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  #1  
Old 05-02-2020, 01:44 PM
Earl Findlay Earl Findlay is offline
 
Join Date: Jul 2019
Location: Sandpoint, Idaho
Posts: 85
Default I am afraid of my 360 powered RV 9A

I have spent extensive time online reading about overpowered 9As. My 9A is a 360 powered one, and I've realized that I am in over my head.

I am wondering, to be cautious should I make redline of my 9A Vc, which appears to be about 170 MPH. https://www.vansaircraft.com/wp-cont...2/hp_limts.pdf

Is it true that I am safe as long as I keep the true airspeed below 170 MPH?

Thank You.

Earl
  #2  
Old 05-02-2020, 01:52 PM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
Posts: 5,870
Default

being safe comes in many forms and levels. Not sure what you are afraid of or concerned with. VNE/futter, aircraft control, exceeding G limits from wind gusts, etc.

I routinely fly to the edge of Vno and often beyond that in non-turbulent conditions.

Larry
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N64LR - RV-6A / IO-320, Flying as of 8/2015
N11LR - RV-10, Flying as of 12/2019

Last edited by lr172 : 05-02-2020 at 01:57 PM.
  #3  
Old 05-02-2020, 02:20 PM
CanyonDweller CanyonDweller is offline
 
Join Date: Jan 2013
Location: Floydada, TX
Posts: 42
Default

http://www.vansairforce.com/communit...d.php?t=181789
Read what Airguy did last weekend in his 9A, and be sure to read his sig line at the bottom of his post.
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  #4  
Old 05-02-2020, 02:25 PM
RV8JD RV8JD is offline
 
Join Date: Jan 2005
Posts: 303
Default

Since you referenced the Van's article on HP limits, Vne, and TAS, I assume you are concerned about Vne as a function of altitude.

Vne (Redline) for the RV-9/9A is 210 MPH TAS/182.5 KTAS (although you wouldn't know it from official Van's literature). The table on the left in the chart below shows Vne in terms of IAS at different altitudes for a Vne of 210 MPH TAS/182.5 KTAS.



Vno (Maximum Structural Cruising Speed) is 180 MPH IAS for the RV-9/9A. Note that at 10,000 ft, Vno is about equal to Vne. Above 10,000 ft, Vne is lower than Vno and governs.

Hope that helps,
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RV-8
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Last edited by RV8JD : 05-02-2020 at 02:34 PM.
  #5  
Old 05-02-2020, 02:32 PM
bjdecker's Avatar
bjdecker bjdecker is offline
 
Join Date: Jun 2005
Location: Georgetown, TX
Posts: 533
Default Don't be afraid...

...do more flying...

Per the manual, the Vne for the RV-9 is 210mph. Vno is 180. Va is 118mph

Consider the extra 20hp (assuming that you have an O-360 or IO-360-B variant of 180H.P.) a gift that yields shorter take off rolls, faster rate of climb, higher cruise, more performance margin...
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Retired Firmware Guy and Airplane Builder

2020 RV-14 QB -- Under construction - Tailcone & Empennage Complete.
2018 RV-7 QB -- Built, Flying
2007 RV-7 QB -- Built, Drowned, Resurrected and flying
1998 RV-8 QB -- Started, Sold
1986 Mooney 205SE
1980 Mooney 231

Aided and abetted building a number of other RV's.
  #6  
Old 05-02-2020, 02:48 PM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
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Quote:
Originally Posted by Earl Findlay View Post

Is it true that I am safe as long as I keep the true airspeed below 170 MPH?

Thank You.

Earl
No. Va is well below that. You need to better understand the conditions you encounter and how they relate to airframe safety. A full elevator pull at 170 will likely create serious damage.

Larry
__________________
N64LR - RV-6A / IO-320, Flying as of 8/2015
N11LR - RV-10, Flying as of 12/2019

Last edited by lr172 : 05-02-2020 at 02:53 PM.
  #7  
Old 05-02-2020, 07:33 PM
rockwoodrv9 rockwoodrv9 is offline
 
Join Date: Dec 2011
Location: Meridian ID, Aspen CO, Okemos MI
Posts: 2,715
Default

Earl,
I have a car that will do about 170mph. I dont drive it that fast. When I am on rough roads, I drive it much slower.
Considering you are north of me (KEUL), the extra hp will be nice in the mountains. I really wanted a 360 but got too good of a deal on a 320. Let me know if you want to trade!
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Williamston MI
O-320 D2A
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  #8  
Old 05-02-2020, 08:43 PM
terrye terrye is offline
 
Join Date: Feb 2010
Location: Vancouver, BC, Canada
Posts: 929
Default I am afraid of my 360 powered RV 9A

The RV-9A standard engine of 160 hp is the same engine as used in Cessna 172s and Piper Cherokees, both 4 place planes. Based on that, the RV-9A is "overpowered", meaning it has a higher power to weight ratio, and this is responsible for its remarkable performance. A 180 hp (I)O-360 is only 12.5% more powerful, so you might even find the standard 160 hp engine "over your head" too. The solution is likely more training with a qualified instructor. And remember, the throttle works in both directions.
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RV-9A (Fuselage)
2020/2021 VAF Contribution Sent
  #9  
Old 05-03-2020, 07:23 AM
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airguy airguy is offline
 
Join Date: Oct 2006
Location: Garden City, Tx
Posts: 5,358
Default

Yesterday afternoon I departed KSJT at 103F on the ground, don't even want to guess what the runway surface temperature was. Density altitude was 5800. Two butts in the seats and 28 gallons plus about 40 pounds in the baggage compartment. I came off the runway on an intersection departure and pitched for about 95 knots in the climb, about a minute and a half later Tower calls me and asks "What engine do you have in that thing?"

I was climbing at 1600/min in that heat with that load - and I wasn't really pushing it.

THAT'S why we (some of us, anyway) put 360's on the 9. It's not for flat-out speed, because it doesn't buy you any more Vne or Vno or Va - those are structural limits and you ignore them at your own peril. It's for the ability to get out of Indian Country and get up high quickly and let that wing do it's thing in mid teens where it wants to be.

Think of it this way - if you are worried about the extra horsepower, don't use it. Simply limit your maximum manifold pressure by 2" less than whatever airport you are taking off from, and you'll be equivalent to the 320. Just because you HAVE the extra horsepower doesn't mean you must use it. Just like a new car driver with a hopped-up mustang, ease into it gradually and feel it out, rather than going drifting around the street corners. The extra power is really nice when you want it - but it's optional, and you have the control literally in your hand.
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Greg Niehues - SEL, IFR, Repairman Cert.
Garden City, TX VAF 2021 dues paid
N16GN flying 750 hrs and counting; IO360, SDS, WWRV200, Dynon HDX, IFD440
Built an off-plan RV9A with too much fuel and too much HP. Should drop dead any minute now.
  #10  
Old 05-03-2020, 07:29 AM
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FORANE FORANE is offline
 
Join Date: Nov 2011
Location: East TN
Posts: 582
Default

Quote:
Originally Posted by airguy View Post
Just because you HAVE the extra horsepower doesn't mean you must use it.
I'm not sure this is accurate information.
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