Suitable Materials for use in Modifying Experimental Airplanes

Homebuilt Aircraft & Kit Plane Forum

Help Support Homebuilt Aircraft & Kit Plane Forum:

wktaylor

Well-Known Member
Joined
Sep 5, 2003
Messages
347
Location
Midwest USA
OK guys.. for giggles... RE your aluminum angles from 'Lowes or Home Depot airplane departments'.

What is the fillet radius between the angle flanges?

What was the alloy 'as-mill-marked' on the aluminum?

Where were they made [extruded]?

NOTE. A year-or-two ago I needed a mild detergent for cleaning rubber parts. Called the 800 number on the Dawn dish-soap bottle to ask simple questions.

As soon as I mentioned what I wanted to clean old/dirty nitrile rubber parts... the first question asked by the help desk guy was "for what application"?

"For cleaning rubber clamp blocks in aircraft hydraulic tube routings".

"OK, STOP there... I can't discuss our product use in any aircraft application".

What do you think Lowe's and Home Depot's reaction would be if You inquired about their 'airplane [parts/materials] department(s)'? It would be educational to hear what they have to say...
 

proppastie

Well-Known Member
Log Member
Joined
Feb 19, 2012
Messages
5,228
Location
NJ
I was able to interface with the manufacturer of the angle I found at Lowes and they said it was 6063 as previously discussed by Marc Z.
 

12notes

Well-Known Member
Lifetime Supporter
Log Member
Joined
Aug 27, 2014
Messages
1,235
Location
Louisville, KY
What is the fillet radius between the angle flanges?
For Aircraft Spruce's 6063 angle they have this note:
"No Radius; this listed product has a sharp corner inside and out " So Home Depot's can't be any worse.

What was the alloy 'as-mill-marked' on the aluminum?
Last time I bought it, yes, but I think it was Lowe's.

FYI my plane has used both AS&S and Lowe's 6063, I can't tell which is which in appearance or markings.

Where were they made [extruded]?
Who cares? Either you believe the manufacturers or you don't. There is no reason to believe Aircraft Spruce's manufacturer over Home Depot's. Manufacturing test results are worthless if you believe manufacturers are lying. A manufacturer stands to lose a lot more by lying about the quality to Home Depot than lying to Aircraft Spruce on volume alone. We have zero control over either.
 

Marc Zeitlin

Exalted Grand Poobah
Joined
Dec 11, 2015
Messages
998
Location
Tehachapi, CA
OK guys.. for giggles... RE your aluminum angles from 'Lowes or Home Depot airplane departments'.
WK, I'm flummoxed by your concern regarding the fact that I used aluminum angles from Home Depot for a non-structural component in my airplane (and in some of my customer's airplanes). As I clearly stated, in this case (and what I recommended to Bill) was using it for stiffeners to assist the IP in staying rigid, and in holding the instruments in place. Nowhere have I ever recommended using random bits of metal (or anything else) that the aircraft designer didn't approve as a major structural component.

What is the fillet radius between the angle flanges?
epsilon, just like the ACS angle.
What was the alloy 'as-mill-marked' on the aluminum?
Nope. Just a sticker with a bar code.
Where were they made [extruded]?
Not a freaking clue. No clue about the ACS angle, either. I suppose I could find out from Jim Irwin, if I bugged him or his support staff enough, but to what purpose?
What do you think Lowe's and Home Depot's reaction would be if You inquired about their 'airplane [parts/materials] department(s)'? It would be educational to hear what they have to say...
Me - "Excuse me - can you tell me where your aircraft parts department is - which aisle"?​
HD - "Huh? We don't have an aircraft parts department"​
Me - "OK - can you tell me where you keep your aluminum angle which I want to use to stiffen some bracketry for my aircraft instrument panel?"​
HD - "Oh - sure - aisle 8"​
Me - "And your tie-wraps / zip-ties?"​
HD - "That would be aisle 3"​
Me - "thanks a bunch"​

Pretty much like that. I guarantee you that none of the folks working the floor at HD give a FF for what I'm using AL angle, tie-wraps, 1x2's, spray foam, sheet metal screws, or any other thing.

