KF 4-1200 W&B Comparison

[dholly 718]

Well, call me curious or just plain nosey, but was wondering how other 4-1200's with 912ul FWF weigh out.

Builder of my 4-1200 did two prior W&B. First one when newly built on bungee gear w/ solid Maule TW (600lbs. empty), second done with Grove main gear, upgraded 2-leaf tailspring from Kitfox and a few other geegaw add-ons (668lbs.). I added 21-8.00x6 tires and a 3-leaf tailspring, but removed the solid Maule TW in favor of a smaller, lighter Aviation Products Inc. TW, so I really wanted (needed) to do a new weigh-in and W&B calculations.

Finally was able to check it off the to-do list this past weekend. Since I only have a half-hanger (gotta love those folding wings), we had to do this out on the ramp in a bit of wind so it probably isn't exactly perfect. Close enough for govmint work though, as the saying goes. So here are my results:

Left Main = 294lbs.

Right Main = 295lbs.

Tail Wheel = 78lbs.

Empty weight = 667lbs.

CG = 13.07"

A quick calc looks like (2) 200lb guys w/ 20gals fuel and lunch in the sack would be well within the envelope and under MTOW. In fact, if we did this right, it would appear you cannot possibly load the aircraft outside the Fwd or Aft CG in any way without exceeding the 1200lb. Gross Weight Limitation. Actually putting heavy pilots in the Aircraft moves the CG forward. Weight above the 40lb. limitation in the baggage sack is the only way to get even close to an Aft CG situation. Great design for an aircraft!

[1avidflyer 1983]

Doug, Maybe some day I'll finish my Kitfox 4 and will be able to give you a real answer, but what I've read and been told is that if you get the plane built and it weighs only 600 lbs, with a 912, you did pretty good. Not impossible by any means, but you have to be careful what you put in the plane. I'm trying to end up as light as I can, time will tell I guess. Maybe if I didn't keep having to rebuild bent up planes, I'd have more time to work on the Fox. Take care, Jim Chuk

Well, call me curious or just plain nosey, but was wondering how other 4-1200's with 912ul FWF weigh out.

Builder of my 4-1200 did two prior W&B. First one when newly built on bungee gear w/ solid Maule TW (600lbs. empty), second done with Grove main gear, upgraded 2-leaf tailspring from Kitfox and a few other geegaw add-ons (668lbs.). I added 21-8.00x6 tires and a 3-leaf tailspring, but removed the solid Maule TW in favor of a smaller, lighter Aviation Products Inc. TW, so I really wanted (needed) to do a new weigh-in and W&B calculations.

Finally was able to check it off the to-do list this past weekend. Since I only have a half-hanger (gotta love those folding wings), we had to do this out on the ramp in a bit of wind so it probably isn't exactly perfect. Close enough for govmint work though, as the saying goes. So here are my results:

Left Main = 294lbs.

Right Main = 295lbs.

Tail Wheel = 78lbs.

Empty weight = 667lbs.

CG = 13.07"

A quick calc looks like (2) 200lb guys w/ 20gals fuel and lunch in the sack would be well within the envelope and under MTOW. In fact, if we did this right, it would appear you cannot possibly load the aircraft outside the Fwd or Aft CG in any way without exceeding the 1200lb. Gross Weight Limitation. Actually putting heavy pilots in the Aircraft moves the CG forward. Weight above the 40lb. limitation in the baggage sack is the only way to get even close to an Aft CG situation. Great design for an aircraft!

[EDMO 1078]

Well, call me curious or just plain nosey, but was wondering how other 4-1200's with 912ul FWF weigh out.

Builder of my 4-1200 did two prior W&B. First one when newly built on bungee gear w/ solid Maule TW (600lbs. empty), second done with Grove main gear, upgraded 2-leaf tailspring from Kitfox and a few other geegaw add-ons (668lbs.). I added 21-8.00x6 tires and a 3-leaf tailspring, but removed the solid Maule TW in favor of a smaller, lighter Aviation Products Inc. TW, so I really wanted (needed) to do a new weigh-in and W&B calculations.

Finally was able to check it off the to-do list this past weekend. Since I only have a half-hanger (gotta love those folding wings), we had to do this out on the ramp in a bit of wind so it probably isn't exactly perfect. Close enough for govmint work though, as the saying goes. So here are my results:

Left Main = 294lbs.

Right Main = 295lbs.

Tail Wheel = 78lbs.

Empty weight = 667lbs.

CG = 13.07"

A quick calc looks like (2) 200lb guys w/ 20gals fuel and lunch in the sack would be well within the envelope and under MTOW. In fact, if we did this right, it would appear you cannot possibly load the aircraft outside the Fwd or Aft CG in any way without exceeding the 1200lb. Gross Weight Limitation. Actually putting heavy pilots in the Aircraft moves the CG forward. Weight above the 40lb. limitation in the baggage sack is the only way to get even close to an Aft CG situation. Great design for an aircraft!

Thought FAA "certified" pilots and passengers could only weigh 170 lbs each for W&B? You could haul 10 more gallons of fuel at those weights!

ED in MO

Edited 12 Mar 2013 by Ed In Missouri

[dholly 718]

Ed- the feds fail to account for the layers of body fat necessary to weather the upstate NY winters. Translation: I eat out too often.

Jim, I'll buy breakfast if you keep it under 600lbs. I've only heard of a few and no one offered any proof. I was shocked to see 600lbs. on the initial W&B sent to the FAA for mine. I have to question it as the subsequent changes should not have added over 60lbs+, IMHO.

[EDMO 1078]

Ed- the feds fail to account for the layers of body fat necessary to weather the upstate NY winters. Translation: I eat out too often. :)/>/>/>/>

We all eat out too often - Engineering theory 101: The cold air that produces the need for more insulation also is denser and the lift of the wings is enhanced to make up the difference.

(Unless your scales are "air density compensating",Cheating on scales is necessary)! Just ask a woman!

Ed in MO

Edited 12 Mar 2013 by Ed In Missouri