Could anyone help me with a material strenght calculation of this operating horn from crashed plane? 10

[RedSnake]

Picture elevator to the left and stabilizer to the right.

The red cirkel is a tourque tube on the rudder and have a diameter of 38 mm and the thickness is 1 mm.
The operating horn was a welded box design using steel sheet AISI 4130 in condition N thickness is 1 mm welded against the tourque tube.
On the uperside and sides (3/4 of the circumference) has 30% of the normal materiels strenght(severe lack of fusion).
The last 1/4 can be brittle or have been sheared.
The red triangle is the mechanical stop maximum up.
The relationship between hinge, tourquetube and elevetor edge ca..
0 --------1 --------------------7
Can this construction hold for 5,7 G ???


[img [URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1604784211/tips/STABH2_lpxbcz.jpg[/URL]


Properties Metric Imperial
Tensile strength, ultimate 560 MPa 81200 psi
Tensile strength, yield 460 MPa 66700 psi
Modulus of elasticity 190-210 GPa 27557-30458 ksi
Bulk modulus (Typical for steel) 140 GPa 20300 ksi
Shear modulus (Typical for steel) 80 GPa 11600 ksi
Poissons ratio 0.27-0.30 0.27-0.30

 

[Alistair_Heaton]

Btw what's daN

The control gearing is X5 so don't divided.

Not that it makes much difference. That control load is more than a bit optimistic in this situation. A young guy will easily pull or press 50 kg X that by 1.5 when adrenaline kicks in. 35 kg is the book figure you are correct. And will be what the design cord will presume. It's not realistic though.

 

[RedSnake]

1 deca Newton 1 daN =10 N = (1kg)'
Something old people use ;-) Have only seen it in old machins in the factory.

/A

 

[Alistair_Heaton]

Ok thanks

 

[RedSnake]

As said, the left stabilizer was broken off last, so it is not really significant, but on the right side, the bolt was okay.

About the min max stop.

The elevator movement is limited by adjustable stop screw heads for both LH and RH
side. These stop screws meet the elevator horn. Examination of this screw heads confirm severe hammering on the top side. The RH side stop screw show more extensive
damages compared to the LH side, see Figure 38 and 39.
The wear damages on the stop screws an increased extent on the RH side.

Left side

 

[Alistair_Heaton]

Not surprised if they haven't been using gust locks. As in the bungie pic I posted earlier.

It's a function of being in a hanger or sitting on the ramp.

It's the owners policy what happens about restraint of controls if it's left outside.

Some chief pilots it's a sackable offence to leave the plane so the controls can move. Others it's not.

You have to remember in the clubs the object is to jump not fly. They will have multiple best practise rules dealing with parachutes. The aircraft is just tractor. And a pilot saying I will only take 7 instead of 8 is unemployed

This where gliding clubs are safer and more controlled because gliders are just an unpower aircraft and you most certainly wouldn't do that sort of thing with a glider

 

[RedSnake]

CP said the plane was like a Volvo 245 LOL the only car I had the last 25 years
I will ask him about this.
I don't remeber everything that has been said, have mostly
talked to him on the phone.
I have filled all the memory space in my brain with too many aircraft facts so I do not remember all the discussions.

Did you get all the firewood in?
I do not know if you are a night owl
But maybe it's time for bed?
Thanks for today, and sleep tight.

 

[Alistair_Heaton]

 

[Alistair_Heaton]

Brother in law round had sauna and it's Friday no flying for week...

CP sounds like a parachutist not a pilot. The auld boy at edzell when asked about parachutist perversion would just answer why the hell would I want to get out of a perfectly serviceable aircraft.

Just remember the CP is liable for all operation procedures and practices. He might be telling yo the whole picture because he knows very well he might have a trip to court about what he has said.

The crash in Inverness I have just passed on the advice to record and document every interaction with anyone to the person's partner. Its looking like a main rotar detachment which is mostly likely maint. But there is kids involved.

 

[RedSnake]

Yes its true he is also a god friend to my partners brother, I know he didn't say musch the first month or so. But then again he was co pilot the first jump with the pilot that crasched then he was jumping the second with the same pilot and at the third it crashed, so I can understand if he was in chock then.

That is more then 20 times more timber than I have in my summer house
Yes he is both, he and my parter took there jumping liecenses at the same time he was the one who asked if he wanted to come along. When we where going in school. But he have flown more than jumped.
Some things you can't ask him, I think he flies on muscle memory, so he can't explain it.


