****f3b Speed****

[neilcharrison]

Hi everyone

I am getting back to F3B after a fews years break and things have moved on considerably, I am hoping you experts can help me out as our season starts soon and I need to get in some serious practice.

The BIG question....what is the best technique for task C, SPEED?

(other than lanuching high and keeping my time around 13 seconds!)

[dlgdude]

Launch high, fly smooth, don't cut....

[djklein21]

Tips for Practicing F3B,

Break down your skill set into smaller segments that you can practice.

Launch
Plane setup
Piloting technique
bucket/zoom technique
pushover timing and technique

Float back-
After peaking altitude from your launch, you need to get your plane into an entry point consistently every time. No matter the wind direction, or zoom direction, you need to drop into the course from the same point every time. Speed should look like it was flown by an autopilot, the same way, every time (with very small variations due to conditions). So as soon as you push over after the zoom, get your plane flying back to the drop in point. Slightly camber the plane, and fly it back at a slow distance speed. Too slow hurts efficiency since you are carrying weight, but too fast will not give the pilot time to be ready for the course. Once your plane is stable and heading the right direction, orient your feet and shoulders parallel to the course. This will give you a reference for flying parallel and straight to the course. Before dropping in, make sure to glance over to base B, so you know you are oriented correctly.

Now for the course-
Transition your plane to a reflexed/seed mode and dive to gain speed before entering the course. You should dive off more than half your altitude before entering the course. Once you enter the course, you should be flying relatively flat legs, only diving enough to keep your speed up. Older planes have less top speed, so they will enter higher, and fly steeper, newer lanes have thinner faster wings which will fly faster, flatter legs. Anticipate your turns, rolling up at least 95 degrees, and pulling consistent and smooth on your elevator. You should not bang the turn. Turning to sharply kills your energy.

As you practice more and more, you will become more consistent, and get a feel for how much ballast, and how much initial dive you can do. It takes a lot of practice. Practice flying a "race track" course, where you only turn one direction every time. Your first turn should be away from the base, then your A turn will be towards you, then again away, and then finish.

Practice, practice, practice. Get friends, and practice.

[bOjO]

David,

According to you why is it better to turn toward you at the base A... I was discussing this question with KP and the argument was that you have a way better view of your trajectory when the plane comes toward you... I completely agree with that but still find that excessively dangerous.

All the top pilots are flying the speed run this way ?

Joel

[djklein21]

The idea is to run a repeatable course every time. If you always turn away, you get further and further away. Also, running a race track course usually forces you to run more parallel to the course. If you turn in every time, you tend to always run diagonal to the course.

Also, turning in at B and away at A, you are more likely to cut the safety line. You can do whatever you like, but the idea is to do it the same way every time.

[FLY F3B]

David,

According to you why is it better to turn toward you at the base A... I was discussing this question with KP and the argument was that you have a way better view of your trajectory when the plane comes toward you... I completely agree with that but still find that excessively dangerous.

All the top pilots are flying the speed run this way ?

Joel

Hey Joel, I agree with David, and Kyle that turning toward you at base A is best for judging the trajectory, and for consistency. Don't let the slope fears influence which direction you turn. My dad always taught me to turn away from the slope, thus preserving his airplane so he would still have something to fly after I was finished. Turning toward is only dangerous if you only turn 90 degrees. But not to worry, you are going to keep pulling on that elevator, and complete the 180 degree turn.

For speed courses flown on the left side of the safety line, fly a left hand pattern. All left turns. Away from the safety line at base B, and toward you at Base A. Opposite direction for courses on the right side of the safety line. All right turns, again away at B and toward at A. There are times when wind will dictate something other than this straight racetrack style, but that is not what needs to be worked on at this stage. The racetrack style will keep you from wondering which way you are going to turn, and let you prepare well in advance, and even visualize the flight more accurately. Try it, and like Fred says, don't let fear be a factor.

Cheers,

Mike

[fearfactorfred]

Try it, and like Fred says, don't let fear be a factor.

Cheers,

Mike

Joel, I know how you feel dude. I'm still fighting those fears too. I guess that's why I like f3b so much, there's never a dull moment. :eek:

Good thread topic. Good info. ;)

Hopefully be practicing these techniques this weekend with my new plane :eek:

B good,
Fred

[F3B Fly Faster]

It all depands on what you feel comfortable with, left or right hand circuts. For me I fly left hand better then I do right hand, it comes from many years of flying pylons.

[bOjO]

Ok... thanks for the explanations. Dave's argument is a very good one: flying a race track avoid flying on diagonal...

I hope I will find a winch soon, I really want to practice this point progressively.

