Long glider trailers generally require significant draw bar load to make them stable. Rule of thumb says 10% of trailer weight, but I know you can generally get away with less. On a big trailer I have found that 60kg is usually enough. On a small to medium car this will require load transfer bars to keep appropriate weight on the front wheels.
Unfortunately when we do a retrieve we travel one way unladen. Consequently sufficient load is required on the draw bar to make the unladen trailer stable. Consequently if we want the trailer stable in both conditions the total centre of gravity of the trailer parts needs to end up over the axle or slightly forward of it. Generally if the trailer is set up for stable operation unladen it is easiest to achieve the laden condition by placing the fuse in nose first and the wings in tip first. In many cases the wings determine the length of the trailer box and there is some room to move the fuse fore and aft. This and the tailplane position provide some opportunity to fine tune the laden balance of the trailer. Redmond Quinn ************************************************************ ----- Original Message ----- From: "Roger Druce" <[EMAIL PROTECTED]> To: "'Discussion of issues relating to Soaring in Australia.'" <aus-soaring@lists.internode.on.net> Sent: Friday, 17 June 2005 12:10 Subject: RE: [Aus-soaring] Looooong trailer registration > Rear overhang is fundamentally bad news and the weight distribution with the > German two seater glider trailers having the wing roots to the front and the > fuselage nose to the front is bad news. Sure you get the best riggability > that way and having regard to the trailer clamshell layout. > > I have just spent hours on multiple spreadsheets working out the CofGs of > the different two seater trailer layout configurations, both bare glider, > glider plus carrying fittings and then all that plus trailer structure and > cladding. > > My money is on less riggability convenience but better trailer stability > characteristics from a layout that gets the axles a long way back, ie wing > roots to rear, fuselage nose to front and with auxiliary bits and pieces > stowed within sideways opening rear door. Less tail to wag the dog. See > the article by Nelson Funston in "Technical Soaring" July 1989. That's what > I am doing with my trailer design. > > If you can move the axles back to reduce the rear overhang without > increasing the towbar load to an unacceptable extent then do it. You might > fit a carry box behind the axle and below the floor with a pull out tray to > relocate a significant proportion of the odds and ends stowed at the front > of the trailer. You might think they don't weigh much but they do. It does > help get the CofG back. Or move the spare wheel (15 to 18 kg ie > non-trivial) to the rear of the trailer perhaps on one side of the fin in a > removeable but strong tiedownable frame or box, or on the rear door exterior > somehow. > > With respect Graham don't persist with trying to justify 5.23 m overhang. > Get on with reducing the overhang by doing things which enable you to shift > the axles aftwards. Yes it takes effort and/or money. However it is really > good value for trailer safety for the long term. > > Cheers > Roger Druce > > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Jason and > Jemima Armistead > Sent: Friday, 17 June 2005 12:03 AM > To: Discussion of issues relating to Soaring in Australia. > Subject: Re: [Aus-soaring] Looooong trailer registration > > Graham > > At Southern Cross GC (Camden, NSW), our DG-1000 trailer (a twin axle Anschau > Komet) had too much overhang, and we had to move the axle position slightly > to comply with the 5m ruling. The RTA inspector (Jim Stanley > IIRC) would not budge beyond that. > > Thankfully we had a good mechanic who was a friend of the club and did the > work for us at a very reasonable price. > > And the trailer actually seemed to be better balanced after the axle was > moved ! > > Cheers > > Jason Armistead > > At 11:56 PM 16/06/2005, you wrote: > >As John Giddy reminded me a few weeks ago, I live in the Sate with no > >published ADR exemptions for glider trailers - NSW. I now know that > >policy is to allow exemptions against the overhang limit under the ADRs > >(3.7m) up to 5m, very similar to Victoria and SA rules. > > > >A trailer we're considering buying for a two-seater has an overhang of > >5.23m. I'd be interested to hear from anybody who has (relatively) > >recently successfully registered a trailer with overhang greater than > >5m. Is it possible? Under what conditions? How did you go about it? > > > >Any advice would be appreciated. > > > >Graeme Cant > > > > > >_______________________________________________ > >Aus-soaring mailing list > >Aus-soaring@lists.internode.on.net > >To check or change subscription details, visit: > >http://lists.internode.on.net/mailman/listinfo/aus-soaring > > > > _______________________________________________ > Aus-soaring mailing list > Aus-soaring@lists.internode.on.net > To check or change subscription details, visit: > http://lists.internode.on.net/mailman/listinfo/aus-soaring > > > _______________________________________________ > Aus-soaring mailing list > Aus-soaring@lists.internode.on.net > To check or change subscription details, visit: > http://lists.internode.on.net/mailman/listinfo/aus-soaring _______________________________________________ Aus-soaring mailing list Aus-soaring@lists.internode.on.net To check or change subscription details, visit: http://lists.internode.on.net/mailman/listinfo/aus-soaring
