Just to be clear. In my responses below I am not trying to be argumentative or tell you how to do anything. I know sometimes these conversations about stunt design and the “why?” seem to get a bit heated. I am just having conversation about design and stuff. I love this stuff and I am always learning.
OK I will lay it out for everyone. I am learning a lot about electrics and have been totally convinced this is the way to go. My last Crossfire flies like a 40 OZ airplane because it is. In my quest for lighter wing loadings I have some ideas. Most of which are old school. I like beam wings. Easy to build and light at the extremity's. When you grab a airplane with the nose pointed towards you and roll it tip to tip you can feel the inertia. Less is better. Less wood,less paint = less inertia
What problems are you seeing that are pushing you to change the design?
Why are you looking for lighter wing loading (besides the long standing “idea” that less loading is always better)?
Have you seen an
issue that is making you think less loading would correct?
Round is stronger than flat. Egg shell sides = thinner wood. So for my next plane it will be a beam wing ,egg shell fuse ad built up stab and elevators. My last stab was 2.5 OZ including hinges and horn. That will be hard to top but I will try.
Eggshell construction will be interesting. Will you please show how you go about this?
I have been thinking the electric world of planes could benefit from this construction method as you are no longer dealing with all the vibrations. You could in fact build a glass molded shell with only one or two formers and ULTRA thin that won’t fail because it is not fighting vibrations. It will be plenty strong to resist twisting and will come out of the mold ready for paint making it ultimately lighter. I see sail planes with thin round fuses that weigh nothing. They are super strong too they take tons or pressure on a wench launch.
Don’t sacrifice torsional rigidity for light weight. It will fly like crap if it flexes. 2.5 oz on your last one is pretty darn light.
While you are grasping you plane one hand one each side of the fuse at the wing , lift the tail up and down, Feel the momentum. This is bad so the lighter you can make the ends the better. I do like this long nose and reward battery location. The last plane I built tracks like a bullet and turn like a combat ship. The best part is it locks.
While the momentum you feel in your hand feels bad to you in theory. Your last two sentences, composed from actual flight data compiled in your experience with the model, tell you a different story. There is enough elevator size and they are far enough away from the CG to more than handle, and stop, the momentum the stab and the rest of the plane cause during rotation. Holding it in your hand and waiving it is not telling you the whole story.
Flying it
is.Don’t change the design to fix and issue that isn’t there in flight. I, and many others, have done that very thing only to see 100s of hours wasted.
The new plane will use a thinner airfoil and I can get away with that if its light. Less parasitic drag mean less drag and battery usage.
Please be very careful here as others have noted this may not the way to go. More often than not we, the collective modeling community as a whole, miss our target weight on the heavier side. It could be 1 oz, it could be 5 oz. But making the wing thinner will make the weight target that much more important to getting a plane that flies well. You have already proven to yourself that it will perform very well at the weight you have now.
What about the new design and the new plane’s flight characteristics are telling you it absolutely has to have a thinner wing?
Sure the idea that less drag is better always is attractive in general but if this specific design already performs well with the current amount of drag placed on it how will making have less drag be better? Where is it faltering now due to the amount of drag placed on it?
Would you be able to reduce the wing thickness enough to reduce the drag enough to get you to a lighter smaller battery?
That is the question.
If you can and you still think it will be strong enough and thick enough then you can make a serious weight reduction. If you can’t then reducing the thickness of the wing to carry the same battery is all for nothing.
Your beam wing should have a tiny bit less thickness anyway as it has valleys between each rib. Across the span that should add up.
Going against your initial thought you could actually thicken the wing by about 1/8”, 1/16” on top and bottom at the high point and probably not notice one single gram of difference in the finish weight yet it would carry more weight if missed target happens again. Just a thought.
I am just writing notes down and babbling so any ideas are helpful. Look for the new build to appear in the next few days.
Oh yeah, to get the weight you
really want stay away from that rattle can primer.
I can’t wait to see it come together.
Topic: Cutting wood for my next plane (Read 3121 times)
