H.Zwakenberg
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Posts posted by H.Zwakenberg
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Here is one example of high wing canard versus low wing main wing,
RMT Aviation Batelelur. The canard seems to be placed back enough
to ensure that the wake turbulence goes over the main wing.
http://www.pilotmix.com/index.php?pgid=11&lang=en&maxInfo=158
Mid wing configuration in Cozy/whatever decreases induced drag as far as I have understood.
The advantage of low wing back wing would be of course the advantage of Bateleur: the propeller is placed above the main wing so that the main wing protects the propeller from dirt etc. The Bateleur is approved for dirt, grass etc. fields. The another thing in Bateleur is that the canard does not block visibility to any direction as it is behind the pilot's seat.
in a German aviation magazine (I believe it was Flieger Magazine) I read a few years ago that the Bataleur was conceptually designed as a flying wing (i.e. cg far aft, zero-moments section on the main wing) and that the canard wing was merely used for trimming purposes, supposedly to even out payload variations. Interesting concept. Also, an interesting plane, one that just cries for some external stores hardpoints and a paint job to match
bye
Hans
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Also, as Jon mentioned there are several CFD (Computational Fluid Dynamics) programs available and I have used several of them including X-Plane but I feel that there is still room for error and their version of your aircraft should not be taken as gold.
Aerodynamix:
please note that X-Plane is not a CFD.
Computational Fluid Dynamics software is used to determine the flow of many, many "air-cells" if you will, that wrap an object (in our case an aircraft) on the outside. Also, this gridding of the space from the object is continued to the outside, very often multiple spans away from the object. For each of these grid cells, CFD software calculates the local air pressure, the air stream 3D direction and the correspondig air velocity. What makes CFD so great, is that the interaction between all those cells is also considered.
X-Plane on the other hand only coursly grids the wing(s), control surfaces and propeller blades. It does not grid the outside environment. With this course grid, it does force and moments estimates for each of those points. Calculation the resultant forces, moments and speed is done by an integration of all cells. Austin Meyer, the author of X-Plane, utilizes what is called 'blade element theory' to do these calculations.
Blade element theory is much easier to calculate than a full CFD. Current computers can't handle complex CFD jobs that would allow realtime behavior calculations that would be needed for simulations. Blade element theory can do that, but the results are less precise.
It's a matter of horses for courses...
bye
Hans
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Thanks for the good info here. On the price: That makes me feel real good about my investment considering mine is a 1992 model with 600TT and full IFR day night certification and a 160 HP engine. I hope to fly it home next week. I will post the results. I have contacted AOPA about getting insurance for it and they believe they can help me. Should be an interesting experience if nothing else.
From 1992? In that case you must have purchased one of the last to be produced, ever. I'll check my files to be a bit more specific on this.
As to Jon's assertion about the VariEze roots: there is some merit in that statement, although not entirely correct. The initiator of the SpeedCanard project had built a VariEze for himself. He though about putting it through the normal certification procedure but soon realized that this effort would prove futile. He then decided to design from scratch. He assembled a team of engineers and found some financial backing. That's how SpeedCanard was bootstrapped. Much of my aviation documentation is still stored in cartons, because I moved a couple of months ago. I might be able to retrieve a bit more precise information....
bye
Hans
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for those of you also interested in purchasing a SpeedCanard, I know of three others that were put up for auction.
Check out: SpeedCanards on auction
take care,
Hans
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Still didn't get the Nov. issue. Snailmail can't be that slow, or can it?
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In theory this is correct, but which cylinder is the hottest?? The hottest Cyl can change due to power settingsand other factors, both normal and abnormal.
The real advantage (other than LOP operations) is that looking at each cylinder, you can many times diagnose ignition, injection, etc problems with a glance to the instrument. A full egt/cht unit can sometimes indicate pending problems before they become critical--- That is, of course if one looks at it and understands the meaning of what is being measured and what variations of the data means.
