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Old Jun 13, 2011, 07:54 PM
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R2 Hobbies VGA 2M Advance ARF Electric Sailplane...

Anyone have any experience with this bird?
Link: http://www.r2hobbies.com/eng/proddet...pl3901001_code

Seems like there's a 3-Day sale on it for USD $71.14 for members.
Looks like the stab is flat plank on the trailing edge and wing bolts are huge!
However, both stab and wings appear to disassemble for transport which a definite + for me.

There seems to be 4 types of D2836 motors that could work in the $16-19 range and a 40a ESC is about $29.
Spinner and 11 x 6" Folding Propeller are included. Maybe the Passer X powerplant could be used?
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Old Jun 13, 2011, 08:19 PM
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I've got one on the way, after losing my PasserX. The Passer was pretty well made, so I took a flyer on this one. The wing bolts definitely need replacing, and the stab look's a bit crude, as you mentioned.

I think a 2830 motor would be fine in this - it worked well in my PasserX, and is much lighter and less power hungry than the 2836. You'd want a motor that has the fixed portion at the front to mount from the inside of the firewall by the looks of it (at least one of the 2836 motors on R2 is the other way around - might be reversible?), so a motor from the PasserX would work.

I used this one in my Passer X, and it worked fine. 60 degree climb angle, and I could fly all day on a 1000mAh battery. I had to turn the shaft around, which it really isn't designed to do, so there was no circlip holding it together. The prop thrust load pulls it together, and the magnets keep it there.

http://www.rctimer.com/index.php?gOo...1&productname=

I used a 30A ESC, since the current was about 22A if I remember correctly:

http://www.rctimer.com/index.php?gOo...6&productname=

$22 for the power system.

My glider has shipped, but the sale will be over before I see it.

Kevin
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Old Jun 14, 2011, 10:02 AM
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Looks good and for the price, I am buying one as soon as I send this message...

The covering alone would cost me $30.00 + tax for the two colors, so another $40 + $25 shipping isn't too bad ... use it to train my Grandson on R/C flying; also love the wing ribs with material cut out to decrease wing loading ...

...not many birds available for this price and advertised quality!

I just wonder if such a product could be made right here in the U.S. for the same price?

I say put prison workers to work building model planes ... they do the same in China

Gambler
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Old Jun 15, 2011, 10:31 AM
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Purchased. $99.55 delivered + $5.00 off my next order coupon... if it is as good as it looks, great value for an ARF! Thank God we have China!

Gambler
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Old Jun 15, 2011, 02:53 PM
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how does this compare to the passer x?
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Old Jun 25, 2011, 04:40 PM
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R2 Hobbies VGA sailplane ( Need some Help)

Hello,

I just received my 2.0 m VGA Sailplane,it's really really nice,and the covering is flawless. One big problem is it did not come with a build manual. Since this is my first time putting together a ARF plane, a manual would really help. I just e-mailed R2 hobbies about there being no manual. Have any of you guy's put one together yet,that could give me a hand with this?

Thanks,
Craig N
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Old Jul 20, 2011, 06:50 PM
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I finally received my glider yesterday evening, and it is basically ready to fly the afternoon. I still have to work out a hatch hold down, since that is left to your imagination. The weather has gone to crap this afternoon, or I would have taped the hatch on and tried it.

It uses wire and stick pushrods which I haven't seen for years. I guess they will work. There is tons of room in the fuselage. It seems to come out tail heavy even with a 1800mAh battery up front, so I may switch to a heavier motor instead of the recommended Eurgle one. I have to calculate the CG yet, so I'm not sure yet.

The Eurgle motor has lots of power on 3S and the 11x6" prop. I had to sand the motor shaft with some emery paper to get the supplied collet prop hub to hold.

I did find it would be better to connect the elevator pushrod and mount the fin, before hinging the rudder to the fin. I did it the hard way I think. I think they also intended the rudder pushrod to exit on the right side, instead of the left like I did. Not a big deal.

