Recent content by Marc Bourget


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  1. M

    Good bandsaw for making forms

    Sometimes "blade walk" is caused by too narrow a blade forced to accept too much pressure. Agree on the bi-metal. I picked up a 16" Delta ML and a 36" Delta (forget mod #) and learned the narrow blade lesson real quick. Saws came with 5-6 boxes of blade material. I gave up on them and only...
  2. M

    aluminum rivets

    There are two ways, actual annealing and the second, frequently called annealing, is technically bringing the material to "W" Temper - which takes more than 500 deg F. You really want to have the rivets as soft as possible. Some may recall my addressing this point in my sheet metal forums...
  3. M

    How Hot Is Too Hot?

    Trapped air in a liquid cooling system has been thoroughly researched and worked out. As Wsimpso1 said above (and referenced by me, earlier) you have to remove the air - or, avoid trapping air. I'll repeat and re-emphasize, you have to work diligently to ensure that all instances of conditions...
  4. M

    How Hot Is Too Hot?

    This is one of the posts I closed with the comment "I may have missed". As to increasing the size radiator hoses, anything that restricts flow can contribute to formation of bubbles. My notes are packed from a move, but we're talking, IIRC, inches of H2O Delta P. My "guy" gave me a...
  5. M

    How Hot Is Too Hot?

    Both WSimpson and TFF raised good points that deserve greater development. Overall, you have (not only) to ensure that the heads remain wetted, but you also have to (what I say in my cooling lectures) - "Turn off the Bubble Machine." Points to keep in mind, it only takes a minor amount of...
  6. M

    Wing to Fuselage Placement

    The goal is to disturb the air you're passing thru as little and as low-rate of disturbance as possible. Further explanation takes books. Understanding the previous point will help you "grok" the books. Onward and upward.
  7. M

    Bolt holes, burr and fatigue life effects

    Checked out the report, only to notice it is 295 pages long.
  8. M

    Liquid cooling

    It may have been cold, but recognize that his intent was to get the man to "warm up to the subject." :)
  9. M

    Bolt holes, burr and fatigue life effects

    Probably because you're not "grokking" that a drill penetrates by fracturing or tearing the metal (microlevel) Deburring sufficient to remove the "tear" doesn't appreciably decrease the bearing area. The metal is disturbed (moves) with loading. The tiny "cracks" have an opportunity to...
  10. M

    Thorp T211 corrugated wing skins

    It was interesting reading the speculation on forming the wing skin. I was mentored by John for 15 plus years and we talked about the Scooter frequently as various buyers for the Scooter Project approached John because the Type Cert went with the project. Dealing with such issues was...
  11. M

    How does aircraft spruce roll up aluminum sheets

    If you're rolling a sheet of aluminum, the first thing to do is cut about an 8" wide by 4' piece of cardboard, fold it in half lengthwise and put that on the leading edge of the end you're trying to fold. Avoids some nasty scratches, it does.
  12. M

    How To Clean Out Pitot Tube...Looking For Advice

    OTOH, my C-185 checkout was notable for the requirement that I do a full flap go around and return to land without the airspeed coming off the peg. Some diabolical instructors lay awake at night thinking up such things. Does teach you to "fly the wing" however! FWIW
  13. M

    After market liquid cylinders for Lycoming engines

    Don't remember the exact source or the specifics but my memory trigger reminds me that the extended low power settings were the reason for the liquid cooled head in Rutan's design. Take with the usual oz of salt! :^)
  14. M

    Gurney or traditional?

    Billski said: "If your rudder trailing edge is too thin (many metal control surfaces are), : How's that fit with the defined knife-edge trailing edge and the "Kutta Condition"? :^) [I've opened this thread up with that query! - :^) ]
  15. M

    Repairing Small Ding in Engine Mount

    By "blendout" I understand this to mean 20x the depth of the "damage." Hypothetically, a 1/4" depth would witness a 5" taper up to the regular OD of the tube. FWIW