[Tom Finch]

Ok, this is my first post and I have a question. I have been lurking on the site for a couple of weeks and reading everything that I could. What I want to know is this; what is the real life difference between the 7A and the 9A? I am considering the 7A but wonder why the 9A seems more popular when it is slower with less aerobatic and payload capability and the only physical difference is the wing. I want to make a decision at Oshkosh and go from there. I am only asking what are the differences are not implying that one is better than the other.

Thanks,
Tom Finch

 

[Radomir]

7's outsell 9's with a 2:1 margin (tail kits)... so not sure where this impression came from...

but wonder why the 9A seems more popular

 

[Lionclaw]

I went with the 9A because I wanted the option of using a smaller powerplant (235 or 290), but ended up going with a 320 anyway. Vans lists a slower stall speed for the 9A over the 7A. I'd imagine (just guessing) that the 9 would also have a better glide ratio. So it is perhaps a better trainer. I don't even have my PPL yet (almost done), so it seemed the right choice for me.

Eventually I may want to do acro. When that time comes I'll look into building an 8, so long as I can convince the wifey that the back seat is the cool place to be. Otherwise it will perhaps be the 7...

Anyway, that's just my reasoning.

 

[N941WR]

I am considering the 7A but wonder why the 9A seems more popular when it is slower with less aerobatic and payload capability and the only physical difference is the wing.

Tom,

Welcome to the VAF!

The -9 isn't really that much slower, 192 vs. 189 when both are powered by O-320's.

As for the payload, the -9's tend to be a little lighter (or should be) due to the smaller engine, thus use useful load should be very close. My -9 has a 760 lb useful load, which is more than I can even think about stuffing in it, and that is with the GW set at the Van's recommended 1750 lbs.

Do a search on the choice topic, it has come up a few times. The selection of the -7 vs. -9 really comes down to personal choice. A lot of people are looking for a good cruiser and don't care about doing acro, thus they buy the -9. Other's want speed and acro above all else.

Just remember, build what you want, not what others want you to build.

 

[alpinelakespilot2000]

Definitely do a search in the archives. Type "RV-7a RV-9a" or "RV-7 RV-9" in a "titles only" search with the advanced search option and that should be more than enough information to keep you busy.

There are some significant things each will do that the other cannot. You have to decide which ones matter to you. Good luck with your decision.

 

[terrykohler]

Tom:
Comprehensive testing of several Van's models is available on www.cafefoundation.org. You will see that the 9 has a substantially slower roll rate than the other RVs. This translates into better stability as a cruiser and as an instrument platform. Also, as stated previously, good glide (12:1)and lower stall. Tradeoff is lack of acro capability and limitation (not always followed) of H.P. at 160.
Terry

 

[videobobk]

To me, whether or not you want to do acro is the only real consideration. I have flown both and am happy with my choice of 9A. It does seem to make up for any speed differences higher up and I really like the low approach/stall speed. If it were ever to become a glider, I would be very happy to be in the 9A. That being said, if I had wanted acro, I would have chosen the 7.

Welcome to VAF. It's gonna cost you!

Bob Kelly

 

[Mel]

Wing is not the only difference.

.......and the only physical difference is the wing.

The wing is not the only physical difference. The horizontal tail feathers on the -9 are quite large.
As stated before, if you want to do acro, go with the -7. If not, go with the -9. Speeds are VERY close and the low speed characteristics are much nicer with the -9. The short wing RVs start to drop pretty fast at speeds below 80 mph. Not so with the -9.
You can't miss with either.

 

[Tom Finch]

Thanks for the input

It sounds like the big difference is acro or no acro. At this point, I am mostly looking for a cross country cruiser for my son and I and not an acro machine. I am mostly interested in speed and useful load. I would prefer the extra hp of the O360 in a 7 but like the slower approach of the 9A. I guess I should try to get a ride in each and think about it from there. I thought I saw a 9 with a 360 but I am sure that you can build a 320 that will get more hp than 160 too. Decisions, decisions, decisions, decisions..................

 

[Mel]

Maximum recommended hp for the -9 is 160.

And that's all you need! Anywhere!
You will get conflicting opinions but, I have flown an RV-6 with a tired (2500+hrs) 150 hp engine out of Leadville, CO. in the summer with no problems.

 

[L.Adamson]

And that's all you need! Anywhere!
You will get conflicting opinions but, I have flown an RV-6 with a tired (2500+hrs) 150 hp engine out of Leadville, CO. in the summer with no problems.

