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Old Apr 26, 2010, 05:48 PM
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Getting Started in XC - Planes, tips, advice

First, I am very happy to see the new XC forum. I hope it is a big success.


Now, let's get a beginner thread going for those of us who want to take a taste of this part of the soaring hobby.

1) What are the key considerations when looking for an XC plane

2) R/E, RES, Aileorns, or Full house? Why?

3) What planes do you recommend? Where can you get them?

4) What would be a good skills development approach for someone, like me, who has no experience with this kind of flying? Can I develop skills based on my current planes, and AVA and a Supra, or do I need to have an XC plane to really work on my skills?

5) Can you really practice for XC if you don't have a place to run a real XC course? As far as I know there is no place near me where I can do a 2K G&R much less a 30K or even a 10K course.


Let's help the newbies get started. People like me!
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Old Apr 27, 2010, 12:24 AM
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This is a good question and part of what this XC forum should be all about.

Most of us that have been flying XC for awhile started out with whatever vehicle we had, usually a pickup and we were in the back sitting on beanbag chairs or milk crates or nothing at all, no wind protection other than the cab. A vehicle and a team of 2 or 3 is the first step. Next is the glider, if nothing else just use your TD ship.

I think the skills learned on a flat TD field that transfer well to XC would be basic thermalling, especially thermalling in wind. Being able to stick with a thermal in wind and chase it is essential to XC flying. Often we will catch a good thermal and end up turning the vehicle around and chase it back up the course, or if you're lucky chase it down the course. Being able to stay with a fast moving thermal can make all the difference. Sometimes slope soaring skills come into play in XC, also wave riding. Other TD skills, zoom launching and lawn dart landing have no bearing on XC.

Low level (handlaunch) saves is another valuable skill. Thermalling a 14ft span glider in a handlaunch thermal at less than 50meters is not easy but you can bet it will happen.

as for the XC plane the dominant gliders here on the west coast are the RnR SBXC and MXC, both aileron full house. I see no reason why a good RE plane cant compete and a few homebuilts have done well. There are some exciting new designs coming out as seen in some of the RCGroups threads (XCBD, #9 "Super Supra"). Primary consideration in an XC plane is wing loading for speed/wind penetration and chord width for visibility. Chord seems to be a more important factor than span when it comes to visibility. 12 inch root chord is minimum (SBXC is 12" and MXC is 14"). Around 160"-170" span, 12" to 14" chord and 15+ ounce wing loading is probably optimum. Max wieght is 5 kg (11 lbs). In XC hieght is everything and if you cant see it at 3000+ ft AGL you are in trouble. The bottom surfaces of the wing and stab must be a dark color, dark blue, dark red, etc. Flat black is the best. All dark colors will appear as black at high altitude. Personally, I've experienced problems with red not being as visible as dark blue or black but other pilots have not had that problem.

For serious XC flying you will need a vario. The Sky Melody, Piccolario and others are all good. Without the vario you might get lucky and make it 10 miles but luck will always run out, I dont know of any team here on the west coast that flies without a vario. Learning to fly the vario can be a challenge for some pilots new to XC. In XC it is the vario tone more than the visual signals that guide the pilot, especially from a moving vehicle. The vario will allow the pilot to find a thermal and re-center and core it at great, edge of visibility distances. After awhile it is not hard to learn to substitute the vario tone for the usual visual clues from the glider that we are all familiar with.

Assuming the pilot has the basic skills, XC is mostly about decision making. In TD decision making is paramount and in XC it is doubly so. Luck is always a factor but one of the great things about XC is luck is much less a factor than skill. In TD luck can carry you thru a 10 minute task. In XC a flight can last 2-6 hours and believe me, you cant get lucky that many times to fly that long. The best XC pilots arent really that much more skilled in flying as far as I can see. What seperates them is experience and especially decision making. Trust me, I'm still trying to figure out how they always win and I've been flying XC for over 10 years.
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Old Apr 27, 2010, 01:28 AM
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Trekbiker,

That was an OUTSTANDING post for a newbie like me. I hope others will add to the discussin.
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Old Apr 27, 2010, 11:20 AM
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Originally Posted by aeajr View Post
Trekbiker,

That was an OUTSTANDING post for a newbie like me. I hope others will add to the discussin.
AGREED!!! Thank you!

