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jmaynard
Joined: 27 Feb 2008 Posts: 394 Location: Fairmont, MN (FRM)
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Posted: Mon Nov 17, 2008 10:10 am Post subject: All 601XL grounded in Netherlands |
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On Mon, Nov 17, 2008 at 09:58:18AM -0800, Paul Mulwitz wrote:
Quote: | His observation that his cables were loose suggests to me that we should
all keep a close watch on those cables.
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Indeed. Cable tension checks are now part of my 50-hour routine, right next
to checking the prop bolt torque.
--
Jay Maynard, K5ZC, PP-ASEL http://www.conmicro.com
http://jmaynard.livejournal.com http://www.tronguy.net
Fairmont, MN (KFRM) (Yes, that's me!)
AMD Zodiac CH601XLi N55ZC http://www.tronguy.net/N55ZC.shtml
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_________________ Jay Maynard, K5ZC
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Martin Pohl
Joined: 30 Jan 2006 Posts: 118 Location: CH-8645 Jona SG, Switzerland
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Posted: Mon Nov 17, 2008 10:36 am Post subject: Re: All 601XL grounded in Netherlands |
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Quote: | 601xl from CZAW also have is that the angle of attack of the wing is flatter |
Just to clarify: The angle of incidence on the CZAW CH601XL is 2° bigger (i.e. steeper) than on the US-version which results in a more nose-down flying attitude at the same airspeed (this was now taken over in the CH650).
I believe that the CZAW engine mount was slightly lengthened to compensate for the light weight engine (and to keep the C.G. at its necessary position).
Martin
CZAW QBK CH601XL
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_________________ Martin Pohl
Zodiac XL QBK
8645 Jona, Switzerland
http://www.pohltec.ch/ZodiacXL/Main.html |
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aerobat
Joined: 07 Nov 2008 Posts: 21 Location: UK
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Posted: Tue Nov 18, 2008 2:22 am Post subject: Re: All 601XL grounded in Netherlands |
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What do other people think about the grounding, I am not convinced that flutter is the problem.
It would appear that a lot of XLs have now been checked and found to have incorrect control cables yet were flying ok.
The fact is there have been several in flight breakups now yet there are many much older types flying around with wood / aluminium creaking and slack cables without dropping out of the sky.
I will not be at all unhappy if the UK authorities say some sort of wing attachment fix is required before mine can fly again.
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David X
Joined: 10 Jan 2006 Posts: 154 Location: Princeton, NJ, USA
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Posted: Tue Nov 18, 2008 9:22 am Post subject: Re: All 601XL grounded in Netherlands |
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You are correct about the gear, the hinges and the trim tab. However, the CZAW sold in the US were to LSA standards and had the heavier Grove spring aluminum gear. The airframe materials come from the US and are identical to what you get in the kit from Missouri. There may be some versions made for other markets ... but I can only speak my experience with those made for the US market.
I don't know that the trim or the hinges have a lot to do with flutter. I would think loose cables would be more critical in that respect. The hinge-less kind of aileron's have more play than the piano hinges (my observation) ... but who is to say that doesn't help rather than hurt. It's really hard to say.
Terry Phillips wrote: | Glenn
You are right. CZAW 601XL's are lighter. But, they are lighter in only one
place: The landing gear.
CZAW used the composite gear sold by Aircraft Spruce. The Aircraft Spruce
landing gear is limited to 550 kg gross, which is less than the Zenair 600
kg (1320 lb) gross. However, I believe that some of the CZAW 601XL's that
made it to the US were registered with 600 kg gross. See:
http://www.aircraftspruce.com/catalog/lgpages/compositelg.php
Other than that, CZAW 601XL's are identical or even beefed up a bit
compared to the standard Zenair 601XL. I believe that all CZAW 601XL's use
the piano hinged aileron and incorporate the electric aileron trim option.
In fact, I believe that if you check with someone who owns a CZAW 601XL,
you'll find that the aileron piano hinge has been beefed up beyond the
standard Zenair piano hinge.
