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mudbeast2 03-02-2014 09:06 PM

Take off help
 
Hey Guys,
I have a Airfield 800mm Corsair warbird. I know it is not the best quality plane but here is my question. When I go to take off she lifts up about 2 feet then makes a hard left back to the earth. What I have noticed is the tip of the right wing is 3/8 of an inch higher than the left. Being that it is foam can that be adjusted? I am using a spectrum DX6i with a Orange receiver that has flight stabilizer. Any advise will be helpful.

max2112 03-02-2014 09:56 PM

mb2,
If your setup has a stabilizer built in it is very important that your model be perfectly flat and even when you first power it up. If your right wing is a little bit (& 3/4" is more than a little bit!) higher than the left when you first power everything up, then that that is the normal reference that your stabilizer will try to keep you at.

My suggestion: turn off or remove the stabilizer. If possible, true your model on the bench. make the right wingtip the same height from the landing surface as the left. Make all of the control surfaces flat and even with the upper portion of their wing/tail surface.

Fly (or have an experienced pilot) your model and set the trim tabs on your controller to allow it to fly straight and level at 70% throttle with no input to the controls.

Then you can put your stabilizer back on initialize it when the everything is set up correctly.

CHELLIE 03-02-2014 10:05 PM

Quote:

Originally Posted by mudbeast2 (Post 941334)
Hey Guys,
I have a Airfield 800mm Corsair warbird. I know it is not the best quality plane but here is my question. When I go to take off she lifts up about 2 feet then makes a hard left back to the earth. What I have noticed is the tip of the right wing is 3/8 of an inch higher than the left. Being that it is foam can that be adjusted? I am using a spectrum DX6i with a Orange receiver that has flight stabilizer. Any advise will be helpful.

I Had a GWS Corsair that did the same thing, the wing was twisted, I played hell-o trying to find that problem, lay the wing on a flat surface with some weight, and use rulers to get a good measurement of the wing, use a hot air gun or steam to heat and twist the wing back into shape, hope that helps, Chellie

JetPlaneFlyer 03-02-2014 10:10 PM

On the assumption that the controls are working in the right direction (right aileron stick makes the right aileron go up, and vice-versa) 90% of the time this sort of problem would be caused by 'pilot error' due to inexperience flying a taildragger warbird type model. Tail-dragers will almost always tend to swing left on take off, you need to correct with rudder to keep it straight. If you don't keep it straight and/or if you pull it off the ground with too little airspeed then a left roll is to be expected.

What sort of models have you flown before?

A wing tip that's a little higher when the model is sitting on it's landing gear wont have any serious effect. It's always worth checking that the wings aren't twisted as suggested above, but it would have to be a very bad twist not to be correctable with aileron. My money would be on inexperience with this type of model.

dahawk 03-02-2014 10:25 PM

I had an AT-6 Texan that did the same thing. They need airspeed for proper takeoff. plus, you really do need to be prepared for right rudder. Standard operating procedure. I learned the hard way.

-Hawk

mudbeast2 03-02-2014 11:09 PM

Take off help
 
Please understand I am a total newb. I have a delta ray trainer and have been doing very well with this. I did find the tail wheel all out of shape making for bouncing take offhttp://img.tapatalk.com/d/14/03/03/a6y2ejyd.jpg.


Sent from my iPhone using Tapatalk

Larry3215 03-03-2014 12:10 AM

Quote:

Originally Posted by JetPlaneFlyer (Post 941346)
It doesnt have a gyro stabiliser, so forget previous post,


On the assumption that the controls are working in the right direction (right aileron stick makes the right aileron go up, and vice-versa) 90% of the time this sort of problem would be caused by 'pilot error' due to inexperience flying a taildragger warbird type model. Tail-dragers will almost always tend to swing left on take off, you need to correct with rudder to keep it straight. If you don't keep it straight and/or if you pull it off the ground with too little airspeed then a left roll is to be expected.

What sort of models have you flown before?

A wing tip that's a little higher when the model is sitting on it's landing gear wont have any serious effect. It's always worth checking that the wings aren't twisted as suggested above, but it would have to be a very bad twist not to be correctable with aileron. My money would be on inexperience with this type of model.

I agree with JPF. Its probably not the wings causing the problem. The tail wheel wont cause that problem either.

It is probably some combination of taking off at too slow an air speed (stalling) and not using rudder correctly to keep the model straight.

It could also be an improperly set up gyro stabilization - or it just doesnt work. Do you have the gyro working in the correct direction on the ailerons, rudder and elevator?

You can test this on the bench.

First - remove the prop!

