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#11
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You cant increase your speed by 20%...but you CAN DECREASE your useful load
by about 12% (if I have my numbers right). Fir is a little heavier than Spruce. Dave...D as in "Duh"...A...V...E "Lou Parker" wrote in message om... Del Rawlins wrote in message ... On 26 Oct 2003 06:24 PM, Lou Parker posted the following: Can anyone tell me the truth? When I read articles about the difference between the two woods, the information says that fir is 23% stronger than spruce. When I talk to people they say only 10%. Anyone got a handle on this? The difference between the two, is that sitka spruce will often forgive less than perfect technique, while doug fir will split if you so much as think the wrong thoughts about it. Sometimes even if you don't. Spruce, on the other hand, is a joy to work with. A few years ago I turned some unairworthy citabria spars into parts for a canoe. Still hoarding the one leftover spar for future use. 8^) ---------------------------------------------------- Del Rawlins- Remove _kills_spammers_ to reply via email. Unofficial Bearhawk FAQ website: http://www.rawlinsbrothers.org/bhfaq/ Does that mean that after building my plane with fir instead of spruce that I should be able to up my cruise speed, max speed and everything else by 20%? Lou |
#12
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On Thu, 30 Oct 2003 17:17:15 -0500, "D Reid" wrote:
You cant increase your speed by 20%...but you CAN DECREASE your useful load by about 12% (if I have my numbers right). Fir is a little heavier than Spruce. I just finished a new battery box for my Fly Baby. Actually TWO battery boxes, after the first one (made of oak) got laughed out of my EAA chapter. (Hey, I do a bit of non-aviation carpentry. I *love* working with oak!) FWIW, the poplar one weighed 1.25 pounds. The nearly-identical oak one weighed a half-pound more... a 40% weight penalty. Ron Wanttaja |
#13
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You cant increase your speed by 20%...but you CAN DECREASE your useful load by about 12% (if I have my numbers right). Fir is a little heavier than Spruce. I just finished a new battery box for my Fly Baby. Actually TWO battery boxes, after the first one (made of oak) got laughed out of my EAA chapter. (Hey, I do a bit of non-aviation carpentry. I *love* working with oak!) FWIW, the poplar one weighed 1.25 pounds. The nearly-identical oak one weighed a half-pound more... a 40% weight penalty. Ron Wanttaja ++++++++++++++++++++++++++++++ SO????? Won't your Fly Baby carry a half-pound? If not, fly barefoot and save 300% or more. g Barnyard BOb -- If flying is the most fun you can have with your clothes on... How much fun can flying naked be? |
#14
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I just finished a new battery box for my Fly Baby. Actually TWO battery
boxes, after the first one (made of oak) got laughed out of my EAA chapter. (Hey, I do a bit of non-aviation carpentry. I *love* working with oak!) FWIW, the poplar one weighed 1.25 pounds. The nearly-identical oak one weighed a half-pound more... a 40% weight penalty. I'd have thought you'd use spruce, it's even more poplar... :-) Ed Wischmeyer |
#15
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In article , Ron Wanttaja says...
I kinda like either Black Walnut or Balsa :-) But I also think the subtle hues of Cherry can blend into a harmony of tones that are a feast to the senses.... I really liked the use of Oak tho' it was a nice touch. Chuck S I just finished a new battery box for my Fly Baby. Actually TWO battery boxes, after the first one (made of oak) got laughed out of my EAA chapter. (Hey, I do a bit of non-aviation carpentry. I *love* working with oak!) FWIW, the poplar one weighed 1.25 pounds. The nearly-identical oak one weighed a half-pound more... a 40% weight penalty. Ron Wanttaja |
#16
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I wrote:
FWIW, the poplar one weighed 1.25 pounds. The nearly-identical oak one weighed a half-pound more... a 40% weight penalty. [Answering three responses to this message] On Tue, 04 Nov 2003 05:53:13 -0600, Bob U. wrote: SO????? Won't your Fly Baby carry a half-pound? If not, fly barefoot and save 300% or more. g Ah, BOb, it's one of them engineering things. Like to get things as efficient as I can. However, I did provide the worst-case view of the actual numbers. The half-pound difference above was just for the wood that went into the basic structure of the new battery box. By the time the removable bottom, various anchor nuts, aluminum mounting flanges, mounting bolts, etc. were factored in, the difference wasn't as strong. With poplar as the basic structure, the all-up, ready-to-use box weighed 2.5 pounds. So if I'd used the oak, the penalty would have really been only 20%. The box I replaced (the old box was for a standard aircraft battery, the new one was for an Odyssey drycell) weighed five pounds. So even with oak, I would have had a 2-pound savings. FWIW, here's the numbers for my conversion from a Gill G-25 to the Odyssey PC680: Battery: Gill G-25: 20 lbs Odyssey: 14 lbs, including metal case Battery Box: For Gill: 5 lbs For Odyssey: 2.5 lbs Total weight savings was 8.5 pounds...less than I expected, because I had anticipated the Gill battery was heavier. Still, the weight saving was a secondary reason for the conversion. The old battery box and the large battery only allowed access from above, and a box containing most of my avionics actually mounted atop the battery. This meant that I had to disassemble my electrical system *live* to access the battery far enough to disconnect the cables. Ron didn't like that. New, flatter battery is mounted on its side, accessible (and disconnectible!) from below the aircraft. To get access to it, I cut a 1'x3' hole in the belly fabric and install an access panel. But then, I had to do fabric work anyway because I had to glue down the loose edges of the fabric on the rudder when I cut away the gaps seals to remove it to fix the dry rot in the tailpost, which I discovered when I started to install a modified tailwheel spring support bracket. Let's just say I've had a busy two months. On Tue, 04 Nov 2003 05:57:32 -0700, Ed Wischmeyer wrote: ]I'd have thought you'd use spruce, it's even more poplar... :-) ] ]Ed Wischmeyer Poplar was oakay fir my purposes. Besides, they don't sell spruce at Home Depot Aerospace. :-) Chuck S. posted: }I kinda like either Black Walnut or Balsa :-) But I also think the }subtle hues of Cherry can blend into a harmony of tones that are a }feast to the senses.... Last year, I noticed that my wing "arrows" (wooden dowels tied to the wing bracing wires to damp vibration) were a bit dry-looking and needed revarnishing. I have a ton of stuff from various wood projects sitting around, so I used some cherry stain on the arrows before varnishing them. I like the effect, but it gets a few strange looks at fly-ins.... Actually, a buddy of mine says my old box was made out of Beech. Ed will probably get a lot of mileage out of that one.... Ron Wanttaja |
#17
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In article ,
Ron Wanttaja wrote: [[.. munch ..[[ Actually, a buddy of mine says my old box was made out of Beech. Ed will probably get a lot of mileage out of that one.... Obviously, then, the new box is a son of a beech. |
#19
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"Ron Wanttaja" wrote in message ... snippage Actually, a buddy of mine says my old box was made out of Beech. Ed will probably get a lot of mileage out of that one.... Ron Wanttaja So is the new box "Son of the beech"? Tim Ward |
#20
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