Foam glider vs. balsa vs. DLG

[joshuabardwell]

I'm always thinking about what my next build is going to be. I'm thinking about a glider lately. I don't have one at all. I'm interested in thermaling. I'd like to try slope soaring, but I don't know of anywhere around me (Knoxville) where one can do that.

I'm considering three options. The first is a foam glider, like the Radian Pro. Actually, the Radian Pro is the only foam glider I've considered. The second is a balsa-based power-glider like the Kunai. Actually, I don't for-sure know that it's made of balsa, but whatever that construction technique is called. The third is a DLG like, possibly the HK Versus.

I think about $200 is a good budget for me, for a PNP model (not counting receiver and battery). All of those planes hit that price point pretty closely.

How does the Radian Pro compare to something like the Kunai? It seems like the Kunai must glide better just by nature of its weight (600 grams vs. almost 1 kg), but the Radian's wing loading is actually a little less than the Kunai (about 7 oz/ft^2 vs. 10). I have heard some people say that foam is just not stiff enough to really glide "well", whatever that means.

What about power glider vs. DLG? It seems like it's always nice to have a motor to pull you out of trouble if you want it. Then again, that weight comes from somewhere. The Versus has a wing loading of only 5 oz/ft^2! That's some good gliding, right there. I also worry that I will be too tempted to fly a power glider just like any other motor plane I have, whereas with a DLG, you've got no options.

IDK... I guess I'm just asking for input, stories, etc... to help me make up my mind.

 

[johnmw]

hi Josh,
obviously, if your area is not that easy to pick up thermal then most likely you will need power/pull to bring the glider up to height.
and if you found that you like gliding, the glider you picked will most likely not gonna be the last one.
just to add to your starter consideration,
there's the FT Soarer w/ power mod or you could even scratch build and heaps fun building..

GL & happy flying!

 

[joshuabardwell]

obviously, if your area is not that easy to pick up thermal then most likely you will need power/pull to bring the glider up to height.

That's a good point. I guess I assumed one could probably find thermals at any field, but maybe that's not true. (Obviously, some days and locations will be better than others.)

 

[RAM]

I did a quick google search, there is a place mentioned north of Knoxville called cross mountain where people slope soar rc
Very old post but I imagine the mountain is still there
http://www.slopeflyer.com/soaring/tennessee/tennesse-slope-soaring.html

 

[joshuabardwell]

I did a quick google search, there is a place mentioned north of Knoxville called cross mountain where people slope soar rc
Very old post but I imagine the mountain is still there
http://www.slopeflyer.com/soaring/tennessee/tennesse-slope-soaring.html

As far as I know, that's the only location in my area. But inspired by your post, I reached out to relaxnfly on RCgroups, who's listed as the most recent contact for that site. Maybe I can get some more info.

 

[Capt_Beavis]

in my limited experience, you won't want to fly the glider like a regular plane. The fun is in seeing how long you can stay up with the glider. A power glider may not be "pure" but it will give you the best opportunity to explore gliding while you are learning to find thermals. You won't have the frustration of trying to and failing to get up to altitude or having to relaunch over and over as you learn to find thermals.

I have only had a UMX radian so value my advice as you see fit.

 

[kwak]

Those 3 planes are different styles of sailplane flying. The Radian will be more laid back. The motor takes you up, you turn the motor off, and soar around. The Kunai is a hotliner. This style can go quite fast and be aerobatic. See the Flitetest Kunai article for video. This style of plane is not going to slow down in thermals as much as the Radian or a DLG. DLG's are great fun, but the challenge is learning to read what the plane is telling you about the movement of the air. It can be quite challenging catching thermals at low altitude but I love this style of glider.

 

[AkimboGlueGuns]

The easiest to get into would probably be the soaring type glider (radian) just because of their ears of use.

 

[joshuabardwell]

The Kunai is a hotliner. This style can go quite fast and be aerobatic.

I'm not sure I understand the point of a hotliner. If you want a fast, aerobatic plane, why build it around a glider?

 

[AkimboGlueGuns]

I'm not sure I understand the point of a hotliner. If you want a fast, aerobatic plane, why build it around a glider?

They tend to be really great low drag airframes with good characteristics. The high lift airfoil also minimizes drag and helps up efficiency.

 

[joshuabardwell]

They tend to be really great low drag airframes with good characteristics. The high lift airfoil also minimizes drag and helps up efficiency.

I guess it's nice to have an aerobatic airframe that you don't have to constantly worry about tip-stalling, or put 500 watts into to get good speed out of.

