Today's Message Index:
----------------------
1. 08:50 PM - Re: Dive Tests (teamgrumman@aol.com)
2. 09:45 PM - Re: Dive Tests (Gil Alexander)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
Remember how when we were in grade school and the teacher whispered somethin
g into one person's ear and then that person whispered it into another perso
n's ear and then the last kid was asked to repeat what was said? =C2-
Where did True Airspeed come from?
Vne has nothing to do with TAS. =C2-
The FAA wants a dive test to Vne + 20%. =C2-We've petitioned for Vne + 10%
.
-----Original Message-----
From: Gil Alexander <gilalex@earthlink.net>
Sent: Fri, 4 Jan 2008 7:35 am
Subject: Re: TeamGrumman-List: Dive Tests
Ned... the FAA might only use IAS for testing, but they can
change Vne with altitude (essentially correcting it back to
TAS).
The FAA paperwork to certify my Mini-Nimbus sailplane shows this...
Page 4 of the pilots manual supplement has a Vne correction for
altitude...
http://www.schempp-hirth.com/fileadmin/tmdocs/328-6-1427.pdf
The correction reduces the IAS for Vne from 135 kts to 120 kts at 19,700
ft
I never bothered certifying my glider (only one in the US did, and it's a
rental) since my operating limitations are so lax, Experimental,
Exhibition and Racing is better...
gil A
At 07:50 AM 1/4/2008, you wrote:
--> TeamGrumman-List message
posted by: "923te" <923te@cox.net>
Gary,
Will an FAA representative be in teh plane with you when you dive it 240
mph
Are you concerned a little about it? We don't want to lose you over some
insidious FAA CYA program.
Here are some comments Fred Kokaska made to me about his dive
testing:
".....
In CFR Part 23 certification the term TAS is never defined, recognized or
addressed.=C2- They have V speed numbers for everything but all
testing, structural flight testing, climb/cooling flight testing are all
related to IAS.
They will require a correction chart be developed for installation error
of the pitot tube so that test result data is really based on CAS after
observed temp and installation errors are accounted for.
A manufacturer of a new design must define and demonstrate (Vd) (Dive
speed as part of the overall envelope) After demonstrating a dive at Vd
the FAA established Vne (AA5B 174 KCAS) as 90% of demonstrated Vd (FAA
takes away 10% as a safety factor) . I went through the Vne part of
certification at 100% of Vne for an AA5B (174 KIAS), There were two Part
23 objectives in this flight test (flown by FAA test pilot) of verifying
the prop does not overspeed (above 2700 RPM) at Vne. This was easy as the
back stop in the CS prop would probably allow 220 KIAS before it ran out
of pitch. On a fixed pitch prop this can be a show stopper and require
reducing Vne to prevent the overspeed. The other was pitch and roll
control and airframe vibration. The test pilot started at 10 K feet and
pushed over at full power to establish 174 KIAS, did some 30 degree left
and right rolling maneuvers. He commented (and I looked out the right
side) on the fact the ailerons were both about 2 inches above the normal
even with the flap position in level flight from airloads. While this
looks spooky, he noticed no binding or control input problems that he did
not like.
So, to answer your question .... I have never seen any reference to the
term "TAS" in any certification requirement.
Sombody ought to follow up with the FAA to get the right A/S marking in
the 2400 Lb Cheetahs that have the AA5B spar installed. They approved
AA5B airspeed markings for the spar upgrade in Peter Otten's IO-360 STC
so you have an approved example.
Cheers=C2-=C2- Fred Kokaska"
Stay safe,
Ned
For-what-it's-worth: B The FAA
is making me do carb heat rise tests on my new
cowling. B My cowling has in no way affected the source, path, or
operation of
the carb heat. B Their argument: B Since I "MAY" have changed
the air pressure
in the lower cowling, I "MAY" have changed the operation of
carb heat. B SO .
. . B I tested a stock Tiger. B It doesn't pass the test. B I tested a
stock
Tiger with a Power Flow. B It doesn't pass the test either (by 4
degrees).
B Testing on my new cowling starts as soon as it stops raining.
I also have to dive the plane to 240 mph. B But, that's a different
story. B
TeamGrumman-List Email Forum -
http://www.matronics.com/Navigator?TeamGrumman-List
;=C2-=C2-
- MATRONICS WEB FORUMS -
http://forums.matronics.com
;
- List Contribution Web Site -
;=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-
=C2-=C2-=C2-=C2-=C2-
-Matt Dralle, List Admin.
http://www.matronics.com/contribution
________________________________________________________________________
aol.com
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
Gary... I have an old, but very interesting FAA
document "Basic Glider Criteria", a 140 page book.
It's one where the FAA slipped up and published
all of the design (aero/structure) and testing criteria for a sailplane....
Enough data to actually design and certify a glider...
It details how to meet the older CAR Part 5
standards.... Were our Grummans designed to this standard too?
They have a Vd as Design speed, and set Vne as 0.9*Vd.
The flight testing section (yes, they defined
that too...) under flutter testing describes how
to do the tests, and says testing only needs to be done to the Vd speed.
This is essentially the +10% you are asking for... well actually 11.1%
Perhaps you can use this in your justification..... gil A
At 09:44 PM 1/7/2008, you wrote:
>Remember how when we were in grade school and
>the teacher whispered something into one
>person's ear and then that person whispered it
>into another person's ear and then the last kid
>was asked to repeat what was said? =C2
>
>Where did True Airspeed come from?
