0 0 0 1 0} (at)font-face 	{font-family:Calibri; 	panose-1:2 15 5 2 2 2 4 3 2 4; 	mso-font-charset:0; 	mso-generic-font-family:swiss; 	mso-font-pitch:variable; 	mso-font-signature:-469750017 -1073732485 9 0 511 0} (at)font-face 	{font-family:Verdana; 	panose-1:2 11 6 4 3 5 4 4 2 4; 	mso-font-charset:0; 	mso-generic-font-family:swiss; 	mso-font-pitch:variable; 	mso-font-signature:-1610610945 1073750107 16 0 415 0} (at)font-face 	{font-family:Tahoma; 	panose-1:2 11 6 4 3 5 4 4 2 4; 	mso-font-charset:0; 	mso-generic-font-family:swiss; 	mso-font-pitch:variable; 	mso-font-signature:-520081665 -1073717157 41 0 66047 0}  #v1replybody1 p.v1v1MsoNormal, #v1replybody1 li.v1v1MsoNormal, #v1replybody1 div.v1v1MsoNormal 	{mso-style-unhide:no; 	mso-style-qformat:yes; 	mso-style-parent:""; 	margin:0in; 	mso-pagination:widow-orphan; 	font-size:11.0pt; 	font-family:"Calibri",sans-serif; 	mso-fareast-font-family:Calibri} #v1replybody1 a:link, #v1replybody1 span.v1v1MsoHyperlink 	{mso-style-priority:99; 	color:blue; 	text-decoration:underline; 	text-underline:single} #v1replybody1 a:visited, #v1replybody1 span.v1v1MsoHyperlinkFollowed 	{mso-style-noshow:yes; 	mso-style-priority:99; 	color:purple; 	text-decoration:underline; 	text-underline:single} #v1replybody1 p.v1v1msonormal0, #v1replybody1 li.v1v1msonormal0, #v1replybody1 div.v1v1msonormal0 	{mso-style-name:msonormal; 	mso-style-unhide:no; 	mso-margin-top-alt:auto; 	margin-right:0in; 	mso-margin-bottom-alt:auto; 	margin-left:0in; 	mso-pagination:widow-orphan; 	font-size:11.0pt; 	font-family:"Calibri",sans-serif; 	mso-fareast-font-family:Calibri} #v1replybody1 p.v1v1v1msonormal, #v1replybody1 li.v1v1v1msonormal, #v1replybody1 div.v1v1v1msonormal 	{mso-style-name:v1msonormal; 	mso-style-unhide:no; 	mso-margin-top-alt:auto; 	margin-right:0in; 	mso-margin-bottom-alt:auto; 	margin-left:0in; 	mso-pagination:widow-orphan; 	font-size:11.0pt; 	font-family:"Calibri",sans-serif; 	mso-fareast-font-family:Calibri} #v1replybody1 p.v1v1v1msochpdefault, #v1replybody1 li.v1v1v1msochpdefault, #v1replybody1 div.v1v1v1msochpdefault 	{mso-style-name:v1msochpdefault; 	mso-style-unhide:no; 	mso-margin-top-alt:auto; 	margin-right:0in; 	mso-margin-bottom-alt:auto; 	margin-left:0in; 	mso-pagination:widow-orphan; 	font-size:11.0pt; 	font-family:"Calibri",sans-serif; 	mso-fareast-font-family:Calibri} #v1replybody1 span.v1v1v1msohyperlink 	{mso-style-name:v1msohyperlink; 	mso-style-unhide:no} #v1replybody1 span.v1v1v1msohyperlinkfollowed 	{mso-style-name:v1msohyperlinkfollowed; 	mso-style-unhide:no} #v1replybody1 span.v1v1v1emailstyle17 	{mso-style-name:v1emailstyle17; 	mso-style-unhide:no} #v1replybody1 p.v1v1v1msonormal1, #v1replybody1 li.v1v1v1msonormal1, #v1replybody1 div.v1v1v1msonormal1 	{mso-style-name:v1msonormal1; 	mso-style-unhide:no; 	margin:0in; 	mso-pagination:widow-orphan; 	font-size:12.0pt; 	font-family:"Times New Roman",serif; 	mso-fareast-font-family:Calibri} #v1replybody1 p.v1v1v1msonormal2, #v1replybody1 li.v1v1v1msonormal2, #v1replybody1 div.v1v1v1msonormal2 	{mso-style-name:v1msonormal2; 	mso-style-unhide:no; 	margin:0in; 	mso-pagination:widow-orphan; 	font-size:12.0pt; 	font-family:"Times New Roman",serif; 	mso-fareast-font-family:Calibri} #v1replybody1 span.v1v1v1msohyperlink1 	{mso-style-name:v1msohyperlink1; 	mso-style-priority:99; 	mso-style-unhide:no; 	color:blue; 	text-decoration:underline; 	text-underline:single} #v1replybody1 span.v1v1v1msohyperlinkfollowed1 	{mso-style-name:v1msohyperlinkfollowed1; 	mso-style-priority:99; 	mso-style-unhide:no; 	color:purple; 	text-decoration:underline; 	text-underline:single} #v1replybody1 span.v1v1EmailStyle28 	{mso-style-type:personal; 	mso-style-noshow:yes; 	mso-style-unhide:no; 	font-family:"Calibri",sans-serif; 	mso-ascii-font-family:Calibri; 	mso-hansi-font-family:Calibri; 	mso-bidi-font-family:Calibri; 	color:#1F497D} #v1replybody1 span.v1v1EmailStyle31 	{mso-style-type:personal-reply; 	mso-style-noshow:yes; 	mso-style-unhide:no; 	mso-ansi-font-size:11.0pt; 	mso-bidi-font-size:11.0pt; 	font-family:"Calibri",sans-serif; 	mso-ascii-font-family:Calibri; 	mso-fareast-font-family:Calibri; 	mso-hansi-font-family:Calibri; 	mso-bidi-font-family:"Times New Roman"; 	color:windowtext} #v1replybody1 span.v1v1GramE 	{mso-style-name:""; 	mso-gram-e:yes} #v1replybody1 .v1v1MsoChpDefault 	{mso-style-type:export-only; 	mso-default-props:yes; 	font-size:10.0pt; 	mso-ansi-font-size:10.0pt; 	mso-bidi-font-size:10.0pt} (at)page WordSection1 	{size:8.5in 11.0in; 	margin:1.0in 1.0in 1.0in 1.0in; 	mso-header-margin:.5in; 	mso-footer-margin:.5in; 	mso-paper-source:0} #v1replybody1 div.v1v1WordSection1 	{page: unset}   

