Flight B/C

[Astronomyguy]

Thoughts on using a better box for practice sessions? I've been using my competition box to hold my plane until now, but the plane barely fits and the winglets are often bent in. This has recently caused a lot of damage and I have had to make a new wing as a result. I'm thinking of using a larger plastic box to hold the plane on a daily basis instead of the competition one. Do any of you do the same?

[pumptato-cat]

Yep, I use a cardboard box taped shut with trash bags as padding. I'm hoping for a better box if I go to states after regionals, but for now, the cardboard will have to do. It's lasted for months, by the way--through a ton of abuse.. so if you need something in a pinch that'll do just fine.
I have a separate impound box and the carbon fiber edges bend slightly when being placed in the box, so watch out for any bending (technically a rules violation).
Also THANK YOU astronomyguy!! So many people ask questions and the coaches are constantly helping everyone here. It'd be easier on them if we provided the necessary information without being asked(I am guilty of this too ).

[bjt4888]

Thoughts on using a better box for practice sessions? I've been using my competition box to hold my plane until now, but the plane barely fits and the winglets are often bent in. This has recently caused a lot of damage and I have had to make a new wing as a result. I'm thinking of using a larger plastic box to hold the plane on a daily basis instead of the competition one. Do any of you do the same?

Astronomy,

We do not use the measurement box as a transport box. We disassemble the airplane and set in the measurement box and then place the measurement box in a locking lid Sterilite brand plastic storage box. They make a storage box that is a couple of inches bigger than the measurement box and fits perfectly. We do this box within a box in order to prevent damage to the measurement box as they are carried on the bus and through the the rain and snow as we walk to and from flying venues and travel to Invitational competitions.

We never leave the airplane fully assembled in the tight fitting measurement box. As you have found, this is a recipe for damage.

Brian T

[coachchuckaahs]

Thoughts on using a better box for practice sessions? I've been using my competition box to hold my plane until now, but the plane barely fits and the winglets are often bent in. This has recently caused a lot of damage and I have had to make a new wing as a result. I'm thinking of using a larger plastic box to hold the plane on a daily basis instead of the competition one. Do any of you do the same?

We do not store the plane in the measurement box. This is particularly important if your plane fits in on the diagonal, as it loads up the wing. It is also a tight fit in and out, potentially leading to damage.

Our "measurement" box also includes a pair of poly foam (like computer stuff comes in) "stands" hot melt glued to the bottom. the stands are perhaps 1" x 2", height as needed. These have a slot cut diagonally at the top to hold the plane, and are glued in carefully after adjusting with the plane, to get minimal touching of the box by the plane.

For transport, we use a large LOCKING LID Sterite box, such as https://www.walmart.com/ip/Sterilite-10 ... d/46001911, with similar stands to hold two planes. We prefer to keep the planes fully assembled. While we have careful measurements of decalage, this year's planes are sensitive to trim adjustments, so we prefer to not disassemble. These boxes give planty of room to safely handle the plane during practice sessions. This is NOT a good way to transport if you need to go by air!

Coach Chuck

[Astronomyguy]

Thanks to Coach Chuck, Caoch Brain, and pumptato for the responses concerning the box. I'm using a Sterilite box to carry the plane around now. I probably won't be encasing my measurement box in another box because the only tournament left for me is regionals (unless our B team beats the A team), which won't require much traveling.

Updates on my plane:

I haven't flown in the past week because I've been waiting for material shipments for a new wing. I assembled the wing yesterday and it ended up much cleaner and tighter with the mylar than the old one while weighing ~0.15 g lighter without the extra glue, scotch tape, and mylar patches.

One thing I noted while redoing the wing was that the wing warp was less than it was before (0.5 cm as opposed to 1.5). My understanding of wing warp is that it allows for more lift on the inner edge of the plane, which counteracts the high roll at launch torque. I know that its effect is felt mostly in the launch/climb stage of the flight, while the circle size is determined mainly by the horizontal stabilizer after the plane levels out. However, I cannot help but visualize the inner edge of the wing providing ever so slightly more lift than the outer edge even after the climb stage, which would cause the circle to get larger as the flight went on (a problem that I have had for a while).

With that in mind, I decided to leave the wing warp as it was, knowing that I could counteract high roll with more washin or with shims.

I tested this morning and the plane was definitely tilted toward the inside edge by quite a bit. (I'll PM the videos). This didn't seem to have a detrimental effect on the flight, as the circle was definitely more stable than before, but I'm sure that the plane would conserve more energy if it were to fly in a more level state. Using our torque meter for the first time, we made a rough torque estimate (0.5 oz/in, max torque reached was ~0.7 oz/in) and it flew pretty well. The recorded times were pretty much at 2 minutes but can probably be improved to 2:30 or so with better torque approximation, winding (we only pushed to 90 winds today), and environment. The last flight had at least 10 seconds cut off of it because the gym was being set up for the day and the doors were open and blowing air.

Here are some questions I have:

1. What does adjusting wing warp do compared to adjusting the washin?
2. Should I be adjusting the wing warp with shims in between flights? It's something discussed in the Fredomflight manual but not on these forums.
3. Any general comments about my flight?