Joel

[luvF3b]

I tend to agree with most of what is being said regarding the flying style. Someone commented on the difference between the models. The modern F3b gliders (eg Radical, Ceres) are flying longer dive times and flatter courses because they have less drag compared to the older style models that dive less, but fly a steeper course. I'd like to add that some models have more "grip" in the turn, meaning (at least to me) that such models can turn tighter for a given drag, ie speed loss. So turn performance is very important, because it is the most energy sapping part of the speed run.

But to look at model setup. Speed performance is heavily dependent on model setup for not only the launch, but also everything after that - dive performance, straight line speed and handling, roll performance and pitch performance in the turn.

Dive performance.
The model is flying at near zero lift in a vertical dive, and the Reynolds number is increasing over time as the model accelerates. At zero lift and slow speed, the natural foil probably produces the least drag, once the Reynolds number rises above around 400K (about 100 km/hr) increasing amounts of reflex flap are needed to keep low drag at near zero lift. Perhaps the model might benefit from only clicking into speed mode as the dive is established or later? The amount of reflex flap to use is therefore dependent on the flight speed of the model. It is also dependent on the amount of camber in the natural foil. So for high flight speed, reflex might be good, and for high camber profiles (eg 2%) reflex would also be good. The more speed and more camber, more reflex...to a point. Xfoil or its many interfaces can be used to get some idea of the best reflex flap setting.

Straight line speed and Handling
Flying a slight dive line on the straights in the course also gives near zero (coefficient of) lift from the wing, so the comments about reflex flap also apply from above. Also note the comments about the best flap setting to use as speed varies. Perhaps a smaller amount of reflex is needed in the later laps?

On the laps, typically small course corrections are required to maintain the correct dive line etc. A pilot wants to make these corrections with precision, so for me I use a substantial amount of exponential on elevator. Because these small corrections only change the (coefficient of) lift by a small amount, and the drag (depending on the profile) doesnt change much so the camber control on the wing is not actuated by small elevator stick movements. I find that the CG is completely un-important for straight line speed performance.

Roll Performance
The model has to roll axially around the fuselage, perhaps with the slightest yaw into the turn, if any. When I say axially, I mean around the fuselage's center line. I use full span ailerons (ie aileron to flap mix) to maximize the roll rate for a given deflection. Differential on the outboard ailerons is set to provide rolling without yaw, or if any, yaw slightly toward the turn direction. Differential on ailerons is about 55% up 45% down. Differential on the flaps is set more to produce the axial roll. Eg if the model is rolling around the bottom wing tip when returning from a 90° bank, less flap differential is dialled up (more down going flap due to aileron mix). This tends to bring the roll axis inward from the bottom tip towards the fuselage. (differential on flaps is around 50:50, or sometimes 40:60)

An added complication is that the amount of differential needed changes as the model speed and attitude change. You may be forced to compromise (ie too much differential at 250 km/hr, and too little at 100 km/hr)

Pitch Performance in the turn.
I commented earlier that the CG is of little importance in flying the straights, but in the turns, the CG is vital. The CG drives the sensitivity of elevator. A rearward CG will require smaller elevator throws for the same turn response. (ie wing Cl) Get this wrong with too much elevator and too rearward CG, and the model will be too unstable. Back off a bit with more forward CG, or lower elevator movement and the wing now works in a lower drag range because you have constrained the Cl the wing can be pulled to.

Step 2, match the exact amount of camber the profile needs to minimize the drag for the wing Cl being commanded by the elevator pull. I do this by looking at turn diameter vs Cl plots to get the Cl, then look at the lowest drag flap setting for the particular Cl needed. In concept I set the model up to do 40, 30, 25, 20, 18, and 15 m diameter turns using a multi point elevator to camber mix to optimize the amount of flap deflection needed for each diameter. This is a starting point, and then modifications to the curve are accomplished through lots of flight testing. The curve for best response is typically very non linear.

Another tip...ever pulled up to have your model exit the turn wiggling in yaw? Add a heap of exponential to your rudder so that a less than pure elevator pull on the stick does not influence the rudder much...wiggly turns fixed.

I'm hinting that the model setup is vitally important. To do this properly, when elevator is pulled, both elevators need to be moved by the same amount (otherwise you get yaw from an elevator pull!) When elevator to camber flap mix is used, the ailerons and flaps need to move by the same amount across the wing, left and right, inboard and outboard (otherwise you get roll from an elevator pull). Rudder needs to be set with differential (otherwise you get a pitch response when you command rudder).The idea is to make the model as easy to fly as possible, and not have the pilot fighting to overcome cross coupling between roll, yaw and pitch when a stick is moved.

