Flight B/C

[jander14indoor]

Recommendation to experienced flyers who act as ES at invitationals. I have found it useful to offer a mini-clinic at the end of flying. Frequently there is a waiting period after flying while scores are compiled and students have little to do. Work with the Tournament Director to get it announced/advertised.
The nice thing about these mini-clinics is you are working with teams who mostly have attempted to build something to fly. Great way to get help them understand where their planes might need improvement, how to get started trimming, and so on. I am frequently able to help teams who have OK planes move from dives to at least some climb and duration. I then see even more improvement when I go to Regionals and states and supervise.

Jeff Anderson
Livonia, MI

[pumptato-cat]

Thanks jgrischow1!
I'm building my second plane soon, because I don't have anywhere to fly for a while and my first plane is overweight and beat up.
It's a stock FF plane, but I don't like the way the stab is attached, and want to be able to adjust the stab tilt to control circle radius. I was thinking of just making a tailboom, similar to the J&H Stinger. Is there a better way to adjust circle radius rather than just depending on stab tilt? And will the shorter motor stick length(and correspondingly, the shorter distance between the prop and the rear rubber hook) affect flight? I'm not sure if modifying a kit is the best, because I don't have a lot of experience in this event, but I'm willing to give it a go. Hopefully this works out!

[randomdogonapc]

I’m obviously not an expert, but I know that on the Stingers this year they have small cuts in the vertical stabilizers so that you can bend the top 1/4 of the vertical stabilizers to act as a rudder setting. You might want to mimic that on your second plane, but doing so will require you to have full balsa vertical stabilizers.

[bjt4888]

Thanks jgrischow1!
I'm building my second plane soon, because I don't have anywhere to fly for a while and my first plane is overweight and beat up.
It's a stock FF plane, but I don't like the way the stab is attached, and want to be able to adjust the stab tilt to control circle radius. I was thinking of just making a tailboom, similar to the J&H Stinger. Is there a better way to adjust circle radius rather than just depending on stab tilt? And will the shorter motor stick length(and correspondingly, the shorter distance between the prop and the rear rubber hook) affect flight? I'm not sure if modifying a kit is the best, because I don't have a lot of experience in this event, but I'm willing to give it a go. Hopefully this works out!

Cat,

Good job building again to improve.

Stabilizer tilt, and rudder offset (or tailboom side-to-side angle) are the typical adjustments to control circle radius. Although, as you already know, left wing washin and center of gravity location affect circle size too.

The design that my students use has a tailboom for two reasons, it makes the aft end of the airplane lighter and makes rudder and stabilizer adjustment pretty easy. A lighter tail allows the wing to be mounted further forward which extends the tail moment arm and improves pitch stability. We use an 10.5" fuselage stick (3/16"x3/8") with a 4" tailboom (1/8"x1/4" tapered to 1/8" square). The fuselage wood we use us light (6 lb cu ft or less) to give us a 1.0 - 1.25 gram fuselage (plus nosebearing and rearhook). The tailboom for our airplanes is between .12 and .15 grams (also 6 lb cu ft balsa). A shorter motor stick does not affect flight except to improve pitch stability (see above). You need to be a little more careful to follow good motor winding procedures if the motor is very much longer than the hook to hook distance on the motor stick. I explain this in the rubber winding video I attached on page one of this forum thread.

When deciding how long to make your fuselage, keep in mind that if you would like to try a flaring propeller this propeller type projects forward more than the symmetrical kit propellers. Our flaring prop projects forward a total of 1.125" (including the Harlan prop hanger). The symmetrical kit propeller projects forward .625". You just want to be sure that your airplane with its new fuselage fits into your box.

Have fun,

Brian T

[coachchuckaahs]

Recommendation to experienced flyers who act as ES at invitationals. I have found it useful to offer a mini-clinic at the end of flying. Frequently there is a waiting period after flying while scores are compiled and students have little to do. Work with the Tournament Director to get it announced/advertised.
The nice thing about these mini-clinics is you are working with teams who mostly have attempted to build something to fly. Great way to get help them understand where their planes might need improvement, how to get started trimming, and so on. I am frequently able to help teams who have OK planes move from dives to at least some climb and duration. I then see even more improvement when I go to Regionals and states and supervise.

