Making light and strong carbon bellcranks

This video shows in detail how very light but strong bellcranks can be made. Also, it shows how the bearings are installed including prevention of galvanic corrosion.
Some time ago, I explained galvanic corrosion in more detail and how to check if a part might suffer of it:
• How to prevent galvani...
Enjoy!

[@adrianharrison5208]

Thanks for the video, those bellcranks look amazing!

[@ladraode9dedos409]

F1 construction standard! Very well done!

[@billtrue3017]

You are one very talented guy

[@davidepodeschi243]

Very good Andres

[@dekutree64]

Thank you! I was wondering how you actually get the glass fabric between the carbon and bearing, but it hadn't occurred to me to use a thin sheet of glass that's already been hardened with epoxy so it's easy to work with.

[@FirstLast-tx3yj]

Amazing

[@carbonarne675]

Das compoflex zeuch ist echt geil, nutze ich auch

[@andreschavarria1450]

Geiles Zeuch, nur wenn viel Krümmung da ist, muss man schon etwas kämpfen. Das gilt aber für anderes Zeuch auch …

[@diegoandresbustamante2742]

I would have made them in aluminum. I envy your patience doing those in CF!!

[@ladraode9dedos409]

Hello Andrés, thank you for your time for recording and editing all those videos and sharing your skills here on KZbin. Could you please tell us what is this vacuum pump you use on this video?

[@kamildarek3425]

Andre Demetrio looks like frige compresor

[@ladraode9dedos409]

@@kamildarek3425 I meant the vacuum switch... Thank you anyway!

[@Juststartbike]

muy buenas piezas, perfectas, la LG 735 Aero va muy bien.

[@SuperYellowsubmarin]

Splendid, but could it be possibly worth the work ?!

[@LindyDesignLab]

Did the carbon cloth have something on it to reduce fraying before you cut it, or were you just very careful not to unravel it while adding resin?

[@andreschavarria1450]

Yes, we used some spray adhesive to reduce fray. Some companies sell ant-fray sprays, but it's probaly nothing else than a usual spray adhesive for vacuum resin infusion. A thin mist is enough to prevent fray. Adhesives for vacuum infusion are compatible to epoxy resins and are safe to use in layups.

[@LindyDesignLab]

@@andreschavarria1450 good to know. Thanks for the response.

[@ultralinx200]

@@LindyDesignLab I've seen you already have a web-lock cloth?!

[@MW34funxD]

Hallo, kann ich dich fragen welche CNC-Fräse du verwendest? Und falls es ein Eigenbau ist, was für eine Frässpindel verbaut wurde.

[@andreschavarria1450]

Hallo Raphael, es war ein AL-Bausatz von Sorotec. Fräspindel ist eine übliche 2-3 kW Chinaspindel.

[@MW34funxD]

@@andreschavarria1450 Danke für die schnelle Antwort

[@d3xterown]

Are there anny plans of what you're building?

[@andreschavarria1450]

We have a build blog: hortenmicrolight.wordpress.com/ We also post pictures regularly on FB and Insta: instagram.com/hortenmicrolight facebook.com/hortenmicrolight

[@dejayrezme8617]

This seems like an insane amount of work to save a few grams though haha. I assume this is for your nurflügler. Thanks for the video!

[@andreschavarria1450]

Whatever it takes to fulfill the requiered empty weight ;-) A few grams times 10 or more bellcranks makes a noticeable difference …

[@Hobbymann]

Hallo,wo kann mann diese Compoflex kaufen?

[@andreschavarria1450]

Ich kaufe meins bei GRM Systems in der Tschechischen Republik und bei Mühlmeier Composites in Deutschland. Für overseas kenne ich keine Quelle.

[@d3xterown]

When are you planning to fly this?

[@andreschavarria1450]

As soon as possible, but It will take some years to get finished. Lots of details …

[@adrianharrison5208]

what happens if a bearing needs to be changed?

[@andreschavarria1450]

Well honestly, I don't think that the bearings will ever have to be changed. These are maintenance free spherical bearings subjected to forces way bellow their load rating. Also the motion is very slow (control of an airplane). So in case the bearings are damaged, the bellcrank should be replaced too. Anyway, the mounting plates of the bearings are full carbon laminates with a hardness higher than, for example, high strength aluminium. Thus, very similar to a usual metall bellcrank, the bearings could be carefully pressed out of the mounting. I would suggest using wood or something similar as a support to prevent punctual loads.

[@adrianharrison5208]

@@andreschavarria1450 ok thanks all good things to know.. I forgot that this is for aplane and yes the whole thing would be replaced

[@perfectiom3718]

Speaking of strength, how much layer of carbon fiber you put on one side of the part?

[@andreschavarria1450]

@@perfectiom3718 That depends on the needed strength. Already one layer of 240 g/m² in +-45° orientation is usually more than enough. For higher loads, the unidirectional caps need to be adapted too.

[@ultralinx200]

I've see that compressor at my freezer, is it really is?

[@andreschavarria1450]

Yes, old freezer compressors can be used as simple vacuum pumps. They can reach good values below 100 mbar. Only their volume flow is somewhat low, but still fine if you have a consitent vacuum setup.

[@Alhussainba]

@@andreschavarria1450 100mbar, isn't that like 10kPa ? cheap house vacuum cleaners are around 20kPa, wouldn't that be better? I read online that appropriate pressure should be between 30-50kPa. What do you think?

[@andreschavarria1450]

@@Alhussainba The adequate pressure depends on the application. Sometimes less is better, for example, when the core is very soft, and sometimes higher is better, for example, when a high fiber volume fraction is wanted. In this case 100 mbar or 10 kPa are fine, because the pvc foam core is stiff and strong, and we want to achieve a high fiber volume fraction. You could do it with 20 kPa or even less. The piece will probably weight somewhat more then. 30 to 50 kPa is somewhat low to achieve a laminate with a high fiber volume fraction. Maybe the data you found was for very soft cores, which do not allow higher pressure differences. Though vacuum cleaners are cheaper, they are very often not made to run for 12 or more hours in a piece. A vacuum cleaner able to run continuously is probably even more expensive than a cheap vacuum pump, such as Thomas, etc.

[@Alhussainba]

@@andreschavarria1450 Really clear answer, thanks for taking the time to educate and help people for free.