rabfan

Like many new scale pilots I bought a 22E hoping it would allow me a cheap introduction to the hobby. Once it arrived I charged up the battery and got to work. I went slowly to try and get a feel for the machine and the controls. Things were going ok on ground runs although I felt the RTF setting seemed a bit wierd. Ground runs of course got boring and I wanted a taste of real airtime!
Well being a halicopter pilot I understand the mechanics and physics behind flying helicopters so I felt pretty confident that I'd pick it up quickly and figure out the handling qualities of this model. After all I am a commercial Helicopter pilot with almost 3000 hours of precision long line time so I figured "I can fly this thing right?" WRONG.....

Even though I took it easy I've since learned that this thing is nothing like a real helicopter as far as response time/quality and of course perspective. The major difference being that I'm used to sitting in the machine and work in an environment where if the helicopter takes off without you in it, things go wrong. Suffice to say things did go wrong.
I was able to slow the inevitable damage process by chopping the throttle whenever things got out of hand. Never the less reaction time has it's limits. With growing confidence I would attempt to bring the 22e into a 2 foot hover. It would begin a spin and drift ever insistently to the left whereupon I would cut the throttle and bring it back to my landing pad. Several blade strikes later and this was the result;


It's actually not as bad as it looks. I broke the tailboom off by trying to bend it back, and the blades are like that because I wanted to see how they were made. Basically only the boom and one blade grip have been damaged. well, and 2 sets of blades........

So I bought another 22e for backup and spare parts. I also bought someone's wreck that has multiple upgrades for later on. Later on being if I can ever actually fly this thing one day.
Under the suggestion of another board member I went to Radd's school of flight and read through the whole flight lesson including tuning and set up. I've decided to do it properly this time!
Here's the new unit!

It came with a Li-poly battery plus an extra 1300 MAh battery. The 1300 sure has more jam to it! I've read that it may be too much for the 22E's head speed. I tend to believe it as the machine sounds way different.
There also seems to be a good wobble in the main drive gear. Hopefully it's just mounted a little crooked and not a bend main shaft.
I've set up the head and messed with the tail limit and gain. I think I've just about got it.
As you can see, I've added a significant amount of weight to the front. It's almost balanced now. I'm going to try adjusting the head forward to see if I can level it for hover.
My training ground;"STAY IN THE BOX SOLDIER!"

3 batteries later and I'm still trying to set the machine up properly.


More to come!

rabfan

Staying in the box................


Upgrading the box................

Atzanik

Great stuff! RADDS is the way to go for sure. I started out on the 22E and it served me really well. One bit of advice on what you've written. "Chopping" the throttle when you are in trouble and not on the ground can be bad. If you are flying around and you lose orientation and you're going to go into the ground at an odd angle, go ahead and chop the throttle. However if you are pretty level and you chop the throttle a few inches or a foot or two off the ground, when the heli hits the ground quickly, the blades will continue to flex and you'll end up with a boom strike. I was doing the exact same thing and wondered why I had so many boom strikes.

Instead of chopping the throttle, just back off it a bit and try to set the heli down gently.. either that or give it a bit more and go up and try to recover... this option requires more man stones if you know what I mean. It's the sudden hard land that's killing you.

As a heli pilot I'm sure you know all about ground effect. These poor little micros don't handle it all that well and go all crazy until you are about 2 - 3 feet off the ground. If you can get out to that height things really calm down.

Anyway, don't get too frustrated, remember this is all fun, and it's not a race... take your time and learn properly and you'll be pleased with the results.

rabfan

Thanks Brian!
I actually haven't been sucessful at getting the heli above about 1 foot as of yet. All of my damage has been a result of blade strikes with the ground causing massive blade sail and thus my boom strikes But I will remember the proper technique when I start getting higher. I'm glad to hear that the machine gets calmer at altitude cause it's pretty squirrely now.
One thing I have noticed is that the machine is way more stable with that weight on the nose than without. Without it, the machine walks left and countering with cyclic causes the onset of a dynamic roll. It has made the walking around on the ground technique rather difficult. I need a smoother surface!

