Control System Failure

[daveb]

Hi,

Had a break in my control system yesterday and I've posted a report and photo's on the Aussie site. I think the parts were locally made so may not apply for you guys. Here's a link in case you're interested.

http://www.asra.org.au/forum/topic.asp?TOPIC_ID=690

Dave

[KenSandyEggo]

Dave, it requires a pasword to get in. Why don't you just copy and paste your post from there to here or share the details of what exactly broke. Thanks. Whoops. Never mind. It says that one is required, but we can read the posts anyway without one. Geez! I'm back. I was able to see the list of threads, including Dave's post, but when I clicked on it, I got the password required message again. Aaaargh! All the other threads can be read except the one in which Dave posted. :confused:

[daveb]

Dave, it requires a pasword to get in. Why don't you just copy and paste your post from there to here or share the details of what exactly broke. :confused:

Sorry Ken, I was trying to save a bit of bandwidth and invite you guys to our site at the same time. Passwords? :mad: Sorry, I thought you could just view stuff. Here it all is:-

Yesterday a section in my control system failed. I will file a report. My concern is that given the parts appear professionally made, the same setup may exist on other gyros.

The system has been in service at least 430 hours to my knowledge. The gyro has significant stick shake that we were addressing.

I have been told that the gyro was flown 'vigorously' by its previous owner, this coupled with the excessive shake may have contributed. I have just had the head serviced and the main bearing was replaced. It was well worn and described in the technical report as 'NFG'. This goes along with the earlier treatment of the aircraft.

Looking at the site of the break. I do not understand why the designer did not leave the tube intact and use a bush or spacer rather than remove material at such a critical point. If anyone has this type of system they might choose to have a look at it.

The failure occurred while Paul (Bruty) was about to takeoff and he noticed an abnormality in the stick pressures. I had just landed in the same Gyro after an hour's flying.

Paul was testing a change in the undersling of my Dragon Wings as a part of our diagnosis of the shake, and offered his experience as a pilot for the test. Needless to say I'm grateful for his skill. I think many other pilots may have rolled the machine given that a control input lost authority.

I intend to replace the whole system now as I just don't trust it. Any input on a way to get flying again, who makes something good for this seat setup etc. is welcomed.

Dave

[Aussie_Paul]

.....to be able to sit down and have an evening meal yesterday!!!!!!!!!!! :eek:

I had flown 3 circuits in Daves gyro adjusting the trim spring, as well as checking the shake after Rosco had blue printed the head.

We had also moved the tail feathers back 18", so these flights were part of a testing procedure. While the head was at Roscos, we fitted an original Bensen head that I had availible. The extra trim spring requirements took me by surprise :eek: until I realised that the torque tube offset was 1" instead of the usual 5/8" that is commonly used in Oz.

Both Dave and I flew the Bensen head with the DW blades.

When I was happy with the trim spring location I told Dave to go for a fly to see what he thought, as he had flown the most hours in this machine. I felt that the shake had not improved much, if any, but the pitch stability was much improved.

When Dave came back after a little over an hour, I discussed with him what he thought. Dave was still unhappy, as I was, with the shake but commented that the pitch stability was certainly improved.

I suggested that we remove the pre rotator, as we had proven the week before the head had been sent to Rosco, that the shake was less with the pre rotator removed.

I also suggested that maybe the undersling should be looked at as the DW blades had a few holes to try. Also there had been comments on the forums regarding BW bldes being a little sensitive to undersling. We decided to change the teeter hole and Dave did that as well as removing the nylon blocks to allow enough teeter.

I taxied out and started the take off roll. I was gentle with these "bastard" :eek: DW blades, and soon they were ready to lift the nose. As the nose lifted I moved the stick forward and thought that it move a little too easily. I kept applying power and the machine started to roll to the left just prior to lift off. I applied right stick and nothing much happend, so I immediately reduced power and let things, and myself, settle down!!!!!!!!

I was surprised with what I head felt!!! I increased speed again and did not let things progress quite as far. The machine seemed so different!!! :eek: I could not believe that a change of the undersling height of 3/4" would be affecting the machine this way.

I taxied back feeling the machine as I went. With the stick full back the roll was normal, as I pushed the stick forward I seemed to lose roll control!!!!!! As I turned to line up I decided to undo my seat belt and have a look. As I moved the stick, the head did not move accordingly!!!!!!!!! :eek:

I taxied back to the hanger and shut everything down, and said, "the control system felt funny"!!!!! :mad: Ater getting out and having a look at the broken bit I sat down and realised that I was correct in my "feeling". I was so glad that I did not "just get it into the air" and sort it out as most of us experienced test pilots do!!!!