I agree. We're up here in the mountain country of Utah, Idaho, and Wyoming flying a 160hp RV-9A with two people at 225lbs+ each. It does very well performance wise, and especially with it's Hartzell C/S prop.

L.Adamson --- RV6A

 

[Tom Finch]

thanks

Mel,
Thanks for the advice, I did read an article on the Vans site why you can't put a bigger engine in the 9A and it basically stated that it will easily exceed the Vne for the wing and bad things happen after that. I will then have to go back and then compare useful loads and take some rides in them but it sounds like I may be a 9A builder than a 7.

Tom

 

[N941WR]

Tom,

A good number of people will tell you to put the O-360 in your -9, but with a GW takeoff roll of 475' and a GW climb of 1,400 FPM you have doubled the performance of a 172. How much climb performance do you really need?

Keep it light and you will be much better off than if you put in the larger engine.

 

[cnpeters]

I spent months hashing the same decision. Despite some nuances between them, it basically comes down to whether you want to do even occasional acro or not. I didn't, and wanted mainly a stable cross country machine - the -9A won out. Regarding engine size - don't worry - speed differences are trivial (a couple percent). I have decided to put in an IO-360 in my -9A with a fixed pitch prop (will save big bucks over a constant speed, no overhauls). I will have it pitched for cruise (I haven't seen numbers to prove a constant speed can beat Craig Catto's prop pitched for cruise), thus my takeoff performance will be lower than a c/s prop - BUT, the performance STILL will smoke most of the commercial GA planes. That is where I like the idea of the 360 with a little more hp - it will improve my climb performance a little with the fixed pitch prop. In cruise, I still can't hit near Vne, but will need to be careful descending. However, it would be easy also to nose over a -9A with an O-320 and exceed Vne - care is required either way, just a bit more with the 360. In terms of weight, there is only about 10 lbs between the 320 and 360. Look at Van's published numbers to see how much weight is required before performance numbers really change - 10 lbs is nothing, plus offset with the lighter fixed pitch prop compared to the heavier c/s.
Another point is performance - in 2 years collecting folk's performance data from their flights, I am seeing a little improvement in fuel burn per given speed in a leaned out fuel injected 360 over the 320. Not much, but seems to be real. Since fuel prices are going TU, my mission is to extract the most speed per gallon of fuel - thus definitely fuel injection running lean of peak (can give you about 1 gal per hour over a carb at the usual ROP, though there have been some flyers like Pete Howell that have done some LOP carb work with carb heat on). Another data point for my choice so far with the 360 at 180hp is to use lower compression cylinders and have the ability if I want to use mogas and save money. Though a 320 at 150 hp can too, but performance drops (if I recall correctly, the O-320 at 160hp has higher compression precluding the mogas option).
It all depends on your requirements and mission. You really for now just need to decide on the aerobatic part - the engine choice is far down the road deep in your build. Sorry for the rambling, and welcome to the forums!

 

[Finley Atherton]

I have decided to put in an IO-360 in my -9A with a fixed pitch prop.
Since fuel prices are going TU, my mission is to extract the most speed per gallon of fuel

I agree with your reasoning for the 9. I would add that there is nothing like being able to fly slow and stable (just as much fun as acro )
If you really want the most speed per gallon of fuel then you should consider the C/S prop over the FP. At 65% power and 2000 rpm an IO-320 will use 13% less fuel than the same engine at 65% power and 2700 rpm. Problem is that if you decide on a C/S prop then you may have to change from the IO-360 to the IO-320 to stop the nose of the 9 getting too heavy! Life is full of compromises.

Fin
9A Flying

 

[Tom Finch]

320 or 360

I have a better understanding of the airframe but what about those that feel that the -9A will benefit from an O360 vs an O320? Is it just that slowing down in a larger engine yields better MPG or is it performance based? I realize that they are experimental but what about exceeding Vne and flying the wings off? and then there is the CG envelope, that has to be a factor. I have seen that there are O360 -9A's flying but how is that going? It sounds good but it sounds like there is a downside as well. Can someone offer some insight into this part of the -9A as well?

Thanks,
Tom

 

[airguy]

The CG is a non-issue - simply move some optional-location weight to the rear. The battery is the easiest way to do that; some avionics will allow you to put the processor in a remote location as well, the ELT can go back in the tail cone with a remote activation switch. That is a once-and-done problem solving exercise during the building of the aircraft.