I used a Hitec HS45HB servo on the rudder, and it seems a bit weak for the job. I put a JR SM15 on the full-flying stab, and it seems fine. I may dig through my servo collection and see what else I have. The little 939MG metal geared HK servos are too tall without putting a spacer on the servo tray - too bad, they are the first HK servos I've had other than the HXT900 that I'd trust an airplane to.

The supplied prop blades don't fit the hub (would need washers to take up the extra space at the pivot), so I used some other 11x5 blades I had. They fit perfectly.

The wing bolts are M5's, if anyone wants to replace the ugly stock ones.

You will need a 1.5mm hex key for the fin and stab mounts, and the set screws an the pushrod wire thingies.

It looks like it should be a nice floater.

Kevin
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Old Jul 20, 2011, 10:43 PM
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The CG looks much better than I thought. The swept back wing leading edge and the huge stabilizer deceived me. The neutral point is at 125.7mm back from the root leading edge.

The CG on mine is sitting at 112.5mm back from the root LE with the 1.8Ah battery back a bit from the motor (centre of battery at 100mm in front of the wing LE). This gives me an 8% static margin, which is close to the 7% I usually use. I may switch to a 1600mAh battery, and position it to get the 7% SM.

A better starting point might be a 10% static margin. The CG would be 109mm back from the root leading edge for a bit more conservative CG.

I switched out the HS45HB for a HS65HB. The stronger servo seems quite a bit better on the rudder, although I might be able to lower the pushrod drag out the exit a bit with some judicious bending.

The all-up weight looks to be about 880g with the 1.8Ah battery. This gives a wing loading of about 29.8 g/dm^2, or 9.8 oz/sq. ft.

I'll hopefully get it in the air tomorrow.

The attached drawing shows the aircraft neutral point, and the CG position for an 8% static margin. I can send the CG calculator spreadsheet to anyone who wants it. You can change the weights of components, and see how your CG comes out.

Kevin
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Old Jul 21, 2011, 06:16 PM
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It flies!

I had aligned the stab parallel to the flat portion of the wing saddle, and that is close. I just needed a few clicks of elevator trim. It glided pretty straight on a hand launch.

Th Eurgle 1000kV D2836 motor has tons of power for this glider. I found it is best to launch at about 1/2 throttle, and then feed in as much as you want while controlling the strong nose up tendency with down elevator. It will climb vertically. Programming in some down elevator with throttle would be a good idea, because it wants to loop under power. Launching it at full power turns into a low level, full power loop unless you get your hand back to the stick really fast! The climb rate is very good.

My CG calculations seem about right. I used a 1600mAh battery, and I've ended up moving it to back, and probably will move it some more.

It does very nice thermal turns, and will go round and round hands off, with just some up elevator trim. It doesn't slow down as much as I was expecting. On the other hand it has some legs to move around the sky

The rudder authority at low speeds isn't great. Ponderous might be about right! It only has about 4 degrees of dihedral in the tips, which is pretty low for a rudder/elevator glider. And the rudder isn't big enough. I'm going to try adding on to the rudder, and if that doesn't make it responsive enough, I'll add some more tip dihedral.

It is definitely flyable the way it is, but you need to make careful approaches, and trying to work low lift is difficult. Up high where you don't need to do anything quickly, it is OK, although I've had the stick against the stop more often than I can ever remember today.

I increased the rudder throw as much as I could. I'm on the inside hole of the rudder horn, and 120% on the rudder servo travel. I think more rudder area would be better than more rudder throw at this point.

The elevator is fine, although I ended up on my high rate there as well. I have about 5mm each way, measured at the front of the stab.

I put a tongue at the front of the canopy, and a couple of magnets at the back. That works fine, although a tube and wire at the back would be easier and lighter. My canopy doesn't fit very well, so I may have to add some tongues on the side to pull it in a bit.

Not a bad $70 glider. The PasserX was more fun to fly, particularly with some tip dihedral. It is just a lot more responsive with the ailerons, and with the dihedral I added the rudder worked well too. It is lighter and better for low altitude lift. I'm just spoiled by the discus launch gliders I usually fly.

