beachbrada

My Feedback: (17)

So I just got back from my nail-biting maiden flight of my Twist .40. Here's the whole story, the wind was about 7-10 mph with times where it would drop below 5mph. When I checked my C.G. yesterday it was at about 5 inches back(manual calls for 4-5 inches) without the prop or spinner installed. So I figured once I installed these two things it should bring it forward a hair. Another thing was that in my excitement I totally forgot to install the canopy(not sure if it had any real effect). When I took off I instantly noticed something was wrong, the only way I can describe it was that the plane did not feel like it was on rails and more like it was dangling from a puppet masters strings. It felt so wobbly and there was alot of wing rocking. The first thing I thought was that the wind was pushing it around but then I really thought about it and the wind had died down. The next thing that came to mind was that it was too tail heavy. I have never flown a plane that was too tail heavy, only nose heavy. Needless to say I was very careful in my stick inputs and slowly descended for a immediate landing. Here's another thing, the plane didn't want to drop altitude. Even with it at idle speed it kept nosing up and I actually had to use down elevator to descend, I'm not sure if this is another tell tale sign that it was too tail heavy. Well I was fortunate to land it fine at what almost seemed like a harrier landing, it came in so slow with the nose slightly up(the thick airfoil is probably partially to blame). Well from what I have described does it sound like I was to tail heavy. If you're wondering I balanced it with my fingers along with my wife, which she held the opposite side, its not the most accurate method but all I can do for now. If it is too tail heavy I have space to move the battery forward. Just curious as to where you guys placed your battery to balance. For a little more info I have a 46AX up front and standard servo's all around. Just figured I'd tell my story and hear what you guys had to say about it.

ChuckW

It definitely does sound like it could be a little tail heavy. That big thick wing is pretty forgiving when it comes to CG though. You might try moving the battery forward just to see.

Also keep in mind that it is called a Twist for good reason. The thing is VERY maneuverable and it can do stuff very fast. Use low control throws at first and maybe even a little exponential in your radio until you get used to it.

It will tend to float on landing since it is light and has a big fat wing.

beachbrada

My Feedback: (17)

The low rates are set per manual and I used hardly any stick movements. It just seemed way to jittery in the way it was moving even at times when I wasn't putting any stick inputs. I will try swapping receiver and battery to see where the C.G. is at. How was your twist as far as the battery location?

ChuckW

If I remember correctly, I had the battery just behind the tank, where you have your receiver. I flew it with both a .46-AX and FL-70 4-stroke but I can't remember if the balance changed much between the two. I do seem to recall a half ounce of lead on the tail at one point.

brett65

My Feedback: (18)

A guy at my field flies one and he has the cg back to make it do better 3d flying. That is how you get hovers and good snaps and flat spins. If it was too far back then it would have not flown level. His does harrier type landings if he wants it to. I put the cg of my extra further back than the manual calls for so that it is more capable of crazy tricks.

TimC

It sounds like it is flying normal for the CG at 5". I think ChuckW's suggestion of expo is dead on. The Twist normally is pretty twitchy and takes some getting used to if this is your first plane like this.

JohnW

My Feedback: (6)

"in my excitement I totally forgot to install the canopy" - That will totally jack with many planes. I can't say on the Twist, don't have one, but it makes a huge difference on other plane's I've flown. No canopy = lots of drag above the center of mass of the plane, this will cause it to pitch up. Hence the down elevator you needed to decend. I wouldn't make any major CG changes (assuming you are still in the manual's indicated aceptable range) until you fly with the canopy.

beachbrada

My Feedback: (17)

I will install the canopy and add some expo to my low rates. I had only initially added expo to the high rates. And I will also double check the C.G. to make sure for a fact its within the 4-5 inch range. Hopefully the wind dies down more today.

Mr67Stang

Check the CG of this aircraft inverted and, as with all, zero fuel. Also do it by your self. Finger tips are okay... They've worked well enough for me to fly 1/4 scale and some larger. Use a sharpie to mark your desired C/G range (small dots work fine) but mark it on the top of the wing near the fuselage. Put your fingers in that range near the fuse (not out by the wing tips) and have your wife ready to catch it if it falls back but not doing anything to support the plane otherwise. Also do this indoors with no fans (wind) that may effect your ballancing act. When satisfied rubbing alcohol will remove the sharpie markings

chris6414

My Feedback: (10)

I have a Twist with a St .40 and 11X4 prop. Mine was also tail heavy when set-up per manual. I put a 2 OZ heavy prop hub and about 3 Oz of lead under the motor on the firewall. Now she tracks straight and is more predictable in all maneuvers. I also added a 6V receiver pack and she rolls like a drill bit now![X(]

beachbrada

My Feedback: (17)

You probably had to add more weight due to the fact that you had a smaller engine. Do you know how much that engine weighs? Hopefully if it is tail heavy I can swap the battery and servo and it solves the problem.

RCVFR

My Feedback: (7)

I suggest 50% expo on elevator and ailerons. You might come back down to 30% after you get more comfortable with it. Those big control surfaces with "0" expo are a guaranteed handful and a half. Congratulations on getting it back down in one piece!

