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Old Jan 24, 2013, 11:43 AM
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Failure is not an option
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Quote:
Originally Posted by heli_madken View Post
I designed a shelf for weight up at the front of the nose so its easy to get lead in there, it took 1.08Kg (2lb 6oz) to achieve the 90mm CG

So with the estimated finished weight now at 9.5kg wing loading has increaseed to 35.4 oz/sq.ft with pretty much the same stall speed as before 29.5mph

Any opinions?
Ken - in my opinion a WL of 35 on a model of that size will be no problem. Wing volume is the key and as long as you have washout it should be a stable floater. I would run the cube numbers again but they probably won't change much, thus proving my point. I also agree with the comments about flying it more nose heavy than it should be according to the calculations and 25% MAC on a semi symmetrical wing seems about right. If it is sluggish on the controls and wants to come down right away when you cut the power, you can move it back from there.
Rob
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Old Jan 24, 2013, 12:06 PM
eye4wings is online now
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You know, given a wing loading that high it might be as well to remove the gun for the first flight or two until you see how well it flies and have a better idea how much extra weight the wings can carry.

I'm sure the test flights of the full size would have been made without armament installed!

If you have plenty in hand then you can add the gun back without undue concern. Would that be possible?
Old Jan 24, 2013, 12:09 PM
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The wing loading isn't terrible for a plane of that size. If its performance is lacking after its properly trimmed you can think about rebuilding the tail section using the lightest possible methods. A saving of an ounce or two would save probably 5 or 6 times that much lead in the nose.
Old Jan 24, 2013, 02:07 PM
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Removing the gun


Is a good idea, the question being how much does it contribute to nose weight. Would also take some of fear out of landing.....
Old Jan 25, 2013, 02:47 AM
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Hi Removing the gun is possible but it is contributing to nose weight as the cannon itself is alloy and sticking way out front, I was toying with the idea of replacing the muzzle with a steel tube as it would be the most effective way of adding nose weight
Old Jan 25, 2013, 05:39 AM
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I wouldn't worry about the WL Ken. My 119 is 109" ws and has a WL of 46 oz/ft., weighs 30 lbs, and flies like a 10 lb trainer. But CG, that's another matter. If you have to add lead to achieve, DO IT!

J
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Old Jan 25, 2013, 07:39 AM
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Thanks Pat, makes me feel much better, Ken
Old Feb 03, 2013, 01:10 PM
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Been slammed with work and preparation for a full Ofsted inspection so not much chance to get out to the garage.

Wings are now complete, several coats of primer and rubbed down ready for the next stage

Up next is the engine cowl plug
Old Feb 03, 2013, 02:10 PM
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I just can't get over the workmanship on this. It looks like you pulled it out of a mold instead of gluing together some dead trees. Well done.
Old Feb 03, 2013, 02:54 PM
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Hi Ken Have to agree with Mark here, outstanding!!
If it looks like you'll need nose weight (ie: lead), a perfect place to help would be thicker cowls than normal. A few ozs out there would go a long way in helping the balance. Just a thought Doug B
Old Feb 03, 2013, 03:17 PM
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Hey Ken ... beautiful is an understatement! Quick question ... did you machine your tailwheel ... if not where did you source it from?

Colin
Old Feb 04, 2013, 07:22 AM
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Thanks Everyone, Colin the tailwheel was from Hobby King, I think it was simply listed as a lightweight aluminium hub wheel
Old Feb 04, 2013, 09:13 AM
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Looking fabulous Ken, I bet those wings seemed like child's play compared to doing the 61 with the spoilerons?
Old Feb 04, 2013, 05:02 PM
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Quote:
Originally Posted by heli_madken View Post
Colin the tailwheel was from Hobby King, I think it was simply listed as a lightweight aluminium hub wheel
Sorry for not being clear Ken, I meant the tailwheel assembly, as opposed to the tailwheel itself. Looks like it's a trailing link/oleo set up ... I was looking for something similar hence my question

Colin.
Last edited by wollins; Feb 04, 2013 at 06:12 PM.
Old Feb 05, 2013, 02:25 AM
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Sorry Colin, I machined the yoke myself, its spring loaded so no need for an oleo, its just a hollowed out piece of alloy bar

Cheers yes it was a breeze to make the wings and they are so light compared to the Widow


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