What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

IFR Flight Characteristics: RV-8 vs RV-9

flyboy10

Member
I'm looking for guidance on the flight characteristics and separately, build differences in the 8 and 9.

Van's touts the 9 for being fast, and a great cross country cruiser, IFR machine, etc. Yet on the spec sheets (are those even accurate?) the 8 is just as good or better in every regard.

1. For IFR flying, is the 8 that much different than the 9?
2. Is building one harder than the other?

Let's set aside aerobatics, tandem seating, etc.
 
If you have never built one of Vans RVs then you won't find any major differences. Some areas will be difficult for you and other areas very easy. Building any one of these planes will cause you to experience pretty well every emotion known to mankind. But the finale and the greatest emotion experienced will be the day you are flying the plane that you actually built with your own hands.
 
Thanks Norman. I see that Vans made changes to the plans in later aircraft. I'm admittedly not the best with interpreting drawings and instructions. Is it a considerable difference with the newer aircraft? At first glance on the Van's site, it is, but nothing beats real world knowledge.
 
The plans for the 10/12/14 are step by step, detailed plans with drawings and instructions right there on the page. For the 7/8/9 kits, the drawings are large sheet sized and the instructions are in a 3-ring-binder style book, and not quite as detailed as the newer models.

The other significant difference is that the newer models (above) are a bit more refined/finished-state parts, so they build a bit faster (especially the 12 and 14).

They're all quite doable. You can download and look at some of the plan's sections if you visit the Support > Safety & Service Info section for each airplane. Look in the "Revisions and Changes" section for each model for samples.

The RV-8 and RV-9 are fairly similar in terms of being an IFR platform. The RV-8 wing is a bit sportier and the RV-9 wing is a thicker, efficient airfoil intended to maximize performance at altitude on lower power engines (specifically, the 320-series). The -8 is aerobatic, and the -9 is not.
 
Last edited:
when I measured the spar height of the 8 and the 9, they appeared to be the same. is that true?
 
Since you've asked us to set aside the primary differences between these two airplanes, and one of these threads went sideways yesterday because many very experienced folks tried to point out factors that that original poster didn't want to hear about, I'll respect your choice and simply say that while I have some time in many other RVs but none in the -9s, the 9 is intended to be a cross-country machine, stable and comfortable. (I do own and fly a -7A which is essentially a -9A with a different wing.) The RV-8 is intended to be more "fun", and it's certainly capable of being so.

A quick search of these forums indicate that many people are quite comfortable flying suitably equipped aircraft of either type in IMC which is appropriate for capable and current instrument pilots in light, single engine aircraft.

Both kits are available in Standard and Quickbuild, though the RV-8 design is about five years older than the -9 design. Never having built either one, I can't say for sure, but I would imagine that build time and complexity are not terribly different. I've been told that the tandems are a little bit easier to build than the side-by-sides, but perhaps someone who's built both will chime in. (It looks like Greg from Van's has chimed in while I was writing. He probably knows as well as anyone.)

I would suggest that you try to fly them both, then build what you want and need to fly. Flying what you wanted to build instead might leave you wanting in the long run. On the other hand, there are plenty of folks who get just as much satisfaction from building as they do from flying, so they become serial builders. (You could build more than one!)

If you build it, you get to have your own perfect version of whatever you choose. I found my version of perfect after someone had already built it, and since I know I don't have time to build, I didn't, but sometimes I wish I did, and someday I might.

Good luck, and welcome.
 
Last edited:
Both kits are available in Standard and Quickbuild, though the RV-8 design is about five years older than the -9 design. Never having built either one, I can't say for sure, but I would imagine that build time and complexity are not terribly different. I've been told that the tandems are a little bit easier to build than the side-by-sides, but perhaps someone who's built both will chime in. (It looks like Greg from Van's has chimed in while I was writing. He probably knows as well as anyone.)

The RV-7/8/9 are all quite similar in build style, technique and time.

I would suggest that you try to fly them both, then build what you want and need to fly. Flying what you wanted to build instead might leave you wanting in the long run.

^^ This is good advice.
 
