Thanks Noel, It seems my message got out even though I got a reply saying that it had not.
I am corresponding with a sailplane builder in the USA who wants to just use sealed spaces in the leading edge as tanks. I am trying to persuade him to use ballast bags, On Tue, Aug 29, 2017 at 8:15 PM, Noel Roediger <[email protected]> wrote: > Peter. > > > > A long time ago several old/new sailplanes eg. Mosquito’s, Cirrus etc.. > suffered water leakage from their tanks into surrounding foam structure to > such a degree lower skins separated from the foam. > > > > As a result a test was required to check the integrity of ballast tanks > at each Form 2 inspection. > > > > I can only suppose the tanked sailplanes you’re referring to failed the > test. > > > > Noel. > > > > *From:* Aus-soaring [mailto:[email protected]] *On > Behalf Of *Peter Champness > *Sent:* Tuesday, August 29, 2017 6:40 PM > *To:* Discussion of issues relating to Soaring in Australia. > *Cc:* Gliding Australia Forum; Bruce Taylor > *Subject:* Re: [Aus-soaring] [gfaforum] RE: water bags and tanks > > > > With respect to ballast bags, can anyone tell me why so many older gliders > (without ballast bags) can no longer carry water? What is the problem? > > > > On Mon, Aug 28, 2017 at 10:38 PM, Noel Roediger <[email protected]> > wrote: > > The best ballast bags I ever used were made by Clipper Plastics – a > Melbourne based company. > > > > They had patterns for all sailplanes requiring such and the bags were > reasonably priced. > > > > Noel. > > > > *From:* Bruce Taylor [mailto:[email protected]] > *Sent:* Monday, August 28, 2017 3:32 PM > *To:* 'Justin Sinclair'; 'Gary Stevenson' > *Cc:* 'Discussion of issues relating to Soaring in Australia.'; 'Anthony > Smith'; 'Gliding Australia Forum' > *Subject:* RE: [gfaforum] RE: water bags and tanks > > > > Hi Gary and all, > > > > In regard to sourcing ballast bags, there is a company at Currumbin in Qld > called Turtle Pac who make all kinds of water and fuel bags for aviation > and marine use. You will find them at http://www.turtlepac.com/ > > > > I have used them in the past, as have a number of other gliding people, > and they appear to provide a good quality product and are very pleasant and > easy to deal with. > > > > Speaking of “Super ships” and matters of weight and balance, it is my > experience that as weights and wing-loadings inevitably increase, then the > chance of getting the loading wrong enough to matter also increases. The > JS1 is a beautiful glider to own and fly, but it is the first glider that I > have been involved with that has a real potential to be loaded well outside > of its C of G limitations. Particularly in 21m span, the large wing ballast > load, two separate tail tanks, jet fuel load and of course various pilot > weights require that you do actually sit down with the supplied loading > spreadsheet and put all the correct numbers into the calculation. > Wing-loadings close to 60kg/sq m are a real hoot to fly with, but need to > be treated with much respect. > > > > On the upside, the EASA-specified certification flight testing is now > incredibly rigorous, so you can be assured that if you do get the numbers > wrong, or have a ballast-dump malfunction, the glider will be doing its > best to keep you alive. Things have changed since gliders like the Cirrus > were certified! Spinning the JS1C/21m with a fully asymmetric ballast load, > with the C of G WAY behind the aft limit, makes for particularly exciting > viewing! It’s on Youtube somewhere. > > > > Cheers, BT. > > > > *From:* Justin Sinclair [mailto:[email protected] > <[email protected]>] > *Sent:* Monday, August 28, 2017 7:38 AM > *To:* Gary Stevenson > *Cc:* Discussion of issues relating to Soaring in Australia.; Anthony > Smith; Gliding Australia Forum > *Subject:* Re: [gfaforum] RE: water bags and tanks > > > > My only comment having been involved as CFI of a club that has had an > asymmetric balance accident would be that *"if"* you can pick that you > have asymmetry make sure do a fast landing. > > > > I am not sure of the speed or flap setting but logic would dictate > something above your normal fully ballasted/slow thermalling speed. The > idea would be to lower the wing onto the ground before you lose aileron > effectiveness, but do not do the traditional stall it on landing otherwise > you get a big surprise as the heavy wing drops first. > > > > The issue with asymmetry should be structural not aerodynamic. Even if one > wing has 200lts of water in it you average wing can easily develop enough > angle of attack to pull 3G or 600lts/kg, so as long as you have speed/AoA > you will be fine. > > > > My only other advice would be if you use tape to cover the vent holes > instead of wing sticks make sure you do a proper ABCD walk around just > before you jump in the seat and use any colour tape other than white. > > > > Justin > > > > Justin Sinclair > > 17 Queen St > > Scarborough Qld > > > > 0421061811 > > > On 28 Aug 2017, at 12:18 am, Gary Stevenson <[email protected]> wrote: > > Hi Noel, > > Tend to agree with you here. > > > > Re “twisted” I am sure that this does not apply only to the bags. Think > about some of the pilots you know! > > > > You say *“Generally a sailplane will not display an imbalance until > stalled. One wing doesn’t know it’s heavier than its partner until then.”