Finally, I'd say that for me the launch is close to the hardest part in speed. Everything flows from the launch. A poor height means either a lower dive time, or for the same dive time you have been practicing and then flying the same course to hit the ground on the second lap. A compromise is clearly needed. Necessarily, the dive time and course flown will depend on the launch height. You want to carry as much ballast as the model can be reasonably be launched to, and to do that in less than ideal conditions takes immense skill. The skills involve things as varied as throwing the aeroplane, to weaving it on the line to build maximum tension (circle towing anyone???), releasing at the right climb point and right direction through to an optimal zoom. I wont talk about the winch setup!

Suffice to say, without a good launch, everything else suffers. Work on launch first!

Flying technique...I couldn't resist! With highly ballasted models, once speed is attained, you only scrub speed off by increasing drag. The model setup stuff I talked about above ensures that the base level of drag is minimized through....wait for it....setup! The rest is up to the pilot, he (or she) must minimise the additional drag by applying the correct control inputs and flying the correct course. Dive lines on the straights need to be managed so that higher drag models are dived at a higher angle to overcome the drag. Rolling into the turn scrubs off speed, so the "racetrack course" actually has some merit because it involves less rolling. Turn diameter is a payoff between drag production (ie loss of speed) and the turn time ( time spent not heading in the right direction) There is an optimum turn diameter for every type of air and model with a good pilot sensing the "grippiness" of the air and pulling a tighter turn without the usually necessary speed loss penalty.

I mentioned launch earlier, without a consistent entry height, consistent practice on the course can not be made. Pilots will need to improvise their dive times, and once on the course improvise their dive angles and turn diameters to extract just that little more from the air they are in for the launch height they started the entry dive at. Because launch heights are inherently variable, clearly the top pilots work to minimize their height loss on launch and in doing that they minimize the range of improvisations needed.

Thank you for the opportunity to preach as I understand it. I'd be happy to have any of my thoughts modified by a little constructive criticism!

John

[*Harry*]

Great information, what about your thoughts on distance?

[thechalster]

Excellent thread. Thanks to all.

[Ricardo RW]

Great information, what about your thoughts on distance?
Yeah, I'd like to know if this recommendations apply to the distance task too.

Thank you for the writing by the way.

[luvF3b]

Distance is a much more teamwork/tactical task than speed: it depends soooo much on air reading skills and also height management. It is very tempting to accelerate and burn height in good air only to find that the last 1:30 minute on the course is spent under the lift at close to minimum sink trying to stay in the air for the 4 minute task. The model obviously has to be placed in the correct air, and this is where the tactics and teamwork play a vital role. Flying diagonal laps might take you to the better air, but you travel a longer distance, perhaps simply turning toward the air at both base A and B will take you there, perhaps something more aggressive is required. Better height conservation or a faster lap pace might be needed. A good caller will tell you that. After all you are just the pilot, not the caller, not the tactician, not the turn judge!

Before the distance run, you talk tactics with your team. Is the air thermic? Can the thermals be circled off course to gain height? Where is the best place in the sky to fly? How much ballast? Based on previous distance rounds how many laps gets the 1000?. Based on all this information (and perhaps more) target lap paces are set for perhaps the first 1:30. The important thing is that the team is aware of your plans. The air you find yourself in will make the whole diffference to the next 2:30. Here the team play a vital role too.

There are three members of the team: 1) the caller tells the pilot which direction to turn based on the tactical input, and estimates the turn for the pilot (breaking that down into simple language "turn out in 30...20...10...turn!"), tells him how many laps have been done and in what time ( breaking that down into simple language "you're on 6 lap per minute pace") 2) The tactician feeds information to the caller, observing other models, pointing out the best air, and advising the pilot of the number of laps needed to get the 1000 points (again in simple language... "fly faster, you need 8 laps in the last minute". 3) The turn judge simply looks at the turn signal lights, and listens for the turn sound. Distance is very hectic, and a turn signal can easily be missed unless a team member is dedicated to that task only.

Add to that the fact that the task is flown man on man against up to 5 other models with you racing in the same working time as other pilots, avoiding midairs, and using other models to judge the turn position and air makes this task the most hectic, team based, and enjoyable tasks of all for me. A high lap count distance run is a prolonged release of adrenaline, not the same as speed where you have only a short time to enjoy it!

Launch
Basically the same as speed. I am a fan of carrying quite a lot of ballast for distance (at least 60% of speed weight if not higher).

Pace control on the straights
Distance is flown at a wide range of speeds. Slowest pace might be 4 laps per minute (ca 35km/hr, Cl=0.7..a guess!), and fastest might be 12 laps per minute( 150 km/hr, Cl=0.05 another guess!). The model setup required changes radically between these two extremes.