When I realised that I had flown with an enourmous amount of backstick pressure, due to insufficient trim spring pressure, and that Dave had flown for an hour just prior, I realised that today was not our day to meet our maker!!!!! :eek: I won't say f**k again, I promise!!!! :eek:

I did sit down for a moment!!!!!!!!! and then relised that second hand machines can, and have been flown by people who may not have had any idea of the mechanical strains that occur. The previous owner obviously had no idea re mechanical things and as such was about to die if he had not sold the machine!!!!!!!!!

Luckily for both Dave and myself, I was able to appreciate what was happening and we did not end up with a wrecked gyro or human damage, especially me!!!! Sorry Dave!!!!! :D
This area of the gyro was painted and could have hidden a crack. Far to many gyros for sale have paint slapped over everything before sale!!!!!!

Aussie Paul. :)

[Brian Jackson]

I'm so thankful you and Dave weren't hurt, and grateful that you and he posted your discoveries of the failure. This should be an immediate "heads-up" for all gyro pilots to examine their machines for similarly stressed parts.

Thanks for posting, and glad everybody's OK.

Regards,
Brian Jackson

[Dean_Dolph]

Whoa, this is scary, scary!

I'm not sure how many control system failures there have been but we lost Bill Parsons and LeRoy Hardee to them and then there was Anthony Spagnoletti's incident a year or so ago where the cyclic came off in his hand just as he touched down. And now this. You guys were fortunate indeed and I'm happy to see that you are still here to post the report.

[Dale Young]

You guys will probably think that I'm CRAZY by doing this , But every so often I will take a few moments of my fly time and dedicate it to flying my gyro directly by the control rods with my hands behind the seat. It is actually very easy and helps me prepare in case my stick somehow malfunctions. Anybody else ever do this?

[MikeBoyette]

Hey Paul,
Watch that "bastard blades" comment we share the same daddy. I am glad no one got hurt. DW's are also very sensitive to being in string. Just a suggestion.

[daveb]

Thanks for the good will expressed here to Paul and myself. One of us will post anything that crops up of relevance.

As a non engineer type of person I'd say that this was the thinnest bit of metal between blades and the stick and it could have been a full tube. Yet it was cut down to a skinny strip that our lives would hang off. In future I'll look out for thin bits in important places! :)

Mike, when I get flying again may I ask your advice on getting the shake out of the system with the 23' DW's? I'm sure its just a matter of the right setup. I like them ;)

Dave

[MikeBoyette]

Dave,
I can give you a few ideas, but you would be better off getting with Dad and he can give you better info than I. I hope you get back to flying soon. I also hope is is safely.

[scottessex]

Dave, just a FYI, when you replace the piece, see if you can make the end so the control rod has a piece of metal on each side of the rod end. It will be more than twice as strong as the one sided mount in a shear load.

[birdy]

Dale Y.,tes I do it some times when I'm git'n bored.Bit hard in the RAF tho.
Have you landed by the rods??,I didn't realise how much extra back pressure is needed at the flare till I had trouble hold'n the rods.

[animal]

Whoa, this is scary, scary!

I'm not sure how many control system failures there have been but we lost Bill Parsons and LeRoy Hardee to them and then there was Anthony Spagnoletti's incident a year or so ago where the cyclic came off in his hand just as he touched down. And now this. You guys were fortunate indeed and I'm happy to see that you are still here to post the report.

Dean I flew with leroy Hardee one month before his death,I went for an hour of training with him, his blades shook so bad, that you could not hold the stick tight,he even told me to hold the stick with my finger tips as it would jump out of your hand if held tighter,I flew with him for only 30 minutes and decided not to fly any longer,I had flown helicopters and had rode in Ed's 2 seat aircommand before that, so I knew there was something bad wrong,all I know is when I asked Leroy about the blade shake, he said thats the way the blades where when he got it from the factory. Leroy was a realy fine guy and I wish he was still with us. but what it boils down to is there is alot more loads on these controls then one might think.
from what I understand about the snowbird, was it had a control end bushing that was threaded into the tube, and that they had sent a note out that they where stripping out and needed a bolt put into it. from what I heard leroy said he was going to do the mod after bensen days. to bad he did not make it home, I will never forget that sick feeling i got when i got a call that night from a pilot freind of mine at bensen days telling me of his death. leroy was a realy nice guy and he put on a great fly-in at mtn city tenn. he is still missed. and am glad our aussie freinds are still with us.

[Aussie_Paul]

Hey Paul,
Watch that "bastard blades" comment we share the same daddy. I am glad no one got hurt. DW's are also very sensitive to being in string. Just a suggestion.

Oops, Mike, it was really meant as a term of endearement, not having a go at DWs. Sorry. :o

Aussie Paul. :)

[MikeBoyette]

Paul,
Just yankin your chain bloke. I've been watching too much of the croc hunter.

