g-loads was Re: [F3F] DS record burns to 232mph - RC Groups
Oct 29, 2003, 04:01 AM
Bill Johns
Bill Johns
Guest

# [RCSE] g-loads was Re: [F3F] DS record burns to 232mph

At 05:26 PM 10/28/2003, rsiegel wrote:
>Can a full scale airplane *survive* DS?

Probably not.

> What are the g-loads at these
>speeds and in this flight profile?

Some time ago there was a video of JW doing some DS'ing, one of the first
DS'ing videos out. The question of g-loading came up then, too. Knowing
the plane he was flying at the time, it had about a 120 inch span, I played
and replayed the sequence and got an average "loop"time. Know the span, I
measured the extremes of the circle the plane was flying and managed to get
a diameter. It was all pretty straight forward. There is a standard
formula some place for figuring out g-loads. It worked out to about 20-22
g's. I think at that time the planes were flying about 150 mph. At 230
mph..... =:-o

No, I doubt the full scale plane could survive DS'ing, and if it could, the
pilot could not. What are full scale sailplanes stressed for
anyway?? Anyone know what an F-15 is stressed for? I suspect g-loads are
limited by the pilots. So what can a superbly conditioned human take for
15 seconds and still function? 8-10 g's?

Cheers,

Bill

--

Bill Johns
Pullman, WA
USA

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Oct 29, 2003, 04:01 AM
Guest

# Re: [RCSE] g-loads was Re: [F3F] DS record burns to 232mph

At 06:19 PM 10/28/03 -0800, Bill Johns wrote:
>At 05:26 PM 10/28/2003, rsiegel wrote:

>No, I doubt the full scale plane could survive DS'ing, and if it could, the
>pilot could not. What are full scale sailplanes stressed for
>anyway?? Anyone know what an F-15 is stressed for? I suspect g-loads are
>limited by the pilots. So what can a superbly conditioned human take for
>15 seconds and still function? 8-10 g's?\

I think the F-15 is stressed for around 7.5g's. Somewhat newer composite
planes like the F-16 are stressed for 9g or so, but I thing 9 is about the
human limit for sustained g's. Competition aerobatic pilots will pull 10
or 12 g's, and do it without g-suits, but only for very short periods of time.

>
>Cheers,
>
>Bill
>
>--
>
>Bill Johns
>Pullman, WA
>USA
>
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Oct 29, 2003, 04:01 AM
James V. Bacus
James V. Bacus
Guest

# Re: [RCSE] g-loads was Re: [F3F] DS record burns to 232mph

At 08:19 PM 10/28/2003, Bill Johns wrote:
>Some time ago there was a video of JW doing some DS'ing, one of the first
>DS'ing videos out. The question of g-loading came up then, too. Knowing
>the plane he was flying at the time, it had about a 120 inch span, I
>played and replayed the sequence and got an average "loop"time. Know the
>span, I measured the extremes of the circle the plane was flying and
>managed to get a diameter. It was all pretty straight forward. There is
>a standard formula some place for figuring out g-loads. It worked out to
>about 20-22 g's. I think at that time the planes were flying about 150
>mph. At 230 mph..... =:-o

Someone could put one of these in a DS model and we could measure it... 8-)
http://www.g-labs.com/

Jim
Downers Grove, IL
Member of the Chicago SOAR club, AMA 592537 LSF 7560 Level IV
ICQ: 6997780 AIM: InventorJim R/C Soaring blog at www.jimbacus.net

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Oct 29, 2003, 04:01 AM
James V. Bacus
James V. Bacus
Guest

# Re: [RCSE] g-loads was Re: [F3F] DS record burns to 232mph

>Someone could put one of these in a DS model and we could measure it... 8-)
>http://www.g-labs.com/

loads on Capn' Jack's ICON when he does his typical power dork landings. 8-)

Jim
Downers Grove, IL
Member of the Chicago SOAR club, AMA 592537 LSF 7560 Level IV
ICQ: 6997780 AIM: InventorJim R/C Soaring blog at www.jimbacus.net

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Oct 29, 2003, 04:01 AM
GordySoar@aol.com
GordySoar@aol.com
Guest

# Re: [RCSE] g-loads was Re: [F3F] DS record burns to 232mph

There is a standard formula some place for figuring out g-loads.

Or you can simply buy a G-spot g-load recorder. Created by DS'rs for DS'rs.
Gordy

Oct 29, 2003, 04:01 AM
Marc Gellart
Marc Gellart
Guest

# Re: [RCSE] g-loads was Re: [F3F] DS record burns to 232mph

F-15's and F-16's were deigned about the same time by a group of AF Officers
spearheading the projects known as the Fighter Mafia. They both can take
sustained 9 g's but the guys flying them had better be in shape and thinking
out ahead of their flying so they can prepare their breathing and body
muscle tone to help sustain their conscienceness. You are probably seeing
the final generation of high g fighters with live pilots as they will
outstrip pilots abilities to live through the capabilities of the ships.
Paul Trist told us at the SSA convention that a few folks have tried DS with
a sailplane that escapes me but they were going slow and nothing like what a
230 mph model is doing.

Marc

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Oct 29, 2003, 04:01 AM
Richard Border
Richard Border
Guest

# Re: [RCSE] g-loads was Re: [F3F] DS record burns to 232mph

So what can a superbly conditioned human take for
> 15 seconds and still function? 8-10 g's?

Bob Champine, a Level V, did 18g in a centrafuge, he held the record for a
short period of time, then someone did 20g. His daughter did a website on
him, he flew the X-1, D-558 and more.
Rich Border

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Oct 29, 2003, 04:01 AM
JDavies456@aol.com
JDavies456@aol.com
Guest

# Re: [RCSE] g-loads was Re: [F3F] DS record burns to 232mph

G Loads based on a turn where the stick is not abruptly moved during the
turn.
Angle of bank = G load
40 degrees 1.3 G
60 2.0
80 5.75
90 9.2
SUSTAINED 90 degree bank is not theoretically possible. A long time ago,
in another life, I did this sort of thing for the USAF for a few years. Oddly
enough.. after a while you get to "like" the pull of G's when horsing around.
Between being in great shape, the G suit, breathing O2 and grunting a lot it's
amazing what the body will endure. High G turns are almost always of BRIEF
duration.
As far as DSing is concerned; it seems to me that the in-flight failures are
more likely a function of SPEED vs G loads. The F-16, I'm told, will
routinely handle 9 Gs but there is surely an airspeed redline where things start
coming apart. ~JD~ San Diego
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Oct 29, 2003, 07:01 PM
strotherbj@comcast.net
strotherbj@comcast.net
Guest

# Re: [RCSE] g-loads was Re: [F3F] DS record burns to 232mph

Thats waay COLD..
with NO GRACE !!
8-)
J

--
Jack Strother
LSF President LSF 2948
Granger, IN Level IV
>
> >Someone could put one of these in a DS model and we could measure it... 8-)
> >http://www.g-labs.com/

>
> loads on Capn' Jack's ICON when he does his typical power dork landings. 8-)
>
>
> Jim
> Downers Grove, IL
> Member of the Chicago SOAR club, AMA 592537 LSF 7560 Level IV
> ICQ: 6997780 AIM: InventorJim R/C Soaring blog at www.jimbacus.net
>
> RCSE-List facilities provided by Model Airplane News. Send "subscribe" and
> "unsubscribe" requests to soaring-request@airage.com. Please note that
> subscribe and unsubscribe messages must be sent in text only format with MIME
> turned off.

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