Raptor 50 SE Problems! "Flutter, Flutter" and a broken tank

[pipercub123]

Hey guys,

I went out with my 50 SE two weeks ago and had a flutter when flying. This is my second season with it and have only gotten a flutter once in a while with it. Mostly coming out of a flip or a loop. This time it fluttered pretty bad compared to the usual so I landed and inspected it. It seemed fine than while in a low hover I lost the collective and when I landed my tank popped out of it. It didn't seem like too hard of a landing. I found out my JR servo arm off from my JR [FONT='Verdana','sans-serif']DS821 Sport Hi-Torque Digital Servo broke. So I had plans of upgrading to all aluminum arms, but figured to throw on another plastic arm for now. After all, I flew it all last summer and fall and some of this summer with no problems. I took it out, did a hover to check it, circled around, pulled a loop and had a real bad flutter where the head speed didn't want to pick back up and than flutterd and came back. Than my tank popped out of it and the line came off so I autorotated back in. Hmm, my head speed seems to be fine. A little on the high side and my pitch is 0 at half stick and about +12 and -12 or about as much as I can get out of it. When I look at the built in gauge on the heli, the pitch needle lines right up to the marks. Perhaps plastic arm isn't up to the task and maybe my DS821 has had enough? I also have the DS 821 on the ailerons and the elevator. I'm about ready to order some new servos for her because if I don't I suspect a crash is coming and that could be just as costly. What would be some good servos that are budget friendly and would last a long time? I fly moderate 3D, but want to push it harder so I need good ones.[/font]
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[FONT='Verdana','sans-serif']Also, my fuel tank has holes in it where the two front bubbles are on the tank sides. The tank must have been rubbing in the frame. Anyone have this problem before? What's a good fix? Should I use some double sided tape on the dimples of my new tank to keep the vibration down?[/font]
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[FONT='Verdana','sans-serif']I've seen some guys fly some hardcore stuff with the Raptor 50 with my OS hyper 50 I don't think a simple loop would bog it down because my head speed is not low. Also, when the flutter stops the head speed seems to be right there. It's not like the flutter starts and the engine bogs down and than slowly spools back up. I'm also using 30% nitro and I'm flying G4 carbon blades. [/font]
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[FONT='Verdana','sans-serif']Thanks for the help![/font]

[Flyinfool]

Flutter is not likely to be a servo problem in a heli.
Blade flutter is usually a mechanical problem.
I would start by checking the dampers and the blade grip bearings.
Worn dampers and/or grip bearings are the most common cause of blade flutter.

Flutter puts a lot of stress on parts and could have damaged any or all linkages from the grips to the servo, check them all carefully.

Once you get a flutter, check your spindle to be sure it is still straight, I used to bend a spindle every time I had a blade flutter on my R50.

As for the tank, If the tank has a leak, get a new one, I never had any luck trying to patch one. Check your frames where the tank dimples seat, and use some fine sandpaper or Exacto knife to get rid of the molded in sharp edges that will cut the tank.

[BarracudaHockey]

Get rid of those servos, JR/Spektrum specifically warns against using DS821 servos in a 50 size nitro heli.

http://www.raptortechnique.com has a whole page on troubleshooting blade woof

[turbotom123]

A friend of mine had that same problem with his raptor 50 titan. He tried changing parts one at a time and the last part changed was the blade grips. If you are using the plastic grips they wear quickly with 3d throw. I am currently flying a raptor 50 also and i am using futaba 9252 on aileron and elevator, jr 8611a on collective and 9254 on the throttle and rudder and a gy401. Hope that this info will help you out.

[pipercub123]

Lots of good suggestions guys, of course I didn't expect anything else. I went over the heli a few minutes ago and grabbed a hold of the blade grips. If I try to move the grips up and down, they move about an 1/8" or so and the end of the blades look like they're moving about an inch. Wow. So I'm thinking those blade grips should be changed. I happen to have a set of new grips that I ordered thinking I'd need them for if I crash it, I didn't think I'd be needing them for general maintenance. I will check the spindle, hopefully that's okay. I would like to replace the dampeners, but will have to order those.

My question is how do I check the dampeners? Besides the obvious signs of deteriated or deformed rubber, what do I look for? Will bad dampeners develp cracks or just feel sloppy on the spindle?

I used to have a Venture 50 that had some slop in the grips and that was with new parts, but that flew fine. So I'm guessing that sometimes a little is okay.

Also, when I try to change the blade pitch by hand, there is slight play in the swash plate and it leads down to the servos having play. How tight should the swashplate and the washout arms be. Most helis that I've had always had some play, very minimal. The only thing that really jumps out at me is the grips, so I hope that's it.

