Aileron pulley and flap torque tubes

[bestbearhawk1231]

Hi again, a couple quick questions, first off, what is the difference between the an210-4a and an210-4b (ms24566-4a and ms24566-4b) pulleys? The plans call for the -4a pulleys but ACS only has the -4b pulleys listed on their website. Are these two types of pulleys interchangeable and if so what are the differences?

Second question, can the 6' flap torque tubes be two pieces spliced together so save on shipping to do they need to be one piece? I am ordering a sheet of aluminum and would like to save on shipping by cutting down the torque tubes so they fit into the same box as the aluminum sheet.
Thanks, Joe

[alaskabearhawk]

From the A/S site: "AN210A & AN210B (MS24566) Anti-Friction Bearing Control Pulley with phenolic body and ball bearing with seal. The AN210A pulleys are dimensionally the same as the B pulleys but have metal-shielded bearings rather than removable composition-seal type bearings."

http://www.mcfarlaneaviation.com/pdfDocuments/McFarlane%20Pulley%20Dimensions%20and%20Supersedures.pdf

As far as the torque tubes go, in my thinking "torque tube" means one piece. There is a lot going on in the flap drive system. That flap is HUGE and any misalignment or weak weld will show up immediately, usually at precisely the wrong time. I think there are better places to save money.

[bestbearhawk1231]

Thanks for the response Paul, I was planning on doing a 30 degree angle splice with a support tube inside and rosette welds holding the support tube in place. It should be as strong or stronger than the original tubing, that being said, I ended up adding a sheet of aluminum to the order so I was going to get bent over either way on shipping and ordered the torque tubes one piece.

As far as the pulleys go, what do they mean by a "composition" seal bearing? Is it a piece of felt or fiber material that holds the oil in place and dirt out?

[alaskabearhawk]

The splice method is good, it's just quite a bit of work and demands accuracy. The real question is if the time and effort that you are going to expend to join the tubing going to offset the additional shipping cost. If you are going to save 10 bucks, you need to value your time more!

I spoke with Ralmark and they said all their pulleys are MS24566 spec. All their B series pulleys have the metal-shielded bearings. http://www.ralmark.com/ms24566.html The -4b has a KP4K bearing and lubed to milspec. http://www.ralmark.com/bearing.html The composition seal would just be some type rubber seal over the bearing using standard aviation grease.

[bestbearhawk1231]

Thanks for the pulley information. As far as the splice goes... it isn't that I don't value my time, I am young and on a shoe string budget so I am trying to do things as economically as possible while building an airworthy aircraft to the best of my ability. Lets face it, 10 bucks is 10 bucks although the difference was more than that when the ACS website did their shipping deal. As I understood the shipping through ups, 6' would have become oversize and the difference in shipping would have been substantial. After I added the sheet of aluminum to the order the shipping difference became a wash so I went full length. Unless ACS didn't follow the cut instructions, I will not be splicing.