[Doug Riley]

That particular construction detail IS a failure waiting to happen. By trimming down the tube to just one wall, you create a cracking point right where the two side walls fade away. You can try to leave a polished radius right at the transition, but it's still a cracking point. Any place where the structure goes from very rigid (the full tube) to somewhat limber (the tab) along a short distance is a natural failure point.

The control system takes a pounding in certain portions of the flight cycle. Routine cruising and maneuvering are probably the least stressful. Taking off from rough ground sends shock loads through the system (the control system is caught between the rotor, which tries to sit still, and the frame, which jumps around). A light touch can relieve these stresses to some extent. Ditto for the hard shock loads caused by rotor flapping.

Use of a stick-activated rotor brake can put more force into the system than routine control movements, too.

There have been other control system failures. Smokey Castner of Florida died when the aluminum inserts in the ends of his pushrods stripped out. He left off the jam nuts that are usually used to secure the rod ends.

A few people have had rod ends break. This is sometimes caused by inadequate clearances between the head of the rod end and the surrounding structure, so that the rod end's stem experiences a bending load somewhere in its range of movement.

[Brian Jackson]

I was reviewing the photos of the failure and, to extend on what Doug Riley was stating, noticed that by removing 3 sides of the tube that broke, the "tab" has no defense against constant twisting loads. The HEIM bolt is off to one side and is trying to "twist" the tab through the bolt that connects the two. Since there's a spherical bearing in the HEIM bolt, there's nothing to keep the connecting bolt in a straignt line. So I'm guessing it was only a matter of time before the tab finally work-hardened and suffered catastrophic metal fatigue. I'm just thankful nobody was hurt as a result.

Regards,
Brian Jackson

[gyroplanes]

from what I understand about the snowbird, was it had a control end bushing that was threaded into the tube, and that they had sent a note out that they where stripping out and needed a bolt put into it. from what I heard leroy said he was going to do the mod after bensen days. to bad he did not make it home, I will never forget that sick feeling i got when i got a call that night from a pilot freind of mine at bensen days telling me of his death. leroy was a realy nice guy and he put on a great fly-in at mtn city tenn. he is still missed. and am glad our aussie freinds are still with us.

Close.
The spacer (bushing, slug) was bolted into the roll control longitudinal tube of the joystick assembly. An AN bolt threaded into the bushing "slug" after it passed through a bearing
attached by plates to the mast.

The AN bolt was the axis of roll control rotation of the longititudinal joystick tube.

The bolt was subject to rotation and should have at the very least been saftied to prevent rotation and subsequent loosening.

The "safety" to prevent loosening and failure of the roll pivot aft bolt was by providing a bolt that was too long, so long that it would stop unscrewing when it hit the mast.

I understand that the accident gyro had the wrong bolt installed. The design was changed immediately after the accident.

I was never happy with the use of the tapered pivots on the Ken Brock joystick. There was only a jamb nut to prevent rotation and loosening of the pivots. A loose jamb nut would allow the same scenario as with LeRoy's accident. Unfortunately, with the KB joystick you have twice as many opportunities for that failure mode.

I drilled and safety wired mine.

Dean,
Don't be too quick to judge Bill Parson's joystick as the cause of his fatal crash.

[Aussie_Paul]

I am a little annoyed with myself for not realising that the tube had been cut that dangerous way. Any way, I have learn't something and not died so I can't complain too much.

Aussie Paul.:)

[Aussie_Paul]

Tom, wasn't Bills problem hangtest related, or have I forgotten?

Aussie Paul. :)

[automan1223]

One of the reasons it took so long for me to get in the air was that I had rebuilt my entire control system until I WAS HAPPY WITH IT. The little'st thing I just did not want to put my life in a control system that did not feel up to snuff.

Aussie Paul, you are very lucky !!!

Anything that looks like that should be grounded. You could make that out of the strongest metals and it would still fail.

The late bill parsons died from inpatience. Instead of having ernie make him a new control stick he bent the aluminum control stick tubing in a VISE to move its position. The stick broke in flight. aluminum is not a metal I would use in a bending type stress environment like on a control stick.

I did not know that about Anthony Spagnoletti's accident. I thought he was doing aerobatic maneuevers.....

accidents like that are just too sad.

Jonathan.

[MGman]

It would seem to me that this near accident is another good reason for considering doing a total rebuild when one purchases a used gyro. Unless you know the gyro builder and know the complete history of the machine and it's build and maintenance record, I would be extremely reluctant to attempt to fly a used gyro without a complete rebuild. Unfortunately, this will greatly increase the cost of putting the used gyro back in the air, and could probably make the cost of a new gyro (kit or completed new gyro) turn out to be more reasonable than buying a used one.

