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Old Mar 29, 2012, 11:13 AM
conf user
Joined Jan 2012
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Newbie with a Predator 2, coupla questions

Hi All,
First time glider owner, been flying helis (Outrage 550) for 2+ years, and some fixed wing electrics.

Got the word from CJ, my Predator 2 high wing is on the way! Now I have some decisions to make:
1) servos in wing, or servos in pod ? Pros, cons, what servos to use? My local expert (who hasn't owned a P2, but suggested it for me) says Dymond D-47 in the pod, or Hyperion DS09SCD in the wings.

Am leaning toward the hyperions in the wings, then JR285s for rudder and elevator.

2) what xmitter? I have a Spektrum DX7 I use with the helis. I also have an Airtronics RDS8000.

Am leaning toward using the Airtronics and rig it so the flap control (left stick) is spring loaded to return to "off". Or is it smarter to stick with one radio for all models

Comments and suggestions are greatly appreciated.
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Last edited by freewheel510; Mar 29, 2012 at 09:23 PM. Reason: mistakenly id'd as low wing at first
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Old Mar 29, 2012, 11:25 AM
Jim C
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Joined Sep 2009
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There are pilots here with a lot of experience on those birds. You will get more help. I will put this out there to start.

I would prefer you second servo option. (09 in wings and 285 for tails) I have many rock solid gliders set up that was.

Second, the DX7 is a challenging radio to set up correctly for DLG. It does not have glider type selection and that restricts options. I am not familiar with the other radio. (red pilot)
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Old Mar 29, 2012, 11:30 AM
excelling at mediocrity
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Franktown, CO. USA
Joined Mar 2009
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Welcome to the addiction! I can tell you the DS09s and the 285s are excellent choices and they are the "gold standard" for DLG servos at this time. As far as servo location, there are very few DLGs that don't have the flaperon servos in the wings. Airtronics SD10G would be the transmitter that can handle anything. We have a local pilot that started DLG with an RDS8000 and has since moved up to the SD10G.

John
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Old Mar 29, 2012, 12:13 PM
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Joined Jan 2008
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freewheel:

Servos in the wings are favored, since the conventional wisdom is that the linkages are shorter and stiffer. You also (with the Predator) then have the option to bury a lot of the lingage out of the airstream with either top drive or RDS.

I'm using Hyperions myself, especially for ailerons. Having said that, I have personally installed D-47s in many DLGs, and at all positions. Over forty (40!) at last count. Every single one has functioned in the air perfectly, the whole time I have owned the airplane. Once, I thought one had failed, but it turned out to be a linkage problem. Oh, well.

Yours, Greg
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Old Mar 29, 2012, 12:52 PM
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Joined Sep 2001
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A contrary opinion: The Predator wing is very thin, maybe even thinner than the Zone. I have D-47's in mine (top drive) and they will barely fit.

My take on my low wing Predator, is that lighter is better. Less drag is better. I have JR 285's for rudder and elevator, the D-47's in the wing. If you decide to go that way, I'll share my thought on the servo placement, if you'd like. Is your LWP the regular wing or the cf Dbox?

Walt may have different recommendations.

Gary
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Old Mar 29, 2012, 01:07 PM
Time for me to Fly...
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United States, MI, Fenton
Joined Jan 2000
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I'll second the SD-10G recommendation. I use one and It's an excellent DLG radio. If you ask Finless Bob you hear that it's a fantastic Heli radio too. He even has a comprehensive video about setting a heli up on one. All you have to do is put a rubber band around the throttle stick for flap return when flying your DLG.... And program it properly. I have a trex 450 on a DX7 but this year I plan on switching it over to the SD-10G using the Finless videos as a guide.
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Old Mar 29, 2012, 01:45 PM
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United States, WA, Seattle
Joined May 2011
543 Posts
Freewheel -

Welcome to DLGs! Last summer I put together a low-wing Predator II and have been flying it since. They are great planes, well behaved and good performers, particularly considering the price. A few comments on your questions re: servos and radio.

1) You're probably aware that 4-in-the-fuse is CJ's recommended servo approach for the P2. If you go this route, you'll definitely want to use small servos (like the D-47s or JR188s) as that is a lot of gear to fit in the pod. I believe there are some who have fit 2xd47+2xDS285 in the pod (see the P2 build thread, which is a fantastic resource BTW) but it's not a trivial installation and may even require trimming down the DS285 servo cases.