So, if the cable tension is more critical for the CZAW built 601XL's than
for the Zenair 601XL's (personally, I do not believe that it is), the
difference would evidently lie in the hinges or the trim option. (Note that
not all Zenair 601XL's have piano hinges or aileron trim tabs, while all
CZAW 601XL's apparently have those options.)
Terry
At 02:59 PM 11/16/2008 -0800, you wrote:
Quote: | Can someone please clarify?
As I understand it the CZAW 601s have a lower MTOW and are built from
lighter material in some areas, correct?
So, obviously the cable tensions need to be correct regardless, but does
this mean the CZAW versions are more susceptible to the problem?
Glenn
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Terry Phillips ZBAGer
ttp44~at~rkymtn.net
Corvallis MT
601XL/Jab 3300 s .. l .. o .. o .. w build kit - Tail, flaps, & ailerons
are done; working on the wings
http://www.mykitlog.com/N47TP/ |
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_________________ Zodiac 601 XL - CZAW Built - Rotax 912S
DO NOT ARCHIVE |
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Jugle
Joined: 04 Aug 2007 Posts: 47 Location: Victoria, Australia
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Posted: Tue Nov 18, 2008 2:05 pm Post subject: Re: All 601XL grounded in Netherlands |
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So in your original post David, you mention you were contacted by the FAA and the NTSB, apparently because yours is a CZAW 601.
Now, there have been a number of answers to my question about the weight difference in the US & European spec. 601s, which all seem to say that it has nothing to do with how robust the airframe is, but rather relating to the landing gear construction. Fair enough.
We know that flutter can be an issue on all models and the cables need to be checked for tension regularly on all models, so why have they contacted you and not every other owner?
They must have said something along the lines of "Okay, this guy has a European spec 601, we'd better talk to him." Is that purely because they have been grounded there?
Glenn.
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_________________ Glenn Andressen
601XL- Rudder, Stabiliser parts completed, Wing ribs, nose ribs done, 70% Fuselage parts made. |
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pavel569
Joined: 21 Dec 2007 Posts: 77
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Posted: Tue Nov 18, 2008 2:17 pm Post subject: Re: All 601XL grounded in Netherlands |
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I still see no way how to save 100lbs on the gear itself. Maybe on Boeing 747, but 601? I don't think so. I don't have a scale with me right now but my guess would be that the heavy US Zodiac XL gear weights about 35-40lbs.
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_________________ Pavel
CA
Zodiac 601XL
Stratus Subaru EA-81
Tail, flaps, ailerons, wings, fuselage, canopy done ...
"do not archive" |
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PatrickW
Joined: 27 Oct 2006 Posts: 380 Location: Fort Worth, Texas
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Posted: Tue Nov 18, 2008 2:39 pm Post subject: Re: All 601XL grounded in Netherlands |
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Just put mine on the scale. With axles, but without wheels/tires, the big chunk of aluminum weights 47.8 lbs.
- Pat
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ideaz1(at)sbcglobal.net Guest
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Posted: Tue Nov 18, 2008 4:50 pm Post subject: All 601XL grounded in Netherlands |
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Next somebody will tell us they put helium bags in the wings, JEEZ!
Dirk
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David X
Joined: 10 Jan 2006 Posts: 154 Location: Princeton, NJ, USA
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Posted: Tue Nov 18, 2008 6:12 pm Post subject: Re: All 601XL grounded in Netherlands |
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It may be that the NTSB investigator assumed that the aircraft was Euro spec because it was imported. He did not know it was an LSA until I told him. This information is not readily available on the public FAA N-Number lookup. I probably got a call from the FAA to get permission to give my phone number to the NTSB investigator. The FAA guy had a few questions too.
I'm guessing that the NTSB is just following all evidence wherever it takes them. At least a few of the incidents of flutter, in my mind, are related to cable slack (at least the pilots are alive to tell us that their cable tensions were not to spec). I, and others, are keenly interested in what might be behind some of the unexplained fatal incidents.
For now, the obvious thing to do is keep your cables to spec. using a cable tension meter. I was surprised how many around the globe had out-of-spec cables. I will be checking these every 50 hours. It's not a big deal and it affords an opportunity to look inside the fuselage at the rear wing attach points etc.
