I just bought a previously flown Sig Kadet Mk II from my instructor and am installing the engine, radio, etc. I have a couple of questions.

1) Can anyone tell me where the CG should be on this plane?

2) I purchased a Hayes tank to replace the ancient tank that came with the plane. I've always (in my very limited experience) used Sullivan or Du-Bro tanks with the three hole stopper and brass tubes. The design of the Hayes with two of the three holes molded into the tank seems a lot simpler (no tubing to bend). Are there any problems or drawbacks to this design?

-Scott

Start with the CG at the front of the spar (1/3 inch forward of where you can feel the rear of the spar) and it will fly. You'll probably end up moving the CG back from there. At the rear of the spar to 1/2 inch behind the spar is where you usually end up liking how it performs.
I have no idea what the instructions say any more... I haven't read the instructions on a Kadet in 15 years.

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I never had a problem with a Hayes brand tank. I have seen knock-offs that have been problematic due to poorer quality. The design is fine.
'
The only ways to defuel this tank are through the klunk line or by inverting the aircraft. I never defuel any more... I just connect the muffler line to the carb line with a short piece of tupe or a fuel filter. No drips. You can leave fuel in a good quality tank for months.

Note that the way they ship, the lower of the molded in fuelu line nipples is sealed. If you want a 3-line fuel system you have to drill out the lower nipple.

Thank you, sir. I already drilled out the lower nipple. I picked up on that from the instructions. Sounds like it should work fine for me.

-Scott

I have the directions for the MKII at home. I'm just finishing mine up as well. I'll see what they have listed for the CG tonight.

Thanks, Griffin-

The one I bought looks like it has survived quite a few flights and done pretty well. I wish you the best with yours. From everything I've heard, its a great plane.

-Scott

C.G- 21-25% of the chord. Measure back from the leading edge.

2 5/8 from Leading Edge is front limit to 3 1/8 from leading edge rear limit

I have the instructions for a Kadet in my sweaty mitts right now. Here's what it says.
To balance at 27%of wing chord go 3 1/2 inches back from front of wing.
to balance at 30 % of wing chord, go 3 7/8 inches back.
to balance at 33% of wing chord, go back 4 1/4 inches back.
27% is best balance for beginners. 30 % is good middle of the road balance and 33% is recommended for more experienced fliers.
I hope I helped you.
Derrick

Thanks guys!

I use Hayes tanks whenever possible. I really like them. Never had a bit of trouble with one. Like you said simple. Remember the KISS principle- Keep it simple Stupid. I sometimes can be real stupid. So the simpler the better.

Mark Shuman