---------------------------------------------------------- Allegro-List Digest Archive --- Total Messages Posted Wed 10/31/07: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:02 AM - Re: Allegro 80 HP Woodcomp Pitch setting (TIM MOSES) 2. 07:46 PM - Re: Allegro 80 HP Woodcomp Pitch setting (hgmckay@bellsouth.net) ________________________________ Message 1 _____________________________________ Time: 07:02:19 AM PST US From: "TIM MOSES" Subject: Re: Allegro-List: Allegro 80 HP Woodcomp Pitch setting Hugh, I just got an email from the Australian Allegro/Woodcomp dealer and he said that the blade pitch is measured at "1/3 of the blade length from the tip". I thought it was customary to use the 75% blade span (ie. 1/4 of the blade length from the tip). So my question is what distance is this 14 or 15 degrees measured at? The following is the adjustment message I recieved from Michael Coats: setting up the propeller is no big deal but it must be done properly. forget the recommendations above, there is only one way to set the propeller and the instructions follow. Please note I am the Woodcomp certified service centre from Australia and New Zealand so I can tell you with certainty that the following information is correct. The correct distance the setting the blade measurement with just about every propeller ever manufactured is ***one third*** of the blade length in from the blade tip. You will see in the attached photographs I have made a very small T square which on the propeller I am using is 180 mm long, yours will be similar. In a pictures shown I am using a warp drive propeller protract which is probably the most common unit out there, is extremely cheap (approximate we $20) and will last a lifetime of normal use provided you don't drop it and break it. Step one, make sure the propeller blade is horizontal, if it is not horizontal get it is close to horizontal is you can and using a piece of wood or a broomstick or something like that marked the distance from the propeller leading edge to the ground and make sure that all of the other adjustments are made in this exact same position otherwise you will get varying blade angles. So firstly to set the propeller horizontal and then using the little T square position the propeller protract one third of the way up the propeller and take your adjustment. We mainly have cruise settings on our propeller and these follow below.... 80hp 18 degrees 100 hp 21 degrees If you want to get a bit more climb performance out of it I would suggest initially going approximately 1 1/2 degrees finer pitch, so for example on the 80 hp engine I would start at about 16.5=B0 or thereabouts than it is a simple matter of adjusting each of the three blades on the propeller to get them all identical. Tighten up all the bolts and recheck after everything has been tightened just to make sure that nothing has moved. You can leave the propeller spinner off if you wish and go for a fly making sure that the performance and blade angles suit your needs. If you find your engine is over revving or you are using too many revs to your desired cruise speed simply course in the propeller up so go from 16.5=B0 to approximately 17.5=B0 and so on. On most of these propellers 1=B0 of blade movement makes approximately 200 rpm difference as a general rule of thumb so if your aircraft is readying 400 rpm too high then you can make a adjustment of 2=B0 to bring it back to the desired rpm. Please let me know if you have any additional questions, kind regards Michael -- With regards, Michael Coates Company Director X-Air Australia Gold Coast, Australia. Tim ----- Original Message ----- From: hgmckay@bellsouth.net To: allegro-list@matronics.com Sent: Tuesday, October 30, 2007 8:34 PM Subject: Re: Allegro-List: Allegro 80 HP Woodcomp Pitch setting Tim: I agree, the 23.5 degrees is too much. I went through a series of emails on the rotaxengines-list@matronics.com back in October 2006 on this same subject. Go to that forum and look at the archived emails on the subject. I finally settled at 15 degrees which gave me 5100 rpm (static). If you ask Fantasy Air USA (Matt Smith) he will tell you they set all their props at 14 degrees. You will get various opinions on this subject, but 23.5 degres is certainly too much, and I believe every one will agree on that. At least I hope so!! Hugh McKay in NC Allegro 2000 Rotax 912 UL WoodComp Three Blade (Klassic 160/3/R N661WW -------------- Original message from "TIM MOSES" : -------------- What would be a good pitch setting for climb on an Allegro with the 80 HP Rotax and the Woodcomp prop? The previously reccomended pitch of 23.5 degrees at 7.875" from the tip seems like it is way too much. ________________________________ Message 2 _____________________________________ Time: 07:46:16 PM PST US From: hgmckay@bellsouth.net Subject: Re: Allegro-List: Allegro 80 HP Woodcomp Pitch setting Tim: Who am I to question the Australian Authorized WoodComp Service Center! It is interesting however to note that the Woodcomp Manual (at least the one I have) shows that the pitch angle should be measured 60 mm from the blade tip. For a 1600 mm diameter propeller (800 mm blade length from center of hub) this is 92.5% of the blade length. The little diagram shows that the blade pitch at this point can vary from 6 degrees to 17 degrees. All this is meaningless! Remember, the blade twist changes through out the length of the blade. I do not know why most prop manufacturers use the 75% length, and neither do I know why Mr. Coats uses 60% of the blade length (i.e 30% in from the blade tip). His procedure for setting the pitch is correct and I fully agree with it, but why 