What's new
Van's Air Force

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

Subjective question on turbulence. When do you personally slow down?

jcarne

Well Known Member
Patron
I have been talking to other pilots about turbulence lately and it seems everyone's take on it is slightly different. In our RVs we cruise quite fast which leads to my question. When do you guys personally find it is time to slow down?

I for one am not bothered by good amounts of turbulence and and can take quite a bit. However, passengers don't necessary share the same viewpoint and ultimately I'm curious when it should be considered the prudent thing to do in our RVs. Yes, there are things to avoid to stay clear of the nasty stuff but the bumps are unavoidable at times.

What's your approach?
 
I back off on power/speed when I start getting concerned about bouncing my head off of the canopy. That can be uncomfortable and can damage things. Worst case, it can be incapacitating.
 
head bashing

I had this same question put before me a few years back.
My answer was " if you bash your head hard enough on the canopy it will knock some sense into you. That is, You should have been slowing down before the head bashing."
The guy just laughed as I did also.
Have had my head bashed when I wasn't even in turbulence. Them sneaky bumps are out to get you.
I like my head. So I slow down appropriately. NO hard rules here.
My three cents worth and not a penny more.
Art
 
From a structural perspective, slow to manuevering speed when you're in turbulence sufficient to approach the G-limits of the airplane.

From a personal comfort perspective, ask a hundred people and get a hundred answers.

Turbulence doesn't bother me until I start bouncing my head off the canopy - then I know I'm about 2 minutes late pulling the power back. On a cross-country I usually cruise high enough that my IAS is pretty close to manuevering speed anyway, and turbulence up there is considerably reduced unless you're in mountain wave. I've had a few exceptions though...
 
Glad to see I'm not the only one that thinks head bashing is the pull power point. haha

It happened to me once in phase 1 and it was just a random one that day. Since then I always keep my harness fairly tight too. Luckily those Crows are pretty dang comfy.
 
My RV-3 cruises much closer to Vne than Va, so I'm pretty aware of turbulence. If it's the standard summer lumpity-bump stuff, I'll press on and slow from maybe 170ktas to around 155ktas. If it's serious, frontal-based stuff where I've cinched my belts down and I'm still concerned about bashing my head, then I'll slow way back to around 130ktas.

Not long after I purchased my RV-3, I followed a very experienced RV-7a pilot to and from Granby (KGNB) airport--over the first big mountains west of the Denver/Boulder area. His policy was to clear the mountains by a wide margin and if the winds at altitude were more than 15 knots in any direction, he slowed to Va until well clear of the mountains. I think this is pretty solid advice.

I got popped really good during the summer of 2020 when I was running high power settings at low altitude to break in a new engine. There was a little "wiggle" of a bump just enough to make me consider starting to slow down and then before I could act on the thought, I really got smacked. Felt like a direct top-to-bottom blow. My head hit the canopy so hard that I actually expected to see cracks in the canopy.

Of course, I'm single-seat, so passenger considerations aren't an issue, but slower speeds sure do make the bumps more tolerable.
 
Head Bouncing

+1 on getting head-bounced. Did it a couple of years ago in ZERO turbulence, and it almost knocked me out. Luckily I was only 10 from the airport, which I made with a splitting headache. Subsequently, I'm a big believer in 5 point harnesses, which I now keep tight somewhere between uncomfortable and unbearable. If I can move at all, they are too loose for me now. Also (off topic), I never listen to music while flying. I just may miss some important piece of information that may save my bacon later. Too distracting! YMMV.
 
Last edited:
mountain leeward wind side

the worst turbulence I have experienced is mountain waves on the leeward wind side 10 to 20 miles down range. it's bad when you're holding the base of both sticks and still banging your head. I give them a wider berth now.
 
Our RVs can take more bouncing around than I can. And I agree, slow down before you bang your head on the canopy.

I would be more concerned with your passenger, especially if they don't have many miles under their belt. Look at your passengers to see their reaction and if they have white knuckles slow down or land. Ask if they are ok, suggest "if we slow down it will be smother." or just slow down and spend an extra 10 minutes flying.
 
