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jjessen
Joined: 22 Apr 2006
Posts: 285
Location: OR
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 Posted: Tue Mar 27, 2007 8:30 am Post subject: Flutter at altitude |
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Most of you are probably watching the TAS / IAS flutter thread on the generic RV Matronics site. Some of you have already weighed in. My question for RV-10 flyers, has anyone come up with a "at altitude IAS speed limitation" chart? Is anyone thinking about such? In essence, IAS Vne for 10k, 12k, 14k, 16k, 18k?
John (how in the heck did you guys rivet the spar to the trim tabs) Jessen
#40328
[quote][b]
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Tim Olson
Joined: 25 Jan 2007
Posts: 2882
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| Posted: Tue Mar 27, 2007 9:07 am Post subject: Flutter at altitude |
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The first question probably isn't practical for all but the
most anal of people....but many of the EFIS systems read
TAS anyway, so it's a non-issue then.
As for the trim tabs.....rivet the hinge alone perhaps, then
pin it.
Tim
do not archive
John Jessen wrote:
| Quote: | Most of you are probably watching the TAS / IAS flutter thread on the
generic RV Matronics site. Some of you have already weighed in. My
question for RV-10 flyers, has anyone come up with a "at altitude IAS
speed limitation" chart? Is anyone thinking about such? In essence,
IAS Vne for 10k, 12k, 14k, 16k, 18k?
John (how in the heck did you guys rivet the spar to the trim tabs) Jessen
#40328
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glastar(at)gmx.net
Guest
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| Posted: Tue Mar 27, 2007 9:21 am Post subject: Flutter at altitude |
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Hello John,
we do some test flights here in Switzerland and have also to approach Vne for that.
Following is our test sheet for that:
Altitude
(ft) Vne
(1) Faktor
(2) 4000
0.9419 6000 0.9142 8000 0.8865 10000 0.8593 12000 0.8325 14000 0.8061 16000 0.7802
and your Vne calculates Vne on SL (1) * by Factor (2)
John Jessen wrote: [quote] DIV { MARGIN: 0px } Most of you are probably watching the TAS / IAS flutter thread on the generic RV Matronics site. Some of you have already weighed in. My question for RV-10 flyers, has anyone come up with a "at altitude IAS speed limitation" chart? Is anyone thinking about such? In essence, IAS Vne for 10k, 12k, 14k, 16k, 18k?
John (how in the heck did you guys rivet the spar to the trim tabs) Jessen
#40328
[b]
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AV8ORJWC
Joined: 13 Jul 2006
Posts: 1149
Location: Aurora, Oregon "Home of VANS"
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| Posted: Tue Mar 27, 2007 11:22 am Post subject: Flutter at altitude |
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I waste too much time now on eight other dissimilar sites, but I can surmise the discussion must be interesting.
Ken Scott rehashed his ole RVator article to get into Kitplanes as a contributing author. Few readers have noticed that Ken and VANS is deeply concerned (more than any other kit company) on Flutter. With 5,000 flying… they should know. Let’s see 71 out of 5000, that is less than 2% and our RV-10s are considerably heavier, more powerful with more useful load. I conclude they are a different cat all together. Is Ken warning us of a design flaw(s)? Could it be weight reduction issues based on a reduced rib count, thin skin or flimsy design? I think not. but Chicken Little sure has me looking to the sky for falling parts. Most RV-10 Builders would rather give up an arm than stop drinking the Kool aid and research such a possibility.
I am pursuing with several Aeronautical Engineers who write regular stories, what things can be improved on the RV-10 to reduce the risk of Flutter and allow greater actual (IAS at the service ceiling) airspeeds like many other kit built aircraft. I still don’t know how we did it in WWII with fabric covered control surfaces. I understand clearly that the Lurkers are now scurrying to VAN to report such blasphemy but I was reflecting that just this morning – In the last three years, little has been done to improve the written instructions, address the known issues brought by this group and any indication that the existing product could ever be improved upon. I think VAN needs a panel of builders who have built and now fly the 10 to guide such an improvement process. Re-reading about flutter just get’s my heart jumping like a butterfly.