These brackets (in this case) are running just about a safety factor of just about 100, from a strength standpoint. If they cracked, I'd find the crack on the next CI. If they cracked and broke off on one end, the IP would be slightly more flexible, and when someone pushed a button really hard, they'd notice the IP move 1/8" more than it otherwise would. And if I pulled 3.8G (the maximum allowed for the COZY MKIV) with a broken bracket, beside me blacking out, the instruments would move 1/4" downward at the front end, and the IP would bow a little bit.

If you're at all familiar with System Safety Analysis / FMEA, and if this were a system, and not a structure which isn't analyzed using SSA/FMEA techniques, whatever failures would be associated with this bracket would be either "No Effect" or "Minor" (Development Assurance Level "E" or "D").

So if I were you, I'd really let this one go - I have no idea which hill you would like to die on, but I really don't think it's this one.
 

proppastie

Well-Known Member
Log Member
Joined
Feb 19, 2012
Messages
5,228
Location
NJ
its a tough crowd ........would hate to try to do standup comedy here.......
 

wktaylor

Well-Known Member
Joined
Sep 5, 2003
Messages
347
Location
Midwest USA
Some Fud-4-Thot... then I'll shut-up and go-away for good.

1. Were the extrusions actually made in USA and to what ASTM or MIL or 'whatever' spec?

2. What other materials or parts do YOU use [or recommend for use] from 'Lowes or Home Depot airplane department'?

3. Call Lowes or Home Depot service hotline and ask about using their stuff in Acft.

4. Relevant thoughts by sm'others...

"You deserve to get what you ask for: but if You don’t ask for very much, don’t expect to get very much.” -- 'old/experienced' Xxxxxx parts engineer

Alternate versions, by others…

"You don't get what you want... You get what you ask for. Ask carefully!” –TheTick, Eng-Tips

"You may not get what you asked for... but [for sure!] you never get more than you ask for!” –EdStainless, Eng-Tips

Bye.
 

dwalker

Well-Known Member
Joined
Mar 6, 2021
Messages
362
Location
Tennessee
The one thing that we can use a lot less of in this world is FUD!
Fear
Uncertainty
Doubt

If you are one of those people who tend to spread FUD than maybe think before you speak or just keep it to yourself.
FUD often gets in the way of ACTUAL important and potentially dangerous information getting through or effectively communicated, which places people in actual harms way.
Less FUD, not more!
 

rv7charlie

Well-Known Member
Joined
Nov 17, 2014
Messages
1,872
Location
Pocahontas MS
Hmmm...Sounds like you're spreading FUD, and then telling us to avoid it. (?)
I haven't carefully perused a set of Pietenpol plans, but I suspect that you can build the entire airframe from stuff available at the local big box store (though I'd personally prefer to use AN hardware). I'm *certain* that the prototype and all the early copies were built without *any* milspec parts. Is there a milspec for a Ford Model A engine? You can even build the wing spar for an unlimited acro a/c like a One Design with wood sourced from an accommodating local lumber yard (it's in the plans set). You just have to know how to select wood for correct properties.

There's FUD, and then there's rational, informed decision making when choosing materials & uses.
 

12notes

Well-Known Member
Lifetime Supporter
Log Member
Joined
Aug 27, 2014
Messages
1,235
Location
Louisville, KY
Some Fud-4-Thot... then I'll shut-up and go-away for good.

