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CypherKat wrote: ↑March 17th, 2023, 2:44 pm Second Place at States!!

Thanks everyone here for all the help and I've had a blast for the last 5 years. So many awesome memories I will never ever forget!

Good luck at States! The teams I coach will be at their Regionals tomorrow.

Hey, I think your question was buried under other posts--bringing it up here for other to see. I'll try to help as much as I can but the coaches will offer better advice.

epicSus wrote: ↑March 8th, 2023, 7:34 am Currently, it is stalling really bad at like 2 seconds and then diving down. We tried cracking and re-gluing the nose to get down thrust and turn (2 degrees left + 2 degrees down) like our other planes, but it made no difference. We did stab tilt (maybe 15-20 degrees) and it boosted the performance slightly (30 seconds) but still had the gist of stalling and diving.

Whoa, did you say 15-20 degrees? That's way too much--I think most people are using around 0-4 degrees. How are you calculating the tilt?

epicSus wrote: ↑March 8th, 2023, 7:34 am Visualization of our flight: It takes off, climbing (pretty well) for 2 SECONDS!!! Then it slows down A LOT and front wing height increases over back wing A LOT, then it falls. If it doesn't hit the floor the first time, it will continue swooping for 10 seconds.

Is the front wing height moving during the flight, or am I misinterpreting this? If so, make sure the wing posts fit snugly(not familiar with J&H's plane) in whatever holds them to the motor stick. You're getting severe stalling.

epicSus wrote: ↑March 8th, 2023, 7:34 am 1. Will increasing the height of the front wing (leading and trialing edge) by 0.5 cm have a profound effect? When assembling the plane, I made the front wing height higher for experimental reasons and can't figure out if this is making it stall.

Yes. Div C planes are ridiculously sensitive to incidence(angle of the wing). Instead of cracking the motorstick and regluing(adding extra weight, probably weakening the motorstick too), you should adjust the incidence by moving one wingpost up or down. Move either the front wingpost down, or the back wingpost up, until the "swooping" motion is gone. Like the coaches said in previous posts, try to get it to the point where you have just a little "swoop"(stall), and then lower the incidence so the plane flies with its nose up. Also, you will need to adjust both washin and incidence, as they both affect each other and your plane will likely not climb without washin.

epicSus wrote: ↑March 8th, 2023, 7:34 am 2. Should I apply washin or washout to make it stop stalling? I felt like by making the leading edge lower than the trialing edge should make it not lift so much and hopefully control the plane.

Washout is used on outdoor planes more often--wash-in will reduce any roll(one wing lower than the other) in flight and will have a slight effect on stall, but you should adjust incidence instead(not sure what washout does as I've never used it). That should get rid of the stall.

epicSus wrote: ↑March 8th, 2023, 7:34 am 3. I have tried using no shim as well, and still stalls and dives repeatedly, so if you know how to fix this, please let me know.
4. Should I try increasing the length of the front wing to maximize performance?
5. Should I sand down the fuselage a little to try evening out the weight?

3. The main way to fix stalling and diving is through adjusting your wingposts. The shim will not help as much as adjusting incidence
4. No. Most kit designs(I say most because Guru exists) are well-designed and should not need much modification to fly 2:00+.
5. No. You might sand too far and weaken it, but I doubt the weight comes from your motor stick. What glue are you using to attach the wing covering and assemble the plane? If you're using CA, use this: http://gryffinaero.com/models/ffpages/tips/cyaapp.html or a toothpick(After pouring a small puddle of glue out on something).

I'm going to attempt to elaborate on washin and incidence, but the coaches are better at explaining things like this over text. What I did for my plane was to adjust incidence until I saw a glide to the floor. It would roll to the left(right wingtip higher than the left), and I added washin to make both wings level during flight. Hopefully that makes a bit more sense.

Following up that last response by Cat

You also need to verify your CG. If too far aft, the plane will also stall (and be unstable). Adjusting incidence will not help if the plane is grossly tail-heavy. Verify the CG location relative to teh instructions/plans if a kit.

It would help to report all key parameters when asking for help. This includes CG location, incidence measurements, rubber size (preferably g/in, or loop length for a 2g motor), wash-in amount, torque (max and after unwind to launch torque), winds, etc.

