I fly larger planes for a few reasons, primarily easier to fly and easier to see. Gas powered planes generally are larger than glow, I like both but gas is cheap, cleaner and more powerful.
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Converting my old pneumatic retracts to electric.
- Thread starter Flyinfool
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I fly larger planes for a few reasons, primarily easier to fly and easier to see. Gas powered planes generally are larger than glow, I like both but gas is cheap, cleaner and more powerful.
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- Dec 18, 2022
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I like my spirit 101.....
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- Apr 29, 2019
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One down.
I took the RPC apart and one of the bearings was really crunchy. they are sealed bearing so I pulled one of the seals out of it cleaned out the dried grease, relubed and it felt much better, not perfect but much better. So I pulled a seal on the other bearing and cleaned and lubed it. Reassembled the whole thing and it was back to making nice quiet power. I placed an order for a pair of replacement bearings, as I understand this is a temporary fix at best. But it has me back to making parts for now. Hopefully it will last through this project so I can take my time taking the RPC back apart and do a thorough cleaning and repair.
Back to the trunion.......
I took the RPC apart and one of the bearings was really crunchy. they are sealed bearing so I pulled one of the seals out of it cleaned out the dried grease, relubed and it felt much better, not perfect but much better. So I pulled a seal on the other bearing and cleaned and lubed it. Reassembled the whole thing and it was back to making nice quiet power. I placed an order for a pair of replacement bearings, as I understand this is a temporary fix at best. But it has me back to making parts for now. Hopefully it will last through this project so I can take my time taking the RPC back apart and do a thorough cleaning and repair.
Back to the trunion.......
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- Apr 29, 2019
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Finally back to making chips for actual parts for this project.
It took a long time for me to figure out a plan for making these Trunions and then design and make fixtures and tooling to get it done.
Here is one of the blocks mounted on the fixture that is mounted to the rotary table.
This fixture allowed me to machine the entire outside profile and put in the one slot that is at a weird angle. The RT has no problem dialing in a weird angle.
As is my MO, this was not without adventure. I found out that I could only use conventional milling as climb milling would snap both mounting bolts at the surface of the fixture and launch the part across the shop. The first time I had an aluminum locating pin the second time it was a steel pin, but that did not stop it from being launched. I finally ended up with an unknown grade of stainless for the 3/16 pin. I then only did very small cuts using only conventional milling. Slow but I got there. It was amazing the pile of chips that this generated. Lots of cleaning up to do.
Here is a pic of the 2 parts made along with the original part that I am copying. I still have to set up and do machining on 3 more sides. these remaining setups are nothing special it will just be clamping in the vice, Indicating in and make the needed cuts. Easy right?????
It took a long time for me to figure out a plan for making these Trunions and then design and make fixtures and tooling to get it done.
Here is one of the blocks mounted on the fixture that is mounted to the rotary table.
This fixture allowed me to machine the entire outside profile and put in the one slot that is at a weird angle. The RT has no problem dialing in a weird angle.
As is my MO, this was not without adventure. I found out that I could only use conventional milling as climb milling would snap both mounting bolts at the surface of the fixture and launch the part across the shop. The first time I had an aluminum locating pin the second time it was a steel pin, but that did not stop it from being launched. I finally ended up with an unknown grade of stainless for the 3/16 pin. I then only did very small cuts using only conventional milling. Slow but I got there. It was amazing the pile of chips that this generated. Lots of cleaning up to do.
Here is a pic of the 2 parts made along with the original part that I am copying. I still have to set up and do machining on 3 more sides. these remaining setups are nothing special it will just be clamping in the vice, Indicating in and make the needed cuts. Easy right?????
Last edited:
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I have discovered, Similar to your comment, that metal on a Lathe or Mill is like heavy cream. If you take a mixer to a 1/2 cup of heavy cream you'll end up with a quart of whipped cream. If I put a 2"x2"x2" chunk of metal on the mill I end up with a quart jar full of chips, a half gallon if on the lathe.....
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- Apr 29, 2019
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SO close. So very close. One trunion finished complete.
The other one, just one hole left to tap to #6-32 and it would also be finished complete, and yup the tap snapped off in the hole. Just about .010 of broken tap sticking out both ens of the holes, just to make it difficult to get anything started to remove the broken tap. Called it a night and will wait until tomorrow. Time to break out the 1/16 dia solid carbide end mills........
The other one, just one hole left to tap to #6-32 and it would also be finished complete, and yup the tap snapped off in the hole. Just about .010 of broken tap sticking out both ens of the holes, just to make it difficult to get anything started to remove the broken tap. Called it a night and will wait until tomorrow. Time to break out the 1/16 dia solid carbide end mills........
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- Apr 29, 2019
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Ha, saved it. However my poor 1/16 dia carbide end mill is no longer with us, may it rest in peace........
It was the 3/32 dia carbide end mill that was able to chew thru the tap and make it all gone. Ran a new tap through and the part was finished.
I have now started to build the first complete retract to begin testing.
Here are some pics of a completed trunion (left) along side the original (right).
In this one you can see the slot that was added for clearance to the motor drive shaft. Adding this slot was one of the driving reasons for going thru the effort to make this part.
It was the 3/32 dia carbide end mill that was able to chew thru the tap and make it all gone. Ran a new tap through and the part was finished.
I have now started to build the first complete retract to begin testing.
Here are some pics of a completed trunion (left) along side the original (right).
In this one you can see the slot that was added for clearance to the motor drive shaft. Adding this slot was one of the driving reasons for going thru the effort to make this part.
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