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07-07-2012, 05:44 PM
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Join Date: Jan 2005
Location: Twin Cities, MN
Posts: 1,565
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Quote:
Originally Posted by mike in phx
And to all the guys out there i have read about vne and flutter til i turned blue
I do thank you for your concern
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That's great that you've read about it, but what have you done about it? Any changes to better accommodate the high speed? Did you perform a flutter analysis of the airframe? At what speed do you expect flutter to be an issue?
Your turbo mods are certainly very impressive, but without the above it really just seems like more TLAR engineering.
__________________
Brad Benson, Maplewood MN.
RV-6A N164BL, Flying since Nov 2012!
If you're not making mistakes, you're probably not making anything
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07-08-2012, 09:15 AM
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Join Date: Apr 2007
Location: phx
Posts: 61
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Quote:
Originally Posted by ChiefPilot
but without the above it really just seems like more TLAR engineering.
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Wauw thanks for telling me off. Is this experimental category or more mental if it wasnt for tlar engineering nobody would be flying at all. Did The wright brothers get it spot on the first time
It has taken me 1 1/2 years testing to get to the point where i was happy with the system to go to alt and test it. I try to do things as safe as posible so i take it in small increments to get to where the limits are i have had some very smart peoble calculate and advise me on the hole flutter isue and they are very smart. what you have seen here is my limit based on facts, calculations and good advice. I know that there are guys out there that are smarter and has more money than me. This is the second time you have commented on this tread about vne i still wounder if you assume that its all just seat of the pants cowboy style all out flying and that i dont know what this is all about .
I was hoping this was a forum where instead of telling peoble that there hard work and sweat does not mean anything unless you dont experiment.
Instead peoble would appreciate the fact that some one is taking it to a new level. And sharing the results. If you comment again please offer a flutter analysis of the airframe so peoble can se facts. Its so easy to be a nay sayer or to be negative.
The speeds you se here are a max for me at the altitudes i was at. The system can handle this anything above this temperture are the biggest concern.
The system is is built to help out where you are at high alt and need a litle more power to get out of truble and to cruise at higher speeds at alt and compared to fuel burn versus speed the penalty to go 15 kts faster is huge so flying at my max is not for me but i need to know what its capable of.
I would like to be able to share all this in the future with out the negative remarks and again thanks to DR for this board so its possible to share.
If nobody was negative and i just recived it like that i do appologise.
__________________
Mike Poulsen
Phoenix
RV 6 TURBO
N 694 MP
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07-08-2012, 10:36 AM
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VAF Moderator / Line Boy
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Join Date: Jan 2005
Location: Dayton, NV
Posts: 12,256
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Quote:
Originally Posted by mike in phx
I was hoping this was a forum where instead of telling peoble that there hard work and sweat does not mean anything unless you dont experiment.
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Mike, I think that you'll find that this board has a wide variety of people with a huge depth of backgrounds - from aviation newbie to Experimental Test Pilots. We've got guys with advanced degrees in aeronautical engineering,and folks who just like to tinker. And we've got lots and lots of folks that come here just to learn more all the time. Everyone is welcome, so long as they remain civil.
The posts that caution you about Flutter and flying the airframes well above the tested and/or analyzed flutter speeds are cautioning you, not chewing you out. they are also cautioning those with far less experience than you obviously have not to just ignore limits without carefully examining why they are set. You might very well have done structured flutter testing out to the speeds that you are now seeing with your extra horsepower, and that's great - but without presenting that, you risk others without such rigor and experience from just figuring that you are winging it. Van and his engineers have commented numerous times about the need for caution above the factory sped limits with the airplanes because that is what they were designed and tested for. Folks are interested if you have done work beyond that that could enlarge the knowledge base of the entire RV Community. That is part of the experimental part of this activity - doing the rigorous work that helps us all advance.
This approach is not negative - it is cautionary - and it shows concern for the community. I frequently post on trying something new and get comments from from folks that ask "have you considered....?" I take them in the spirit intended, and use those questions to examine my own work to see if I am operating within a good boundary of common sense and reasonable risk.
Experimenting is not just pushing boundaries - it is about pushing them in ways that acknowledge the risks and works to overcome them.
__________________
Paul F. Dye
Editor at Large - KITPLANES Magazine
RV-8 - N188PD - "Valkyrie"
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
A&P, EAA Tech Counselor/Flight Advisor
Dayton Valley Airpark (A34)
http://Ironflight.com
Last edited by Ironflight : 07-09-2012 at 09:19 AM.
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07-09-2012, 09:07 AM
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Join Date: Jan 2005
Location: TX32
Posts: 1,891
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On the lighter side...
