You will crash !!!
 

Wise words, which I heared countless times here on RCU ...

Anyway, [link=http://users.skynet.be/Logion/Brommer/MOV02920.rar]here[/link]'s the 17 second long video !!!(caus that's how long my first flight lasted)
It's hard to follow the plane once in the air, but if you look closely, you can see something white moving on the bottom of the video.



Why did it crash ?
Because the ailerons didn't work the way they had to. I had as good as NO CONTROL over the rolling of the plane. And the plane just started rolling to the right very fast when I took of and I wasn't able to roll it left again.

How will I solve this in the future ?
I will use iron or plastic hinges on the ailerons instead of those stock paper-thingies, which hold the ailerons now. (these are the cause, because the ailerons couldn't have enough throw with those hard-paper-hinges)

What's the shape of the plane now ?
still pretty good. Only the fuselage took damage. I was lucky, the person standing next to me on the video even showed me how to fix the plane, without having to buy a new fuse.


please go easy on me,
Prophex

RE: You will crash !!!
 

I assume that the "little paper thingies" you are referring to are CA hinges. There is no need to find something else, because thousands of flyer before you have used these hinges with no problems at all. It's not possible for them to "not have enough throw" as you indicated in your post. I would relook at your airplane and find out what caused the accident. If CA hinges are installed properly the work just fine.


Just my .02 worth

RE: You will crash !!!
 

OH, but look at all the fun you are having learning on your own! :eek:

RE: You will crash !!!
 

I'm not learning on my own

I just did my first flight on my own, without the instructor taking of. (my mistake)

RE: You will crash !!!
 

It is doubtful that the hinges were at fault but rather improper assembly and alignment of the plane. I do not know if you corrected the problems discussed in the previous thread but they were SEVERE and the plane should never have been flown in that condition. PRIOR to any further flights, please have an experienced pilot/instructor check out your plane. Otherwise you may be doomed to repeat this scenario. While we play with these planes they are not toys and must be given respect for the machines that they are. Be happy that nobody was hurt.
Sorry for your loss.

Bruce [:o]

RE: You will crash !!!
 

Before you glue the new hinges in, test fit EVERYTHING and get it to fit right. You may have to bend the torque rods to fit right. I don't know, I'm not there. As we have said before, get some LOCAL experienced help. Ask someone who actually flies not just the Hobby Shop owner unless he actually flies. A lot of them don't and are just guessing when they tell you stuff.

RE: You will crash !!!
 

Is it possible that the aileron direction of movement was wrong? With the plane on the ground ready to fly away from you, stand behind it. Move the aileron to the left on your transmitter. The left wing aileron must move up, and the right wing aileron must move down. In analyzing your problem please understand that the average model plane will fly fairly well with just one aileron. I may not turn as well in both directions, but it is manageable in the air.

RE: You will crash !!!
 

I guess the old saying applies a bad workman always blames his tools. :):D

RE: You will crash !!!
 

For CA hinges to stick properly, you need to be sure the slots are cleaned out and that the thin CA wicks properly into them. You need to be sure you leave enough space between the stab/wing and the control surface so that you get enough throw... if you push them up against each other too tight, you won't get much throw out of it. When I glued CA hinges into my Avistar ARF, I moved the control surfaces back and forth over a very large throw range while the CA set. This ensured that the CA hinge didn't get too stiff, and that there was enough spacing between the stab/wing and control surface to provide a good amount of throw. After you've let it set up an hour or so, it's good to give them all a good hard tug to be sure all of the CA hinges set properly in their slots, and work them up and down a little to be sure they are still loose and have good throws. You should also be sure that the hinge goes about an equal distance into both the stab/wing and control surface slots... sometimes the hinges want to go too far into one of the two slots, leaving only a small portion left to glue into the other slot, which will make for a weaker hinge. One trick I've seen in to put a pin through the center of the CA hinge, this provides some spacing between the two items being hinged, and centers the hinge between the two slots.

RE: You will crash !!!
 

Always hold the control surface at full deflection while you glue the hinges, or you will not get much throw. Then, as the CA cures, flex it repeatedly to keep it from stiffening up.

RE: You will crash !!!
 

Prophex-
We want you to understand that NONE of us wanted this to happen to you or we would not have taken the time to try and help. Assembly instructions must be fully understood and followed closely. If you have a problem with a step, resolve it before continuing to the next.

Good luck on your rebuild.

RE: You will crash !!!
 

Here is a great article on CA hinge installation from RCU:
http://www.rcuniverse.com/magazine/a...?article_id=55

It describes everything you mentioned.