Just a thought = Something to consider when buying a used machine.

Dave

[automan1223]

I am not happy with most of the designs and the materials used on the current production line of gyros.

There was a ton of hashing about rotors, and I think just as much attention should be given to the control systems.

The only design that I think deserves recognition is the design that Sport Copter uses.

However any thing can fail at any time for any reason.

[Udi]

It would seem to me that this near accident is another good reason for considering doing a total rebuild when one purchases a used gyro. Unless you know the gyro builder and know the complete history of the machine and it's build and maintenance record, I would be extremely reluctant to attempt to fly a used gyro without a complete rebuild. Unfortunately, this will greatly increase the cost of putting the used gyro back in the air, and could probably make the cost of a new gyro (kit or completed new gyro) turn out to be more reasonable than buying a used one.

Just a thought = Something to consider when buying a used machine.

Dave
Dave - I agree with you 100%, from personal experience.

Udi-

[_MOL_]

Dave,

What gyro type/model are you flying?
Is this stick design normal for this type?

[daveb]

Dave,

What gyro type/model are you flying?
Is this stick design normal for this type?

If you are asking this Dave the question, it was a 'custom built' gyro as most of them seem to be around here. I'm getting a new, proven, stick assembly made.

As to the points made about rebuilding. A new, non engineering gyro pilot is between a rock and a hard place. Not the smarts to build one, and advice generally seems to get a proven, reasonably priced second hand machine. Then learn what you can, find out what you like and go from there.

I did this yet still nearly got caught with a fault many experienced eyes missed. Obvious now. Lets not mention the engine that had to be replaced or a crook rudder cable that was spotted in time... and a string of other problems that is giving a 'crash course' in maintenance. Possibly a good thing. :rolleyes:

If I was advising myself now, the word would be to consider replacing or having experts recondition from rotors to stick inclusive. Other bits failing is probably survivable.

Here's the rudder cable that was found on the same machine a while ago. It hid under the guide which helped cause the issue. Problem was it was too thin to begin with. Maybe it was a heads up on what was to come.

Dave

[EI-GYRO]

Am I alone in thinking that the pushrod control arrangement on
most gyros is a lousy piece of design.
Lots of single points of failure, no redundancy, destabilising bias
in most failure scenarios, inadequate strength if operating off rough
strips.
I looked at a Dingbat/Wombat (not sure which) recently, and it uses teleflex
cables, one of which controls pitch, the other roll.
It seems to me that splitting the axes has some advantages.
1. Two failure modes, break or jam.
2. You lose one axis only.
3. In a properly trimmed machine, flight should be able to
continue, and a reasonable degree of control maintained.

Even a pushrod arrangement that split the axes would seem
better than the three-legged stool setup most machines use.

Paul, Would you expect to have survived this breakage if it happened at altitude,
or even 100 feet up.
Secondly, would you expect to retain control if you lost one axis only.

We all know structural failure is rare on a gyro, but pushrods and rod-ends
seem to be a weakness.

FWIW, I have the usual pushrod fit on my machine.
It's there in case my overhead stick falls off. ;)

[Doug Riley]

The differential system has its good and bad points. True, it has zero redundancy. The failure of any one piece shoots down the whole system in both axes.

It does, however, work around the principal weakness of pushrod systems in general: the fact that slender rods have lousy compressive strength. The typical length, diameter, wall and material of a gyro pushrod yield a compressive strength of 200 lb, give or take a dozen. This is a small fraction of the strength of the rod end bearings, cross bolts and other items in the load path (a couple thousand lb. or more). It's also a small fraction of the strength of the SAME rod placed in tension. By using the rods in tandem, in the worst case (stick forward), we at least have TWO of them in compression. They share the load in all other control motions, too. This design choice looks like a maximization of strength for a given weight, parts count and cost.

To get the same strength in a one-rod-per-axis setup, you'd have to go to larger tubes and/or use idler arms ("scissors") at the halfway point. The latter setup is much stiffer with the same dia. tubing, but it adds more parts, the failure of any one of which costs you control in at least one axis.

Either choice is rational if properly designed. The way most gyronauts pile weight on their machines will-nilly, saving a few ounces in the control system doesn't make a noticeable difference.

P.S.: Teleflex cables should be used with caution. They have some unique failure modes of their own, as Quicksilver drivers have long known. In the climate where I fly, moisture can accumulate inside the housing and freeze when you get up into colder air, jamming the controls. It's happened. Jamming of the rigid pieces at each end of the cable is possible as well. I believe that Ron Herron used a true redundant system when he employed Teleflexes in his 2-place Little Wing gyro -- 2 per axis.