As for exceeding Vne - it can be done in a 9A powered with a 290 also. Heck, it can be done in a glider powered by nothing but gravity. It's pilot technique, pure and simple. The airplane is not in charge - you are. Be a pilot, not a passenger, and control the airspeed through judicious application of power. The advantage of excess power is quick climb rate, higher service ceilings for mountain flying or weather avoidance, and good performance when high, hot, and heavy. The IO360 option on a 9A is not like a JATO bottle - it comes with a throttle that should be used when appropriate.

 

[alpinelakespilot2000]

The advantage of excess power is quick climb rate, higher service ceilings for mountain flying or weather avoidance, and good performance when high, hot, and heavy.

I agree with this, but I would also argue that any 2-seat RV with an O-320 (or, as Bill R. shows with the 0-290 in his -9) will already provide this. Just look at Van's advertised performance numbers for confirmation. If you need more power in an RV, then you really should not have been where you put yourself in the first place. The "more power is always better" mentality is, IMHO, relatively meaningless when applied to RVs.

 

[N941WR]

... and then there is the CG envelope, that has to be a factor. I have seen that there are O360 -9A's flying but how is that going? It sounds good but it sounds like there is a downside as well. Can someone offer some insight into this part of the -9A as well?

Thanks,
Tom

Tom,

Check out Dan C's W&B page to get an idea of how other plane's W&B have come out. The page lists engine type, prop, and whatever else the owner wanted to include.

 

[Tom Finch]

great tool

Bill,
Thanks for the link to the W&B site, it is a great tool. I appreicate all of the responses that everyone has taken the time to write. I look forward to seeing and talking to Vans at Osh next month. I will have plenty of time to make the engine decision but I am glad to get all of the advice and opinions that people are willing to share.

Tom

 

[airguy]

I agree with this, but I would also argue that any 2-seat RV with an O-320 (or, as Bill R. shows with the 0-290 in his -9) will already provide this. Just look at Van's advertised performance numbers for confirmation. If you need more power in an RV, then you really should not have been where you put yourself in the first place. The "more power is always better" mentality is, IMHO, relatively meaningless when applied to RVs.

Granted, the entire RV series are pretty nice hotrods straight out of the box. Having said that, it is human nature to tweak and tune to get the most out of our toys. If I can plaster a big 'ol honking grin on my face by adding 10 pounds of motor, and still manage to fly it safely by paying attention to what I'm doing, what's wrong with that?

Is it needed? Nope.
Is it fun, neat to have, and occasionally handy to use? You bet.

Corvettes don't need red paint, and bass boats don't need 225 horse outboard engines either - but you still see them all over the place. It's not because we NEED to - it's because we CAN.

 

[alpinelakespilot2000]

Granted, the entire RV series are pretty nice hotrods straight out of the box. Having said that, it is human nature to tweak and tune to get the most out of our toys. If I can plaster a big 'ol honking grin on my face by adding 10 pounds of motor, and still manage to fly it safely by paying attention to what I'm doing, what's wrong with that?

Is it needed? Nope.
Is it fun, neat to have, and occasionally handy to use? You bet.

Corvettes don't need red paint, and bass boats don't need 225 horse outboard engines either - but you still see them all over the place. It's not because we NEED to - it's because we CAN.

I agree with you, Greg. If you WANT more power, by all means go for it. Your post just got me thinking about a larger issue.

I was reallly referring more to those who argue that you somehow NEED more power. And that somehow having more power is going to somehow make for a "safer" plane. This is especially true for the RV-9 where--despite Van's having argued adamantly, and going to the trouble of writing an indepth article on why more power is not better--many try to justify putting in an 0-360 into an RV-9 using a "safety" or "you-can-never-have-too-much-h.p." argument.

 

[rtry9a]

I agree with you, Greg. If you WANT more power, by all means go for it. Your post just got me thinking about a larger issue.

I was reallly referring more to those who argue that you somehow NEED more power. -many try to justify putting in an 0-360 into an RV-9 using a "safety" or "you-can-never-have-too-much-h.p." argument.

I wonder if you would have the same opinion if you lived at 5000+ feet and surrounded by 10-13,000 ft peaks? We generally start out with ~ 70% of rated engine power (from the thinner O2 content) and then have to consider density altitude, weight, and wind to get into the wild blue?

