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| Construction Ideas, Hints and Tips For all the builders out there. Ask questions, make suggestions, trade tips. |
Topic Review (Newest First)
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| 01-16-2011 02:38 PM | ||
| Guest |
Re: How to cut cranked delta foam wing with complex curves and anhedrial? Good grief if you read through the thread he's ripping people off the same way he did when he was here. Just unbelievable any forum lets him participate. Dennis |
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| 01-16-2011 01:12 PM | ||
| moo |
Re: How to keep customers happy wow, again? I have to admit I forgot to pay some bills as my father died, but that's a bit much. edit: I see you're reading messages here, good luck Sam |
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| 01-16-2011 11:07 AM | ||
| Max |
Re: How to cut cranked delta foam wing with complex curves and anhedrial? Quote:
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| 01-16-2011 09:19 AM | ||
| Mike Emilio |
Re: How to cut cranked delta foam wing with complex curves and anhedrial? Just saw this on RCG http://www.rcgroups.com/forums/showt...234671&page=28 I guess with all the problems with medical and Mr Lee, the Concord will be along way from finishing. |
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| 05-28-2010 02:28 AM | ||
| LuvEvolution7 |
Re: How to cut cranked delta foam wing with complex curves and anhedrial? if you read correctly, which you obviously didn't, I didn't say it had "nothing" to do with lift at all. I said it's a part of it, but not the whole story. but I expected you to disagree with what I said anyway, so it's no big deal. as I said, old train of thought is no longer relative in today's understanding of lift and how it is produced. that's why CL is no longer looked at the way it once was. you can't expect a wing to be making a certain amount of lift at a certain point. again, that's an old train of thought that is severely outdated. lift doesn't have to be about boundary layer at all. if that were the case, deltas wouldn't fly on vortex manipulation, which they obviously do. that has nothing to do with boundary layer, or Coanda effect, whatsoever. so we can see there's two sides to the story and neither are altogether correct. as far as deltas are concerned, the ogee and cranked arrow produce lift in exactly the same way. it is only their shape that is different. they both serve to move the vortex rearwards on the outer panel of the wing surface. you can argue that point all day long, or till you are blue in the face for all I'm concerned, but they still both do the same thing more efficiently than a straight LE delta. but of course, I'm sure you'll disagree with this, just cause you can. as far as sailboats are concerned, lots of things differ from what I'm sure you learned when you were a teen. sailboats no longer are limited to speed, based on wind speed. these days, they are often reaching speeds in excess of three to four times the wind speed they are running in. the BMW/Oracle boat for the Americas cup has reached 3 times windspeed with ease and has the capability to reach beyond four times wind speed. they aren't using a traditional sail anymore and it is more akin to a rigid airplane wing. so just as in aircraft, things change. |
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| 05-23-2010 04:08 PM | ||
| moo |
Re: How to cut cranked delta foam wing with complex curves and anhedrial? Quote:
In one breath boundary layer and in the next you say it has nothing to do with Coanda Effect, odd. This differs from what I learned racing and tuning sailboats in my teens. If Ogive is the same shape as Cranked then a sine wave is the same shape as triangular and RMS power is a figment of my imagination. We need to disagree on these things. At least my college math instructor would. One thing we can agree on is that the volumetric shape doesn't matter very much until you fly full scale and have to worry about fuel efficiency. There are lots of people flying flat foam delta wings, even as slope soaring gliders. |
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| 05-23-2010 01:34 PM | ||
| LuvEvolution7 |
Re: How to cut cranked delta foam wing with complex curves and anhedrial? they are still both considered to be cranked arrow in design. the ogee utilizes the effect with a smooth transition instead of a sharp one. they still both do the same thing though and that is to move the vortex stream towards the rear of the outer panel, which moves flow seperation to the rear, which gives more lift at higher AoA. as far as that foil is concerned, at the Reynolds numbers we see at our model scale, it doesn't matter if the wing is flat or curved. the drag numbers produced aren't really all that different. at full scale, it makes a huge difference, which is why you don't see them used. as Eric said, the proper term would be planar. another proper term would be Viscous Thin. those are both terms you can easily search. not sure why Henri Coanda would be truning in his grave at what I said, since the Coanda effect is NOT responsible for lift in any way, shape or form. it only adds to lift by means of entrainment, which is why it is utilized in high lift devices, such as flaps and blown surfaces. foils do not produce lift because of Coanda effect, or because of Bernoulli effect. these are both very outdated ways of looking at things and are both wrong. certainly, I would agree that both are an essential part of lift theory, but there's more going on here than can be explained away with these theories. so I think Henri can go back to resting in his grave knowing that I haven't spoiled any lift party. LOL. the bottom line is, Sam's Concorde will fly the same way, whether it's got a "plate" foil or a classic curved foil. it's not going to make one bit of difference at model scale. there's plenty of model Concorde's flying around the world to prove you wrong if you disagree with that statement. plus, there's plenty of witches, school buses, lawn mowers, etc, etc, that are flying using the same principles as mentioned and they fly just fine, without the use of curved airfoils. and before I get the arguement that they aren't flying as fast...................speed makes no matter at our Reynolds numbers. stability remains the same as Reynolds numbers increase, but drag increases slightly. so the only thing Sam should have a problem with is bleeding speed in turns and higher alpha flight. but he also has four 70mm EDF's pumping out some rather high efflux speeds, which will more than make up for the bleeding of speed. keep going Sam, it's gonna work well. Rich |
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| 05-23-2010 09:42 AM | ||
| moo |
cranked versus ogive Just a passing thought - ogive requires a nice smooth transition, cranked is more like two wings, inboard and outboard... |
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| 05-18-2010 12:34 PM | ||
| Mike Emilio |
Re: How to cut cranked delta foam wing with complex curves and anhedrial? Quote:
Suffered some water damage. Pictures on RCU show that it has also suffered accidental tail damage. |
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| 05-18-2010 08:57 AM | ||
| moo |
Re: How to cut cranked delta foam wing with complex curves and anhedrial? Quote:
Kit Cutters' price is $500 plus $100 for the plans. But we seem to be off topic here, I think the Concorde will be a very ambitious project and we may learn some more about aerodynamics and cutting foam. Where are you planning to fly the Concorde Sam? I've only seen grass runways around S. Ontario and Peter usually breaks something at our field since it's so rough. |
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