Flight B/C

[randomdogonapc]

When I cover my lifting surfaces, I use the method shown in Joshua Finn’s videos, where you go outside, hold the skeleton of your lifting surface by the corner, and spray it. Then I bring it inside and lay it on a newspaper glue side up and lower the covering frame onto the skeleton. If this doesn’t make sense, watch the Stinger build video on Joshua’s channel.

[coachchuckaahs]

When I cover my lifting surfaces, I use the method shown in Joshua Finn’s videos, where you go outside, hold the skeleton of your lifting surface by the corner, and spray it. Then I bring it inside and lay it on a newspaper glue side up and lower the covering frame onto the skeleton. If this doesn’t make sense, watch the Stinger build video on Joshua’s channel.

I believe Coach Brian has a video on covering, or we did a P-18 build and the covering operation was included.

We ball the covering up TIGHTLY twice to make uniform micro wrinkles. Then put it on a frame with Chapstick or Vaseline. Spray the frame VERY LIGHTLY with 3M77, preferably outdoors. We use a cardboard box, and fold a ridge in a sheet of paper to hold the frame off the surface. Basically make 3 folds about 3/4" apart to make a mountain on an otherwise flat piece of paper.

After spraying, turn over the wing in your hand, carefully center it over the covering on the frame, and lower it on. Once it touches it sticks! gently rub along all edges to be sure it touches down.

The micro wrinkles make the covering slightly springy so that it does not induce warps in the model. You do not want it tight as a drum.

The P-18 build, which is similar to SO (7.5g) is at https://youtu.be/my9_D5M1D3c, and the covering is at 1:14:40. Looks like the P-18 was covered with Veggie Bag material, and no frame was used. With Ultrafilm, you want to use a frame. See Josh's video. Only difference is he lifts the frame onto the wing instead of vice versa.

Coach Chuck

[pumptato-cat]

Thanks!
I basically did the exact same thing except I covered all pieces at once(because the FF kit only provides enough mylar to do covering in groups. The basswood frame I stretch covering across is too large to do pieces one-by-one). I sprayed them with glue outdoors(48f, not sure if temperature matters) on a piece of newspaper taped down to the floor. I did two passes and waited for around 20sec, and then put the basswood frame with the mylar over all pieces being covered(tips, stab, wing). After that I just pushed the mylar onto the frame with my fingers, but the middle sagged in the wing somehow and the entire wing got glued to a newspaper. I would do the mountain trick(that is so smart ) but I'd have to cover everything one by one and I don't think I can do that...
I guess part of it is that I get anxious that the glue will dry before I put the covering on(in the FF instructions, it says to "not waste time" placing the mylar on the pieces, to ensure "best adhesion"). I'mhonestly just mad my covering came out worse than my first plane. Maybe it was a combination of that, along with the garage floor being bumpy. I taped the newspaper down, but it still wasn't flat.

[coachchuckaahs]

Cat

You do not want the covering anywhere near where you sprayed. Spray the frame, then move it indoors. You can place multiple prices face down into the covering in the frame. If you prefer, you can put the price have up and lower the frame into it. You can then lift the frame and move to your next piece to get them all on one frame. Or arrange them all and lower the frame one time.

Coach Chuck

[jander14indoor]

Thanks!
I basically did the exact same thing except I covered all pieces at once(because the FF kit only provides enough mylar to do covering in groups. The basswood frame I stretch covering across is too large to do pieces one-by-one). I sprayed them with glue outdoors(48f, not sure if temperature matters) on a piece of newspaper taped down to the floor. I did two passes and waited for around 20sec, and then put the basswood frame with the mylar over all pieces being covered(tips, stab, wing). After that I just pushed the mylar onto the frame with my fingers, but the middle sagged in the wing somehow and the entire wing got glued to a newspaper. I would do the mountain trick(that is so smart ) but I'd have to cover everything one by one and I don't think I can do that...
I guess part of it is that I get anxious that the glue will dry before I put the covering on(in the FF instructions, it says to "not waste time" placing the mylar on the pieces, to ensure "best adhesion"). I'mhonestly just mad my covering came out worse than my first plane. Maybe it was a combination of that, along with the garage floor being bumpy. I taped the newspaper down, but it still wasn't flat.

OH MY, yes, as Coach Chuck said, move the frame from where you sprayed it! Since you attach the covering to the frame away from where you sprayed it, you can do it on a smooth surface, like a table. I use a soft brush to spread out the covering (after it has been wrinkled) evenly and get out wrinkles. Then attach to a covering frame, or just drop the wing frame on the covering.

As to "not waste time" don't worry too much on that. I typically prep my covering, take the wing/stab/whatever frame outside (I live in MI, it can be WAY colder). Apply spray glue (I've laid the frame on grass, folded paper, snow now and then), come back inside and attach film. I don't rush, but I don't read a novel either. Basically walk outside, spray it, walk back inside, cover.