I went with servos in the wing for the reasons that Greg (glidermang) notes: shorter, stiffer linkages. It also makes wing removal and re-installation a bit less fiddly to have them in the wing since you only have to deal with one electrical connection as opposed to two horn/linkage connections. However, you should know that these wings are quite thin in the area where you are going to need to put your servos, and you will not be able to fit DS09s (or even Dymond D-60s) in the wings without having them protrude (yes, that 1mm of extra thickness makes all the difference). You can get D47s in there with a top-drive setup and have no servo and virtually no servo arm protrude past the wing surface. That's what I did. So if you want to have a clean wing surface and put your servos in the wing, you probably need to go with D47s. For what its worth, my experience with them has been just likes Greg's: they are perfectly reliable, have performed just fine in this aircraft, and they are really small and light. Plus they can run on an unregulated 2S LiPo or LiFe and they are very inexpensive. If I were launching 170'+ and had the room in the wings for it I would go with a different servo, but for the P2 it would be very hard to convince me there was a better solution.

If you go with flaperon servos in the wing, you will have room for whatever you want in the fuse to control your elevator and rudder, except for something like a DS09 which is too tall. I went with JR188HVs, which are tiny, powerful (for their size - not like a DS285 though) and can run on unregulated 2S LiXX packs.

One other side note on wing linkages for in wing servos: you probably want to strongly consider top drive (either the "usual" top drive where the servo arm points to the bottom of the wing and the linkage runs through the interior of the wing, or "easy but draggy" top drive where the servo arm pokes out the top surface of the wing and the linkage goes straight back to the flaperon horn and is fully exposed). This is because your low-wing craft will be really eager to snag anything poking out of the bottom of the wing on the ground when you land it. If your control horns are on the bottom of the flaperons you are very, very likely to catch one on a landing and rip something out. Top drive makes this a non-issue. My P2 is high-wing but I went with in-wing top drive for drag reduction.

2) Transmitter choice: I agree with Jim (ShadowFalken) - the DX7 will be hard to set up in a configuration that is satisfactory for DLG control, although it is possible to come up with a (mostly) usable setup for basic control. I had a DX8 for quite a while and you can make that transmitter work pretty well for DLGs. I've since switched to a Futaba 8FG which is much better for a DLG setup. I'm not familiar with the RDS8000. Bottom line is just about any radio will get you a flyable configuration, but you may have a (very) difficult time making any radio that is not either fairly high-end or glider-knowledgeable do the DLG-specific stuff you want (multiple flight modes with changing camber, trim isolation between modes, momentary launch mode, various surface mixes that are glider-specific, etc.).

Best of luck with all of this - you are asking the right questions and you have made an excellent choice for your airframe.

-John
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Old Mar 29, 2012, 02:34 PM
Blind Hawk
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Seattle, WA USA
Joined Dec 2006
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We missed you at last weekends contest John! Hope you've got the 14th on your schedule.

Just to let it be known, a DX7 can be made to work. I did add a momentary contact button to the back of the radio for my launch preset but otherwise the available programming will work. I've got three flight modes plus launch preset, flaps on throttle stick with elevator compensation, dual rates (which I never use) and snap flaps on a switch. Other mixes are available if you want do do other things. I've never had any issues using the AR6255 RX.

I've had good luck with D47's as well but do know of one case in a friends plane that had stripped gears, likely from a crash.

RdJay
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Old Mar 29, 2012, 07:38 PM
conf user
Joined Jan 2012
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You guys are awesome! Thanks for the great feedback.

I made a mistake in my initial question: it is a high-wing, not low wing P2.

I have to say that short, simple linkages appeal to me, even if they stick out a bit. Unplugging an electrical connection is way better than taking apart a linkage, imho.

Again, thanks for the great help!

Chris
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Old Mar 29, 2012, 07:54 PM
Mickey from Orlando. Really.
Joined Nov 2004
3,579 Posts
Don't ignore the Futaba 3114/54's, that's whats in mine (all in the fuse). I initially worried if they were rugged enough, but no worries. They seem to be the most temperature stable of all my servos with the exception of the JR's.
Too fat to go in the wings, but fit in the fuse nicely.
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Old Mar 29, 2012, 08:11 PM
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United States, WA, Seattle
Joined May 2011
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Quote:
Originally Posted by rdjay View Post
We missed you at last weekends contest John! Hope you've got the 14th on your schedule.

Just to let it be known, a DX7 can be made to work. I did add a momentary contact button to the back of the radio for my launch preset but otherwise the available programming will work. I've got three flight modes plus launch preset, flaps on throttle stick with elevator compensation, dual rates (which I never use) and snap flaps on a switch. Other mixes are available if you want do do other things. I've never had any issues using the AR6255 RX.