On the other hand, if you have no desire other than to lean to roughness and then enrich slightly, you don't need an EGT at all. CHT (on one cylinder, I think, is required, however
As far as I was informed - and in the context of my project, an IBIS pusher canard powered by a VW derivate - the #4 cylinder (starboard/aft) should be the hottest. Might be a simplification though, I don't know. Perhaps someone can enlighten me on this topic?
thanks,
Hans
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If you're flying a VFR day-only experimental, you need NO INSTRUMENTS except perhaps an ELT and a transponder:
http://rotarywiki.org/Minimum_Inst_Requirements.html
It took some doing to convince me, but 91.205 -- the FAR that lists the required instrumentation -- applies only to aircraft with standard airworthiness certificates. As experimentals, we are issued special airworthiness certificates. 91.205 doesn't apply to us. Now, the rules become applicable when equipping for night and IFR ops.
As for coordinated turns, doesn't the yarn, string, eventually scratch up the canopy glass?
In European countries, things are a bit more complicated than this.... Essentially, over here we need those instruments, that non-experimental planes would legally need to carry.
bye
Hans
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another suggestion/question:
will it suffice to just monitor the hottest cylinder, or is there solid merit in fully instrumenting the engine?
bye
Hans
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Being a former sailplane pilot, it dawned on me that - with pusher aircraft - you don't need a slip indicator. Just do as sailplane pilots do: take a bit of tape and use it to attach a 2-3 inch long tuft on the centerline of your cockpit. That string tells you all you need to know - and quite a bit faster than that liquid damped slip indicator. Don't take wool, cotton or another natural fiber, as these cease to work when flying through a rain shower....
bye
Hans
[edit:] if you fly N-VFR or IFR, this might not be a good suggestion
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How metric can you go? It wouldn't be complete without abandoning the standard 360° for a full circle, as this caused the derivation of a nautical mile, which happens to be the awkward 1.852 meter...
cheers,
Hans
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Thanks for that second link as well. I added it to the list.
bye
Hans
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Janathan,
Free advice is usually too costly, however, if you are just at your tub-- hold off. Avionics, and for that matter engines, are changing so rapidly that it is almost like buying a computer. I can almost guarentee you that by the time you are ready to fly, there will be a box that is lighter, cheaper and does many more functions, including those that you can't even think of now.
This comes from someone who for a previous homebuilt bought a Garmin 812(loran), had it converted to an 816 (loran) and traded that in on a GX55(gps) which was the only radio to fly. I also had a 196 garmin (the flying brick) sold that to get a 296 and drool over a 396. Knowing that my aerocanard won't be ready for at least 1 1/2 years, I am holding off--- Anybody looking for a very slightly used 296?
I second Rich. Integrated digital electronics being what it is, it's very likely that prices will fall and capabilities will increase. I don't expect it to be as dramatic as with consumer electronics, the market simply isn't that big, so scale effects are - in our case - detrimental.
On another note, you might find it interesting to learn that several open source EFIS projects are under way. Some of them are registered on sourceforge.net. Hopefully, one of them will have matured by the time I need to equip my IBIS. Like Rich, I'm going to purchase my digital stuff as late as possible.
bye
Hans
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Thanks Jon, for that link. I included it in the links list on the Yahoo group.
Since my initial call anouncing this new group a couple of days ago, we've had over 130 members to sign up! I don't know if this is 'standard Yahoo operating practice' but these numbers keep amazing me to no end....
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Oh man,
couldn't you have held that back a bit? Being located in Europe, the wait is going to be that much harder!
bye
Hans
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Hi Canard Zone members,
preparing for my experimental IBIS canard project, I discovered that propeller design and propeller building information isn't really collected in a single place, so that everyone can benefit from it.
To this end, I set up a Yahoo-group about exactly this topic.
