Date: Tue, 18 Mar 1997 02:10:48 -0500 (EST) From: Lenpilot@aol.com Subject: Re: COZY: Aerodynamic Data for Airfoils? In a message dated 97-03-17 18:16:06 EST, you write: << -- [ From: James J. Cullen, Ph.D. * EMC.Ver #2.5.3 ] -- Hi Again: I'm interested in reverse engineering parts of the Cozy design -- mostly the airfoils -- and mostly just as a way of learning more about our aircraft. Does anyone know of a source of aerodynamic data for the Eppler 1230 (modified or unmodified) and Roncz R1145MS airfoils? I already checked Theory of Airfoil Sections and that book's data, while great for NACA airfoils, is too dated for what we need. About 2 years ago I asked John Roncz if he knew of a source of data for his airfoil and he said that he had never made any such data available nor did he know of a source for the data. Failing that, does anyone know of a computer program that lets you enter airfoil geometries to calculate aerodynamic data? Preferably one that doesn't cost me my first born? This would allow us to calculate aerodynamic data from our templates directly. Many thanks, Jim Cullen "The road to the launch pad is littered with the remains of many a promising career." >> Here is a crazy idea. call Nat Puffer and run your "reverse engineering" idea past him. That should give you insight into how he (rightly) feels about this type of request. My guess is that he would give a similar response as the one as Mr. Roncz. gave you already. Also, it is one thing to "reverse engineer" an airfoil. it is entirely another to modify the airfoil based on the results of any "reverse engineering". "Mostly learning" the aircraft is fine, That is why you bought the plans right? However if (as you put it) you do not want to cost yourself your "first born" I would suggest not modifying the aircraft in any (aerodynamic) way, and then allowing your "first born" to fly in it. "the road to the NTSB website is littered with the remains of many a smart guy who has grossly modified his proven plans." Leonard Farneth Cozy 4 # 522 lenpilot@aol.com Date: Tue, 18 Mar 1997 07:43:01 +0000 From: "David R. Kuechenmeister" Subject: Re: COZY: Aerodynamic Data for Airfoils? At 9:58 PM +0000 3/17/97, JAMES J CULLEN IV wrote: There's a site at UIUC that has alot of tabulated airfoil data. I don't know if there are pressure distributions or Cl vs. Cd curves tabulated for the airfoils. There is an interesting analysis program that is available on the site called "Profoil" I haven't used it, but I have been meaning to try it. The site is a http://www.uiuc.edu/ph/www/m-selig Regards, Dave >I'm interested in reverse engineering parts of the Cozy design -- mostly >the airfoils -- and mostly just as a way of learning more about our >aircraft. Does anyone know of a source of aerodynamic data for the >Eppler 1230 (modified or unmodified) and Roncz R1145MS airfoils? I >already checked Theory of Airfoil Sections and that book's data, while >great for NACA airfoils, is too dated for what we need. > >About 2 years ago I asked John Roncz if he knew of a source of data for >his airfoil and he said that he had never made any such data available >nor did he know of a source for the data. > >Failing that, does anyone know of a computer program that lets you enter >airfoil geometries to calculate aerodynamic data? Preferably one that >doesn't cost me my first born? This would allow us to calculate >aerodynamic data from our templates directly. > >Many thanks, > >Jim Cullen > >"The road to the launch pad is littered with the remains of many a >promising career." -- David R. Kuechenmeister Georgia Tech Research Institute Atlanta,GA 30332 mailto:David.Kuechenmeister@gtri.gatech.edu Voice: (770)528-7738 From: Epplin_John_A@hpmail1.90.deere.com Date: Tue, 18 Mar 97 07:25:42 -0600 Subject: Re: COZY: Aerodynamic Data for Airfoils? > In a message dated 97-03-17 18:16:06 EST, you write: > > << -- [ From: James J. Cullen, Ph.D. * EMC.Ver #2.5.3 ] -- > > Hi Again: > > I'm interested in reverse engineering parts of the Cozy design -- mostly > the airfoils -- and mostly just as a way of learning more about our > aircraft. Does anyone know of a source of aerodynamic data for the > Eppler 1230 (modified or unmodified) and Roncz R1145MS airfoils? I > already checked Theory of Airfoil Sections and that book's data, while > great for NACA airfoils, is too dated for what we need. > Here is a crazy idea. call Nat Puffer and run your "reverse engineering" > idea past him. That should give you insight into how he (rightly) feels about > Leonard Farneth > Cozy 4 # 522 > lenpilot@aol.com > I talked to Nat concerning the modified Eppler airfoil. He response was as Leonard suggested, "DO NOT CHANGE IT!". After I convinced him that that was not my objective, he was considerably more open and friendly. It seems that he got the airfoil from Rutan and does not have any detail data available. I found the original Eppler 1230 coordinates on a site maintained by the University of Illinois. After comparing these points with the drawings, I made new drawings up which very closely match the ones provided by Nat using the leading edge back to the spar and most of the upper surface from the Eppler points and the rest measured from Nats drawings. My objective here was the fabrication of the templates using N.C. equipment, not changing the airfoil. I did get the templates made using a laser cutter from 16 ga. steel. Two sets were made, one .032 oversize to use for the wire cutting, the other to sand to for the finish cores. One wing has been completed using the set. If I had to do it over again, I would make the oversize ones about .062 over. There was some low spots left after sanding. If you want more details, ask. I have the drawings in DXF format. John Epplin Mk4 #467 Date: Tue, 18 Mar 1997 08:27:16 -0500 From: william l kleb Organization: NASA Langley Research Center Subject: Re: COZY: Aerodynamic Data for Airfoils? David R. Kuechenmeister wrote: > There is an interesting analysis program that is available on > the site called "Profoil" I haven't used it, but I have been > meaning to try it. crazy as it may sound: unfortunately (for jim) this is an inverse airfoil design code. although the name sounds right for what jim wants to do, namely "reverse engineer"; an inverse design method works by specifying the airfoil's desired velocity (pressure) distribution and the code determines the airfoil shape. jim has the opposite problem of having the airfoil shape and wanting the velocity (pressure) distribution. -- bil From: UYFA59A@Prodigy.com ( JAMES J CULLEN IV) Date: Tue, 18 Mar 1997 16:37:39, -0500 Subject: COZY: Eppler 1230 Airfoil Coordinates (Unmodified) -- [ From: James J. Cullen, Ph.D. * EMC.Ver #2.5.3 ] -- At Dave Kuechenmeister's suggestion, I went web browsing for data on the Eppler 1230 airfoil. The University of Illinois has data on over 1100 airfoils tabulated and readily available at their website. The address over which I gained access is: http://opus.aae.uiuc.edu/~selig/ads/coord_database.html They do not have data for the Roncz R1145MS airfoil, although a cursory review of their database shows that they do have some of John Roncz' work and several airfoils from experimental and commercial aircraft. Their data is reporduced below, can be used for educational purposes, and is presented here for anyone who is interested in playing around with it (***Please don't even think of altering the airfoil on your Cozy !