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  #21  
Old 05-03-2020, 08:03 PM
David Z David Z is offline
 
Join Date: Aug 2010
Location: Thunder Bay Ontario
Posts: 562
Default

Quote:
Originally Posted by DeeCee 57 View Post
Yet to fly an overpowered aircraft, patiently waiting...
Me too! There's certantly been times I wish I had more power. It's really easy to have less power by just closing the throttle to the desired amount.

Joking aside, just watch the airspeed and reduce power as needed if getting too close to the limit.
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Empennage Passed Pre-close Inspection
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  #22  
Old 05-04-2020, 06:14 AM
RV6_flyer's Avatar
RV6_flyer RV6_flyer is offline
 
Join Date: Jan 2005
Location: NC25
Posts: 3,630
Default

Quote:
Originally Posted by Earl Findlay View Post
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
It is ok and a little bit health to be afraid of an airplane. That helps keep you from doing things that you should not be doing.

What are you actually afraid of?
The engine will quit running?
The airplane falling apart?
The way the airplane flys? The quick sporty handling of RV aircraft can be scary to someone that has thousand of hours in SPAM cans.

The airplane does not know what kind of engine is pulling it through the air. The laws of physics will increase load on the airplane as it reaches higher speeds.

Typically aircraft require squaring the power to overcome the drag of the airframe to double the speed. Increasing horsepower from 160 to 180 is about a 13% increase in power. Yes that will make the airplane faster but typically one can retard the throttle (reduce manifold pressure) or decrease RPM to keep the HP at the same as a recommended 160 HP engine would produce at that altitude.

I once was asked to fly a 260 HP RV-8 solo on a several hour cross country flight. I flew the airplane local to get familiar with the handling of the HEAVY RV. It flew like a heavy RV but had a fantastic rate of acceleration and climb. It was a nice flying RV. It flew a lot like my 160 HP RV-6 when it was heavy BUT had a lot more acceleration and climb than my RV-6 did when light and solo. The trip was nice and enjoyable. I pulled power back in cruise to fly similar speeds and fuel burn that a typically RV-8 with 180 HP would see. When decening, one also keeps attention on airspeed so as to observe the law of physics and keep the aircraft flying in the middle of the performance envelope like it would with a smaller HP engine.

It is possible that you have an airplane that is not right for you. Being an EXPERIMENTAL airplane it can be changed to what you want. The TCDS lists the 360 as 10-pounds more weight than the 320 but 20 HP more. Lycoming does have some engines DERATED to lower HP. Typically this is done by limiting RPM and or manifold pressure. Evaluate all the different ways that the engine can be derated to not produce more than 160 HP at sea level. Yes lower compression pistons could be installed but if you are comfortable having the governor adjusted to limit RPM you can accomplish the same thing.

IF all this still scares you, only you can decide what comes next. Engine swap to the recommended 320 or sell / trade the aircraft for one that is less scary.
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Gary A. Sobek
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To most people, the sky is the limit.
To those who love aviation, the sky is home.
  #23  
Old 05-04-2020, 09:26 AM
Greg Dillon Greg Dillon is offline
 
Join Date: Mar 2005
Location: Upland,California
Posts: 83
Default Have no fear

'Scary' is an underpowered airplane in a high density altitude situation. My 9A with an EFII equipped 0-320 makes an estimated 175 hp. Gross weight takeoffs at lower altitudes at 100 deg oat are not a problem--easy 1000 fpm without 'pushing it' with high angles of attack. Departing out of a mountain airport with a D/A of close to 7000 ft at 110 kts resulted in an 800 fpm 'easy climb'. Enjoy the extra margin you get with more climb power, pull the throttle back and enjoy the reduced fuel burn while still doing an easy 150kts or better.
I've experienced gross weight 172s on hot days--'unpleasant' is a word I'd use to described those flights. 'Do-able' --yes. Within limits--yes...but not fun....RVs have limits just like any other aircraft---it's just the limits are farther out than you're used to flying lower powered certified planes.
  #24  
Old 05-04-2020, 09:54 AM
Ralph Inkster Ralph Inkster is offline
 
Join Date: Feb 2008
Location: Calgary, Alberta
Posts: 1,249
Default OP's response?

Earl, 22 responses later, do you have any thoughts on the posts to date? Do you have a better idea for an action plan to get the confidence you deserve when flying your aircraft?

Personally, I find the 9/9A a delightful plane to fly - with either engine - by knowing and respecting their limitations.
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built a few RVs, rebuilt a few more, hot rodded more, & maintained/updated a big bunch more
  #25  
Old 05-04-2020, 01:45 PM
ron sterba ron sterba is offline
 
Join Date: May 2007
Location: salem Oregon
Posts: 1,024
Default

Hi Earl, just wondering if you have the IO 360 D1A. It’s my understanding this is the 160 hp @ 2375 rpms. The later 172 Skyhawks used this engine of 360 ci for commonality by the manufacture but there was a limiting plate install to keep the aircraft at 160 hp. I too wanted to look at the D1A but a great deal at Sun-N-Fun from Vans on the IO 320 then added a wonderful CATTO prop!!! Flying 170 series Cessnas and Pipers for 45 years the 9A is delightful change. Just remember the farther the throttle goes in the faster the money goes out of your wallet for fuel! Like The pilots have said you’ll love it’s performance with 160 horse and I wholeheartedly agree. Beside the faster you go the less time you have to enjoy the scenery. And by the way you’ll love the rudder on the 9A too! I too enjoyed all the comments by the pilots and instructors for your post. Reading all of them was like going back to school but with excellent examples and feelings.Enjoy my friend Vans world of Flying!
  #26  
Old 05-04-2020, 02:13 PM
Aviaman's Avatar
Aviaman Aviaman is offline
 