1. Were the extrusions actually made in USA and to what ASTM or MIL or 'whatever' spec?

2. What other materials or parts do YOU use [or recommend for use] from 'Lowes or Home Depot airplane department'?

3. Call Lowes or Home Depot service hotline and ask about using their stuff in Acft.

4. Relevant thoughts by sm'others...

"You deserve to get what you ask for: but if You don’t ask for very much, don’t expect to get very much.” -- 'old/experienced' Xxxxxx parts engineer

Alternate versions, by others…

"You don't get what you want... You get what you ask for. Ask carefully!” –TheTick, Eng-Tips

"You may not get what you asked for... but [for sure!] you never get more than you ask for!” –EdStainless, Eng-Tips

Bye.
All those questions have been answered, you're just rephrasing them without making any new valid points.
 

wktaylor

Well-Known Member
Joined
Sep 5, 2003
Messages
347
Location
Midwest USA
OK, guys, I think I need to expand on my concern with '...circles and arrows and a paragraph on the back'. Sorry if this 'read' is too-long...then... don't-read-it... TLDNR.

I have been 'active' in aviation since my dad started building his T18 in 1967 and when I soloed in 1968. THEN In 1974 I had an eye-opening safety incident at OSH while taking a ride in a highly altered T18... that came close to claiming my life [have I discussed this in a prior thread?]. I have been a working aero engineer, including mishap/accident investigator for/supporting general aviation/homebuilts... and the military... since April 1979. I am now the old guy I used to seek out. Enough of 'I'.

Certified aviation-grade parts/materials come with a price... but also [should] come with performance and confidence in their heritage. Non-aviation parts and materials are always wild cards... based on 'trust-me-its-OK'.

The case of a 'simple extruded angle', without mill-markings, at the center of our discussion is a classic case of judicious but 'inappropriate trust'. In truth, a carefully formed/bent angle made from [mill-marked] 6061-T4 or 2024-T3 sheet, same thickness, would be as strong and stiff as the unknown extruded aluminum angle from L/HD, same thickness, with no fillet radius... and the aviation heritage of YOUR bent angles would be unquestioned... and just as functional.

Note to MZ... with your credentials... You are obviously aware that human factors is a HUGE element for basic safety... personal and societal. Decisions made often have 'wicked-irreversible' consequences. Using non-aircraft parts and materials from 'Lowes or Home Depot [L/HD] airplane departments' can make sense if chosen/used wisely... but this wisdom takes time to learn... and it must be documented... and it must never become flippant or common. Unfortunately what should be a rare occurrence often becomes the go-to-expedient... second nature... why-bother-asking???

There will be people in this website who will see 'L/HD airplane department' as a way to save a bunch of buck$ without knowing the corresponding issues/risks, like YOU and I, DO.

YOU obviously have the skills/ability to judiciously choose materials... when even good A&P licensed and military mechanics simply make mistakes in judgement... after-all what really is the difference between a piece of sheet metal: L/HD-aluminum or 6061-O, -T4, -T42, -T6, -T62 and 2024-O, -T3, -T36, -T42, -T62, -T81 or 7075-O, -T6, -T62, -T73, -T76... bare and clad and industrial and aviation specification grades? Since YOU truly understand these differences, ATTABOY! All others should be very cautious... and ask... even with instrument panels.

Anything You can touch/grab/lean-on/fall-on inadvertently ARE subject to 'abuse loads'. Also, aluminum sheet/plate panels are also used as common 'electrical ground paths'... each of these metals/tempers has unique conductivity and long-term corrosion-potential at contact points.

AC43-18 FABRICATION OF AIRCRAFT PARTS BY MAINTENANCE PERSONNEL was written because of this very worriesome problem.... and is the essence of what has taken me ~40-years to grasp as second nature. I have wintessed 'good intentioned' mechanics... and fellow engineers... take unbelievable shortcuts and have brain farts... ALL...THE...TIME... without a clue... as to 'why' something 'had-to-be done by-a-book they've never read'.

My grandpa had his own roofing business in SoCAL from the early 1930s to late 1950s. He had lots of unique 'favorite sayings'... one applies in this case... "To trust-is-to-bust. To-bust is hell-to-pay. So... no-trust, no-bust, no hell-to-pay."

MZ... BTW... I love sharp-tongue quotes... I'm gonna add your words to my quotes listing, thus...

"So if I were you, I'd really let this one go - I have no idea which hill you would like to die on, but I really don't think it's this one." - MZ, Exalted Grand Poobah, MIT

I'm probably gonna regret this posting...
 

12notes

Well-Known Member
Lifetime Supporter
Log Member
Joined
Aug 27, 2014
Messages
1,235
Location
Louisville, KY
OK, guys, I think I need to expand on my concern with '...circles and arrows and a paragraph on the back'. Sorry if this 'read' is too-long...then... don't-read-it... TLDNR.

I have been 'active' in aviation since my dad started building his T18 in 1967 and when I soloed in 1968. THEN In 1974 I had an eye-opening safety incident at OSH while taking a ride in a highly altered T18... that came close to claiming my life [have I discussed this in a prior thread?]. I have been a working aero engineer, including mishap/accident investigator for/supporting general aviation/homebuilts... and the military... since April 1979. I am now the old guy I used to seek out. Enough of 'I'.

Certified aviation-grade parts/materials come with a price... but also [should] come with performance and confidence in their heritage. Non-aviation parts and materials are always wild cards... based on 'trust-me-its-OK'.

The case of a 'simple extruded angle', without mill-markings, at the center of our discussion is a classic case of judicious but 'inappropriate trust'. In truth, a carefully formed/bent angle made from [mill-marked] 6061-T4 or 2024-T3 sheet, same thickness, would be as strong and stiff as the unknown extruded aluminum angle from L/HD, same thickness, with no fillet radius... and the aviation heritage of YOUR bent angles would be unquestioned... and just as functional.

Note to MZ... with your credentials... You are obviously aware that human factors is a HUGE element for basic safety... personal and societal. Decisions made often have 'wicked-irreversible' consequences. Using non-aircraft parts and materials from 'Lowes or Home Depot [L/HD] airplane departments' can make sense if chosen/used wisely... but this wisdom takes time to learn... and it must be documented... and it must never become flippant or common. Unfortunately what should be a rare occurrence often becomes the go-to-expedient... second nature... why-bother-asking???

There will be people in this website who will see 'L/HD airplane department' as a way to save a bunch of buck$ without knowing the corresponding issues/risks, like YOU and I, DO.

YOU obviously have the skills/ability to judiciously choose materials... when even good A&P licensed and military mechanics simply make mistakes in judgement... after-all what really is the difference between a piece of sheet metal: L/HD-aluminum or 6061-O, -T4, -T42, -T6, -T62 and 2024-O, -T3, -T36, -T42, -T62, -T81 or 7075-O, -T6, -T62, -T73, -T76... bare and clad and industrial and aviation specification grades? Since YOU truly understand these differences, ATTABOY! All others should be very cautious... and ask... even with instrument panels.

Anything You can touch/grab/lean-on/fall-on inadvertently ARE subject to 'abuse loads'. Also, aluminum sheet/plate panels are also used as common 'electrical ground paths'... each of these metals/tempers has unique conductivity and long-term corrosion-potential at contact points.

AC43-18 FABRICATION OF AIRCRAFT PARTS BY MAINTENANCE PERSONNEL was written because of this very worriesome problem.... and is the essence of what has taken me ~40-years to grasp as second nature. I have wintessed 'good intentioned' mechanics... and fellow engineers... take unbelievable shortcuts and have brain farts... ALL...THE...TIME... without a clue... as to 'why' something 'had-to-be done by-a-book they've never read'.

My grandpa had his own roofing business in SoCAL from the early 1930s to late 1950s. He had lots of unique 'favorite sayings'... one applies in this case... "To trust-is-to-bust. To-bust is hell-to-pay. So... no-trust, no-bust, no hell-to-pay."

MZ... BTW... I love sharp-tongue quotes... I'm gonna add your words to my quotes listing, thus...

"So if I were you, I'd really let this one go - I have no idea which hill you would like to die on, but I really don't think it's this one." - MZ, Exalted Grand Poobah, MIT

I'm probably gonna regret this posting...
Once again, a lot of words, no new valid points, everything mentioned has been addressed in this thread already and you're still wrong. More words explaining a bad argument will not make you right.

Give it up already, like you said you would a week ago.
 

dwalker

Well-Known Member
Joined
Mar 6, 2021
Messages
362
Location
Tennessee
OK, guys, I think I need to expand on my concern with '...circles and arrows and a paragraph on the back'. Sorry if this 'read' is too-long...then... don't-read-it... TLDNR.

I have been 'active' in aviation since my dad started building his T18 in 1967 and when I soloed in 1968. THEN In 1974 I had an eye-opening safety incident at OSH while taking a ride in a highly altered T18... that came close to claiming my life [have I discussed this in a prior thread?]. I have been a working aero engineer, including mishap/accident investigator for/supporting general aviation/homebuilts... and the military... since April 1979. I am now the old guy I used to seek out. Enough of 'I'.

Certified aviation-grade parts/materials come with a price... but also [should] come with performance and confidence in their heritage. Non-aviation parts and materials are always wild cards... based on 'trust-me-its-OK'.

The case of a 'simple extruded angle', without mill-markings, at the center of our discussion is a classic case of judicious but 'inappropriate trust'. In truth, a carefully formed/bent angle made from [mill-marked] 6061-T4 or 2024-T3 sheet, same thickness, would be as strong and stiff as the unknown extruded aluminum angle from L/HD, same thickness, with no fillet radius... and the aviation heritage of YOUR bent angles would be unquestioned... and just as functional.

Note to MZ... with your credentials... You are obviously aware that human factors is a HUGE element for basic safety... personal and societal. Decisions made often have 'wicked-irreversible' consequences. Using non-aircraft parts and materials from 'Lowes or Home Depot [L/HD] airplane departments' can make sense if chosen/used wisely... but this wisdom takes time to learn... and it must be documented... and it must never become flippant or common. Unfortunately what should be a rare occurrence often becomes the go-to-expedient... second nature... why-bother-asking???

There will be people in this website who will see 'L/HD airplane department' as a way to save a bunch of buck$ without knowing the corresponding issues/risks, like YOU and I, DO.

YOU obviously have the skills/ability to judiciously choose materials... when even good A&P licensed and military mechanics simply make mistakes in judgement... after-all what really is the difference between a piece of sheet metal: L/HD-aluminum or 6061-O, -T4, -T42, -T6, -T62 and 2024-O, -T3, -T36, -T42, -T62, -T81 or 7075-O, -T6, -T62, -T73, -T76... bare and clad and industrial and aviation specification grades? Since YOU truly understand these differences, ATTABOY! All others should be very cautious... and ask... even with instrument panels.

Anything You can touch/grab/lean-on/fall-on inadvertently ARE subject to 'abuse loads'. Also, aluminum sheet/plate panels are also used as common 'electrical ground paths'... each of these metals/tempers has unique conductivity and long-term corrosion-potential at contact points.

AC43-18 FABRICATION OF AIRCRAFT PARTS BY MAINTENANCE PERSONNEL was written because of this very worriesome problem.... and is the essence of what has taken me ~40-years to grasp as second nature. I have wintessed 'good intentioned' mechanics... and fellow engineers... take unbelievable shortcuts and have brain farts... ALL...THE...TIME... without a clue... as to 'why' something 'had-to-be done by-a-book they've never read'.

My grandpa had his own roofing business in SoCAL from the early 1930s to late 1950s. He had lots of unique 'favorite sayings'... one applies in this case... "To trust-is-to-bust. To-bust is hell-to-pay. So... no-trust, no-bust, no hell-to-pay."

MZ... BTW... I love sharp-tongue quotes... I'm gonna add your words to my quotes listing, thus...

"So if I were you, I'd really let this one go - I have no idea which hill you would like to die on, but I really don't think it's this one." - MZ, Exalted Grand Poobah, MIT

I'm probably gonna regret this posting...

I am not sure why you are pursuing this in this manor-

IF we were talking a certified aircraft and some poor slob has his entire career on being able to blame someone else if a 1/6th piece of angle aluminum cracks, then OK, buy the documented from ore material, and let the customer cry about the increased costs in Certified Aircraft maintenance over his $30 16" piece of extrusion.

BUT we are not.

We are on a forum for homebuilders, for whom HomeDepot is a valid source of bits and pieces. My instrument panel is being made from foam and glassfibre with some carbonfibre thrown in for good measure, none of which comes from an "aircraft supplier". Even the MGS epoxy I am using came from a MODEL AIRCRAFT supplier, the foam from a marine store, and the carbon fibre from GADZOOKS!!!! Ebay.
 

proppastie

Well-Known Member
Log Member
Joined
Feb 19, 2012
Messages
5,228
Location
NJ
Time past (BR Before Rutan) it was a mantra at EAA "AIRCRAFT MATERIALS AND PROCEDURES".....I believe in the 50's the FAA insisted on it for hombuilt aircraft.
 
Last edited by a moderator:

Jsample40

Well-Known Member
Joined
Jan 18, 2020
Messages
61
Location
Western North Carolina
Real Life Crash Investigation Experience re: inappropriate materials incorporated into aircraft.

In the late 1970's, early to mid 1980's, there were many individuals (like myself) who were totally determined to "Get High" without drugs. We would strap an "engine" of any sort onto the front or rear of anything resembling "wings" and do our best to get airborne (regardless of the risks). Many of those folks have passed on to the great beyond... a great number due to their various forms of aircraft (including the early ultralights) being inadequate to the tasks (ie: forces being applied to the "structure" once airborne).

In the early 1980's, after noting many of my aviation buddies (and acquaintances) dying in aviation "Mishaps", with no one attempting to "investigate" the actual causes, I determined to find a way to resolve the issues in my region. The FAA would not investigate UL accidents... even fatal ones, as they did not consider UL's to be "aircraft". I assembled a small group of like minded folks including an aeronautical engineer, an individual familiar with stress analysis, several pilots, and myself.. to begin an attempt to determine what was causing the many crashes... and causing the deaths of my friends and acquaintances'.

It was named the Ultra-Light Accident Investigation Program (UAIP). We began travelling to the crash sites, taking measurements, pictures, and information from witnesses, including flying pals.
We were able to reconstruct numerous small aircraft in warehouses or hangars, and reproduce the path of body motion which tore the flimsy aluminum frames apart in midair.

In the midst of this I took my Mitchell B-10A to OshKosh 1982 and flew with Steve Patmont, the general manager & chief test pilot for Mitchell Wing in Porterville, CA. Following the event, Steve asked me to participate in a Mitchell B-10 fatal accident in Kentucky on my way home to Florida.

Two Mitchell Wing aircraft had been flying together at altitude, with one ahead of the other. The rear pilot witnessed the forward MW craft suddenly appear to be cut into two pieces, with the pilot and tricycle undercarriage falling to the earth far below. The local sheriff simply took pics of the crash scene and had the wreckage hauled to the owners hangar.... No cause was known or listed in the newspaper. No attempt to discern the causes by the FAA.

I was fortunate enough to be able to discern the astonishing cause while onsite. The aluminum undercarriage was largely intact, with the exception of the two 2" diameter vertical rear carriage support tubes, which also served as the support pillars for the engine mounts. The engine had separated from the aforementioned framework, and was complete though battered. I noted an odd issue in that the rope pull starter cord and handle were "hung" in a vertical split in one side of the two blade wooden prop. Additionally, there was a small round metal ring still captured on the pull cord. Further examination revealed that it was part of a cheap zinc coated metal screw eye which had been mounted by drilling thru the main rear support tube on the left side. The bolt portion was still installed on the 2" upright tube. Closer examination revealed the presence of rust on the two mating ends of the severed screw eye bolt which had served as a pull rope guide to hang the pull rope handle on. The pilot had purchased it from a local hardware store, and after numerous pull starts, had begun to crack the horizontal portion of the bolt component from the vigorous downward pulling motion required to start the engine.

The cheap, inadequate piece of hardware, cost the pilot his life in the following manner. When it broke in flight, the spring loaded recoil starter began retracting the pull cord. When the rope and handle encountered the spinning wooden prop, it split the outer end, and buried the rope in the split clear down near to the hub. The engine was stopped from approx 4,000 rpm to zero in an instant, creating a massive torque loading on the two vertical 2" rear support tubes, one of which had been drilled thru at a point 16" below its upper attach point to the rear of the Mitchell Wing wooden rear support member. The massive, near instantaneous torque loads severed both rear support tubes, allowing the undercarriage (with 200 lb pilot aboard) to swing an arc down and forward, causing the wing to violently pitch down, broadside to the airflow at approx 50 mph.

When the swinging mass of the undercarriage and pilot reached the upward limit of travel (the wood and foam "D" spar), it severed the entire wing structure into two separate halves, each floating down to earth separately. Unfortunately, the carriage and pilot were not so fortunate as to "float" down.... a hellish last ride that one can only imagine.

All because of a $.75 piece of crap zinc coated screw eye, coupled with drilling a 1/4" hole thru a main support tube in the mid portion of the unsupported part of the critical tube.

Apologies for the length of this post... but it certainly was a viable example of insuring the items or materials we incorporate into our "Sky Chariots" is made of the "Right Stuff".

Following the publication of this finding, the FAA requested the opportunity to accompany our small team to other crash sites, and incorporated our UAIP check lists and guide lines into their UL / experimental aircraft accident investigation activities in our region.

Respectfully,
Jay W. Sample
Former President of South East Ultralight Assn. & founder/developer of the UAIP process.
 

Marc Zeitlin

Exalted Grand Poobah
Joined
Dec 11, 2015
Messages
998
Location
Tehachapi, CA
... I'm probably gonna regret this posting...
You probably won't, given the previous evidence to the contrary.

In any case, my flummox exponent is now running somewhere in the 63 range.

This forum contains zillions of posts from folks installing 2 stroke lawnmower engines in ultralights, automobile/motorcycle/snowmobile/jetski engine conversions with homemade PSRU's in E-AB aircraft, aftermarket (non-certified) EI and EFII systems, homemade EFIS's made from Raspberry Pi's or Arduinos, wooden aircraft built from wood purchased at some random lumberyard, discussions of painting with latex paint and homemade electrical motor/battery systems (amongst a plethora of other "non-aircraft" material parts and components) but the thing that apparently chaps your a$$ is the fact that I used a HD AL angle with no provenance to brace an instrument panel in a COZY MKIV, and dared to mention it in a post about how to support instrument panels.

Fascinating...
 

Marc Zeitlin

Exalted Grand Poobah
Joined
Dec 11, 2015
Messages
998
Location
Tehachapi, CA
Written with all the respect in the world for someone interested in investigating accidents and making flying safer.

I'm curious what approved components are used in the fabrication of a Mitchell B-10 aircraft, and where those components are sourced? Or what components AREN'T "approved" aircraft components. I'm curious to see the PMA for the Zenoah G-25 engine, too.

Following the event, Steve asked me to participate in a Mitchell B-10 fatal accident in Kentucky on my way home to Florida.
Hopefully what he asked you to participate in was the investigation, not the fatal accident itself.

All because of a $.75 piece of crap zinc coated screw eye, coupled with drilling a 1/4" hole thru a main support tube in the mid portion of the unsupported part of the critical tube.
And the operative words here are:

"... hole thru a main support tube in the mid portion of the unsupported part OF THE CRITICAL TUBE".​

See what I did there? Point out the difference between doing something stupid, and doing something that doesn't matter in the least. I agree with you 100% that drilling a hole in a critical structural element and then putting loads on it in a way that it wasn't designed for is contraindicated. No one, least of all me, has suggested doing anything of the sort in Bill S's instrument panel, nor have I done so in mine or my customer's IP's.

C'mon, folks - context is everything.
 

dwalker

Well-Known Member
Joined
Mar 6, 2021
Messages
362
Location
Tennessee
Written with all the respect in the world for someone interested in investigating accidents and making flying safer.

I'm curious what approved components are used in the fabrication of a Mitchell B-10 aircraft, and where those components are sourced? Or what components AREN'T "approved" aircraft components. I'm curious to see the PMA for the Zenoah G-25 engine, too.

Hopefully what he asked you to participate in was the investigation, not the fatal accident itself.

And the operative words here are:

"... hole thru a main support tube in the mid portion of the unsupported part OF THE CRITICAL TUBE".​

See what I did there? Point out the difference between doing something stupid, and doing something that doesn't matter in the least. I agree with you 100% that drilling a hole in a critical structural element and then putting loads on it in a way that it wasn't designed for is contraindicated. No one, least of all me, has suggested doing anything of the sort in Bill S's instrument panel, nor have I done so in mine or my customer's IP's.

C'mon, folks - context is everything.

Thanks Marc, for pointing out the obvious.

I am exceedingly curious now though, what "right stuff" aircraft part would have taken the place of the eye bolt for the starter pull cord?



We are vastly far afield of the OP's inquiry, and still wandering..
 

Jsample40

Well-Known Member
Joined
Jan 18, 2020
Messages
61
Location
Western North Carolina
Written with all the respect in the world for someone interested in investigating accidents and making flying safer.

I'm curious what approved components are used in the fabrication of a Mitchell B-10 aircraft, and where those components are sourced? Or what components AREN'T "approved" aircraft components. I'm curious to see the PMA for the Zenoah G-25 engine, too.

Hopefully what he asked you to participate in was the investigation, not the fatal accident itself.

And the operative words here are:

"... hole thru a main support tube in the mid portion of the unsupported part OF THE CRITICAL TUBE".​

See what I did there? Point out the difference between doing something stupid, and doing something that doesn't matter in the least. I agree with you 100% that drilling a hole in a critical structural element and then putting loads on it in a way that it wasn't designed for is contraindicated. No one, least of all me, has suggested doing anything of the sort in Bill S's instrument panel, nor have I done so in mine or my customer's IP's.

C'mon, folks - context is everything.
Written with all the respect in the world for someone interested in investigating accidents and making flying safer.

I'm curious what approved components are used in the fabrication of a Mitchell B-10 aircraft, and where those components are sourced? Or what components AREN'T "approved" aircraft components. I'm curious to see the PMA for the Zenoah G-25 engine, too.

Hopefully what he asked you to participate in was the investigation, not the fatal accident itself.

And the operative words here are:

"... hole thru a main support tube in the mid portion of the unsupported part OF THE CRITICAL TUBE".​

See what I did there? Point out the difference between doing something stupid, and doing something that doesn't matter in the least. I agree with you 100% that drilling a hole in a critical structural element and then putting loads on it in a way that it wasn't designed for is contraindicated. No one, least of all me, has suggested doing anything of the sort in Bill S's instrument panel, nor have I done so in mine or my customer's IP's.

C'mon, folks - context is everything.
Hi Marc;
Thank you for your inquiry re: Mitchell Wing matters. As to the preferred materials, in my case, I ordered the materials package and design drawings from Steve Patmont at Mitchell Wing in Porterville, CA around 1980- 81. The initial 4 "down tubes" that connected the wing structure to the tricycle undercarriage were 2" diameter 6061 aluminum (single thickness initially).

Following the results of our onsite Kentucky investigation, I suggested to SP at MW that we either double the wall thickness or insert an inner, slightly smaller aluminum tube in all 4 main support tubes... the latter of which I did, and which became the subject of a safety bulletin from MW.

As to the Kentucky accident, it is important to note that it was the small, cheap eye bolt failing partially (apparently by work hardening), then rusting, then parting in flight that set the entire catastrophe into motion.... not the hole bored (stupidly) in the middle of the unsupported portion of the main rear support tube.

And as to the invitation to the Kentucky "accident" (forgetting to attach "investigation"), I plead Nolo Contendre. Just due to the fact of pushing 81 years in this life cycle on this small blue planet.
Sincere Affinity to another "Birdman"
Jay
 
Top