I've had good luck with D47's as well but do know of one case in a friends plane that had stripped gears, likely from a crash.

RdJay
Rick,

Yeah, I was pretty bummed to miss the contest, particularly since the weather turned out pretty nice! I'd planned to be there but family commitments once again conspired against it. Will be there for sure at some of the next few.

I'd forgotten that you were running a DX7 - thanks for keeping me honest. I was thinking of a lesser-capable Spektrum TX when I responded (incorrectly) about the DX7.

Chris, I can vouch for the completeness and functionality of Rick's setup - he has indeed figured out how to get just about everything you need for a DLG set up on a DX7 and it works very well. That may be a good solution for your Predator. Sorry for the earlier misinformation.

-John
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Old Mar 29, 2012, 09:29 PM
conf user
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Quote:
Originally Posted by GaryO View Post
A contrary opinion: The Predator wing is very thin, maybe even thinner than the Zone. I have D-47's in mine (top drive) and they will barely fit.

My take on my low wing Predator, is that lighter is better. Less drag is better. I have JR 285's for rudder and elevator, the D-47's in the wing. If you decide to go that way, I'll share my thought on the servo placement, if you'd like. Is your LWP the regular wing or the cf Dbox?

Walt may have different recommendations.

Gary
Considering the D47 is 1 mm thinner than the Hyperion (8 vs 9 mm according to the all-knowing interweb), if the D47 barely fits, that's a really important piece of data!!

I got the regular wing.

Am very interested in your thoughts on servo placement, Gary. And Walt's too.

Thanks!
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Old Mar 29, 2012, 09:53 PM
a.k.a. GlideZilla
Dean.roberts's Avatar
Australia, VIC, Macleod
Joined Sep 2003
203 Posts
I have to disagree...

I've just finished a top drive install on my high wing d-box P2 using DS09s and they do fit. I've put them in the thickest part of the wing and had to take out all of the foam and have them against the top skin.

My kit is over a year old so if the wing has changed since then I take it all back.

The pod build is in progress but I plan to use JR188 for elevator and Futaba 3154 for rudder.

Cheers
Dean
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Old Mar 29, 2012, 09:59 PM
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United States, AZ, Arizona City
Joined Sep 2001
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Chris,
On my wing, the cut out starts at 3 1/2" from the c/l of the wing, If I did another one, I'd put them 2" from the c/l to get a bit more depth. If you haven't joined the wing, then figure out where the thickest part of the airfoil is and put them there. Make certain to put the servos in so that the arm is at the thickest part, which is probably right up next to the spar.

I used the D-47 4 arm horn and cut three off and then used the inner hole on the arm. There are pics of top drive installations in the Predator II thread and also a thread on top drive installations, talking about flap horn lengths. Just going from memory, I think from the bottom skin of the flap to the hole on horn is about 6.5mm, but check those threads. The D-47's don't have the amount of movement that the DS-09's have, so it's important to have the servo horns offset forward about 30 degrees, in order to get enough flap travel. And you could always offset the center more in your transmitter if needed. do one flap before gluing in the servo and check for the correct amount of travel. Not a lot of aileron travel is needed.

I don't think one can beat the Multiplex Evo as a hlg radio. Used they about 150 or less, and there are a variety of 2.4 systems that will go into them. Hitec may even still be installing the aurora module in them, for the price of the module. Opinions will vary.

Gary
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Old Mar 30, 2012, 09:49 PM
conf user
Joined Jan 2012
5 Posts
Predator II has landed!

IT'S HERE!! The mailman brought it today, and it looks really good. Love the packaging, and the colors look good. These wings are LIGHT!! And smooth. I feel as though I could crush the whole glider in my hand. Gonna have to be careful handling this baby.

I've been thinking about the whole radio thing. My current thinking is to use the DX7. It isn't especially for gliders, but I know it pretty well after 2+ years of heli flying. It has four flight modes, each with its own trim settings, curves, aileron etc. (Throttle hold, normal, Idle 1 and idle 2 on helis) . For me, it's the "devil I know", which will be a help learning a new sport. I'll probably set it up in "1 servo" heli configuration, haha. Again, because I understand it's ins and outs.

Current thinking is Dymond D-47s in the wing, and JR 285s for the tail, and a Spektrum AR6200 radio. I'd like to run 2-cell LiFePO4 unregulated, but I don't think the JR 285s can handle the 6.7 or so volts, so I'll probably run 2-cell lipo with a regulator.
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