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#1
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Cambridge 302 and Super netto
Can some-one please explain the difference between netto and Super Netto as
used on the Cambridge 302 variometer. Also what should the 302 be set to? Thanks Ross |
#2
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Yes. This is an area where the 302 is weak and something
I wish Cambridge would rectify. 'Netto' should display the vertical motion of the air mass (as opposed to the vertical motion of the glider)..so in still air, it would show zero, even if your glider is decending at 130 feet per minute. In gently rising air, it would start to show, say, 0.5 up, in sinking air, it shows down. This display means you can seek out rising air and so maximise your glide angle, without the need to stop and turn. It displays what the airmass is doing irrespective of the sink rate or speed of your glider. 'Super Netto' shows the climb rate you could achieve if you stopped to circle at your best climb rate...in effect this means it only functions differently from a t/e vario at higher speeds, when it removes the additional sink rate caused by you flying at 100kts rather than 50kts. Netto is a really useful function in countries with weaker lift (like the UK) and it is a real issue not having this function in an otherwise excellent vario....come on Cambridge, implement the *****function properly! Chris At 05:54 12 September 2003, Ross Biggar wrote: Can some-one please explain the difference between netto and Super Netto as used on the Cambridge 302 variometer. Also what should the 302 be set to? Thanks Ross |
#3
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Chris,
You can select netto, super-netto or always TE in cruise mode for the 302 using the 300 Utility or a 303. John Galloway At 06:48 12 September 2003, Chris Davison wrote: Yes. This is an area where the 302 is weak and something I wish Cambridge would rectify. 'Netto' should display the vertical motion of the air mass (as opposed to the vertical motion of the glider)..so in still air, it would show zero, even if your glider is decending at 130 feet per minute. In gently rising air, it would start to show, say, 0.5 up, in sinking air, it shows down. This display means you can seek out rising air and so maximise your glide angle, without the need to stop and turn. It displays what the airmass is doing irrespective of the sink rate or speed of your glider. 'Super Netto' shows the climb rate you could achieve if you stopped to circle at your best climb rate...in effect this means it only functions differently from a t/e vario at higher speeds, when it removes the additional sink rate caused by you flying at 100kts rather than 50kts. Netto is a really useful function in countries with weaker lift (like the UK) and it is a real issue not having this function in an otherwise excellent vario....come on Cambridge, implement the *****function properly! Chris At 05:54 12 September 2003, Ross Biggar wrote: Can some-one please explain the difference between netto and Super Netto as used on the Cambridge 302 variometer. Also what should the 302 be set to? Thanks Ross |
#4
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Chris,
I usually use the super-netto but I have tried the netto on a couple of flights. To be honest I find the super-netto a bit confusing because if I set the 302 time constant to 3 seconds my 302 and back up Borgelt B40 needles seem to always closely match each other no matter what speed I fly. However with the 302 on the bench and the airspeed inlet pressured to simulate flight the super - netto seems to be correctly set up. The netto itself works on the bench and seems to make sense in flight. And yes, the 1.5 knot up on the ground (and on the bench) is compatible with the netto being switched on. My own gripe about the 302 is the lack of a bugs adjustable speed to fly in the vario. From past reactions to this observation noone else seems to think that is an ommission and are happy to have a bugs adjusted final glide height calculation on Glide Nav/Winpilot and then fly cruise speeds based on a different polar;-) I would prefer to fail to follow accurate data than to fail to follow inaccurate data. John Galloway At 18:12 12 September 2003, Chris Davison wrote: John, do you use Netto and does it work? I have just had one of those 'I may be an idiot' moments....the issue being when I have set the vario to Netto in the past, with the glider on the ground, the needle points to about 1.5kts up....which I have just realised it what it should do...as it is assuming if the glider is maintaining altitude it must be in rising air eauivalent to the sink rate.....DOH. Chris At 15:18 12 September 2003, John Galloway wrote: Chris, You can select netto, super-netto or always TE in cruise mode for the 302 using the 300 Utility or a 303. John Galloway At 06:48 12 September 2003, Chris Davison wrote: Yes. This is an area where the 302 is weak and something I wish Cambridge would rectify. 'Netto' should display the vertical motion of the air mass (as opposed to the vertical motion of the glider)..so in still air, it would show zero, even if your glider is decending at 130 feet per minute. In gently rising air, it would start to show, say, 0.5 up, in sinking air, it shows down. This display means you can seek out rising air and so maximise your glide angle, without the need to stop and turn. It displays what the airmass is doing irrespective of the sink rate or speed of your glider. 