I'm more into growing things, it's so different from what I do at work I do not have to think so much then.

 

[Alistair_Heaton]

All of us do, it's when you don't have those muscle memory reaction that's dangerous. But there is only one way to get them.

I have problems on the 737 thread explaining the communication and the utter shock of the machine playing with the controls.

The wood is to burn in this

 

[RedSnake]

Bake oven! nice
It's nice with fire I like it.
Does not seem to be able to type properly will not find the keys.
Now it's off to bed, It was nice talking to you.

Best regards Anna and sleep tight

 

[Alistair_Heaton]

Night just ask what ever you like about the aviation side of things I will try and answer if I can. If I can't I will say. The real engineers in the forum will deal with the engineering.

I have never heard of one of those arms fail.. push rods yes usually fatigue and only one bolt and it was a out of spec material issue. No fatalities with any of them.

To note 2 flights training then dropping solo.... Err no chance if I was cp

 

[waross]

Respectfully, Alistair, there is another way.

Btw I reckon Anna should be allowed to post what ever she like question wise.

Questions should be posted in an appropriate forum.
Posting in the wrong forum is contrary to the posting guidelines and tends to upset some members.

If she feels comfortable doing it with us.

Yes, I understand that.
A solution is to post the mechanical question in an appropriate forum and then post a link in this forum requesting that folks look at the linked forum.
Posted in one of the mechanical fora, the question may be presented to a larger group of experts in the field.
A link in this forum will lead the group following this thread to the other question.
I have posted your question in the Mechanical Seal Forum.
Here is the link:
thread819-476070

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[RedSnake]

I apologize, I have not been in any forum in 20 years so I am a bit of a beginner, have not really had time to learn all the rules. But if I am honest I did not check the rules either.
I was a little frustrated when I started this thread. Just wanted answers to all my questions.

I have posted your question in the Mechanical Seal Forum.

Okay thanks!
The reason I asked was that I was given the task of setting up preventive maintenance for all personal safety points on our hydraulic presses based on all machine and work environment laws and in the supplier's safety test protocol it only said General: Gland bolts? So it was just a quick question because I did not know what they looked like or what it was. I'm primarily an electrician, not a hydraulic or mechanic, even though I read that too, our hydraulics or mechanics did not know what was meant either. Had not intended to start a long discussion about them.

Sorry.

To note 2 flights training then dropping solo.... Err no chance if I was cp

He had a bit more than 200 hours and total 25 lifts and 6 alone. But of course if it takes 10,000 repetitions of someone to become a professional, it is far from it.

I have to correct that, it is 18 with co pilot and he went to flight school in Arvidsjaur.

Best regards Anna

 

[Alistair_Heaton]

Sorry Bill I must admit in my wine soaked state I thought it was an aircraft part. They are used quite extensively for going through fire bulkheads with control runs or electrical on unpressurized aircraft and through pressure bulkhead's on bigger stuff.

19 supervised training flights isn't too bad to be honest. I only had one flight more than that going onto my latest type. 40 flights after that I was fully released for low vis operations. But that's multi crew and the low experienced on type are kept apart for a period.

I went off to be an instructor which was always my plan when I got my CPL and was in a similar experience state. You learned a lot very quickly about handling both demonstrating and recovering from students. Plus also there is a section of the instructors course which deals with recovery. At the 1000 hours point when I went to fly bigger things and was asked to do para dropping I was a completely different pilot to the pervious year. Which is another issue these jobs are seen as stepping stone jobs so just as a pilot becomes useful they disappear off to do something else.

 

[LittleInch]

Just wanted answers to all my questions.

I'm quite conscious this thread has diverged quite a bit from your basic question, but have we helped you in this?

Assume CP is Chief Pilot?

TBH, the best jump pilots I ever flew with were also skydivers and hence they really understood what we were looking for and how to get us to the run in at the top of the climb and in the right direction.

I'm sure the chief Pilot is also suffering in his own way and must have some reservations about what happened and how he can make it not happen again.

Skydiving centres often operate on a shoe string and in general lifts to altitude are break even at best, so one less person makes a big dent as people could just frequent another location where it's 15% cheaper per lift. The places stay afloat due to first time jumpers either static line, AFF freefall or many many tandem jumpers.

A volvo 245 eh? That looks about right - it is certainly a very basic, boxy aircraft alright.

Actually the worst car I ever owned was that colour as well - complete death trap that nearly killed me when the suspension arm came away from the chassis as I braked hard...