RE: You will crash !!!
 

Prophex, I can't tell if anyone other than me took the time to download and decompress your film. It was very hard to see the plane once it left the ground, but from what I could see, here's what happened. You did not have control on the takeoff roll. The plane got up to speed and you pulled back on the elevator. This resulted in a very steep climb. Due to the steep climb, your plane had very little airspeed. When a plane has a low airspeed, guess what happens to the aileron control? Yes, they become less effective. From the film, it appears that the real problem is you were not ready to takeoff on your own yet. Reassemble the plane according to the manufacturer's instructions and have the instructor take off until you get more comfortable. When you do takeoff, you need to climb out at a more shallow angle so the plane has enough speed to allow the ailerons, and the wing, to do their job.

RE: You will crash !!!
 

So, basically what you said and he said in his initial post, it was a stall due to a slow, steep climb after take off?
Him saying it rolled right quickly is due to not enough air passing over the airfoil to create lift.

I'm a newbie, just making sure I correctly understand here.

RE: You will crash !!!
 

sounds like prime example of a tipstall.

RE: You will crash !!!
 

Shakes,
as a science teacher, I hate for people to be misled about lift. Although I wasn't a physics major in college, I did have 8 hours of physics--enough to know this. The lift provided by an aircraft wing has very little to do with Bernoulli, and his principles of fluid dynamics. Yes, air flowing over the top of the wing does create a temporary "low" pressure, but this pressure is no where near strong enough to lift even one of our models off of the ground, much less a 747 fully loaded with passengers. The main cause of lift can be explained by one of Newton's laws of physics--the same law that explains how rockets climb into space. Newton's third law states that for every action, there is an equal, and opposite reaction. As air hits the bottom of the wing, it creates a force on the wing. The wing will push back on the air with an equal, and opposite force. When the air's force is strong enough, the wing will push hard enough on the air hitting it to lift the aircraft off of the ground. The faster the wing is traveling, the harder the air will hit the bottom of it. If you hold your hand out of the window of a moving car, and keep it parallel with the ground, then nothing much happens. But, if you angle the "leading edge" of your hand up, then the air hits more of the bottom of your hand, and causes your hand to go up. This is because you have changed your angle of attack. that is what the elevator does. By lowering the tail, the aircraft exposes more of the bottom of it's wing to the airflow. This creates even more lift, and the aircraft climbs. Too steep of a climb causes a stall, but this is because the force of the air can no longer overcome the force of gravity, and the plane begins to slow down, until there is not enough airflow to create the lift required for flight.
This is why flat bottom airfoils are used for trainers--because they produce the maximum amount of lift for a given airspeed. Symmetrical airfoils are used basically for aerobatic purposes. Semisymmetrical airfoils are used as a compromise between the two.
Why is the top of the wing shaped like it is? Although there is a little bit of Bernoulli's principle being applied, the airfoil must be curved on top to reduce turbulence--it smoothes out the airflow over the top of the wing. This is also why propellers have an airfoil to them, so that the second blade isn't constantly running through turbulence caused by the first blade. It helps smoothe out the air flowing around/through them.
Sorry to ramble on and on about this, but I had to jump in here and give my two cents worth of physics lectures. I know some will disagree with me. I once had a physics professor say--how airplanes fly is still not completely understood. I don't know of I buy that or not, but that's what he said.

RE: You will crash !!!
 

I think the difference in his original post and in what I added is he decided the ailerons malfunctioned. From what I could see in the film, the plane just wasn't going fast enough. I'm suggesting that rather than fixing the ailerons, perhaps he just needed more airspeed.

RE: You will crash !!!
 

first and foremost, it always sucks to crash so i feel for you. but at the same time, there's a few things i'd like to say about this crash.

i think it is very unfortunate that you would blame the ailerons for the crash. i have used traditional and CA hinges and find that if anything, CA hings are just as good if installed correctly.

like piper chuck, i just looked at the video but unlike him, i don't think it's tip stall. it looks like you could've pulled it out. and it was flying at a good clip when it went in so i'm incline to think that it was either the plane really was just so poorly built it couldn't be righted even with full aileron OR pilot error.

one thing to note is that in the original post, it should turn much better LEFT than right because deflections of ailerons left were significantly more than right. anyway, before we get start to hypothesize about what happened, let me ask a few questions

1. what were the throws you were able to achieve after dremeling and loosening up the ailerons?
2. did you do a preflight check to see that all surfaces were working and working correctly?
3. why the hell didn't you get your instructor or at least an experienced pilot to maiden it for you. that plane is NOT a trainer. from the looks of it, it has no dihedral built into the not flattom-bottom wing. it is a high wing stunt plane.