30% in from the tip vs. 25% in , I haven't a clue! Use either one, and then do your static test runs and adjust the pitch to get the max static rpm you desire without exceeding the Rotax limit. I do know this, you will have to choose what pitch you want for the engine performance you desire. Pitch angle is a trade off between high performance on climb out vs. most efficient cruise speed in horizontal flight. You will have to decide what you want, and set the pitch, do the static tests, and then fly the plane and find out if it performs the way you want it to. In the air check the cruise rpm at WOT. Hopefully you will be around 5500 rpm at WOT. If not come back, land and adjust the prop pitch accordingly (lower pitch angle = better climb out performance, higher pitch angle = better rpm cruise speed. I will note that I had a difficult time adjusting the pitch on my Allegro (I used the same method Mr. Coats described with the prop on the airplane). The blades would not rotate smoothly in the hub with the bolts loosened. They would slip and seize making it very difficult to get the bubble in the Warp drive protractor exactly in the middle. Hope you don't have the same dificulty. I would love to have a jig to do this on a level table rather than on the plane. Good Luck. Hugh McKay -------------- Original message from "TIM MOSES" : -------------- Hugh, I just got an email from the Australian Allegro/Woodcomp dealer and he said that the blade pitch is measured at "1/3 of the blade length from the tip". I thought it was customary to use the 75% blade span (ie. 1/4 of the blade length from the tip). So my question is what distance is this 14 or 15 degrees measured at? The following is the adjustment message I recieved from Michael Coats: setting up the propeller is no big deal but it must be done properly. forget the recommendations above, there is only one way to set the propeller and the instructions follow. Please note I am the Woodcomp certified service centre from Australia and New Zealand so I can tell you with certainty that the following information is correct. The correct distance the setting the blade measurement with just about every propeller ever manufactured is ***one third*** of the blade length in from the blade tip. You will see in the attached photographs I have made a very small T square which on the propeller I am using is 180 mm long, yours will be similar. In a pictures shown I am using a warp drive propeller protract which is probably the most common unit out there, is extremely cheap (approximate we $20) and will last a lifetime of normal use provided you don't drop it and break it. Step one, make sure the propeller blade is horizontal, if it is not horizontal get it is close to horizontal is you can and using a piece of wood or a broomstick or something like that marked the distance from the propeller leading edge to the ground and make sure that all of the other adjustments are made in this exact same position otherwise you will get varying blade angles. So firstly to set the propeller horizontal and then using the little T square position the propeller protract one third of the way up the propeller and take your adjustment. We mainly have cruise settings on our propeller and these follow below.... 80hp 18 degrees 100 hp 21 degrees If you want to get a bit more climb performance out of it I would suggest initially going approximately 1 1/2 degrees finer pitch, so for example on the 80 hp engine I would start at about 16.5 or thereabouts than it is a simple matter of adjusting each of the three blades on the propeller to get them all identical. Tighten up all the bolts and recheck after everything has been tightened just to make sure that nothing has moved. You can leave the propeller spinner off if you wish and go for a fly making sure that the performance and blade angles suit your needs. If you find your engine is over revving or you are using too many revs to your desired cruise speed simply course in the propeller up so go from 16.5 to approximately 17.5 and so on. On most of these propellers 1 of blade movement makes approximately 200 rpm difference as a general rule of thumb so if your aircraft is readying 400 rpm too high then you can make a adjustment of 2 to bring it back to the desired rpm. Please let me know if you have any additional questions, kind regards Michael -- With regards, Michael Coates Company Director X-Air Australia Gold Coast, Australia. Tim ----- Original Message ----- From: hgmckay@bellsouth.net Sent: Tuesday, October 30, 2007 8:34 PM Subject: Re: Allegro-List: Allegro 80 HP Woodcomp Pitch setting Tim: I agree, the 23.5 degrees is too much. I went through a series of emails on the rotaxengines-list@matronics.com back in October 2006 on this same subject. Go to that forum and look at the archived emails on the subject. I finally settled at 15 degrees which gave me 5100 rpm (static). If you ask Fantasy Air USA (Matt Smith) he will tell you they set all their props at 14 degrees. You will get various opinions on this subject, but 23.5 degres is certainly too much, and I believe every one will agree on that. At least I hope so!! Hugh McKay in NC Allegro 2000 Rotax 912 UL WoodComp Three Blade (Klassic 160/3/R N661WW -------------- Original message from "TIM MOSES" : -------------- What would be a good pitch setting for climb on an Allegro with the 80 HP Rotax and the Woodcomp prop? The previously reccomended pitch of 23.5 degrees at 7.875" from the tip seems like it is way too much. href="http://www.matronics.com/Navigator?Allegro-List">http://www.matronics.com/Navigator?Allegro-List href="http://forums.matronics.com">http://forums.matronics.com