Jugle wrote: | We know that flutter can be an issue on all models and the cables need to be checked for tension regularly on all models, so why have they contacted you and not every other owner?
They must have said something along the lines of "Okay, this guy has a European spec 601, we'd better talk to him." Is that purely because they have been grounded there? |
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_________________ Zodiac 601 XL - CZAW Built - Rotax 912S
DO NOT ARCHIVE |
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Terry Phillips
Joined: 11 Jan 2006 Posts: 346 Location: Corvallis, MT
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Posted: Tue Nov 18, 2008 7:27 pm Post subject: All 601XL grounded in Netherlands |
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David & Patrick.
Thank you for confirming about the hinges and trim, David.
The pieces are starting to come together. I was surprised that CZAW would
sell their 601XL for US use at 600 kg gross with a gear rated at 550 kg.
Apparently, they did not. The only CZAW 601XL in the US for which I had
definite landing gear information did have the composite gear. But I just
checked and that 601XL's gross was 1232 lbs, not 1320. Substituting the
Grove gear is a very nice option to get back to 600 kg gross. I saw Larry
Winger's gundrilled Grove gear and it was very, very, nice.
The Grove website says that their 601XL gear is rated at 1320 lbs, and
weighs 32.2 lbs, which is about 10 lbs less than the ZAC gear (per 6-G-3).
The Grove gear is 7/8" thick 7075-T6 while the ZAC gear is 3/4" 6061-T6, so
the profile of the Grove gear must be significantly reduced from the ZAC
profile. I wish I had the engineering skills to determine whether
significant weight (i.e., aluminum) could be removed from the ZAC gear
while maintaining strength >= the Grove gear. Ah, well, it would probably
not be worth the effort.
Terry
At 09:22 AM 11/18/2008 -0800, David X wrote:
Quote: | You are correct about the gear, the hinges and the trim tab. However, the
CZAW sold in the US were to LSA standards and had the heavier Grove spring
aluminum gear. The materials come from the US and are identical to what
you get in the kit from Missouri. There may be some versions made for
other markets ... but I can only speak my experience with those made for
the US market.
I don't know that the trim or the hinges have a lot to do with flutter. I
would think loose cables would be more critical in that respect. The
hinge-less kind of aileron's have more play than the piano hinges (my
observation) ... but who is to say that doesn't help rather than hurt.
It's really hard to say.
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Quote: | At 02:39 PM 11/18/2008 -0800, PatrickW wrote:
Just put mine on the scale. With axles, but without wheels/tires, the big
chunk of aluminum weights 47.8 lbs.
- Pat
--------
Patrick
601XL/Corvair
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Terry Phillips ZBAGer
ttp44~at~rkymtn.net
Corvallis MT
601XL/Jab 3300 s .. l .. o .. o .. w build kit - Tail, flaps, & ailerons
are done; working on the wings
http://www.mykitlog.com/N47TP/
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_________________ Terry Phillips
Corvallis, MT
ttp44<at>rkymtn.net
Zenith 601XL/Jab 3300 slow build kit - Tail feathers done; working on the wings. |
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David X
Joined: 10 Jan 2006 Posts: 154 Location: Princeton, NJ, USA
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Posted: Tue Nov 18, 2008 8:13 pm Post subject: Weight savings |
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If by "reduced" you mean thinner, the Grove gear is actually 1/8 inch thicker (if indeed it is 7/8" vs. ZAC 3/4".
10 lbs is significant. Every bit adds up. The paint might weight 3 to 4 lb/gallon after it dries. You can save some weight by replacing the electric flap motor with a pull lever. If you live in a warm climate, use a smaller battery and save a few lbs. The wheels make a big difference depending on what you choose etc. I'm sure there are a lot of weight saving tips out there.
