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Old Dec 15, 2011, 12:28 PM
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Are there any altitude limits during cross-county competitions?
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Old Dec 15, 2011, 12:42 PM
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Only what you can see with your eyes. Most racing takes place between 500-1100m with the occasional low save. My highest logged flight was 1780m. It depends a lot on the air quality and the chord of the plane.
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Old Mar 15, 2012, 01:25 PM
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Old Mar 15, 2012, 01:37 PM
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Quote:
Originally Posted by ShredAir View Post
Nope, not anymore. It's how FAST you can fly it on a particular course. RC XC soaring has evolved to be as close to full-sized soaring as possible: best average speed on course wins. http://xcsoaring.com/organize.html is an overview of what's involved in a typical XC contest. It's dated a bit, but it provides basic info.

Dieter Mahlein, ShredAir
Hello Dieter, there is no "speed" or time requirement in FS XC soaring. I think what you are referring to is called sailplane "racing" where a winner is picked based on the best speed over a designated course. This "task" also has a time limit of x amount of hours.
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Old Mar 31, 2014, 08:23 AM
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I am going to bump this thread back to the top as visitors to this forum who are not XC pilots, like me, might find it interesting. And I am going to ask a few questions too.

I get the size and cord design for visibility.

Are we still working with the same kind of airfoils found on typical TD ships? MH32, Drela 40 series, ???? Or do XC planes typically use different airfoils?


I get the weight needed to attain glide speed over the course as compared to our mad passion for light TD planes. Do you typically fly at 5Kg?


Do these big gliders eat a lot of battery? What would you use in a 10K goal and return?


For an XC contest, How long are you typically on course? I know that depends on how far you are going but what is a typical flight, if there is such a thing?


How is the course typically marked for a contest?

* Spots on a map?
* Way points on a GPS?
* Markers on the road?
* Do you sign in at check points?


In an XC competition, like the NATs, what do you do if you land out?
You launch, you climb you go on the course. Somewhere along the course you can't find lift and you land out. What do you do, assuming you land safely and can reach the glider?

* Do you go back to the start and launch again?
* Do you look for a place to set up a hi-start or a winch and relaunch?


Do you need to file a flight plane with the local airports? I presume you are going to be large enough and high enough to show up on radar.


I don't know that I will ever attempt a 2K or a 10K much less a competition like the NATS, but the concept still fascinates me.
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Old Mar 31, 2014, 09:07 AM
I'm all about that bass
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United States, IN, Indianapolis
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Quote:
Originally Posted by aeajr View Post
How is the course typically marked for a contest?

* Spots on a map?
* Way points on a GPS?
* Markers on the road?
* Do you sign in at check points?


In an XC competition, like the NATs, what do you do if you land out?
You launch, you climb you go on the course. Somewhere along the course you can't find lift and you land out. What do you do, assuming you land safely and can reach the glider?
I have been to the XC Nats twice never as a contestant once as a driver and once doing the non contest entry LSF task entry. The XC Nats course has always been a simple ~10K goal and return course (with options to do a 1K and 2K in recent years). The turn point has been some kind of landmark. A church, an intersection, etc.

At the Nats all launching is done from the launch area. In years past it was the AMA national flying site and in recent years a school. If you land you you get your plane (asking for permission if landing on private property) and drive it back to the launch site. That might entail disassembling it or it might not.

If you are out for the Nats and have the time you should consider doing XC. You could do even just a day of XC on Sunday then go into RES/Nostalgia Monday and Tuesday and then to Unlimited and finaly to ALES (or F3J).

If you got all your LSF level stuff in order you could get to where the last task is the 2K and then on the same day do the 2K and then if you get signatures you are allowed to immediately start on the next level's tasks (null and void if there are problems with your level you are finishing) and then you could try the 10K after that.

Ryan
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Old Mar 31, 2014, 11:50 AM
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If you check out this thread I go through a series of airfoil investigations. I ended up with a custom designed airfoil from Philip Kolb but the short answer is that the Supra foils are pretty hard to beat in the analysis I did.

http://www.rcgroups.com/forums/showthread.php?t=1256550

I rarely fly at less than 5 kg. Only if I think it will be a super light day.

It all depends on how fast you do the 10K. With a good crew and some experience it will not take much more than 30 minutes. You can do that with 4 AA. I have flown 5+ hours on 3600 mah with 6 servos. I now use either 4000 or 5000 and once I figured out how to charge them it is never an issue. Remember that you are trying really hard to stay off the sticks.

The west coast courses used to be either open distance or very long, 60+ miles. They have trended shorter with a fixed distance of 15-30 miles. These usually take 30 minutes to 2 1/2 hours depending on the conditions.

The course it usually marked with pie plates. After a while you get to know it like your neighborhood. The GPS in the plane marks when you go through it.

If you land out you go back and start over. There used to be contests where people relaunched from the road but that was a long time ago. The planes and skill level have gotten to the point where a lot of people are capable of finishing.

We generally fly away from airports, except at Montague where you have to look out for full scale.
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Old Mar 31, 2014, 12:21 PM
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See my replies in red below. They are based on my experiences with west coast XC contests. I have not been to the Nats XC and from what I understand the tasks are quite a bit different.

