Henschel HS129 B-3 - Page 15 - RC Groups
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Jan 24, 2013, 11:43 AM
Failure is not an option
casor's Avatar
Originally Posted by heli_madken
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.
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Jan 24, 2013, 12:06 PM
eye4wings's Avatar
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?
Jan 24, 2013, 12:09 PM
Registered User
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.
Jan 24, 2013, 02:07 PM
Failure is not an option
casor's Avatar

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.....
Jan 25, 2013, 02:47 AM
Registered User
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
Jan 25, 2013, 05:39 AM
EB-66C Team Member
J Morgan's Avatar
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!

Jan 25, 2013, 07:39 AM
Registered User
Thanks Pat, makes me feel much better, Ken
Feb 03, 2013, 01:10 PM
Registered User
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
Feb 03, 2013, 02:10 PM
Flying electric since 1986
Mark Wolf's Avatar
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.
Feb 03, 2013, 02:54 PM
Registered User
Doug Bartley's Avatar
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
Feb 03, 2013, 03:17 PM
"RC ADDICT" in Toronto!
wollins's Avatar
Hey Ken ... beautiful is an understatement! Quick question ... did you machine your tailwheel ... if not where did you source it from?

Feb 04, 2013, 07:22 AM
Registered User
Thanks Everyone, Colin the tailwheel was from Hobby King, I think it was simply listed as a lightweight aluminium hub wheel
Feb 04, 2013, 09:13 AM
Registered User
Ducky22's Avatar
Looking fabulous Ken, I bet those wings seemed like child's play compared to doing the 61 with the spoilerons?
Feb 04, 2013, 05:02 PM
"RC ADDICT" in Toronto!
wollins's Avatar
Originally Posted by heli_madken
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

Last edited by wollins; Feb 04, 2013 at 06:12 PM.
Feb 05, 2013, 02:25 AM
Registered User
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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