Van's Air Force
Don't miss anything! Register now for full access to the definitive RV support community.
Vans engineers having a laugh
- Thread starter Vansrv7arob
- Start date
Little Mark
I had a guy working for me and his nick name was "Little Mark." I asked him what was the source of the nick name and he said: Right out of high school the foreman sent me to go take a measurement, I climbed up the latter and called out - 121 inches ...... and 9 little marks.
So I call the Van's CAD guy: Little Mark.
I see the crazy tolerance markings all over the plans, but they are fun to try to and achieve. So how do you mark 1/64"? Mid point between the 1/32 marks.
I had a guy working for me and his nick name was "Little Mark." I asked him what was the source of the nick name and he said: Right out of high school the foreman sent me to go take a measurement, I climbed up the latter and called out - 121 inches ...... and 9 little marks.
So I call the Van's CAD guy: Little Mark.
I see the crazy tolerance markings all over the plans, but they are fun to try to and achieve.
So how do you mark 1/64"? Mid point between the 1/32 marks.
DaleB
Well Known Member
How do I mark 1/64"? With a Sharpie!I see the crazy tolerance markings all over the plans, but they are fun to try to and achieve.
Of course I've tried marking with a Sharpie, then lightly scribing the precise location on the part. Then center-punch -- oops, it's about 1/64th off -- drill -- dang it!! Drill press wandered off another 1/32 in the other direction... and it ends up "in the vicinity". I eventually learned to offset the work in the drill press to keep that part to a minimum.
AeroLEDs_Support
Well Known Member
Yes, the per each hole placement accuracy isn't to 1/32 of an inch, but if there are 32 holes along that edge, they do need to be roughly spaced at 1 and 1/32 because by the time you get to the end of that row of holes, 32 holes add up to an additional 1 inch, so if you spaced them at 1 inch you'd have a 1 inch gap left at the end of the row. I think that is the reason for the 1 and 1/32 call out.
E. D. Eliot
Well Known Member
Engineers
Not calling anyone out here. Engineers are engineers - they deal with 1/000s of an inch sometimes (like when they send instructions to the machines that 'punch' out the critical pieces of our kits. Its a mind set. They are taught to be as accurate as possible. I like that.
I strive, like most, to be accurate but when I fail, I don't worry about it if I'm off by 1/64 or 1/32 if the part dimension is not critical. It the measurement is critical, its time to purchase a replacement part and get it right with the next new part.
I've known a few engineers and almost without exception, the ones who have spent some time building what they have drawn out have respect for those of us who are building what they have specked out. The ones who bug me are the ones who have no respect for us who build their projects. I think that most or all of Van's engineers respect us builders and try to spec out the measurements as accurately as possible. I like that too.
Not calling anyone out here. Engineers are engineers - they deal with 1/000s of an inch sometimes (like when they send instructions to the machines that 'punch' out the critical pieces of our kits. Its a mind set. They are taught to be as accurate as possible. I like that.
I strive, like most, to be accurate but when I fail, I don't worry about it if I'm off by 1/64 or 1/32 if the part dimension is not critical. It the measurement is critical, its time to purchase a replacement part and get it right with the next new part.
I've known a few engineers and almost without exception, the ones who have spent some time building what they have drawn out have respect for those of us who are building what they have specked out. The ones who bug me are the ones who have no respect for us who build their projects. I think that most or all of Van's engineers respect us builders and try to spec out the measurements as accurately as possible. I like that too.
The dimension on the drawing has to be something. 1" or 1 1/32" what's the difference, you still need to use a scale and measure it to 1/32" accuracy. I found it to be no additional work to measure and mark to 1/32. As mentioned in a previous post, The tolerance stack up starts with the measurement, gets worse with the mark, center punch, and drilling. Minimize error at each step and you will be amazed at how much better it fits together. Be off high at each step and you will be short ED.
And yes, I am a aerospace design engineer.
And yes, I am a aerospace design engineer.
Not an engineer of this type but I would imagine that they use CAD and have the program space the rivet holes appropriately and these measurements is what the program will come up with. Nothing wrong with providing a more accurate measurement and let people do to their best of their ability to adhere to it. Besides, if you have 32 of these rivets in a row and rounded off by 1/32, now you have put one less rivet.
We have to thank modern technology, modern practises and a little bit of irony in this.
Now, as a Brit, we understand irony, not usually an understood thing in the Colonies.... But.
There is an interloper.
There is a Brit in Vans and we think, possibly, that his wit and wisdom is seeping into the very fabric of the organisation.
Why would you see an instruction in the 12 plans to use a 'metric crescent wrench' to - err facilitate the longerons ?
Come on chaps (and chappesses), the Engineers are playing with us.
They must sit with their Pabst beers, maybe Milwaukee, will will defer, and say - hey, how can we p1ss these guys off with using such tiny, weenie measurements as to sent them insane ?
It is Engineer amusement.
Let us all laugh collectively, let us all raise a glass of weak, domestic lager to them and say - thanks guys, thanks for making the best designed, the best supported and the best flying Experimental airplanes on the market today.
Rejoice, do not criticise.......
Now, as a Brit, we understand irony, not usually an understood thing in the Colonies.... But.
There is an interloper.
There is a Brit in Vans and we think, possibly, that his wit and wisdom is seeping into the very fabric of the organisation.
Why would you see an instruction in the 12 plans to use a 'metric crescent wrench' to - err facilitate the longerons ?
Come on chaps (and chappesses), the Engineers are playing with us.
They must sit with their Pabst beers, maybe Milwaukee, will will defer, and say - hey, how can we p1ss these guys off with using such tiny, weenie measurements as to sent them insane ?
It is Engineer amusement.
Let us all laugh collectively, let us all raise a glass of weak, domestic lager to them and say - thanks guys, thanks for making the best designed, the best supported and the best flying Experimental airplanes on the market today.
Rejoice, do not criticise.......
Further to last and being a little cagey....
Put a search into Google for Stanley RCH tape.
Now,
All I am saying is that some years ago, Stanley - apparently as a Christmas ruse, issued a tape that was calibrated in a very, very fine measurement.
It proved a great hit and many Engineers and Contractors are thankful for the accuracy it gave them.
Put a search into Google for Stanley RCH tape.
Now,
All I am saying is that some years ago, Stanley - apparently as a Christmas ruse, issued a tape that was calibrated in a very, very fine measurement.
It proved a great hit and many Engineers and Contractors are thankful for the accuracy it gave them.
The Xenos we're building has all dimensions to the nearest 1/64th - and if you hold to those tolerances, things fit together beautifully. The typical Sharpie line is about 1/32" wide, so yes - you have to place them all very carefully to get things right.
rv7boy
Forum Peruser
I'm glad you said "most" as I am an engineer and I've known several engineers who have wonderful senses of humor, even about dimensions.
One of my all-time favorite engineer jokes (apx. 40 years ago) was a cartoon of two young 15th century engineers looking at a large set of engineering drawings as a Tower in the city of Pisa, Italy was being built in the background. One engineer says to the other, "I skimped a little on the foundation, but no one will ever know the difference!"
Typical
Hi Rob,
I see in your video that you interpret the term "typical" specified in the plans as meaning "approximate". This is not the case. In this type of engineering drawing, typ, or typical means that this measurement is common to all relative sub sections of a part. This is commonly used when defining rivet pitch, or distance inboard from an edge, as can be seen in the examples below, rather than having to specify a measurement for each position. You are not alone with this misunderstanding, as I have seen others on this forum make a similar mistake in the past, so I'm just trying to give you and others a heads up.
Regards,
Tom.
Hi Rob,
I see in your video that you interpret the term "typical" specified in the plans as meaning "approximate". This is not the case. In this type of engineering drawing, typ, or typical means that this measurement is common to all relative sub sections of a part. This is commonly used when defining rivet pitch, or distance inboard from an edge, as can be seen in the examples below, rather than having to specify a measurement for each position. You are not alone with this misunderstanding, as I have seen others on this forum make a similar mistake in the past, so I'm just trying to give you and others a heads up.
Regards,
Tom.
Last edited:
Hi Rob,
I see in you video that interpret the term "typical" specified in the plans as meaning "approximate". This is not the case. In this type of engineering drawing, typ, or typical means that this measurement is common to all relative sub sections of a part. This is commonly used when defining rivet pitch, or distance inboard from an edge, as can be seen in the examples below, rather than having to specify a measurement for each position. You are not alone with this misunderstanding, as I have seen others on this forum make a similar mistake in the past, so I'm just trying to give you and others a heads up.
Regards,
Tom.
^^^^^^^^^^
Correct
And, If a drawing is being made for reference to building something, it is rare that the person reading the drawing would be happy with a dimension listed as "not important.... Make it whatever works".
BTW, the canopy on my airplane doesn't leak........
Sam Staton
Well Known Member
Standard phrase
"Measure with a micrometer, mark with a crayon, cut with an ax."
"Measure with a micrometer, mark with a crayon, cut with an ax."
to get to the desired end result pull a tape measure the entire length of the layout and keep adding 1 1/32'' to the measurement on the tape. in the end your holes are evenly spaced [i know, obvious and everyone already does it].
vans could just as easily said make 30 holes evenly spaced and YOU would have been the one calling out 1 1/32''.
vans could just as easily said make 30 holes evenly spaced and YOU would have been the one calling out 1 1/32''.
humptybump
Well Known Member
Disclaimer: I'm a buyer, not a builder. I'm also "work with wood".
The default marking tool in my shop for the past decade has been 0.5mm mechanical pencil. Unfortunately it's not great on aluminum or polycarbonate.
It's a bummer when the construction tolerances exceed the marking device
LettersFromFlyoverCountry
Well Known Member
I was home visiting my 94 year old mother -- why of course I flew my RV-7A halfway across the country to get there; that's why I built an RV-7A -- last month and as we sat on the porch, she decided to go get a book full of recipe's that her mother -- my grandmother -- had put together over the years.
The yellowing paper was so crisp from time that it would break if I wasn't careful turning the page from brown bread to molasses cookies. Man, I loved those molasses cookies.
Everything was there in great detail... baking powder to the teaspoon, sifted flour to the cup, the order in which eggs needed to be folded into the batter.
There was only one thing missing from EVERY recipe:
How much time it needed to bake and at what temperature the oven needed to be.
That wasn't the way they did things back then. You made your recipe and you shoved it in the oven and it was done when it was done.
You know who I thought about at that moment while sitting on the porch with my saintly mom? Paul Poberezny and Tony Bingelis and all those people who built -- not assemble from kits -- airplanes.
Back when I was building -- well, assembling -- my RV-7A, I'd occasionally feel aggrieved by some confusion on the plans or Ken Scott's narrative or whatever. I'd always think about those people who didn't have the luxuries of today. The ones we take for granted.
Assemble on!
The yellowing paper was so crisp from time that it would break if I wasn't careful turning the page from brown bread to molasses cookies. Man, I loved those molasses cookies.
Everything was there in great detail... baking powder to the teaspoon, sifted flour to the cup, the order in which eggs needed to be folded into the batter.
There was only one thing missing from EVERY recipe:
How much time it needed to bake and at what temperature the oven needed to be.
That wasn't the way they did things back then. You made your recipe and you shoved it in the oven and it was done when it was done.
You know who I thought about at that moment while sitting on the porch with my saintly mom? Paul Poberezny and Tony Bingelis and all those people who built -- not assemble from kits -- airplanes.
Back when I was building -- well, assembling -- my RV-7A, I'd occasionally feel aggrieved by some confusion on the plans or Ken Scott's narrative or whatever. I'd always think about those people who didn't have the luxuries of today. The ones we take for granted.
Assemble on!
Last edited:
snopercod
Well Known Member
When I was a field engineer on the Space Shuttle program, one of my jobs was installing the Tail Service Masts [TSMs] on Mobile Launch Platform - #3. This was the former Mobile Launcher -1 that had launched Apollo 11 to the moon but had been converted from a one-holer to a three-holer for the Shuttle. The TSMs are those tombstone-shaped structures on either side of the aft end of the Orbiter through which the liquid oxygen and liquid hydrogen (and a bunch of other stuff) flows during the launch countdown. The TSMs each weigh 67 tons, and had to be set on the MLP within 1/8" in all three axes so all the "plugs" would line up to the Orbiter.
We had a survey crew with theodolites and fancy computers which they used to determine exactly where the TSMs were sitting in all three axes. After the 250 ton crane placed the first TSM on the deck, the survey guys were all scratching their heads because the height of the opening at the top was 3/8" off after they had previously checked everything within a few thousandths of an inch. I happened to be carrying my Stanley 25' tape measure on my belt so I climbed up inside the TSM and measured from the opening down to the deck; It was right on.
When I approached the surveyors with this information, they all laughed hilariously. "We've got millions of dollars of high-tech equipment here and you think your $10 tape measure is more accurate?" They came over to me about an hour later and admitted that my tape measure was correct after all. The coordinate system on the Shuttle is "backwards" in the vertical direction and they had entered a positive number in their computer rather than a negative.
After that, whenever I'd see those guys around the Center, they'd always yell, "Hey! Can we borrow your tape measure?" LOL!
We had a survey crew with theodolites and fancy computers which they used to determine exactly where the TSMs were sitting in all three axes. After the 250 ton crane placed the first TSM on the deck, the survey guys were all scratching their heads because the height of the opening at the top was 3/8" off after they had previously checked everything within a few thousandths of an inch. I happened to be carrying my Stanley 25' tape measure on my belt so I climbed up inside the TSM and measured from the opening down to the deck; It was right on.
When I approached the surveyors with this information, they all laughed hilariously. "We've got millions of dollars of high-tech equipment here and you think your $10 tape measure is more accurate?" They came over to me about an hour later and admitted that my tape measure was correct after all. The coordinate system on the Shuttle is "backwards" in the vertical direction and they had entered a positive number in their computer rather than a negative.
After that, whenever I'd see those guys around the Center, they'd always yell, "Hey! Can we borrow your tape measure?" LOL!
Weasel
Well Known Member
I like presicion
One time I drilled the cowl hinge from the firewall of a quickbuild -10 kit and riveted the old hinge on a new quickbuild -10 kit in the pre punched holes. Installed the old engine, engine mount and rubber engine mount bushings and cowling.
The spinner lined up to the cowl exactly like it was on the old fuselage.
One time I drilled the cowl hinge from the firewall of a quickbuild -10 kit and riveted the old hinge on a new quickbuild -10 kit in the pre punched holes. Installed the old engine, engine mount and rubber engine mount bushings and cowling.
The spinner lined up to the cowl exactly like it was on the old fuselage.
rv7boy
Forum Peruser
OMG I feel so old. Not one mention of a rivet fan so far. That was a basic tool for us non-PP builders. No need for tolerances. Just even spacing that found all the tabs and missed the flutes. Kids...
Yeah, Avery and Cleaveland used to sell a bunch of them before the pre-punched kits came along. Sometimes I wish I had one, but I hardly ever see one for sale.
f1rocket
Well Known Member
One of my favorite quotes from Mark Frederick (Team Rocket) when asked a building question, "Think garden tractor, not space shuttle!"
Disclaimer: I'm a buyer, not a builder. I'm also "work with wood".
The default marking tool in my shop for the past decade has been 0.5mm mechanical pencil. Unfortunately it's not great on aluminum or polycarbonate.
It's a bummer when the construction tolerances exceed the marking device
What is the difference, in terms of difficulty, between putting the mark on the 1 and 1/32" line or the 1" line? 0.5mm is 20 thou (ish). Just because that is more than half of 1/32" you can still like up the center of it with the center of the line, and mark the center of the line with a hole punch. As long as the ruler is put in the right place you will end up with more or less even spacing, even if some of the holes are 20 thou either side of the nominal location. It's all about using judgment. There is no question that the designer had to add the 1/32" to make the spacing work. It was not done as a joke.
If you own one of these, you know that they are not that accurate between centers........
They just work, and really cut down layout time...... it is fun to build this way....
flion
Well Known Member
Incra ruler. The page shows them using 0.5mm pencil in the holes and it's difficult to find a pen in that size but the but the edges are also scalloped at the markings and a scribe fits in there just fine. No harm in scribing where you are going to cut or drill anyway.
Nice find! I'm getting one ...
If you own one of these, you know that they are not that accurate between centers........
They just work, and really cut down layout time...... it is fun to build this way....
They do quite well - as long as you remember to use a Sharpie in the holes and not a drill bit.
Z-EDD
Well Known Member
I have no problem measuring to 32nds. What irritates me, and I know this isn't Vans fault really, is that 32nds can only be odd numbers! Even, and they suddenly morph into a whole different unit, 16ths or, heaven forbid, 8ths! You could call them "little marks" for all I care, just something consistent for all measurements would be most welcome to this child of the metric system
Btw, I am building a -7 but I have a rivet spacing fan, provided in my tool kit from Cleaveland. I used it just the other day on one of the parts shown above, the F-684 gusset. The spacing came out within, yup, about 1/32nd of the "typical". Handy tool indeed.
Btw, I am building a -7 but I have a rivet spacing fan, provided in my tool kit from Cleaveland. I used it just the other day on one of the parts shown above, the F-684 gusset. The spacing came out within, yup, about 1/32nd of the "typical". Handy tool indeed.
longranger
Well Known Member
OMG I feel so old. Not one mention of a rivet fan so far. That was a basic tool for us non-PP builders. No need for tolerances. Just even spacing that found all the tabs and missed the flutes. Kids...
I had one from my RV-4/HRII project. I've used it a couple of times on my RV-7, most recently on the seat backs, which are not prepunched.
Sharpie, nope.... I just center punch right through with a spring loaded center punch.