Guys,
I am enjoying all this engineering speak and experimentation, but as my 8th grade English teacher Mrs. B used to say "you guys need to check your spelling"
Spell check is a wonderful thing...
Fight's on!
Smokey
PS: BTW, having written the RV VNE article, experimentation and going where no man has gone before is noteworthy. However, it is a consideration, trust me.
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07-09-2012, 10:10 AM
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Join Date: Apr 2007
Location: phx
Posts: 61
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Quote:
Originally Posted by smokyray
Guys,
I am enjoying all this engineering speak and experimentation, but as my 8th grade English teacher Mrs. B used to say "you guys need to check your spelling"
Spell check is a wonderful thing...
Fight's on!
Smokey
PS: BTW, having written the RV VNE article, experimentation and going where no man has gone before is noteworthy. However, it is a consideration, trust me.
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Thanks ray
Danish being my native tunge i dont always spell that well in english but i se you get the point
And the article I know it by heart very well written
__________________
Mike Poulsen
Phoenix
RV 6 TURBO
N 694 MP
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07-09-2012, 10:56 AM
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Join Date: Jan 2005
Location: Louisville, Ga
Posts: 7,840
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Don't stop.
Mike there are quite a few gearheads like you and me on here as well. I've built two 427 Cobra kits and owned a Pantera and we enjoy reading about your turbo experience.
I enjoy those as well as the Rockets and Super -8's with IO-540's in them, so keep your articles coming.
Thanks,
__________________
Pierre Smith
RV-10, 510 TT
RV6A (Sojourner) 180 HP, Catto 3 Bl (502Hrs), gone...and already missed
Air Tractor AT 502B PT 6-15 Sold
Air Tractor 402 PT-6-20 Sold
EAA Flight Advisor/CFI/Tech Counselor
Louisville, Ga
It's never skill or craftsmanship that completes airplanes, it's the will to do so,
Patrick Kenny, EAA 275132
Dues gladly paid!
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07-09-2012, 10:43 PM
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Join Date: May 2011
Location: Pleasant Hill, CA
Posts: 32
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I have a question on the flutter issue. Looking at the screen shots it appears that the IAS is 150 kts or so. The TAS is 220 or something like that. Since VNE and flutter are related to IAS and not TAS I don't see the concern with flutter here as the IAS is below VNE. Am I missing something?
Nigel
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07-09-2012, 11:04 PM
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Join Date: Feb 2007
Location: San Diego, CA
Posts: 1,670
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Yes, you are missing something. A lot of us missed it along the way, until an article was posted on Vans Aircraft web site. Click on THIS to read the informative article. It is a link to a .pdf that will download. It turns out that flutter is directly related to True Air Speed (TAS), not IAS as we all used to think. Hence the concern in the thread.
Quote:
Originally Posted by N111BN
I have a question on the flutter issue. Looking at the screen shots it appears that the IAS is 150 kts or so. The TAS is 220 or something like that. Since VNE and flutter are related to IAS and not TAS I don't see the concern with flutter here as the IAS is below VNE. Am I missing something?
Nigel
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__________________
Pete Hunt, [San Diego] VAF #1069
RV-6, RV-6A, T-6G
ATP, CFII, A&P
2020 Donation+, Gladly Sent
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07-10-2012, 05:21 AM
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Join Date: Jun 2005
Location: Locust, NC
Posts: 440
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true vs indicated
Okay, I understand the need to treat use the true airspeed Vne limitation to avoid flutter. What I don't understand is why I have never ever seen this mentioned in any magazine or flight training material regarding certified airplanes. Piper, Beech and Mooney (older, non-turbo) seem to treat Vne as an indicated airspeed limitation.
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Dave
M20C
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07-10-2012, 07:11 AM
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Join Date: Jan 2005
Location: Broomfield, CO
Posts: 639
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Quote:
Originally Posted by dlloyd3
What I don't understand is why I have never ever seen this mentioned in any magazine or flight training material regarding certified airplanes. Piper, Beech and Mooney (older, non-turbo) seem to treat Vne as an indicated airspeed limitation.
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That, too, is addressed in the linked article above. Some airplanes have a barber pole on the airspeed indicator that points to Vne and that pole decreases with altitude to account for lower indicated/higher true. The Navy T-34C is like this. The normal Vne is 280KIAS and that is where the barber pole points while sitting on the ground. But as you climb towards 25,000ft, that pole begins to decrease. I believe it gets down to around 250KIAS at 25K'. Hope this helps.
__________________
RV-7 Flying since 2004
1,100 hrs+
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