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  #21  
Old 02-09-2010, 06:33 PM
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N941WR N941WR is offline
 
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Quote:
Originally Posted by Finley Atherton View Post
Just had this random thought someone may be able to answer.
The RV-9 can float excessively in the flare if the speed is a bit high or if the idle is set too high. Would the bigger 180 HP engine with its bigger FP prop be likely to increase the length of the flare all other things being equal? The bigger engine/prop would produce more thrust at idle rpm, but possibly offsetting this the bigger prop would present a larger surface area to the airstream and therefore give a bigger engine/prop braking effect.

Fin
9A
Maybe but I doubt you will notice it. I'll let you know in a few months if your theory works or not.

Don't forget, that with the large engine, weight also goes up, thus increasing your stall speed. These two things may balance themselves out. I don't really know.
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  #22  
Old 02-09-2010, 07:00 PM
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db1yg db1yg is offline
 
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Interesting question Finley!

It seems to me that the pilot,, with some experience, automatically adjusts the nose up trim to compensate.

For example if the hypothetical 9a with a 320 and a fp Catto uses 65 kts indicated airspeed for their final approach then an equivalent 9a, but with a 360 and a Catto (pitched for the greater hp) might require a slightly higher angle of attack to maintain the same final approach speed which results in similar landing performance. The 9a airframe/wing likes a particular approach speed and the pilot cancels out the extra residual thrust from the bigger engine/prop with up trim to get to that magic number.

I have experienced relatively long landing distances on my 360/9a due to too high an idle setting and due to too high an approach speed. However, as Larry mentions, the 9 can also drop out from under you, similar to a 6 or a 7 (don't ask how I know) if you let the speed bleed off too much. With a constant speed prop the deceleration is quicker and therefore the potential drop out could occur even faster to a distracted pilot.

Cheers,

db
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  #23  
Old 02-25-2017, 05:49 PM
PilotjohnS PilotjohnS is offline
 
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Default Engine mount

Resurrecting an old thread, sorry about that.

I am planning on using a catto 2 blade on my RV 9. So this lends itself to using the weight savings for a bigger engine. I am curious if the RV9 O 360 has to use a custom engine mount, baffles and such. Or does Vans have Firewall Forward kit that is good for this combo?
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  #24  
Old 02-25-2017, 06:06 PM
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Greg Arehart Greg Arehart is offline
 
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Lots of 360s out there in RV9/9As. Uses same mount, baffles etc. as RV7 that you can order direct from Vans. Just let them know when you order the FWF kit what you want.

With the Catto, you may still be light on the nose. Difference between the Catto and aluminum Sensenich is about 30 pounds. But still within CG if you are careful how you set things up. Weight difference between 360 and 320 is only about 10 pounds (again depending on how they are set up).
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Last edited by Greg Arehart : 02-25-2017 at 06:09 PM.
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