[Aussie_Paul]

Paul, Would you expect to have survived this breakage if it happened at altitude, or even 100 feet up.

No!!!!!!! I was dead!!!!Whether it be 20' or 1000' :eek:

I agree that pitch and roll should be seperate. That way one would have some chance of recovery. Having a stable machine to start with is the sensible thing to do!!!! :D

Aussie Paul. :)

[MGman]

Brian - Actually I am not a flyer, yet. My comments come from my career experience in facility maintenance management, and 30 years of doing my own (hobby) work on automobiles, including my MG (truly a maintenance challenge). I have found that on old cars, as with what I would assume to be true for used Gyros, one must go to the basics and first make sure the safety systems work perfectly (brakes, suspension, steering) before working on improvements such as new paint, seats, and other appearance items. A nice looking car doesn't do you any good if you are dead because you didn't pay attention to safety.

I have always been interested in flying, but didn't have the time (and not yet the money) to look into it until this year, after retirement. I stumbled across Gyros (and this forum) early this year, and managed to get my first Gyro ride in February - what a blast!! I was hooked. After reading this forum, I was at elated to find a flying mode that allowed "true flying" where one could fly at slower speeds with little structure around you to block your view - what a way to really enjoy flying. I especially enjoy Stan Foster's (and others) threads with his poetic postings and the glorious pictures he and others add to their posts. This is truly the only way to fly.

I wish I were a Gyro flyer - but until then - I'll just be posting what makes sense to me as a non-flyer, and try not to get in the way of those who are much more knowledgable than I about the hobby.

Dave

[GyroRon]

I am still wanting to make and install a short but reachable overhead stick for my dominator.

I know some folks here think that I wouldn't be able to control it since everything is backwards with a overhead, and some others feel that with a good control system a overhead is simply not needed. BUT....

I feel that with some practice a machine that is stable like the Dominator, I could learn to control it with the overhead, and I also feel that having some redundancy in the control system makes good sence.

A typical fixed wing airplane can be flown with rudder and elevator trim only and be very controlable. So as long as the failure in the control system doesn't jam the flight surfaces in a bad position. I don't believe a gyro is going to be very controlable with just a trim spring and rudder. But being able to reach up above your head and reaching a short bar coming off the front of the rotorhead would allow you full control so as long as you can remember to reverse your inputs for the results you want - Push forwards to go up, Push left to go right .... etc.... -

[Harry_S.]

I had the redundant overhead handle installed on one of my Bensen's, years ago. I never had an occasion to depend on it, thankfully.

I did practice with it of course, at altitude and a couple times I did approaches to an ugly but uneventful landing.

I ran the tube handle fwd with an immediate curve down and slightly rearward and ended maybe 2-3 in. above my helmet. Put a bicycle handlebar grip on it and it didn't look bad at all. I had the hollow torque tube then and the handle fit inside just right.

I added this edit: The force needed to control with this overhead addition was quite heavy...no where near the ease of the joystick.


Cheers :)

[daveb]

Just a bit of a postscript on the control failure. I had a good friend of mine who is a 'proper' engineer cast his eyes over the gyro and in particular the broken bit. We also discussed what else to do to reasonably ensure safety. Guess this is where I should have started. :o

Close examination shows that the failed section was almost certainly cut with a grinding tool crossways. There is a slight lip on one side, faint grinding marks as well as a few deep notches consistent with a grinder operated by hand. All drilled holes in the part appear out of round with very rough edges.

The inspecting engineer thinks that it is extremely likely that there was no temperature control during the manufacture and that the 4130 chrome moly was embrittled as it became very hot. I note that the broken section is coarse and grainy, almost crystalline in appearance. This is very clear under magnification.

So we have reduced strength, add grinding marks ‘across’ the weakest area rather than ‘lengthways’ for a break to develop. Although hard to see in the close up, it appears that a 5mm crack developed on the right hand side running inboard and then it finally let go. The crack was hidden by paint.

From this analysis, the opinion is that the part was poorly manufactured and that this was the cause of the failure. Add on many hours of service and significant shake in the system. It was just a matter of ‘when’.

There are a couple of shots of the rest of this part. The other end appears to be manufactured in the same manner. You can clearly see a sizeable notch and it looks a little thin around the edges. I was told there were better ways to design this part and the one that broke.

Dave

[mceagle]

As Doug said, in the common differential system, a failure of one part and the whole system is shot down in both axis. The same is true even if you separate pitch from roll.
A push rod system can have redundancy built in but you need to utilise 3 pushrods (something like the controls on a swashplate).