'Super Netto' shows the climb rate you could achieve if you stopped to circle at your best climb rate...in effect this means it only functions differently from a t/e vario at higher speeds, when it removes the additional sink rate caused by you flying at 100kts rather than 50kts. Netto is a really useful function in countries with weaker lift (like the UK) and it is a real issue not having this function in an otherwise excellent vario....come on Cambridge, implement the *****function properly! Chris At 05:54 12 September 2003, Ross Biggar wrote: Can some-one please explain the difference between netto and Super Netto as used on the Cambridge 302 variometer. Also what should the 302 be set to? Thanks Ross |
#5
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On Fri, 12 Sep 2003 17:48:03 +1200, "Ross Biggar"
wrote: Can some-one please explain the difference between netto and Super Netto as used on the Cambridge 302 variometer. Also what should the 302 be set to? Thanks Ross Please see the article on our website under articles called "basic glider instruments" That will explain all. Mike Borgelt Borgelt Instruments www.borgeltinstruments.com |
#6
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On 12 Sep 2003 20:26:36 GMT, John Galloway
wrote: My own gripe about the 302 is the lack of a bugs adjustable speed to fly in the vario. From past reactions to this observation noone else seems to think that is an ommission and are happy to have a bugs adjusted final glide height calculation on Glide Nav/Winpilot and then fly cruise speeds based on a different polar;-) I would prefer to fail to follow accurate data than to fail to follow inaccurate data. John Galloway The B50 does this properly and has done since its inception in 1995. Mike Borgelt Borgelt Instruments |
#7
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What I got from Cambridge is that both of you are partially
correct. Yes, you can transfer a bugs setting to the 302 and you can also read it back out. However, I was told by Cambridge that the instrument does not 'currently' use the bugs setting to degrade the polar information that the 302 contains. That was about a year ago though so perhaps that has changed with one of the later firmware versions. Later!-MarkAt 03:06 13 September 2003, Eric Greenwell wrote:In article , says... My own gripe about the 302 is the lack of a bugs adjustable speed to fly in the vario. From past reactions to this observation noone else seems to think that is an ommission and are happy to have a bugs adjusted final glide height calculation on Glide Nav/Winpilot and then fly cruise speeds based on a different polar;-)Are you sure of this? The vario has a page for setting bugs, so I assume it is used for the speed fly. Since the vario doesn't have a final glide calculation, and the bug setting in Glide Nav is transferred to the vario if you set it there, I can't think of any other reason for having that page. -- !Replace DECIMAL.POINT in my e-mail address with just a . to reply directlyEric GreenwellRichland, WA (USA) |
#8
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My own gripe about the 302 is the lack of a bugs adjustable speed to fly in the vario. From past reactions to this observation noone else seems to think that is an ommission and are happy to have a bugs adjusted final glide height calculation on Glide Nav/Winpilot and then fly cruise speeds based on a different polar;-) Are you sure of this? The vario has a page for setting bugs, so I assume it is used for the speed fly. I can't seem to find this bug setting on the "302 Operator's Card" on the Cambridge website. Am I looking in the wrong place? Since the vario doesn't have a final glide calculation, and the bug setting in Glide Nav is transferred to the vario if you set it there, I can't think of any other reason for having that page. -- !Replace DECIMAL.POINT in my e-mail address with just a . to reply directly Eric Greenwell Richland, WA (USA) |
#10
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That's my point - you can configure winpilot/GlideNav
for a bugs adjusted final glide height calculation on your PDA but there is no capability for the 302 to accept a bugs adjusted polar from either the PDA or a 303. This is confirmed by CAI who, when I queried this, said there was no need for a bugs page on the 302 or the 303 because the 302 couldn't use it. It seems such a simple capability to add to the 302 - just add another bugs page to the vario, like the ballast one, and calculate the adjusted polar for the STF. To me it is extraordinary that something all other speed directors do (including the L/S-Nav) cannot be done on a 302. After several attempts to discuss this with CAI I did get a reply that the subject would be put to the developers for consideration. This was before the most recent reorganisation. Perhaps some other owners might like to take this up if they feel the same as I do. Maybe you don't get bugs or rain in US but we sure as hell do here in Scotland:-) John Galloway At 05:36 13 September 2003, Eric Greenwell wrote: Nope. I got confused - it's the ballast setting that's on the vario, not the bug setting. -- !Replace DECIMAL.POINT in my e-mail address with just a . to reply directly Eric Greenwell Richland, WA (USA) |
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