I've also been doing some reading and what's the deal with the fix that involves flipping the blade grips? I think I did that with my venture 50 before I bought new grips.

As far as the DS821s, I was in college at the time I bought them and I loved the price of them. They've been good and have taken a beating. The collective servo seems to wiggle at the shaft a bit so I've ordered a replacement servo, a hitec 5625MG. I'm hoping the MG on the collective will hold up longer and with just over 50% more torque than the DS 821 I should have an okay budget friendly digital servo. It is definitely a step up from the DS821 and I wish I would have gone that route from the start.

My two cyclic servos seem to be fine so I'm thinking of leaving them. The collective takes the biggest toll on servos, right? I may eventually put in some 5625MGs.

I checked the HH site and they list the DS821 for up to 1.20 planes, 30 size helis, and 50 size electric. Are electric helis really easier on the servos than a nitro? Electric motors can put out some serious power.

Other than my few ?'s, I should be good to go once I get the parts in. I'll try to remember to get an update posted. (once I get the bugs out, I'll be having too much fun and could get side tracked) I appreciate the help. I've never had this woofing issue so it's been an experience for sure. Most of my past helis, I've sold right before they developed any serious problems. Man I knew I should have gone for that Raptor 90! My woofing is so bad in the air that when it does it the head speeds drops so low that the only way for me to maintain my altitude is to add more collective. Than the blades will eventually speed up if I'm not forced into a landing.

Anyone have these issues with other helis! This is my first Raptor and I'm wondering if I should go with the new Vibe 50 instead? Hmmm.

[BarracudaHockey]

The output shafts shear off and the amplifers die from vibration. There's a warning specifically not to use them on anything larger than 30 size nitro. I'm not trying to spend your money, I'm trying to save your helicopter. A crash is going to cost you more than 3 decent servos will.

As for the grips, the bearings get play in the grips and it causes blade woof, so does slop anywhere in the collective system. As for the dampeners, replace them if you're the least bit unsure, they cost what, 3 dollars for the reds? Lube them where the spindle goes through with silicon dielectric grease.

[cjcyclesrc]

One of my friends lost a Titan to a DS821 on the Aileron. I would not recommend using them on any of the controls. Barracuda is right about the dampeners replace them if you are in doubt and be SURE to lube them good with Dielectric Grease. Be sure to check the grip bearings. A notchy bearing can cause a woof. Be sure to put the thrust bearings in the right order when you reassemble it. I grease my thrust bearings with dielectric grease. If all that doesn't fix the problem try another set of blades to see if it fixes the problem. I saw a set of Thunder Tiger Carbon blades that were bad about woofing. After Hours of trying to fix it he borrowed a set of V-blades and the problem went away. Are you running stock mixing arms? The most I have been able to get out of stock mixing arms is about 22.5 deg. range. I have my Raptor 50 set up with OS hyper 50, MP 2, 8.7 gears, Radix Blades, Kasama Head, Throttle Jockey, HS-6975, 9252's, 401 w/9254. I run it at 1950 rpms, +/- 12.5 deg and don't have any problems with it bogging.

Check out my friends website it has a helpful site with lots of tips for Raptor 50's. Raptor Technique

[Flyinfool]

The stock raptor plastic grips do have a little built in play due to the draft angle in the bearing bore.
Some people use very thin shim stock around the bearing, some put a coat of CA or epoxy in the bearing bore and let it dry BEFORE putting in the bearing. That is the one place that the metal grips have an advantage over plastic.
It is hard to tell by look or feel what the condition of the dampers are.
As was mentioned they are cheap so I keep a spare set in my flight box, you can change them at the field in 10 minutes. On my R50SE I slap in new dampers at the first sign of the blades going out of track, I try not to wait for the full woof & ......
Feel how much the spindle can move in the head inside of the dampers, then change them out with new red ones and feel the difference. Once you know what to look for you can feel when they are starting to get soft.

[pipercub123]

Heli has been fixed, but it has only lasted three outings to the field. Practicing nose in flips she went down. My Raptor doesn't seem to have good power. I'm running 30% nitro and it bogs in fast level flight or when doing flips. I'm guessing I must have too much cyclic input? It doesn't flip that fast, not as fast as the helis I've seen in videos. The OS 50 Hyper has good compression so I doubt it needs a rebuild. Anyone else have these issues? I know the OS 50 is tough, but I'm finding out that it is possible to bog down and I'm not flying too extreme. Perhaps it's time for a 90? I just don't want to eat that crash repair bill!