All of the benefits I have seen have been through open minds, open discussion, sharing of build techniques and those willing to stick their necks out to improve the final quality of a Great kit – the RV-10. How many have recently viewed Dan’s site for total accidents and studied the NTSB reports on those that were fatals? It is a sick thought… just like Flutter and just a valuable.
I for one declare the Kitplane article – clear propaganda and challenge the other kit component manufacturers sitting on VANS 51% Rewrite Committee to fess up they are placing their owners at risk with speeds greater than our beloved RV-10s. They don’t have 5,000 flying, they don’t discuss flutter and they should as well. With the understanding can come an increase in design improvement with speed, altitude and economy to boot. It sure got attention though.
Could I have another glass, please? I’ll go back to reading the instructions or taking a long nap now.
John C.
PS – John, no one has placed a price on that cheap Beech of Tom’s, so if you are interested, I have a 50% interest in a Beech A-36 to get you through the build process at Lenhardt’s Airpark.
From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of John Jessen
Sent: Tuesday, March 27, 2007 9:28 AM
To: rv10-list(at)matronics.com
Subject: Flutter at altitude
Most of you are probably watching the TAS / IAS flutter thread on the generic RV Matronics site. Some of you have already weighed in. My question for RV-10 flyers, has anyone come up with a "at altitude IAS speed limitation" chart? Is anyone thinking about such? In essence, IAS Vne for 10k, 12k, 14k, 16k, 18k?
John (how in the heck did you guys rivet the spar to the trim tabs) Jessen
#40328 [quote] [b]
| | - The Matronics RV10-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV10-List |
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deutscht(at)rhwhotels.com
Guest
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| Posted: Tue Mar 27, 2007 12:03 pm Post subject: Flutter at altitude |
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Tom’s Bonanza price is $58,000
Tom Deutsch #40545
Office 913 451-1222
Fax 913 451-6493
Cell 913 908-7752
From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of John W. Cox
Sent: Tuesday, March 27, 2007 2:21 PM
To: rv10-list(at)matronics.com
Subject: RE: Flutter at altitude
I waste too much time now on eight other dissimilar sites, but I can surmise the discussion must be interesting.
Ken Scott rehashed his ole RVator article to get into Kitplanes as a contributing author. Few readers have noticed that Ken and VANS is deeply concerned (more than any other kit company) on Flutter. With 5,000 flying… they should know. Let’s see 71 out of 5000, that is less than 2% and our RV-10s are considerably heavier, more powerful with more useful load. I conclude they are a different cat all together. Is Ken warning us of a design flaw(s)? Could it be weight reduction issues based on a reduced rib count, thin skin or flimsy design? I think not. but Chicken Little sure has me looking to the sky for falling parts. Most RV-10 Builders would rather give up an arm than stop drinking the Kool aid and research such a possibility.
I am pursuing with several Aeronautical Engineers who write regular stories, what things can be improved on the RV-10 to reduce the risk of Flutter and allow greater actual (IAS at the service ceiling) airspeeds like many other kit built aircraft. I still don’t know how we did it in WWII with fabric covered control surfaces. I understand clearly that the Lurkers are now scurrying to VAN to report such blasphemy but I was reflecting that just this morning – In the last three years, little has been done to improve the written instructions, address the known issues brought by this group and any indication that the existing product could ever be improved upon. I think VAN needs a panel of builders who have built and now fly the 10 to guide such an improvement process. Re-reading about flutter just get’s my heart jumping like a butterfly.
All of the benefits I have seen have been through open minds, open discussion, sharing of build techniques and those willing to stick their necks out to improve the final quality of a Great kit – the RV-10. How many have recently viewed Dan’s site for total accidents and studied the NTSB reports on those that were fatals? It is a sick thought… just like Flutter and just a valuable.