Then turn everything on and make sure all the controls work in the correct direction when you move the sticks on the tx.

Looking from behind the model with the model sitting on the bench -
When you move the elevator stick back, the elevator goes UP.
When you move the rudder stick to the right, the rudder moves to the right.
When you move the aileron stick to the right the right aileron goes UP.

Next, hold the model in your hands for the following tests. Be sure the stabilization is turned ON.

Starting from holding it level, quickly rotate the model to the right so the right wing drops while the left wing goes up. Watch the ailerons carefully. As the right wing drops, the right aileron should move DOWN and the left aileron should move UP. When you roll the model to the left, the opposite should happen. As the right wing goes UP the right aileron should go UP as well.

Test the elevator by making the model pitch UP and down. When the model pitches UP - nose goes up/tail goes down - the elevator should move down and vice versa.

Rudder is the same. When the models nose moves left while the tail moves right (as in a left turn), the rudder should move to the right. The opposite will happen in a right turn.

In other words, with the stabilization turned ON, the model will always try to correct any motion the model takes. When you are holding it in your hands and make it do a right bank, the gyro will try to force a left bank to correct, etc.

Good luck!

xmech2k 03-03-2014 12:13 AM

+1 to the the plane pulling to the left, possibly taking off too slowly. If the Delta Ray is the only plane hope flown before, you've taken a pretty big step up to the Corsair. The DR will probably be able to fly much slower than the Corsair due to several factors, not to mention the AS3X and SAFE. The DR will also not exhibit the pull to the left like the Corsair. The crooked wins you found may factor in a little, but I think you should just learn to use the rudder to keep straight on takeoff and let her get some more speed before leaving the ground.

mudbeast2 03-03-2014 02:35 AM

As always great advise. thank you guys. I will run those test tomorrow. Also I am using a DX6i. Any suggestion's on settings like D/R & Expo? Also I do have Phoenix 4 flight sim. I have been flying a Corsair on there for a while & do pretty well with it. I guess after a bunch of flight sim hours I thought I was ready for the real thing.

mudbeast2 03-03-2014 02:38 AM

Take off help
 
http://img.tapatalk.com/d/14/03/03/ynyrytut.jpg

Here is a pic of the wings being off a little. The motor had come loose so I removed it to make repairs.


Sent from my iPhone using Tapatalk

CHELLIE 03-03-2014 04:45 AM

Quote:

Originally Posted by mudbeast2 (Post 941373)
http://img.tapatalk.com/d/14/03/03/ynyrytut.jpg

Here is a pic of the wings being off a little. The motor had come loose so I removed it to make repairs.


Sent from my iPhone using Tapatalk

Hi :ws: The Best thing to Do here, is to get back to basics, put the Plane on a Flat Table, and take a real good look at WHY the Planes wing is raised up, is it a inproper fit in the fuselage saddle, is the wing warped, is the landing gear not mounted right, find out why, the plane is not LEVEL, and make it Level, set your CG a little more forward, like about 25% from the front leading edge, give the motor about 3 degrees of Down thrust, that will help to load the main wing and stabilize it, Yea I know, A Lot of people Here are going to disagree with me here, but, I have been flying CL and RC airplanes and helies for over 48 Years and have learned a lot over the Years, what I am telling you, WORKS, from 10 different Pilots you will get 10 Different Answers :eek: some good, some not so good :D Take care and have fun, Chellie

solentlife 03-03-2014 07:48 AM

Quote:

Originally Posted by CHELLIE (Post 941344)
I Had a GWS Corsair that did the same thing, the wing was twisted, I played hell-o trying to find that problem, lay the wing on a flat surface with some weight, and use rulers to get a good measurement of the wing, use a hot air gun or steam to heat and twist the wing back into shape, hope that helps, Chellie

How many foamies are NOT twisted somewhere ? I don't think I have had any that are all true ...

My work-around is a Workmate bench - the one with top divided that works as a vice. Put offending article in ... blocks of foam at strategic points and wind her up forcing the twist PAST the neutral point to half of opposite twist. Then waft a hot air gun over the article .. not to overheat but to warm it up. Once warmed ... leave to cool overnight.

Trouble is cure is not permanent ... it creeps back in with varying temps out there at flight site ...

You could if clever - create a 'twist box' that you store the model in.

Nigel

JetPlaneFlyer 03-03-2014 07:55 AM

Quote:

Originally Posted by mudbeast2 (Post 941372)
I guess after a bunch of flight sim hours I thought I was ready for the real thing.

A flight sim wont accurately simulate the left swing that you get on a taildragger. To be honest if all you have is a few weeks flying a Delta Ray under your belt then that's the problem, plain and simple.