At 4 lap pace, depending on the model, to conserve height a little positive camber might be needed. Dont worry about the camber slowing things down, the ballasted weight will easily provide the 4 lap pace, and the ballast provides the smug knowledge that the model can be accelerated at any time the pilot decides to "let go of the horses". The camber ensures that minimum height loss happens hopefully enabling the pilot to gain a height advantage over the other competitors.

At 12 lap pace, the model would be close to full speed mode (ie reflex camber)

In between these two extremes is a whole range of camber settings that are appropriate. I set my model up to have variable camber between the two extremes above. With a change in the camber setting, the elevator also changes setting. The elevator drives the speed of the model, the camber selects the lowest drag for that speed. To have this range of trims, the CG is set a little more forward than in the speed task.

Roll control
At 4 lap per minute pace, the model is flying at much higher Cl, so more differential is needed, and perhaps a little aileron to rudder coupling too. This trim is much closer to the classic minimum sink trim. At 12 lap per minute pace, we are in speed mode, where differential is closer to 50:50, and no aileron to rudder coupling.

I change the differential, and aileron to rudder coupling based on the lap pace.

Pulling the turn
The same comments apply here as with the speed turn. The optimum amount of elevator to camber coupling depends on the speed though. I find that more seems to be needed at slower speeds.

The radio can be set up to change the amount of elevator to camber mix depending on the amount flap position by enabling mixers based on lap pace. I use a Graupner JR MC 24, but there are a select few transmitters on the market that provide the same functionality.

Again the setup is designed to minimise the drag of the model at all of the reasonable speeds encountered. Also the setup is designed to ABOVE ALL make the model easy to fly. For lap pace I have a rotary knob set up on my transmitter that selects the appropriate camber and elevator setting and differential and aileron to rudder couple for 4 lap per minute pace. Wind it the other way, and it is set up for 12 lap per minute pace. In between, all the intermediate settings.

So, when my caller tells me to fly faster, i simply wind the knob a little, knowing that the model will accelerate, and find its next low drag trim at a slightly higher speed. The knob selects the lap pace for the model and the roll and pitching performance.

Good luck in distance, it is far more pilot/team skill than any other task I have flown, and the information overload at times can be amazing, especially when you are punching out 5 second laps!

Cheers,

John

[Ricardo RW]

Wow! Only I can say, besides thank you, of course.

Now I need to digest all this info and practice a lot.

Thank you for your input.

[thechalster]

Distance is a much more teamwork/tactical task than speed: it depends soooo much on air reading skills and also height management. It is very tempting to accelerate and burn height in good air only to find that the last 1:30 minute on the course is spent under the lift at close to minimum sink trying to stay in the air for the 4 minute task. The model obviously has to be placed in the correct air, and this is where the tactics and teamwork play a vital role. Flying diagonal laps might take you to the better air, but you travel a longer distance, perhaps simply turning toward the air at both base A and B will take you there, perhaps something more aggressive is required. Better height conservation or a faster lap pace might be needed. A good caller will tell you that. After all you are just the pilot, not the caller, not the tactician, not the turn judge!

Before the distance run, you talk tactics with your team. Is the air thermic? Can the thermals be circled off course to gain height? Where is the best place in the sky to fly? How much ballast? Based on previous distance rounds how many laps gets the 1000?. Based on all this information (and perhaps more) target lap paces are set for perhaps the first 1:30. The important thing is that the team is aware of your plans. The air you find yourself in will make the whole diffference to the next 2:30. Here the team play a vital role too.

There are three members of the team: 1) the caller tells the pilot which direction to turn based on the tactical input, and estimates the turn for the pilot (breaking that down into simple language "turn out in 30...20...10...turn!"), tells him how many laps have been done and in what time ( breaking that down into simple language "you're on 6 lap per minute pace") 2) The tactician feeds information to the caller, observing other models, pointing out the best air, and advising the pilot of the number of laps needed to get the 1000 points (again in simple language... "fly faster, you need 8 laps in the last minute". 3) The turn judge simply looks at the turn signal lights, and listens for the turn sound. Distance is very hectic, and a turn signal can easily be missed unless a team member is dedicated to that task only.

Add to that the fact that the task is flown man on man against up to 5 other models with you racing in the same working time as other pilots, avoiding midairs, and using other models to judge the turn position and air makes this task the most hectic, team based, and enjoyable tasks of all for me. A high lap count distance run is a prolonged release of adrenaline, not the same as speed where you have only a short time to enjoy it!