***). (Anyone desiring to use their data for commercial purposes needs to visit their web site and check out the usage agreement; they asked me to say that). The first set of data is for the upper surface and the second set is for the lower surface. I'm not sure what the "52" and "44" are -- perhaps some form of dimensionless data for the leading edge radius and tangent (a guess on my part)? Also, take note: The Cozy plans use a "Modified Eppler 1230." I'm not sure what the modifications entailed but I'll report back when I've plotted out the `stock' 1230 and compared it to our templates, as John Epplin did. John, hopefully I'll come to the same conclusions that you did about any modifications Rutan made to the `stock' 1230. John reported: " After comparing these points with the drawings, I made new drawings up which very closely match the ones provided by Nat using the leading edge back to the spar and most of the upper surface from the Eppler points and the rest measured from Nats drawings. My objective here was the fabrication of the templates using N.C. equipment , not changing the airfoil..." Anyway -- here's the data: EPPLER 1230 AIRFOIL 52. 44. 0.00000 0.00000 .00066 .00581 .00296 .01331 .00688 .02129 .01236 .02958 .01937 .03807 .02789 .04665 .03787 .05521 .04928 .06366 .06206 .07191 .07618 .07987 .09157 .08744 .10817 .09454 .12591 .10105 .14478 .10683 .16479 .11180 .18594 .11591 .20823 .11911 .23166 .12138 .25623 .12274 .28190 .12325 .30860 .12294 .33627 .12186 .36482 .12005 .39414 .11758 .42415 .11449 .45472 .11085 .48574 .10671 .51708 .10214 .54861 .09722 .58019 .09200 .61167 .08655 .64290 .08094 .67373 .07524 .70399 .06950 .73353 .06378 .76219 .05812 .78980 .05258 .81622 .04720 .84128 .04199 .86484 .03699 .88676 .03221 .90691 .02765 .92517 .02331 .94141 .01915 .95562 .01503 .96797 .01095 .97859 .00715 .98742 .00396 .99418 .00167 .99850 .00089 1.00000 .00010 0.00000 0.00000 .00002 -.00103 .00126 -.00675 .00507 -.01165 .01154 -.01641 .02015 -.02102 .03077 -.02538 .04334 -.02937 .05789 -.03294 .07441 -.03613 .09284 -.03898 .11309 -.04152 .13505 -.04378 .15860 -.04575 .18361 -.04745 .20997 -.04887 .23753 -.05000 .26617 -.05084 .29574 -.05139 .32610 -.05162 .35711 -.05153 .38861 -.05110 .42045 -.05031 .45249 -.04910 .48460 -.04739 .51674 -.04516 .54884 -.04239 .58083 -.03912 .61264 -.03537 .64419 -.03116 .67547 -.02648 .70000 -.02400 .72000 -.02200 .74000 -.02000 .76800 -.01800 .79400 -.01600 .82200 -.01400 .85000 -.01200 .88000 -.01000 .89800 -.00800 .92800 -.00600 .95200 -.00400 .98000 -.00200 1.00000 -.00010 From: UYFA59A@Prodigy.com ( JAMES J CULLEN IV) Date: Tue, 18 Mar 1997 16:37:22, -0500 Subject: COZY: Change the Airfoil?!!! Heavens, No! -- [ From: James J. Cullen, Ph.D. * EMC.Ver #2.5.3 ] -- John Epplin Writes: >I talked to Nat concerning the modified Eppler airfoil. He response was as Leonard suggested, "DO NOT CHANGE IT!". After I >convinced him that that was not my objective, he was considerably more open and friendly. That was my experience too. Nat and Shirley had dinner at our place about a year ago when they were vacationing here in Las Vegas. Once I told him that I had no interest in changing the airfoil (and I assuredly don't!) we got to talking about how he had modified it from the Long-EZ for use in the Cozy. Most of the modifications were in the internal structure (spar cap layup schedule) and most certainly not in the airfoil itself. >It seems that he got the airfoil from Rutan and does not have any detail data available. Yup, that's what I gleaned from our conversation, too. Jim Date: Tue, 18 Mar 1997 17:33:54 -0500 (EST) From: Nigel Field Subject: Re: COZY: Aerodynamic Data for Airfoils? At 04:58 PM 3/17/97 -0500, you wrote: >-- [ From: James J. Cullen, Ph.D. * EMC.Ver #2.5.3 ] -- > >Hi Again: > >I'm interested in reverse engineering parts of the Cozy design -- mostly >the airfoils -- and mostly just as a way of learning more about our >aircraft. Does anyone know of a source of aerodynamic data for the >Eppler 1230 (modified or unmodified) and Roncz R1145MS airfoils? ....... Jim, I can offer you or anyone else in the group, the co-ords of the Roncz airfoil as measured from the plans and also the pressure distribution pattern as computed by "Panel" which is a 2 dimensional airfoil performance application which does not provide for boundary layer in the total drag co-efficient. The