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Old Jul 20, 2012, 01:05 AM
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Tuomo's Avatar
Jyvaskyla, Finland
Joined Aug 2003
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Quote:
Originally Posted by ak79 View Post
So here is a thought,

My 3.5 can only reach 77 oz with max brass ballast.

My old 3.5 was 80oz empty, and flew well with ballast, so I'm left thinking that I need to be able to carry more. I don't think 77oz is that great if the wind really picks up. I would like to be able to get it near 85 or even 90.

Thoughts?
90oz is not that much if wind really picks up. Not even in 3.5m plane.

My friend is quite happy with his (old and heavy) Xp 3.5 (the original airfoil). Flyes nicely in wind with full ballast. If I remember right, the plane weights 2.25kg empty (about 80oz for you).
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Old Jul 20, 2012, 01:17 AM
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United States, CA, Torrance
Joined Apr 2006
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Quote:
Originally Posted by Tuomo View Post
90oz is not that much if wind really picks up. Not even in 3.5m plane.

My friend is quite happy with his (old and heavy) Xp 3.5 (the original airfoil). Flyes nicely in wind with full ballast. If I remember right, the plane weights 2.25kg empty (about 80oz for you).
Exactly! So is NAN going to make some uber ballast for us??
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Old Jul 20, 2012, 01:29 AM
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Jyvaskyla, Finland
Joined Aug 2003
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Quote:
Originally Posted by ak79 View Post
Exactly! So is NAN going to make some uber ballast for us??
When Xplorer was designed the std lay-up 3.8m weight was 2.2kg. Current ballast system is ok for that weight.

Most top competition pilots have stronger planes for high winds. I have seen double carbon Xplorers, they are very nice and strong. With current technology weight is actually quite low, maybe even as low as 2.2kg, and stiffer wings give some extra altitude in launch.
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Old Jul 20, 2012, 08:09 AM
Daryl Perkins's Avatar
United States, VA, Falls Church
Joined Mar 2007
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Quote:
Originally Posted by Larry Jolly View Post
David,
The mimimum sink or best sink rate for the X2 is with TE dropped 6mm. LJ
Do you know how was this determined, LJ? That seems excessive for any section. Sometimes what feels nice and buoyant, adds drag and increases sink rate.

In this day and age of proprietary airfoils, without the coordinates, we are unable to do any computer analysis and come up with our own solutions.

I recd a 4.0 X2 a week or so ago. It is not full strength, but it finished out at 53.23 ounces. Covers ground amazingly well for its weight, as well as or better than my 67 ounce X1. It's a really fun chuckie.

And before you guys start disbelieving my AUW, I weigh the components on our scale at work that is accurate to 1/10th of a gram. I must have weighed this thing 5 times, thinking I forgot to weigh something, cuz I didn't believe it either.

See ya in SA

D
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Old Jul 20, 2012, 10:33 AM
or F, J, K, or even TD
FLY F3B's Avatar
Joined Jun 2007
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53.23oz

That is freakishly light.

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Old Jul 20, 2012, 12:00 PM
Win=span\massXpractice+lu ck
webbsolution's Avatar
Joined Jul 2007
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Quote:
Originally Posted by Larry Jolly View Post
David,
The mimimum sink or best sink rate for the X2 is with TE dropped 6mm. The real advantage of the X2 is not it's minimum sink rate but it's ability to come home.
Make sure you are practicing flying in wind and get a real plan on how far out you can venture and still make it back. The field in SA is nearly featureless for kicks and will likely be cold and windy.. The perfect combination for broken hearts and long retrieval walks... LJ
Thats an interesting TE # -

We flew in every windy day that presented itself to us this spring and summer - I cant say it was a lot of days but what I can say is that I have a far better idea of when to ballast and when to add 880gr of tungsten rod to the full strength variant of my X2's - If it howls its going to be a stressfull event but at this point ill take what it throws at us.

Now if flying in rain was of value then the Canadian team has everyone beat. We have been doing our last two launch days from underneath tarps just waiting for a window to launch...seriously wet weather this summer in BC.
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Old Jul 20, 2012, 04:10 PM
F3B and F3K
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United States, TX, Dallas
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Originally Posted by webbsolution View Post
Now if flying in rain was of value then the Canadian team has everyone beat. We have been doing our last two launch days from underneath tarps just waiting for a window to launch...seriously wet weather this summer in BC.

Dave,

What surfactant are you guys using when flying in rain?

Just don't say you don't use anything, because then you will very likely get burried against the germans and other soaring powerhouses in rain.

Best,
Reto
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Old Jul 20, 2012, 06:29 PM
Win=span\massXpractice+lu ck
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Joined Jul 2007
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Quote:
Originally Posted by RetoF3X View Post
Dave,

What surfactant are you guys using when flying in rain?

Just don't say you don't use anything, because then you will very likely get burried against the germans and other soaring powerhouses in rain.

Best,
Reto
I typically put a coating of protectall on the wings. Its lite and a single application seems to last for a week or more. Not having much data to compare against all I was really concerned about was that the water beads up and comes off.

