Hi, this is my first post and I'm hoping Patty could answer a question I've been wanting to ask for some time.

As I understand, you don't wear a G suit for your performances as someone flying a military Jet would. I was wondering what kind of G's you pull (max G) and at what duration in a typical routine. I was also hoping you could tell me what exercises you do to strengthen those muscles... and if it's possible to describe in writing, what muscles to flex and how during sustained Gs.

Ryan

• RE: Aerobatics and G forces,TomParsons, 16:53z, 05-14-03
  • RE: Aerobatics and G forces,Ben_Chiu, 19:21z, 05-14-03
    • RE: Aerobatics and G forces,Ben_Chiu, 19:29z, 05-14-03
• RE: Aerobatics and G forces,TomParsons, 20:19z, 05-14-03
  • RE: Aerobatics and G forces,Ben_Chiu, 17:29z, 05-15-03
  • RE: Aerobatics and G forces,djpacro, 10:46z, 05-18-03
• RE: Aerobatics and G forces,Patty_Wagstaff, 13:35z, 05-16-03
• RE: Aerobatics and G forces,apgherm, 01:26z, 05-18-03
  • RE: Aerobatics and G forces,djpacro, 03:15z, 05-20-03
• RE: Aerobatics and G forces,DRAGON13, 13:51z, 03-18-06
  • RE: Aerobatics and G forces,Patty_Wagstaff, 00:35z, 03-25-06

Since it's been a week with no replies, I'll jump in with a guess or two, even though Patty, Dale, Dave P, and many others could answer much better...

From what I have read and heard, I would guess that the range of G forces the pilot sees in a top air show routine goes from +9G or so to about -7G. BTW, just for reference, positive Gs are where you are being pushed into the seat (blood pooling in your feet), while negative Gs are pushing you into the seat belt and shoulder straps (blood rushing into your head).

There are a couple of differences between the aerobatic/air show pilots and military pilots in terms of the way they pull Gs. First, military jet flying subjects the pilot to much smaller negative Gs than your average air show routine does. And the G-suit does nothing to help with that. Second, the maximum G forces on an air show pilot are probably of much shorter duration than a military jet pilot sees.

The muscle flexing to combat positive Gs is intended to make it harder for blood to drain away from your head. The progression is not unlike squeezing toothpaste from a tube, where you start at the bottom and squeeze your way up. You'd start by tightening your calves, then move to the thighs, then maybe do an internal abdomen tightening or straining as if you were trying to forcibly exhale but holding your breath. You can do more or less of that progression as the level of G force dictates.

For negative Gs, I have no direct experience. But I have read that no kind of muscle tightening is going to help; in fact, it may actually make things worse. I'm told that you just gotta relax...

Because of the benefits of muscle strength in holding back the blood flow during tightening, I've read that some anaerobic strength-type training is good to do. But I also know that all that straining, yanking, banking, and cranking gets you tired pretty fast, so good overall aerobic fitness is needed to fly an extended aerobatic routine.

Well, we have gone up to and beyond my understanding of this subject! Hope this helps. Anybody else ready to chime in with a more authoritative answer?

Tom P.

Greetings:

Patty's out flying with our AerobaticSource.com Give-Away "Ride Along with Patty" prize winner, John Kovach today. I also know that John was able to attend Dale's birthday party yesterday (quite a treat!), so Patty's been a little busier than usual.

Anyway, if it's any help, Patty and I wrote a story about G-Forces and flying akro.

We're currently editing some video of Patty doing a walk-around her Extra, and in one segment she says that her G meter usually shows about 10+ and off the scale in negative G.

Hope this helps!

Ben

-= VPC OffLine Reader 2.1 =-
Registered to: Ben Chiu
-OLR.PL v1.80-

> Anyway, if it's any help, Patty and I wrote a story about G-Forces and
> flying akro.

Ack! I suppose it would help if I pointed out where to find it.

This story can be found in our Ground School, Aerobatics section.

Ben

-= VPC OffLine Reader 2.1 =-
Registered to: Ben Chiu
-OLR.PL v1.80-

> ...even though Patty, Dale, Dave P, and many others
> could answer much better...

Not to mention our own Ben Chiu! Thanks for directing us to that great article you and Patty wrote on G forces. I read it in Sport Aerobatics, but I didn't know you had it available on line.

Tom P.

Hi Tom:

> Thanks for directing us to that great
> article you and Patty wrote on G forces. I read it in Sport Aerobatics,
> but I didn't know you had it available on line.

We may not be the fastest at it, but we do continuously update the VPC with new content. We tried to post each time we made a new change, but it became pretty cumbersome. The next best thing is to have a look around every few weeks and you'll probably find something new.

Best!

Ben

-= VPC OffLine Reader 2.1 =-
Registered to: Ben Chiu
-OLR.PL v1.80-

>> ...even though Patty, Dale, Dave P, and many others
>> could answer much better...
>
>Not to mention our own Ben Chiu! Thanks for directing us
>to that great article you and Patty wrote on G forces. I
>read it in Sport Aerobatics, but I didn't know you had it
>available on line.
>
>Tom P.

I rarely get involved in discussions on this topic but .... There is much good material in Sport Aerobatics magazine. (I was unaware of the online Ground School here - it deserves to be publicised more).