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[RedSnake]

I'm quite conscious this thread has diverged quite a bit from your basic question, but have we helped you in this?

Almost an answer anyway. No criticism of anyone here.
I might have gotten an answer sooner if I had presented it in a different way.
Just like beams and hinges with stops and weights and never mentioned the word airplane .....
But it has helped on a more personal level just to be able to talk to someone about it and discuss it.
At first I could not because it was confidential and then came Corona. I've hardly talked to anyone in a year and a half.
And I have no one I know who is at such a level technically when it comes to mechanics and flight and stuff that it has been possible to talk about it.
In other words, it's been nice talking to you.
Although we do not always have the same approach to the problem.

Assume CP is Chief Pilot?

Yes

Skydiving centres often operate on a shoe string...

Here in northern Sweden, there is a long way between the places where it is possible to jump.
So it is only in the summers vaccion that they have the time to go to jumping camps and so on,
then they often bring there own plane if it is possible and it is not on service.

In Sweden, the parachute clubs are associations, which consist of the people who are members.
They need nothing more than to make it go around.
Of course, it is better for the members if others are involved and contribute as you mentioned to reduce costs.
In this case, I believe with emphasis on believe that the plane was owned by a company affiliated with the parachute club association, it is probably more a matter of taxes and deductions than anything else.
From SHKs report: The fact that the person responsible for the flight operations within Umeå Parachute Club accompanied as a jumper on the second flight of the day indicates that there were no question marks about the pilot's assessed ability to carry out the flight under the conditions that existed then.

My partner was a AFF instructor ..
Today 1 year and 4 months since the accident.
I miss him...

A volvo 245 eh? That looks about right - it is certainly a very basic, boxy aircraft alright.

That is exactly the coulor of my last 245, gold metalic
In Sweden they are called tractors, they are impossible to wear out and can withstand allmost anything, not sporty!
More like a trusted old workhorse.
My current one was made in 1989 and is red.
Girls like red cars best ;-)

Summation as far.

Left elevator:
Push rod bent 23 degrees.
Eyebolt fractured.
Severe hammering on Min stopp screw head.
Horn/lever broken but not completely off.

Right elevator:
Push rod Okay.
Eyebolt Okay.
No one mentioning of any injuries to any of them.
Even more severe hammering on Min stopp screw head.
Horn/lever broken off.

From metal report.
According to Gippsland Aeronautic Manual (p51-2) all welded steel tube structure is
deemed to be primary structure. The welding acceptance criteria for this part are however
not known.

Go for weakest link which is that bolt that goes thought the U bracket on the end of the arm. ..

Did I understand you correctly if you meant that the weakest link "should be" the eyebolt at the end of the push rod?
Or do you mean that it is the part that is most often exposed to fatigue errors?

Warm Greetings Anna

 

[RedSnake]

Two questions I probably have more but start with these two.

1. You practice stalling with the plane. Halfway through the recovery, you drop the right elevator.
What happens to the plane?
How do you solve the problem?

2. You make a turn, bank/ angle of 60 degrees. Halfway through the turn, you drop the right elevator.
What happens to the plane?
How do you solve the problem?

The elevators are 2 separate parts and are controlled by 2 separate push rods that are controlled via a walking beem and then via wires. Completely mechanical no hydraulics.

So if the elevator lever/horn brakes of the elevator on one side it can no longer affect the lifting force. It accounts for about 3-4 percent of the lifting surface.
Imagine that you remove the right elevator and throw it away and then you try to fly the plane.

Best regards Anna

 

[LittleInch]

Anna,

The elevators work as a pair. Instead of "drop the right elevator" do you mean "the right elevator control breaks??"

No 1 I think I asked that question earlier and I don't think there is an answer.
No 2 A banked turn should have the elevators pretty neutral I think. Also do you mean a turn of 60 degrees flat or a bank/ angle of 60 degrees (fairly brutal in a plane like that).

A missive unknown here is how it breaks - suddenly or gradually or does it jam it in one position? I think there was an aircrash of a plane where the rudder went full direction and basically you couldn't control the aircraft due to the degree of sudden movement of a powerful part of the aircraft.

https://en.wikipedia.org/wiki/Boeing_737_rudder_issues

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[RedSnake]

bank/ angle of 60 degrees (fairly brutal in a plane like that).

It's example. It's not related to the accident. I am just trying to get a grip on how things work.

Best Regards Anna