I for one declare the Kitplane article – clear propaganda and challenge the other kit component manufacturers sitting on VANS 51% Rewrite Committee to fess up they are placing their owners at risk with speeds greater than our beloved RV-10s. They don’t have 5,000 flying, they don’t discuss flutter and they should as well. With the understanding can come an increase in design improvement with speed, altitude and economy to boot. It sure got attention though.
Could I have another glass, please? I’ll go back to reading the instructions or taking a long nap now.
John C.
PS – John, no one has placed a price on that cheap Beech of Tom’s, so if you are interested, I have a 50% interest in a Beech A-36 to get you through the build process at Lenhardt’s Airpark.
From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of John Jessen
Sent: Tuesday, March 27, 2007 9:28 AM
To: rv10-list(at)matronics.com
Subject: Flutter at altitude
Most of you are probably watching the TAS / IAS flutter thread on the generic RV Matronics site. Some of you have already weighed in. My question for RV-10 flyers, has anyone come up with a "at altitude IAS speed limitation" chart? Is anyone thinking about such? In essence, IAS Vne for 10k, 12k, 14k, 16k, 18k?
John (how in the heck did you guys rivet the spar to the trim tabs) Jessen
#40328 012345
[quote][b]
| | - The Matronics RV10-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV10-List |
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james.k.hovis(at)gmail.co
Guest
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| Posted: Wed Mar 28, 2007 8:10 am Post subject: Flutter at altitude |
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John,
I am an aerospace engineer (work for a large midwestern producer of
many types of aircraft that'll remain nameless at this time...) and as
you know I've been lurking and commenting on this issue every once in
a while. Part 23.629 covers flutter for certifying small aircraft. In
that subpart, you have several methods to show compliance, mainly
either flight testing and ground vibration testing or analysis by a
few methods. One is compliance with Engineering Report No. 45 if the
Vd is less than 260 kts. I can't find that report on line to see
what's entailed. Testing and analysis has to show the airframe free of
flutter up to a speed of equal to Vd. Structural stiffness and mass
balance of control surfaces affect flutter limits more than anything.
Looking at the overall design of the RV-10, it is very similar to
other aircraft that have been shown to be free from flutter within
speed ranges similar to RV-10 limits (statistical analysis). Also,
Appendix A of part 23 gives some simplified formulas for compliance on
conventional light aircraft under 6,000#, which the RV-10 definitly
fits within. Speeds to be used for the V-n diagram are given based on
w/s and load factor. A minimum Vd can be calculated as 24 * sqrt(n1
*(w/s)) in kts. This is 199.83 kts and 230 mph plugging in 3.8g for n1
and the Van's gross w/s.
Bottom line is the Feds want you to show that your airframe is free
from flutter up to a certain speed based on w/s and load factor. You
can test for higher speeds if you wish, but a conservative approach is
to keep the speed close to the required minimum.
Kevin Hovis.
On 3/27/07, John W. Cox <johnwcox(at)pacificnw.com> wrote:
| Quote: | I waste too much time now on eight other dissimilar sites, but I can
surmise the discussion must be interesting.
Ken Scott rehashed his ole RVator article to get into Kitplanes as a
contributing author. Few readers have noticed that Ken and VANS is
deeply concerned (more than any other kit company) on Flutter. With
5,000 flying... they should know. Let's see 71 out of 5000, that is
less than 2% and our RV-10s are considerably heavier, more powerful with
more useful load. I conclude they are a different cat all together. Is
Ken warning us of a design flaw(s)? Could it be weight reduction issues
based on a reduced rib count, thin skin or flimsy design? I think not.
but Chicken Little sure has me looking to the sky for falling parts.
Most RV-10 Builders would rather give up an arm than stop drinking the
Kool aid and research such a possibility.
I am pursuing with several Aeronautical Engineers who write regular
stories, what things can be improved on the RV-10 to reduce the risk of
Flutter and allow greater actual (IAS at the service ceiling) airspeeds
like many other kit built aircraft. I still don't know how we did it in
WWII with fabric covered control surfaces. I understand clearly that the
Lurkers are now scurrying to VAN to report such blasphemy but I was
reflecting that just this morning - In the last three years, little has
been done to improve the written instructions, address the known issues
brought by this group and any indication that the existing product could
ever be improved upon. I think VAN needs a panel of builders who have
built and now fly the 10 to guide such an improvement process.