 

[kentb]

Yes

I wonder if you would have the same opinion if you lived at 5000+ feet and surrounded by 10-13,000 ft peaks? We generally start out with ~ 70% of rated engine power (from the thinner O2 content) and then have to consider density altitude, weight, and wind to get into the wild blue?

I have flown my Cessna 172 in eastern Oregon and was very concerned about making sure that I didn't go beyond the POH limits.

With my RV9A (160hp) I do the same thing, it is just the POH lets me easily work under those condition without much restriction.

Hot and heavy my C172 at 5000 could only make a couple hundred ft per min.
The RV at that atl could easily make over 1000 ft / min.

Kent

 

[smokyray]

More Power Scottie?

http://www.youtube.com/watch?v=eoJEX3hdXqw

Smokey
HR2

 

[airguy]

I agree with you, Greg. If you WANT more power, by all means go for it. Your post just got me thinking about a larger issue.

I was reallly referring more to those who argue that you somehow NEED more power. And that somehow having more power is going to somehow make for a "safer" plane. This is especially true for the RV-9 where--despite Van's having argued adamantly, and going to the trouble of writing an indepth article on why more power is not better--many try to justify putting in an 0-360 into an RV-9 using a "safety" or "you-can-never-have-too-much-h.p." argument.

Needed? No, not even for a safety argument. A 9A with a 320 will have plenty of power to launch even at gross weight from Leadville. It's more the Gee Whiz factor than anything else.

We can make all kinds of excuses as to why we THINK we need more power, but it all boils down to "Mines bigger than yours". 320/360 really is the practical limit for the 9A airframe, and it takes you to the point where pilot skill must be higher and exercised more often to keep you out of the "dragon zone" of the flight envelope, and is certainly not for everyone. Having said that, for pilots/builders who are fully cognizant of the dangers and higher requirements of going there, it can be a fun place to live!

I'll be the first to admit that I want a 360 and C/S prop on mine so that I can cruise in the high teens and turn high TAS. I want to be able to blast off the runway in 400 feet and climb at 2500 at solo weight. I want to be able to play leapfrog with Mooneys. And while doing all that, I'll bet my 360 spends about 10% of it's entire life producing more than 80% power - but it's that 10% that I'm willing to pay for.

I'm already in trouble with my wife because I told her that my NEXT plane will be a HR2...

 

[L.Adamson]

I wonder if you would have the same opinion if you lived at 5000+ feet and surrounded by 10-13,000 ft peaks? We generally start out with ~ 70% of rated engine power (from the thinner O2 content) and then have to consider density altitude, weight, and wind to get into the wild blue?

Actually, the 0320 powered RV9A fly's out of Bountiful Skypark (KBTF) just fine! I should know, as I did two cross country flights in it last week. Even the other 150 hp version could make it up the canyon and duck under Class B airspace.
Just make sure it has the C/S prop. I wouldn't want one without it!

L.Adamson

 

[alpinelakespilot2000]

I wonder if you would have the same opinion if you lived at 5000+ feet and surrounded by 10-13,000 ft peaks? We generally start out with ~ 70% of rated engine power (from the thinner O2 content) and then have to consider density altitude, weight, and wind to get into the wild blue?

Actually, I fly surrounded by peaks that are 10K-14K feet and fly into the mountains where field elevations are at or above 5000ft. I would still argue that any 9 will fly just fine in most of these conditions and I decided to build a -9 with an 0-320 with this type of flying in mind. Just need to use common sense. In the morning and evening when one "should" be flying in the mountains, even the 182 I have most of my hours in will do just fine, even with its measly (relative to weight) 230hp and 1100fpm climb.

I would also argue that there are greater dangers having too much h.p. in the -9. If I remember correctly from Van's admonishments, and as counterintuitive as it seems, it is not IAS that matters as much as TAS. While your airspeed indicator may not indicate over redline, TAS could be adifferent story entirely. Vans warnings should be of special concern precisely to those who do fly in a mountainous environment (like Colorado, especially) where afternoon or wave turbulence are notorious and can do very consequential damage to an airplane very quickly. For more on this, see Van's article: http://www.vansaircraft.com/pdf/hp_limts.pdf

Again, I don't begrudge anyone putting an I/0-360 in a -9. I just think that arguing for it on the basis of safety, despite Van's explicit warnings and despite the fact that RVs have excess performance already, doesn't make much sense in real life.