David, 

The Woodcomp has a larger twist hence it varies in exact length at the props are made from 1600 (63") to  1738mm (68").  Woodcomp uses a 1600mm blade for the Europa on their SR3000.  On the Airmaster, the actual blade length will vary from the  64 inch maximum based on the production mold used down slightly after production.  For instance, at Woodcomp they don't cut a 1700 mm prop down to 1600.  That is a different mold so measuring the prop provided will not always be exact.  64 inches maximum meets the criteria for the UK and US with the black rubber block (as the regs are basically the same).  Europa 2004, Airmaster and I have supplied many props (even fixed pitch) at 64 inches per the LAA.  (Let's face it, it is only an inch longer at the tip than yours.)  The Europa Club website indicates that the Airmaster was considered to be the "standard" for the Europa.   They are all nominally 62-64" maximum length.  Unfortunately, the Europa Factory POH from 1998 still says 62 inches in the performance numbers because the original engine was the 912.   Those figures are based on the narrow chord blade.  Note, from my reading of the original test flights the fixed prop was set to a takeoff static RPM of 4000 for cruise and 5500 for takeoff for testing like most Rotax powered kit planes trick us with.  Note the tip is really set high at 21degrees for the 912S.  The 912S with the wide chord give better performance from takeoff to cruise. 

