TMann Posted August 13, 2009 Share Posted August 13, 2009 My objective is to avoid the entire ballast issue. I moved my battery forward of FS 0.0 and plan on a second battery plus the pump for the gear where the battery once lived. Once I have it on scales, I may have to move some things around to get it right but the desired result at the end of the day is to have zero ballast and still be forward of the aft CG limit Quote T Mann - Loooong-EZ/20B Infinity R/G Chpts 18 Velocity/RG N951TM Mann's Airplane Factory We add rocket's to everything! 4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done Link to comment Share on other sites More sharing options...
Marc Zeitlin Posted August 13, 2009 Share Posted August 13, 2009 Is it my imagination but don't some sail planes use water for ballast???Yes, in the wings. Not for CG adjustment, but for better penetration speed (raises the speed for best L/D). There's lots of empty room in sailplane wings, and it allows them something cheap to dump DURING FLIGHT. Different set of needs. 1 ft cubed for water might be hard to find, however 1/2 foot, if that is all that is needed seems to be about the size of the volume forward of the forward bulkhead FS0.Not even close. Even 1/2 cubic foot is HUGE. I can barely hold 25 lb of lead in the 1/2 of that space that I've got available. That would imply that I could hold about 5 lb. of water in the whole space. Yes, you are absolutely right about the variation in the density of different sand. That's what the spring scale is for.Can you make this more complex? I pick up my weight and put it in the nose. I pick up my weight and put it in the back. Simple. You want to be wandering around the airport, finding mud, dirt, sand, or whatever happens to be laying around that's not dense enough, digging it up, weighing it, and putting it in <something>. If using steel or lead, both great, some method should be incorporated in the baggage area for securing the ingots, or whatever, when not secured in the nose.Agreed. That's why I have seatbelts in the rear seats, or space behind the seats or inside the "hell hole". Takes about 15 seconds to move and secure the ballast. Quote Marc J. Zeitlin Burnside Aerospace marc_zeitlin@alum.mit.edu www.cozybuilders.org copyright © 2024 Link to comment Share on other sites More sharing options...
Marc Zeitlin Posted August 13, 2009 Share Posted August 13, 2009 My objective is to avoid the entire ballast issue....And with a tandem airplane like the LE that has one known pilot, that's entirely doable and reasonable. The problem is the CG movement when adding the second person in the front seat of the COZY - the CG moves a LOT, and ballast is an absolute necessity. If you set your COZY up for no ballast when solo, you'll have a front passenger seat weight capacity of about 100 lb. - you'd be able to take children, but not much else, and you'd be at the forward CG when doing it. Completely non-optimal. Quote Marc J. Zeitlin Burnside Aerospace marc_zeitlin@alum.mit.edu www.cozybuilders.org copyright © 2024 Link to comment Share on other sites More sharing options...
Drew Swenson Posted August 14, 2009 Share Posted August 14, 2009 Don't know why people make this a big deal. I do it sort of like Marc. If I have a passenger that is going to depart, I put the weight in the back and shift it up front after my pax leaves. If I will have my pax for my entire trip, I leave the wt at home. Quote Link to comment Share on other sites More sharing options...
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