[Flyinfool]

In your first post you mentioned +/-12 collective.
I have never been able to get a hyper to pull that much pitch when the temp was above freezing.
Once the temperature gets above 80°F I am down to +/- 10° on my R50SE.
You can get away with more pitch if you have good collective management skills.

As far as getting it to flip faster, I set all helies up with the maximum cyclic that the swash will allow, and then run some nice aggressive paddles.

[Toro]

How old is that OS ? It could also be time for bearings....

[Eury]

	Quote: Originally Posted by pipercub123
	Heli has been fixed, but it has only lasted three outings to the field. Practicing nose in flips she went down. My Raptor doesn't seem to have good power. I'm running 30% nitro and it bogs in fast level flight or when doing flips. I'm guessing I must have too much cyclic input? It doesn't flip that fast, not as fast as the helis I've seen in videos. The OS 50 Hyper has good compression so I doubt it needs a rebuild. Anyone else have these issues? I know the OS 50 is tough, but I'm finding out that it is possible to bog down and I'm not flying too extreme. Perhaps it's time for a 90? I just don't want to eat that crash repair bill!

It's something in your setup, tuning, or flying. How long have you been flying, how old is your Hyper? 12deg is fine if you have good collective skills, but too many people set their helis up like that and end up bogging the head because they are trying to fly around with the 12 deg. anything above 9 or so is only used for a fraction of a second to get the heli to start moving, then you immediately back off to the 7-8deg range once it's moving. Once you start putting in cyclic you need to back off even more to keep the head from bogging. If you are bogging out a 50 and it's set up right, a 90 isn't the cure, it'll do exactly the same thing. The cure is to move the sticks while keeping headspeed in mind.

First you need to set your blade pitch, stop using the marks on the side of the frame, they don't mean anything unless you've set up all the links above them to exactly the right dimensions, which handily do not correspond to the dimensions listed in the manual. Get a real pitch guage on the blades, and see what you have for pitch range. On your heli I'd set it up with 0 at center stick, and 10 at the top and bottom until you get better with the collective. You need to get the links adjusted so everything is at 90deg and level at 0, then adjust the position of the ball on the servo arm, and on the collective tray so the pitch you achieve on the top and bottom of the stick is 10 deg.

Cyclic speed is a combination of paddles, blades, and setup. If I were setting up a heli for someone who wasn't experienced in collective management but wanted fast cyclics, I would first put a pitch guage on the blades and measure the cyclic pitch. Put the collective to 0deg, and the blades perpendicular to the boom, and give it full elevator. Read what it says on the pitch guage, you want something around 6-8deg, the higher the number, the faster it'll be on cyclics, but the easier it is to bog down. I'd go 6deg since it sounds like you're learning how to keep the head from bogging (It'll still move quickly, but won't eat up headspeed so fast). Move the blades so they are in line with the boom and do the same thing with elevator, and set the pitch to match what you had the other way. To set the pitch travel on cyclics, the easy way to do it is using your dual rates to turn the travel down, that way you can set different values in different flight modes, ie 6 in normal and idle 1, and 8 in idle 2.

Next you need to address the paddles. On Raptors, TT makes light 3d paddles, they are the green and red ones, and are lighter than the stock blacks. The red and green are the same weight, just different colors, cool guys go for the snot greens. Those will liven up the cyclics quite a bit, if you want more you can leave the plastic insert that slips into the paddle off to make them even lighter while retaining the lovely snot green color. Faster still are the Miniature Aircraft white paddles. These are extremely aggressive due to the weight and design of them, and some of my favorite paddles out there. They are made in both 3mm and 4mm size, you want 3mm. The white paddles are especially sensitive to paddle alignment, if they are a degree off the heli will balloon or dive in fast forward flight, if it dives, move them a tiny bit up, if they ballon, rotate them down. It generally takes me a couple of tries moving the whites up and down before I find the sweet spot, but once you do find it, those are very fast paddles that track really well.

Basically, get what you have setup well, and work on collective management and that heli will do anything you can imagine. Too many people have problems like this and think "If I buy a T-rex or a Vibe, or a 90 this won't happen", and they are wrong. The T-rex and Vibe will fly worse if your setup skills aren't up to par, they aren't nearly as forgiving on setup as a Raptor. Save the upgrade money on fuel, and anything you fly will look good. The Raptor is a great heli that will do more than 99.99999% of the people out there are capable of while being cheap, durable, and inexpensive.

Check out this video of a Raptor 30. Far less power than your 50, and it doesn't bog during all that. That's what collective management will do for you.

YouTube - 3D WITH A RAPTOR 30