  

I'm forced to say that all our 64 inch props are not exactly 64 inch blade lengths after mounting in the rotating barrel of a constant speed prop.  It seems there are no absolutes in aviation.  By the time the blades are ground to length, shaped and balanced, each prop is slightly different in length. 

  

Best Regards, 

Bud Yerly   

From: owner-europa-list-server(at)matronics.com <owner-europa-list-server(at)matronics.com> On Behalf Of davidjoyce(at)doctors.org.ukSent: Wednesday, December 29,  2021 3:47 PMTo: europa-list(at)matronics.comSubject: Re: Re: Propeller Sizing 

 

 

  

Mike, for what it is worth I have a Woodcomp 1625mm (=62" as near as dammit) prop on my 914XS mono. I am not aware of prop limitations differing between Classic and XS. I have always understood that this was the max size that the LAA would approve. The clearance is fine on hard runways, but on roughish grass strips you wouldn't want any longer blades than that, as you might find the tips getting stained green. Regards, David Joyce, GXSDJ  

  

 

  

On 2021-12-29 12:03, Mike wrote: [quote]    

Hello Tim 

Thanks, this is what I was after the only problem is that sadly for me you are in NZ and I suppose governed by different regs! 

Here in the UK we are subject to something called CS-VLA 925 (easily googled) which makes minimum prop clearance demands. 

However glad to hear that you are getting good results, what brand of blades are you using? 

Thanks 

Mike 

    

[b]From:[/b] owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com) [mailto:owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com)] [b]On Behalf Of [/b]timward[b]Sent:[/b] 29 December 2021 10:45[b]To:[/b] europa-list(at)matronics.com (europa-list(at)matronics.com)[b]Subject:[/b] Re: Re: Propeller Sizing 

 

 

  

Hi Mike,  

I have 64" prop blades on my Mono Wheel Classic #292. Prop clearance is not a problem. 

  

With the Airmaster CSU, Rotax 912ULS 100hp, it provides excellent performance. 

  

Upgraded to 64" from 62" after a prop strike, on recommendation from Airmaster. 

  

Cheers, 

  

Tim  

Sent from my iPad  

Tim Ward 

  

12 Waiwetu Street,  

  

Fendalton,  

  

Christchurch, 8052 

  

New Zealand. 

  

ward.t(at)xtra.co.nz (ward.t(at)xtra.co.nz)  

  

021 0640221 

 

  

  

On 29/12/2021, at 11:29 PM, Mike <mike(at)nyumba.co.uk (mike(at)nyumba.co.uk)> wrote: 

 [quote]  

--> Europa-List message posted by: "Mike" <mike(at)nyumba.co.uk (mike(at)nyumba.co.uk)>Thanks Bud for your usual excellent reply.I have been in contact with Dirk who has indeed suggested a replacementblade of 64" and been most helpful but the issue remains, can I fit a 64" toa classic mono. The LAA have provided me with a spreadsheet of calculationsto determine prop tip clearance at Max AUW which I will carry out but theywere unable to find out easily if any other classics were operating with a64" prop so this is why I asked the community if anyone was operating withone.Thanks for the pointer to your website I will certainly have a look.ThanksMike--

Monoman

Joined: 01 Nov 2020
Posts: 22

Posted: Thu Dec 30, 2021 2:02 am Post subject: Propeller Sizing

Hello All

Wow, I have just seen the many replies received from last night, I am slightly embarrassed at taking over the forum at least temporarily. Thank you all for taking the time to reply, I will try to be brief in setting out where I think I am.

As I mentioned I have been asked by the LAA to carry out the measurements to comply with CS-VLA 925 which is essentially what Bud outlines in his last paragraph (and thanks again Bud for your input, I intend forwarding your replies to the LAA if you don’t mind?).However at the moment I am bound by the rules here in the UK but hopefully Bud your comments will help. By the way I think that you meant 9” in your last sentence? 