Vne in turbulence is not a great idea and could exceed structural limits.
Va maneuvering speed in turbulence may be a bit slow but safe. (142 mph RV7)
Vno is maximum structural cruise speed (this would your max speed in turbulence less than severe or extreme (193 mph RV7)

PIC judgement.
If turbulence is light, light chop slow to econ cruise if not already at econ cruise (under 180 mph or less)
Moderate turbulence / chop. small change in altitude but under control slow to 180-142 mph
Severe or extreme turbulence slow to Va or less and look for an out. 142 mph.
 
Last edited:
turbulence

From the FAA:

Light turbulence momentarily causes slight changes in altitude and/or attitude or a slight bumpiness. Occupants of the airplane may feel a slight strain against their seat belts.

Moderate turbulence is similar to light turbulence but somewhat more intense. There is, however, no loss of control of the airplane. Occupants will feel a definite strain against their seat belts and unsecured objects will be dislodged.

Severe turbulence causes large and abrupt changes in altitude and/or attitude and, usually, large variations in indicated airspeed. The airplane may momentarily be out of control. Occupants of the airplane will be forced violently against their seat belts.

In extreme turbulence, the airplane is tossed violently about and is impossible to control. It may cause structural damage.

(Emphasis added)

As these definitions are definitely subjective, when someone reports severe or extreme turbulence, I wonder if the airplane was actually out of control.

Slowing down is a good thing...and being proactive about it is also a good thing...
 
Real scary? 2x stall speed or less.

Square root of the g factor is the increase in stall speed multiple.

4g gust should stall the wing before anything breaks.

Reversal from gusts are not like snooth aerobatics.
 
From a structural perspective, slow to manuevering speed when you're in turbulence sufficient to approach the G-limits of the airplane.

From a personal comfort perspective, ask a hundred people and get a hundred answers.

Turbulence doesn't bother me until I start bouncing my head off the canopy - then I know I'm about 2 minutes late pulling the power back. On a cross-country I usually cruise high enough that my IAS is pretty close to manuevering speed anyway, and turbulence up there is considerably reduced unless you're in mountain wave. I've had a few exceptions though...

Since the RV9/9A Va is 118 MPH TAS you are flying high enough that your IAS comes down to that speed? So, what do you find is that altitude, typically?

My answer to the OP question of “what do you do?”, I will climb to an altitude that gets me out of the turbulence. That works the majority of the time, especially since our machines can climb so quickly it really is easier to just climb out of it. If I cannot escape then it is time to slow down to the Vans published Vno that gmcjetpilot mentioned. He gave numbers for the RV7. For the RV9/A that is a max airspeed around 160 MPH TAS. Honestly, my number is really 150 MPH TAS.

This article has been out quite a while but is always valuable information for all RV9/A pilots: https://www.vansaircraft.com/wp-content/uploads/2019/01/hp_limts.pdf

Study the graphic on page 4.
 
Last edited:
From the FAA:

Light turbulence momentarily causes slight changes in altitude and/or attitude or a slight bumpiness. Occupants of the airplane may feel a slight strain against their seat belts.

Moderate turbulence is similar to light turbulence but somewhat more intense. There is, however, no loss of control of the airplane. Occupants will feel a definite strain against their seat belts and unsecured objects will be dislodged.

Severe turbulence causes large and abrupt changes in altitude and/or attitude and, usually, large variations in indicated airspeed. The airplane may momentarily be out of control. Occupants of the airplane will be forced violently against their seat belts.

In extreme turbulence, the airplane is tossed violently about and is impossible to control. It may cause structural damage.

(Emphasis added)

As these definitions are definitely subjective, when someone reports severe or extreme turbulence, I wonder if the airplane was actually out of control.

Slowing down is a good thing...and being proactive about it is also a good thing...