Jeff Anderson
Livonia, MI

We have seen the same. The Austin TX invite is very early in the year, and we have now had two successful all-day seminars. The first was AFTER the event (Sunday), the second BEFORE (Friday). While doing so before may get messy (coaching before the event), it is not a huge issue for early invitationals, and it was very well received. We not only help the kids improve their trim and winding, we demonstrate AMA planes from gliders to heli's to F1D, and potentially gain recruits for next generation flying. We have several from ATX that are planning to tryout for the Junior Team this summer.

This is an all day experience in patience, but you WILL come away with a smile, as will the students.

Coach Chuck

[bjt4888]

Thanks jgrischow1!
I'm building my second plane soon, because I don't have anywhere to fly for a while and my first plane is overweight and beat up.
It's a stock FF plane, but I don't like the way the stab is attached, and want to be able to adjust the stab tilt to control circle radius. I was thinking of just making a tailboom, similar to the J&H Stinger. Is there a better way to adjust circle radius rather than just depending on stab tilt? And will the shorter motor stick length(and correspondingly, the shorter distance between the prop and the rear rubber hook) affect flight? I'm not sure if modifying a kit is the best, because I don't have a lot of experience in this event, but I'm willing to give it a go. Hopefully this works out!

One more thought. If you want the same length fuselage as the stock FF kit, the motor stick could be 11.375” with a 4” tailboom. This motor stick is plenty long enough as the longest motors that most teams are using on this airplane is around 15.5”.

Brian T

[pumptato-cat]

Thank you so much!!! I'll start building-hopefully everything goes okay. I'll try to use the j&h TB attachment because I honestly have no clue how else to do it...
Maybe this isn't the best choice but oh well, hopefully I learn something!
I only have sheet balsa in the "light-medium" density from specializedbalsa.com(leftovers from Bridge last season, I think 1/20"-1/8" is what I currently have), but I'll give it a go and see what happens.

[bjt4888]

Thank you so much!!! I'll start building-hopefully everything goes okay. I'll try to use the j&h TB attachment because I honestly have no clue how else to do it...
Maybe this isn't the best choice but oh well, hopefully I learn something!
I only have sheet balsa in the "light-medium" density from specializedbalsa.com(leftovers from Bridge last season, I think 1/20"-1/8" is what I currently have), but I'll give it a go and see what happens.

Cat,

There’s a picture in my Google drive folder that shows the tailboom attached to the fuselage. If your tailboom is tapered towards the tip (recommended) use a simple jig to be sure that the top surface of the boom is parallel to (or about 0.6 degrees angled up) relative to the top surface of the motor stick. Also, you can angle the tailboom a couple degrees for left turn in this jig too.

Our jig is just a piece of foam board with a sheet of graph paper on it and a sheet of wax paper over the graph paper with pin blocks positioned to hold the fuselage and shims to hold the tailboom angle as it is glued to the fuselage.

Brian T

[Astronomyguy]

I've read every post in the Flight B/C thread for this year and am excited to put some dedication into my plane in the next few months. Thank you to all the coaches and students that have contributed so far; I have learned so much just from reading your posts.

A little background on who I am:

I'm currently a sophomore, and this is my second year competing in Science Olympiad. My school has had a lock on the state competition for the past couple of years: I think we're on a 4 or 5-year Nationals streak. Last year was my first year in Science Olympiad, and I did it pretty much just for the Astronomy event (hence my name). Although Division B was available for me in middle school, I never tried to join it. In tryouts, I did pretty abysmally in everything I tried out for except Astronomy (I placed first in the school), so I was placed onto the B team (the worse of the two teams) and filled into 2 events that I did not try out for: Wright Stuff and Bridge. Build events aren't very strong in my school (and also our general area of the country), and I myself wasn't very keen to fill in the gap as a freshman. Our school is mostly a test-event school. Luckily, my partner and close friend had already bought a kit from FFM and was excited to build it (I think he did Gliders in Division B). We met often and had the plane built in winter. However, to say that we were beginners was an understatement: We broke our plane multiple times testing it outside in the wind and had zero idea on how to trim it (we had to look over the flight tips in the FFM manual for a couple of minutes each time we wanted to adjust). We had better success after testing the plane in the school gym with the kids in Wright Stuff on the A team. They had built and perfected their plane over many years, climbing a steep learning curve without ever using a kit (they've told me that their first plane wasn't made of balsa and weighed a whopping 24 grams). With times of 90-100 seconds, they easily dominated local invitationals, Regionals, and States by a comfortable margin. They gave us an old 5:1 winder and we used a lot of their tools. As for us, we never flew in competition until Regionals because our plane kept breaking (thank god Wright Stuff was an exhibition event for the longest time). At regionals, my partner and I managed to snag 1st place with a time of ~35 seconds, 400 winds on the rubber, and a huge stall after climbing. Our A team would have doubled our time if their plane didn't break after hitting the rafters (hence the 400 winds, we were extremely cautious about the 30 ft + ceiling). A and B teams placed 1st and 2nd in regionals respectively (by a long shot), but you're only allowed to send one team to states so the A team moved on. They scored 1st in states with 1:33 and 29th at Nationals. If it weren't for my partner and my mentor, I probably wouldn't be writing this post right now.

Fast forward to this year. Like last year, I'm on the B team for the school, and I am once again competing in Flight (formerly Wright Stuff). I'm mildly infuriated with my placement and want to prove that I am worthy of the A team, as there is a chance that I might be moved up if I do well. I had my plane constructed (from FFM) in time for the first invitational but did not test it beforehand. Our first flight was the trim flight within our 10-minute timespan. After launching, the propeller hook immediately came off, and since we left our toolbox on the sidelines, we had to vacate the floor (and our official flight) to repair the plane. Oh well, at least Flight was exhibitioned.

We started a flight log shortly afterward and started practicing in the gym every morning for two weeks to prepare for the next invitational (except for one particularly tough day during midterms week). Parameters consisted of the required ones plus Flight Notes and Changelog. We had a rough start and wouldn't get the plane to climb because it was always rolling in too much, but I fixed that when I found out that the wing was tilted ~5 degrees on the left side and the stabilizer even more on the right side. I had them reglued and the plane started climbing. I added 2 CF wing posts on the right side (like last year's design) to control the right wing. The finished weight of the plane was ~7.75 g (you can probably get it down to 7.5 with better gluing technique), so we could afford to make addons. The next big hurdle was that the plane kept stalling and losing a majority of its height after the climb stage, which limited flight times to around 50 seconds. We could never get the plane to cruise and climb on the same flight, and that was probably because we thought that moving the CG forward meant moving the wing forward. At one point the front wing post was only an inch behind the front of the motor stick. We realized this around 2 days before the Carnegie Mellon Invitational. That was also when we learned that we had to trim for a 4-meter ceiling, due to miscommunications with the club board. We had one day of testing left, so I made a 1/3 motor because I thought that you needed smaller motors to simulate a lower ceiling (I was wrong). In anticipation of my wrongness, I didn't attach the hook too tightly so I ended up removing it and using the regular rubber. The session ended with the plane crashing into the basketball hoop and the winglets breaking.

