Home Depot Aviation Department

Silvaire said:
That is the horizontal stab. My point was that despite all of the ghastly things we noted on the Home Depot Homebuilt those big holes cut in the "spars" aren't necessarily one of them. For instance here's a picture of a stack of Maule spars at the factory.

Dave%20and%20Wing%20Spars%20Half%20Size.jpg
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Your point is valid, but I can assure you the RV main spars do not have lightening holes in them. There are holes in the ribs, and forward and aft spars, but not the main spars. Not trying to pic nits with you, just trying to keep facts accurate. :yes:

In the picture of the Maule parts I find it hard to believe those are main spars, but I'll take your word on it. It surprises me to see them stacked together like that. Scratches are a big no no.
 
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alfadog said:
Same as putting your left oar in the water. You turn left. Ailerons are like oars for airplanes.
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MU-2 spoiler turn syndrome.
 
Silvaire said:
That is the horizontal stab. My point was that despite all of the ghastly things we noted on the Home Depot Homebuilt those big holes cut in the "spars" aren't necessarily one of them. For instance here's a picture of a stack of Maule spars at the factory.

Dave%20and%20Wing%20Spars%20Half%20Size.jpg
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The problem is that the Maule spar is an I-beam and the flanges of the beam carry most of the bending load. In that case, the primary function of the web is to hold the flanges apart and the web carries only a small portion of the bending load. In this case, there are guidelines for lightening holes that I have forgotten but 75% of width is about the max, IIRC. The Home Depot spar has no flanges and all the bending moment is carried by the "web". In that case, you want to be very careful with the holes to ensure that sufficient material is untouched above and below the holes to carry the bending moments. Perhaps he did the required analysis and is fine. :wink2:
 
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Geico266 said:
Better rethink that! :yes:
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OK, if I am in a canoe and floating downstream with the current, what happens when I put my left oar in the water and hold it still against the movement (not rowing)? Admittedly, I do not do all the much canoeing but it seem pretty obvious to me that I would turn left.
 
alfadog said:
OK, if I am in a canoe and floating downstream with the current, what happens when I put my left oar in the water and hold it still against the movement (not rowing)? Admittedly, I do not do all the much canoeing but it seem pretty obvious to me that I would turn left.
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In your example above nothing happens. :no: The canoe would continue straight. It would only turn left if you paddled backwards on the left side.

Boats are not airplanes. ;)

If you are flying and you put the left alerion down the air hits the aileron and pushes the wing up, turning the plane to the right.
 
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Geico266 said:
In your example above nothing happens. :no: The canoe would continue straight. It would only turn left if you paddled backwards.
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Maybe my example is flawed in not showing relative motion between the canoe and the water. Try this. You have build up speed and are moving faster than the water. You put the left oar in and introduce drag on the left. You turn left, no? Not drastically, but noticeably.
 
alfadog said:
Maybe my example is flawed in not showing relative motion between the canoe and the water. Try this. You have build up speed and are moving faster than the water. You put the left oar in and introduce drag on the left. You turn left, no? Not drastically, but noticeably.
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Now you got it! ;)

I love canoeing white water. :yes:
 
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Other than the obvious shortcomings in engineering and fabrications, not sure why we all are being so hard on the guy. It's not like wooden airplanes haven't been flown before and quite successfully as well. The thing certainly would not fly safely, but at least he is trying and certainly as a instructional model it could be useful showing how aerilons, pitot tubes, etc function, and at the very worse it could be used for the annual fly in bonfire!
 
alfadog said:
Maybe my example is flawed in not showing relative motion between the canoe and the water. Try this. You have build up speed and are moving faster than the water. You put the left oar in and introduce drag on the left. You turn left, no? Not drastically, but noticeably.
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A canoe with a wing under the surface of the water with a left down aileron would cause the canoe to roll to the right and capsize to the right. :wink2:
 
douglas393 said:
Other than the obvious shortcomings in engineering and fabrications, not sure why we all are being so hard on the guy. It's not like wooden airplanes haven't been flown before and quite successfully as well. The thing certainly would not fly safely, but at least he is trying and certainly as a instructional model it could be useful showing how aerilons, pitot tubes, etc function, and at the very worse it could be used for the annual fly in bonfire!
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I though some of his engineering was actually quit good, just the wrong materials in his wing. I like the boat ladder! :rofl:
 
Geico266 said:
Now you got it! ;)

I love canoeing white water. :yes:
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OK, point taken. My only defense is that I was using the canoe as an analogue to an airplane which is, of course, moving faster than the surrounding fluid. Better might be a power boat and a sea anchor. Ailerons are sea anchors for airplanes? I still like oars better because I can picture rowing your airplane along by working the stick back and forth rapidly.
 
