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Century Hawk - Falcon - Raven - Predator > Raven bogs inverted
 
 
Cambo
Senior Heliman
Location: Phoenix, Arizona

Okay, so i just got realfight g3.5 and it has really progressed my into inverted hovering. Today i went sub 5ft for the first time ever and was able to hold it there for 2 minutes before i had enough. Regardless, when i go to puch out the heli already sounds like it is maxed out. Not sure if it is running rich or not when it gets upside down. When i went home and looked at my throttle currves i noticed that relative to the carb barrel i am probabley always above 70% throttle on the carb. (I always fittle with the curves at the field). Is this a sign that i need to grab the speed up gear for the raven that puts the gear ratio at 8.6:1 as aposed to 9.2:1


Cameron
07-23-2008 06:32 PM
 
 
Bad Karma
Veteran
Location: UK

Check yout pitch range, make sure its as much negative as it is positive, and check the throttle curves, so that you are using a V curve, if its all as it should be then it may just be the sound it makes in that orientation.
07-23-2008 06:36 PM
 
 
Cambo
Senior Heliman
Location: Phoenix, Arizona

Daa, i forgot to say. The thing just doesn't pull out at a fast rate. I am at 13 degrees i think. Going to the point where she will not bog has very week climbout. Week enough that i am not confortable with it.
I am going to grab the speed up gear and see if that helps me out. Only 8 bucks and a couple hours. Worth a try. All of the raven vids i have seen doing 3d have the speed up gear listed as a mod.
07-23-2008 06:47 PM
 
 
Bad Karma
Veteran
Location: UK

13 degrees!!!

That may be your problem, you could be close to stalling the blades, and even if you arnt, thats a heck of a lot to be asking of the engine.

Drop it down to about +10/-10
07-23-2008 06:54 PM
 
 
FBoss
Key Veteran
Location: Aurora Indiana USA

it is a 50 size.....

The good ole times are now ,000132
07-23-2008 07:10 PM
 
 
Cambo
Senior Heliman
Location: Phoenix, Arizona

yes, but remember, my head speed is slower than traditional 50 size machines. If i go lower than 13, wich i have tried i can get it to wear it will not bog but the pull out is horrific and much to slow for my confort. Upright is better but not by much.

What i am thinking, is if i can get my head speed to be the same or higher with lower throttle settings, ie: 100 60 40 60 100 instead of 100-80-60-80-100 and lower the pitch range to between +-10 i will have better performance because the motor will have more to got to and less pitch when i punch the throttle. At the moment, at the HS i am at the motor has almost no place to got to when the collective is punched because it is using so much throttle to keep the HS between 1900-2000 with the higher gear ratio. Again, after looking at the heli today, my idle 2 hovering setting is above 70% on the barrel, probabley close to 85%. There is just not much more power for the engine to got too. If i am not mistaken, the gear ratio on this bird is higher than a raptor 30.

I am going to experiment with this lower gear ratio of 8:67 and see what happens

Cameron
07-23-2008 07:36 PM
 
 
jschenck
Elite Veteran
Location: La Vista, NE.

Here's what I do. Setup the throttle curve so it's the same on either side of mid-stick. If you make a change on either the high or low side change the other side to match. Bench setup the pitch so it's the same from mid-stick to either side also. Now go fly. If it climbs out faster on either right side up or upside down, adjust the *mechanical* pitch setup with the long links to make the climb the same right side and upside down. You should be close.

Also, I agree you probably want to change the gear ratio to around the 8.6'ish range. I think the Raven is stock at 9.0 or so, a bit high for a 2000 RPM HS and a 50 engine. But even with that you should have a strong climb even with an 1800 RPM HS and 10* collective pitch. This makes me wonder if your engine is running too rich. How is the backplate temp after flying? Not that it's the final tuning criteria but it'll tell you if you are close.

...yep...
07-23-2008 07:58 PM
 
 
Cambo
Senior Heliman
Location: Phoenix, Arizona

I can hold my finger on it for about 2-3 seconds. It is running with alot of smoke. It is possible that it is rich but it is also hot here, around 100 degrees and i worry about going leaner. I think what i am going to do is i am going to get the new gear on, reset everything back to zero, and start from scratch.

Cameron
07-23-2008 08:17 PM
 
 
Bad Karma
Veteran
Location: UK

FBoss, 13 degrees on a 90 is excessive, IMO 11 on a 50 or a 90 is the absolute limit of what is practical.

On my evo 50 I am only running +9/-9 and doing 3D with it, and it climbs like a rocket at 1980RPM
07-23-2008 08:28 PM
 
 
rotormonkey
Senior Heliman
Location: Ottawa, ON - Canada

I have a Raven 50 as well, which I run with 11 degrees pitch in both directions. Even at a lower headspeed my climbout in both directions is just fine.

Since it definately doesn't sound like you're running rich (maybe even a bit lean), I'm inclined to think the pitch you're using is too much, and is bogging the motor. Also, 100 80 60 80 100 seems like a bit of an agressive throttle curve to me. Try 100 70 60 70 100. It will bring down your headspeed in a hover, but may help keep the engine from bogging too much in climbouts.

That's the throttle curve I'm using with the same machine, and it works just fine. Albeit I'm not doing tic tocs with that, but my climbout is very satisfactory.
07-23-2008 08:48 PM
 
 
TulOkFly
Senior Heliman
Location: Tulsa. OK - USA

I would try the 8.6:1 gear ratio.