 

[joshuabardwell]

So then the Kunai and other warm/hotliners are probably out, because I don't want an(other) aerobatic airframe. I have a pretty over-powered Popwing that I do some aerobatics with. Okay, without a rudder, you're not going to do a lot of moves, but I feel like my high-speed/high-power itch has been scratched.

That leaves Radian vs. DLG. And I guess the question of, "Do I want a motor, or don't I," should be pretty easy to answer.

 

[FAI-F1D]

I'm not sure I understand the point of a hotliner. If you want a fast, aerobatic plane, why build it around a glider?

The maneuverability needed for a truly good glider lends itself to some real aerobatics. Hotliners are designed for an incredible level of climb performance because flight performance is dictated by the rules of play--limited motor runs.

Now let's talk turkey about gliders...

There are some nice ones out there. Some are pricey, some not so much. Find yourself something made by Pelikan models, and you'll have a truly sweet machine without paying a firstborn. And that's what I fly. A 1.5m Filip V HLG converted to electric. I stuck a little Turnigy 2830 in it, and with an 11x6 and a 3s 1300, it'll climb better than a Kunai, glide just as well, and better yet, it'll fly for literally over an hour in dead air. With a 3s 500, it'll do the same thing for less time, but it'll glide better than the Kunai *and* still fly longer.

Now, am I saying you have to buy a Filip? Nope. Have fun finding one. But there are other models of the same wingloading that fly just as well. This is where I tell you to go shopping at R2 Hobbies and get a Passer X. It's a 4 channel airplane, light wingloading, gobs of capacity for power. Hobbyking sells a similar airplane. Don't buy it. It's a fine airplane, but the one from R2 is lighter--and it costs less!

Foam gliders fly great. Here's the catch--they don't do so great about making it back from waaay downwind. So you need to figure out what you want--something to ride thermal directly overhead, or something with legs--long ones. For your price range you can get either. Your reason for choosing foam is going to be this: it bounces. Most of the foamies also have more battery space (the Kunai is notorious for being cramped). That said, a good fiberglass fuselage is practically bulletproof, and a careful search can find you a roomy one.

Foamies worth considering: UMX Radian, Radian (not the "Pro" version), Phoenix 2000, and Calypso. Also stay tuned for the new mini from FT, the Tiny Trainer. I've flown it, and it's a sweet flying little plane. With a folding prop, I suspect it would thermal very well. It's a cheap way of getting into gliding, and it's small enough of fly in very tight spaces. On a 3s, it'll climb quite energetically (meaning straight up).

 

[Capt_Beavis]

I thought I had read that the radian pro was a disappointment to many.

 

[joshuabardwell]

Now let's talk turkey about gliders...

Thanks. This is great input.

 

[RAM]

What about a skywalker?

 

[joshuabardwell]

What about this?

http://www.r2hobbies.com/4-channel-rc-ep-1-5m-ag4xxxx-leger-soaring-thermal-dlg-glider-7992.html

Too bad both it and the Passer-X are out of stock. The price on both of them is unbelievable if they include electronics. It's still impressive even if they don't.

 

[dutchmonkey]

I'm not sure I understand the point of a hotliner. If you want a fast, aerobatic plane, why build it around a glider?

also the rc flight speed record last i checked was with a glider at 468 mph.
https://www.youtube.com/watch?v=rfoxjNg-eg0

 

[FAI-F1D]

What about this?

http://www.r2hobbies.com/4-channel-rc-ep-1-5m-ag4xxxx-leger-soaring-thermal-dlg-glider-7992.html

Too bad both it and the Passer-X are out of stock. The price on both of them is unbelievable if they include electronics. It's still impressive even if they don't.

I'd take the Passer. Even though I trust R2 to produce good airplanes, I'm really, really suspicious of off-brand DLG's. That's a whole other class of aircraft, and they have to be built extremely strong and extremely light (no more than 4 oz/sq ft).

The Passer will no doubt come back in stock. If you absolutely can't resist the urge, HK does sell a knockoff that's very good, just a tad heavier (you'd still enjoy it-it's basically a warmliner). Also take a look at the Raptor. It's bigger, so will glide better. My only squawk with it is that weird tail attachment, but it does fly very well based on all the reviews I've seen. Any of the above will have unlimited vertical climb performance with the correct motor.

 

[quorneng]

Just a point but wing loading by itself has little to with gliding performance. It has much more to do with the speed the plane flies at.

Ridge soaring and thermal soaring require different types of glider, flying techniques and understanding of the weather conditions although within limitations the same type of glider can do both.

Whether you build or buy RTF is up to you but don't discount anything just because it is plastic. Every high performance full size glider is!