output file includes all this data at 8 KB so easily Emailed. The Panel application is 204 KB which is more of a challenge but I can provide that also, just don't know the best way to send it if a bunch want it. You could run the Eppler 1230 through it and get those results also. I am not an aerodynamics engineer/expert or even pretend to be particularly knowlegable in that field but may be of some help. I use a modified Roncz Canard of my own design on my Vari-eze and have for 6 years with good results but then I also fly with a car engine so call me what you want, crazy, adventurous or just looking for a better solution. Nigel Field Date: Wed, 19 Mar 1997 08:04:29 -0500 From: william l kleb Organization: NASA Langley Research Center Subject: Re: COZY: Eppler 1230 Airfoil Coordinates (Unmodified) JAMES J CULLEN IV wrote: > I'm not sure what the "52" and "44" are ... these are the number of points on the upper surface and lower surface, respectively. -- bil Date: Wed, 2 Apr 1997 16:50:14 -0500 (EST) From: Nigel Field Subject: COZY: Aerodynamics site URL A few weeks back James Cullen asked some good questions regarding the effects of changes to airfoils. Below is a URL that offers an on-line text on airfoil properties and design, more stuff here than perhaps some of us can understand. It may help satisfy the curious. http://aero.stanford.edu/onlineaero/OnLineAero.html Nigel Field Date: Wed, 12 Nov 1997 23:13:30 -0800 From: "LCDR James D. Newman" Organization: INFINITY Aerospace - http://www.flash.net/~infaero Subject: COZY: Re: VariEze with Cozy Airfoil....?? Hi Mitch, Nigel and All, >Mitch Cannon wrote:< >>Does any one know of the correct airfoil for the VariEze airfoil? Are there any problems??<< >Nigel Field wrote:< >The Vari-EZE came several years ahead of the Long-EZE of which the Cozy is a wider version. The VE uses a GAW 1 (perhaps the GAW 2) laminar flow airfoil on the main wing . . .< Correct. I believe the VE has the GAW 2 laminar flow NASA airfoil, a popular airfoil in the late 60's, early 70's, which was one of the BD-5 airfoil options when Burt worked at Bede Aircraft. Problems Mitch: because the airfoil is a high pitching moment airfoil, some feel the VE is a little sensitive in pitch response, but it's not an unsafe airplane/problem to fly by any means. Hell, there are what, a 1000 VE's flying just fine in the world - I don't know (do you know Nigel?). But I think many like this (Nigel comments). If you've ever gone out and tangled (dogfight) with a VE in your Long-EZ, the VE will probably win. >. . . whereas the LE and Cozy (all variants) uses a modified Eppler turbulent airfoil which is quite different.< Correct. The main wing and winglet is an Eppler 1230 turbulent flow canard (I believe) airfoil that is modified by flatting out the cusp to make the airfoil a less pitching moment airfoil to be within certain parameters to work with a forward canard. Even though this airfoil is a turbulent flow airfoil, the Long-EZ, with a nice wing finish, has demonstrated this airfoil can still attain an impressive ~30% chord laminar flow. This test was done with a thin film of oil on a flying plane by RAF. See the CP's for a photo of the flight test results. >The canard airfoil on the VE, LE and Cozy III is a laminar flow Glasgow University (GU) airfoil which is known to exhibit a significant change in lift co-efficient when contaminated with bugs or moisture causing a pitch down stick force. The lighter the canard loading the more pronounced the change. Mine used to require about 30 lbs stick force in rain, one of the worst. A number of LE builders have changed to the Roncz 1145 MS airfoil to eliminate the pitch change in rain. A very few VE builders including myself, have retrofitted short Roncz canards for the same reason, but most VE and LEs still use the GU canard.