Parkzone Radian RTF CG way out of whack

[Rockin Robbins]

You'll learn to fly the climb by airspeed. Pick your throttle setting du jour. Take half throttle for early flights. Launch level and pull up smoothly into the climb with your elevator. You'll need some down elevator to keep the climb angle steady. Now you gauge your climb angle by airspeed. Going too fast? Increase your climb. Slowing down too far, shallow out that angle. Keep enough speed where the plane feels rock steady.

My very first flight with the Radian I decided I was just going to do a test glide. I tossed it out there power off, which I recommend to all new pilots (toss, then add throttle and pull up into the climb). But the power off glide was so great I just dialed about a third throttle and took her up in a shallow climb to about 50 to 100 feet. I shut down the power and flew a large circle around myself while learning the speed it likes to glide, playing with the trims to eliminate any porpoising or directional issues. Then I just took her down for a landing.

My second flight was my first sailplane style climb-out. I benefited from flying a sailplane with a high start 20 years before and a powered launch was uncannily like a high start launch was. There just weren't any surprises other than how powerful the Radian motor really is. So I really cheated.

[xmech2k]

Not to take away from your advice Rockin, but I wouldn't recommend flying circles around yourself, especially when you're that new. Disorientation, tripping, dizziness... Although I could see where it might possibly help with airplane orientation, but I think the other problems outweigh that.

I wonder, Tsheffel, have you had any RC simulator time at the computer? Very helpful to get the feel of things.

[tscheffel]

@xmech2k: I have a dozen or so hours on the Real Flight demo. It was very tough at first but it's fairly easy now (the reverse spatial view is not a problem for me). This was via keyboard/mouse only though. And as with most video gamers, I've flown far too many hours on PC flight sims, not that that helps any at all but I have a decent understanding of flight mechanics (for a rookie).

During my initial outing (2 brief flights), I kept the plane downwind of me since I didn't want to overfly my kids. Unfortunately, I stood about 75' from a tree instead of walking farther out in the field (it was really cold and the nearby picnic table provided a good workbench and place for the kids to sit instead of on the snow). I won't make that mistake twice.

[hayofstacks]

Not trying to take away from anything, but I had quite a bit of virtual stick time, in flight sims, real flight, plus many others. My own honest opinion, without a real plane in the air, its just going to help you with orientation and getting familiar with the controls. You only have half of that where you were using a keyboard.

Just get it up nice and high, avoiding stall, keep it down wind, and practice cirlces. The rest will come natrually, especially if you were able to mmake two short flights, and still have a plane to show off.

Your elevator trims will change with airspeed and throttle. You should trim it by getting it level, in a glide with power off, give it a couple of clicks of up/down trim until it starts keeping level.

Everyone is making way too big of a deal about you being slightly nose heavy, for now, this is what you want.

Check your control surfaces before takeoff, get it nice and high (where you can still see it) and get some stick time in. Practice being smooth and keeping the wings level, and how elevator and rudder effect your speed and stall. Leave the motor constant for now, at least until you get up a ways. Then you can start screwing around a bit, and having some fun.

[hayofstacks]

Also, where are you located? Maybe a fellow wattflyer is within driving distance, and could help you with setup and maybe even a buddybox/trainer type of situation.

[xmech2k]

[QUOTE=tscheffel;894560 And as with most video gamers, I've flown far too many hours on PC flight sims, not that that helps any at all but I have a decent understanding of flight mechanics (for a rookie).[/QUOTE]

I've flown Microsoft Flight Simulator, X-Plane, and a few others since I was in High School. (That was Flight Simulator v1.0, before Microsoft bought it! A long tim ago, in a galaxy...) So when I finally got an Apprentice about 5 years ago, I soloed on my 2nd flight, only nicked the prop and landing! So I fully believe all that stuff helps. True, it's not quite the same, especially no pucker factor, but it can go a long way in someone's training. Flying keyboard though, that probably limits the things you get out of it.

You'll get it! Just don't give up!

[Rockin Robbins]

The Radian is a 3-channel plane which makes no apologies to 4-channel planes in the flying bag of tricks department. Would you believe the plane is capable of rolling circles while executing beautiful axial rolls? And now for your listening and dancing pleasure:

Knuckleheads - Parkzone Radian EP R/C Sailplane

[CrimzonRider]

Originally Posted by hayofstacks

.... keep it down wind, and practice....