A few of us in Australia have been active in trying to get our local draft Advisory Circular AC 91.075(0) on track. See it at
http://www.casa.gov.au/avreg/newrules/casr/091.htm
It was derived from the USA AC which I believe to be way outdated. AC91-48, from memory at
http://av-info.faa.gov/dst/ACreference/090-099.htm

My friend, Hilton's comment on this subject was posted a couple of years ago - its copied below for info. (Hilton is a medical doctor and former member of the Australian aerobatic team)

Also, this link to a USN powerpoint slideshow is about the latest military word on the subject and seems to be closer to Hilton's view than earlier work.
http://www.nomi.med.navy.mil/NAMI/GTIP.PPT
If you don't have Powerpoint take a peek at Google's html version at
http://216.239.51.100/search?q=cache:yj3mN-XnBHoC:www.nomi.med.navy.mil/NAMI/GTI\
P.PPT+g+TOLERANCE&hl=en&ie=UTF-8
or download Microsoft's free Powerpoint Viewer at
http://office.microsoft.com/downloads/2000/Ppview97.aspx

One of our local universities is undertaking some research on this subject - a "Survey of G-induced visual
and cognitive disturbances in pilots of high-performance aircraft". Australian Aerobatic pilots were requested to take the time to complete the survey. I must check with them and see how they're going.
http://www.flightmed.com.au/
Go to the What's New page then research project.

Finally, I see that Patty has neatly avoided part of the original question.
' it's not very difficult to stay "conscious" '

I believe that we all do as Hilton says, for positive g manoeuvres. For negative g, just try and relax - but watch out for a sudden change to positive g.

Regards,
Dave Pilkington
__________________

From: "Enid Selvey" <enids@ozemail.com.au>
Date: Mon Jan 31, 2000 10:17 pm
Subject: G-loc cont.

David,

I am as supportive of CASA going the same way as the FAA as the next man and more so than most with regard to the Experimental Category.

But I won’t support CASA when their advice about +G forces is so obviously wrong! The draft A/C on aerobatics was written, I was told, by laymen. By that I understand that the authors were neither aerobatic pilots nor doctors. This is to me very alarming and absurd and should be so to every pilot in Australia.

The advice given to counter the effects of +G may well be the cause of G-LOC accidents and I urge all pilots in Australia to have none of it.

The correct advice is to take up endurance training and when under G stress contract the lower limb and abdominal muscles and BREATHE AS NORMALLY AS POSSIBLE. DO NOT DO THE VALSALVA MANOEUVRE, THE M MANOEUVRE OR ANY OTHER MANOEUVRE BY WHAT EVER NAME WITH THE EXCEPTION OF THE S MANOEUVRE WHICH CONSISTS OF A RAPID DEEP INHALATION AND A NORMAL EXHALATION IF A-LOC IS EXPERIENCED.

You will notice that this advice is the direct opposite to that given under "conventional wisdom". Conventional wisdom is not synonymous with correct wisdom.

A-LOC is the latest, it stands for almost G-LOC! It is the experience of feeling slightly off as if the world has become unreal, everything slightly out of focus. This feeling is followed by black out if the stick forces are not relieved or the S Manoeuvre is not done.

Regards,

Hilton

>Hi, this is my first post and I'm hoping Patty could
>answer a question I've been wanting to ask for some time.
>
>As I understand, you don't wear a G suit for your
>performances as someone flying a military Jet would. I
>was wondering what kind of G's you pull (max G) and at
>what duration in a typical routine. I was also hoping you
>could tell me what exercises you do to strengthen those
>muscles... and if it's possible to describe in writing,
>what muscles to flex and how during sustained Gs.
>
>Ryan

Dear Ryan

I can see my compadres have helped me answer you, as I've been on the road - airshows, flying jets, taking care of business!

Regarding G's, you've had some excellent answers that I will just add too. You are right, small airplane, non-jet aerobatic pilots do not wear G-suits. First of all, our airplanes are not set up for a G-suit which requires compressed air to make it work. Second, the type of G's we pull in say, an Extra or a Sukhoi, is very quick and not the sustained type of G that a military pilot pulls. In addition, we do negative or outside G's where the blood rushes into your head, and a G suit would do nothing to help with that. So there are a lot of reasons we don't wear G' suits.

I normally pull about l0 G's in a normal airsjow routine, and probably about 6 - 7 negative G's. The G's are not sustained and while they take a lot of physical conditioning (and you can get this by flying a lot), they are not sustained and so it's not very difficult to stay "conscious" or "awake" during the maneuvers..unlike in a military jet where you can sustain say, a 9 G turn, for 2 minutes! Duration, not the amount of G's, is harder on the pilot.

I hope this answers your question.

Thanks for coming to AerobaticSource.com!

Patty

Most of the fighter pilots i have known spend alot of time in the wieght room working on thier legs and abdomen.They say by flexing the leg muscles it reduces blood flow to the lower extremeties.Thats the name of the game when trying to prevent blackout.They also squeeze the abdomen muscles which helps .

I referred to AC 91-48 above, however, thats Acrobatics-Precision Flying with a Purpose. The one I meant to refer to was AC 91-61 A Hazard in Aerobatics: Effects of G-Forces of Pilots. Have a look in the context of the comments above.

http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/MainFrame?OpenFrameSet

Regards,
Dave Pilkington

Ryan, The reason G-suits are not used by aerobatic pilots is because they are too bulky. Aerobatic cockpits are smaller than general aviation cockpits, in other words...they take up too much space, and because most aerobatic pilots are in better physical shape than "Fighter-Jocks" they don't need them anyway. To be able to withstand high G-loads you need to have strong abdominal muscles, by tightening those muscles at the onset of high G-loads you will force the blood by up to the brain. Do crunches and sit-ups to get in shape. DRAGON13

Dragon

It's nice that you think akro pilots are in better shape than "fighter jocks" but that's not necessarily the case! The real answer is that in snall aerobatic airplanes the G's are not sustained. In addition, we do "negative" or "outside" G's for which tolerance wouldn't be helped with any type of G suit. It takes practicing and conditioning in the cockpit to stay in shape for strenuous small-airplane G's.

Best,
Patty