Hi Trevor,
Some of the lightest KR2's sit at about 520 lb, but that is with the Jabiru
engine that is some 50 lb lighter than all other engines in Kr's.
I have my empty C of G position way out the front limit by placing the engine
12 inches further forward than the 1834 VW engine I took out. I have to ballast
the aircraft aft if I fly it solo, otherwise it would be out the front limit.
But this allows either me and a load of baggage instead of ballast, or two up
and little baggage possible. C of G is the most important aspect of a KR
because the crew sit well aft of the C of G.
I've braced the parcel shelf, covered it in 3/32 3 ply sheet. It will hold 20
lb up to 6 G. Breakage of the parcel shelf could be nasty if heavy items break
through and fall to the back.
If you estimate your completed aircraft to be between 500-525lbs total, this is
possible with a Jabiru engine. If you fit any other engine and maintain the 520
lb, you will have built the lightest KR in the fleet. Mine does not have flaps
or a speed brake. I expect an honest figure below 600 lb would be doing well if
you have fitted either and any other engine than a Jabiru. It is annoying how
the weight just keeps building as you get close to completion.
The whole of the back of my KR is filled with white polystyrene foam for
flotation. Into it I cut a hole sufficient to fit my mountain bike wheels in
behind my seat which hinges open and have clothes and maps and sleeping bags
and teddy bears on the parcel shelf behind my head.
This is only possible because a heavy survival dingy is placed up by the rudder
pedals, the tent is forward of the spar also. What really makes all possible is
a baggage bay behind the engine in front of the firewall, where spares, tools,
oil and any other heavy item goes.
So if you have built light or don't care about the take off weight, you can
carry the kitchen sink, as long as its balanced out.
If I was you, I would build huge space in the back of you plane and try to get
the empty C of G as far forward as possible in order to be able to use the
space. The only way of changing empty C of G is after knowing the weight and C
of G of whatever engine you will use, you can change the length of your engine
frame. The engine frame is the last thing you should build in a KR.
Its similar to asking about how big to build the fuel tanks. You want to build
them as big as you can, you don't need to use all thevolume, but one day you
may want to so build it as big as possible.
If you know all this, I apologise, but other people might read this also and
need to know.
I'm not sure if it will work but below is a link to my facebook page showing
all I fit in to the plane and the rear fuselage space and how my mountain bike
comes apart to fit on the passengers seat in a canvas bag.
https://www.facebook.com/photo.php?fbid=406907709493483&set=pcb.406908502826737&type=3&theater
Cheers Colin.