As some of you have pointed out the XS set up has the engine slightly higher and further forward than the classic so should provide greater clearance so I was only interested to see if any other fully classic mono aircraft (UK regulated, I should have said this in my original request) had fitted a 64” prop.

It seems that Tim in NZ is the only one so far to have done it but sadly it didn’t help for a UK based aircraft (but good to hear that it works).

I must say that I am surprised that this doesn’t seem to have been an issue here in the UK before as most of the classics must surely have been Mono’s?

So at present my aircraft is wings off in my workshop at home having the engine replaced and I will now re fit the wings and carry out the weighing versus clearance measurements and submit them to the LAA. As the lead time for replacement blades is currently in excess of 3 months I am thinking that maybe I will re fit the original prop (however unsuitable) at least to keep me flying until possible new blades arrive.

Thank you all for your inputs on this so far, I would still be interested to hear from any UK based Classic mono owners that might have a 64” prop fitted.

 

Cheers

Mike 

 

From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of Bud Yerly

Sent: 29 December 2021 22:05

To: europa-list(at)matronics.com; mike(at)nyumba.co.uk

Subject: RE: Re: Propeller Sizing

 

Mike,

The 64 inch prop is the blade length ideal for all versions of the 912ULS and 914 equipped on the Europa Classic/XS/Mono/Trigear.  It has the recommended ground clearance for normal operations for the mono and trigear.  Propeller manufacturers know the max length for each of their blades to meet the Rotax moment of inertia, bolt pattern and other factors.  I’ve placed a 64 inch wide chord Warp on a 80HP Rotax and it just wouldn’t turn it up to speed and top end cruise suffered.  So max length is based on engine torque.

 

Notes:

Warp Drive is comfortable with the Wide Chord (Standard) blade on high speed aircraft from 64 to 67 inches.  I’ve seen guys with 70 inch two blade Warp Drive props on a Kitfox with a 912UL 80HP engine and the blade pitch at the tip is flat.  

 

Each propeller manufacturer will have recommended lengths for each of the aircraft / engine combinations.  Airmaster is one of the few to actually print the lengths on their website by aircraft type and powerplant.

 

The 64 inch Warp/Sensenich/Whirlwind is what all of us put on the Europa and is the only length we recommend for the Europa 912ULS/914.  The speed decrease at cruise is only a knot slower for the 64 inch and the ground clearance is in the ideal range.  

 

In the paper I wrote on What propeller blade length and hub was ideal for the Rotax engines, I commented that with most propellers of a 16 to22 degrees of root to tip twist the length and pitch of the prop was calculated for lengths from 64 inches out to 75.  For fast airplanes (like the Europa) nothing good happens after 67 to 68 inches.  Inertia goes up (Warp Drive blades have high inertia) and lighter wood and composite props can be longer, but at a speed penalty so I set the and had many prop builders hate me for recommending “Nothing good happens after 68 inches on a constant speed prop on a Rotax engine in my opinion.”  Sure, one can thin the tip way down or sweep it and get another inch per blade, but generally speaking 67 with a warp, 68-70 with a Whirlwind and some Sensenich with the highly swept tips (scimitar shape) rather than the round or square tips.

 

The definition of ideal prop length I have in my files for many other aircraft are:

<![if !supportLists]>(a)    <![endif]>Ground clearance. There must be a clearance of at least seven inches (for each airplane with nose wheel landing gear) or nine inches (for each airplane with tail wheel landing gear) between each propeller and the ground with the landing gear statically deflected and in the level, normal takeoff, or taxing attitude, whichever is most critical. In addition, for each airplane with conventional landing gear struts using fluid or mechanical means for absorbing landing shocks, there must be positive clearance between the propeller and the ground in the level takeoff attitude with the critical tire completely deflated and the corresponding landing gear strut bottomed. Positive clearance for airplanes using leaf spring struts is shown with a deflection corresponding to 1.5 g.  

