H9 Extra 260 crashed after violent, uncontrollable tailspin.....

[martin18152]

This answer sounds simplistic; however, I think what happened here, assuming no pilot error, is a un commanded movement or lock up of the rudder servo. I have had a rudder servo momentarily lock up due to intermittent regulator failure; fortunately this happened on the ground. There was only one regulator, big mistake, no redundancy. I have also seen servo gears lockup and break lose in an intermitted fashion, I have a servo on my bench right now that’s locked up completely. You might take your rudder servo or servos, and work them out on the bench, using the extensions, regulator, and batteries that were on the plane, and see if you can make them fail or lock up.

I also fly on one rate, no low rates for landing. What I do is lay the low rate linear curve over the high rate expo curve. I then adjust the high rate expo curve so that it lies on one half of the linear low rate curve – one quarter on each side of neutral. If you don’t get crazy with the sticks, especially the rudder, you have the linear low rate precision for landing, and still have the high rates for 3D flying. If you have a 14mz this is very easy to do, I don’t know about other radios. I don’t like throwing a lot of switches; during a dead stick it’s easy to forget to throw the low rate switch.

[RCFanatic12]

	Quote: Originally Posted by Black Bird
	Did you check out 13 year old Hugo huckin the hell out of his Extra 260. The more you defend your position, the more I beleive it was pilot error. 30% expo on high elevator, WoW. I also learned how to fly with zero exponential. I flew like crap. But that was me.

	Quote: Originally Posted by Black Bird
	We are trying to help. Please try to remain consistant with your posts. Inexperience, incorrect control inputs, and improper radio setup all point to pilot error. It is not a bad thing, you just need more practice and guidence. Have fun with your new Extra and PLEASE dial up that expo a little. BB

I understand that everybody is trying to help and I greatly appreciate everyone's input; I apologize if I sound frustrated or sound rude. Since this thread has gotten so much attention, I think my explanation of the crash has been misunderstood.

My inputs (slight aileron in the downline) was something that this plane had always handled smoothly over the past year. The fact that the plane started going out of control while I wasn't doing anything different that could or should cause it to happen is why I got defensive about pilot error being the cause. Understand that I had successfully recovered the plane from the maneuver many times before it finally went in, which I said in my original post.

When I originally stated that pilot error eventually caused the plane to crash during the maneuver, that was true. My inexperience as a pilot in how to properly recover the model from the out-of-control situation eventually caused it to crash even though I may have saved in the past. And yes, some of you may believe my radio setup was a problem, but understand that I successfully flew this plane for over a year and well over 100 flights without a single incident. I just don't comprehend how my radio setup or lack of expo could suddenly cause such an incident to occur.

[RCFanatic12]

	Quote: Originally Posted by RTK
	That is why I mentioned earlier that I think it has to do with some freak electronic problem when put into a down line. Something grounding or shorting out, causing this weird behavior. He mentioned it was repeatable and had done this many times. Nothing else makes sense either.

The only thing is that the plane would fly smoothly out of the downline if all controls were deadsticked. The second aileron was applied, no matter if it was only 10% throw or full 100% throw, everything went crazy.

	Quote: Originally Posted by flyin4fun
	almost sounds like your elevator halves were working opposite of one another like normal ailerons

Based on the characteristics of the model in the downline, that was how it looked, but on the ground and during normal flight, they functioned normally.

[RCFanatic12]

	Quote: Originally Posted by martin18152
	This answer sounds simplistic; however, I think what happened here, assuming no pilot error, is a un commanded movement or lock up of the rudder servo. I have had a rudder servo momentarily lock up due to intermittent regulator failure; fortunately this happened on the ground. There was only one regulator, big mistake, no redundancy. I have also seen servo gears lockup and break lose in an intermitted fashion, I have a servo on my bench right now that’s locked up completely. You might take your rudder servo or servos, and work them out on the bench, using the extensions, regulator, and batteries that were on the plane, and see if you can make them fail or lock up. I also fly on one rate, no low rates for landing. What I do is lay the low rate linear curve over the high rate expo curve. I then adjust the high rate expo curve so that it lies on one half of the linear low rate curve – one quarter on each side of neutral. If you don’t get crazy with the sticks, especially the rudder, you have the linear low rate precision for landing, and still have the high rates for 3D flying. If you have a 14mz this is very easy to do, I don’t know about other radios. I don’t like throwing a lot of switches; during a dead stick it’s easy to forget to throw the low rate switch.

Hmmmm.... I might have to play around with doing a setup like what you've got. Sounds interesting and something that might be good for me, since I find it a hassle flipping rates during flight.

As far as the rudder servo, I'll play with it more extensively when I get the chance. I quickly checked it last week and ran it under power and everything appeared to move smoothly and it still had strong holding power, though I still agree that the rudder servo is a likely cause. I'll update later after I check it out.

[dqman40rock]

I had a qq 50
It would get into these death spins. I had it nose heavy. It wouldnt fly out of a up right harrier very well. It crashed trying to do that.
My vote is a touch nose heavy. Its all it takes on some planes.

[dubd]

	Quote: Originally Posted by RCFanatic12
	The only thing is that the plane would fly smoothly out of the downline if all controls were deadsticked. The second aileron was applied, no matter if it was only 10% throw or full 100% throw, everything went crazy.