douglas393 said:
Other than the obvious shortcomings in engineering and fabrications, not sure why we all are being so hard on the guy. It's not like wooden airplanes haven't been flown before and quite successfully as well. The thing certainly would not fly safely, but at least he is trying and certainly as a instructional model it could be useful showing how aerilons, pitot tubes, etc function, and at the very worse it could be used for the annual fly in bonfire!
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I know, I know. Just that he is expending so much effort and could have been investing that effort in something that would actually fly and be relatively safe.
 
alfadog said:
OK, point taken. My only defense is that I was using the canoe as an analogue to an airplane which is, of course, moving faster than the surrounding fluid. Better might be a power boat and a sea anchor. Ailerons are sea anchors for airplanes? I still like oars better because I can picture rowing your airplane along by working the stick back and forth rapidly.
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Not really. While all surfaces on the airplane create drag, ailerons are used to defect air moving over the wing to apply force to the trailing edge of the wing up or down.

I might not have said that exactly correct either, but you get the idea. ;)
 
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alfadog said:
I know, I know. Just that he is expending so much effort and could have been investing that effort in something that would actually fly and be relatively safe.
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True, so true, but how much time do I invest in flying just to punch holes in the sky that could have been better spent doing other things. Sometimes doing something just for the fun of it is what makes it worthwhile.

Also, think of all the amusement he has given us, that's worth something.
 
@ you guys who state that lightening holes can't be used with wood...

...explain wood trusses to me.

...:rolleyes:
 
timwinters said:
@ you guys who state that lightening holes can't be used with wood...

...explain wood trusses to me.

...:rolleyes:
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I don't know that anyone said you couldn't put them in wood.....just that putting them in the wingspar might not be the best place, and as I said, I sure wouldn't want to put them in plywood....not that I would make a spar out of plywood in the first place.
 
I dont think I ever heard 'I've got the wing all framed up' before.

Does he know the guy from Kenya ?
 
Fearless Tower said:
I sure wouldn't want to put them in plywood....not that I would make a spar out of plywood in the first place.
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Holes in plywood and OSB aren't necessarily bad, you just have to put them in the right place just like you do in any other mat'l:

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Not aimed at you, but I do find it pretty funny when folks start arguing topics here that are far from their area of expertise. (I'd never argue that I'm innocent of this transgression, mind you). The post in this thread that made me laugh out loud was:

In that case, the primary function of the web is to hold the flanges apart and the web carries only a small portion of the bending load.
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While it's true that the flanges resist forces rotating around the vertical (yaw) axis, the web is the primary member for resisting forces around the longitudinal (roll) axis. So, it just depends upon which direction you're trying to bend the member.

I'm not trying to defend the guy's design, I have no idea if he's engineered it or not. And considering his creative use of a j-box, I'd boldly speculate...no. I'm just saying that there's a lot of "funny facts" being expressed here...some just as funny as his wing design.

I just hope some of these folks aren't really structural engineers and, if they are, I'd love to have a list of any highway bridges that they may have designed during their career so I can avoid them. :wink2:
 

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alfadog said:
Maybe my example is flawed in not showing relative motion between the canoe and the water. Try this. You have build up speed and are moving faster than the water. You put the left oar in and introduce drag on the left. You turn left, no? Not drastically, but noticeably.
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And yes, it does cause the plane to turn left briefly. This is called Aderse Yaw. It's due to increased drag on the left wing. But it is quickly surpassed by the horizontal component of lift induced by the banking of the plane to the right - creating a horizontal component of lift to the right which overcomes the adverse yaw. (Also, if the pilot is staying coordinated, the right rudder compensates for the adverse yaw and keeps the plane from turning left first.)

John
 
Fearless Tower said:
not that I would make a spar out of plywood in the first place.
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Why not? LaGG-3 had plywood spars, because Russians did not have access to aircraft grade spruce, and aluminum was scarce. It mounted a 1000 hp motor and did quite well against Bf-109E.
 
Geico266 said:
Your point is valid, but I can assure you the RV main spars do not have lightening holes in them. There are holes in the ribs, and forward and aft spars, but not the main spars. Not trying to pic nits with you, just trying to keep facts accurate. :yes:
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As I said, the first picture I posted was an RV10 horizontal stab which does have holes in the spars. I was looking for a picture of a Maule spar because having owned one and having done many inspections on them I know they have big honkin' holes in the main spar.

