G'day Crew,

Just finished building my ARF kit. Took 3 days in total. All in all a very very nice kit, used 99% of the supplied hardware. Hardware I replaced included the engine mount bolts (Hex head) and so far 1 clevis (metal). The instructions are excellent!

I buggered up the rudder position, I placed the vertical fin too far forward by about 3mm and the 5 min epoxy had dried before I realised. Unfortunately this left about a 2mm gap between the fin and rudder, which I sealed with tape at this stage, to prevent flutter.

This was the only flaw, damn, and I am kicking myself for not being more careful.

Now to my problem. To balance I need to know the distance back from the leading edge, the manual states:

2-15/16" to 3 1/2"

Can someone PLEASE convert the measurements to millimetres.

SIG has a customer for life, in fact I am awaiting a Sig Rascal 40 kit to come in from the States via shipping container.[&o]

A few ideas..........

Whenever you have a situation like this again, where you've placed the fin "out of reach" by the rudder, if the rear of the fin is square, just glue a strip of balsa to it to fill the gap. A strip of Ultracote to match the fin colors is easy to iron on for fuel proofing. Then hinge the rudder on and you're good to go.

If you've used the CA hinges, and got a 2mm gap, the hinging is going to be somewhat vague, even if you've sealed the air gap. It might be worth fixing the gap. CA hinges rely on being supported by wood everywhere except their bend-line. Truth is, your fix will fly but would be better fixed. And btw, sealing big hinge gaps does more than prevent flutter and isn't really done for flutter most times. And with a loose hinge like unsupported CA hinges would give, that'd contribute way more to flutter than sealing the hinge line would do.

Will your fix work? Probably. It's probably "good enough". Our models will fly with all manner of things done to them.


25.4mm = 1" so.........
2.94 X 25.4 = 75mm
3.5 X 25.4 = 89mm

An even easier way to set the CG is to balance right on the main wing spar with the front of the spar being the front end of the CG range and the back end of the spar being the back end of the CG range. You can feel it pretty easily and is the perfect spot for this plane. It will then require just a little bit of down elevator when inverted.

Do not worry about getting the CG just right, this plane is very forgiving. I am actually way back of the recommended rear most CG and it still flies very well and is not everly sensitive plus now it will hover and torque roll not well but it does do it, tumble and I even had it pull the nose up into a vertical climb from a Knife Edge and it's bone stock using a Saito 91 and an APC 15X6

I have the same issues with measurements, just the opposit way. I get the manuals with the measurement in MM so I have to convert to inches.

This site does the conversions for me. You put in what measurement you have, select the type you want and there it is.

http://www.onlineconversion.com/length_common.htm

I keep it bookmarked for quick reference.