That really sounds like you were accidentally feeding in elevator input and causing the plane to snap, which is possible with the little amount of expo that you have.

[DKjens]

RCFanatic12,

I flew helicopters for two years before switching to fixed wing. I flew all my smaller models on one rate (high rate) all the time and with little expo and I never had problems. Larger airplanes is a different story though, it takes very little extra throw on the elevator to go from a flying condition to a stalled condition, and with your setting that may just be a nano degree on the stick.

I didn't take any of your response in a negative way, and I appreciate that you handle my input in the same way.

Cheers,

[Black Bird]

On the downline, the Extra is in a stall conditon. Only thing left to incipitate a spin is adverse yaw. Are you flying with aileron deferiential. If you are not using deferiential, aileron input will cause adverse yaw which will incipitate a spin. With the little expo that you had on the elevator, it is concievable that you were feeding in elevator with you aileron inputs.

The last thing I will suspect is the radio equipment. It is possible that you were suffering from signal interference from the engine. Signal interference will cause the uncontrollable situation you discribed.

[Black Bird]

It is time to say goodbye to my Extra 260. I will be selling it at this years auction. It has an OS 160FX, JR servos, Fromeco reg and batt with a JR heavy duty switch. The AUW is a little under 12lbs. It is a fanominal aircraft. I had mishaps, but they were all pilot error. Fortunately I did not have the issues discribed in this thread.

Hanger 9 Extra 260 pictured with a 3MM TOC 53cc Mej 22x8

[HUNTERNFLA]

	Quote: Originally Posted by go29kev
	the guy who tought me how to fly many years ago had the most simplest way to balance any plane to big to use a CG stand with and he used this methed on all of his planes. and that was to use the simple string methed. by placing the string in the center of the plane left to right and at the right cg location front to back u can get the all over balance including side-to-side and front-to-back all at once. i have used this methed on all my planes 90 sized and up. even on my 27% & 30% extras and also on my 1/3 scale f4u corsair. and all have test flew with very little trim changes. what a lot of people forget about is left and right balance is also important to a great flying plane. i mark the cg on the correct points on the inside of the body and with a piece of alum. i make a bracket that has a eyelet in it, i mark the center of the piece of alum and the center of the body(side to side) and line the marks up keeping the eyelet centered on the cg mark and in the center of the plane. and useing a good qualty string i hang it from the work shop rafter keeping the table under the plane just as a safty measure. on the top end of the string i have a d-clip for easy hooking and unhooking. i have done this with planes weighing up to 25#'s (the heavest one i have so far is 25#'s) here is some pics to try to help show ya how its done. and if you want to get it perfict then after you get it level left to right then you can sit the hatch on the plane just to the side of were it goes but in the correct position front to back so that you can get the effect of the hatch if any. but this is a very simple way to balance your planes that are to big or to heavy for the standard cg balancer and unlike them you can get the left to right at the same time. hope this helps you understand and you find it as simple and easy as i do. you doint need all the complacted ways a simple string, ruler, and a few little pices of scrap and you can get the perfict balanced airplane and by taking a few mins (i can do it this way and be perfect in 10-15mins) you can only come out good. this has worked for me and my dad and my granddad for the last 23 years so i beleave in it.

ILL GIVE IT A TRY THANKS !

[1bwana1]

Just saw a thead on another site, where the tail section failed in flight. The fuse cracked just in front of the vertical stab. This could cause your symptoms, if the same thing happened to your plane.

[HUNTERNFLA]

	Quote: Originally Posted by go29kev
	the guy who tought me how to fly many years ago had the most simplest way to balance any plane to big to use a CG stand with and he used this methed on all of his planes. and that was to use the simple string methed. by placing the string in the center of the plane left to right and at the right cg location front to back u can get the all over balance including side-to-side and front-to-back all at once. i have used this methed on all my planes 90 sized and up. even on my 27% & 30% extras and also on my 1/3 scale f4u corsair. and all have test flew with very little trim changes. what a lot of people forget about is left and right balance is also important to a great flying plane. i mark the cg on the correct points on the inside of the body and with a piece of alum. i make a bracket that has a eyelet in it, i mark the center of the piece of alum and the center of the body(side to side) and line the marks up keeping the eyelet centered on the cg mark and in the center of the plane. and useing a good qualty string i hang it from the work shop rafter keeping the table under the plane just as a safty measure. on the top end of the string i have a d-clip for easy hooking and unhooking. i have done this with planes weighing up to 25#'s (the heavest one i have so far is 25#'s) here is some pics to try to help show ya how its done. and if you want to get it perfict then after you get it level left to right then you can sit the hatch on the plane just to the side of were it goes but in the correct position front to back so that you can get the effect of the hatch if any. but this is a very simple way to balance your planes that are to big or to heavy for the standard cg balancer and unlike them you can get the left to right at the same time. hope this helps you understand and you find it as simple and easy as i do. you doint need all the complacted ways a simple string, ruler, and a few little pices of scrap and you can get the perfict balanced airplane and by taking a few mins (i can do it this way and be perfect in 10-15mins) you can only come out good. this has worked for me and my dad and my granddad for the last 23 years so i beleave in it.

THIS WORKED GREAT THANKS