Terry Phillips wrote: |
The Grove website says that their 601XL gear is rated at 1320 lbs, and
weighs 32.2 lbs, which is about 10 lbs less than the ZAC gear (per 6-G-3). The Grove gear is 7/8" thick 7075-T6 while the ZAC gear is 3/4" 6061-T6, so the profile of the Grove gear must be significantly reduced from the ZAC profile.
|
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_________________ Zodiac 601 XL - CZAW Built - Rotax 912S
DO NOT ARCHIVE |
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Terry Phillips
Joined: 11 Jan 2006 Posts: 346 Location: Corvallis, MT
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Posted: Tue Nov 18, 2008 9:21 pm Post subject: All 601XL grounded in Netherlands |
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David
Since 7/8" is thicker than 3/4", by reduced profile I didn't mean
"thinner". By profile, I meant the shape cut from the sheet aluminum, be it
3/4" or 7/8" thick. Probably a poor choice of words.
I don't actually know that the Grove gear is 7/8" thick. That's just the
thickness shown on the Grove website:
http://www.groveaircraft.com/landing_gear.html
Similarly, I haven't measured the thickness of my ZAC gear. But 6-G-3 gives
it as 3/4".
I just checked the yield strength of the two alloys: 73,000 psi for the
7075 vs. 40,000 psi for the 6061. It would appear that the Grove gear is
probably lighter only because it uses a higher strength alloy, which allows
for a smaller profile. Since
weight = area * thickness * density
Assuming the density of the two alloys is the same, and given the Grove
weight of 32.2 lbs and the ZAC weight of 43 lbs, I calculate that the area
of the Grove gear must be ~64% of the area of the ZAC gear. But one could
not achieve that small profile with 6061 because of its lower strength.
Yeah, there are lots of ways to trim 10 or 20 lbs off the takeoff weight.
My wife suggests I start with the 20 lbs around my waist
Terry
At 08:13 PM 11/18/2008 -0800, you wrote:
Quote: | If by "reduced" you mean thinner, the Grove gear is actually 1/8 inch
thicker (if indeed it is 7/8" vs. ZAC 3/4".
10 lbs is significant. Every bit adds up. The paint might weight 3 to 4
lb/gallon after it dries. You can save some weight by replacing the
electric flap motor with a pull lever. If you live in a warm climate, use
a smaller battery and save a few lbs. The wheels make a big difference
depending on what you choose etc. I'm sure there are a lot of weight
saving tips out there.
Terry Phillips wrote:
>
> The Grove website says that their 601XL gear is rated at 1320 lbs, and
> weighs 32.2 lbs, which is about 10 lbs less than the ZAC gear (per
6-G-3). The Grove gear is 7/8" thick 7075-T6 while the ZAC gear is 3/4"
6061-T6, so the profile of the Grove gear must be significantly reduced
from the ZAC profile.
>
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Terry Phillips ZBAGer
ttp44~at~rkymtn.net
Corvallis MT
601XL/Jab 3300 s .. l .. o .. o .. w build kit - Tail, flaps, & ailerons
are done; working on the wings
http://www.mykitlog.com/N47TP/
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_________________ Terry Phillips
Corvallis, MT
ttp44<at>rkymtn.net
Zenith 601XL/Jab 3300 slow build kit - Tail feathers done; working on the wings. |
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jmaynard
Joined: 27 Feb 2008 Posts: 394 Location: Fairmont, MN (FRM)
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Posted: Wed Nov 19, 2008 4:43 am Post subject: All 601XL grounded in Netherlands |
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On Tue, Nov 18, 2008 at 08:26:43PM -0700, Terry Phillips wrote:
Quote: | The Grove gear is 7/8" thick 7075-T6 while the ZAC gear is 3/4" 6061-T6, so
the profile of the Grove gear must be significantly reduced from the ZAC
profile.
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It is. The Grove gear (which AMD uses) requires a spacer to hold it in
position at the front of the gear channel.
--
Jay Maynard, K5ZC, PP-ASEL http://www.conmicro.com
http://jmaynard.livejournal.com http://www.tronguy.net
Fairmont, MN (KFRM) (Yes, that's me!)
AMD Zodiac CH601XLi N55ZC http://www.tronguy.net/N55ZC.shtml
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_________________ Jay Maynard, K5ZC
AMD Zodiac XLi N55ZC |
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Tommy Walker
Joined: 12 Jan 2006 Posts: 442 Location: Anniston, AL 36207
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Posted: Wed Nov 19, 2008 5:42 pm Post subject: Re: All 601XL grounded in Netherlands |
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David,
I tried to send this to you privately, but I don't have your email address.