 

[Bryan Wood]

I'm on both sides of this

Mel,
Thanks for the advice, I did read an article on the Vans site why you can't put a bigger engine in the 9A and it basically stated that it will easily exceed the Vne for the wing and bad things happen after that. I will then have to go back and then compare useful loads and take some rides in them but it sounds like I may be a 9A builder than a 7.

Tom

While the article that you read about "All The Pretty Horses" will scare the snot out of you the story isn't all there. It implies that you can go 180 mph indicated in a 9. Okay, at 1000 feet with everything in maybe you can get into the yellow, but not in normal cruise altitudes. In order to get to the answer that you are seeking you will have to read between the lines. Here are a couple of thoughts for you to consider. Using the CAFE's test of the RV-9A you can see that at the INDICATED airspeed at 8,500' never goes over 170mph. This is with the throttle all the way in and 2600rpm. Look on page 12 of the report if you would like to check it for yourself. If you were to look at the airspeed indicator for the 9/9A you will see that the yellow arc starts at 180mph indicated. This gives 10mph of cushion just to get to the cushion. This has always screamed that my engine is to small to me. Your conclusions may vary. There is also the flutter issue for excessively high true airspeeds, but you can control this with your throttle on decents from high altitudes.

Now for the flip side of this. When arguing the need for more than 160hp on the 9's for higher elevations you just can't imagine how much the wing takes over on the 9's at altitude. It is something you have to experience to believe and here is an example for you. Taking off as a 2 ship from a 9,000' density altitude airport with an 0-360 180hp short winged RV with a constant speed prop in front of me, our 9A was in the air sooner than the other plane. I had to fly off to the side of the runway while the short winged plane built up speed. This takeoff simply amazed me! But, once in the air the other plane pulled us slightly, but very little. In other words the wing and the constant speed prop on my 0-320 allowed us to take off in roughly half of the takeoff roll of the other plane. (I have video of this because we often rest the camera on the glareshild when we fly with others) As Van originally said he wanted this design to fly on it's wings, not on a big engine. Simply put, it does. Given the choice of an 0-320 with a constant speed prop, or an 0-360 with a fixed pitch this would be a no brainer for me. It would be 320/CS one hundred times out of a hundred. But a 0-360 with say a Whirlwind CS, well somebody hose me down please. That sounds really, really good!

So what does this mean? Anybody who thinks a 9 is underpowered with an 0-320 is wrong in my opinion. The thing goes like crazy and and does everything well. But, is there room for a little more speed? Go check the CAFE report and see that I'm not pulling your leg on that.

Good luck in your decision.

 

[rtry9a]

Actually, the 0320 powered RV9A fly's out of Bountiful Skypark (KBTF) just fine! I should know, as I did two cross country flights in it last week. Even the other 150 hp version could make it up the canyon and duck under Class B airspace.
Just make sure it has the C/S prop. I wouldn't want one without it!

L.Adamson

Larry, I thought Bill mentioned that his 320 clone produced more than the OEM Lyc specs, close to the 360's output- 170 HP I believe he said. I assume you are helping him fly off his 40hrs in the new 9A, correct?

I understand Van's comments about watching speeds up high, but extra HP does hot hurt if it does not weigh too much or mess up the cg's. I agree with you both about the C/S prop.

 

[db1yg]

Hi Tom,

This "360 in an RV9(a)" issue generates almost as much discussion as the tip up vs slider, tail wheel vs nose wheel, 7 vs 9, etc.

Just as another data point I offer the following which is the thought process I went through several years ago when I was considering the RV model and engine combo for my build. It was written in response to a question posted by Aussie 9a.

Aussie 9a,

You asked for input from anyone who has "experience fitting 180 hp to an RV-9(a)". I did just that and have been happily flying that airplane since March of last year. Many of the reasons for the selection of that engine parrallel those of Questair. The following is a summary of the features that we wanted in an aircraft along with the factors that lead to my engine/prop selection;

I wanted a two place airplane that was a stable IFR capable cross country flyer (no interest in aerobatics) so I selected the 9a. I wanted simple operation as my wife intends to finish up her private pilot training in the plane. However, it needed to have excellent take off performance as we will be living in N. Az. where afternoon summertime density altitudes are frequently challenging. I also wanted to keep costs down (who doesn't), wt down, and select an engine/prop combo which provided smooth/quiet operation on long x-c flights.