Coach Chuck

Hi, so I competed at our regionals yesterday(1st place in Flight!), and now I’m looking for information on the states facility. Our coaches say that they’re not sure where Flight will be held at OSU, but they say that it’s been held in the French Field House, which is a large indoor stadium. I couldn’t find any exact numbers, but it’s definitely 40-50+ ft tall. With this new ceiling height, I want to get the most performance I can, but whenever I try to fly in our middle school gym(53ft including rafters and such), I can’t get a good descent and cruise whilst also getting my plane to climb up to take advantage of the height. Are there any more specific trimming tips for a tall ceiling?

randomdogonapc wrote: ↑March 19th, 2023, 11:47 am Hi, so I competed at our regionals yesterday(1st place in Flight!), and now I’m looking for information on the states facility. Our coaches say that they’re not sure where Flight will be held at OSU, but they say that it’s been held in the French Field House, which is a large indoor stadium. I couldn’t find any exact numbers, but it’s definitely 40-50+ ft tall. With this new ceiling height, I want to get the most performance I can, but whenever I try to fly in our middle school gym(53ft including rafters and such), I can’t get a good descent and cruise whilst also getting my plane to climb up to take advantage of the height. Are there any more specific trimming tips for a tall ceiling?

Random,

Are you saying that you do have a 53 ft flyable ceiling in your middle school? What do you mean by 53 ft including rafters?

If you are already practicing flying this height, what trim rubber and winding specs are you using and what flight times and flight character are you getting. The more details the better.

If you don’t have a high ceiling to practice in, the typical prep method would be partial motors.

Brian T

By “rafters and such” I meant the framework that you typically find in a gym, including basketball nets when they are up. I’m getting around 2:45 times right now, and my flights in that gym are usually 2:10 when I try and get it to climb to the max flyable height without getting stuck. In my flights in an average gym’s height, the plane will have a slow climb, a long cruise, and a pretty fast descent(still trying to optimize that). However, our best flights in this gym have a fast climb, achieving max height in the first 20 seconds, and then they cruise for about 2-3 circles before a long descent.

I’m using the same rubber that I mentioned a few posts ago. I wind to a pretty high launch torque(0.7in/oz). My incidence settings are in a normal to high range(LE is 1.6 cm above TE). This is what leads to the fast climb, and the pretty high incidence causes it to stall in the later portion of the flight. I just want to fix the lack of climb and the overall speed of my climb without affecting the max altitude that my plane hits.

randomdogonapc wrote: ↑March 19th, 2023, 1:30 pm By “rafters and such” I meant the framework that you typically find in a gym, including basketball nets when they are up. I’m getting around 2:45 times right now, and my flights in that gym are usually 2:10 when I try and get it to climb to the max flyable height without getting stuck. In my flights in an average gym’s height, the plane will have a slow climb, a long cruise, and a pretty fast descent(still trying to optimize that). However, our best flights in this gym have a fast climb, achieving max height in the first 20 seconds, and then they cruise for about 2-3 circles before a long descent.

I’m using the same rubber that I mentioned a few posts ago. I wind to a pretty high launch torque(0.7in/oz). My incidence settings are in a normal to high range(LE is 1.6 cm above TE). This is what leads to the fast climb, and the pretty high incidence causes it to stall in the later portion of the flight. I just want to fix the lack of climb and the overall speed of my climb without affecting the max altitude that my plane hits.

Sorry, should have been more specific in my question. Is the flyable ceiling in your middle school 53 ft? Can you share your flight log details? Remind us what kit you're using. video would be good.

1.6cm wing incidence is quite a bit.

You are a middle school competitive?

Brian T.

The flyable height in our gym is about 45-47 feet. I’ve gotten similar results with lower incidence due to less stalling in the descent, but in the end prioritized the high incidence because the rubber that we used at our competition yesterday was my partner’s and strangely snapped a lot more easily than my motors. I’m using this year’s FF kit. A good example of the flights that we’re getting is the video that I PM’d to you a few days ago, with a slower descent and less of a cruise. And yes, I am a Div B competitor.

randomdogonapc wrote: ↑March 19th, 2023, 1:30 pm By “rafters and such” I meant the framework that you typically find in a gym, including basketball nets when they are up. I’m getting around 2:45 times right now, and my flights in that gym are usually 2:10 when I try and get it to climb to the max flyable height without getting stuck. In my flights in an average gym’s height, the plane will have a slow climb, a long cruise, and a pretty fast descent(still trying to optimize that). However, our best flights in this gym have a fast climb, achieving max height in the first 20 seconds, and then they cruise for about 2-3 circles before a long descent.

I’m using the same rubber that I mentioned a few posts ago. I wind to a pretty high launch torque(0.7in/oz). My incidence settings are in a normal to high range(LE is 1.6 cm above TE). This is what leads to the fast climb, and the pretty high incidence causes it to stall in the later portion of the flight. I just want to fix the lack of climb and the overall speed of my climb without affecting the max altitude that my plane hits.

I agree with Coach Brian's statements, we need FAR MORE info to help point you in the right direction. Plane setup details, rubber winding and unwinding and torque details, density, etc. Getting to 2-3 minutes is the easy part and can be done with minimal information. Going to the next level requires detailed logs, minute adjustments, and lots of experimentation.