Jeff Anderson
Livonia, MI

[jander14indoor]

Unexpectedly (the scheduled ES didn't show), I got to run the University of Michigan Invitational, Flight B this weekend. Results:
Top Team 3:20ish
Second just short of 3 minutes
Two teams at 2:30 or so
Four teams around 2 minutes
This is out of 27 teams total.

I didn't get the div C times.

Tiering for oversize boxes. I used a very precisely built gage that I'll use at regionals, Mi State and Nationals. I only tiered 5 teams for oversize boxes, and talked to many teams who had cut down boxes from failing at previous invitationals. The best times were not in boxes that pushed the limits, they were pretty clearly OK in the gage, except one. Seems teams are getting the idea.

Jeff Anderson
Livonia, MI

[danxmemes]

I have another question, about rubber this time.

1) how do I adjust my propeller/rubber setup so that I am able to land with the least number of winds possible?

2) What is the process of adjusting to thinner rubber with the same propeller? I know that some teams are using less than 3/32, but with the standard propeller. Is it something to do with the overall wings and design?

3) is flared props better? I have tried them but I end up landing with a bunch of rubber left, and less time left, but I would like to figure out how to get flared props to work

4) not as much to do about rubber, but I notice my plane vibrates during flight, especially so during takeoff and high torques, what causes this and how can I fix it?

5) Lastly, what are everyone else getting on their 3/32 rubber winds? I get around 1650 maximum at .5 inch ounces torque. I have to wind to 1800 and wind down for the torque. Otherwise (even in high ceilings) my plane's stab starts curving and the entire plane crashes to the ground. Should I be able to get more winds if I stretch longer and stay out longer? and how can I not make the tail bend like that and have the plane dive?

Thanks in advance!

[BrianZ]

1) how do I adjust my propeller/rubber setup so that I am able to land with the least number of winds possible?

If you are landing with many winds, and everything else about your fight is dialed in, you can decrease the pitch of the propeller or use thicker rubber.

2) What is the process of adjusting to thinner rubber with the same propeller? I know that some teams are using less than 3/32, but with the standard propeller. Is it something to do with the overall wings and design?

The process is just trial and error, and then make corrections. Yes the drag induced by your wings and the amount of lift your wings produce will be factors in how thick your rubber needs to be and the pitch of your prop.

3) is flared props better? I have tried them but I end up landing with a bunch of rubber left, and less time left, but I would like to figure out how to get flared props to work

I have never made a successful flaring propeller. I personally feel like that's a skill to master after my flights have been dialed in perfectly with non-flaring propellers. It's just one more variable to deal with, and although it's a valuable skill, I consider it somewhat advanced.

4) not as much to do about rubber, but I notice my plane vibrates during flight, especially so during takeoff and high torques, what causes this and how can I fix it?

If your propeller is balanced, the most likely culprit is the rubber climbing up the motor hook. A reverse S hook is supposed to fix that, but I've never used one. I just try to make sure the motor o-ring isn't climbing up the hook before I launch it.

5) Lastly, what are everyone else getting on their 3/32 rubber winds? I get around 1650 maximum at .5 inch ounces torque. I have to wind to 1800 and wind down for the torque. Otherwise (even in high ceilings) my plane's stab starts curving and the entire plane crashes to the ground. Should I be able to get more winds if I stretch longer and stay out longer? and how can I not make the tail bend like that and have the plane dive?

I can't answer this as I don't count winds. I go strictly off of torque. I know many people count winds, but I can't figure out what I'm supposed to do with that data. I guess it would tell you the state of your rubber, like if it's getting worn out and taking more winds to get to the same torque, but for competition we only fly with rubber that's been wound and unwound twice. When you say your stab is curving, what do you mean? Is your fuselage bending under the tension of the wound rubber? That will reduce decalage if your fuselage is flexing, and could cause a dive under high torque.

[pumptato-cat]

Does your plane have a long motor stick? If so, it's bending under the high torque you're winding to(0.5oz, right? that's pretty high. I wind to ~0.25oz to get to 23ft). If you look at this year's Div C FF plane, you'll see a kevlar truss with a balsa support on the plane. That is to help with the long motor stick's flexing and prevent the stabilizer's angle from changing, like BrianZ said above.

[pumptato-cat]

For those of you that have been to tournaments: I have two planes, an impound box, and a toolbox to carry by myself after impound. Since the 10-minute flight period starts as soon as the ES finishes measuring the motors, would you guys recommend disassembling the plane and carrying it? I'm worried about losing time, because I'll likely need the full 10-minute period. I'm also probably going to have to take two trips from the impound table to carry everything so I'm pretty anxious. For those also flying solo, any ideas? Is it just: pile stuff in your arms and hope that nothing falls?