Scott

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Old Apr 27, 2010, 04:09 PM
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my 2c worth

#1 consideration for the plane is that it does not come apart. This can happen in an instant, especially high up and far away. Use as much of the 5k budget as you need and don't cut corners on things like hinges, linkages, wing rods, etc.

I like R/E for reason above, less things to blow apart and plenty of mass budget for the structure. That said I am helping design a larger Supra and am considering building one myself. Flaps or spoilers depend on the landing terrain.

There is plenty of info published if you want to build your own. A R/E bagged XC is no more work than a DLG, actually easier because you don't have to be so careful with the weight. Full house is more difficult because at the necessary size there is not much extra mass in the budget.

The best way to practice is to fly high and far out with a vario. Get used to flying the tone past where visual tells you what the plane is doing. After that the best way to learn is to hook up with an experienced team. I learned more in one lap with Joe Wurts than I did in 10 years going at this alone. Check the map for a rural location with plenty of choices for landing, and learn the terrain before going out.
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Old Apr 27, 2010, 05:24 PM
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Great suggestions all. Let me add one more critical skill for XC that hasn't been touched on. Learn to fly from a moving vehicle. This may sound trivial, but it really isn't. We normally fly from a stationary point and judge the planes distance, altitude, thermal strength and direction all from a single stationary point. XC is very different where you are almost always on the move. One strategy is to stop the vehicle and only thermal when stationary. Another is to keep the plane in the lift and continue down course with the vehicle. You should practice and be prepared to do either depending on the task and conditions. You don't need an XC plane for this, any decent TD ship will do. The goal is to learn to fly from a moving frame of reference.

A quote about XC flying comes to mind. This is from a number of years ago whe JW had to miss a day of a two day event and had DP stand in for him. His advice, "if it is still visible it isn't high enough". Translation: altitude is potential energy which equals the ability to fly further/faster in looking for the next thermal or ticking off miles.

JT
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Old Apr 27, 2010, 10:54 PM
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Just reading these posts is getting me excited.
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Old Apr 28, 2010, 03:25 AM
the answer 42 is
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Hello all

I had been always enthusiatic about the XC, almost finish my 4m design :P but I had to leave my home country for bussiness reasons and I could no brig it along. Still very interested on this topic, eventhought is now just like a dream for me.

I wish you all success and great flights, hey can someone go and break Joe Wurst XC world record please

EZ

http://aeromodele-vemars.over-blog.c...esriverrc.org/
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Old Apr 28, 2010, 04:00 PM
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Joe W record?

Is it 141 miles?

Tai
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Old Apr 28, 2010, 04:03 PM
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Guys - great advice!
Aeajr - one important aspect also if I may add that differs from normal TD work and I find most frustrating is having the knowledge to look where thermals might be on course. Structures, Alturnating dark/light large ground areas, roads that are not often travelled that allows the heat to build up and release = thermal generators. Practice where you think thermals are compared to where they really are!

The other issue is the plane - I started out with a RnR Synergy 91 wayback when and always completed the short course which was 11k easy - long course was way harder, but the experience gained getting out on course and learning, offsets waiting for that ultimate XC design. Any of the current offerings for TD will work very well. Most of which are already @ 3.7-4m.

jm2c's!
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Old Apr 28, 2010, 05:44 PM
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I can already tell that this is going to be one great thread! Maybe it should have been called "Everything you wanted to know about Cross Country Soaring, but were afraid to ask"! This should turn into a gold mine of information for newbies like myself that have wanted to learn more about this portion of the soaring hobby. As a newbie myself I of course have a couple of questions on several parts of XC soaring.

From reading the posts above, am I correct in thinking that the 2,100 sq/in rule for lifting surface is pretty much out the window? If so, what restrictions if any are there on a XC ship design? I ask because I'm working up my own design for XC but have held it to the 2,100 sq/in rule. If it turns out that I did this out of a misunderstanding on my part, no problem, it would still make for a good plane for LSF level 5 tasks as well as other flying.

Now I know that at times even the best pilot is going to end up loosing lift and going down somewhere along the course from time to time. It it allowed to re-launch and if so what are the rules for it? If re-launch is permitted for the point that the plane went down, how is the re-launch handled? Portable winch? Monster high-start?