[Vance]

Ron Heron had three tubes on his little wing and won an award at Mentone two years ago. It seemed cleaver to me. This failyer looks like a poor design that was poorly exicuted, but I have seen worse. Thank you, Vance

[birdy]

Ron A,mate,have you tryed fly'n your machine useing the rods??[reaching behind the seat and controling the head from the rods.]This is assuming you can reach the rods from the seat.
Its handy to know you can do it if the systm fails somewhere between the stick and the rods.
To account for top rod end failure,I'v had small safty wires [light SS cable]attached so if the top rodend failed,the link has'nt been compleatly severed,only more sloppy.
If you can fly/land while controling the head from the rods,with the top rodends wired,you should be able to survive a failure anywhere in the control systm.

Been think'n bout rearranging the back window on the RAF cab,so it can be punched out to allow access to the rods in an emergency.

[Brent_Brown]

Dave how many gyro fly with this type controls? what is the highest time on this type. or is it a one of a kind?

[daveb]

Dave how many gyro fly with this type controls? what is the highest time on this type. or is it a one of a kind? This particular one has over 400hrs, it was a one off but I believe the gyro's design has been copied once.

As to the control setup all I know is the following few words which I am quoting from a post on the Aussie forum "...Plans for this type of system have been floating around for a while now, I think they may have originally been sourced from the US." Even then I believe that if it was not reduced to a single tab and was carefully manufactured, it may not have failed, but I don't trust it. A complete, very well proven, professionally made setup arrived today, that old stuff is going in the bin!

Dave

[GyroRon]

I can't reach them from the seat Birdy.

[Brian Jackson]

Besides Don Shoebridge's Hornet plans and the pump-handle plans, are there any Brock-style cyclic control plans in the public domain? I've searched the net and found very little. Thanks.

Brian Jackson

[Aussie_Paul]

Birdy, in your pitch unstable htl Raf it would be all over by the time you had sent the first puch!!!!!!!!!!

I am in WA at the moment.

Aussie Paul. :)

[birdy]

In some situations Paul it wouldn't matter wot you were fly'n. But its nice to know that if you could reach back and control the head through the rods at any time.If I woz a little higher when me stick broke I wouldn't have had a problem,but as it woz,it broke at the flare,with a howling X wind.By the time I realised the stick broke,the wind had already pitched the machine over and ......................... .


Not even over your shoulder Ron???

[Aussie_Paul]

Agreed Birdy, any chance is better than no chance!!!!!!!!!!!

Aussie Paul. :)

[Dale Young]

Birdy, I have'nt shot a landing (sticks-only) yet, but see no reason why I could'nt. It only took a few moments to get completely used to flying it like that. A failure now would only be a non-event. I , like you, believe that a little sticks -only practice, from time to time, is a good safey measure.The SS wire is even a better addition!

[Doug Riley]

Birdy, I'm interested in your safety wires. There have been incidents of rod end bearings breaking or pulling out. It's rare and seems always traceable to lousy workmanship or poor installation... but that's only as far as we know.

Have you actually controlled the craft using only the wires? I thought about trying this myself, but figured the slop would be so great that it would just lead to hopeless oscillation...

[birdy]

I figure any connection between my hands and the rotor head is better than noth'n Doug.
I think you read'n me wrong tho with the wires.
It's only a SS cable loop that is setup between two tangs,one tang attatched to the bolt go'n through the rodend bearing and the other tang anchored to the threaded insert bolt in the rod.Depending on the linkage setup,there can be as little as 2" of slop in the rod if the rodend failed............wich is better n noth'n.

I'v never flown by the wires coz I'v never had an end fail......yet..............but have done plenty us'n the rods.

[Doug Riley]

Yeah, Birdy, that's what I pictured. Kind of a glorified electrical jumper.

Another way of making the rods redundant (that's been discussed on the old forum) is a 2-axis inflight trim system that works independently of the rods. Many people are going to inflight electric trim systems anyway. As gyros get heavier, the control pressures get objectionable unless you have some way to dial them out in flight.

[EI-GYRO]

Ron. the trick to using the overhead stick is to think of the rotor disk, and what you want to do with it. The control actions follow almost automatically if you think that way.

If you do install an overhead, it should be as long as possible, while remaining out
of your line of sight in normal flight, as it would distract you. A normal length
overhead stick has the same or slightly less control force required than a joystick,
but the shorter you make it, the more force will be reqd.

The third pushrod would be a the ideal solution, providing redundancy in both
axes, and eliminating the incoherent residual control after a breakage, which is the
big problem.

Question is, how do you implement that in a pusher gyro, where the engine is in the
way of where the third pushrod should go.

Answers on a postcard to.......

Cheers.

P.S. The difference between a joystick and an overhead is about the same as
operating your car steering with both hands at the bottom rather than at the top
of the steering wheel. Not a real biggie.