I just worked out the wing loading of the 3.8 X2 SL (6.13) vs my 4.0 Sl (6.68) vs my 3.5 SL (6.77) they are all so close now.
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Old Jul 20, 2012, 10:52 PM
F3B and F3K
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United States, TX, Dallas
Joined Mar 2009
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In F3B it makes quite a dramatic difference if you prevent raindrop formation on your wing or not. Speed runs get really sluggish with rain drops and look like in slow motion with the handbrake on. A surfactant also helps in distance in rain, maybe 1-2 laps on a 20 laps pace.

This should all also translate into F3J (zoom in launch, legs) and I know some of the germans work with it for years.

Good luck in SA.

Best,
Reto
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Old Jul 20, 2012, 11:00 PM
Win=span\massXpractice+lu ck
webbsolution's Avatar
Joined Jul 2007
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Quote:
Originally Posted by RetoF3X View Post
In F3B it makes quite a dramatic difference if you prevent raindrop formation on your wing or not. Speed runs get really sluggish with rain drops and look like in slow motion with the handbrake on. A surfactant also helps in distance in rain, maybe 1-2 laps on a 20 laps pace.

This should all also translate into F3J (zoom in launch, legs) and I know some of the germans work with it for years.

Good luck in SA.

Best,
Reto
Thanks Reto,

I hope the potential for rain in africa is low...

Back home its quite high still...we havce basically this weekend - next saturday and thats about it for test launches and fine tuning -

I am more worried about connecting in the UK than the prospect of rain...London sounds like a madhouse with the Olympics at the moment.

I just installed ribs to tie my servo into the bottom skin on all 5 planes! I still have to finish the servo covers but im beat and they can wait.
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Old Jul 21, 2012, 01:11 AM
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Tuomo's Avatar
Jyvaskyla, Finland
Joined Aug 2003
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Quote:
Originally Posted by RetoF3X View Post
What surfactant are you guys using when flying in rain?
I think the std practice is to wipe some soap (or shampoo) over the wing. Prevents water forming into drops.

Water affects not only high speed performance. I floating type of raining weather (not so uncommon in autumn) it is best to keep a little more speed and less camber than usual. If you force a plane with wet wing to fly at very slow airspeed, it will come down very quickly.

I have not noticed much difference if launch. Obviously there is a difference. However, in F3J the most relevant launch problem are the bowmen, slippery when wet
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Old Jul 21, 2012, 08:09 AM
F3B and F3K
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United States, TX, Dallas
Joined Mar 2009
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Lol, good point with the towers, Tuomo. About the zoom: Dive a plane while flying in rain: it will not pick up any speed and fly suggish with raindrops on the wing. Since the zoom is essentially the inversion of a vertical dive, it will suck too. Maybe more apparent in B but still.

Don't fool yourselfs, since the rainy F3B worlds in Switzerland, most teams have realized that it is important to practice in sh*&6t weather, because there is much to gain (or lose) in ugly weather.

I had earlier made the mistake to practice only when it is nice outside. It needs some encouragement to go practice when it pours, but it pays off...

Reto
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Old Jul 21, 2012, 10:25 AM
Registered User
Joined Apr 2012
14 Posts
1500 grams?
You used to be cool Daryl when you flew planes at 4kg and 14 sec in south Africa...
Now your going back again to defend the tittle you won there over 10 years ago to fly a plane 1500 grams for 15 minutes....
How times change...

Just remember not to take your mobile phone to the dinner if you win...
They don't like to swim. ;-)


Quote:
Originally Posted by Daryl Perkins View Post
Do you know how was this determined, LJ? That seems excessive for any section. Sometimes what feels nice and buoyant, adds drag and increases sink rate.

In this day and age of proprietary airfoils, without the coordinates, we are unable to do any computer analysis and come up with our own solutions.

I recd a 4.0 X2 a week or so ago. It is not full strength, but it finished out at 53.23 ounces. Covers ground amazingly well for its weight, as well as or better than my 67 ounce X1. It's a really fun chuckie.

And before you guys start disbelieving my AUW, I weigh the components on our scale at work that is accurate to 1/10th of a gram. I must have weighed this thing 5 times, thinking I forgot to weigh something, cuz I didn't believe it either.

See ya in SA

D
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Old Jul 21, 2012, 11:36 AM
that's gonna hurt...
USA, CA, San Jose
Joined May 2005
1,109 Posts
Still waiting for a X2. Guess I should have moved to Jamaica and tried out for the Jamaican F3J team

Bruce
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Old Jul 21, 2012, 12:48 PM
Always more to Xplore
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near Sacramento, CA
Joined Aug 2010
783 Posts
Quote:
Originally Posted by Tuomo View Post
I think the std practice is to wipe some soap (or shampoo) over the wing. Prevents water forming into drops.
Tuomo, I wonder if anyone has tried Rain-X glass treatment? It's a super effective spray-on wax for car windows. The water beads so well I no longer use windshield wipers when I'm at driving speeds.

And don't forget Rain-X De-icer for those high alt thermal flights

Chris B.
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