Join Date: Feb 2018
Location: Louisville KY
Posts: 95
Default

The TAS redline (Vne) of the RV9A is 210mph not 170 mph. What are you worried about? I have an O-360 powered RV9A and have never exceeded 185mph WOT at any alitiude that I fly at (below 10,000). The extra power really helps in takeoff and climb performance. Just not an issue IMO. Of course TAS rises for a given IAS as altitude increases. My EFIS computes TAS, so that is what I am always seeing. I have never been close to Vne.
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John
Cessna 170B-sold
Zenith 601XL-sold
Vans RV-6 slider-sold
Vans RV-9A slider, flying
O-360, AFS EFIS, True-track autopilot, Garmin GDL-82 ADS-B, Garmin 327 Transponder, Garmin 496

Dues happily paid Jan 3, 2020
  #27  
Old 05-04-2020, 05:16 PM
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rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,256
Default

Quote:
Originally Posted by rvbuilder2002 View Post
The 160 hp recommended limit is related to more than just Vne, and as many times as I have posted about it in the RV-9 forum, I am amazed that it is still the first thing mentioned by some of the veteran RV-9 pilots.......

Here is one of the most recent threads discussing the details
http://www.vansairforce.com/communit...&highlight=vne

I agree that if the limiting speeds are obeyed, it doesn't matter what engine is in the airplane, but as I have mentioned repeatedly in the past, the scary thing is how many people flying with bigger than recommended engines obviously don't understand what all the limiting factors are. And that is why nothing bigger than a 160 HP engine is recommended.
Quote:
Originally Posted by Aviaman View Post
The TAS redline (Vne) of the RV9A is 210mph not 170 mph. What are you worried about? I have an O-360 powered RV9A and have never exceeded 185mph WOT at any alitiude that I fly at (below 10,000). The extra power really helps in takeoff and climb performance. Just not an issue IMO. Of course TAS rises for a given IAS as altitude increases. My EFIS computes TAS, so that is what I am always seeing. I have never been close to Vne.
Not to pick on you specifically John, but you perfectly prove my previous point.

Vne is not the only limit speed that RV-9(A) flyers need to keep in mind.
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Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.

Scott McDaniels
Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
  #28  
Old 05-04-2020, 06:23 PM
Larry DeCamp's Avatar
Larry DeCamp Larry DeCamp is offline
 
Join Date: Apr 2010
Location: Clinton, Indiana
Posts: 1,069
Default What is the REAL issue ?

1- You can?t hold Van accountable for CYA when 180HP can exceed his design criteria.
2-Does anyone know factually that a 10lb heavier engine with 180HP does not exceed some structural limit in the mount or airframe within published G limits , harmonic sympathies or maneuvering speed ?
3- If you assume responsibility for the unknowns above, you are the PIC. You control TAS

Just an observation from a gearhead with much less pilot cred than most people sharing there brain on this forum.
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RV-3B flying w/7:1 0320 / carb / Pmags / Catto 3b / digital steam
RV-4 fastback w/ Superior roller 360/AFP/G3X/CPI/Catto3b
Clinton, IN
  #29  
Old 05-04-2020, 07:28 PM
N941WR's Avatar
N941WR N941WR is offline
 
Join Date: Jan 2005
Location: SC
Posts: 12,887
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Quote:
Originally Posted by Larry DeCamp View Post
2-Does anyone know factually that a 10lb heavier engine with 180HP does not exceed some structural limit in the mount or airframe within published G limits , harmonic sympathies or maneuvering speed ?
...
Factually, I do know that at 1068 lbs empty, my O-360 powered -9 is lighter than my friend's O-320 powered -9A with a CS prop on the front.

As for Scott's concern about observing the yellow line, I simply don't cruise my plane at 75% because at those speeds it is DRINKING 100LL and with only 36 gallons on board, I would rather slow down to go faster, meaning I typically cruise around 150 to 155 knots burning around 7 GPH or less.

(If I slow to 130 knots my fuel consumption drops to around 5 GPH or less.)

The other thing about the -9(A) is, with its long wing, it is simply not comfortable hammering along in turbulence. When it is bumpy I slow down so they feel more like rollers than potholes and I hand fly it. I would do that even when I had only 135 hp up front.
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RV-9 (Yes, it's a dragon tail)
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Last edited by N941WR : 05-04-2020 at 07:36 PM.
  #30  
Old 05-04-2020, 07:37 PM
Aviaman's Avatar
Aviaman Aviaman is offline
 
Join Date: Feb 2018
Location: Louisville KY
Posts: 95
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@rvbuilder2002

?Not to pick on you specifically John, but you perfectly prove my previous point.
Vne is not the only limit speed that RV-9(A) flyers need to keep in mind.?

Did I say Vne is the ONLY limit speed that RV-9A flyers need to keep in mind? No, I didn?t. Of course there are other speeds. Many of them. I was confining my remark to a specific speed, Vne.
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Cessna 170B-sold
Zenith 601XL-sold
Vans RV-6 slider-sold
Vans RV-9A slider, flying
O-360, AFS EFIS, True-track autopilot, Garmin GDL-82 ADS-B, Garmin 327 Transponder, Garmin 496

Dues happily paid Jan 3, 2020
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