Just Fly!!!
TRex 450
Blade 400
MX450XS (parts machine now)
07-23-2008 08:50 PM
 
 
the Wasp
rrProfessor
Location: Vt

you really should be asking this on the Century page !!


first, click on and read the link below, make sure your throttle is setup RIGHT,, then move on to the Collective/Cyclic setup,,

13 degrees is to much unless you got some hot-power there,, and, you may be running a lower HS than you really think,,

with the Gray Counter gear (8.736) and the MP2 with 20% nitro (with a good setup) 11 degrees is a good setting,, but you did not say what Muffler/Pipe,,

I'm betting something somewhere in your setup is wrong ,,

1 thing you have to be careful of when setting your Pitch is to make sure your blades are aligned well in the grips, if the blade get bumped between reading negative and positive then you will set it up wrong,,

another thing that will screw things up is if your sub trim is really high,,

the best thing I can tell you to do is to get the Throttle Linkage right, and make 100% sure your cyclic servos arms are 100% level at mid Stick/50% curve/0 pitch, Sub Trim 18% or lower, Throttle Linkage setup RIGHT,,, and even better~ buy a Multigovernor ,,

did I tell you to setup the Throttle Linkage RIGHT, you can loose a lot of power if your T-linkage is serup wrong !!..

http://www.ronlund.com/throttle.htm

Jim
Buzz Buzz Buzz
07-23-2008 09:35 PM
 
 
Cambo
Senior Heliman
Location: Phoenix, Arizona

I believe the muffler is a SAB 5 hatori but i can't be sure. The pressure system is standered with muffler pressure and header tank mounted as closer to carb as possible.

I am going to also point out that i have this thing on +-11 in idle 1 using almost the same throttle curve and while it holds climouts a little better, much slower, it still bogs significantly inverted and while transitioning to any manuever.

Oh, and i have done the proper throttle setup.

Also, i am interested in the uniflow system, how exactly does that work?

Cameron
07-23-2008 10:24 PM
 
 
RICH.L
Key Veteran
Location: east springfield p.a.

Best thing I ever did on my raven 50 was the speed up gear!

And the hatori jk pipe was also well worth the money!!

rich
07-24-2008 01:02 AM
 
 
Cambo
Senior Heliman
Location: Phoenix, Arizona

Okay, so this is what i have done for tomarow. Heli is setup for a max pitch range of +-10 degrees. The cyclic range for roll and pitch is 6 degrees. The fuel will be 20% coolpower. The idle up pitch curve will be 100-65-45-65-100. I also significantly bumped up the cyclic to throttle mixes.

I actually did not have the throttle servo setup as i thaugh and the link that wasp posted was very helpful. I thaught he was refuring to making the throttle servo travel faster than the cyclic but after i read the post i went and looked at the geomotry of my setup and it was WAY off. It took me along time to get the thing perfectly setup concidering i had to use subtrim to prevent the servo from overdriving

I was actually pissed at my self to find out that the Raven doesn't need the really long servo horns to get decent cyclic pitch range. So this entire time was putting a large extra load on the servos with such large control arms. Regardless i put shorter ones on to limit the range and give the servos better mechanical advantage.
07-24-2008 04:37 AM
 
 
Bad Karma
Veteran
Location: UK

Good, it will probably feel like a completely new heli by the sounds of what you have done.
07-24-2008 02:53 PM
 
 
Cambo
Senior Heliman
Location: Phoenix, Arizona

Well, i just got back from the field and i just don't know what to do. With the pitch set at +-10 the engine bogs while going up. At first it seems to go up at a quick rate but then you can just here the engine slow and slow and slow. Inverted is worse. Before, with -13 in there the heli would pop out fast enough before it bogged to get out of trouble. With -10 it is like watching grandma pull a shoping cart at safeway and the engine just slooooowwwwwwss. I fittled with the throttle curves and tried lower pitch range. It wouldn't bog eventually but my guese is it is around 8degrees of pitch. I fittled with the mixture with no luck. What bothers me is there is absolutley no power to transition through menuevers. I have been practicing tictocs using alot of collevtive managment on realflight and just can't get the Raven to do more than 3 before the motor sounds like it is about to die from to much load. When i transition to inverted flight the blade slows so much that i it is almost hard to stop he heli from falling from the sky. You can blame my throttle curves and my mixing or my tunning but I just don't feel the engine is cutting it. I remember my os37 powerd hawk climbing out at almost twice the rate this thing is climbing. In realflight, i can just power through every menuever, but i find it almost more useful to practice using the helimax AX Cp in the sim rather than the Dolphin 50.
07-24-2008 05:00 PM
 
 
FBoss
Key Veteran
Location: Aurora Indiana USA

Sounds like it has to be motor tuning issue. M2C

The good ole times are now ,000132
07-24-2008 05:05 PM
 
 
Cambo
Senior Heliman
Location: Phoenix, Arizona

I just don't see how, if the engine is idling and transitioning smoothley and I am as lean as i feel confortable going were is the gobbs of extra power that i am seeing both in videos and realflight coming from.
07-24-2008 05:08 PM
 
 
TulOkFly
Senior Heliman
Location: Tulsa. OK - USA

I would try changing the gear ratio to the 8.6:1.

I always thought that the 50 standard ratio is the 8.5:1 (The Raptor 50 runs a 8.5:1 ratio), so I think that is probably the issue.

Just Fly!!!
TRex 450
Blade 400
MX450XS (parts machine now)
07-24-2008 05:44 PM
 
 
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Century Hawk - Falcon - Raven - Predator > Raven bogs inverted
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