I keep those exact descriptions on a piece of paper so I can periodically review them before a PIREP. I don’t want to be the guy that reports moderate when it wasn’t and so forth. Great little reminder from time to time.
 
Turbulence is subjective between different models. Light wing loading and a stiff spar will feel the bumps. A flexible highly loaded wing will ride through the bumps a lot smoother. My point, when reading PIREPs and talking to other pilots, consider the plane they were flying. What rattled the teeth out of a 172 pilot might be a minor ripple in a Boeing 787. So if you or I reads "moderate turbulence on departure from KXYZ from Boeing 787", maybe don't take a RV into there until the conditions improve.

I can't seem to find the source anywhere, but I seem to recall airspeed fluctuations being part of moderate turbulence.
 
In the RV-9A, from experience, I slow down before entering a cumulus cloud (IFR, of course) that's more than about 4,000 feet, top to bottom. In one situation, where there was more vertical development than that and I knew from watching the ADS-B that I would not be in the clouds for long, I slowed to 100 knots.

There's also cumulative effects of turbulence on the pilot. A full day of bump, bump, bump across the desert southwest can really take it out of you. Fatigue makes you more susceptible to stress increases the odds of poor decision making.

As with many things, best to work your tolerance up gradually and stop before you reach your limits rather than jump right in and hope for the best. Hope is a poor strategy...
 
Personal Definitions.

Severe turbulence - - - when cinched tight in a 5-point harness your head gets bashed.

Extreme turbulence- - - and bloodied.

Note to self: Cinch 5 points tight…..

Happy New Year
 
Personal Definitions.

Severe turbulence - - - when cinched tight in a 5-point harness your head gets bashed.

Extreme turbulence- - - and bloodied.

Note to self: Cinch 5 points tight…..

Happy New Year

I Have a friend that flies a C-414. One time he was flying to L35 (Big Bear) with his family and SoCal approach asked him for a Pirep as two other planes turned around due to Turb. He turned around too....

- Marc
 
Since the RV9/9A Va is 118 MPH TAS you are flying high enough that your IAS comes down to that speed? So, what do you find is that altitude, typically?

Close.

102 knots is 118mph, which is Va for 9A. See below for a typical cross-country cruise for me.
 

Attachments

  • screenshot-N16GN-SN13208-16.0.4.8437-20211124-152633-695-en_US.png
    screenshot-N16GN-SN13208-16.0.4.8437-20211124-152633-695-en_US.png
    691.2 KB · Views: 156
Personal Definitions.

Severe turbulence - - - when cinched tight in a 5-point harness your head gets bashed.

Extreme turbulence- - - and bloodied.

Note to self: Cinch 5 points tight…..

Happy New Year

haha I like it!

Close.

102 knots is 118mph, which is Va for 9A. See below for a typical cross-country cruise for me.

Dang Greg, I thought I liked to cruise high with my 12,500 runs. I'll join the ranks as soon as I get an O2 system installed. Love being up high. Although I'm betting your -9A wing does better up there.
 
After reading these posts I realize I am a wuss when it comes to bumps. I really dont enjoy flying if I am getting bounced around. Im still working on my license so maybe I just need some more experience. When my friend and I flew out to MI from ID it was as bumpy as I care to fly in going over the Rockys.

I guess the light plane and big wing make it a good target to get bounced around!
 
Close.

102 knots is 118mph, which is Va for 9A. See below for a typical cross-country cruise for me.
Thanks for the reply. I had a feeling the altitude would have to be quite high to get the IAS down to 118 mph. As I mentioned in my post, I tend to pay attention to TAS for all of my flying except when low and slow. Down low in the pattern I will change my focus to the IAS, especially for flap deployment in the pattern.
 
Last edited:
After reading these posts I realize I am a wuss when it comes to bumps. I really dont enjoy flying if I am getting bounced around. Im still working on my license so maybe I just need some more experience.

Experiencing more bumps doesn't make them any more enjoyable. Just sayin'

-Marc
 
If I have trouble pushing button on the panel it is time to slow down.