Re-reading about flutter just get's my heart jumping like a butterfly.
All of the benefits I have seen have been through open minds, open
discussion, sharing of build techniques and those willing to stick their
necks out to improve the final quality of a Great kit - the RV-10. How
many have recently viewed Dan's site for total accidents and studied the
NTSB reports on those that were fatals? It is a sick thought... just
like Flutter and just a valuable.
I for one declare the Kitplane article - clear propaganda and challenge
the other kit component manufacturers sitting on VANS 51% Rewrite
Committee to fess up they are placing their owners at risk with speeds
greater than our beloved RV-10s. They don't have 5,000 flying, they
don't discuss flutter and they should as well. With the understanding
can come an increase in design improvement with speed, altitude and
economy to boot. It sure got attention though.
Could I have another glass, please? I'll go back to reading the
instructions or taking a long nap now.
John C.
PS - John, no one has placed a price on that cheap Beech of Tom's, so if
you are interested, I have a 50% interest in a Beech A-36 to get you
through the build process at Lenhardt's Airpark.
________________________________
From: owner-rv10-list-server(at)matronics.com
[mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of John Jessen
Sent: Tuesday, March 27, 2007 9:28 AM
To: rv10-list(at)matronics.com
Subject: Flutter at altitude
Most of you are probably watching the TAS / IAS flutter thread on the
generic RV Matronics site. Some of you have already weighed in. My
question for RV-10 flyers, has anyone come up with a "at altitude IAS
speed limitation" chart? Is anyone thinking about such? In essence,
IAS Vne for 10k, 12k, 14k, 16k, 18k?
John (how in the heck did you guys rivet the spar to the trim tabs)
Jessen
#40328
|
| | - The Matronics RV10-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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Phil White
Joined: 10 Jan 2006
Posts: 45
Location: Downers Grove, IL
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| Posted: Wed Mar 28, 2007 9:07 am Post subject: Flutter at altitude |
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Ran a quick Excel plot of the factors listed by Werner, and produced the
following:
RV-10 VNE speeds
ALT IAS-mph
0 230.0
4 216.6
6 216.5
8 203.9
10 197.6
12 191.5
14 185.4
16 179.4
18 173.7
20 168.1
22 162.8
24 157.6
or print from the attached Excel file.
Phil White #40220 (doors)
| | - The Matronics RV10-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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| Description: |
|
Download |
| Filename: |
RV-10_VNE_IASpds_.xls |
| Filesize: |
15.5 KB |
| Downloaded: |
192 Time(s) |
_________________
RV-10 #40220 in Downers Grove, IL
(airframe done exc. gear fairings) |
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AV8ORJWC
Joined: 13 Jul 2006
Posts: 1149
Location: Aurora, Oregon "Home of VANS"
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| Posted: Wed Mar 28, 2007 9:23 am Post subject: Flutter at altitude |
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Timely and valuable insight - Bravo. A great example of the value of
this list. For those still thinking that control surfaces don't need no
stinking balancing. Contact Kevin for a professional's unbiased
opinion. As an A&P it is always to be done without exception. It's done
after manufacture, its done after paint, its done after a major repair
or alteration. Now to get all of you the simple process as to how to
balance a control surface. Just one of the steps to reduce the risks of
flutter - Balanced control surfaces.
Flaps, Ailerons, Elevator and Rudder.
I don't need 260 knots, but I would love 200 knots at altitude and
appreciate the meat (kernels of useful info) you have offered to go with
the conversation of Flutter - now published twice.
John
--
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flywrights(at)yahoo.com
Guest
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| Posted: Wed Mar 28, 2007 1:54 pm Post subject: Flutter at altitude |
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Sounds like we need to convice all of our EFIS manufacturers to write a software update calculating a "barber pole" for the higher altitude TASs at DA.
Rob Wright
#392
Fuse - need to paint the interior soon - getting hot!
---
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