< Correct. Just make damn sure you have all 3 vortilons installed on each side of the leading edge of each wing when using the Roncz 1145MS canard airfoil at all times. If you ever lose a vortilon (they do get knocked off at air shows), make sure you don't fly with the CG towards the aft limit, don't fly too slow, and keep your speed up and under control on final to be safe. If you keep the GU canard airfoil on the VE, LE and Cozy III, you'll be happy with the vortex generators you can put on the top of the canard (they have proven to correct the pitching problem to the GU canard airfoil caused from rain and bugs). I even think the vortilons are recommended (required? - Nigel) even if you keep the GU canard airfoil (vortex generators or not? - Nigel). HTH. Infinity's Forever, JD From: "Fred I. Mahan" Subject: Re: COZY: Re: VariEze with Cozy Airfoil....?? Date: Thu, 13 Nov 1997 07:29:07 -0500 > From: LCDR James D. Newman >big snip< >I even think the vortilons are recommended (required? - Nigel) even if you keep the >GU canard airfoil (vortex generators or not? - Nigel). RAF strongly recommended vortilons on the VE and LE, although a few people still haven't installed them. I believe they're mandatory if you install the Roncz canard on your LE, since it's more powerful than the GU canard -- that's why the Roncz canard is shorter than the GU. I've flown my LE both with and without vortilons at mid and aft CG's and they don't seem to make any difference. But, I'm not an aerodynamicist, so they stay on. RAF also said that under no circumstances was a Roncz canard to be installed on a VE, so you're on your own as far as angle in incidence and canard length if you do. But, this is a Cozy forum. Fred in Florida Date: Thu, 13 Nov 1997 12:20:05 -0500 From: David Domeier Subject: Re: COZY: VariEze with Cozy Airfoil....?? Nigel, Re "The canard airfoil on the VE, LE and Cozy III is a laminar flow Glascow University (GU) airfoil which is known to exhibit a significant change in lift co-efficient when contaminated with bugs or moisture causing a pitch down stick force. The lighter the canard loading the more pronounced the change. Mine used to require about 30 lbs stick force in rain, one of the worst." I think the performance of the GU canard when wet is a matter of builder luck. My airplane went into a 400-500 fpm descent when wet and trimmed out very easily. When it dried off the reverse happened. And I say all this from the perspective that I am a less than perfect builder of these machines. I do not have the patience to build the perfect airplane. I think the Roncz canard is a compromise some builders would rather not make. It solved the wet phenomenon, but it also stalls much later than the GU which has resulted in some pilots managing to get the wing stalled. You couldn't do that in the LEZ with the GU canard if it was rigged right and the cg was in the envelope. All in all, Burt Rutan designed a damn good flying machine in the LEZ, with or without the Roncz canard. If the MKIV flies as well as the LEZ does, I will be very satisfied. dd Date: Thu, 13 Nov 1997 12:22:14 -0500 From: David Domeier Subject: Re: COZY: Re: VariEze with Cozy Airfoil....?? Fred, re "I've flown my LE both with and without vortilons at mid and aft CG's and they don't seem to make any difference." I agree. I never installed them on my airplane either 'cause it flew just fine the way it was. dd Date: Thu, 13 Nov 1997 16:52:54 -0500 (EST) From: Nigel Field Subject: Re: COZY: Re: VariEze with Cozy Airfoil....?? At 11:13 PM 11/12/97 -0800, James D. Newman wrote: > But I think many like this (Nigel comments). If you've ever >gone out and tangled (dogfight) with a VE in your Long-EZ, the VE will >probably win. For sure. Not to brag, at least not too much, but I have never lost a dog fight with my little VE fighter. LEs are easy, RV3s are tough but still do-able. Never been against a Cozy (there Marc I used the word) but they should be easy too. Just wait till next spring, might make some shock waves. Nigel Field LCdr. (ret)