I boiled my options down to a 9a with an 0320 and a Hartzell cs (Vans recommendation) or a 9a with an 0360 and a Catto 3 blade composite fp.

Cost: The difference in cost of a new experimental 0320 vs 0360 at Vans or Americas Aircraft Engines (ECi) is $500--I suspect Mattituck and Superior are similar differentials.
The cost of a new Hartzell plus governor is around $7K (at the time I was shopping) while a Catto 3 bade with the Sabre spacer is $2K. The cost of the 360/Catto is therefore $4500 less than the 0320/Hartzell.

Weight: The weight difference between the 0320 and the 0360 per Lycomings certificated weight tables averages less than 10 lbs. The difference in wt between the specific 0320 model Vans sells(D1A) and the specific model 0360 they sell (A1A) is less than 6 lbs.
The Hartzell CS with governor totals around 60 lbs. while the Catto plus spacer weighs in at 20 lbs. Using the 10 lbs engine wt differential, the weight of the 360/Catto is therefore around 35 lbs lighter than the 320/Hartzell.

Performance: Although I have never tested this, I suspect that the 0320 with the CS prop will climb better than my fp 0360 but my guess is that the difference is small.
The cruise performance of the 0360/Catto is better than the 0320/Hartzell if you want to use 75% power numbers---if you cruise the 0360 at 65-67% you will see close to the same performance in cruise/ff as the 0320 running at 75% while creating less noise and putting less stress on the engine.

I fly this plane at 66-67% power (seems to have a sweet spot there) per the Lyc chart and see performance #s that exceed Vans published 75% 0320/CS numbers (probably due to the James cowl/plenum). Additionally at these relatively low power settings the engine/3 blade composite prop combo is extremely smooth and with the slower prop tip speeds it is also relatively quiet.

Downside: If you elect to fly at 75% power you will not be able to hit Vne in level flight at altitude (with a stock 180 hp) but you will be closer than a 320 9a and must therefore be careful when transitioning from cruise to descent--although any RV will quickly pick up speed in descent if the power is not managed correctly.

Given the options would I do it again? Lets see: over $4000 less cost, 35 lbs less wt, better cruise capability, similar climb capability, less engine stress, lower noise, less complexity/maintenance, and smooth operation-----yea, faced with the same two options I would most likely do it again!!
__________________

The above was written some time ago so the prices have surely changed.

I should also mention that I can confirm comments by other 9 drivers relative to high altitude flight. This 9 wing really likes to be between 9 and 14k ft for cruise. It simply does not give up speed even thought the power (and FF) is dropping off until I get above 13k density.

Whatever you choose to do, either a 7 or 9, 320 or 360, tail wheel or nose wheel, the RV will give you years of practical/low cost transportation and they sure are fun to fly.

All the Best!

Cheers,

db

 

[Tom Finch]

a 9a with an 0320 and a Hartzell cs (Vans recommendation) or a 9a with an 0360 and a Catto 3 blade composite fp.

The O360 is

over $4000 less cost, 35 lbs less wt, better cruise capability, similar climb capability, less engine stress, lower noise, less complexity/maintenance, and smooth operation-----yea, faced with the same two options I would most likely do it again!!

RV9a/ECi0360/James Cowl/Catto Prop
Flying since 3/06 and still smiling!!!

That sounds like a good idea........................

 

[Mel]

F/P vs C/S

BTW, my original post about my RV-6 taking off at Leadville with a tired 150 hp Lycoming in the summer with no problem, was with a fixed pitch wood prop! So; even though C/S props are nice, they are NOT necessary.

 

[rtry9a]

I don't think the point is whether an RV can get off the ground in the high country of the West- we know that all models perform beautifully wherever and whenever.

The real question is how big does the engine have to be (ie, 320 vs 360/ equivalent) to produce the HP that the airframe was designed for at higher elevations. The flying envelope is different if one is based at or near sea level, like most pilots are, vs being located in God's country where the air is thinner. The way I seen it is it simply does not hurt to have extra power available as long as the airspeed up high is controlled- it is occasionally desired in some situations and irrelevant in most.

IMHO, the 9's wing is a big advantage here (in Utah)- from what Ive seen in the local EAA meetings, Id guess the 9's being built/flown outnumber the 7 models 2:1. On the coasts, I'm sure its is the other way around.