If you want my advice it would be:
  1. Dont waste your time trying different rates and expo, playing with down-thrust, or moving the CG from where the instructions told you to set it. All you will do in a trial and error 'lets change random stuff and see what happens' approach is keep crashing and you will soon destroy the model.
  2. Try to find an experienced flying buddy/instructor, then he could get the model in the air for you and help you over the learning curve. A hand launch is one way to avoid the tricky take off part, but hand launches bring their own hazards if you don't know how to do it.
  3. If you don't have an instructor I'd say your best course of action is to put the Corsair away and get more practice flying the Delta Ray (with all the stabilisation turned off). Then graduate to a four channel aileron high wing sport/trainer mode. Then may once you are totally comfortable flying that you could get the Corsair out again.
PS.....the wing sitting low looks to be to be purely because one landing gear leg is bent forward more than the other, causing that side to sit lower. No reason whatsoever to suspect that the wing is twisted. It's nothing that should any great issues on take off and certainly wouldn't cause the plane to roll once airborne.

solentlife 03-03-2014 08:01 AM

Quote:

Originally Posted by mudbeast2 (Post 941373)
http://img.tapatalk.com/d/14/03/03/ynyrytut.jpg

Here is a pic of the wings being off a little. The motor had come loose so I removed it to make repairs.


Sent from my iPhone using Tapatalk

I have plenty of models that after a few T/O's and landings sit like that ... it doesn't have the great effect that you seem to think it does. It's more a cosmetic affair.

There's a couple of misconceptions already in replies .. sorry guys !

a) JPF - he says he has an ORANGE Stabilizer ... I believe that to be the HK one ? The combined Rx / Stabilizer ...

b) That the Stabilizer will induce a roll if wing is left with the slight up one side when sitting on ground ... based on initialisation ... sorry wrong.

The sit if you look closely at the photo shows the axle on the right leg (from our view) is slightly bent UP ... a small bend will be a large amount at tip. It could be that the leg behind the leg cover is slightly bent outward... a bend inward will cure that.

The Stabilizer will want to stay as initialized as long as no input is made ... the model should fly straight and level ... possibly with one tip slightly down but unlikely, as when taking off - control inputs will be made that cancel out initial stabilizer sets. The stabilizer will look to maintain what is input ...

The problem I believe is typical newcomers left bank stall on take-off .. so common as to be the normal action ... watch Youtube and you see so many ..

Here we have a model probably being hauled of the deck too early ... barely flying ... she then drops the left wing as reaction to motor torque / prop rotation ...

What is needed is to let her run on the ground for as long as possible and GENTLY ease her up ... some models in fact because we tend to take-off at WOT will gently climb themselves once good speed attained.

My 2 cents ...

Nigel

JetPlaneFlyer 03-03-2014 08:09 AM

Quote:

Originally Posted by solentlife (Post 941390)
a) JPF - he says he has an ORANGE Stabilizer ... I believe that to be the HK one ? The combined Rx / Stabilizer ...

Sorry, i missed that part of his post.. apologies.

However, it doesnt change my advice, it's still too much model for someone with a couple of weeks flying on a Delta ray.

It does obviously open up a few alternative things to look at though... Does the gyro respond in the correct direction when you move the plane by hand? (i.e. moving the ailerons against the roll)

solentlife 03-03-2014 10:23 AM

Quote:

Originally Posted by JetPlaneFlyer (Post 941391)
Sorry, i missed that part of his post.. apologies.

However, it doesnt change my advice, it's still too much model for someone with a couple of weeks flying on a Delta ray.

It does obviously open up a few alternative things to look at though... Does the gyro respond in the correct direction when you move the plane by hand? (i.e. moving the ailerons against the roll)

No sweat ... just caught my attention ...

Now I don't use the Orange Rx / Stab as it's DSM format ... but surely a combo like that should take it's orientation set-up from channels reverse / normal ? Would seem silly if it didn't.

I totally agree about it being an unsuitable model for move up from a Delta Ray with SAFE techno ... which actually touches on my belief that SAFE etc. is fine - but creates a false sense of ability. A controversial point I know, but then again - I'm old school flyer ... learnt without DR, Expo, Reverse etc. Had to build and fly by stick alone.
But I am quick to USE todays features .... !!

Nigel

JetPlaneFlyer 03-03-2014 10:31 AM

Quote:

Originally Posted by solentlife (Post 941392)
... but surely a combo like that should take it's orientation set-up from channels reverse / normal ? Would seem silly if it didn't.