IMO..... with e-gliders and a stiff Oklahoma-type wind....keep it up wind.....if your downwind and hittin' LVC is a recipe for a whole lotta walkin'..... and finding only peanuts!!!

cr
good to see another radian thread!....subscribed.

[hayofstacks]

True... ment upwind... has not been a good day for me I guess...

[CrimzonRider]

No worries....I've been corrected many times ....lol....just wanted to give the new guy the bestest chance....plus tomorrow is FRIDAY!!!

have a good one
cr

[JetPlaneFlyer]

tscheffel,

You are probably snowed under with advise now but I'll add a few of points of my own that may have already been mentioned but are worth reiterating.

1. Don't fly on full power, it makes the plane much 'twitchier' on the controls and flying fast gives you less time to think. Just climb away gently on part throttle. The throttle stick in the middle is enough on many planes for a gentle climb out.
2. When you are learning NEVER fly downwind. If you are downwind and you have a momentary loss control the wind takes the plane away from you and very quickly you loose all orientation. ALWAYS fly upwind, fly with your body facing the wind and keep the plane in-front of yourself at all times.
3. Don't fly over your head, this causes loss of orientation. You may find it helps to twist your body so that you are facing in the direction that the plane is flying, this helps avoid the perceived control reversal issues when flying toward yourself.
4. Don't fly if the wind is any more than a gentle breeze (maybe 5mph). In fact is you can it would be best to wait for a virtually flat calm day.
5. Use low control throws. If your Tx has rates set them to about half of the movement quoted in the manual. Planes like the Radian are very stable and if trimmed will fly perfectly well by themselves. It takes someone over-controlling them to make them crash! When the plane is trimmed you should be able to gently steer it around by almost breathing on the controls. Don't start 'chasing' every movement of the plane with big inputs on the sticks. This leads to a phenomena known as 'pilot induced oscillation' which is probably what caused your loop.

[tscheffel]

Many thanks for all the additional advice (especially JetPlaneFlyer's point #2--makes sense, now). I now need to put the newfound knowledge into practice and roll the dice.

I believe I have corrected the CG issue. I whittled away a bit of foam so I can nestle the battery a bit farther back into the fuselage. The stand shows the plane's CG to now be at the recommended 2.5"/63mm mark from the leading edge. I also added transparent duct tape to the leading edges of the wing and tail (before correcting the CG).

Now all I need is a sunny Saturday with calm air (a higher temp would be nice, too).

@hayofstacks: I live just north of Rockford, IL. There are several quality RC clubs near me, and I plan to join one of them soon. It might be my German pride/stubbornness but I am determined to tame this beast on my own before taking the logical step of getting face-to-face assistance. The journey is the reward.

[Fig]

There are a lot of good recommendations here. Rockin Robbins and others are dead on. What I didn't see mentioned, but alluded to in Rockin's post is that this plane as most gliders I have flown seem to be a couple of seconds behind your controls. That's because of the way it is designed. You have to plan your moves carefully when flying this plane and be a couple of seconds ahead of it in your inputs. That being said, while the plane is under power it's a different ballgame and the trick is making the switch from powered to non-powered flight, which Rockin Robbin covered above.

One other thing I would suggest is find an area away from trees. Rc planes and trees are like trailer parks and tornados.

1) Launch with less than full power and use the controls to keep it from going completely vertical. My Dad's radian will literally go straight up if you don't keep the nose pushed down. Do not make any trim adjustments when under power.

2) Get it as high as you are comfortable with and try to level the nose as much as you can and power off the motor. I usually am forcing the nose down at this point trying to keep from stalling.

3) Once it is in glider mode note that everything goes into a slow motion. All control inputs are much slower to see the result (unless you have the airspeed way up). Let the plane settle into a glide and then start trimming it out to eliminate porpoising and any wandering left or right. One last note on this, you want to make sure you trim the plane facing upwind. I spend 80% of the flight facing upwind using downwind only to make a circle so that I can get back to gliding. Knowing which way the wind is blowing is key to RC flying, but a lot more essential for a glider. Be prepared as well for a shift in wind direction as you get to various altitudes. This plane has the capability of becoming a dot in the sky pretty quickly. For now don't go too high but make sure you are gliding into the wind. Learn to read the glider and she will tell you which way the wind is blowing up there.

4) Once the trim is established, make a circle and note that the downwind ride is going to be different as far as trim and handling go, it all depends on the wind speed. I don't adjust my trim settings on downwind runs, just use the sticks to get the plane back to where you can get into glide mode again.

