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Re: Canard Aerodynamics Presentation
Mike Tooze
Although I’ve only seen that first part of his presentation Marc is to be congratulated on trying to enlighten the pros and cons of the canard configuration to a wider audience. After all, the Wight brother’s experimentation, genius and understanding of the canard was not recognised in their county for some years. However, perhaps, to clarify an old chestnut. The high aspect ration conundrum. ‘Increasing the span to infinity reduces the drag to zero’, will send any mathematician with a passing knowledge of hydrodynamics looking for walls to climb. As Marc’s spotted streamline graphic shows that any practical aerofoil produces ‘lift per unit span’ normal to the flow and ‘drag per unit span’ parallel to the direction of flow. Thus increasing the span to infinity produces infinite lift and infinite drag, far from zero. What is not stated is a constraint, an arbitrary extra restriction, that total lift be equal to the weight of the aircraft (glider). Thus now as we increase span to infinity the lift and drag per unit span both tend to zero. But that still doesn’t prove anything. If we look at the behaviour of lift and drag against increasing alpha we see that for a practical aerofoil that drag increases steeper than lift. Conversely with reducing alpha, drag reduces faster than lift. Thus by increasing span so reducing required lift per unit span so drag is proportionately reduced further. Thus increasing span to some other limit, say, structural, so total drag is reduced under the constraint that lift equals aircraft weight. Lutom asks a good point re area rue and I suppose lateral acceleration of flow and the Cozy fuselage, I will look forward to seeing that section of Marc’s presentation. My 2d, Sincerely, Mike Tooze O-235 Vari Eze
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Re: Canard Aerodynamics Presentation
Marc J. Zeitlin
Lutorm wrote: The Raptor website... Oh, boy. Let me preface this by stating that I performed an examination of the Raptor aircraft, 15 months ago, prior to Wasabi Racing attempting to fly the plane, when Peter thought it was ready to fly in December of 2019, in an attempt to keep Justin and Elliot alive. That said, on to the questions... As far as I can find, the "Whitcomb area rule" which says you get more drag when the cross-sectional area changes, is only relevant for wave drag at transonic speeds. That is correct. Area ruling only matters at transonic speeds. There is no such thing as subsonic area ruling. There are drag reduction efforts at intersections that can reduce drag - this is why the winglets on our planes are set back 4" from the LE of the wing - so that the thickest portion of the wing and winglet don't occur in the same FS, but that's not the same as area ruling, which is a more global phenomenon and has nothing to do with intersections, per se. Do you have any idea whether this would actually matter for the speeds we fly at? Yes, I do. And the answer is absolutely not. There is not one aerodynamicist to whom I've spoken who hasn't pointed out exactly the same thing. Peter does not understand aerodynamics, or pretty much anything else about what makes airplanes or engines work. He's a very nice guy, but is in way over his head and I'm only glad that the engine failure (predicted by many) happened very close to the airport. The plane will never have anything close to the performance that was predicted using incorrect methodology and understanding.
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Re: Canard Aerodynamics Presentation
Lutorm
I had a question, actually:
The Raptor website made a claim that the drag will be lower if the cross sectional area has an as smooth a profile as possible and because a canard tends to not have the canopy and the wings occupy cross sectional area at the same fuselage station they have a smoother distribution compared to a conventional aircraft where the canopy and the wings tend to bulge out at the same time. It's gone from their website but I grabbed these pictures from archive.org: As far as I can find, the "Whitcomb area rule" which says you get more drag when the cross-sectional area changes, is only relevant for wave drag at transonic speeds. Do you have any idea whether this would actually matter for the speeds we fly at?
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Re: Canard Aircraft Aerodynamic
Tom Stichman
Thank you. It’s a great presentation and I’ll watch the rest tomorrow.
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Thx Tom Stichman
On Mar 3, 2021, at 21:48, Marc J. Zeitlin <marc.j.zeitlin@...> wrote:
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Re: LoVac troubles
Lutorm
Thanks for the responses everyone.
The pressure was 30kPa (-70kPa vacuum), which is what the pump is capable of. I'm pretty sure it's not drawing air into the layup, any leaks would mostly be where the hose enters or the plastic is folded. Even if there was another leak it should draw air into the paper towels first, but they were uniformly soaked. The paper towels were saturated with resin, and I definitely made sure the cloth and peel pry were wet. I used Pro-set 125 with 226 medium hardener.
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Re: Canard Aircraft Aerodynamic
Marc J. Zeitlin
Folks: A couple of folks have let me know that: Only 15 minutes is on your presentation. I have Dropbox but I’m unable to download any more. Is there more and how do you download it. It’s a great presentation so far. One solution was to download the whole file to their computer - then you'd be able to see the whole thing. But, to solve this stupid problem, I've uploaded the presentation to youtube at: Kind of a rough edit at the beginning and end, but hey - I'm no videographer. I've removed the Dropbox version, so this is it for now - no downloading required.
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Re: This Thursday's Builders Project Corner
stephen wolpin
I see. Let me know if it's possible. The GRT session will be a good one in any case—I'm on another Zoom call at exactly that same time... Steve
On 3/3/2021 10:39 AM, nosedragger48154
wrote:
Hi Steve, you’re correct, however I am the low man on the totem pole. People on our Board make those decisions. Then where do you store the data. I am not privy to any of that. Sorry.
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Re: This Thursday's Builders Project Corner
nosedragger48154
Hi Steve, you’re correct, however I am the low man on the totem pole. People on our Board make those decisions. Then where do you store the data. I am not privy to any of that. Sorry.
