a couple printed widgets

[A2022]

Lightspeed Delta Zulu headset control mount... test fit. V1 and V2 mounted on the test stand. they are both good, but I choose V2. secure in any orientation, even upside down. a couple free mounts and the headset will be returned to the owner today. 5-day turn time from receiving the headset. with shipping he should have it back in 7 days. it really is all about SPEED. part weight = 36 grams. aviation: where you pay more to get less (weight).

this part can only be mounted with 3M Dual Lock.

[A2022]

RV8 cockpit bulkhead hole cover.... a guy was asking for something here I suppose to prevent boot dirt or other stuff falling in the hole, or perhaps to seal this area from drafts. I said I would take a look at it because I did something similar for an instrument hole cover. that part never did get much attention but at least it showed a design concept. it is weird that I the same week I took that part off the website this comes up. the website has 150 parts on there, so I need to slim that down.

RV8 hole cover to go here.

Requirements:
1. Cover the 4 holes
2. To be easily removable
3. To be secure
4. To not snag on the foot and have no protrusion features




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the previous instrumentation panel cover I made several years ago. I need to remake this design so that the geometry adjusts properly with hole size. I will also consider 4 spring tabs as well as 2. I am not sure if that is needed but you really don't want one of these to become free and snag your foot while landing. I remember that setting the tab angles and distances for closure to hold cover was tricky. For now, I am going to hangar because it is supposed to be 23C today (what's going on with the weather? where is Winter?). I already started a couple GPS Dock prints and some other stuff, so let them run because they take a while.

but also need to think of other possible designs and not limit myself to this concept.

[A2022]

RV8 cockpit bulkhead hole cover... 2-tab version is ready for test print. 4-tab version needs some work. needs to be strong enough to take a kick.









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cycled the latches 100 times and I see a little crack at one edge. I'll need to think about that. printing in a different orientation to the panel hole cover. tomorrow looks like a good day to fly.

Visit Us - Sporty's Pilot Shophttps://www.sportys.com › visit-us
Every Saturday between noon and 2pm, we grill hot dogs, metts and brats in appreciation of our customers. While you're here, shop our retail store.

I should take my Tabasco Scorpion sauce for the dogs.

[A2022]

RV8 cockpit bulkhead hole cover.. most of the problem with the tab is the curved shape of the part that bends. have you ever tried to bend curved sheet metal. it's doesn't work very well. I made the tab straight and took a better look at it. it's getting better but would like to reduce stress by 10MPa for margin. squeeze reaction force = 20 lb. so, it's either a thinner or deeper tab.

[A2022]

RV7 elevator gust locks, .125 inch thick. this gap size is good.

some make the gap between the elevator and stab so tight you cannot get a credit card in there. if you have a bird strike in the wrong place or ice buildup, the elevator could become jammed, and it could be a bad day. it is best to allow for margin. speed wise, it may cost you 1/4 kt. a tight gap = high risk for minimal gain. if you are forced to go through a flock, be in a shallow climb. never a hard nose down.

[A2022]

RV8 cockpit bulkhead hole cover.... reduced the stress by extending the retaining tab. 500 cycles and so signs of any cracking. it's stiff so probably only need 2 tabs required if the hole cutout dimension is accurate. need to verify. you know, goofy RV8 drivers trying to take a measurement with a plastic vernier caliper. I've seen it, crazy! you build a $200K machine and then measure it with a $2 plastic caliper? hand it to me and I'll snap it over my knee, done. one of the characteristic differences between humans and animals is that humans have the capability to be precise. in whatever you do, always be precise. my German heritage coming through.

solution converged in 31 iterations. the squeeze force on this tab to the stop is 13.64 lb.

[A2022]

RV8 cockpit bulkhead hole cover... taking a look at the instantaneous center of rotation for the hinge for two configurations. the engagement surface is affected by the hinge (vertex) location. it is better to keep the vertex as far outboard as possible but there needs to be enough clearance to fit it. I am sure I am not the first person in history to look at this, but it has been fun. as the tab sweeps inwards the rotation center changes. Version 9 is preferred over Version 8 because the engagement surface is higher. hey, I learned something. that makes it a good day. it's all about the geometry! (Euclidian) add some fillets and chamfers and take one more look. getting closer. 12 lb force to deflect this hinge fully.

Way Out West - We Love Machine (especially, machines that fly)
https://youtu.be/QqvozY2mFJI


Version 8







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Version 9





















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slot shaped




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if I go back and take a look at the original version with the curved hinge you can see the stress concentrating at the edges. this failed within 100 cycles. compared to the starting point, the stress was reduced 35% to 36 Mpa in the final version.

curved hinge, not good for maximum life.

[A2022]

RV8 cockpit bulkhead hole cover...I have a failure but really a success. fatigue testing the panel hole cover retainer to 1627 cycles to the max stop. it had good force until the snap as it caught me unaware. since Low Cycle Fatigue (LCF) is primarily a function of the max stress (lower stress cycles don't count for much, Miner's Rule, do the math) and the retainer does not bend to the max stop during normal installation and removal, it can probably survive twice as many cycles for normal use, but this is not a statistical test, just one. how many cycles will this part have during it's normal lifetime, probably not over 100.

50 cycles tested at a time. my thumb is sore.

if this was a new turbine disk, you would determine the probability of a defect in all the disk critical regions and then determine the life of those regions and then combine them to have a life for the disk. then divide that number by 3 and that would be the starting life for that part. after some experience, work a life extension program with refined analysis and experience to extend the life. for turbine design it is statistical. do you understand how much energy is released when a turbine disk burst? you don't want to know, and no structure can contain except a really thick concrete wall. when they burst, such as in a dedicated burst test, it is usually 3 pieces. think about that the next time so sit by the engine on an airliner. mechanical engineering at the highest level. need to buy one new replacement high pressure turbine disk for a large engine? probably about 3M dollars but it may be higher by now.







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pump up the techno polka! probably good to dance to after a couple beers.

Tinlicker - Oudegracht (Official Tinlicker Channel)
https://youtu.be/Tle_t4kMxO4




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a message from the owner who received the free Delta Zulu control mount holders for letting me use his headset for a pattern...... nice to hear it is working fine. sail on!

I keep trying to remember to get a photo. I mounted mine in my 8 low on the bulkhead that attaches to the main spar. It’s gonna be hard to see, but I promise I’ll remember….. Works great by the way!!!

[A2022]

RV8 cockpit bulkhead hole cover... installed. doesn't look too bad. it is reported that the brass nut is not needed. user mentioned it is a good fit so it should be secure.

[A2022]

RV8 cockpit bulkhead hole cover... since the top hole has a brake line passing through, a slot will need to be cut at the edge, so I added a couple ribs for those to add stiffness. printers are humming this AM and I'm going for a bike/airplane ride. looks like a nice day to go somewhere new.