The craziness continues!
My continuing flirtation with Aviation:
I've purchased a 90% complete Mitchell U-2 Flying Wing!
(Which in Aviation math usually means, 90% is left to be done.)
Manufacturing a new Seat Mount
Evidently the original builder had issues with ingress and egress - it is a little hard to get in and out of this little plane. So he build a seat mount that had a HEAVY pneumatic lift system to raise and lower the seat so he could get in and out easier. That pump and cylinder had to go! Also, I couldn't use his seat position as my feet couldn't reach the rudder/air brake pedals comfortably. So I'm building a new seat mount.
|This is the builder's seat and seat mount on the back of the trailer when we arrived back home. I knew then that some changes were necessary - the combination weighed in at 11 lbs!|
|So we went out to the field and made measurements of the distance between my lap and mid-shoulder when sitting in the seat in a position that made it easy and comfortable for me to reach all of the controls. Here we have used the measurements to mark the table with blue tape. Then with me seating in the seat, we put blocks under his old mount until my lap and shoulders were in the correct relationship.|
|Here we were measuring the new angle needed for the seat mount. Sorry I only took one picture and it turned out very blurry!|
|Once again we cut, glued and stacked foam insulation to make a plug for the new seat mount.|
|Next we cut out the plug
and shaped it to the corrected angle. At this point we had to make
the 60 mile round trip to the field just to see if the plug would fit on
the seat's support rails. While it is frustrating to drive that far
make a 1 minute measurement, it is good that we did because our plug was
an 1/8 of an inch too wide for the rails!
Here you can see the difference in angles for the seat on a level surface, vs. the builder's mount and finally vs. the angle that I require for my mount.
|After we cut out the plug
and measured it I began to have some serious second thoughts about the strength
of my original approach. So I decided to take a different
approach and fabricate the mount out of individually engineered pieces.
First I did the calculations for the platform on which the the seat will rest - here it has just come out of the vacuum bag. That 1/2 in thick platform is built to hold a 200# pilot at 8 gees - not that I weigh 200#s nor will I ever intentionally ever attempt an 8 g maneuver!
|The three components after all have been vacuum bagged.|
|Assembled and epoxied.|
|Checking it out before
finishing - the edges of the carbon fiber mount all still need to be
closed and sealed as well as hard points installed for the bolts.
This mount can not be used. Originally the builder anchored his seat to the skids and I was going to follow his approach but recently I have discovered there is major damage to the skids. Also a review of the drawing clearly indicates the seat should be mounted directly to the spar (not on the skids) so I will have to come up with another approach which is OK because I wasn't totally satisfied with this seat mount anyway.