badz

My Feedback: (1)

Ok I'm pretty new at rc airplanes but I've been flying a Arrow and LT40 both fly great with no problems...I purchased a great planes cg machine and balanced two new planes a us aircore colt and hobbistar mkiii 60...both planes nose over on takeoff's but according to the cg machine are perfectly balanced...set on the machine with both rods in by fuselage and at the cg as recommended....the hobbistar manual states they needed 2.5pz's of weight for protptype on tail mine has almost 4oz's of weight on tail.....but noses over bad...also both planes when nosing over wing tip to the left.....I haven't removed the weight and tried unbalanced cause I guess this would causse a problem...I have however balanced the Arrow in the same manner and it nosed over on takeoff and wintipped to left...I removed weights it flew?....Any suggestions? As I'm seeing this now the Great Planes CG machine sucks and doesn't work.

Broken

Your statements are a bit confusing- A trike gear has a *tough* time nosing over unless the nose-wheel is turned sharp while on a high speed roll. Nose-over is possible on a tail-dragger if the man gear is to close to CG etc-

The CG machine is as simple as it gets when it comes to balance point- The only real issue is in the actual application of it (but that's up to you) Its not a perfect machine but the human factor is usually a good place to start when problems arise.. *RTM*

For troubleshooting I would start with the takeoffs- if both planes exhibit problems during roll-out, and both problems are similar than look at your nose-wheel setup (is it to sensitive)?

My friend always used to flip to the left because his thumb would flip the throttle slightly left while throttling up- took him a year to get it under control...

badz

My Feedback: (1)

this problem though has only happend on planes balanced off this machine...I did rtm and did exactly as they claim used exact cg measurements even calculated my own to double check and still exhibt the left handed wing tipping on takeoff roll on both planes....one plane is a tail dragger other is tri gear, also I'm taking off on macadam...right now as it stands the hobbistar 60 has a supertigre 61 2 stroke on it and i had to add 4.5oz's of weight to the tail to balance this plane but I get left handed wing tip roll overs on takeoff, I can zip up the runway fine soon as I apply some elevator it wing tips over? Also tried moving weights to different locations..ie center of real fuse and so on still have same problems. Thanks for the tips tho I'm going flying tomorrow will try some out and see what happens maybe even video the takeoffs and post might help some.

SERAFIM

Have you balanced the plane laterally? That means holding it from the bottom of the rudder and the prop shaft and checking if it tends to drop the same wing every time. If it does you have to add weight to the opposite wingtip until it is balanced. If that is ok, maybe you do not have enough airspeed when you apply up elecator and so you end up with a tip stall. That can happen because the center of the wing gets the air from the prop, so one tip can stall when you take off. Try letting it gain more speed on the ground before you rotate. If none of those help, you can try building some washout in the wing, which prevents tip stalling

Ed Smith

Are you holding some right rudder and a touch of right aileron on takeoff?

Ed S

MinnFlyer

My Feedback: (4)

Has either plane actually flown? Maybe you have a warped wing.

CAPtain232

My Feedback: (40)

I will pretty much guarantee you that you do not have a problem with the GP CG MACHINE. No offense intended, but it has to be something you are doing. It could possibly be the way you are using the CG MACHINE. Or as some are implying, it is the way you fly or something wrong with the plane.

If you can, set one of your planes on the CG machine and take a close up picture of the way it is set up. Then post the picture and give a detailed description of what you think it shows.... Maybe we can find something wrong.

The only problem that the GP CG MACHINE might have is the pivots might be a litty sticky and that is still usually not enough to cause problems.

Crash90

My Feedback: (17)

Did you double check to make sure you dont have your elev servo reversed?

Smooth Controller

Crash90,

That would do it every time!

Stick Jammer

Does this seem like an awful lot of added tail weight for this plane to anyone besides me? Something sounds out of whack.

badz

My Feedback: (1)

Ok...frst answer...no neither the aircore nor the hobbico plane have flown when balanced on the cg machine...second answer....the wings aren't warped....thrid answer....they are lateraly balanced. My arrow plane has however flown and once balanced on the cg machine it wing tipped to the left and rolled over...I removed the weight the plane flew again....servo's are not reversed....I'm not totally clueless to airplanes...rc ones maybe I am a aircraft sheet metal mechanic but pretty new to rc planes...I only bought the cg machine cause I thought it'd be a benefit to me...I will post some pictures asap...heading out of town for a few days but will have takeoff video and cg pics for suggestions...at this point I'm hoping you pro's can help me out everyone locally seems to be stumped....oh and btw the planes wing tip to the left very fast within 10-15 feet of powering up the engines....I'll post pics of planes...engine alignments and all when I return, thanks so far people

SST

My Feedback: (2)

Are you easing the power on, or just hammering it from the get-go? Most planes, especially taildraggers, will torque steer if power is applied too fast.

britbrat

Sounds like tail-heavy to me. The planes seem to be balooning off the runway, stalling & spinning in.

DBCherry

My Feedback: (4)

Sounds more to me like the planes aren't ever getting into the air.

I'm reserving my opinion until we get more info.
Dennis-

air mail rcu

Sounds like to me you are making the planes tail heavy. How you are doing this I can't tell till I see some pics on how you are using the cg machine. I only flew one tail heavy plane. It took off real fast turned left (180 degrees) and came right at us. Totally uncontrollable.

badz

My Feedback: (1)

OK I tried balancing a dazzler and it wont balance at all on the cg machine....no matter what amount of weight is added the plane either drops to the nose or tail there is absolutly no in between. I'll post more pics of planes on the cg machine and video of takeoff's if weather lets us fly tomorrow.

http://www.badz.net/cgpics

Stick Jammer

First off, get rid of that plastic hose you have on the muffler. It won't hold up anyway, the heat will melt it. Invert the Dazzler on the balancer, it will be slightly easier to balance in that position. Your problem is not the CG Machine, some planes will be very touchy to balance but it will balance.

badz

My Feedback: (1)

Thanks, inverting the dazzler made it balance out and yeah it was touchy...tomorrow will tell the story will video takeoffs of all 3 problem children

jettstarblue

Wheels too tight? Grass too long? Where exactly are you balancing these planes? About 25% from the L.E.?
Sorry, just some questions.

RC-Captain

I have flew a total of 10 airplanes and have never had to balance one them .

DBCherry

My Feedback: (4)

Well, this thread is 4 months old and badz has never posted again, so I'm guessing he solved his problem.

RC-Fiend,
One of these days you're going to wish you'd balanced your planes.
Dennis-

air mail rcu

How long were the flights?

RC-Captain

I guess I am lucky.

badz

My Feedback: (1)

Actually yes all whom posted helped solve the issue with a few planes of mine mainly the post from CAPtain232. My CG Machine had the balls sticking slightly it wasn't alot but was enough to give me false enough readings to allow misbalancing of the planes. Thanks to everyone who posted you all where a great help

bentgear

Besides having free movement in the ball and socket joint you also need to remember to turn off any ceiling fans and make sure the AC/Heat duct is not blowing directly on the plane while balancing.

The advantage of using a CG Machine over fingers is you are able to add small amounts of weight till you get it right without constantly relifting the plane.

Ed M.