In the mono, the rubber block has a slant in it which when compressed stops the gear deflection and will allow the mono in level flight attitude to meet this 7 inch propeller clearance.

 

Best Regards,

Bud Yerly

 

--

Dave Disney

Joined: 16 Aug 2010
Posts: 54
Location: Weston-Super-Mare

Posted: Thu Dec 30, 2021 4:41 am Post subject: Re: Propeller Sizing

Hi Mike,



A couple of suggestions for you.



1. see if you can get hold of a copy of the original approved propeller list, the LAA might help with this. If I remember correctly it had some individual a/c registrations with engine and prop set-up. If one of them has the same set-up that you propose and it's on a mono (either classic or XS) then you should be good to go.



2. It seems that the LAA are worried that your ground clearance may not meet CS-VLA because of the hub/blade combination. One way around this may be to ask someone who has the Airmaster 332 hub with Warp Drive 64 inch blades to measure the actual diameter of the blades as installed. This comparison may satisfy the LAA that CS-VLA is being met. 



3. Look back through the old 'Europa Flyer' and probably better 'Tech Talk' publications on the Europa Club web site, there may be an article describing what you want to do as further 'evidence' that it's been done before.

budyerly@msn.com

Joined: 05 Oct 2019
Posts: 288
Location: Florida USA

Posted: Thu Dec 30, 2021 9:37 am Post subject: Propeller Sizing

David, Tim and group.

Sorry for the slow response.  Anita and I are recovering from our flu/covid/omicron/delta “breakthrough” cases.  So, just a case of the flu for us and simple over the counter medication keeps the symptoms in check.  Not worth standing in line with the masses of travelers, government contract workers and New Yorkers down here worried about their job or getting the Covid from us Floridians.  (Anita and I believe we had Covid at New Years 2020 like many did in our area (there was no testing for antibodies available then), but we got the Covid shots “vaccine” and we still got the flu/omicron of course.)  Neither of us is normally affected much by the flu variations over the years other than just feeling under the weather for a few days, so we are lucky.



For a Mono and conventional gear aircraft, ground clearance is 9 and a trigear is 7 inch clearance at full impact clearance.  Duh.  I should have been more exact.  The actual certified standard for aircraft is uniform across the world at these values.  Of course, regulations change so check in your country.  Here are the US/International certified basic requirement guidelines.

Sec. 23.925 — Propeller clearance.

(a) Ground clearance. There must be a clearance of at least seven inches (for each airplane with nose wheel landing gear) or nine inches (for each airplane with tail wheel landing gear) between each propeller and the ground with the landing gear statically deflected and in the level, normal takeoff, or taxing attitude, whichever is most critical. In addition, for each airplane with conventional landing gear struts using fluid or mechanical means for absorbing landing shocks, there must be positive clearance between the propeller and the ground in the level takeoff attitude with the critical tire completely deflated and the corresponding landing gear strut bottomed. Positive clearance for airplanes using leaf spring struts is shown with a deflection corresponding to 1.5 g.



The Woodcomp guys just used the original certified testing standard which Airmaster met to assure they were in compliance with the LAA.



To be honest, I only got involved with the prop ground clearance when Bob Berube made his conventional conversion years ago.  The gear height was based on the 64 inch propeller with a minimum of 9 inches.



Story Time.

The gear length was set by Grove aircraft for the single beam gear and placed to give 9 inches.  Since it was a non articulated fixed beam gear leg, Grove was sure to meet the criteria required by the FAA.

If I recall correctly, the plane was loaded IAW the FAA manual to full gross weight and a three foot drop test was made to determine gear flexing, structure, and alignment.  The Grove gear slid sideways a little off the centerline of the mounts and pins were fitted as standard to prevent recurrence.  Bending of the gear at the belly of the aircraft was only enough to just touch the belly skin at the center. That was scary but I had seen it before

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