Scale Pitts S1-T, S1-S, and a Challenger.

[acerc]

I’ve been debating Poly-Fiber versus Ultracote for the Python 100, and just can’t make up my mind.

I missed this. I have numerous rolls of Ultracote so when I get back to the covering I will make a 12" square frame and finish it as I go along. When done I can weigh the Stits and Ultracote. It would be nice to know for sure exactly what the difference is.

 

[Snoopy1]

I do know that Ultracote weight is 0.3 oz per square foot.

 

[acerc]

Speaking of weight, how many account for balance top to bottom from the datum or thrust line? Would this not cause falling off to one side when doing a maneuver such as knife edge? I have noticed most airframes have everything mounted below this line, including the bulk of the engines offset weight like mufflers.

 

[WMcNabb]

Speaking of weight, how many account for balance top to bottom from the datum or thrust line? Would this not cause falling off to one side when doing a maneuver such as knife edge? I have noticed most airframes have everything mounted below this line, including the bulk of the engines offset weight like mufflers.

Would definitely be interesting to know, not that my piloting skills are mature enough to notice.
We are aware of the rigs built to measure fore and aft CG along the fuselage axis, now image the rigs needed to measure above and below the thrust line.

 

[acerc]

Would definitely be interesting to know, not that my piloting skills are mature enough to notice.
We are aware of the rigs built to measure fore and aft CG along the fuselage axis, now image the rigs needed to measure above and below the thrust line.

Well, I actually do it and it really make's a difference in how a plane flies. I use knife edge as an example for this is the easiest way to picture the weight's effect. My only mono is the Laser and when placed in a knife edge the only input required is rudder, it will not fall off to one side. Biplanes are inherently different but still benefit from being balanced in this manner, just not noticeable in the same way.
Basically this is balancing the airframe in all axis and is beneficial in every attitude of flight. My piloting skill's are marginal at best but I have had skilled pilots fly my aircraft and comment on how well it flies, this is because of set up and balance.
I would imagine the like's of Jase and others at his level have this balance whether it was knowingly intentional or not, especially in IMAC and Pattern.

 

[WMcNabb]

Well, I actually do it and it really make's a difference in how a plane flies. I use knife edge as an example for this is the easiest way to picture the weight's effect. My only mono is the Laser and when placed in a knife edge the only input required is rudder, it will not fall off to one side. Biplanes are inherently different but still benefit from being balanced in this manner, just not noticeable in the same way.
Basically this is balancing the airframe in all axis and is beneficial in every attitude of flight. My piloting skill's are marginal at best but I have had skilled pilots fly my aircraft and comment on how well it flies, this is because of set up and balance.
I would imagine the like's of Jase and others at his level have this balance whether it was knowingly intentional or not, especially in IMAC and Pattern.

Now I’m extremely curious as to how you do this. Any chance for a tutorial?

 

[acerc]

In the pic the thick black line is the thrust line, note that most of the electronics would be below this line, along with the wing, l/g, and exhaust. Why would it not be bottom heavy when rotating sideways? Would this not make a number of maneuvers unbalanced at some point?

 

[Snoopy1]

I agree with you completely it should be balanced in all planes. If you only fly level and flat it makes no difference but as soon as the flys on a side it does. And yes I have corrected for this and when I did that plane could do I knife edge loop considerably easier.

 

[acerc]

Now I’m extremely curious as to how you do this. Any chance for a tutorial?

I use a brass tube that fits the prop shaft at about 12" long for the nose. Where the line meets the rudder (in the above pic for example) I make a dot, on a piece of tape of course. Then I place the brass tube on the table edge with the dot on the tail supported on a swivel point and don't let go. Usually I just have to raise/ elevate the batteries to get balanced, mounting electronic items above this line during assembly aids in this.

 

[acerc]

I agree with you completely it should be balanced in all planes. If you only fly level and flat it makes no difference but as soon as the flys on a side it does. And yes I have corrected for this and when I did that plane could do I knife edge loop considerably easier.

I got started doing this many years ago when I could not get a profile to knife edge without a lot of input. Another Pro-Bro told me about it.