There is a CZAW 601XL at my airport. It has a gross weight of 1100 lbs. I assume that it is the "European" version of the 601.
I am sure there are others. This airplane came through a company in Florida.
What information about this plane should the owner be aware of?
If you answer, please reply to twalker(at)cableone.net
Thanks,
Tommy Walker in Alabama
N8701
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N25A - Anniston, AL |
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planecrazydld(at)yahoo.co Guest
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Posted: Wed Nov 19, 2008 5:44 pm Post subject: All 601XL grounded in Netherlands |
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but the grove gear is half as wide isn't it?
David L. Downey Harleysville (SE) PA, USA
--- On Tue, 11/18/08, David X <dxj(at)comcast.net> wrote:
From: David X <dxj(at)comcast.net>
Subject: Re: All 601XL grounded in Netherlands
To: zenith601-list(at)matronics.com
Date: Tuesday, November 18, 2008, 11:13 PM
<dxj(at)comcast.net>
If by "reduced" you mean thinner, the Grove gear is actually 1/8 inch
thicker (if indeed it is 7/8" vs. ZAC 3/4".
10 lbs is significant. Every bit adds up. The paint might weight 3 to 4
lb/gallon after it dries. You can save some weight by replacing the electric
flap motor with a pull lever. If you live in a warm climate, use a smaller
battery and save a few lbs. The wheels make a big difference depending on what
you choose etc. I'm sure there are a lot of weight saving tips out there.
Terry Phillips wrote:
[quote]
The Grove website says that their 601XL gear is rated at 1320 lbs, and
weighs 32.2 lbs, which is about 10 lbs less than the ZAC gear (per 6-G-3)
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jmaynard
Joined: 27 Feb 2008 Posts: 394 Location: Fairmont, MN (FRM)
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Posted: Wed Nov 19, 2008 6:05 pm Post subject: All 601XL grounded in Netherlands |
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On Wed, Nov 19, 2008 at 05:44:25PM -0800, David Downey wrote:
Quote: | but the grove gear is half as wide isn't it?
|
Not that narrow...a quick guess without looking at the airplane says it's
2/3 to 3/4 as wide.
--
Jay Maynard, K5ZC, PP-ASEL http://www.conmicro.com
http://jmaynard.livejournal.com http://www.tronguy.net
Fairmont, MN (KFRM) (Yes, that's me!)
AMD Zodiac CH601XLi N55ZC http://www.tronguy.net/N55ZC.shtml
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_________________ Jay Maynard, K5ZC
AMD Zodiac XLi N55ZC |
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rans6andrew
Joined: 23 Nov 2008 Posts: 16 Location: Berks, UK
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Posted: Fri Dec 05, 2008 8:14 am Post subject: Re: All 601XL grounded in Netherlands |
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more from the LAA today:
http://www.lightaircraftassociation.co.uk/HomePage/zenair.html
not much extra info but I hear on the grape vine that they have found cause for concern the XL wing and are working on proving it.
Watch this space.
Andrew. 601UL heading for the paintshop anytime soon.
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_________________ A good way through building a 601UL with 912UL.
Still flying Rans S6 with 503. |
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FlyingMonkey
Joined: 07 Nov 2008 Posts: 4
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Posted: Sat Dec 06, 2008 12:04 am Post subject: Re: All 601XL grounded in Netherlands |
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Terry Phillips wrote: | David
Since 7/8" is thicker than 3/4", by reduced profile I didn't mean
"thinner". By profile, I meant the shape cut from the sheet aluminum, be it
3/4" or 7/8" thick. Probably a poor choice of words.
I don't actually know that the Grove gear is 7/8" thick. That's just the
thickness shown on the Grove website:
http://www.groveaircraft.com/landing_gear.html
Similarly, I haven't measured the thickness of my ZAC gear. But 6-G-3 gives
it as 3/4".
