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 Are you flying 2.4 GHz for Composite Sailplanes?
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aeajr

476 Posts

Posted - 04/12/2007 :  4:53:24 PM  Show Profile
SAILPLANES

This goes out to all the people flying sailplanes on 2.4 GHz

I am asking for your experience to date. My friend is ready to buy a new radio system and has asked for my advice. I hink the DX7 is the best that is available today in a 2.4 GHz system for his needs and budget. The new 9303 2.4 GHz looks good but too expensive and not available till summer.

He flies

1) Fred Sage Compulsion 3M full house glider. - This links if for a Thermal Dancer, not the Compulsion, but they are similar in look and construction
http://polecataero.com/products/thermal-dancer

This plane needs about a mile range for competition thermal duration contests. Will the AR7000 receiver get the job done? Can the AR6100 micro receiver do it?
There is no motor in this plane.


2) XP5 DLG is a 60" DLG - carbon/kevlar fuselage
http://www.polecataero.com/products/xp-5/-
Will the AR6100 work in this plane? Figure he will need 2500 foot range tops.

His other planes are foam and smaller so not an issue for them.

What experience do you guys have?

Is the DX7 ready for these composit planes or should I direct him to stay with 72 MHz for now?

Best regards,
Ed Anderson
ESL Content Editor
aeajr on the forums

Edited by - aeajr on 04/17/2007 08:08:54 AM

dbeach

46 Posts

Posted - 04/13/2007 :  08:52:16 AM  Show Profile
Ed,

Unfortunately I don't have any first hand experience with 2.4GHz and sailplanes. I'm quite interested, and have been following a somewhat informative thread on RCGroups (see http://www.rcgroups.com/forums/showthread.php?t=657685).

My personal stance is 2.4GHz is good for wood and fiberglass, and I'm waiting for more actual success stories before attempting use in a composite ship.

I would advise either deferring purchase of a new radio, or looking for good bargains in used fixed frequency equipment.

David
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aeajr

476 Posts

Posted - 04/13/2007 :  09:06:10 AM  Show Profile
Dave,

Thanks for the link. In fact that discussion was brought to my attention last night.

Another group thread is looking at the effects of carbon fuse.
http://www.rcgroups.com/forums/showthread.php?p=7257327#post7257327

I think these 2.4 GHz systems are very exciting. I think they will also influence the materials we use in fuselage construction. I would be we start to see more kevlar and less carbon in these high strength fuselages just so they will work with 2.4 GHz systems.

I can see it now. Big banner .... THIS PLANE IS 2.4 GHz FRIENDLY!

Here is a summary of what I have been reading about the Spektrum DX6 and DX7 and their receivers over the past 6 months, and especially the past few days. This is all in relation to pure gliders and small electric planes, say in the speed 400 class and below. Seems the main range issue is around the size of the motor and battery pack in non-carbon and non-metallic planes.

AR6000 micro receiver - The Spektrum AR 6000 receiver that comes with the DX6 has been shown to be very reliable out to about 2500 feet in wood, foam, plastic and fiberglass. I imagine Kevlar would qualify as well. Tests still hold up at 3000 feet but after that it gets shaky. So I use 2000 feet as my save for electics and 2500 for pure gliders.

I have been telling the new pilots in the club with DX6 that they should be OK with an Easy Glider, and a 2M non-carbon plane, but no bigger. Should be fine for DLG with non-carbon fuselage.

The DX7 has a higher power output than the DX6, so the AR6000 may have even better range when used with the DX7. It might be ok in a 2.5M non-carbon plane.

The DX7 micro reciever, the AR6100, seems to have a bit less range than the AR6000 but is probably still good to 1800 feet, so an Easy Glider, or similar sub 2M plane is still probably OK but I would not go to a 2M plane if you plan to push out far. Should be fine for DLG that does not have a carbon fuse.

The DX7 with the AR7000 is claimed to be good as far as you can see it. Tests show it does suffer from carbon fuselage but not as much as the micro receivers due to its remote/dual receiver design and 4 antenna.

If you have a wood, glass, foam or kevlar fuse you can probably put this out as far as you like with confidence. It may even be able to take most carbon planes out 3/4 of a mile or further, but that is just conjecture on my part, based on my readings.

I imagine a carbon wing could cause momentary loss of signal on a turn but I don't see it being a problem, especially with the AR7000 and its remote receiver design. It would be more of an issue with the micro receivers and their smaller view of the world.

I am going to continue my research and will continue to post findings here for the benefit of everyone. I hope you and others do the same.