One day, you'll be ready with your project build and engine installation and you're going to need a prop. Please consider joining our Experimental Aircraft Propeller Building Group by opening the following URL:
http://groups.yahoo.com/group/propeller/join
take care,
Hans
_____________________________
My homebuilt aircraft project
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Hi Rick,
thanks a lot for that information. I dug up another prop calculation resource on the internet. You can find it on: THIS SITE
It's a Java-based software, either running inside your browser (JavaScript) or downloadable on your computer (Java). I'm going to try this out the next weekend.
take care,
Hans
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Hi Ron,
too bad I didn't spot your offer two weaks earlier; oh well, a Sennheiser will do as well, I reckon. Good luck with the sale!
bye
Hans
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Try this little calculator
It worked out almost exactly on my Long
http://www.culverprops.com/pitchselection.htm
Rick
Hi Rick,
thanks a lot for that URL, very useful!
While it answers the eternal question about what pitch to select, my other concern isn't addressed there. I assume that since pusher props see dirty air, laminar sections don't make sense for this application. This leaves the more conventional sections. I'd like to design/carve my own prop and am somewhat at loss about what airfoil sections to use for this specific application.
You wrote that the calculator worked out almost exact on your LongEze. Could you please write a few words about what deviations you discovered?
thanks!
bye
Hans
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Hi Group,
currently I'm building an IBIS canard, a two-seater which will be powered by either an AeroVee or a Jabiru. Both engine sport appr. 80HP at around 3300 RPM. The max. speed will be around 115-120 Kts.
My question: I'm thinking about what prop to use. Since a pusher prop only sees 'dirty' air, I assume that it's no use to mount a propellor with modern laminar sections.
Does anyone has experience or pointers to information sources about this topic? As I'm based in Europe, noise emission (or better: the reduction thereof) is very important too...
bye
Hans
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I like flying too much to be able to concentrate on just building an aircaft. Since I don't have a deadline for my project (it will be ready when it's ready) I don't feel too bad about staying current...
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No, that Todd guy rocks... My IBIS canopy came out of his shop as well. It's very nice indeed....
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Is 'stall resistance' something that's discussed in the IBIS community?
I'm rather new to the (still rather tiny) IBIS community. My first impression is, that IBIS builders generally don't exchange information all that much. There's a Yahoo community , currently with only 81 members. Of these, less than 10% are actual builders. There are other reasons why open communication isn't flourishing within this community, but I'd rather comment on that in a PM...
As to stall behavior: of course the front surface needs to stall first and apparently, so it does with IBIS. The designer didn't use any modern laminar sections, so I think the old problem of flying in rain or flying bug littered is as critical as it used to be with the Rutan designs and their derivatives. The canard wing looks like a slotted NACA 23015 to me, but I haven't really compared the ordinates just yet. The section of the main wing is a bit fuller and the location of the maximum thickness is a bit further aft, but it still is a conventional (non-laminar) section.
Since the IBIS is cruising with appr. 10° up-elevons, I'd like to know how she stalls in that configuration. So far, no one gave me the skinny on that, I have to consult with JC to learn more about this...
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The stick you see on the picture that I mentioned above is the rear seat stick, or more precise: the stub over which the rear stick proper will be placed. It follows that a rather large part of the mixer assembly is located below the rear seat...It took me a while to realize that the primary control stick is in the middle, between the legs, as opposed to the stick on the mixer apparatus. I'm still not quite sure I get it, but continue to be impressed with the engineering.
To be honest: I don't know, as I took over the paperwork (drawings/license, etc) from an abandoned project. I contacted JC and he confirmed in writing that the license transfer was ok.How much are the plans these days?
Just Bought a GyroFlug Speed Canard
in Speed Canard
Posted
On sailplanes the performance difference on an otherwise tuned ship is noticable. Also consider the fact that preventing any leakage in the cowling area will provide your prop with cleaner (i.e. less disturbed) air which should improve propulsion efficiency. Soooooo, my hunch is that you should indeed tape the seams...
bye
Hans