A Stitts Skycoupe Restoration Project

The Stitts Skycoupe is also known as Stitts SA7 D

Friday, December 16, 2011

Weight Watching

This session was a first stab at weight & balance of the Skycoupe. Although there were missing elements, notably the fuselage fabric and paint for the whole plane, we got a good idea of where we stand in regard of the Light Sport rule of max weight.
 Here are pictures on how this session wound down:

First put the wings on (Terry had to fabricate temporary wing struts - fabricating time: 10 minutes!) :




Then look at the scales:
Main Left:

 Front:

 Main Right:

Hardly visible here, the tail feathers were also installed and counted (I don't mean the tail feathers of the dog!):

This is Terry's take on the weight status:

The Skycoupe had a total weight of #428 pound using the wing attach points as the horizontal datum

Left Main #190
Right Main #208
Nose #30
Total  #428

This was with unusable fuel, full oil, with no battery, ailerons, struts, avionics, instruments, or panel.
I figured a quick conservative finished weight with 2 standard adults, 12 gallons of fuel, and all the missing parts and coverings/coatings etc. of 1288 pounds. Keep in mind LSA max gross is 1320 Pounds.
Thanks to Mike, Martha, Mike son Mark, JP, and Jim Cronin

2 comments:

  1. I have been trying to find information about the sa 7 skycoupe and am finding very little, the certified 9 gives a gross weight of about 1575 lbs and it looks like yours will come out with a useable capacity at LSA max. What I really want to know is the cabin size. Though planes fit people differently the most useful measurement is fuselage width, can you give me a measurement across the seat on the inside of the airframe?

    ReplyDelete
  2. Trackwelder, while weighing our Skycoupe, we goofed - no one watched as the scale under the nose gear spun through 360 degrees - twice - before showing the final weight of 30 pounds. It should have been obvious to us, and we're all having great fun kidding the guys who did the initial weighing. It is still too early to tell what our plane will weigh, but it is not looking likely that we'll make the LSA gross limit with two pilots on board. The certified SA-9 is heavier. Other SA-7s we're aware of come in between 1260 - 1500 lbs, it depends a great deal on the engine used. The light planes used a C85 as in Ray's prototype, the heavy ones used Lycoming O-290s or O-320s. We have an O-290. If one built the plane from scratch and paid close attention to weight, and used a light engine (Rotax?) it would probably be possible to keep it under 1320 lbs. We understand that the structure is overdesigned and quite strong, but that adds weight of course. Do you intent to build an SA-7? Contact me at kmisegades@bellsouth.net if you want to know more about our project. We plan to fly it to Oshkosh this summer.

    ReplyDelete