>
>Vne has nothing to do with TAS. =C2
>
>The FAA wants a dive test to Vne + 20%. =C2 We've petitioned for Vne + 10%.
>
>
>-----Original Message-----
>From: Gil Alexander <gilalex@earthlink.net>
>To: teamgrumman-list@matronics.com
>Sent: Fri, 4 Jan 2008 7:35 am
>Subject: Re: TeamGrumman-List: Dive Tests
>
>Ned... the FAA might only use IAS for testing,
>but they can change Vne with altitude (essentially correcting it back to
TAS).
>
>The FAA paperwork to certify my Mini-Nimbus sailplane shows this...
>
>Page 4 of the pilots manual supplement has a Vne correction for altitude...
>
><http://www.schempp-hirth.com/fileadmin/tmdocs/328-6-1427.pdf>http://www.sc
hempp-hirth.com/fileadmin/tmdocs/328-6-1427.pdf
>
>The correction reduces the IAS for Vne from 135 kts to 120 kts at 19,700 ft
>
>I never bothered certifying my glider (only one
>in the US did, and it's a rental) since my
>operating limitations are so lax, Experimental,
>Exhibition and Racing is better...
>
>gil A
>
>
>At 07:50 AM 1/4/2008, you wrote:
>><<mailto:923te@cox.net>923te@cox.net>
>>
>>Gary,
>>
>>Will an FAA representative be in teh plane with you when you dive it 240
mph
>>Are you concerned a little about it? We don't
>>want to lose you over some insidious FAA CYA program.
>>
>>Here are some comments Fred Kokaska made to me about his dive testing:
>>".....
>>In CFR Part 23 certification the term TAS is
>>never defined, recognized or addressed.=C2 They
>>have V speed numbers for everything but all
>>testing, structural flight testing,
>>climb/cooling flight testing are all related to IAS.
>>They will require a correction chart be
>>developed for installation error of the pitot
>>tube so that test result data is really based
>>on CAS after observed temp and installation errors are accounted for.
>>A manufacturer of a new design must define and
>>demonstrate (Vd) (Dive speed as part of the
>>overall envelope) After demonstrating a dive at
>>Vd the FAA established Vne (AA5B 174 KCAS) as
>>90% of demonstrated Vd (FAA takes away 10% as a
>>safety factor) . I went through the Vne part of
>>certification at 100% of Vne for an AA5B (174
>>KIAS), There were two Part 23 objectives in
>>this flight test (flown by FAA test pilot) of
>>verifying the prop does not overspeed (above
>>2700 RPM) at Vne. This was easy as the back
>>stop in the CS prop would probably allow 220
>>KIAS before it ran out of pitch. On a fixed
>>pitch prop this can be a show stopper and
>>require reducing Vne to prevent the overspeed.
>>The other was pitch and roll control and
>>airframe vibration. The test pilot started at
>>10 K feet and pushed over at full power to
>>establish 174 KIAS, did some 30 degree left and
>>right rolling maneuvers. He commented (and I
>>looked out the right side) on the fact the
>>ailerons were both about 2 inches above the
>>normal even with the flap position in level
>>flight from airloads. While this looks spooky,
>>he noticed no binding or control input problems that he did not like.
>>So, to answer your question .... I have never
>>seen any reference to the term "TAS" in any certification requirement.
>>Sombody ought to follow up with the FAA to get
>>the right A/S marking in the 2400 Lb Cheetahs
>>that have the AA5B spar installed. They
>>approved AA5B airspeed markings for the spar
>>upgrade in Peter Otten's IO-360 STC so you have an approved example.
>>
>>Cheers=C2 =C2 Fred Kokaska"
>>
>>Stay safe,
>>
>>Ned
>>
>>
>>>For-what-it's-worth: B The FAA is making me do
>>>carb heat rise tests on my new
>>>cowling. B My cowling has in no way affected
>>>the source, path, or operation of
>>>the carb heat. B Their argument: B Since I
>>>"MAY" have changed the air pressure
>>>in the lower cowling, I "MAY" have changed the
>>>operation of carb heat. B SO .
>>>. . B I tested a stock Tiger. B It doesn't pass the test. B I tested a
stock
>>>Tiger with a Power Flow. B It doesn't pass the test either (by 4
degrees).
>>>B Testing on my new cowling starts as soon as it stops raining.
>>>
>>>
>>>
>>>
>>>I also have to dive the plane to 240 mph. B But, that's a different
story. B
>>>
>>
>>
>>==========
>>TeamGrumman-List Email Forum -
>><http://www.matronics.com/Navigator?TeamGrumman-List>http://www.matronics.
com/Navigator?TeamGrumman-List
>>==========
>>;=C2 =C2 - MATRONICS WEB FORUMS -
>><http://forums.matronics.com/>http://forums.matronics.com
>>==========
>>; - List Contribution Web Site -
>>;=C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2 =C2
-Matt Dralle, List Admin.
>><http://www.matronics.com/contribution>http://www.matronics.com/contributi
on
>>==========
>>
>
>
>or?TeamGrumman-List">http://www.matronics.com/Navigator?TeamGrumman-List
>p://forums.matronics.com
>ution">http://www.matronics.com/contribution
>
>
>----------
>More new features than ever. Check out the new
><http://o.aolcdn.com/cdn.webmail.aol.com/mailtour/aol/en-us/text.htm?ncid
=aolcmp00050000000003>AOL
>Mail!
>
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|