I think maybe the answer you are looking for is that the 9 is considered to be a little more stable. It has a slower roll rate and a slower stall speed.
Therefore often considered a better IFR machine.
There are many RV-8's flying IFR.
Since many more machines are using autopilot now days that is often a moot point.
I wanted IFR stable so I picked the 9 but wanted sporty so built it as a tailwheel.
 
Nobody has really addressed handling qualities for IFR, so I might as well give it a go. "Fools rush in..."

I've got 367 hours in my IFR-equipped RV-9A and fly it IFR. Combined time in my RV-8 and RV-8A was 135 hours, neither one flown IFR although the -8 at one point before I bought it was IFR equipped. (Also 355 RV-4 hours). It's been a while since I sold the -8, so...

1. Hand flying in only very slightly choppy air, the -9 will deviate less from intended flight path and will require less attention to hand fly precisely.
2. Inside a cumulus cloud, even one with a vertical development of only three or four thousand feet, the RV-9A will take you for a *ride*, with serious pitch and roll deviations. I don't have comparables for a -8, but I think it would be better. Solution in the -9A is to slow way down.
3. The -8/A, as an aerobatic airplane, will respond more quickly to small control inputs than the -9. For a while, the Van's website said that the -9 handling was more "laid back..." They were quoting a pilot report that I wrote. I'd like to express this in pole/zero terminology to be more descriptive, but I took those classes nearly 50 years ago. Sigh...
4. As previously discussed in other posts, the -9 has an awful ride in bumpy air out west. Although I flew the -8 and -8A on very long X-Cs to bring them home, I don't know that I ever encountered comparable weather, so no real comparison. They were flown for fun in VMC, whereas the -9A has been used more on deliberate trips with different go/no go criteria.

As for flying either one IFR:
1. Years ago, a multi-RV, 6,000 hour RV pilot said that RVs were fine IFR if you never had to do any paperwork, like look at a chart or write a clearance. This was back in the RV-4/6 days.
2. An autopilot really makes life easier for IFR in an RV, especially if you have a glass cockpit and are messing around with all the various screens. Then again, an autopilot is not a panacea as you need to monitor it closely to make sure that it's really doing what you thought you asked it to do.
3. Even if you have an autopilot, you need to be able to hand fly IFR, just in case.

And a last comment on what other pilots will state. And by way of background, I've published something over 100 pilot reports and at one point thought I had my act together for handling qualities evaluations:
1. There is rampant dysfunctionality when pilots discuss their own airplanes. Almost nobody can make a distinction between "I really like the ownership experience I've had" and "This plane has great handling qualities from an objective, engineering point of view."
2. Pilots are highly adaptable and most pilots quickly learn to fly whatever they're in, regardless of handling qualities.
3. Very few pilots are aware of handling qualities. I've flown with a number of factory demo pilots who were excellent sticks but had absolutely no idea how the plane handled objectively or, in one case, of what techniques they used flying the plane.

So what's the best advice?
1. When I was working on my ATP, my instructor said, "Instrument flying is war." In other words, bring your A game, all the time, and if you don't have an A game flying IFR in an RV...
2. There's a good chance that if you fly both the -8 and the -9, you won't be able to tell the difference.
3. Frankly, I don't know how much real world difference there would be between the two. RV-9A for handling qualities, RV-8 possibly for ride in turbulence, RV-9A for more cockpit and panel space and tricycle gear makes it easier to land in an ugly crosswind when you're beat up after a day of hard flying. (Yes, you said -9 and not -9A).
4. To thine own self be true. There will always be other pilots who can easily do things that aren't easy for you and will misuse that personal skills assessment as a measure of the airplane.

Make your best decision and either live with that decision or sell the plane. In my case, that decision is that I'm very circumspect in what weather I'll fly in, VFR or IFR, considering ride quality/fatigue as major factors.
 
Last edited:
I have built a -8 and -9 standard build. The build the same these days (-8 pre-punched).
 
If you have never built one of Vans RVs then you won't find any major differences. Some areas will be difficult for you and other areas very easy. Building any one of these planes will cause you to experience pretty well every emotion known to mankind. But the finale and the greatest emotion experienced will be the day you are flying the plane that you actually built with your own hands.
 
Nobody has really addressed handling qualities for IFR, so I might as well give it a go. "Fools rush in..."

