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  1. P

    piston skirt relief

    Yes, my initial plan was to use my 5C collet block. But in order to have the wrist pin hole exposed for alignment, it would only grip top crown portion of the piston. The V blocks have 4 lines of contact & the tape provides some protection & grip. But its concentrated stress so a fixture is a...
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    piston skirt relief

    Thanks Jos. Yes I understand the clearance issue. What I was referring to was (avoiding) lapping the piston to its correct finished diameter in order to correct any eccentricity or stress relief resultant from milling the non-symmetrical pocket, skirt window etc. So for example if the bore is...
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    piston skirt relief

    Ah, totally forgot about counterweight clearance & the more compact rod assembly on the typical single cylinder RC-4S. Thanks for the comments.
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    piston skirt relief

    The other thing I wanted to mention is the commercial pistons are typically cast or forged aluminum as opposed to my bar stock. When I milled my tester piston, I detected about 0.0005" of deviation to skirt diameter. This could have been stress relief or could have been from V-block clamping...
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    piston skirt relief

    I'm just about to make the pistons for my 5-cylinder radial. The plans call for a cylindrical profile, the bottom skirt portion is shelled out and a further deeper milled slot for the link rod. I noticed the Edwards radial is much the same. But I've noticed almost every RC 4-stroke engine I've...
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    Spark plug boots

    Hi Steve. I'm not too sure what system you will be using, but generally the suppliers of RTV & flexible urethane also usually provide color tint additives to turn it opaque. A little goes a long way, Its generally advisable to use their systems so you don't have any curing surprises. For...
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    HMEM will be having a software update later today

    Thanks Cogsy, your steps seem to have worked for me. I've had this same issue before so I took some screen grabs for future reference or if it helps anyone else here. Note, you may have to be logged off the site while doing this in the Chrome settings tab, but not 100% sure.
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    HMEM will be having a software update later today

    I'm still having to log in every time. In Chrome is there a way to clear cookies to (this) specific site only? Otherwise looks like all settings would have to be reset. I thought in the past I encountered another settings page where each app was identified, but maybe that was auto-fill in settings?
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    update

    same here, needs log in every time despite check box toggled.
  10. P

    270 Offy

    Been looking forward to these parts! What kind of drill is that? (0.137" x 5" deep)
  11. P

    wrist pin design

    There are a few instances of 'dowel' for various similar shafts, but nothing I see for the wrist pins. Assumed it was just me. I thought those Edwards drawings were bulletproof by now.
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    wrist pin design

    tornitore45, I had a quick look at the Edwards drawings prior to pondering my decision. Maybe I missed but what did the stock design call for? I think I saw hardened dowel pins but maybe that was for the bottom ends in the master rod? Are you going to harden yours? WOB, thanks for another data...
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    wrist pin design

    I'm working on the wrist pins for my 5-cyl radial radial (24mm bore x 22mm stroke). The plans call for 5mm diameter 'hardened' steel & solid cross section through the length. No provisions were made for end pads which has me a bit concerned. The liner is cast iron & the link rods are 7075...
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    Metal annular ring growth at elevated temperature

    Just curious, any Edwards 5-cyl builders out there? That design is quite similar to my radial in this regard. The Edwards plans specify a min/max for the cylinder ID and liner OD. Going by these numbers the possible interference can range from 0.0000" to 0.0015". What I'm not sure of is the...
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    Metal annular ring growth at elevated temperature

    Can anyone guide me to the proper formula/methodology to evaluate the diameter increase of say a liner or cylinder under elevated temperature? I first assumed I could just multiply any dimension such as the bore or OD by the thermal coefficient to get the new dimension at new temperature. Now...
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    270 Offy

    Just curious what makes 32 AWG wire more desirable in this application?
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    270 Offy

    30 & 32 AWG here in various flavors. He is my go-to crack dealer for good quality plugs, pins, crimp tool...). http://www.hansenhobbies.com/products/connectors/wire/servo_ec/ Check his write-ups on RC wires, they are not all created equal. Strangely no AWG specified but I can attest to good...
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    270 Offy

    I've had to marry quite a few awkward wiring harnesses together for RC work. For things that need to be soldered, my go to method is a small plate of something heat resistant like glass & if necessary 'shim' supports from arborite scrap. And Kapton tape. You can usually get everything...
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    Demon V8 (multiplied 1.5)

    Fantastic! Enjoyed your build & the video of it running.
  20. P

    Four stroke three cylinder radial of my own design

    Very impressive and unique. Cant wait to hear it running. What influenced the design of the piston? It has a profiles dome crown & what appears to be wider ring groove. Just curious.
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