[coachchuckaahs]

Astronomy:

I am not sure what you are indicating as "wing warp" vs "wash in". Wash in is a warp or twist of the wing that results in the left tip having more incidence than the right tip. Wing wash is used to control the initial climb. If the plane badly tilts inward at high torque (launch), or even dives to the ground, then you may want some wing wash. HOWEVER, wing wash is a detriment later in the flight, as it presents drag and recues your duration. Personally, I would accept some rolling in, as long as it is climbing, rather than have excessive wing wash. If adding torque causes LESS altitude, or cannot make it to the ceiling even as the highest torques, then I would add some wing wash. These planes are tending to climb too fast anyway, so if the first circle or two race without climbing, but do not dive, and can be repeated safely, that is time on the clock! But if it never gets to climbing, and you have properly wound and have torque in the 0.8 range (that is higher than I recommend, but if it won't respond even at this high level), then I think wing warp/wash is beneficial. The 2019 plane, as bad as it was, strongly benefitted from wing wash, with small amounts turning racing (speed) into climbing. We are typically seeing 0.4 to 0.6 torque in a typical (25-30 foot) facility

A few other points in reviewing your flights:
1. When you video the flight, please start at the launch. This is a critical part of your flight that is missed in most of your videos. Wing wash should NOT be used to correct issues in letdown!
2. Altitude is EVERYTHING. If you are not getting to the goal altitude (girders in your gym, or height of girders for the event you are preparing for) consistently, you need to make adjustments to that before comparing flight times. Flight times at different peak altitude are not comparable at all. If a change in trim changes peak altitude, change torque or other trim elements to restore altitude before comparing time. Be sure logs include estimated or measured altitude. If you know the gym height, you can easily estimate distance from ceiling. In addition, note that baskets are at 10 feet. We also record the first lap altitude as this impacts many trim parameters.
3. The common configuration this year of a flat wing with tip plates does appear (see posts by coach Brian) to need a notable amount of wash in. Moreso in C division than B. However, you want as little as you can get away with, because it impacts later flight duration
4.
5. Your logs do not show max torque in winding. However, you are showing very slight (a few rubber winds) unwinds ot get to your launch torque. This leads me to conclude you are not winding hard, and therefore you are essentially winding UP to the launch torque or barely above it, rather than winding hard and then backing off. You should probably see 50 to several hundred unwinds. Your max torque in winding should be 1.2 to 1.6 oz-in with the sizes of rubber we are using this year. DO NOT accomplish this by tightening up AFTER walk-in. You can reach torque quickly this way, but it does not pack in more winds, and it is a peak on a very small part of the rubber. You should reach at least 1/2 of your goal torque (0.6 or so) at full stretch (6-8x) before starting to walk in. When torque starts to sharply go up, that is your signal to start walking in. The torque should at least stay level if not increasing in the first half of walk-in, and then ramp up more sharply as you complete the second half. The torque noted at full stretch (0.6?) should be about doubled to get your final max torque. The winds at full stretch will be 50% to 60% of your total winds. At halfway in you may be at 80% winds and 3/4 of your torque max.

I also note that in your shorter flight in the atruim, the plane seems to be fighting, like part of it wants to circle and another part does not. It appears you may have very little tail tilt. However your later flights do not appear to have changed this, and yet the plane is not fighting visibly. It is possible you had a warp or drag issue on your older wing and that was resolved with a new wing. You need to balance rudder offset, tail tilt, left thrust, and potentially wing warp to work in concert. Forcing the plane to circle with one parameter out of balance will be detrimental to long duration.

As far as your questions, I am not sure what you are differentiating between wing wash and warp. They both mean the same to me. You should record your estimated wing wash. It shoudl eb adjusted to address specific concerns (climb vs racing), but not necessarily every flight.

Coach Chuck

[randomdogonapc]

Question for Coach Chuck. In your video about making propellers, you used a 3d printed pitch gauge. I found it on thingiverse and can print it next week, but would you know what hardware is necessary for assembling it?

[pumptato-cat]

randomdogonapc, I have the exact same gauge printing right now. There is a list of screws and bits required in the Thingiverse description.
Astronomyguy, I have an FF plane and it needs a ton of washin to climb. If there is not enough washin, even ~0.9oz torque will not make the plane climb well(In my case, increased torque from 0.3 to 0.95 showed very small change in altitude.
Oh, also--Thank you Coach Brian and Coach Chuck!!! The torque meter's been fixed. The wire hook was slipping. Everything looks good now )

[coachchuckaahs]

Question for Coach Chuck. In your video about making propellers, you used a 3d printed pitch gauge. I found it on thingiverse and can print it next week, but would you know what hardware is necessary for assembling it?

The hardware is listed in the thingyverse description.

Required parts:
(4) #8 x 1/2" flat head wood screws for stands to base
(2) #4 x 3/8 pan head sheet metal screws for protractor pivot and wire clamp
0.015 to 0.020 wire to make clamp for prop shaft
(1) #6 x 3/4" machine screw for protractor clamp, screw in from rear
(1) #6 knurled nut or wing nut (not shown) for protractor clamp
Sharpie for highlighting protractor scale and pitch chart (I used silver on black, and black on grey)

Be sure not to over-tighten the screws that hold the stands to the base.

I do have a revised prop stand end for those using a Ikara prop button instead of a wire prop shaft. I'll try to add that later, but if you need it PM me an email address and I will forward it to you.

On later prints, rather than highlighting numbers with a sharpie I did a color change of the filament.

https://www.thingiverse.com/thing:4319685

Coach Chuck

PS: Ikara prop stand was added! Re-download as needed. If you use Ikara prop button, you will need the Ikara prop stand, and will not need the regular prop stand, the wire clamp, nor the wire.

[pumptato-cat]

Hey all, how do you cover parts with mylar? I'm using the FF kit method and just managed to spray glue an entire wing to a newspaper. I got it off and now everything is warped. Any better ways to do this? I'm so frustrated..

Also, a tip of the stabilizer has a warp upwards. Should I be concerned?