TedMo

Beachbrada: Definitly sounds tail heavey plus the absence of canapy made huge difference. I would surely switch bat rx locations and check CG then. Aircraft are usually manageable when nose heavy but are bears when overly tail heavy. It's true that a degree of tailheaviness often is desireable for 3D but not all planes can tolerate it. 5 inches from ld. edg. for CG seems a lot unless wing has a 15inch chord. General rule of thumb for CG is 30% of chord. Of course this is variable to large degree depending on plane but since I'm not familiar with the Twist I have no idea what might be excessive. The thick airfoil no doubt saved you since had it been average thickness it probably would have stalled and snapped in. Good luck next time.

beachbrada

My Feedback: (17)

Well I just got the canopy installed with some double sided tape. I double checked the C.G. and if I have my fingers on the 5" mark it tips forward, if I move it forward a hair it just about stays level if I stay perfectly still. So I would say its about 4 3/4 inch back. I also added 60% expo to the low rates and 85% for high per the RCU review settings. Off to the field for flight #2. Fingers crossed.

beachbrada

My Feedback: (17)

Flight #2 goes as follows, with all the maiden jitters out or at least most of them I was able to concentrate more on flight characteristics. I want to say that the canopy helped out alot but I still had some wing rock. Is it safe to say that the Twist doesn't like wind, from the ground it didn't feel too bad, there would be a gust of about 8 mph every now and then. The trees didn't seem to be moving to much, but I could tell the difference when the wind came. When flying into the wind the plane seems to float even more. And I tried some knife egdes on high rates and boy was there alot of coupling. While doing a knife edge with the canopy facing me the plane would just roll towards me and be inverted in a matter of no time. So how do I go about this, I have a DX7 transmitter so would I just mix it out by applying some opposite aileron to keep it from rolling over? Also with the wing rocking I think it has part to do with some play in the aileron servo arms, I enlarged the holes a little too much and there is a slight play which may be allowing the ailerons to move. But overall the plane seems like its going to be a blast to fly once I iron out the problems. Its cool being able to do 10 consecutive rolls and only losing a small amount of altitude.

ChuckW

It's definitely not impossible to fly in the wind but it is very light and has a big fat wing so wind will tend to affect it more than other planes. Think of it as a challenge.

This is a pretty common characteristic. I crashed my first Twist doing a knife edge too close to the ground. I got my aileron input confused and you can guess what happened. You can try playing with the CG and other factors and see if that helps. You might want to try to learn to mix it out with stick inputs first after checking the other factors. That's a skill worth mastering. Using mixes in the radio will work also and that's probably what I would do one I did everything else I could to help the problem.

RCVFR

My Feedback: (7)

When you get comfortable with the Twist, it will be your "go to" plane for the wind. It is a joy to fly the wind with this plane. As to knife edge, it takes some touch to get it right. First, go lightly with the rudder. Too much rudder gives strange behavior. Just looking at the amount of rudder area gives a clue that there is a lot of force going on. Try knife edge and see how little rudder you can input to keep it on track. Then do the same with maximum rudder. Compare!

beachbrada

My Feedback: (17)

That was probably my problem, I was giving it max rudder throw. Because I'm so used to trying to force a miracle knife edge out of the Four Star(lets just call it a descending knife edge) Needless to say I just need to take care of the play in the ailerons and double check the other surfaces for play, and hope for a calm day so I can actually see if the plane needs any more trim since the wind kept me on the controls the whole time. Then I can log in some flying time and see what else I can do with the Twist. Jim, the wind seemed to toss my plane around, is this the same for you?

So Chuck, do you still have a flight ready Twist? If so what maneuvers have you been able to do with it(besides the basics)?

TimC

beachbrada, I lost my first Twist while trying to make a dead stick landing in a strong wind. For some reason (I'm and idiot) I tried to make it back to the runway when I had a big mowed field I could have set it down in. On the last turn I banked too steep and presented the Twist's box kite shape to a strong side wind. The wind took it quick as a wink into a tree I thought I had easily cleared.

ChuckW

No, I no longer have one. It's been at least 3 years since I got my first one and I crashed it doing knife-edges on the deck. I immediately got a second and flew it for about a year. With too many other planes laying around, the Twist wasn't getting much air time after that. I robbed the engine and receiver for another project and it just sat. A guy saw it in my garage and offered to buy it so I let it go.

beachbrada

My Feedback: (17)

If my Twist likes to float this one must want to enter orbit.

chris6414

My Feedback: (10)

beach,
You need to get rid of that servo play in those barndoor airlerons. Also make sure they are centered well. I use a flat laser level from leading edge to trailing airleron edge and it works good. Any good straight edge will do it. My ST .40 is pretty light as most of these I have seen have .70 4 strokers on them. My little .40 will take off right into the vertical on takeoff. She won't stay that way for more than 150FT until she hangs on the prop but an 11X3 may help that some. I had a 10X6 but it just didn't provide the vert performance I was looking for. I just use my Twist for a sport flyer and it does that well. I too found a knife edge difficult if I was applying too much rudder and power. I need to to try it at less throttle and rudder and see what I get. I love flying mine in the wind. I can just hang it or tear through it if I choose. The approaches can be a bit hairy though due to the Twists size and light weight. I am right on the throttle stick ready to hit it if she gets too weird on landing. It is currently my only fixed wing flier right now. I fly a Hawk Sport and also have a Jato Truck that shares what little time I have.

beachbrada

My Feedback: (17)

I just got back from the field and I got two more flights in. I took out the play from the ailerons and couldn't really tell any difference but I'm sure it will help in the long run. I was having a blast just floating in on the landings then turning around and pulling vertical on take-offs after about 40 ft or so. Im not sure but I think the expo is hurting the knife edge, I have 85% expo on my high rates and I think its delaying my inputs so I add more input to counteract this which ends up being too much input. I noticed this delay when I took off with high rates and while I was steering on the ground the Twist was zig zagging which I think was due to the delay. So my questions is, how much expo do you use, if any, after you maiden a plane?

TimC

I use 40% on all surfaces.