|Sep 30, 2012, 09:36 AM|
I tore everything out of an old broken fuse and weighed the stuff that came from inside. With the exception of the rudder pushrod & teflon tubing, the elevator pull string, and the stab mount, I get 84g. Measured breakdown:
4x400mah & jack: 38g
Wing wiring + servo mount: 5g
V8R7 Rx: 8g
2x JR285: 19g
Total: 84g (scale round-off error 1g)
Obviously my 15g ballast is an easy place to look for weight savings. This points to my tail group, boom layup, and stab mount. The nose/tail length ratios are ~3:1 on this plane, so 5g tail savings could eliminate all 15g of ballast.
Curious if a couple folks can post their actual component weight break-downs to suggest if I'm basically on weight target or if I should trade $ for g (looking at the tail specifically).
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|Sep 30, 2012, 03:31 PM|
Wing servos 19g
Fuse servos 13g
Pushrods, horns, bolts, and throwing blade (hdwe) 6-8g
I don't typically use a wiring harness... normally I thread the wing wiring up to the receiver when I assemble the airframe.
Good tails at 13-14g a set can make an airframe. If you're over 16g on your tails (with mount), you are probably flying heavier than you could be.
PS... I have that same Horrible Freight scale and it's simply awful. Buy a good scale with .1g or .01g increments.
|Oct 01, 2012, 02:24 PM|
fuse 42g (super strong 47g)
2x DS H-09 18g
2x JR DS 285 18g
Rx + regulator 15g
|Oct 01, 2012, 05:35 PM|
United States, CA, Tehachapi
Joined Jun 2011
On my Mystic I'm flying now:
250mAh NiMh 25g
aileron servos 18g
elevator servo 5.7g
springs, peg, linkages, etc 16g
|Oct 01, 2012, 09:25 PM|
Great info guys. Thanks for posting weights. From what folks admitted ahead of the CG, I'm seeing that I should look much harder at my tail set, stab mount, and boom layup for overall weight reductions... Maybe I'll take a ruler and measure nose moments at ECHLGF to see if my pod is also too short :-o
To fill in all my data:
wing less servos: 141g
wing servos: 17g
stab mount: 1g
battery + switchjack: 38g
fuse servos: 19g
wing harness: 5g
AUW: 313g (as measured RTF)
Total: 313g (fudged tails to match AUW)
PS: Yes Tom, I hate that scale too. Haven't made a Harbor Freight run in a while, but know I need to get a better scale.
|Oct 01, 2012, 10:16 PM|
Joined Sep 2001
What is the distance between the wing TE and the stab LE?
Can you check where the cg is on the empty fuse? It would not be uncommon to have more weight in the boom than others might have.
|Oct 02, 2012, 09:39 AM|
Good point Gary. I was building fuses last year at 37-39g pretty consistently but they were balancing between the hingeline and TE. I had to add about 6-7g more noseweight to make those ships balance correctly. Since then I've changed my process and materials a bit and have been making 42-43g fuses that balance closer to the front bolt, and require only a gram or two for balance. They have three more layers of kevlar in the stress areas though so essentially they're MUCH stronger for the same AUW... even though they weigh more if you look at component weight.
|Oct 02, 2012, 10:25 AM|
United States, MD, Lusby
Joined Nov 2003
What wing is that? Either your scale is off (I have 3 and they are calibrated), or its a different wing than I am thinking.
19g for a tail set? Ouch, that is 24g of extra mass (6*3+6g). I don't think its quite that bad but maybe. Now you know why 12g tail sets cost $100+.
Aurora typical weights:
1) Wing: 130g
2) Tail set: 12g
3) Fuselage: 42g
4) Stab mount: 1.5g incl. bolts
5) Throwing peg: ~2g+carbon patch
Mass of fuselage electronics
1) 7 ch. FrSky Rx, V8R7 HV (7.7g)
2) 1x JR DS285 (9.8g)
3) 1x JR SM22 (9.4g)
4) 2S 350 mAh Zippy LiPo (21.1g)
5) Paul Daniels Voltage Reg (6.1g)
6) 14.4g of lead
7) 5g wing wiring harness
Things I'm not using but weighed for reference:
500 mAh 2S LiFe=30.7g
Also measured pushrods:
1) 0.021" steel+ #20 teflon=2.4g
2) 0.032" carbon+ #18 teflon=2.1g.
I wonder what a spring+line weighs, I'd bet sub 2g easily.
|Oct 02, 2012, 10:25 AM|
When I built the TS3 all the components that went into the nose were 50g. 2 HS45 JR6255 350 2C Lipo and regulator and wire harness. No servo tray was used and after it was done the installation added 51.5g.
|Oct 02, 2012, 12:42 PM|
|Oct 02, 2012, 02:30 PM|
This is a sample from my Sunrise #1 scratch build. It actually needed a few grams tail weight before changing the battery to lipo (nose length is 9" from wing L.E.). According to the sheet for Sunrise #3, it is on target to loose about a quarter ounce and is nearing completion
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