I almost forgot, the colour scheme is great for visibility. After losing my PasserX, I appreciated how easy it was to see, and the larger size helps with that as well.

Kevin

Edit:

My stabilizer throw is 5mm each way, measured at the leading edge. I edited it above as well

My canopy has now spread out 15mm on each side, after a day in the sun. I think I'll try adding a balsa bulkhead to it, to keep the right shape.
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Old Jul 22, 2011, 09:06 AM
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What did you do for the wing hold down bolts? Those thumb screw bolts were added to the model by someone who does not understand RC!


Edit - R2Hobbies is showing a US warehouse on the web page - how long was that there? I will be keeping a closer eye on them, now. I have a V-tail glider that they carried several years ago and I still fly it quite often after 3 re-builds.
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Old Jul 22, 2011, 09:48 AM
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I just used some 5mm posi-drive pan head steel screws I had in my bin. I'll look for some nylon screws next time I'm in town, but these work fine. The wing boundary layer is quite thick back there, so anything less than maybe 5mm high will be of little consequence.

I have always found the shipping from R2 to be very quick and well packed, and the glider quality is quite good, especially for the price. Plus they have things in stock. My glider took forever, but that was because of our mail strike/lock-out, and the chaos afterwards.

I'm sure if I can get the turn response better on this glider, I will enjoy it a lot more. All the R2 gliders seem to be short of dihedral, although this one has very nice circling behaviour. The wing 1/4c sweep is reasonably high, so that must help with it's dihedral effect. Maybe a bigger rudder will alone will do it.

Kevin
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Old Jul 23, 2011, 07:50 AM
Jack
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Quote:
Originally Posted by kcaldwel View Post
..<snip>... The attached drawing shows the aircraft neutral point, and the CG position for an 8% static margin. I can send the CG calculator spreadsheet to anyone who wants it. You can change the weights of components, and see how your CG comes out.

Kevin
Kevin,

Is your spreadsheet available for a download somewhere? Or if not, can you email it to "jacker at midmaine dot com" please?

Thanks very much,

Jack
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Old Jul 23, 2011, 09:46 AM
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Jack,

I'll try putting the VGA version of it up here as a zip file.

It's not my spreadsheet. It is an excellent CG calculator, and is really handy for positioning equipment and designing as well. Dan (Montag) developed. I really like it. It is available here, with an instruction document:

http://www.rcgroups.com/forums/showthread.php?t=1106300

I doubled the size of the rudder, and hope to give that a try today.

Kevin
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Old Jul 23, 2011, 10:05 AM
Jack
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Originally Posted by kcaldwel View Post
Jack,

I'll try putting the VGA version of it up here as a zip file.

It's not my spreadsheet. It is an excellent CG calculator, and is really handy for positioning equipment and designing as well. Dan (Montag) developed. I really like it. It is available here, with an instruction document:

http://www.rcgroups.com/forums/showthread.php?t=1106300

I doubled the size of the rudder, and hope to give that a try today.

Kevin
Thanks, Kevin. Let me know if I shouldn't make any further use or distribution of that. I just ran it with OpenOffice Calc (don't have Excel) and it runs it fine. Very interesting looking too. I need to go off and study it some more and compare it to some stuff I got out of Sailplane Calc.

Here is a link to a post with the results pages from Sailplane Calc from my Big Blu 96 build. There are also links there for the download on that and for a copy of the RC Sailplane Digest copy that has a tutorial on it. You might enjoy running that your plane if you haven't done that.

This is my first big glider build and first time I used any design aids like these. I am hooked on their value to the getting something flying process!

Jack
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Old Jul 23, 2011, 10:11 AM
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Jack,

I have sailplane calc, but usually use XFLR5 fro anything more complex that Dan's CG spreadsheet will do. The CG calculator is really good, and does wing downwash, CG and wing heights, AVL output (you can fly your virtual plane in CRCC sim!), etc.

Distribution isn't an issue.

Kevin
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