[RHerron]

EI-GYRO,

You said:

<<Answers on a postcard to......>>

Give me an address to send the postcard and I will draw you a schematic for the third-member system for a "pusher". Exact configuration will depend upon how your rotor brake system works.

I would like to see all gyros with this system. On my Little Wing-3 it was pretty straightforward to add the third push-pull rod. This is the system Vance mentioned seeing at Mentone.

Other configurations require a little "fiddlin'" to make it work but it still isn't too complicated and is a combination of my single-place and two-place systems.

Ron H

[birdy]

"a 2-axis inflight trim system that works independently of the rods."
I'v tryed fly'n the RAF with the trimms Doug,and it would have to be very calm air,or a steady direct head wind to be able to land like that,they are just too slow.

[Ted Eggleston]

Birdy,

What type of rigs have you flown and how would you sum them up, knowing what you know now?

Obviously in your case when you are down there at rump flight level, if you want to turn left or right, you need it now and not 6 feet after entering the branches. So any delay in responce to control input is needed to be minimums.

For the rest of the guys who either want to play hide and seek in the clouds or drift along at 500 ft, what is considered to be reasonable responce times to any control input?

Ted

[Doug Riley]

Fergus, I started with an overhead stick and sang their praises for a long time. The system doesn't SEEM "reversed" to me. I think of the cross-handle and vertical shaft as a representation of the gyro's axle and mast. Tip the "little gyro" in front of you in the direction you want the real one to go. It OUGHT to be intuitive if, as you say, you think about what the rotor is doing.

When some of the more accomplished gyronauts I knew (Chuck Beaty, John Landry, Ralph Taggart) simply couldn't get used to them even after many hours of practice, though, I began to wonder. People who first encounter the overhead stick as adults don't seem to take to it easily at all. Perhaps by the time we're grown, we've all seen too many Hollywood aviation movies where the hero pulls the stick back to head for the stars.

Whatever the reason, I've given up advocating overheads on gyros ... even though I still like mine.

[EI-GYRO]

Doug, It is probably dependant on which one you tried first.
Like you, I dont spend a lot of time trying to sell the overhead stick
to folks used to a joystick. Why would they want to learn something twice?.
But most folks acknowledge that it is mechanically simpler, and wont input
spurious control forces if it does fail.
Incidentally, I have no difficulty with the joystick on the twinnstarr, or the joystick
on my radio-controlled airplane.
Maybe it pays not to think about it too much.

Fergus.

[EI-GYRO]

Hi Ron,

My snail-mail is 15 St Patricks Park, Blanchardstown, Dublin 15, Ireland.

e-mail ; rotorhead@eircom.net.

Would appreciate this very much as we operate off grass strips and the
pushrods get a hammering.

Cheers

Fergus.

[Udi]

Ron H.,

I think your 3'rd rod designs would be of great interest to many people. I would gladly digitize and post them right here if you want to send me the schematics.

Thanks,

Udi
gyroplane(at)bigfoot.com

[Dean_Dolph]

Ron H.,

I think your 3'rd rod designs would be of great interest to many people. I would gladly digitize and post them right here if you want to send me the schematics.

Thanks,

UdiAgree! In addition this type of info should be in the PRA magazine to reach those that visit here.

[Harry_S.]

Old ingrained reflexes are VERY difficult to modify and/or change; more so in a crical situation.


Just my opinion...but I stand by it. ;)


Cheers :)

[birdy]

What type of rigs have you flown and how would you sum them up, knowing what you know now?


Rigs?????

[Aussie_Paul]

Birdy, it would be impossible to fly your pitch unstable Raf with trims!!!! :eek:

I could have landed the Magni M-16, I flew the other day, with pitch trim. ;)

I have landed Hybrid with the Raf trims when I had the most stable rotors, I have flown so far, on it!!!!!! :D

Aussie Paul. :)

[bones]

Birdy i love the quote under your signature, hmmm i've gone by that one more than once :)

[barnstorm2]

Birdy i love the quote under your signature, hmmm i've gone by that one more than once :)

me too..........

[birdy]

Paul B blurted,
"Birdy, it would be impossible to fly your pitch unstable Raf with trims!!!"
Paul ,mate,you are so full of sh*t,I'm supprised you haven't poped yet.
I have flown it with the trimms if you must know,and I'v even landed,only needing a bit of backstick to stop ,[before I ran off the road].
I woz compar'n it to the ferel,I can land that in any conditions by the rods,but the RAF,with the trim wheels, wouldn't be so easy..............in bad air.

Though I'm interested in why you reckon it'd be "impossable".

[birdy]

Hmmmm...........Thankfuly Steven,I'v never HAD to do it...............yet.