5) Start planning out your landing strategy. I sometimes make a landing run a couple of mistakes high just so I can get an idea of how it's gliding before getting close to the ground. The more you fly your plane and the more experience you build up this won't be as necessary, but for now, make a test landing run a couple circles up so you know you have enough room.

6) Once you are ready to land make the circle like you practiced and keep everything smooth as you approach the ground. Don't be afraid to abort the landing and apply power, but be prepared for the change in the way the plane reacts to input under power. You have to mentally go from slow and easy to hands on flying.

Since you are a beginner I can't stress enough that you need to really hold out for calm days. Resist the urge to "just get in a quick run" with it really windy. You will be rewarded for your patience.

[tscheffel]

Two quick questions:
1) How best to ensure the horizontal stabilizer stays where I want it?
2) How best to ensure the wings stay locked together in flight?

I centered the stabilizer and applied the 4 small pieces of tape that came with the Radian but that doesn't give me a lot of confidence. I saw one YouTube video where a Radian owner showed how he applied one drop of glue to each side of the stabilizer/fuselage seam for added security. Do you guys concur with this?

Regarding the Radian wings, there is a rod that aligns them, and they fit snugly within the fuselage but I assume that snugness wears down over time. I have seen (via YouTube) some expert Radian owners launch their plane by holding one wing tip and slinging the plane upwards. I assume they've made a mod to help keep the wings locked together. Magnets? Tape?

[Fig]

We used some higher strength tape like Gorilla tape. A good packing tape would work as well and you can get it in clear.

[rcers]

The outward force on wings and tail feathers is negligible. When the surfaces are under load the friction of the tube is enough...

I have flown high dollar models with nothing to secure the wings.

The tape is more than enough.

Mike

[Rockin Robbins]

Originally Posted by tscheffel

Two quick questions:
1) How best to ensure the horizontal stabilizer stays where I want it?
2) How best to ensure the wings stay locked together in flight?

Resist the temptation to use rare earth magnets on the horizontal stab. They are too heavy way back there and bother your CG enough to cost you adding some weight up front. When you're ready to move the CG back you might revisit the subject.

Just bring along a roll of scotch tape and use four strips of that, top and bottom. It will be MORE than strong enough and weigh just about nothing. When I revisited magnets I decided the tape worked so well why bother? Actually I installed the magnets, then removed them again!

The wings stay just fine with no help. If you find that the interlock is getting sloppy you can just restore the shape of the foam by dipping the wing root in boiling water or pouring boiling water over the interlocking key on both wing surfaces. Do this carefully so as not to get too much swelling and it will be as good as new.

[tscheffel]

One last question before the weekend arrives: what is stabilizer decalage??

I see a picture of it labeled in the following Radian article but I'm not sure of its meaning: http://glidefast.typepad.com/glidefa...d-set-ups.html

[BrokenSpoke]

http://en.wikipedia.org/wiki/Decalage

[Rockin Robbins]

First of all, Paul Naton is the acknowledged expert on making the Radian fly better. And remember clearly what I said above: his better is your uncontrollable.

The Radian was designed the way it was purposefully, carefully and expertly, then refined in testing over months of preparation. Horizon Hobby is no Nitroplanes or Bananahobby. When a plane is the way it is, with a few notable exceptions, Horizon has well defendable reasons for that.

In the Radian's case the decalage, the difference in angles of attack for wing and horizontal stabilizer, is put there so you as a beginner can fly the plane. Do Paul's great mods and you will find yourself with an expert class competition sailplane. IT will be incredible and YOU will be very unhappy because that expert class sailplane will be a pile of peanuts in less than thirty seconds.

[tscheffel]

Unfortunately, no flying today since winds are 10-20 MPH. Really disappointed.

It's just as well though: I was tightening all the screws last night and the rudder thumbscrew broke. If I make it to tonight's indoor fly-in session I'll see if I can buy a couple from another RCer, otherwise I'll either make a Hobby Town trip (would they stock them?) or will order online.

I've read that there are better alternatives than the stock thumbscrews/mounts that come with Radian. Anyone have a good online source? Thanks.

[Rockin Robbins]

While it is possible to treat those thumbscrews real nice and get away with them, I think eventually just about everyone overtorques the things and breaks them. There are lots of alternatives but I'm away from my reference stuff and don't want to get it wrong there.