Tim:

 

Who am I to question the Australian Authorized WoodComp Service Center! It is interesting however to note that the Woodcomp Manual (at least the one I have) shows that the pitch angle should be measured 60 mm from the blade tip. For a 1600 mm diameter propeller (800 mm blade length from center of hub) this is 92.5% of the blade length. The little diagram shows that the blade pitch at this point can vary from 6 degrees to 17 degrees. All this is meaningless! Remember, the blade twist changes through out the length of the blade. I do not know why most prop manufacturers use the 75% length, and neither do I know why Mr. Coats uses 60% of the blade length (i.e 30% in from the blade tip). His procedure for setting the pitch is correct and I fully agree with it, but why 30% in from the tip vs. 25% in , I haven't a clue! Use either one, and then do your static test runs and adjust the pitch to get the max static rpm you desire without exceeding the Rotax limit.

 

I do know this, you will have to choose what pitch you want for the engine performance you desire. Pitch angle is a trade off between high performance on climb out vs. most efficient cruise speed in horizontal flight. You will have to decide what you want, and set the pitch, do the static tests, and then fly the plane and find out if it performs the way you want it to. In the air check the cruise rpm at WOT. Hopefully you will be around 5500 rpm at WOT. If not come back, land and adjust the prop pitch accordingly (lower pitch angle = better climb out performance, higher pitch angle = better rpm cruise speed.

 

I will note that I had a difficult time adjusting the pitch on my Allegro (I used the same method Mr. Coats described with the prop on the airplane). The blades would not rotate smoothly in the hub with the bolts loosened. They would slip and seize making it very difficult to get the bubble in the Warp drive protractor exactly in the middle. Hope you don't have the same dificulty. I would love to have a jig to do this on a level table rather than on the plane. Good Luck.

 

Hugh McKay

-------------- Original message from "TIM MOSES" <tcmoses@earthlink.net>: --------------

Hugh,
I just got an email from the Australian Allegro/Woodcomp dealer and he said that the blade pitch is measured at "1/3 of the blade length from the tip".  I thought it was customary to use the 75% blade span (ie. 1/4 of the blade length from the tip).  So my question is what distance is this 14 or 15 degrees measured at?
 
The following is the adjustment message I recieved from Michael Coats:
 
setting up the propeller is no big deal but it must be done properly.
forget the recommendations above, there is only one way to set the
propeller and the instructions follow.  Please note I am the Woodcomp
certified service centre from Australia and New Zealand so I can tell
you with certainty that the following information is correct.

The correct distance the setting the blade measurement with just about
every propeller ever manufactured is ***one third*** of the blade length in
from the blade tip.  You will see in the attached photographs I have
made a very small T square which on the propeller I am using is 180 mm
long, yours will be similar.

In a pictures shown I am using a warp drive propeller protract which is
probably the most common unit out there, is extremely cheap (approximate
we $20) and will last a lifetime of normal use provided you don't drop
it and break it.

Step one, make sure th e prop eller blade is horizontal, if it is not
horizontal get it is close to horizontal is you can and using a piece of
wood or a broomstick or something like that marked the distance from the
propeller leading edge to the ground and make sure that all of the other
adjustments are made in this exact same position otherwise you will get
varying blade angles.  So firstly to set the propeller horizontal and
then using the little T square position the propeller protract one third
of the way up the propeller and take your adjustment.  We mainly have
cruise settings on our propeller and these follow below....

80hp 18 degrees

100 hp 21 degrees

  If you want to get a bit more climb performance out of it I would
suggest initially going approximately 1 1/2 degrees finer pitch, so for
example on the 80 hp engine I would start at about 16.5 or thereabouts
than it is a simple matter of adjusting each of the three bl ades o rtain
Tim
----- Original Message -----
Sent: Tuesday, October 30, 2007 8:34 PM
Subject: Re: Allegro-List: Allegro 80 HP Woodcomp Pitch setting

 

Tim:

I agree, the 23.5 degrees is too much. I went through a series of emails on the rotaxengines-list@matronics.com back in October 2006 on this same subject. Go to that forum and look at the archived emails on the subject. I finally settled at 15 degrees which gave me 5100 rpm (static). If you ask Fantasy Air USA (Matt Smith) he will tell you they set all their props at 14 degrees. You will get various opinions on this subject, but 23.5 degres is certainly too much, and I believe every one will agree on that. At least I hope so!!

 

Hugh McKay in NC

Allegro 2000

Rotax 912 UL

WoodComp Three Blade (Klassic 160/3/R

N661WW

-------------- Original message from "TIM MOSES" <tcmoses@earthlink.net>: --------------

What would be a good pitch setting for climb on an Allegro with the 80 HP Rotax and the Woodcomp prop?  The previously reccomended pitch of 23.5 degrees at 7.875" from the tip seems like it is way too much.






href="http://www.matronics.com/Navigator?Allegro-List">http://www.matronics.com/Navigator?Allegro-List
href="http://forums.matronics.com">http://forums.matronics.com
------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message allegro-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Allegro-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/allegro-list Browse Digests http://www.matronics.com/digest/allegro-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.