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Mike Scovel
On Mar 3, 2021, at 1:04 PM, stephen wolpin <swolpin@...> wrote:
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Re: This Thursday's Builders Project Corner
stephen wolpin
Zoom makes it easy to record. Understood about capacity. Good to have a record of meetings for yourselves too.
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Thanks, Steve Wolpin From iPhone
On Mar 3, 2021, at 9:56 AM, nosedragger48154 <ezdriver@...> wrote:
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Re: This Thursday's Builders Project Corner
nosedragger48154
Hi Steve, I will try, but I cannot make any promises. I know little if anything of our storage capacity for our meetings. I will check and find out.
Sincerely,
Mike Scovel SE Michigan VariEze
Mbl (313) 608-7202 Email ezdriver@...
From: canard-aviators@canardzone.groups.io <canard-aviators@canardzone.groups.io> On Behalf Of stephen wolpin
Sent: Wednesday, March 3, 2021 11:42 AM To: canard-aviators@canardzone.groups.io Subject: Re: [c-a] This Thursday's Builders Project Corner
Mike, Please have this Zoom session recorded (by whomever set up the meeting) and make the recording link available after. Thanks. Steve Wolpin KSZP LEZ N50MH From iPhone
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Re: This Thursday's Builders Project Corner
stephen wolpin
Mike, Please have this Zoom session recorded (by whomever set up the meeting) and make the recording link available after. Thanks.
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Steve Wolpin KSZP LEZ N50MH From iPhone
On Mar 3, 2021, at 6:13 AM, nosedragger48154 <ezdriver@...> wrote:
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This Thursday's Builders Project Corner
nosedragger48154
Hi Gang, we have been graced to have Greg Toman from Grand Rapids Technology presenting on our Builders Project Corner again! However this time it will be a Zoom Meeting this Thursday March 4th at 7:30 PM. See the attachment for more details, in addition if you have any questions this would be the best opportunity to get the answers! See below for the link to the meeting. I want to make sure everyone understands that it is Eastern Time! Looking forward to seeing everyone there!
Topic: EAA 113 Homebuilder's Meeting 2021 Sincerely,
Mike Scovel SE Michigan VariEze
Mbl (313) 608-7202 Email ezdriver@...
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Re: Canard Aerodynamics Presentation
Bill Allen
Thanks for sharing Marc. Most interesting presentation. Bill
On Wed, 3 Mar 2021 at 04:32, Marc J. Zeitlin <marc.j.zeitlin@...> wrote:
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Re: Canard Aerodynamics Presentation
Rick Hall
Thanks, will take a peek and see if can be whittled down to 45 minutes. If we use it, will letcha know as some may want autographs.
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Kevin knows you though, hangars a Pacer at TSP, works for Stratolaunch. Started with Scaled, then when Scaled split off Stratolaunch (or whatever), he stayed with the big airplane. His dad and I are pals at LMO.
On 3/2/2021 11:08 PM, Marc J. Zeitlin wrote:
Rick Hall wrote:
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Re: Canard Aerodynamics Presentation
Marc J. Zeitlin
Rick Hall wrote:
About 90 minutes, I think. There were a fair number of questions. Any thoughts on having Kevin Bickers speak at our Chapter? Not a clue who that is...
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Re: Canard Aerodynamics Presentation
Rick Hall
About how many minutes?
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Our Chapter has had James Voss talk, Jim Price is scheduled, may as well add another engineer to the mix. Any thoughts on having Kevin Bickers speak at our Chapter? Rick
On 3/2/2021 8:32 PM, Marc J. Zeitlin wrote:
Folks:
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Canard Aerodynamics Presentation
Marc J. Zeitlin
Folks: I was asked by EAA chapter 376 in Fresno, CA to give a presentation to their membership (I'm listed on the EAA Speaker Bureau website), and the presentation they chose was on "Canard Aircraft Aerodynamics - What's the Difference?". It was via Zoom, and they recorded it, so I've trimmed (roughly) the useless beginning and ends of the video and have made it available here as a 220 MB MP4 file (maybe eventually I'll put it on the "Presentations" page on the COZYBUILDERS site): The person recording it only had one screen, so the upper right corner of the screen is somewhat covered by some of the attendees faces (not everyone is a zoom expert...). But, luckily, you can view the original presentation given at the Columbia Fly-In in 2019 here: and follow along with the audio from the zoom recording. The slides aren't changed except for the footers and title page. Many of you will be unhappy with what you hear about canard aircraft, in which case I will consider my job as being complete :-). They seemed happy with the presentation, but all feedback, discussion and virtual rotten tomatoes are welcome.
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Need Long EZ Nose Gear assembly
Phillip Camarda
I am looking for a used (serviceable or non-serviceable) Long EZ Nose gear assembly. I need it for mock-up purposes. If you have one that you are not using setting around collecting dust please contact me. I will pay for shipping. Phil Camarda Please use this eMail: UH1CW2@...
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Re: Air intake selector valve
A terrible idea? If you are on a budget to go fast I think it was a great idea. The engine is always protected.
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Billy Rose. Longez builder on a budget
On Feb 19, 2021, at 10:26 AM, Bob Holliston <bob.holliston@...> wrote:
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Re: LoVac troubles
David Fife
I would like to know how much vacuum you are pulling. Another question, do you degas your epoxy before infusing. This eliminates most of the air in your mixture and aids in 100% saturation of the cloth.
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Dave Fife, long ez 12 Lz
On Mar 1, 2021, at 7:35 AM, Todd Carrico <tcarrico.cozy@gmail.com> wrote:
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