I just checked the yield strength of the two alloys: 73,000 psi for the
7075 vs. 40,000 psi for the 6061. It would appear that the Grove gear is
probably lighter only because it uses a higher strength alloy, which allows
for a smaller profile. Since
weight = area * thickness * density
Assuming the density of the two alloys is the same, and given the Grove
weight of 32.2 lbs and the ZAC weight of 43 lbs, I calculate that the area
of the Grove gear must be ~64% of the area of the ZAC gear. But one could
not achieve that small profile with 6061 because of its lower strength.
Yeah, there are lots of ways to trim 10 or 20 lbs off the takeoff weight.
My wife suggests I start with the 20 lbs around my waist
Terry
At 08:13 PM 11/18/2008 -0800, you wrote:
Quote: | If by "reduced" you mean thinner, the Grove gear is actually 1/8 inch
thicker (if indeed it is 7/8" vs. ZAC 3/4".
10 lbs is significant. Every bit adds up. The paint might weight 3 to 4
lb/gallon after it dries. You can save some weight by replacing the
electric flap motor with a pull lever. If you live in a warm climate, use
a smaller battery and save a few lbs. The wheels make a big difference
depending on what you choose etc. I'm sure there are a lot of weight
saving tips out there.
Terry Phillips wrote:
>
> The Grove website says that their 601XL gear is rated at 1320 lbs, and
> weighs 32.2 lbs, which is about 10 lbs less than the ZAC gear (per
6-G-3). The Grove gear is 7/8" thick 7075-T6 while the ZAC gear is 3/4"
6061-T6, so the profile of the Grove gear must be significantly reduced
from the ZAC profile.
>
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Terry Phillips ZBAGer
ttp44~at~rkymtn.net
Corvallis MT
601XL/Jab 3300 s .. l .. o .. o .. w build kit - Tail, flaps, & ailerons
are done; working on the wings
http://www.mykitlog.com/N47TP/ |
" Assuming the density of the two alloys is the same,..."
They're not though-7075-T6 is an alloy of aluminum ( density of 2.7 grams per/cubic centimeter) and far more dense zinc ( 7.14 grams per cubic centimeter ), ....while 6061 is an alloy of 2.7 gram /cc aluminum and lighter Silicon ( 2.329 g/cc ) and magnesium ( 1.73 g/cc ) .
Interesting discussion , though-and I don't know how far off those densities would alter your calculation, since I don't know how much of each different metal is alloyed with the aluminum -since the second digit is a zero in each case.
===
Terry Phillips wrote: | I was surprised that CZAW would
sell their 601XL for US use at 600 kg gross with a gear rated at 550 kg.
Apparently, they did not. The only CZAW 601XL in the US for which I had
definite landing gear information did have the composite gear. But I just
checked and that 601XL's gross was 1232 lbs, not 1320 |
As you may know, the 1232 pounds is the Canadian Advanced Ultralight maximum gross ( the spec that Chris H wrote when he was still making aircraft in Canada, his starting place in North America) .
He wrote the Canadian aircraft regulation to meet his then new Zodiac HD , -the HD ul model met the original( 1991 ) Canadian Advanced Ultralight spec of 1058 pounds max gross , when the xl came out it met the Canadian spec increase to 1232 pounds.
(1232 lbs = 560 kg )
( scroll to bottom of list )
http://www.tc.gc.ca/CivilAviation/general/CCARCS/advancedullist.htm
With the standard 100-hp Rotax 912S engine a basic European Zodiac XL ULM weighs 265 kg. (585 lbs).
European ultralight aircraft must comply to :
A max gross weight of 450 kg, except in Germany and Finland it is 472.5 kg with rescue system. ( Amphibians are 50 kg higher )
The max empty weight in UK is 265 kg , in Scandinavian countries it is 275 kg , in Germany it's 275 kg plus rescue system.
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Thruster87
Joined: 16 Apr 2008 Posts: 193 Location: Australia
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Posted: Sat Dec 06, 2008 12:17 am Post subject: Re: All 601XL grounded in Netherlands |
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LSA aircraft in Australia can go to 600kg MTOW which includes the 601xl
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