Any more input is greatly appreciated, again thank you,
RJ

chopperdown

I doubt it is blade sail that causing you to have boom strikes. For one it is not an articulated rotor head like the 206. How tight or loose are your blade grips? The main reason for boom strikes is the blade sweeps aft (along way aft) allowing it to hit the boom. I didn't follow radds so not sure what he tells you to do, but shouldn't you have your training gear on. It will save on crashes and the heli will move around the ground a lot easier.

jtspin

RJ, welcome to the madness!

I started about where you did. While having nowhere near 3000 hrs, I thought, "I can fly the real thing, how tough can this little thing be?". I think it was more of a hindrance than a help. Trying to learn to fly at 4500' at the beginning of summer didn't help. My 22E wouldn't get off the ground in the stock configuration.

If I had one suggestion to make, I'd say to get rid of the nose weight. You can get it to balance a little better by sliding the tail boom into the frame as far as it will go (without cutting through the wires). I use a little forward tilt on the swash plate to compensate for the tail heaviness and a little right tilt to compensate for the left translating tendency. After you get it all tweaked up, it will hover hands off for several seconds.

It may seem more stable with the added weight because your required head speed may be higher with the extra weight. Remember, unlike your full scale heli, the throttle stick increases both head speed and collective pitch. With the stock Tx, I don't think it's possible to run a constant head speed and use just collective for lift (even in 3D mode). You might want to experiment with the knobs (set switch 8 on the back of the Tx to unlocked) and see how they affect collective pitch (and to some extent, head speed).

I think Radd tells you not to use training gear, but it will help the heli to slide on almost any surface and you won't have to worry about dynamic rollover. It also cushions hard landings a little bit.

Good luck!
-JT

rabfan

fixed it for ya :P
The 22E does in fact have an articulated rotor system due to the lead and lag possibilities and a small amount of teeter. The brass screw even though fully tightened still allows a small amount of teeter, on mine anyway.

More flying today......er ground flying....er well I tried to hover and hit a fence which resulted in broken parts which I stole from the first heli. More ground flying followed by an attempted hover followed by a panic and instead I tried to cushion and overcompensated and then hit the garage......more parts stolen from the first heli.
Thank God for spare parts!

edit: I think my yard is too small.......I may have to go to the park

JasonJ1969

Hey Rab, I stopped chopping the throttle on my 22e a long time ago. Now, if things are looking bad, I fly it until parts are flying. I have found that trying to stay in control until the bitter end has reduced my crashing. Now, if in doubt, I give a bit of collective and get the thing into some semblance of a hover, then land it as best as possible. I have been through a few blades and head bits, and have bent the boom back a few times, but otherwise all is good. I find myself taking more chances with this one than my Falcon. One thing I just did was, after burning out two tail motors, is getting a ducted fan and installing it. Holds well, bigger direct drive motor, and no way to have a tail rotor strike. Very worthwhile in my opinion.

I would kill to have the loot to learn real helicopter flight...Couldn't do it in the military, bad vision...[&o]

rabfan

Thanks for all the comments guys.
I have removed the weight from the nose as suggested. I had already tilted the head forward and right slightly to compensate for the drift. I did add a small bit of weight to the canopy nose as well.
Some weird stuff going on though. It's like the machine feels different from day to day. Might be my learning curve I guess. I have noticed that at the lift point the machine will sit on the ground until I apply a little cyclic(right or forward) and then suddenly it will lift off the ground like something in the head is binding. I have lubbed the sliding components but this issue still remains. Not really a big deal because I know it's coming but still...
I also upgraded one of my canopys.


So I'm still flying on the ground. I've moved to a smoother surface however and the machine can slide around a little better.

rabfan

I checked out those ducted fans. They look pretty cool! All you need is an EC130 body and it'd be all set.
I actually ordered a Feigaeo brusless 120 shorty motor and ESC so hopefully that will be here soon. All the upgrade parts will go on the scale model machine once I learn to fly.