* > A very interesting point, which I have had the misfortune to inadvertently > explore a little bit, but – thank God – never seriously in the air. > > > > Without doubt the use of water ballast introduced a whole new dimension > to gliding, as, just co-incidentally Mike B mentioned in a concurrent post. > However it use is something that should never be treated *lightly* > [groan]. A couple of hundred litres of ballast will turn your pussy cat > into a tiger: In the glide; into a missile ..... almost. Take care that > you are not lined up on one of your mates. > > > > You say “*A number of prototype sailplanes have been lost while testing > their ability to remain controllable at the stall with max. Imbalance” * I > have never had the chance to own/fly a current “super-ship”, but from the > literature , they have (as a minimum), inboard tanks, outboard tanks, and > fuselage tanks. It would seem to me that the situation could become > somewhat fraught, if the slightest thing goes wrong with the dumping > arrangement. > > > > Would any knowable person like to make comment here? > > > > Finally we come to the important practical question of “good ballast > bags”. It would seem that these are becoming hard to source, due to > potential liability issues. Who in Australia, or elsewhere, are making new > replacement bags? > > > > Regards, > > Gary > > > > > > > > > > > > > > > > > > > > > > *From:* Aus-soaring [mailto:[email protected] > <[email protected]>] *On Behalf Of *Noel Roediger > *Sent:* Sunday, 27 August 2017 10:18 PM > *To:* 'Anthony Smith'; 'Discussion of issues relating to Soaring in > Australia.'; 'Gliding Australia Forum' > *Subject:* Re: [Aus-soaring] [gfaforum] RE: American Soaring Symposia > > > > Thanks Anthony. > > > > The final question asked of Wil re assymetric water ballast merits further > comment particularly for those who fly sailplanes with bags instead of > tanks. > > > > I believe good ballast bags far outweigh the problems exhibited by rigid > tanks which often leak into the surrounding structure. > > > > Having said that I don’t know of any “bagged” tank that is not extended > and held in place by a rear cord. > > > > In reality bags should be held by two cords. One at its rear as is the > norm but also one at its front to eliminate the possibility of its leading > edge falling over the aft edge and becoming twisted. > > > > > > > > Regards > > > > Noel. > > > > *From:* Anthony Smith [mailto:[email protected] > <[email protected]>] > *Sent:* Sunday, August 27, 2017 6:32 PM > *To:* 'Discussion of issues relating to Soaring in Australia.'; 'Gliding > Australia Forum' > *Subject:* [gfaforum] RE: [Aus-soaring] American Soaring Symposia > > > > Part of the Wil Schumann paper is here: > > > > http://www.betsybyars.com/guy/soaring_symposia/72-modif.html > > > > *From:* Aus-soaring [mailto:[email protected] > <[email protected]>] *On Behalf Of *Ron Sanders > *Sent:* Sunday, 27 August 2017 6:22 PM > *To:* Gliding Australia Forum <[email protected]>; Discussion > of issues relating to Soaring in Australia. <[email protected]. > au> > *Subject:* [Aus-soaring] American Soaring Symposia > > > > Any body got any idea where is can get any of these publications from the > seventies?? > > Wil Schumann did a clean up of a libelle that i would like to read about > again. > > > > Ron > > -- > You received this message because you are subscribed to the Google Groups > "Gliding Australia Forum" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/a/ > glidingaustralia.org/group/gfaforum/. > > > > [image: Image removed by sender.] > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> > > Virus-free. www.avg.com > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> > > > > -- > You received this message because you are subscribed to the Google Groups > "Gliding Australia Forum" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/a/ > glidingaustralia.org/group/gfaforum/. > > -- > You received this message because you are subscribed to the Google Groups > "Gliding Australia Forum" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/a/ > glidingaustralia.org/group/gfaforum/. > > -- > You received this message because you are subscribed to the Google Groups > "Gliding Australia Forum" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/a/ > glidingaustralia.org/group/gfaforum/. > > > _______________________________________________ > Aus-soaring mailing list > [email protected] > http://lists.base64.com.au/listinfo/aus-soaring > > > > _______________________________________________ > Aus-soaring mailing list > [email protected] > http://lists.base64.com.au/listinfo/aus-soaring > >
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