My point was in reply to someone who stated "OMG I can't believe he cut those holes in the spar" (or something to that effect) and I just wanted to point out that that wasn't such a big deal if we can get past the fact that the thing is three sections of plywood spliced together with wood screws. I just wanted to let people know that there are main spars out there with holes cut in them.
 
Geico266 said:
Not really. While all surfaces on the airplane create drag, ailerons are used to defect air moving over the wing to apply force to the trailing edge of the wing up or down.

I might not have said that exactly correct either, but you get the idea. ;)
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Now please don't make me feel bad by taking me seriously. :lol:
 
timwinters said:
Not aimed at you, but I do find it pretty funny when folks start arguing topics here that are far from their area of expertise. (I'd never argue that I'm innocent of this transgression, mind you). The post in this thread that made me laugh out loud was:

alfadog said:
In that case, the primary function of the web is to hold the flanges apart and the web carries only a small portion of the bending load.
Click to expand...

While it's true that the flanges resist forces rotating around the vertical (yaw) axis, the web is the primary member for resisting forces around the longitudinal (roll) axis. So, it just depends upon which direction you're trying to bend the member.
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Now you've got me laffing. Gotta love when folks spout off about others' "area of expertise" without the slightest idea of what that "area of expertise" might be. The main purpose of the main spar is to resist the bending loads induced by wing lift vs. aircraft weight, which loads, as we know, increase as g-loads increase in a banked turn. For that purpose, the I-beam is a very effective design. The majority of the bending load in an I-beam is carried by the flanges because, as you no doubt already know, resistance to bending is related to moment of inertia, which varies as the square of an element's distance from the neutral axis. But what do I know. :lol:
 
zaitcev said:
Why not? LaGG-3 had plywood spars, because Russians did not have access to aircraft grade spruce, and aluminum was scarce. It mounted a 1000 hp motor and did quite well against Bf-109E.
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IIRC the La-5 and La-7 also had wooden wings.
 
DavidWhite said:
IIRC the La-5 and La-7 also had wooden wings.
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I think the point here was the difference between plywood and high quality natural wood such as spruce. LaGG-3's construction was somewhat heavy and installation of a big radial engine did wonders to its performance. The structural plywood it used had its drawbacks. BTW, La-7 was largely aluminum. The same happened to the Yak line: as speeds and weight of armament increased, they had to phase in the aluminum alloys.

I was facetous about it, of course. I doubt that Home Depot sells the same grade of plywood that went into spars of La's.
 
zaitcev said:
I think the point here was the difference between plywood and high quality natural wood such as spruce. LaGG-3's construction was somewhat heavy and installation of a big radial engine did wonders to its performance. The structural plywood it used had its drawbacks. BTW, La-7 was largely aluminum. The same happened to the Yak line: as speeds and weight of armament increased, they had to phase in the aluminum alloys.

I was facetous about it, of course. I doubt that Home Depot sells the same grade of plywood that went into spars of La's.
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The below is an interesting article on the construction of those wing spars from an engineering standpoint. Note that they made something very similar in function to an I-beam with the web broken up into three parts.

http://www.flightglobal.com/pdfarchive/view/1943/1943%20-%202842.html
 
Silvaire said:
As I said, the first picture I posted was an RV10 horizontal stab which does have holes in the spars. I was looking for a picture of a Maule spar because having owned one and having done many inspections on them I know they have big honkin' holes in the main spar.

My point was in reply to someone who stated "OMG I can't believe he cut those holes in the spar" (or something to that effect) and I just wanted to point out that that wasn't such a big deal if we can get past the fact that the thing is three sections of plywood spliced together with wood screws. I just wanted to let people know that there are main spars out there with holes cut in them.
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Fair enough. :yes:
 
zaitcev said:
I think the point here was the difference between plywood and high quality natural wood such as spruce. LaGG-3's construction was somewhat heavy and installation of a big radial engine did wonders to its performance. The structural plywood it used had its drawbacks. BTW, La-7 was largely aluminum. The same happened to the Yak line: as speeds and weight of armament increased, they had to phase in the aluminum alloys.

I was facetous about it, of course. I doubt that Home Depot sells the same grade of plywood that went into spars of La's.
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when the germans started wanting longer wingspans and/or thinner airfoils they switched from Keifer (pine) spars to laminated spars, birch I think. stronger than Keifer so the spar could either be shorter for a thinner (faster) airfoil or the wing could be longer for the same thickness.
 
That looks like it will be extremely heavy, with a ton of problems.

Especially if its powered by 25 HP???

And the one commenter says he is a CFI? Thats scary.
 
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