I got a massive loan for my flight training and then put it in with my new mortgage. It was the only way I could do it.
It's one of the toughest industries in North America to get into because of the huge gap in between new 100 hour pilots and the experience level needed to actually accomplish real world commercial flying.
Probably something like 3 in 10 are successful and make it into a real career.

rabfan

Today was AWESOME!
I know you guys suggest getting the machine into the 2 foot hover arena but I always seem to have horrible crashes cause I'm still learning control and reaction.
I've been flying the machine on the ground at the threshold of lift off and today I gave it that extra click on the collective. I was able to fly it about 4 inches above the ground and unsteadily hover the 22e around my new flight arena(hot tub cover). I wouldn't say that I was in control but I'm geting the hang of it! No busticated parts today!
RJ

chopperdown

I know what you mean about getting a flying job.I is all over the world I'm sorry not just in north America. In new Zealand most people (that make it) finish there training and get an instructor's job earnng next to nothing, living with mom or being kept for by there wife and building hours. Then after many many many dollars spent and boring hours flown can we get jobs and start to enjoy life. To be successful you have to REALLY want it and love what you are doing.

Anyway reason for your lifting problem: The 22e doesn't like high head speeds at all. Some people get there birds to lift at 50% throttle, I'm not sure how they do that cause even with a stock setup mine would lift best at 40% maybe 45%, if i was to let it lift at 50% then she would jump high if i didn't add cyclic input at the right time. Bear in mind that this symptom could also be a result of a little wind. If it still a problem try to adjust your right knob on your controller anticlockwise, be sure to unlock the #8 dip switch first.

rabfan

Hmmm, mine lifts off about 1 click past 50%. I wonder if I should increase my zero pitch slightly? I haven't measured the actual pitch, just by eye. The blade tracking is spot on after some small adjustments.
I'll try the PIT adjusment for now....
What do you think?

chopperdown

I would adjust your pit 1 or 2 clicks anticlockwise and see what happens.

roychye

Hi,
22E was designed for the ease of manufacturing and low manufacturing cost (inspect according to what i learn in engineering course ), poorly casted plastic rotor set and design allow gaps within the links. Apparently the gaps lead to an unprecise design. Dealing with some crashes, i found out something that could be done to compensate the poor design, hope it does work for you guys as well.

First of all, piece of shim is added to the t shape holder (shown in photo), the gap within the PartA and Part B makes hovering like a hell (free movement of these parts allow the blade sweeping plane moves freely, as a pilot you should know how terrible this could be!!!). To compensate it, a small piece of A4 paper is put in between the parts to minimize the free movement. I learnt this from a heli freak whom i knew from youtube.com.

Secondly, i found out that the flybar holder was deformed after a period of time. That might caused due to plasticity creeping, load ( high angular speed could lead to an obvious load though the flybar is light) or the allen screws are over tightened. Deformed flybar holder could not hold the flybar tightly and gaps allow free movement in horizontal plane. This could lead to a serious vibration at low and middle throttle and is bad for the mechanism. As what i've been taught as an engineer, thing should be solved as cheap as and as easy as possible, rather than spending money to get brand new part. What i've done is to simply add 1 washer between the gap, the flybar vibration was reduced dramatically by this.

Regards to the lifting in a sudden, i faced this problem before. It's mainly due to the free movement of blade grips in vertical direction, you can feel that by moving the blade grip up and down. What actually happens is I guess the deformed bearings and washer should account for the free movement. as shown in diagram, i found out that this is the most possible reason that causes sudden lift. No specified way to fix this , i fixed it by trial and error. You should find 1 washer that can hold the blade grip tightly, but not that tight until the grips cannot move at all. The washer i mentioned is the one used to hold the grips to T shape holder. Once you find that the free movement of grips goin up and down is minimized, you will feel the difference.

Well i know all these and fixed all these problems and supposed to fly my heli at the moment, unfortunately my motor burnt out.........


Regards
Roy

chopperdown

I also added this shim to the tee block. Made a lot of difference. This rotor head is not supposed to teeter lol. As far as movment in the blade grip goes, mine has non. It did have and then i replaced the grip with new, mixed and matched with bearings and stuff to find a good set up.

roychye

lol, seems like we 22e owners have been working hard on setting up this bird. In fact the flybar holder and blade grips problems of mine were solved by using the cheap metal upgrade, the cnc parts is able to hold the flybar and blade firmly. Vibration was just so little that it could be considered non. However, the ball studs of swashplate do not fit and have poor geometry issue so i sent it back to the seller and got full refund.