Now let me expand on my earlier post about Paul Naton's mods, because some of them CAN be done by a newbie and even the newbie will say "WOW!" when he's done. So let's go down his mods and see which are appropriate for a brand new pilot.

1. Changing the CG. NO!!!!!! Leave that alone until you have some experience under your belt. Changing something is meaningless unless you are thoroughly familiar with what you are changing FROM. How can you measure improvement if you don't know what you are improving FROM? Leave it alone for now.
2. Changing stab decalage. Nope! Again, part of the newbie friendliness of this plane comes from the decalage, which slows this plane down and introduces slow speed pitch stability. And you guessed it, How can you measure.......From?
3. Move attach point of rudder control horn and change clevis hardware to something a bit more dependable. DEFINITELY! Get that straight shot to the horn and switch hardware. Will make elevator control more exact without changing the flying characteristics at all. Also pay close attention to how he increased support of the outer push rod sheath to eliminate flex movement when there is load on the elevator. This will be WELL WORTHWHILE.
4. Switching to a different battery. While the stock battery is okay, you will get more thrust and save a lot of cash by switching to a 25C battery. I use the Hobby King Rhino 1300 pack and can agree totally that I get more power. I also saved $25 per battery pack. Don't toss the stock one but don't buy another either.
5. Tape over the hatch front. Why not? I doubt even he can note the improvement, but sometimes its about your attitude, not the measured increase in performance.
6. Prop change. Strictly optional. Unless you're in competition and need to get to 500' as quickly as possible for some reason, I'd pass. Why? The stock prop is good for five or six climbs to altitude. His prop exchanges climb speed for duration. Subtract two climbs, minimum. This one is just a judgment call.
7. Change holes for elevator pushrod. NO! This is to make his plane fly without overcontrolling with the CG and decalage mods. You don't need it yet.
8. Tape leading edge of flying surfaces and top and bottom of wing. Wet-sand wing to remove mold marks. Tape, YES! Sand, judgment call. Studies have shown that model wings benefit from turbulation resulting from irregularities. But this is like the Olympic swimmer shaving his legs. More about attitude toward attention to detail than any real improvement. He's in competition against multi-thousand dollar sailplanes. I'm not. I left it.
9. Pushrod supports get a big YES. Follow his instructions carefully for a big improvement in responsiveness.
10. Carbon tow on fuselage. Another huge YES. Fuselage flex is something we all deal with in a Radian. It isn't harmful to the plane but it makes our control what we enter, not how the plane flexes. You will notice the difference.
11. Plywood fin reinforcement. Yes if you feel up to the job. This is something that will eliminate the side to side flex of the vertical stab on rudder application, making rudder responsiveness better. It is more of an extensive job and shouldn't be done if you're unsure about your abilities in splitting the foam, inserting the plywood and gluing all back together. This will shift your CG and I recommend that you balance it out initially back to the factory specified 63mm.

In other words: stiffen the plane up and make it more dependable but don't compromise its beginner friendliness yet. When you are ready it's important to do the decalage, CG adjustment and nerfing the control throws all together. And I'd go very carefully back a couple of millimeters at a time with the CG adjustment, testing to ensure that you are still comfortable at each step. A plane that is beyond your ability to fly is called a rock, or unguided missile.

[tscheffel]

@Rockin: Thanks for commenting on Paul's suggested Radian mods. It's nice to get another experienced flyer's perspective.

Too late on #4: I bought a spare battery when I bought the plane. I'm sure I'll upgrade down the road when I become a competent pilot and want more power.

What is the purpose of #5 (taping over the hatch front)? I assume it is to reduce air turbulence but am not sure.

I did #8 using Scotch Tough transparent duct tape. I also taped along the top and bottom of the fuselage and the leading edge of the vertical tail.

I ordered replacement Dubro mini EZ connectors and 2 canopies. Hopefully they are here by the end of the week.

[Rockin Robbins]

@#$%^*#$%@, Martha, I killed it! Just when it was getting good....

While the thread rots, might as well post a video of a demented Australian(?) kid who thinks the Radian is a 3D design and decides to do some hovers....

YouTube Video

Dang! Wong video..... Okay, roll Australian(?) kid!

YouTube Video

And after he's done, who's to say he was wrong? Maybe the Radian IS a 3D plane!

[tscheffel]

I saw that Australian kid's video long ago and that convinced me to get a Radian. The stuff he is able to do with a sailplane is amazing! Impressive skills.