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sensenich prop pitch


larry.spicer@...
 

Looking for pitch setting for older sensenich 64” ground adjustable . going on a 3300 sonerai. Any help or suggestions welcome.



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David Amsler
 

Make sure that older prop meets Jabiru's very limited maximum inertia requirements,  With flywheel on wrong end of engine, bad things can happen with too much mass in the prop.  Some newer props are lighter.

David A.

On Tue, Mar 16, 2021 at 12:36 PM <larry.spicer@...> wrote:

Looking for pitch setting for older sensenich 64” ground adjustable . going on a 3300 sonerai. Any help or suggestions welcome.



This message and its attachments may contain legally privileged or confidential information. It is intended solely for the named addressee(s). If you are not an addressee indicated in this message (or responsible for delivery of the message to an addressee), you may not copy or deliver this message or its attachments to anyone. Rather, you should permanently delete this message and its attachments and kindly notify the sender by reply e-mail. Any content of this message and its attachments that does not relate to the official business of Fox Corporation, or its subsidiaries must be taken not to have been sent or endorsed by any of them. No representation is made that this email or its attachments are without defect.


Jay Scheevel
 

I have uploaded to the files section a procedure for measuring rotational moment of inertia. I stole it from a Rotax forum a few years back. It works for any prop you may be thinking of installing. Moment limits are listed in the Jab installation manual.
Jay


larry.spicer@...
 

this prop is for the 3300, 1 year old just not the newest one out 1 year ago, again i need angle and where measured


Jim Chuk
 

I've adjusted quite a few props over the years, and in fact was adjusting one today.  Will finish that one tomorrow.  If you know what static rpm you want to see, basically pick a pitch, set both blades to that same pitch, and see what it will turn up to at full throttle.  If you don't have enough pitch, be careful you don't over rev the engine though.  If you have to low of a static rpm, take out some pitch and test it at full throttle, if you have to much static rpm, add some pitch to the prop.  I've heard it said that 2850 was a good static rpm for the Jabiru, I'm more like 2900 or a bit more.  On climb out, I hit about 3100.  It seems every prop manufacturer's numbers are different, so it mostly comes down to what your static rpm is.  I was setting up my brand new NR prop on the kitfox with a 912 today.  JImChuk


On Tue, Mar 16, 2021 at 3:41 PM <larry.spicer@...> wrote:
this prop is for the 3300, 1 year old just not the newest one out 1 year ago, again i need angle and where measured


glen english LIST
 

Jim. good advice-

In the Jabiru 3300 the torque curve is flat ish.
But the 2200 has a bump at 2500 and about 10% down on that at 3100
(graphs in engine manuals) Fig8. Fig 9 of JEM0002-9

For me, these rather different torque curves, this would imply that the 3300 should be WOT static pitched different for a 2200 engine.
any comment ?

On 3/17/2021 2:18 PM, Jim Chuk wrote:
I've adjusted quite a few props over the years, and in fact was adjusting one today.  Will finish that one tomorrow.  If you know what static rpm you want to see, basically pick a pitch, set both blades to that same pitch, and see what it will turn up to at full throttle.  If you don't have enough pitch, be careful you don't over rev the engine though.  If you have to low of a static rpm, take out some pitch and test it at full throttle, if you have to much static rpm, add some pitch to the prop.  I've heard it said that 2850 was a good static rpm for the Jabiru, I'm more like 2900 or a bit more.  On climb out, I hit about 3100.  It seems every prop manufacturer's numbers are different, so it mostly comes down to what your static rpm is.  I was setting up my brand new NR prop on the kitfox with a 912 today.  JImChuk
On Tue, Mar 16, 2021 at 3:41 PM <larry.spicer@fox.com <mailto:larry.spicer@fox.com>> wrote: