Prog: Tail Wheel Plates

[Brian Jackson]

G'day all.

Well I spent the past couple of days thinking about how I was going to make QB's tail wheel plates. The basic geometry and hole locations are stock to plans, except I wanted a little more "shape". (Note: no material was removed from the stock profile to add the curved shape.)

http://www.gyrobuilder.com/qb/twp/1-twp.jpg
I'm reminded of the saying "When the only tool you have is a hammer, then it's OK to pound a screw" :) Since our printer cartridge died and replacing it is beyond our budget at the moment, I had to concoct an alternative method to generate a pattern.

As stupid as the above photo looks, it actually worked quite well. I zoomed in on the CAD model until it was scaled exactly 1:1. Overlayed a sheet of thick paper, turned the screen brightness to maximum, then carefully traced the outline of the part. Talk about low-tech! :D

http://www.gyrobuilder.com/qb/twp/2-twp.jpg
After cutting out the pattern with scissors (shown above), I coated the aluminum plate stock with blue dye and adhered the pattern to the plate with 2-way tape, lining it up with the straight top edge. Then, using a scribe, I traced the pattern into the dye.

http://www.gyrobuilder.com/qb/twp/3-twp.jpg
A band saw would have made the next 2 steps way-easier, but I used what I had... in this case a hack saw. I began removing as much material as possible with straight cuts around all the outside curves...

http://www.gyrobuilder.com/qb/twp/4-twp.jpg
...but the inside curve was tricky. As carefully as humanly possible I free-handed tiny slivers at a time using just the corner of the teeth on the table saw. I used this method for nibbling out the inside curves of my engine mount diagonals too, but I wouldn't recommend this technique for ANY builder unless it was truly a last resort.

...continued...

[Brian Jackson]

...continued...

http://www.gyrobuilder.com/qb/twp/5-twp.jpg
After using a disc sander to finish and blend all the outside curves I used this drill-press drum sander to finish off and smooth out the inside curve, using my fingers to check that all the curves blended smoothly into each other. Afterward I changed to a fine grit and semi-polished the edges. This way, light reflections on the edge would reveal any irregularities in the curvature.

http://www.gyrobuilder.com/qb/twp/6-twp.jpg
Lastly, I hand-filed the edge corners and presto. Now I have a hard shape to trace around to make the opposite part... and do this all over again :eek: Next I'll transfer-punch their hole locations from the existing holes in the tailboom.

Whew! Break time.

Brian

[RotoTony]

Looking good as usual Brain.
Tony

[banaari]

Looking good as usual Brain.
Tony

I like it... anybody see the Animaniacs cartoons?:
"What are we going to do tonight, Brain?"
"Same thing we do every night, Pinky: Try to take over the world..."

and

"Are you thinking what I'm thinking, Pinky?"
"I think so Brain, but where are we going to find a yak and some rubber tubing at this time of night?"

But I digress - the tail plate is the standard masterpiece now expected of the Jackson Skunk Works... :D

[REDHORSE556CES]

Ingenious! You have a very inventive mind!

Me? I would have used spray-on rubber cement to glue the pattern to the metal.....(messy). I would have used a jewelers saw for the inside curve....(wayyyy too tedious!)

"Pinky! Are you thinking what I'm thinking?"
"I think so Brain, but...this time you get to put the pants on the chimpanzee! NARF!!!"

[donshoebridge]

Hey Brian,

The small text in the bottom right corner of your monitor, doesn't that say "DO NOT SCALE DRAWING"? :D

How close was the aspect ratio of the part when finished? Was it dimentionally correct?

[Brian Jackson]

Hey Brian,

The small text in the bottom right corner of your monitor, doesn't that say "DO NOT SCALE DRAWING"? :D

How close was the aspect ratio of the part when finished? Was it dimentionally correct?
I wrote that in the title block as a disclaimer so I can't sue myself if I screw up the part :D

Yes, X & Y are spot-on. I make it a habit to calibrate the monitor before I use (or right after I install) any CAD program. Used to drive me nuts when I'd use others' workstations, and circles appeared as ellipses 'cause they never bothered to set the aspect ratio. Arrrr :eek:

[Brian Jackson]

Got the other plate finished today. Would never have thought these plates would take the better part of a week, but I'm happy with how they turned out, which is all that matters I suppose. :)

The snapshot (attached) shows the 2 plates stacked. I was a little nervous how closely they would match, considering there's only one straight side. It was pretty surprising that when put together there's no detectable difference. Dumb luck maybe?

Anyway, hopefully by tonight they'll be drilled and mounted to the tailboom. Then again, at the rate things are going it's likely to be another day or two. :D

Cheers,
Brian Jackson

[Brian Jackson]

By the way, I never bothered to ask if these "progress" posts were useful, or too much detail, or simply annoying. If it's too much I can tone it back and just hit the highlights. I tend to focus on details that might not be necessary on this forum.

[banaari]

Useful, informative & above all, *motivational*.

Particularly good to read on cold wet nights when I'm shattered from work and wavering between simply crashing in front of the fire, or wandering down to fabricate "just one more piece..."

So keep posting. :)

cheers,
John

[Brian Jackson]

Somehow I just knew there'd be no way in hell I'd have these plates installed 2 nights ago. Mental note: always multiply your time estimate by a factor of 3 :D .

http://www.gyrobuilder.com/qb/twp/install/1-twp-marking.jpg
Though both plates are identical, I dye marked each (inside left & inside right) because there's no guarantee that the exit holes on the tailboom are in exact alignment with the entrance holes (they were thru-drilled). So the hole patterns could differ by a couple thousandths of an inch. So this was just a safety measure to make sure each plate was transfer-punched and mounted to the same side.


http://www.gyrobuilder.com/qb/twp/install/2-twp-micrometer.jpg
Next I had to figure out a way to ensure both plates were mounted in mirror-image fore/aft positions, made more difficult because the fronts are curved instead of a straight edge. From the CAD model I determined that the forward tangent of the plates was 3.863" from the end of the tailboom. So this distance was scribed with a micrometer into the layout dye.


http://www.gyrobuilder.com/qb/twp/install/3-twp-squaring.jpg
Using a square held against the top surface of the tube, I lined up the rule with the mark I'd just made with the micrometer. I could then position the plate where it made contact with the 2 surfaces on the square. The plate was then clamped in place... (this is where having 4 arms, or a really nice wife, is helpful :D )


http://www.gyrobuilder.com/qb/twp/install/4-twp-drilled.jpg
Once the plate was clamped, I transfer-punched the hole centers from the other side of the tube. Drilling & deburring was pretty straight-forward from there. (My middle finger is really starting to callus over from that deburring tool! :eek: Yowza!)

...continued...

[Brian Jackson]

...continued...


http://www.gyrobuilder.com/qb/twp/install/5-twp-final.jpg
Finally after toiling and braining over this for a week, they're finished.

http://www.gyrobuilder.com/qb/twp/install/6-twp-endview.jpg
Another view. By the way, nothing has been polished or Scotch-Brited yet. Just noticed on the photo that what appear to be scratches, aren't. It's just the way the light is hitting the little micro-abrasions after parts get slid around on work surfaces.

Anyway, there it is. I'm pleased with how this turned out. Granted it would have been much easier to just square-cut everything, especially considering these plates aren't predominant items of the ship. But seeing them finished made all the extra effort worthwhile. And I really like how the shape kinda "softens" the design.

Now... what's next? :)

[RotoTony]

Looking Good! Your posts inspire all the gyrobee builders.
Tony

[Brian Jackson]

Looking Good! Your posts inspire all the gyrobee builders.
TonyThanks, Tony, that means a lot. Wasn't sure if these posts were of interest or just sucking up bandwidth :D . Had I been blessed with a well-equipped shop, or even had back some of the tools stolen from me recently, these posts may have been an afterthought at best. So perhaps, if nothing else, they show what can be done with little more than a drill, saw and file.

Thanks again,
Brian Jackson

[Allantat]

Brian. Keep up the posts. You keep proving the old saying...."Necessity is the mother of invention"

[Jazzenjohn]

...And the father of invention is usually the pizza delivery guy...

[martylunsford@h]

Brian, I'm just starting to build, and these posts are extremely helpful. Do you have a website where you are logging all of this valuable info? I know the threads will get deleted eventually, and I'd hate to remember seeing something I wanted to reference, but not being able to find it because it had been deleted.

BTW, I'm the guy who asked you about your 3D model. If you sent it to my email address, please try again, it may have gotten lost in the ether.

[Brian Jackson]

Brian, I'm just starting to build, and these posts are extremely helpful. Do you have a website where you are logging all of this valuable info? I know the threads will get deleted eventually, and I'd hate to remember seeing something I wanted to reference, but not being able to find it because it had been deleted.

BTW, I'm the guy who asked you about your 3D model. If you sent it to my email address, please try again, it may have gotten lost in the ether.
Hi Marty.
Sorry about the model. I thought I'd sent it, but ya never know when that Alzheimers kicks in :D .

Thank you for the kind feedback. I do have a website, but currently it's just server space. I did have a "Construction Diary" a while back, but my business partner kinda wigged out and the site evaporated. I do plan to make the photos & dialog available on a separate site soon, it's just a matter of finding the time to design it.

Keep us posted of your build. This forum is a wonderful place to share ideas, as you've witnessed. There's some truly smart folks here, and I'm learning quite a lot from them.

Regards,
Brian Jackson