Best regards,
Ed Anderson
ESL Content Editor
aeajr on the forums

Edited by - aeajr on 04/13/2007 09:29:54 AM
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aeajr

476 Posts

Posted - 04/30/2007 :  02:48:32 AM  Show Profile
Nice Demo of 16 Spektrum DX7s flying shoulder to shoulder. Not sailplanes but a nice demo none the less.

http://www.rcgroups.com/forums/showpost.php?p=7365739&postcount=2086

Best regards,
Ed Anderson
ESL Content Editor
aeajr on the forums
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mikel

106 Posts

Posted - 06/24/2007 :  10:02:54 PM  Show Profile
I flew my 1/3 scale Salto for three days at the JR Aerotow with a Spectrum DX7 and AR9000 receiver. I also had one of the monitors in there that can report how many errors each receiver sees and how many frames of data were lost in during the flight. I had some flights that lost around 40 frames of data in over 30 minutes of flying. That includes some pretty high altitude flying as well as flying far out to the horizon. It's easy to get farther out than you would in a normal TD ship when you have 5.2M of wing and a nice wide root chord and fat fuselage to look at. The receiver was located pretty close to the wing rod. That goes through an aluminum tube in the fuselage and the diameter almost exactly matches the lengths of the antenna on the RX. Plus the wheel was located just below the RX. That's probably about as bad a place as you can get in that sailplane for the RX. But that is were the old R2000 synthesized RX was placed and I didn't have any extensions to move it anywhere else.
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aeajr

476 Posts

Posted - 06/25/2007 :  02:43:13 AM  Show Profile
Mikel,

I dont' know that plane. What is the material make-up of the Fuselage?

I believe the AR9000 is a two piece receiver, where did you have the two pieces? Did you have any problem placing it?

If I understand frame rates on these receivers, 40 frames in 30 minutes would be near perfect. Would that be correct? Unless they were all together, you probably couldent even tell that anything was lost. Would that be correct?

Thanks for info you can provide.



Best regards,
Ed Anderson
ESL Content Editor
aeajr on the forums
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aeajr

476 Posts

Posted - 06/25/2007 :  03:08:45 AM  Show Profile
Here is a thread I started on RCUniverse with a similar title:
http://www.rcuniverse.com/forum/m_5738685/tm.htm



For anyone interested, here are product information links on 2.4 GHz products followed by threads that discuss those products with actual field results.

Spektrum RC
http://www.spektrumrc.com/DSM/AirProducts.aspx

JR Radios - 2.4 GHz
FWIW, JR has alligned with Spektrum as their Standard
http://www.jrradios.com/Articles/HobbyWire.aspx#HobbyWire823

Spektrum DX7 - Actual Field Results
http://www.rcgroups.com/forums/showthread.php?t=604621



Xtreme Power Systems - Power Link
Modules for most transmitters
http://www.xtremepowersystems.net/

XPS Actual Field Results
http://www.rcgroups.com/forums/showthread.php?t=671388



Futaba 2.4 GHz
http://2.4gigahertz.com/

Futaba Actual Field Results
http://www.rcgroups.com/forums/showthread.php?t=640656



Best regards,
Ed Anderson
ESL Content Editor
aeajr on the forums



Edited by - aeajr on 06/25/2007 08:06:58 AM
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mikel

106 Posts

Posted - 06/29/2007 :  10:30:35 AM  Show Profile
Salto is a scale sailplane. The fuselage is fiberglass. It has a huge wing joiner rod going
through it. The joiner rod is about 1" diameter. There is an aluminum tube that the rod
goes through in the fuselage. I have a tray in the fuse that is just below that tube. And
the wheel is located below that tray. So I placed the AR9000 main RX right there in the
middle. Above the wheel, slightly behind the wing rod with one antenna actaully starting to
go under the wing rod. So in a thermal bank turn, there are angles where the rod would
be between the transmitter and the antenna.

There are two receivers in the main unit. I had one remote receiver 9" away on the side of
the fuselage in front of the wing rod. So it was pretty clear of any potential objects that
might cast an RF shadow.

The 40 frames in 30 minutes is pretty good. I had some flights on Saturday where we could
only tow to about 1500ft. Lots of clouds so the air was nice for gliding, decent flight
times even from that altitude, but lift normally was not strong enough to get up and risk of low level clouds getting between pilot and plane kept things close. On those flights, I had 0 frames lost in typically 12-15 minute flights.
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mikel

106 Posts

Posted - 06/29/2007 :  10:33:12 AM  Show Profile
I have also been using AR7000's in my Bubble Dancer and one of my F3b ships. Both use the same shape pod. Same as Tom K uses for his Supra. Front RX is in same place normal RX would be. Remote RX is back a few inches with antenna parallel to bottom of fuse. Seems to work fine. I've used plug-in module with my 10X for the F3b ship and DX7 for the Bubble Dancer.