Hey thank you for that write up, Ed. I didn't spawn this thread, but I was involved in the one that went off the rails yesterday. Your advice today is artful, and composed in a way that both profers much experience and encourages careful consideration.

I think you just made a better pilot out of me, or more accurately, helped me think about making a better pilot out of myself.

Blueskies.
 
Last edited:
Both great planes, I own a 9 but fly in 8's also.

To me IFR says if another pilot can be with me for the flight to help, that is very welcome. In the 8, the back seat won't be as helpful as the passenger seat in the 9 would be.

9 would also give more room for ipads, paperwork single pilot.

7 would be a good middle ground also.

But you just can't go wrong on the Van's designs, regardless.
 
Never flown a 9, but did do my IFR training and regularly flew IFR in the 6A (should handle VERY similar to an 8). In my experience, the rolling / heading is not the challenge; It is the pitch sensitivity of the 6 that requires constant attention. I have no idea how much more or less stable the 9 is in pitch.

If IFR is important, I would be looking at differences in pitch sensitivity and response to turbulence (have seen some postings here implying that the 9 more challenging in turbulence). These are the two things that most impact IFR comfort IMHO. Given that I couldn't really use the AP in training, I can say that IFR without an AP can be mentally taxing and wouldn't recommend it for long fligts. I learned quickly that your eyes cannot move away from the instruments for more than 10 seconds at a time. Things like setting up and briefing approaches must be done in small increments. VERY different than a spam can that will chug along in the same path without much attention.

Larry
 
Last edited:
Even the most experienced instrument pilots only spend about 10% of their time in actual IMC, couple this with an AP and flying differences between the aircraft become almost null regarding IFR flight.
 
Great points! And you're hitting on one which is my question is largely subjective.

As some here have suggested, I think the answer lies in a test flight. I appreciate the time everyone has spent on these replies. Thank you.
 
Even the most experienced instrument pilots only spend about 10% of their time in actual IMC, couple this with an AP and flying differences between the aircraft become almost null regarding IFR flight.

Yes... until the autopilot malfunctions and must be disengaged. It hasn't happened to me in a meaningful way other than a quick toggle when an autopilot has as run out of trim, but I've read of many instances in which an autopilot must be disabled, or does so in an uncommanded fashion.

Personally, I always plan for contingencies by assuming the autopilot is inoperative. I'm also a firm believer that single pilot instrument operations are to be avoided. I'm a bit conservative, I suppose.
 
Last edited:
Nobody has really addressed handling qualities for IFR, so I might as well give it a go. "Fools rush in..."

I've got 367 hours in my IFR-equipped RV-9A and fly it IFR. Combined time in my RV-8 and RV-8A was 135 hours, neither one flown IFR although the -8 at one point before I bought it was IFR equipped. (Also 355 RV-4 hours). It's been a while since I sold the -8, so...

1. Hand flying in only very slightly choppy air, the -9 will deviate less from intended flight path and will require less attention to hand fly precisely.
2. Inside a cumulus cloud, even one with a vertical development of only three or four thousand feet, the RV-9A will take you for a *ride*, with serious pitch and roll deviations. I don't have comparables for a -8, but I think it would be better. Solution in the -9A is to slow way down.
3. The -8/A, as an aerobatic airplane, will respond more quickly to small control inputs than the -9. For a while, the Van's website said that the -9 handling was more "laid back..." They were quoting a pilot report that I wrote. I'd like to express this in pole/zero terminology to be more descriptive, but I took those classes nearly 50 years ago. Sigh...
4. As previously discussed in other posts, the -9 has an awful ride in bumpy air out west. Although I flew the -8 and -8A on very long X-Cs to bring them home, I don't know that I ever encountered comparable weather, so no real comparison. They were flown for fun in VMC, whereas the -9A has been used more on deliberate trips with different go/no go criteria.

As for flying either one IFR:
1. Years ago, a multi-RV, 6,000 hour RV pilot said that RVs were fine IFR if you never had to do any paperwork, like look at a chart or write a clearance. This was back in the RV-4/6 days.
2. An autopilot really makes life easier for IFR in an RV, especially if you have a glass cockpit and are messing around with all the various screens. Then again, an autopilot is not a panacea as you need to monitor it closely to make sure that it's really doing what you thought you asked it to do.
3. Even if you have an autopilot, you need to be able to hand fly IFR, just in case.

