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Fast Lad Performance . Esprit Model . Thunder Power RC

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Century Hawk - Falcon - Raven - Predator > First loop, second crash....
 
 
Deom
Heliman
Location: Guadalajara, Jalisco.

Hi all, I had my second crash today, first one was due to mechanical failure, lost a screw on the tail rotor, my second one, I mean I can't explain it but I kind of enjoy it!!!! I was trying my first loop, good forward speed, nice rotor speed went for it, made the loop (small radius, closed loop) but lost a huge amount of head speed, I was high (around 70 ft) and the heli went down, it went on an upright position, but as I lost so much head speed I just couldn't stop its downward motion.
I lost the landing gear, had a boom strike (lost boom and tail rotor shaft), some control rods popped out so I have to check the servos, but strangely the main blades are OK.

What's my question to all of you? Why did I lost all rotor speed? I changed pitch really quick during the maneuver but I was in idle up 2 (100-70-60-70-100) after playing with the throttle curves I finally had nice head speed... so what went wrong?
What do you recommend to check on the helicopter?

Thanks for your answers, even after the crash I was happy because I found the balls to do it!!! That loop felt great!!!

David.

If a problem has a solution then why worry, and if it doesn't have any.... then why worry!
05-04-2008 01:53 AM
 
 
Furious Predator
Elite Veteran
Location: Kitchener, Ontario, Canada

what machine, engine, and blades?

Shawn
Team Leisure-Tech
05-04-2008 10:46 AM
HOMEPAGE  
 
 
Ray Fernandez
Key Veteran
Location: Guam (U.S.A.)

Another question.......were you doing the loop into the wind? How is your throttle curve at Idle 2? Is it "V" shaped?

Ray Fernandez - GUAM
05-04-2008 12:36 PM
 
 
Deom
Heliman
Location: Guadalajara, Jalisco.

Hawk pro, OS37, stock blades, V shaped idle up...

If a problem has a solution then why worry, and if it doesn't have any.... then why worry!
05-04-2008 02:28 PM
 
 
Cambo
Senior Heliman
Location: Phoenix, Arizona

did you notice any notible difference in engine noise. It could be going lean or rich and loosing a bunch of power.
05-04-2008 03:02 PM
 
 
snobdrs
Senior Heliman
Location: coatesville,pa-usa

well lets look at it like this. You probably have good headspeed upright so the top part of you curve is close. Check it at half stick, make sure you speed is good here. You could even have it a little fast at half stick which can help if you bog on either end. If all seems good check your pitches on the negative side. make sure they match your upright pitches. When i check my pitches i pull on the trailing edge of the blade to take the slop out( pull up for positive and down for negative).

Support your local hobby shop
05-04-2008 03:14 PM
 
 
az_heliguy
Senior Heliman
Location: Florence, AZ

i would also suggest that if your not running any type of headspeed gov, to add some ail/elev -> throttle mix in the radio, so any type of input in the ail/elev would give a little more throttle, start at 25% and see how she goes from there... especially if going into a closed loop like that. that much torque against the blades is gonna slow em' down. when i go into a closed tight loop in id1 or id2 at 1950 or 2100 headspeed, it slows for a quick second, but the gov picks it right back up...
05-04-2008 09:38 PM
 
 
Deom
Heliman
Location: Guadalajara, Jalisco.

I was thinking about my crash today, the helicopter was really far away and I couldn't hear the engine and see the smoke, I'm not sure if the engine stopped when doing the loop, as I was with full throttle but no response. But as I disassembled the fuel tank today I realized the brass tube that goes to the muffler is rotten, full of holes and cracks on the section that goes inside the tank, so I have pressure but my theory is that because of this the engine stopped when I was inverted. Could that be a reason for the engine to stop?

D.

If a problem has a solution then why worry, and if it doesn't have any.... then why worry!
05-04-2008 09:40 PM
 
 
az_heliguy
Senior Heliman
Location: Florence, AZ

i would say no... as long as that tube goes into the fuel tank, there should be some pressure. are you running a header tank though?
05-04-2008 10:00 PM
 
 
Deom
Heliman
Location: Guadalajara, Jalisco.

No Header tank, is it a must? You can't go inverted without one?

If a problem has a solution then why worry, and if it doesn't have any.... then why worry!
05-05-2008 12:11 AM
 
 
az_heliguy
Senior Heliman
Location: Florence, AZ

i wouldnt say that its 100% necessary, but a lot of these helis main fuel tanks vibrate to some degree and if you go inverted and are at 1/2 tank, there is a change that the heli can start to lean itself out by getting air bubbles in the fuel line, at least with the header tank and it always being full, you wont have that problem...
05-05-2008 12:20 AM
 
 
centuryman
Senior Heliman
Location: deerriver,mn usa

if you combine a lean setting with foamed up fuel and a flip thrown in the mix, it would explain a engine bog especialy on a 37 if you puched to much negitive pitch on the top of the flip.37's are easy to bog to begin with and then there is the cyclic to throttle mixing on my nitros i set the mix to give full throttle when doing flips and rolls.are you sure you didn't stab in to much negitive pitch at the topof the loop.It's easy to bog a 50 even by doing that.
05-05-2008 12:28 AM
 
 
az_heliguy
Senior Heliman
Location: Florence, AZ

i would say to richen the hig end about 2/3 clicks counter clockwise and add the ail -> throttle and elev -> throttle mixes in the radio. i had my old hawk pro with an os .37 and had to do it, now the owner of that heli has the same mixes in his radio...
05-05-2008 12:35 AM
 
 
Deom
Heliman
Location: Guadalajara, Jalisco.

My cyclic and pitch inputs were everything but smooth, I'll add throttle-cyclic mixing... but how much?
Torque tubes and header tanks are out of stock at heli-world, do you know other internet store to buy them? As I explained before, the brass tube that goes into the tank and connects to the muffler is full of cracks and holes, useless, the mixture of fuel and exhaust gases was too much. Is there any other material option for that tube? I'm just on my second gallon and I was expecting more quality on the materials.

If a problem has a solution then why worry, and if it doesn't have any.... then why worry!
05-05-2008 12:49 AM
 
 
Ray Fernandez
Key Veteran
Location: Guam (U.S.A.)

Any air that is not supposed to be in the fuel system when the engine is running, will cause a leaning effect, thus causing your engine to overheat and lose power. Replace all the lines and check for any more pinholes and cracks in the fuel lines.

Ray Fernandez - GUAM
05-05-2008 02:11 AM
 
 
centuryman
Senior Heliman
Location: deerriver,mn usa

set your mixes so that the throttle goes wide open when you give a full cyclic input.
05-05-2008 02:56 AM
 
 
Blade_Master1
Veteran
Location: Canada

Deom
when your done flying empty your fuel tank. the left over exhaust gases will eat the tubing,

http://www.leisuretech.ca/index.html

lots of good info here

I believe 25% cyclic to throttle mix same for elevator to throttle

make sure you overdrive the throtle servo while mixing

A better way is either learn collective management or get a governor


.

You can say what you want , Just don't say it here!
05-05-2008 06:29 AM
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Century Hawk - Falcon - Raven - Predator > First loop, second crash....
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