I have also flown the bubble dancer with ballast bars installed. The ballast bars are in the fuse and sit next to the receivers. Bars are about a foot long. I've flow it with both aluminum and brass bars installed. Haven't tried the tungsten one. Don't normaly need 24 oz of ballast .
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mikel

106 Posts

Posted - 06/29/2007 :  10:35:39 AM  Show Profile
If the AR7000 still seems a little large, you can now get an AR6200 which looks like the 6100 except it also has a remote RX like the 7000. That should work for anyone using a 9303 on 2.4 in a 6 servo model.

For the truely paranoid, I would use an AR9000 with one remote RX in the fuse and another
remote RX mounted in the wing, probably next to the flap servo.

Or you could just reverse the normal way of doing things. Put your 4 servos and receivers in the wing and just run wires into the fuse for the tail servos and battery connection.
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aeajr

476 Posts

Posted - 06/29/2007 :  11:51:16 AM  Show Profile
Thanks for sharing your experience. Sounds like 2.4 GHz has worked well for you.



Best regards,
Ed Anderson
ESL Content Editor
aeajr on the forums
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cluft

14 Posts

Posted - 06/29/2007 :  12:52:51 PM  Show Profile
I have just installed the Xtreamlink system in my Jr XP8103 and SuperV.

I mounted the receiver so the antenna sticks out of the canopy about 1 inch forward from the back end. I just completed a range check were I positioned the plane standing on it's nose, looking at the bottom of the plane. Thats the worse position for the receiver because all the planes electronics and carbon fiber is in the way.

I was able to get the distance recomemded with the TX antenna removed and power level set to low, following the manufacturs procedure.

When using the system, there's no jitter or glitching that I would get when on 72Mhz. I do have a flap servo that buzzes in a certain position and that has quieted down. You would think the plane was turned off until you move a stick and it moves

I hope to get out and fly it this weekend.

Carl Luft
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aeajr

476 Posts

Posted - 06/29/2007 :  9:04:01 PM  Show Profile
Any chance you have a picture of the install?

Why do you have the antenna sticking out?

Best regards,
Ed Anderson
ESL Content Editor
aeajr on the forums
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cluft

14 Posts

Posted - 06/30/2007 :  01:16:14 AM  Show Profile
Here is 2 pictures


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cluft

14 Posts

Posted - 06/30/2007 :  01:19:31 AM  Show Profile
I uploaded two pics but I don't see them
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aeajr

476 Posts

Posted - 06/30/2007 :  07:19:24 AM  Show Profile
The max picture size you can put on a post is 250K. Is it possible that they were larter than that.

Best regards,
Ed Anderson
ESL Content Editor
aeajr on the forums
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cluft

14 Posts

Posted - 06/30/2007 :  08:15:09 AM  Show Profile
one was 15K and the other was 18K jpg's
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F3jeb

103 Posts

Posted - 06/30/2007 :  10:36:35 AM  Show Profile
Your files are making it to the server, the links are not being transfer to the body of your message, that is usually a browser issue, if you use IE on windows it should be fine

Image Insert:

11.22 KB



Image Insert:

19.01 KB
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cluft

14 Posts

Posted - 07/01/2007 :  04:24:58 AM  Show Profile
Thanks for getting those pics up.

As for why I mounted the receiver so the antenna sticks outside the canopy, It was the quick and simple way to mount the receiver without changing things around inside the fuse. the area were the receiver is was an empty space and the antenna needs to have clearence from any metal or carbon fiber or wires. A block of foam holds the receiver up against the fuse.

The best place for antenna performance would be to mount it sticking out the bottom of the fuse. after all, your looking at the bottom of your plane when your flying it. That would be kinda hard on the antenna when landing thou.

I'll pass along a flight report when I have something to report

Carl
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mikel

106 Posts

Posted - 07/03/2007 :  08:54:50 AM  Show Profile
I have been doing more testing with a Spectrum module in my 10X transmitter and the R9000 receiver in my F3b/Unlimited models. The nice part about this RX is you can plug in a widget that tells you how well each receiver is doing, how many frames were lost and if you had any holds.

I've done some flying that is similar to F3j early morning / late evening flying which means sticking with light air a long way down wind without much altitude or cuising out a long way.

I haven't had any holds. And obviously, the number of lost frames of data goes up the
farther out you fly at low altitudes.

If I slide my remote RX back in the fuse to the pylon area, the amount of signal loss
does get higher. That area is all carbon. Performance further up where there is
just uni-carbon on the sides is pretty good.

Next thing I'm going to do is get an additional RX mounted in the wing to compare with
the fuse mount RX.

At least I don't have to thin about carbon booms any more. No antenna back there...
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mikel

106 Posts

Posted - 07/07/2007 :  8:31:27 PM  Show Profile
I flew 2.4 at Daniel Boone contest today, what were you doing?
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