ORIGINAL: Marcol
Hi there,
Just reading the posts on the L19 and in particular the weight of the 1/4 scale one. I have the Vailly 1/4 scale Bird Dog and its weight came out at exactly 25 lbs.
I regard myself as a very light builder, but I just don't see where I could have saved 10lb !
I tend to agree. The weight of the wood alone in my 1/4 Vailly Dog is 10-1/2 pounds (I piled it all on a scale). So, add the engine, cowl, electrics, landing gear, glue, cover, paint and hardware and only gain 4-1/2 pounds? The covering and paint alone on my 1/5 WACO weighs 4-1/2 pounds.
What you said about sacrificing true scale for flyability is true; sometimes it makes for an easier build, but sometimes is critical for control. I had some questions regarding my plans, so I e-mailed Roy Vaillancourt the other day. I got a reply in less than 6 hours. One of my questions was what in particular had been modified from true scale on these plans; his reply was this:
1- the area at the rear portion of the cabin above the rear side windows, at the wing root. The full scale has a "jog", or angle, and this was changed to make a straight line wing root, easier for the average builder. He also commented that few people change it, and judges rarely catch it. I think it looks ....fat... and I have worked about half of today revising the plans and recutting fuse former #4 to bring it back to scale. I will modify the wing root to fit when I build the wings. It is a fairly simple fix.
2-Landing gear is thicker in material cross-section and wider in the side view. This is because of the material used and the strength needed. Full scale gear is spring steel, while the model gear is aluminum.
3-Horizontal stabilizer incidence is zero to +1 on the model "The scale angle just doesn't work for the model. Don't even think about fixing this one or you'll only fly it once" to put it in Roy's words. The scale incidence is about -2 degrees
He said that everything else was "good", meaning very scale.
Marcol, I'd like to see some pix of your BirdDog. What do you have pulling it around? I have a ZDZ-50NG thatI bought specifically to use, but after measuring, find that the spark plug cap will need a clearance hole in the cowl bottom, and I don't want to do it. I have found a 50cc twin that will fit in the cowl without cuts, thinking hard about getting it (LS50 twin, from LS Pro engines). It weighs only a couple of ounces more than the ZDZ single.