by staubkorb » Thu Oct 13, 2016 1:59 pm
Hi Andrew, and welcome to Small flying Arts!
You may find that it will likely take a few days to get answers, as the Forum is not yet fully active/announced and is still in the 'set-up' phase, but we're getting there!
To start with your questions, building as light as possible is one of the prime goals for successful Free Flight which entails careful wood selection, using glues intelligently (there are many different types that we can use) and using only enough to get the job done (VERY little). Guillow's models are very nice but are 'commercial' and thus subject to mass production rules - using wood available (not always the best/lightest) and generic plastic parts that may or ma not really fit the subject. They HAVE improved over the past couple of years with laser cutting and better wood selection, thanks to modelers who are acting as consultants, but the kits are designed to be multi-purpose (rubber/fuel/electric FF/rc/CL) in one box - this demands compromise = added weight.
Lightening a stock kit usually means removing as much material from the sheet formers as possible without ruining the structural strength - hogging out the center to within approx. 1/4 inch of the stringer notches, wing-tip parts can be narrowed and the trailing edges of the wings can be 'holed'.
Glues: CA glue is great, but inherently HEAVY - what goes on is what you'll end up with, like epoxy - and is nearly impossible to sand once cured, especially on S&T models. It does have its place when instant grab is needed in an area where sanding won't be an issue and is applied with a pin type applicator (one TINY drop). CA also has a penchant for getting on the wrong part or wicking thru wood, attaching itself to the wrong spot (usually the fingers). Using MEDIUM helps, but the joint can end up heavier than the same join with the thin stuff. I use CA on occasion, but my glue of choice is UHU Hart, thinned 50-50 with acetone. Alternatives are DUCO, Testor's Balsa cement, Ambroid (if you can find it and are not put off by the dark amber color) - also thinned. There are a few others that have been "discovered" recently and are still being evaluated, but I can't comment on them as they are unavailable to me.
I' not that familiar with the 403 Spitty, but I DO know that it is a viable flyer. The size is in it's favor and if there is the necessary decalage (the incidence difference) of ~ 3°, it should fly. The plan should show a suggested balance point for each power system. Test glide as suggested on the plan over the tallest grass you can find and on a calm day (hopefully). I would not recommend hinged surfaces, as they WILL get bumped out of kilter immediately after you find the optimum setting and adds weight back where you definitely don't want it. Some have done so with great success, but they usually end up gluing the surfaces solid. Make the stab slot/mount so that you can adjust the complete stab with shims, gluing it solid once the sweet spot is determined.
More later.. and post some photos!
Pete
Hi Andrew, and welcome to Small flying Arts!
You may find that it will likely take a few days to get answers, as the Forum is not yet fully active/announced and is still in the 'set-up' phase, but we're getting there!
To start with your questions, building as light as possible is one of the prime goals for successful Free Flight which entails careful wood selection, using glues intelligently (there are many different types that we can use) and using only enough to get the job done (VERY little). Guillow's models are very nice but are 'commercial' and thus subject to mass production rules - using wood available (not always the best/lightest) and generic plastic parts that may or ma not really fit the subject. They HAVE improved over the past couple of years with laser cutting and better wood selection, thanks to modelers who are acting as consultants, but the kits are designed to be multi-purpose (rubber/fuel/electric FF/rc/CL) in one box - this demands compromise = added weight.
Lightening a stock kit usually means removing as much material from the sheet formers as possible without ruining the structural strength - hogging out the center to within approx. 1/4 inch of the stringer notches, wing-tip parts can be narrowed and the trailing edges of the wings can be 'holed'.
Glues: CA glue is great, but inherently HEAVY - what goes on is what you'll end up with, like epoxy - and is nearly impossible to sand once cured, especially on S&T models. It does have its place when instant grab is needed in an area where sanding won't be an issue and is applied with a pin type applicator (one TINY drop). CA also has a penchant for getting on the wrong part or wicking thru wood, attaching itself to the wrong spot (usually the fingers). Using MEDIUM helps, but the joint can end up heavier than the same join with the thin stuff. I use CA on occasion, but my glue of choice is UHU Hart, thinned 50-50 with acetone. Alternatives are DUCO, Testor's Balsa cement, Ambroid (if you can find it and are not put off by the dark amber color) - also thinned. There are a few others that have been "discovered" recently and are still being evaluated, but I can't comment on them as they are unavailable to me.
I' not that familiar with the 403 Spitty, but I DO know that it is a viable flyer. The size is in it's favor and if there is the necessary decalage (the incidence difference) of ~ 3°, it should fly. The plan should show a suggested balance point for each power system. Test glide as suggested on the plan over the tallest grass you can find and on a calm day (hopefully). I would not recommend hinged surfaces, as they WILL get bumped out of kilter immediately after you find the optimum setting and adds weight back where you definitely don't want it. Some have done so with great success, but they usually end up gluing the surfaces solid. Make the stab slot/mount so that you can adjust the complete stab with shims, gluing it solid once the sweet spot is determined.
More later.. and post some photos!
Pete