Launch
Basically the same as speed. I am a fan of carrying quite a lot of ballast for distance (at least 60% of speed weight if not higher).

Pace control on the straights
Distance is flown at a wide range of speeds. Slowest pace might be 4 laps per minute (ca 35km/hr, Cl=0.7..a guess!), and fastest might be 12 laps per minute( 150 km/hr, Cl=0.05 another guess!). The model setup required changes radically between these two extremes.

At 4 lap pace, depending on the model, to conserve height a little positive camber might be needed. Dont worry about the camber slowing things down, the ballasted weight will easily provide the 4 lap pace, and the ballast provides the smug knowledge that the model can be accelerated at any time the pilot decides to "let go of the horses". The camber ensures that minimum height loss happens hopefully enabling the pilot to gain a height advantage over the other competitors.

At 12 lap pace, the model would be close to full speed mode (ie reflex camber)

In between these two extremes is a whole range of camber settings that are appropriate. I set my model up to have variable camber between the two extremes above. With a change in the camber setting, the elevator also changes setting. The elevator drives the speed of the model, the camber selects the lowest drag for that speed. To have this range of trims, the CG is set a little more forward than in the speed task.

Roll control
At 4 lap per minute pace, the model is flying at much higher Cl, so more differential is needed, and perhaps a little aileron to rudder coupling too. This trim is much closer to the classic minimum sink trim. At 12 lap per minute pace, we are in speed mode, where differential is closer to 50:50, and no aileron to rudder coupling.

I change the differential, and aileron to rudder coupling based on the lap pace.

Pulling the turn
The same comments apply here as with the speed turn. The optimum amount of elevator to camber coupling depends on the speed though. I find that more seems to be needed at slower speeds.

The radio can be set up to change the amount of elevator to camber mix depending on the amount flap position by enabling mixers based on lap pace. I use a Graupner JR MC 24, but there are a select few transmitters on the market that provide the same functionality.

Again the setup is designed to minimise the drag of the model at all of the reasonable speeds encountered. Also the setup is designed to ABOVE ALL make the model easy to fly. For lap pace I have a rotary knob set up on my transmitter that selects the appropriate camber and elevator setting and differential and aileron to rudder couple for 4 lap per minute pace. Wind it the other way, and it is set up for 12 lap per minute pace. In between, all the intermediate settings.

So, when my caller tells me to fly faster, i simply wind the knob a little, knowing that the model will accelerate, and find its next low drag trim at a slightly higher speed. The knob selects the lap pace for the model and the roll and pitching performance.

Good luck in distance, it is far more pilot/team skill than any other task I have flown, and the information overload at times can be amazing, especially when you are punching out 5 second laps!

Cheers,

John


Could you run though in more detail how you programe this on a MC24. Which mixers/functions you user and how. I currently have three differnet flap setting for distance but the Camber to elevator remains the same.

[davidleitch]

Why roll more than 90 degrees? Is that so you can keep the descent up in the turn and whip the tail out of the turn at full speed?

[luvF3b]

The MC24 is a top end radio which has a high level of programmability.

The flight modes (launch 1, launch 2, speed, distance, thermal 1 and thermal 2 for me) are user defined with flap, elevator, aileron presets, a different wing mixer main menu and differential setting for each flight mode. 12 free mixers are also available, which can be enabled/disabled based on flight mode, or hard switch or soft switch.

In distance I use a proportional channel (eg slider or throttle or rotary) the channel can be mixed to elevator, flaps and ailerons, and so this becomes a camber adjust channel which re trims the elevator neutral for the desired speed, and the appropriate camber for that speed. Soft switches can be assigned to the same proportional channel based on that channels position, which can be used to switch mixers such as aileron to rudder, or elevator to camber etc.

So the assignment of the proportional channel is used as a speed adjust function. In one direction, to fast speed (say 8 laps per minute) the camber might go to reflex, with low aileron differential setting, aileron to rudder mix turned off and a different elevator to camber mix setup. In the other direction the proportional channel changes the functions(4 lap per minute pace) now with some positive camber, elevator re trimmed, and various mixers (eg aileron to rudder, or elevator to camber) turned back on . It makes flying according to the pace required a little easier, simply position the proportional channel to desired trimmed airspeed, and the handling qualities are also adjusted automatically for that speed. No flicking of switches, I stay in the distance flight phase for the whole period of time on the course, and use the proportional speed adjust only. (oh and the odd input of aileron, elevator and rudder...these radios are good, but not that good :rolleyes: )

If you go into this setup a little more, you will see the reason for me saying in an earlier post a more forward CG in distance (than neutral). The forward CG is exactly what is needed to allow re trimming of the elevator to control the trimmed speed.