screw it, i WILL hypothesize with the danger of looking and sounding like an idiot. i think you either forgot to hook up the ailerons OR you didnt' even to use them (ask smoggyboy what happens when you forget that ailerons are important) OR your low rates were so low that they weren't effective at all. there is NO way that you had THAT much left aileron deflection, as shown in your pictures from the other post, that you were unable to right the plane.

i am not convinced otherwise. that plane was going well above stall speed when it hit the mound and i didn't see it rolling left at all. if anything you might have been giving it some left rudder but no left aileron. left rudder won't help you much if your plane isn't trimmed for level flight.

i don't think that your ailerons were reversed because you would've plowed it in much earlier. CG was okay since i didn't see you rocking the wings too much and snapping after take off.

only other possibility is that you were shot down or the radio malfunctioned. do a range check. but honestly, it looks like you flew it all the way down to it's doom.

so what does this mean? next time you fly, have it checked out by an experienced pilot. it doesn't have to be an instructor. have the person maiden it for you and you can help him with trims if you need to. don't attempt to maiden it yourself unless you already can fly. by the way, you are too close to those houses.

on a more sympathetic note, the maiden of my trainer i did myself as well. i am self taught so i'm not against it. it was a $50 no-name arf that i put together. it was so poorly made, wings warped and not aligned that it did take almost full left aileron to right it. so i know that some arfs will build poorly. i am a better builder and buying better arfs so that has resolved some of the issues but not all. i still have a hair raising time maidening any plane i love (which incidentally is every one of them other than my electrics). don't be discouraged by it. luckily i was able to land without any incident and physically adjusted the ailerons. thus the neutral position of the ailerons were about 5mm left aileron. anyway, don't be discouraged... but understand what happened, that is the most important thing. i doubt the CA hinges had much to do with your unfortunate crash.

RE: You will crash !!!
 

2Slow...

Not trying to dissagree completly...but you arent giving the airfoil enough credit for the lift it provides....

This is why in high-speed GTR type race cars, the underside is created in a way that creates alot of extra turbulance...

More than once a car has lifted of a track into a 20-30 foot high backflip because of the lift created by the very aerodynamic, and yes, a couple of times the car was on level ground, not topping a hill...

Also, the flying-wing jets (B2, Nasa X-planes) rely completely on the life of the airfoil, as a matter of fact (watched a show on discovery wings today), the b2 actually flys with a tad bit of down attitude....as its found to increase the amound of lift because of the wing/fuse design...

Im not arguing, because a plane can fly without an airfoil...that has been proven as well, there are planes, especially in the rc world, that fly using the "Deflection" method, however, its a very inefficient way to provide flight...thats why most production aircraft use the airfoil....

I have no physics experience, im not pretending too...im actually just regergitation alot of what ive read (i like to read anything i can about science)

Both theories break down at the same point, and this is why people are so confused...

Inverted flight...in both theories, a plane should dive quickly in inverted flight....but they dont, with symmetrical or tradition airfoils, a plane can fly pretty well upside down...thats where the confusion comes from....

RE: You will crash !!!
 

That wasn't your mistake...it was his. He should have known better...and insisted on doing the maiden. Did you ask to do the first flight yourself, or did he suggest it? Either way it was a bad call, as the end result shows. Hopefully at least now you know what not to do next time.

Pre-flight check EVERYTHING on your plane each time you (or your instructor) fly it until you know the plane, and know that it is proven.

Jim C

RE: You will crash !!!
 

That's the first problem, I glued em on with epoxy and not with scond-glue (this is CA glue right ?)

Perhaps I ascended to fast, but I just had nearly no control over the rolling of the plane.
Let me explain why. Ass stated in one of my previous threads, I had problems with the throw of the ailerons. They just didn't give enough throw (comparing with 3D planes, my ailerons didn't even move) I said that this was because of a los due to the torque rods. Because when I first installed the ailerons, while building the ARF, the torque rods were completly not aligned. (there was a difference of at least 1 or 2 cm.) After an experienced pilot took a look at it, he told me that that was gonna be a big problem and that I had to bend the rods even again. Unfortunatly, the ailerons were already glued in place.
So he told me to just hold down the ailerons and then bend the torque rods with a wrench. BUT, this resulted in the wood inside the wing being crushed, because they couldn't hold the iron torque rods. I heared the wood being crushed and immediatly stopped, took the ailerons of (this wasn't easy) and held down the other end of the torque rods also with a wrench. Then I was able to bend the rods even again, but the wood was still a bit crushed because of my first attempt with the ailerons still on.