I will echo what Coach Brian said. 1.6cm incidence on the wing is MASSIVE. I would say this is indicative of a very nose-heavy plane. Generally you will want to be between 3 and 6mm of wing incidence, 0 stab on a B division plane this year. The range of incidence will correspond to a range of CG location (stability), and will depend on the air conditions (want more stable for rough air), touches (no-touch calm air can be less stable), etc. Less stable CAN mean more time aloft, but at the risk of quick undoing if you bump the ceiling or rough air.

Now, IF YOU HAVE THE PLANE OPTIMIZED for a certain ceiling height, then going to a higher ceiling will mean slightly thinner rubber for more winds, and then higher torque at launch (accomplished by fewer unwinds after winding to near breaking). Just how much to change your rubber will need experimentation. For each rubber size, find a launch torque that gets you to the ceiling, and then evaluate the turns remaining after landing. Too many, go to thicker rubber. Too few or running out, go thinner. But this requires that you get to the ceiling first. Getting to the ceiling (assuming your trim was already optimized) will require higher torque. Higher torque also rings in more possibilities of deflections, roll in, etc. You MAY need more wash in for higher torque, depending on the plane design and the trim settings.

As Coach mentioned, you can work with partial motors (for example half motor, with half spacer) to get an idea of the performance when testing under a low ceiling for application in a higher ceiling. Search partial motor or half motor in these forums from prior year, it has been covered extensively. We rarely use full motors at all in practice sessions, minimizing the risk of hitting the rafters even if our gym is similar in height to the competition gym.

Coach Chuck

Back again after another flight session! It was only one hour so I didn't get to fix much, though.
I'll link videos here when they finish uploading--restricted access to Coach Chuck and Coach Brian as of now.
Questions:
1) How do you tighten up your turn? I added some more stab tilt(2.66deg now) and decreased washin and rudder offset, and am seeing a very large circle that tightens up under high torque but loosens to at least 23+ feet when descending/cruising.
I don't want to add more stab tilt(3+deg seems rather extreme), and more rudder offset will make things worse judging from past adjustments. bjt4888, I did see some of the wing rib skew you mentioned previously, but after reducing washin, it skews to the left. Not sure how to adjust further--I originally thought less wash-in would help but I've had to decrease it to avoid right turn, to the point where it barely climbs.
2) How do you make the plane climb efficiently? On 0.26oz torque the plane climbs to around ~18ft and I feel like that's rather low... It actually might be 15, as I'm eyeballing. I've increased wing incidence to the maximum, along with washin(probably 1/16-1/18" right now)--any more washin and it begans to turn right... no washin and it dives. I'm also seeing a straight line and slight tilt to the right at the beginning of flights, and then a steep climb and turn into a left circle. I remember reading that this shows too much washin, but without washin the plane refuses to climb. Is there anything I can do to get rid of this?
I know what factors adjust these, but it seems like those settings are maxed out. It's just very strange behavior in comparison to previous planes... For 2), I suspect there may be some slight positive incidence to the stabilizer(tailboom joint might be crooked) but I can't confirm this at the moment. I don't think the motorstick is bending--It's relatively short, and I wasn't winding to high torque, either. I do recognize that there is instability at the end of the flight--I'll be fixing that in my next flight session, as tonight's was rather rushed.
Thanks!
Gosh I thought a second plane would be easier, but it seems like this one has even more problems than the previous.

EDIT: Videos processed! Ordered by duration(so flight 1) here on the forums is the shortest, flight 4) is the longest. Hope this isn't confusing, I'll rename the videos to help too)
1) The first flight. Barely stayed up--diameter is very large(See previous videos for size reference/estimation)
2) Added more power-0.2oz torque. Barely got off the floor, this was with new rubber too...
3) Ends by crashing into a box. No clue what torque was(I should probably start logging trimming flights..), but it's circling in an oval?? Very odd. Could be exaggerated circle shift I suppose? I'll check my joints again, just in case.
4) 0.26oz torque. Compared to my old plane(overweight by like 0.3g if I recall correctly...), it climbs less. Not sure how to fix this, and I'm afraid that the straight line it does in the beginning will be amplified when wound to higher torque, as I'm almost certain my states venue has a 25ft+ ceiling. I can't add more wash-in... If I add more incidence a) it gets to be rather extreme and b) it will cause the wing post to wing joint to snap.

Yikes. Huge improvement, so I'm pretty excited about that--it turns somewhat proper now, but the diameter is quite an issue...
https://drive.google.com/drive/u/0/fold ... 7Z3l76-IFM If you cannot access this, please let me know! Thanks again everyone