I'm studying in Australia, looking forward to a chance visiting NZ!!!

roychye

here is the attachment of the cnc part i mentioned.

chopperdown

so the boys in oz worried about the rugby? tough game. I looked at that upgrade, but i have decided to leave the 22e and upgrade to a T-rex. It has served me good tho

roychye

yeah oz boys crazy for rugby, not for me because i think it might kill me... i will also go for trex at the end of the day!!! wishing that day is not far from now.

rabfan

That Tbar does allow quite a bit of teeter on my head as Chopperdown and I discussed before. I will try shimming mine to stiffen it up.

In forward flight, the advancing blade is seeing the airspeed plus the head speed while the retreating blade is seeing the head speed minus the forward speed. This creates a phenomenon called dissymetry of lift. On full scale helicopters such as the Bell 206 and R22/44 teetering head is meant to allow the advancing blade to rise thus decreasing the angle of attack while the retreating blade descends thus increasing the angle of attack. This prevents retreating blade tip stalll which would otherwise cause a rolling moment towards the retreating blade side....in full scale helis anyway. I'm discovering that the modelling world does not seem to work on the same rules lol.

rabfan

HEAD SPEED! Holy cow! I made some adjustments last night and increased the static collective pitch. The heli lifted off just before %50 and wow! way more contrllable. I was flying! hovering around about 8 inches off the ground. I then tried to get a little higher and lost it. minor blade damage but otherwise a fantastic flight!
Excellent......it's all falling into place.....

roychye

I am not sure what you mean by the advancing blade and retreating blade, but i am quite interested in this sort of thing (that's why i choose to be an engineer)!!! I also feel that model chopper works differently from full scaled chopper. I know that full scaled chopper moves because of the different angle of attacks at different position of sweeping plane, in forward flight the angles of attack of rear half sweeping plane are greater than the front half. Greater anlge of attacks means greater lift so the chopper is able to move forward. Learn this from book, if i am wrong please let me know

by inspecting the 22E, i don't think it works in the same way. the chopper moves forward by tilting the whole sweeping plane.

regards
roy

rabfan

you got it right. Now take into account that when the helicopter moves forward each blade is seeing the helicopter's speed through the wind plus the airspeed on each blade caused by the rotation of the head. Looking forward from the cockpit of the 22e the advancing blade would be the left blade and the retreating blade would be the right blade. The left blade will see the airspeed of the helicopter plus the rotational speed of the rotorhead. The right blade will see the rotational speed of the rotor head MINUS the forward airspeed of the helicopter.
We know that the faster the air passes over an aerofoil the more lift it will create(just like an airplane). Therefore the left blade will be generating more lift than the right blade in forward flight(clockwise rotor system like the 22e). So if the left blade wants to make more lift it will want to go higher. Relatively, the right blade will not generate as much lift and a rolling moment will be created causing the helicopter to pitch right. On full scale helicopters to compensate for this dyssimetry of lift a flapping hinge is incorporated into the head design. On the Bell 206 the whole head can teeter so that when one blade goes up the opposite blade goes down. If the advancing aerofoil flying through the air suddenly goes up without changing the angle of attack through the controls(we're still talking relative wind speed) then the angle of attack is decreased as the air begins to hit the blade more from the top. Conversely, the retreating blade will see the air hitting it more from the bottom as it moves down, thus increasing its angle of attack and levelling out the lift on both sides of the disk.
At some point however the flapping is not sufficient to overcome this rolling moment and you get what is known as retreating blade tip stall. That is one of the reasons why there are VNE's on helicopters.

Let me know if you need a diagram.

roychye

Thanks for your explanation, i've got the picture of what you said. I'm a mechanical engineering student and took 1 subject named Aeronautical engineering last semester, i lost mark at the questions talking about helicopters (dealing with ground effect calculations, if i'm not mistaken), if i knew you before that i might get higher mark!!!

that subject just gave us a rough idea how does a helicopter work, i don't think my professor taught us something about the advancing blade and retreating blade (thanks i knew it from you) and that causes rolling in forward flight. Or maybe i missed out the lecture (this makes more sense lol). I just wonder if there is a autocontrol device to counter this rolling motion, like the gyro that holds the tail still. If there is no such thing it's gonna be my project one day!!!


best wishes
roy