And that's why I had much less control over the ailerons when flying and thus that's why I crashed.

However, today I solved this problem once and for all. I putted some small pieces of paper inside the holes in the ailerons, in which the torque rods are connected. So now the holes are not that wide anymore and the torque rods are stuck really good.

before:

http://users.skynet.be/Logion/Brommer/DSC02925.JPG

after:

http://users.skynet.be/Logion/Brommer/DSC02926.JPG


MORE AIRSPEED ?! Damn, I already thought the plane was going way to fast. I thought the 46 AX engine was to much for this .40 trainer.

1. I didn't messure them, but they stayed pretty much the same. Now I get 7,5mm up on both ailerons, 5mm down on the left aileron and 3,5mm down on the right one. In my opinion, this isn't enough
2. Offcourse, I always check everithing first. Range check, checking all the controls, looking if everything is attached good, ... All was working fine (except little aileron throw)
3. It's a trainer and I wanted to do the first flight on my own ... (I already blame myself enough for this, so don't continue arguing about this [:-])

I asked it ...



BTW, this is what got destroyed:

the top of the fuselage was torn of:

http://users.skynet.be/Logion/Brommer/DSC02922.JPG


How couls I fix this ? Just buy some pieces of wood and replace a part of the top of the fuselafe and recover that part ?


thx for all the input,
Prophex

RE: You will crash !!!
 

The point I was making is your takeoff climb was VERY steep. When you did this, your air speed was low. This will result in little aileron control.

MORE AIRSPEED ?! Damn, I already thought the plane was going way to fast. I thought the 46 AX engine was to much for this .40 trainer.
[/quote]
Things do happen quickly in the air. More experience will help you develop the instincts to deal with these things.

RE: You will crash !!!
 

is it me or are the ailerons in the picture not deflected at all? if you were applying full left aileron and the wing ripped loose, the deflection should still be there. it looks like it is completely neutral. this would lead me to believe one of three things happened

1. you may have been shot down
2. the aileron servo failed
3. the connection to the aileron servo was faulty

chuck... i agree that the takeoff was way steep but... did you notice that the last few seconds of flight right before he dove into the pile of whatever it was, he was still not rolling left. at that point, it looks like it definitely has enough speed for the ailerons to be moving.

prophex - i don't know what "scond" glue is but if it say cyano... something on it, then it should be. also, it needs to be thin type. as for the throws, if built correctly a high wing trainer can fly on three channels, rudder, elevator and throttle so don't worry about it.

the damage is okay. just repair with plywood. i think you have enough of the seat remaining not to have to worry about incidence. just make it strong... trainers are great for repairs because they start out so light! good luck!

RE: You will crash !!!
 

When a plane is inverted, you must give down elevator, which (since the plane is inverted) pushes the tail down, exposing more airfoil to the air, creating more lift, thus the airplane climbs, or stays level.
Think about it like this, if airfoil created a substantial amount of lift, then how in the heck does a fully symmetrical wing fly? If wind flowing over a curved surface is capable of creating a very low pressure system, then you'd have a bonified problem--equal, low pressure above and below the wing. In this case, no net lift would be provided, and the plane would simply not get off the ground.
You're right, there is a point in which both theories fail to explain everything. I guess at that point you simply put 2-8 30,000 lb thrust turbine engines on a boeing, and it doesn't have a choice but to fly:D
Isn't it amazing that after over 100 years of flight, we still don't fully understand it all. This argument will likely go on well beyond our lifetimes.

Had to edit this post due to a brain fart :)

RE: You will crash !!!
 

Prophex, Sorry about your mishap.. Yes on maidens, if your a new
pilot, let an experienced pilot take it off and trim.. "After PFC'S..
Pre-Flight Checks" It'll save you more times than not... which
brings me to what else you said, " an experienced pilot took a look
at it, he told me that that was gonna be a big problem and that I had
to bend the rods even again" in reference to your the torque rods
were completly not aligned, Why not just adjust the rods??? Trim/
clean out the torque rod exit hole. If not enough screw adjustment,
cut and put another "Z" bend... CA hinges work well, (I did wear mine
out after over 100+ flights) but you do need to have the hinge stright
and equal on both sides, clean out the slots, to insure the CA gets to
all of the hinge/wood.. drilling a small hole in the center.. of the hinge
slot helps in doing this... Trainers do have very little movement on all
control surfaces when compared to any other plane...