Indeed - - or climb. I was approaching 10k mountains, 27 kt headwind at 12000 and getting beat up with strong chop. Very hard to push buttons, but asked for higher, cleared for 14 and got relief 90% at 12.4.

If not successful, slower was the next option. Pretty uncomfortable after a bit, probably a shorter time than it seemed. But - - not enough to kick off the AP.
 
I’ve got a ton of time flying mountains and to be honest after 50 years of getting beat up from time to time in some pretty good turbulence I’ve never gotten used to it and I never will. It’s just not something to get used to…it might not even be wise..think our brains are talking to us.:)
 
Looks like your Va is set to 118 KIAS instead of 118 MPH IAS (The "A" tick mark on the SkyView speed tape).

True enough, it is. I don't pay much attention to the tape colors though, I don't find them as useful as some others do. I fly by the numbers.

haha I like it!



Dang Greg, I thought I liked to cruise high with my 12,500 runs. I'll join the ranks as soon as I get an O2 system installed. Love being up high. Although I'm betting your -9A wing does better up there.

The 9A wing does love it up there - and having an IO360 with a constant speed prop just makes it so easy.
 
Last edited:
When do you guys personally find it is time to slow down?

For me it is dependent on the flight regime.

In level cruise flight, if I am operating at any IAS above Vno (the start of the yellow arc), I reduce speed to be at or below Vno at the first indication of turbulence.

If in cruise flight and already at or below Vno IAS, I reduce to a speed that the ride is tolerable. If the turb. is what I would consider constantly moderate, I will slow to something closer to Va (if turb. is already moderate, you never no how many seconds away you are from something that is really bad).

When in a decent I always limit max. IAS to Vno... when descending through air-mass layers, you never know when a bad bump is going to occur. Just because it was smooth at your cruise altitude, doesn't mean it will be all the way down.

Aside from those procedures, I will usually do what ever it takes to make the ride tolerable buy making an altitude or route change. Even if it will add an appreciable amount of additional time to the flight. I place a much higher value on how I (and even more so my passengers, if I have any) feel when I arrive at my destination, than I do on when I will arrive.
 
The occasional severe, sharp-edged bump can really slam my head against the canopy (I've got about 2in between the canopy and headset). A few times I've yanked off the co-pilot's seat back cushion and jammed it between my head and the canopy because I've been concerned about breaking either the canopy or my head. Considering a piece of closed-cell foam to have handy to do this. The -14 lap belt anchors are too far back to arrest vertical motion and the crotch strap only helps a little bit. I installed an additional ratcheting belt with anchors further forward and this helps a lot (great for aerobatics too).

IMG_0662x.jpg

IMG_0701x.jpg
 
For me it is dependent on the flight regime.

In level cruise flight, if I am operating at any IAS above Vno (the start of the yellow arc), I reduce speed to be at or below Vno at the first indication of turbulence.

If in cruise flight and already at or below Vno IAS, I reduce to a speed that the ride is tolerable. If the turb. is what I would consider constantly moderate, I will slow to something closer to Va (if turb. is already moderate, you never no how many seconds away you are from something that is really bad).

When in a decent I always limit max. IAS to Vno... when descending through air-mass layers, you never know when a bad bump is going to occur. Just because it was smooth at your cruise altitude, doesn't mean it will be all the way down.

Aside from those procedures, I will usually do what ever it takes to make the ride tolerable buy making an altitude or route change. Even if it will add an appreciable amount of additional time to the flight. I place a much higher value on how I (and even more so my passengers, if I have any) feel when I arrive at my destination, than I do on when I will arrive.

Scott, thanks for the reply. I really like that approach. Being in the yellow gives me the bad tingles, especially on decent as well; I generally stay out of it all together as I like my wallet to stay a little fuller. :)

The occasional severe, sharp-edged bump can really slam my head against the canopy (I've got about 2in between the canopy and headset). A few times I've yanked off the co-pilot's seat back cushion and jammed it between my head and the canopy because I've been concerned about breaking either the canopy or my head. Considering a piece of closed-cell foam to have handy to do this. The -14 lap belt anchors are too far back to arrest vertical motion and the crotch strap only helps a little bit. I installed an additional ratcheting belt with anchors further forward and this helps a lot (great for aerobatics too).

