SE5 KK-OZ1320

 

While I'm waiting for some roundels for the wings I made up a tail from 1/16th scrap (reserve stock) to see the difference between that & the sheet tail.
The sheet tail weighs 4.74gm, the fabricated 2.5gm.
This reduces the balance weight neccessary from 17.25gm to 11.50gm & the total weight of the model from 70.59gm to 62.50gm, a difference of 8gm, a reduction of 11%. Qite a reduction.

 

 
I've now got it painted and assembled apart from covering the underside of the fuselage.
The nose button is too small so the back of the propellor fouls the nose block so I've got to put a spacer in or a bigger nose button.
I'm having trouble getting the windscreen to stay put, it sticks but keeps getting knocked off & then is a bugger to find.

Putting 12g of lead on the noseblock balances it at mid-point of the upper wing.
Without the balance weight the model weighs 53g.

The balanced VMC Sopwith Triplane I built weighs 49g. The SE5 has sheet sides all the way to the tail & I had to use sixteenth sheet to cover the nose. whereas the ST only has sheet to the TEs of the wings plus there are cut-outs in what there is & I don't remember having to use that much lead.

 The roundels on the wings are the vinyl ones I bought whereas those on the fuselage & the flashes on the tail I printed out on self-adhesive labelling.
I didn't think the self-printed ones would stick to the curved surface of the wings, the vinyl ones even needed a little bit of extra help.
I now have a nice M on the centre of the upper wings.
 

A very nice looking model.  Look forward to hearing about what it is like in the air.  At that weight and size that would be a calm day....

I see you've set the CoG at 50% of the top wing, how far back is the leading edge of the lower wing in terms of chord %?

CG at 50% of the top wing certainly sounds a bit fr back to me for what is a conventional biplane layout unless there is big wing stagger. Would be a bit different if it was a "contest" type plane with a "lifting" tail.

In my earlier calculations I worked out 11.5 gm would balance the CG, I just happenned to have a 12g piece of lead so I balanced that on the nose & it gave a CG at mid-point on the upper wing which is a starting point. Until I can test-glide it that's as far as I can go.
Somewhere on the web I read that with biplanes with staggered equal wings the CG should be midway between the CG positions of each wing.
I mentioned the problem that the propellor was fouling the nose block, I put a bigger button on & it still fouled. Closer inspection revealed that one of the prop blades was wider than the other & projected further back. It was out of one of the KK kits I bought.
The weather at the moment is not fit for a dog to be out in, never mind a model plane.
Plus a couple of weeks ago I did my back in so I'm limited at the moment, even Aldi is hard work especially trying to reach stuff on the bottom shelf!

The top shelf is even worse, unless you carry a stepladder with you!