Also, could one of the old hands at this type of flying that happens to have it, be kind enough to upload some flight data recordings that could be overlaid in Google Earth? I'd love to be able to track a plane along the course from launch to touchdown. I think that in itself would be a great teaching tool for us newbies.

I'm sure I'll have a lot more questions as time goes along, but this will do for now.

Jeff
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Old Apr 28, 2010, 06:12 PM
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Quote:
Originally Posted by scaflock View Post
From reading the posts above, am I correct in thinking that the 2,100 sq/in rule for lifting surface is pretty much out the window? If so, what restrictions if any are there on a XC ship design?

It it allowed to re-launch and if so what are the rules for it? If re-launch is permitted for the point that the plane went down, how is the re-launch handled? Portable winch? Monster high-start?

Also, could one of the old hands at this type of flying that happens to have it, be kind enough to upload some flight data recordings that could be overlaid in Google Earth? I'd love to be able to track a plane along the course from launch to touchdown. I think that in itself would be a great teaching tool for us newbies.

I'm sure I'll have a lot more questions as time goes along, but this will do for now.

Jeff
I'm sure others will chime in here but here is my 2c. The main design limitation is the 5kg (11 lb) wieght limit. After that is chord and wing loading. If a designer uses the entire allowed wing area (wing plus stab = 2100?? not sure the exact number) I think he will likely end up with a wing that is too large for the 5kg limit (too light a wing loading) and a plane that is too slow and not good in wind. 15+ oz/ft, 12-14" root chord, 11 lbs is pretty much the optimum judging by the SBXC and MXC. Dr Drela may prove this wrong, who knows....

Other than the Thermal Safari, which is an adventure/fun fly not a contest, launching on course is not allowed. The team that lands out must return to the start to winch launch again.

Most of us are pretty new to the GPS flight plots, Google Earth, See You, etc. but we are learning. Last year at Cal Valley the Aloft team supplied all the teams with Magellan Sky Trace GPS units which pretty much got the ball rolling and it really opens up a new and very interesting part of XC racing. I notice RCGroups can take .kmz files as attachments. This is fine for course layouts but my flight data plots are far too large for the 100kb limitation. maybe there is a way around this or interested persons could PM me for the flight plot file. Mine are big but maybe I have my GPS set at too fast a data recording level, still learning. My last plot on the Thermal Safari a couple weekends ago is 588 KB and that isnt even the entire flight as the GPS crapped out 10 miles from my landing point. I think it ran out of memory. I'll attach some plots of our courses which are a small file size.

Steve
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Old Apr 28, 2010, 06:18 PM
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To view a bunch of flight logs on google earth go to: http://soaring.goosetechnologies.com/

Go to the "Current News" at the menu at the top of the page. Scroll down until you get to the "Montague 2009 flight Data" Click on any one of the "KMZ" files and you will see the flight logs on Google Earth.
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Old Apr 29, 2010, 11:20 AM
I need some building time in t
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Am I correct in assuming that the weight limit is ready to fly with all the ballast loaded in etc? I'm also not sure if the lifting area limit includes the tail in the case of a non-lifting type of elevator. Sounds like a little more research on my part is going to be needed.

Even if the design I'm currently working on ends up over the max weight, it will still be something that I could use for fun flying across the desert.

Thanks for the KMZ files too! They should prove to be educational if nothing else!
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Old Apr 29, 2010, 11:42 AM
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Quote:
Originally Posted by scaflock View Post
Am I correct in assuming that the weight limit is ready to fly with all the ballast loaded in etc? I'm also not sure if the lifting area limit includes the tail in the case of a non-lifting type of elevator. Sounds like a little more research on my part is going to be needed.

Even if the design I'm currently working on ends up over the max weight, it will still be something that I could use for fun flying across the desert.

Thanks for the KMZ files too! They should prove to be educational if nothing else!
The aircraft requirements only apply to AMA sanctioned events (and LSF tasks per my interpretation of the rules). They are the same as the FAI limits: all up weight of 5 Kg max (11 lb) and 2100 sq in of total lifting surface. Total lifting surface equals wing plus horizontal tail (regardless of whether it has an airfoil or not, it still is aerodynamically active). For a V-tail I believe the horizontal area is based the projected area.

JT
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