No, you have to set up the ailerons so they move the correct way when you move the stick, then quite separately you have to set up the gyro gain (positive or negative as required) so that the auto-correction works in the correct orientation.

It's perfectly possible to have the ailerons (or elevator or rudder) set so they move correctly when you move the sticks but the gyro response to be reversed. All gyro units are the same in this respect because response direction not only depends on servo rotation direction (the gyro doent know if the Tx signal is reversed) but on physical orientation of the gyro unit.

dahawk 03-03-2014 01:41 PM

I have a DSM2 Orange 3 axis stabilizer and agree with Jet. First get the control surfaces dialed in mechanically. And yes, it makes a difference on the orientation of the gyro itself. I believe the 'out of box' std is to mount it with the antennas on the forward side, closest to the nose.

The gains can be a bit touchy. Test by looking for opposite reaction to pitch roll and yaw. Do this with quick movements of the plane to dramatize the effect. I fond on my Spitfire that the gains needed to be toned down quite a it, especially the rudder.

I have several warbirds and many if not all are tip stallers. The fullscale versions are also tip stallers for the most part. The easiest of the bunch was the T-28 with it's forgiving dihedral but mine suffered CFIT syndrome. That stands for Controlled Flight Into Tree. LOL

Again, proper airspeed on takeoff is your friend.

-Hawk

mudbeast2 03-05-2014 02:56 AM

1 Attachment(s)
Quote:

Originally Posted by Larry3215 (Post 941358)
I agree with JPF. Its probably not the wings causing the problem. The tail wheel wont cause that problem either.

It is probably some combination of taking off at too slow an air speed (stalling) and not using rudder correctly to keep the model straight.

It could also be an improperly set up gyro stabilization - or it just doesnt work. Do you have the gyro working in the correct direction on the ailerons, rudder and elevator?

You can test this on the bench.

First - remove the prop!

Then turn everything on and make sure all the controls work in the correct direction when you move the sticks on the tx.

Looking from behind the model with the model sitting on the bench -
When you move the elevator stick back, the elevator goes UP.
When you move the rudder stick to the right, the rudder moves to the right.
When you move the aileron stick to the right the right aileron goes UP.

Next, hold the model in your hands for the following tests. Be sure the stabilization is turned ON.

Starting from holding it level, quickly rotate the model to the right so the right wing drops while the left wing goes up. Watch the ailerons carefully. As the right wing drops, the right aileron should move DOWN and the left aileron should move UP. When you roll the model to the left, the opposite should happen. As the right wing goes UP the right aileron should go UP as well.

Test the elevator by making the model pitch UP and down. When the model pitches UP - nose goes up/tail goes down - the elevator should move down and vice versa.

Rudder is the same. When the models nose moves left while the tail moves right (as in a left turn), the rudder should move to the right. The opposite will happen in a right turn.

In other words, with the stabilization turned ON, the model will always try to correct any motion the model takes. When you are holding it in your hands and make it do a right bank, the gyro will try to force a left bank to correct, etc.

Good luck!

Ok, I had some time to go through and check the electronics. All controls are moving in the direction they should be. I also checked the stabilization and that is operation as it should. I did increase the sensitivity slightly, prior to it wasn't moving much at all. I also checked my cg. Airfield says it is 55mm from the leading edge of the wing over the landing gear. With that I made a basic tool and found that the tail was to heavy. So I relocated the esc & battery as far forward as I could & have the Rx almost center of the wing. Still to tail heavy. I added 2-1/4 oz fishing weights just below the motor. It is looking much better but not level yet. Please advise on adding weight & how level should it be? I am doing this with the plane upside down.

thepiper92 03-05-2014 06:44 AM

Toss away their suggestions and measure the wing from the lead to trailing edge, easiest done when the wings exit the fuse. From that distance, multiply it by .25 and .3. Those will be the number of inches or centimetres you go back from the leading edge at the same place where you measured to begin with, meaning if you measured near the fuse, don't mark the points near the tip of the wings. These two values give you a range, the .25 giving a value closer to the leading edge, and the .3 further from the leading edge. In those two ranges, you plane should be safe to fly, and could be a tad tail or nose heavy, but not to the degree of being impossible to fly. Start at the value you derived from the multiplication of .25, and try to make that level when balancing, then fly it, observing the flight characteristics. If it wants to climb in a dive, then the balancing point will be further back from the leading edge (if you balance further back with the same weight, you'll now see the nose drop a lot). You can then try the value from .3, and balance it, with maybe a slight nose heaviness, but not a lot. See how that flies. I never look at the measurements on planes, I find roughly where the balance is in measurements, then balance and see how it flies. In the range of .25 to .3, it will be hard for the plane to fly terribly. The most you'll see is twitchy handling, or a tendency to climb in a dive. These two things aren't fun to have, but the plane will still be flyable...so that you can adjust, instead of smacking the plane up and having to adjust a lot more.

solentlife 03-05-2014 07:03 AM

Quote:

Originally Posted by JetPlaneFlyer (Post 941393)
No, you have to set up the ailerons so they move the correct way when you move the stick, then quite separately you have to set up the gyro gain (positive or negative as required) so that the auto-correction works in the correct orientation.

