Flight B/C

[jander14indoor]

Also, DON'T LIMIT TEST FLYING TO GYM TIME!!! The MOST critical thing about this event is flying your plane and collecting data to make decisions with!! Fly ANYWHERE you can get time. While tall, unobstructed ceilings with large, clear floor space is nice, it isn't as important as just FLYING LOTS!! Fly in your school cafeteria, lobby, band room, multipurpose room. Wherever you can get say 30 feet by 30 feet of floor space and 8 ft plus ceiling height. No, you won't get 2-3 minutes time there, but you CAN learn the basics. How to trim for steady flight, how to trim for steady turn, how to make it climb. 80-90% of what you need to know. Then use the hard to get gym time to refine that last 10-20%.

And, look up flying on 1/2 or 1/4 motors. Its been covered in these forums in the past. You can simulate flying in a tall site while flying in a low site to 95% of what you need to know with those.

Fly as often as you can!!!! Not as often as you can get into a gym.

Jeff Anderson
Livonia, MI

[randomdogonapc]

Our school has two Div B teams, one younger team made up of mostly 6th graders, and an older team of 7th and 8th grade students. The kit was split so that each of the two Div B Flight teams would have enough materials to build one plane.

EDIT: Thanks for the advice Coach Jeff

[drcubbin]

Our school has two Div B teams, one younger team made up of mostly 6th graders, and an older team of 7th and 8th grade students. The kit was split so that each of the two Div B Flight teams would have enough materials to build one plane.

Oh, that makes more sense. My bad-misunderstood what you said.
jander14indoor, what would you recommend if the school doesn't have a cafeteria, lobby room, band room(etc.)? There is nowhere that has higher than 8ft. It's about to be winter break, too... I'd use the gym, but the AC is so strong in there.
I do have a warehouse reserved but I only get around 3 hours a week in there. Would that be enough flight time? I'm hesitant about flying outdoors, because I've heard stories of planes lost OOS, or stuck in trees, or mylar torn from grass...

[jander14indoor]

More critical than height is floor space. You need probably a minimum of 20 by 20 feet, better 30 by 30. Smaller spaces require smaller circle, which tends to drive drag. You want to fly in as wide a circle as practical in any given site. An 8 ft ceiling will let you get good, if limited data.
As to how to maximize the high ceiling height time you have, you need to plan your flight time well. Know what aspect of flying you will test before you go fly. Take lots of data and use it to guide your next session. This is in general a critical skill for science/engineering work.
In low sites, work on steady state, level flight trim. You want to learn what trim condition and what torque levels give longest, steadiest flight.
To work on climb, as mentioned previously look into partial motor testing. You can test the launch and climb portions of the flight in even an 8 foot ceiling.

And I'm hoping some of the other experienced mentors will step in!

Jeff Anderson
Livonia, MI

[drcubbin]

Yeah I don't have anywhere that is 20*20 except the warehouse.. is there any way to adjust circle size reliably? I managed to get my circle wider after moving CG, but that's pretty much all I've done so far. I can't adjust the stab tilt or the rudder offset--is there another way? I'm considering modding my second FF plane but I'm also too scared to mess with my last plane...
Thank you!

[bjt4888]

Yeah I don't have anywhere that is 20*20 except the warehouse.. is there any way to adjust circle size reliably? I managed to get my circle wider after moving CG, but that's pretty much all I've done so far. I can't adjust the stab tilt or the rudder offset--is there another way? I'm considering modding my second FF plane but I'm also too scared to mess with my last plane...
Thank you!

Cat,

Rudder offset or stabilizer tilt or left wing washin will all affect the circle size (thrustline too, but you're not going to change this most likely). Often, any change in one of these settings will require changes in other settings. Rudder settings have more effect during the early part of the climb; the high power portion. Stabilizer tilt has more effect during the later portion of the flight. More rudder setting will usually cause a slight rolling/diving tendency. So decreased rudder might mean that left wing washin needs to be reduced too. And decreased rudder might lead to a slight stall (which, as you have found with your glide tests, is very hard to see in this year's wide wing short tail moment airplanes). This slight stall might need a small decrease in wing incidence or (not too often) a slight movement of CG forward (very slight; like 1 mm maybe).

And, on to a different trim story, more propeller pitch, which will likely require thicker rubber and higher launch torque, will often cause tighter circle size due to rolling. So, thinner rubber and lower propeller pitch can reduce roll and increase circle size.

All this being said, the circle size I saw in your last video looks just fine.

Brian T

[drcubbin]

Thank you so much! Yeah, I'm mostly concerned about my circle size possibly being too big for certain sites I might fly in this year. I was thinking of just going crazy with logging and noting every single adjustment made, but I'm curious as to if there's a better way to do this.
I think I'll just focus on improving the plane before worrying about things like this. Thank you for your advice!

[jander14indoor]

Two approaches to gathering data effectively.
One, most commonly taught, but not very efficient, particularly with non-linear things like aircraft, is to change one factor at a time. Problem is, it won't show you interactions.
Two, more efficient, shows interactions, good for non-linear systems, but harder to understand and implement crazy is something called Design of Experiments (DOE). The math behind WHY is pretty high level. BUT, the how is actually pretty easy to implement (follow some simple rules and basic math with given equations), with only one hard thing. Picking the right factors to vary. But you've gotten a lot of hints on those already. The trim factors already discussed! Unfortunately DOE is a little deeper than space allows here, but do some looking on the web for how to make it work.

Jeff Anderson
Livonia, MI

[Sorrow2]

I'm new to flight can someone give me a good kit for flight???

[randomdogonapc]

I’ve noticed that throughout this forum topic, there have been reference to a document with formulas relating to the motor turns and torque, as well as a video on winding. I can’t seem to find them, can someone help me? Also, is the optimal length of the motor one of those things that you have to test in increments, or is it something that is calculated? Thanks in advance for the responses.