At the tournament (2 days ago from the time of writing) I tested the plane during my 3 spare blocks. The entire tournament I was basically either in my events or testing the plane; I had only 1 hour of free time between arriving and the last block when I was able to eat. The night before, I found this forum and began to read the posts. That was when I learned to trim properly, the importance of getting your rubber and propeller right, etc. The Flight supervisor was very nice and gave us from check-in until the end of the 7th block to get our official flights in (basically the whole day instead of the 10 minutes in the rulebook). I didn't know this and checked in at the beginning of my registered block. The plane weighed 8.04 grams with ballast included, and the rubber 1.89 (could be optimized). We didn't have any tools besides our 15:1 winder and other stuff I had from my house, and we looked on in envy at the other teams who had funding from the high school, armed with torque meters, glue accelerators, and the such. In previous testing blocks, our plane was flying around 40-50 seconds (on par with the top teams) but still had the stalling problem mentioned before. I read a forum post about moving the CG back 1/8 of an inch each time after testing, and that probably saved the event. In combination with that, I also experimented with adjusting the front wing post, propeller pitch (eyeballed, did not have a pitch gauge), and clay ballast on the wings to modify the circle size. I also watched the A team fly their J&H kit plane to 51 seconds. They also had another self-designed plane, but they had difficulty trimming that one to fly in low ceilings. With around 10 minutes left in my last free block, I hit a golden trim and my plane flew 1:23, hitting a trash can at the end. Interestingly, the plane never climbed more than a foot or two from its launch height but had a great cruise and descent with barely any stalling or imperfection. It probably would've neared 1:30 if it did not crash, with a peak altitude of maybe 6-7 feet. This was my first official flight and the one that would clinch first place by 25-30 seconds. I still had a second official flight left, so I trimmed the plane to have a wider circle and to climb more. It climbed to the ceiling and lost around 3 feet after a hit (I think that's pretty good stability), but the descent was way faster than my 1:23 because it was porpoising and losing a lot of energy to stall. I have a video of this flight and the configuration of the plane is in my flight log, which I will attach below this post (Making it public for now but might hide it once I get better). I did not record in the flight log for any of my test flights or the first official flight because of time constraints (also forgot my computer), but I was able to record stuff on the plane in configuration for the second official flight after arriving back home. My goal is to do extremely well in all of my events so that I can be moved up to A team and attend states/nats this year (and even if I'm not, the B team is really rocking it, we could beat A team if we work hard enough).

tl;dr Basically how I got to this point and how I got 1st place at my last invitational

Here are some questions I have:

1. After many rips and vert. stab/winglet breaks, the quality of the mylar covering has decreased dramatically. the right cell of the wing and the entire horizontal stabilizer have sagging mylar. For rips, I have resorted to using scotch tape to fix them, which increases mass but I don't think my plane is overweight. I might redo the entire wing and HS if needed from the parts of the second plane in the kit.

2. How much is overweight? How close to 8 grams should you be, and if you're already over, would it be ok to add a little more ballast or glue?

3. If I do the HS again, I might make it adjustable using the same balsa-straw fitting used on the wing. Thoughts? I've heard that there's a specific coupling of angles between the HS and wing that works the best. Is this true?

4. Is there a preferred distance between the wing and the HS? Should I set that and move CG only with clay?

5. I'm making a new flight log below my old flight log with added parameters and neatness. Am I missing anything?

6. I'm already looking into rubber/propeller optimization because I think that we'll hit 2 minutes and above soon. What advantages does a broad flare propeller offer compared to a symmetrical Ikara? Why do people sand that and not the symmetrical one?

7. For dud flights (flights that immediately dive or stall) I tend not to record them in the flight log, because I usually make adjustments and finger-wind the propeller a bit before launching again. Is this okay? There are 31 flights recorded, but probably 20 more in duds and another 20 unrecorded from the tournament.

8. Any comments on my flights?

Thanks to all of you for providing wonderful information in a public forum so that areas without any special coaching (like mine) have the ability to do well in flight. I hope that my flight log, post, and video can help others wishing to get better at flight like I am. And sorry for the wall of text!

Flight 1 (1:23): https://drive.google.com/file/d/1LA0HER ... share_link
Flight 2: (1:12): https://drive.google.com/file/d/18EtYh8 ... share_link
Plane Image: https://imgur.com/a/Jtvu6Va
Flight Log: https://docs.google.com/spreadsheets/d/ ... sp=sharing

[danxmemes]

Hi, I have a few questions about my plane that I recently built and flew, (div B)

When I am flying my plane, I notice that it does not climb very well, and goes into a constant stall where the nose is pointed very upwards when it is flying. How can I fix this? Right now times are around 40 seconds and I would assume that a better gliding flight will yield better times.

Second, when winding rubber, I find that I am only able to get to 1100-1200, instead of the 1400 I was able to achieve before. I follow the exact same steps, as suggested in this forum, and rubber weight is still the same. How can I get the extra 200 turns?

Any help would be greatly appreciated, thanks in advance!