And a last comment on what other pilots will state. And by way of background, I've published something over 100 pilot reports and at one point thought I had my act together for handling qualities evaluations:
1. There is rampant dysfunctionality when pilots discuss their own airplanes. Almost nobody can make a distinction between "I really like the ownership experience I've had" and "This plane has great handling qualities from an objective, engineering point of view."
2. Pilots are highly adaptable and most pilots quickly learn to fly whatever they're in, regardless of handling qualities.
3. Very few pilots are aware of handling qualities. I've flown with a number of factory demo pilots who were excellent sticks but had absolutely no idea how the plane handled objectively or, in one case, of what techniques they used flying the plane.

So what's the best advice?
1. When I was working on my ATP, my instructor said, "Instrument flying is war." In other words, bring your A game, all the time, and if you don't have an A game flying IFR in an RV...
2. There's a good chance that if you fly both the -8 and the -9, you won't be able to tell the difference.
3. Frankly, I don't know how much real world difference there would be between the two. RV-9A for handling qualities, RV-8 possibly for ride in turbulence, RV-9A for more cockpit and panel space and tricycle gear makes it easier to land in an ugly crosswind when you're beat up after a day of hard flying. (Yes, you said -9 and not -9A).
4. To thine own self be true. There will always be other pilots who can easily do things that aren't easy for you and will misuse that personal skills assessment as a measure of the airplane.

Make your best decision and either live with that decision or sell the plane. In my case, that decision is that I'm very circumspect in what weather I'll fly in, VFR or IFR, considering ride quality/fatigue as major factors.


Great points! And you're hitting on one which is my question is largely subjective.

As some here have suggested, I think the answer lies in a test flight. I appreciate the time everyone has spent on these replies. Thank you.
 
Good point

My autopilot in my -9A took a nap on me one day as I was doing a climbing turn into a bouncy bouncy cumulus cloud north of Philly, in VFR weather. I’ve got the older 307 box with a G5, so there was no audible warning, just the little flashing yellow A. Not a great setup. On this occasion it was easy to notice that something had gone wrong, however. :) I was quickly reminded that keeping a -9A on track in cumulus by hand is a full time job. Maybe there are some Ernest Ganns out there who can do it without breaking a sweat, but I’m not one of them.

The 9 does many things well, but it is really not an ideal airplane for instrument flying, in my opinion. When flying by hand, it really isn’t much worse on approaches than my Warrior was - the 9A is not as stable, but the big EFIS display (which I didn’t have in the Warrior) seems to help quite a bit. I theorize that it lets me notice deviations more quickly. Hand flying in cruise, however, Warriors, 172s, and basically every other mainstream certified plane I’ve flown beat the 9 by a mile.

As a result my personal IFR minimums are basically marginal VFR, and I try to avoid cumulus. For me, IFR in the 9 is mostly about simplifying trip planning and execution, not spending hours in IMC. A little cloud surfing along the way is a bonus, and once in a while you need to slow down in cumulus or turbulence. :)

Yes... until the autopilot malfunctions and must be disengaged. It hasn't happened to me in a meaningful way other than a quick toggle when an autopilot has as run out of trim, but I've read of many instances in which an autopilot must be disabled, or does so in an uncommanded fashion.

Personally, I always plan for contingencies by assuming the autopilot is inoperative. I'm also a firm believer that single pilot instrument operations are to be avoided. I'm a bit conservative, I suppose.
 
Yes... until the autopilot malfunctions and must be disengaged. It hasn't happened to me in a meaningful way other than a quick toggle when an autopilot has as run out of trim, but I've read of many instances in which an autopilot must be disabled, or does so in an uncommanded fashion.

Personally, I always plan for contingencies by assuming the autopilot is inoperative. I'm also a firm believer that single pilot instrument operations are to be avoided. I'm a bit conservative, I suppose.

No argument from me...one certainly needs to be proficient but said proficiency has very little to do with the flying differences between an -8 and -9. If I were buying/building I would be more concerned about how the ship was equipped
 
Last edited:
Back
Top