Quote:
Originally Posted by aeajr View Post
I am going to bump this thread back to the top as visitors to this forum who are not XC pilots, like me, might find it interesting. And I am going to ask a few questions too.

I get the size and cord design for visibility.

Are we still working with the same kind of airfoils found on typical TD ships? MH32, Drela 40 series, ???? Or do XC planes typically use different airfoils? I think in general the airfoils used are similar to the airfoils used in modern TD ships. If anything they may be modified slightly for better performance at higher speeds. Others who have actually designed their own XC gliders may have more to say about airfoils. I am currently using a modified Xplorer II for an XC ship.


I get the weight needed to attain glide speed over the course as compared to our mad passion for light TD planes. Do you typically fly at 5Kg? Most of the gliders fly at or close to the maximum 5kg limit


Do these big gliders eat a lot of battery? What would you use in a 10K goal and return? I usually run batteries that have a capacity of 4 to 5 amps. Most of the time this is way more than is needed.


For an XC contest, How long are you typically on course? I know that depends on how far you are going but what is a typical flight, if there is such a thing? Most of our tasks are now in the 15 to 40 mile range. The duration's can be any where from less than an hour to 3 or 4 hours. In past years we have had tasks in which the goal was the longest single flight. These flight could last 6 or 7 hours and cover 100 miles or more.


How is the course typically marked for a contest?

* Spots on a map?
* Way points on a GPS?
* Markers on the road?
* Do you sign in at check points?

The course or task is specified as a sequence of turnpoints with a start and a finish. The turnpoint locations are shown on a map and the gps coordinates are given. The turnpoints usually also have a marker on the road.

For the purposes of scoring, all gliders are required to have an onboard gps logger. After the flight the logger is turned into the person in charge of scoring and the flight is scored by computer using a fullsize soaring software



In an XC competition, like the NATs, what do you do if you land out?
You launch, you climb you go on the course. Somewhere along the course you can't find lift and you land out. What do you do, assuming you land safely and can reach the glider?

* Do you go back to the start and launch again?
* Do you look for a place to set up a hi-start or a winch and relaunch?

I can't speak to the Nats, but at the west coast contests if you land out you pack up the glider and drive back to the Start line and if you have time you re-start and try again.


Do you need to file a flight plane with the local airports? I presume you are going to be large enough and high enough to show up on radar.

That depends on the location of the contest. Most of our contests are no where near any active airports. Montague is the one exception and there we have modified our course to stay away from the takeoff and landing approach. We have also coordinated with the airport manager so they are aware of what we are doing.


I don't know that I will ever attempt a 2K or a 10K much less a competition like the NATS, but the concept still fascinates me.
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Old Mar 31, 2014, 12:33 PM
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Quote:
Originally Posted by aeajr View Post
I am going to bump this thread back to the top as visitors to this forum who are not XC pilots, like me, might find it interesting. And I am going to ask a few questions too.

I get the size and cord design for visibility.

Are we still working with the same kind of airfoils found on typical TD ships? MH32, Drela 40 series, ???? Or do XC planes typically use different airfoils?


I get the weight needed to attain glide speed over the course as compared to our mad passion for light TD planes. Do you typically fly at 5Kg?


Do these big gliders eat a lot of battery? What would you use in a 10K goal and return?


For an XC contest, How long are you typically on course? I know that depends on how far you are going but what is a typical flight, if there is such a thing?


How is the course typically marked for a contest?

* Spots on a map?
* Way points on a GPS?
* Markers on the road?
* Do you sign in at check points?


In an XC competition, like the NATs, what do you do if you land out?
You launch, you climb you go on the course. Somewhere along the course you can't find lift and you land out. What do you do, assuming you land safely and can reach the glider?

* Do you go back to the start and launch again?
* Do you look for a place to set up a hi-start or a winch and relaunch?


Do you need to file a flight plane with the local airports? I presume you are going to be large enough and high enough to show up on radar.


I don't know that I will ever attempt a 2K or a 10K much less a competition like the NATS, but the concept still fascinates me.
there is always room for improvement with regards to airfoils. Greg Norsworthy is using a custom XC airfoil designed by Philip Kolb. His design is also a smaller area wing for greater wingloading and speed. Not sure what the MXC airfoil is but it is older, I once heard it was a modified RG15 then later was told it was a modified 7037 (or MH32??). Still, the MXC is the most popular design, fast, stable and easy to fly. Super Supra flown by my team uses the same Drela 40 series as the TD Supra. Bagged carbon wing so not as accurate as the molded ships but a very capable XC glider, extremely strong. John Ellias is using a modified X2 (extended boom) with a stock wing but loaded to full 5kg. I think his wing is double carbon with a doubled joiner. It is very fast but remains to be seen how effective long term due to reduced visibility with the narrower 10 inch chord. I think probably the ideal XC ship would be a molded 4m X2 or Aspire but with a longer boom and a 12-13 inch chord for better high altitude visibility. Lots of different opinions on this however. I think just about everyone I've flown with can agree you need a high wingloading of at least 15 oz to be competitive in our west coast XC contests.