It's perfectly possible to have the ailerons (or elevator or rudder) set so they move correctly when you move the sticks but the gyro response to be reversed. All gyro units are the same in this respect because response direction not only depends on servo rotation direction (the gyro doent know if the Tx signal is reversed) but on physical orientation of the gyro unit.

Yes now I think aboput it - the Rx doesn't know which way round you will install it ..

I know Gyros well ... from the old mechanical jobs of the 80's through to todays electronic jobs ... only ones I haven't used are the integrated Rx + Gyro ...

Nigel

fhhuber 03-05-2014 08:38 AM

Gyros DO "care" which way they are mounted. Especially true of a 3-axis gyro stabilizer.

If it is upside down you will have 2 controls reversed. Sideways you'll get aileron-vs elevator swapped. At an angle vs wings and fuselage level will get mixed responses.

VERY carefully ensure the gyros are mounted correctly or they will drive your plane any way except the way they are supposed to.

CHELLIE 03-05-2014 10:04 AM

Quote:

Originally Posted by mudbeast2 (Post 941548)
Ok, I had some time to go through and check the electronics. All controls are moving in the direction they should be. I also checked the stabilization and that is operation as it should. I did increase the sensitivity slightly, prior to it wasn't moving much at all. I also checked my cg.Airfield says it is 55mm from the leading edge of the wing over the landing gear. With that I made a basic tool and found that the tail was to heavy. So I relocated the esc & battery as far forward as I could & have the Rx almost center of the wing. Still to tail heavy. I added 2-1/4 oz fishing weights just below the motor. It is looking much better but not level yet. Please advise on adding weight & how level should it be? I am doing this with the plane upside down.

One Basic Rule to Follow with ARF and kit planes is to, NEVER EVER use the MFG suggested CG, Its Normally Always Way Off causing a Tail Heavy Plane, most newbies find that out the hard way and crash their plane and Give up on RC, most of the time a 25% back from the leading edge is a very safe place to start at, it will be a tad nose heavy, but you wont crash the plane on a maiden flight, then adjust the CG from that point little by little, being a tad nose heavy is your friend, I have Never Ever had a planes MFG suggested CG be right, years of Experience has taught me well :ws:.

fhhuber 03-05-2014 11:10 AM

Well... you can't say that the mfgr's CG is always wrong. I have had several ARFs with recommended CG being exactly right.

And when the mfgr's CG is wrong its not always aft. more often its too far forward to ensure a controllable test flight.

A perfect example of too far forward is the Dynam Me-262. Flight testing eventually got the CG back 2 inches from mfgr's recommended location.
Dynam P-51's recommended CG is exactly correct. Further aft is unstable and further forward it won't keep the tail down when landing on smooth pavement. There is no room to move it either way...

JetPlaneFlyer 03-05-2014 11:35 AM

Quote:

Originally Posted by CHELLIE (Post 941562)
NEVER EVER use the MFG suggested CG, Its Normally Always Way Off causing a Tail Heavy Plane, most newbies find that out the hard way and crash their plane and Give up on RC,

Sorry but I don’t agree with the idea of routinely ignoring manufacturers/designers CG advice. In my experience most times the manufacturers recomandetion is perfectly good enough to get the model safely in the air so you can fine tune to your preference. Cases where the recommended CG is so far out as to make the model unsafe to fly are (although not totally unknown) quite few and far between in my experience. Usually as noted above the manufacturers recommendation is on the nose heavy side of safe.

If you want to do a double check the manufacturer then use one of the online CG calculators (the ones that consider the tail in the calc). They are at least based on sound science and will cope with different shapes and types of model. Also check manufacturers web site for any alerts and updates and most reliable of all, get feedback from other owners if you can.

I'd usually put far FAR more faith in the recomendation of the manufacturer of the model rather than some rule of thumb sweeping generalisation (like the 25% 'rule') that for anything of an even slightly unusual layout could be miles out. I could give you plenty of examples where that rule doesnt work.

But each to their own, we are all entitled to our opinions.


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