Thursday, April 04, 2019

Stick Chair

I may be winning the battle with Desert Bloom but I'm sure the war is lost. Whatever, I'm back in the shop for a little bit the last couple of days.

This morning I cleaned up the jig sawn leg blanks:

It was quick work, a couple or three passes on each facet did the job.

Not so quick work will be cleaning up the seat blank. The bandsaw did a good job getting close to the line, the rest will be like that movie where John Candy was trying to go home for Christmas. Only instead of planes and trains it will be planes, spokeshaves, drawknives, chisels, and whatever else I can find to cut and smooth the edge.

Once the edges are cleaned up I'll decide which side will be the bottom and mark out the mortise locations and sight lines before beveling the bottom edges.

After beveling the bottom it will be time to drill and ream the seat mortises, give the seat a slight saddle, the Adze, scorp, travisher, and scrapers will join the fun.  Then turn the leg tenons and fit 'em to the mortises and before you know it this sucker will be a chair. The only real question remaining is arm or no arm and if the decision is to have arms do I add a comb.



  1. I think of Arizona as the place to go if you have allergies but I looked up desert bloom and now understand. I guess the desert plants really jump on it when it rains more than normal. Hope you feel better soon.

  2. By the way, decades ago I was a low time private pilot. I have been closely following the 737 Max situation and am frankly astounded as what the Ethiopian pilots faced. This MCAS system takes over due to a faulty angle of attack sensor (single point of failure) at low altitude right after takeoff. The plane accelerates rapidly, after a short time, the pilots turn out the automatic trim system and attempt to manually trim the aircraft (with a wheel and cable on a 737!!!) but they are physically unable to do it. They unfortunately turned the trim switches back on and MCAS crashes the plane. OMG! I suppose a 172 pilot just can't relate but this blows my mind.

    1. Andy,

      Most of the time Spring allergies don't slow me down, maybe a runny nose and a sneeze or two but this year has been different.

      Most modern jets have what is known as a stall fence or barrier because many are unrecoverable from a full stall. Best I can tell the MCAS is not part of that system. If I understand it correctly the MCAS is part of an artificial "feel" system that is only active with the autopilot off. It is there to make the aircraft feel "correct" as the airspeed changes. To certify an aircraft control force has to change per set standards as airspeed changes. As an example most jets can not meet this feel standard at high Mach speeds. To certify the aircraft the manufacturer can do several things. Install a "Mach Trim" system to trim the nose up as airspeed increases above a certain Mach number. Lower the MMO so the aircraft doesn't need a Mach Trim system or have a dual MMO with a lower MMO for flight without the autopilot engaged. Autopilots do not need the artificial feel, they are better pilots than us humans :-).

      The MCAS system, if I read it correctly, is a "Mach Trim" type system but at the low end of the airspeed flight envelope. It is there to give the pilots control forces that "feel right" and is disengaged when the autopilot is engaged.

      The other thing about the MCAS system, when working as designed, has both a very limited range and a slow speed. The max range of elevator movement of the MCAS is 2.5 degrees and it takes almost 10 seconds to move the elevator that far.

      I'm having a hard time seeing the MCAS as the cause. It could be but 2.5 degrees of movement ain't much and even if it exceeded that limit it will only move the elevator at 0.27 degrees per second. It will be interesting to find the cause.

      BTW, a runaway nose down trim could do the job. If that was the problem then it should show on the Flight Data recorder. A tail plane stall would cause a sharp nose down pitch but how that could happen is problematic.

      In other words I haven't a clue.