View attachment 20369

View attachment 20370

Interesting, never seen that done before. Cool idea.
 
Me too

Yup, every now and then there is just no way to go around the tall bumpy ones. I always slow down. I reason that I’m usually still going faster than my old Warrior. :)

In the RV-9A, from experience, I slow down before entering a cumulus cloud (IFR, of course) that's more than about 4,000 feet, top to bottom. In one situation, where there was more vertical development than that and I knew from watching the ADS-B that I would not be in the clouds for long, I slowed to 100 knots.

There's also cumulative effects of turbulence on the pilot. A full day of bump, bump, bump across the desert southwest can really take it out of you. Fatigue makes you more susceptible to stress increases the odds of poor decision making.

As with many things, best to work your tolerance up gradually and stop before you reach your limits rather than jump right in and hope for the best. Hope is a poor strategy...
 
The occasional severe, sharp-edged bump can really slam my head….
Considering a piece of closed-cell foam to have handy to do this.
Passenger: What’s that foam for?
Me: Let’s hope I don’t have to demonstrate….

Happy New Year
 
When in a decent I always limit max. IAS to Vno... when descending through air-mass layers, you never know when a bad bump is going to occur. Just because it was smooth at your cruise altitude, doesn't mean it will be all the way down.

Except when descending from altitudes above about 10,000' (the crossover altitude for the -8s and -7s), where Vne is less than Vno and makes Vno irrelevant. ;)

Vne and Vno are about equal at about 10,000':

i-Nq7JcgK-M.png


Above about 10,000' Vne is less than Vno, so Vne governs:

i-5csHKL5-M.png


Any progress on getting out that SB or SL which will officially state that Van's changed the Vne definitions from IAS to TAS for the older models (that critical safety-of-flight information)? :rolleyes:
 
Last edited:
For me it is dependent on the flight regime.

In level cruise flight, if I am operating at any IAS above Vno (the start of the yellow arc), I reduce speed to be at or below Vno at the first indication of turbulence.

If in cruise flight and already at or below Vno IAS, I reduce to a speed that the ride is tolerable. If the turb. is what I would consider constantly moderate, I will slow to something closer to Va (if turb. is already moderate, you never no how many seconds away you are from something that is really bad).

When in a decent I always limit max. IAS to Vno... when descending through air-mass layers, you never know when a bad bump is going to occur. Just because it was smooth at your cruise altitude, doesn't mean it will be all the way down.

Aside from those procedures, I will usually do what ever it takes to make the ride tolerable buy making an altitude or route change. Even if it will add an appreciable amount of additional time to the flight. I place a much higher value on how I (and even more so my passengers, if I have any) feel when I arrive at my destination, than I do on when I will arrive.
That's a really great strategy Scott, consider it stolen! :D

Thanks!

Dave
 
Any progress on getting out that SB or SL which will officially state that Van's changed the Vne definitions from IAS to TAS for the older models (that critical safety-of-flight information)? :rolleyes:

Yes Carl, there actually is :rolleyes:

In fact work has been being done on updating and expanding Section 15 in the manual for application to all models, but I don't have any info on when that will be released.
 
Yes Carl, there actually is :rolleyes:

In fact work has been being done on updating and expanding Section 15 in the manual for application to all models, but I don't have any info on when that will be released.

Glad to hear that Scott. It's been a long time in coming, too long in fact.

An SL first would have been a much faster method to get that critical safety-of-flight information out to as many RV owners/pilots as possible (and may still be!). Then afterward update Section 15 as time allowed, as was done for the RV-14's.

"For those familiar with RV kits, this will replace the information usually found in Chapter 15 (Final Assembly & Flight Test)."
 
Last edited:
Back
Top