[Chris Burgess]

I also flew with Leroy. I sure liked the guy. A student of mine was there on his last flight day. Comment on Leroy's accident. More is there than was printed. I own a SnoBird Adventurer and have made several mods to fix what happened to Leroy. I have many hours in the Adventurer. It is a good trainer and does not fly itself. I can however cruise without touching the stick, by only throttle changes. Anyway, I feel the rear seat support broke first. This part actually is triangulated to the front seat for it's support. When it broke, it let this loose pivot bolt, that was too short, pull all the way out of the rear control rod pivot when the Keel flexed downward. Since that accident, the bolt now comes from inside the control tube. It is captured and can not come out. Both ends are now this way with one end floating. For the control system to come loose, parts must be unbolted to get it out. Point is, several things led to this accident, not just the stripped out bolt. I know. I've seen the cracked rear seat support. It is an intricate structural part. It was also beefed up to double the wall thickness. With these changes, this accident should never happen again. Get your blades smooth. If they aren't, you have some more work to do. Two blade systems will have some shake, but you can get most of it out if you work at it. In straight and level cruise flight, there should be essentially no load on the control rods.

[Aussie_Paul]

....Paul ,mate,you are so full of sh*t,I'm supprised you haven't poped yet.

Birdy, at least I get rid of mine down the dunny (Oz toilet), :p you put yours on the forums!!!! LOL ;)

Ausasie Paul. :)

[birdy]

Don't say much for you then ay Paul,your stupid enough to keep read'n it.

[REDHORSE556CES]

.....to be able to sit down and have an evening meal yesterday!!!!!!!!!!! :eek:

I had flown 3 circuits in Daves gyro adjusting the trim spring, as well as checking the shake after Rosco had blue printed the head.

We had also moved the tail feathers back 18", so these flights were part of a testing procedure. While the head was at Roscos, we fitted an original Bensen head that I had availible. The extra trim spring requirements took me by surprise :eek: until I realised that the torque tube offset was 1" instead of the usual 5/8" that is commonly used in Oz.

Both Dave and I flew the Bensen head with the DW blades.

When I was happy with the trim spring location I told Dave to go for a fly to see what he thought, as he had flown the most hours in this machine. I felt that the shake had not improved much, if any, but the pitch stability was much improved.

When Dave came back after a little over an hour, I discussed with him what he thought. Dave was still unhappy, as I was, with the shake but commented that the pitch stability was certainly improved.

I suggested that we remove the pre rotator, as we had proven the week before the head had been sent to Rosco, that the shake was less with the pre rotator removed.

I also suggested that maybe the undersling should be looked at as the DW blades had a few holes to try. Also there had been comments on the forums regarding BW bldes being a little sensitive to undersling. We decided to change the teeter hole and Dave did that as well as removing the nylon blocks to allow enough teeter.

I taxied out and started the take off roll. I was gentle with these "bastard" :eek: DW blades, and soon they were ready to lift the nose. As the nose lifted I moved the stick forward and thought that it move a little too easily. I kept applying power and the machine started to roll to the left just prior to lift off. I applied right stick and nothing much happend, so I immediately reduced power and let things, and myself, settle down!!!!!!!!

I was surprised with what I head felt!!! I increased speed again and did not let things progress quite as far. The machine seemed so different!!! :eek: I could not believe that a change of the undersling height of 3/4" would be affecting the machine this way.

I taxied back feeling the machine as I went. With the stick full back the roll was normal, as I pushed the stick forward I seemed to lose roll control!!!!!! As I turned to line up I decided to undo my seat belt and have a look. As I moved the stick, the head did not move accordingly!!!!!!!!! :eek:

I taxied back to the hanger and shut everything down, and said, "the control system felt funny"!!!!! :mad: Ater getting out and having a look at the broken bit I sat down and realised that I was correct in my "feeling". I was so glad that I did not "just get it into the air" and sort it out as most of us experienced test pilots do!!!!

When I realised that I had flown with an enourmous amount of backstick pressure, due to insufficient trim spring pressure, and that Dave had flown for an hour just prior, I realised that today was not our day to meet our maker!!!!! :eek: I won't say f**k again, I promise!!!! :eek:

I did sit down for a moment!!!!!!!!! and then relised that second hand machines can, and have been flown by people who may not have had any idea of the mechanical strains that occur. The previous owner obviously had no idea re mechanical things and as such was about to die if he had not sold the machine!!!!!!!!!

Luckily for both Dave and myself, I was able to appreciate what was happening and we did not end up with a wrecked gyro or human damage, especially me!!!! Sorry Dave!!!!! :D
This area of the gyro was painted and could have hidden a crack. Far to many gyros for sale have paint slapped over everything before sale!!!!!!

Aussie Paul. :)
Slapping a coat of paint on it eh? Around here we call that a "Sherwin-Williams Overhaul".