We all fly at 5 kg for max wingloading (speed). Greg and John fly gliders that have the capability to fly at reduced wieghts and lighter wing loadings but I havent seen them do it. The problem is that due to the long distances, varied terrian and long flight times, conditions will change and reducing wieght at the start in light conditions can easily turn into a problem an hour into the flight when conditions change, wind comes up, etc. We no longer fly distance tasks unless a pilot is attempting a 25K, 50K or 100K distance pin. Like full scale, we fly speed tasks now over a designated course with a specified start and finish line and turnpoints.

I dont think XC gliders have more power draw than the typical TD ship. But flights are much longer and wieght is no problem. Typical batteries are 3000 to 6000 mah. most are probably around 4000 mah. Used to be everyone flew with the big 6v lead acid motorcycle type battery. Now most use LifePo.

Courses are now all speed, typical course length is 15 to 40 miles. Flight times around 45 minutes to 2-3 hours. Average speeds are 15 to 30+mph. Less thana 15 mph average is considered slow, greater than 25mph average is considered fast, 30+mph is very fast. Consider that these average speeds include all the time sitting beside the road riding thermals back up to altitude.

Courses are marked with numbered pie plates stapled to the power poles along the road which indicate turnpoints. All the racers have GPS on board to verify hitting the turnpoints and time for speed scoring. Turnpoints are a 0.2 mile radius cylinder so the glider must cross into the cylinder to be considered valid. This method of scoring has been in effect for the last 4 or 5 years. It took a little getting used to but now all the regular teams are pretty good at it.

there is no "check in" at turnpoints. The GPS scoring verifies the legality of making a turnpoint.

If you land out you record the distance back to the previous turnpoint and go back to the start to relight if time permits. If conditions are very difficult and all teams land out then the contest essentially becomes a distance task and average speed no longer matters. This is pretty rare however as usually at least one team will complete the course.

Steve

ETA: just now read John's post... looks like we are all repeating each other.. ahahaha...
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Old Mar 31, 2014, 01:07 PM
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Repeats are good. They reinforce the validity of the information.


When you land out, do you get credit for that distance, assuming that would be useful in the format you are flying? Seems that a move to speed rather than distance is the norm now.
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Old Mar 31, 2014, 01:26 PM
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Some XC Videos I spotted

Launches - These are big gliders

Vyger 16' XC RC Sailplane Launching (1 min 9 sec)


156" Constellation Cross Country Ship (1 min 26 sec)





THESE VIDEOS TAKE IT ON THE ROAD


RC Cross Country Soaring (1 min 48 sec)



THIS ONE IS DONE WITH AN ELECTRIC FLYING WING, BUT GIVES YOU THE FEELING OF TRAVELING DOWN THE ROAD AFTER THE GLIDER.



Part 2: 10Kilometer Electric RC Cross-Country Challenge (5 min 50 sec)
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Old Mar 31, 2014, 01:29 PM
I'm all about that bass
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United States, IN, Indianapolis
Joined Feb 2004
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Quote:
Originally Posted by aeajr View Post
When you land out, do you get credit for that distance, assuming that would be useful in the format you are flying? Seems that a move to speed rather than distance is the norm now.
You asked about the Nats earlier, the Nats you get credit for partial distance. The Nats is a distance task (most laps or combination of laps and a partial lap) but obviously a faster glider means you can probably get more laps in.

Ryan
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Old Mar 31, 2014, 01:35 PM
I'm all about that bass
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I drove for this flight in Florida:

Gordon's 10K goal and return (1 min 6 sec)


Ryan
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Old Mar 31, 2014, 01:46 PM
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Quote:
Originally Posted by aeajr View Post
When you land out, do you get credit for that distance, assuming that would be useful in the format you are flying? Seems that a move to speed rather than distance is the norm now.
Yes, you get credit for that distance.

The full scale program that is used is called Winscore - http://www.gfbyars.com/winscore/
It uses file created by the onboard GPS loggers that are carried in all of the sailplanes for scoring and takes into account flights that do not complete the course.

Take a look at the Montague 2012 thread for photos of the scorings as well as some great videos to get some ideas on what happens at Montague.

Lift,

- Bob -
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Old Mar 31, 2014, 02:06 PM
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those big polyhedral gliders in the videos would be too slow for the way we fly XC now. Probably good for the Nats though.

the problem is the 5 kg limit. If we could raise that limit to say, 10kg we would be building bigger sailplanes and probably be loading them to 20-25 oz wingloadings. Bigger is better as long as you can get the right wingloading. Just look at the heavily loaded full scale open class ships with 50:1 or 60:1 glide ratios. Not sure our winches could take 10kg, thats 22 lbs.

We are stuck with the FAI 5kg limitation which means the direction is heading towards smaller higher loaded designs. John and Greg are trying to prove this. The rest of us will likely follow if it works. The advantage is maybe we really dont have to fly so high with these faster smaller airframes. The dissadvantage may be that we can get into more trouble at both very high and very low altitudes.

Steve
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