Wright Stuff C

[lechassin]

Xiangyu,

Here is info you wanted on offset wings, and preventing/managing unwanted wing warps:
https://www.youtube.com/watch?v=fqAXTjM ... e=youtu.be

Note that when I'm pointing out the offsets, I get it backwards: the 9/16" for left turns means the wings are offset to the left 9/16". Also please note without laughing too hard that at as one ages one needs reading glasses, and then as one ages more one needs to stack two pairs of reading glasses...

Intentional wing warping is so distasteful to me (some sort of psychological need to have things straight ) that someone else will have to post a how-to on that.

Your monoplane flies great, I'm impressed with the times. I still think a biplane is better, but I will confess you have seeded some doubt

[lechassin]

We spent the morning in another identical gym, and we flew the plane with 1/2" offset wings, only to the right and with mixed results.

On the plus side, the wings stay perfectly level throughout the entire flight and the launch/climb is a stable multi-lap affair. Sadly, in order to avoid hits, we need to back off a whopping 500 turns (from 5400) and launch at a paltry 0.2 in.oz with zero decalage (aft CG for level cruise). Any shim at all and we would hit the highest banner even at 0.2 in.oz. Then of course there is no recovery. Overall flight times are no better because we're giving up so many turns, so we did not launch at higher decalage/lower torque.

We did beat our previous no-touch 1'50' with a single 1'53" flight, using 3mm decalage, a conservative CG and 0.3 in.oz, keeping 5200 turns. Few knots remaining, and decent recovery from hits, but we had three climbs into a 25 foot banner. Considering the 10 foot recoveries, the plane would have climbed 50 feet unhindered. 0.4 in.oz still yields a stable climb, but much too fast and the flaring prop is obviously at its structural limit. In a blimp hanger I have no doubt we'd be over two minutes, but alas...

So today, we either had to embrace multiple hits or fly at suboptimal motor and airframe specs, only to get flight times in the range we've already achieved on our less efficient (banking) plane.

I think our prop is optimized for now. If I understand correctly, rubber that is thinner than our current 0.0625" is the next step, but we want to take care not to hurt cruise time too much. We're thinking 0.060", is that a good guess?.

[CrayolaCrayon]

Few knots remaining, and decent recovery from hits, but we had three climbs into a 25 foot banner. Considering the 10 foot recoveries, the plane would have climbed 50 feet unhindered. 0.4 in.oz still yields a stable climb, but much too fast and the flaring prop is obviously at its structural limit. In a blimp hanger I have no doubt we'd be over two minutes, but alas...

This was me all of last year; I was notorious for hitting the banner at my school; always hitting and recovering. I've found from experience that often times your time is almost the same or sometimes less when you fly in higher venues without the banner hits. It all depends on when you're hitting the banner. If you hit it near the end of your cruise, you don't have the power to recover, thus your time will be less. I'm unaware of what Illinois state's WS venue is like, but I've heard it is huge (not sure on this). If it is more than twice the height of your gym, preparing with half motors, maybe even quarter motors would be suitable; Coach Chuck can also attest to this.

You'll get the most improvement from proper trim, and getting the turns into the motor, but there is a line between having enough turns and being underpowered.

[coachchuckaahs]

Last year we exclusively tested on half rubber, especially for Nats where the lights were at 38 feet. This year with the very long rubber you may want to do that just to conserve rubber.

Touches are not bad, but you want enough stability to recover. We ended up touching 3 times on our winning flight at Nats last year. That was not the plan for first flight, but we got lift over the crowd which got us strongly into the lights. Recovery was nice, only a few feet dropped each time.

If you are running out of winds plus backing off, you probably need thinner rubber. Typically "best" when unwinds matches remaining turns or so. We have had years where we had to unwind under 0.2 oz-in with much thicker rubber. Yes, it hurts to unwind that much!

Coach Chuck

[lechassin]

Thanks for the response(s). I just ordered a 9 gram sample of 0.060", enough for 3 motors.

I figure the 1'53" flight, hits or not, shows our prop (but not the plane) is optimized for 0.0625". We only backed off 200 (5400 to 5200), and landed with less than a row of knots. I hope the thinner rubber will give a slower climb and similar cruise, but I think we're near the maximum that this design (and our skill set...) is capable of. It's disappointing because we'd really like to take advantage of the obvious increase in efficiency of the offset wings.

Our less efficient but completely dependable plane (with centered wings) always gets 1'45"+. I can only see doing better by winding more aggressively to a higher initial torque, but even then we'll only get a few more seconds at 2400 rpm . It might not be worth the risk of motor breakage in the 8 minute window.

[xiangyu]

For rule 5b, does anyone know if the 5% is applied to only that flight or the entire base score? (Like both official scores combined). If I do a practice flight for the 3 minute preflight period would that 5% bonus still apply to my official flights?

Xiangyu

[CrayolaCrayon]

For rule 5b, does anyone know if the 5% is applied to only that flight or the entire base score? (Like both official scores combined). If I do a practice flight for the 3 minute preflight period would that 5% bonus still apply to my official flights?

Xiangyu

After your two flights, those times should be added to make a score, then those bonuses should be applied at the end. That's what I think at least.

[coachchuckaahs]

Good point.

It does seem a bit ambiguous.

Base time: The single longest flight time
5% (3-minute) bonus is added to the BASE TIME, not the final score
10% (colored wing panel) is added to the "Flight Time" of the airplane with the panel painted. This would imply it applies to both flights if such panel is painted.
The reverse circle bonus says "...the flight times will be added together for the official score". This would almost imply that if you get the reverse bonus, the other bonuses don't count? (Only reference to official score).

I suspect they mean the 3-minute bonus applies to the one longest flight, the color bonus applies to all flights, and then add these together for the total is reverse bonus is used.

I think I'll put in a FAQ for clarification though. You might too, to make it Frequent.

Coach Chuck

[bjt4888]

Chuck,

Good idea to post in the FAQ regarding the bonuses.

Another possible indicator of how these work is to download the official scoring spreadsheet and enter sample data.

Brian T

[xiangyu]

Chuck,

Good idea to post in the FAQ regarding the bonuses.

Another possible indicator of how these work is to download the official scoring spreadsheet and enter sample data.

Brian T

Based on the sheet, the 5% bonus is applied to both flights base time combined. I'm assuming that launching a practice flight/just throwing it without the rubber band still qualifies for the 5% bonus?

Xiangyu