From: michael.amick@nashville.com Subject: COZY: HiPerf IVO Prop Inflight Adj. Date: Fri, 3 Jan 97 00:48:00 Organization: The Nashville Exchange-http://WWW.NASHVILLE.COM Michael Link here in Nasville is looking for a prop for his MkIV that is nearing completion and is considering the IVO inflight adjustable model (this model has no govenor and is not "constant-speed" as mentioned by someone earlier). He has heard via others (read rumor) that this prop was in several RV incidents and asked me to find out all available info from our builders group. Please respond with "KNOWN" information and with references to keep rumors to a minimum. HAPPY NEW YEAR TO ALL!! Michael.Amick@Nashville.com EAA Chpt 162 MkIV #317 Chapter 5 (rebuilding my sides w/RAE) Date: Fri, 3 Jan 1997 02:44:08 -0500 From: INFINITY Aerospace <72124.347@compuserve.com> Subject: COZY: Constant Speed Prop Hi to All, >Michael Amick wrote:< >Michael Link here in Nasville is looking for a prop for his MkIV that is nearing completion and is considering the IVO inflight adjustable model (this model has no govenor and is not "constant-speed" as mentioned by someone earlier).< Hi Mike, I posted the following 09/06/96. Mike Link may want to check out this prop, also. >>Hi to All, >Reid Siebert wrote:< >>snip<< >Invest the $12,000 in a good constant speed prop, it will help you to safely get more horses out of your engine.< We will be using a 72" diameter, 3 blade, constant speed prop that is, also, featherable and reversable (optional) produced by Whirlwind Propellers which only costs $7500 and is made in America. We feel a 3 blade is best for our pusher needs (among other benefits) for a 2 blade is blanked by the fuselage and strakes when it goes horizontal. Only one blade will be blanked on a 3 blade prop by the fuselage and strakes when it goes horizontal. This prop is carved from 68 plys of hardwood laminates by a precision duplicating machine, wrapped in carbon for even more structural strength, and 75% of the prop leading edge (from the tip) has a stainless steel leading edge bonded on to protect the prop from rain and bug erosion. The blades are then installed into a stock certified Mac Cauley hub. Whirlwind has over 10 years of experience carving custom props and testing prop airfoils at the Reno Air Races on Formual 1 racing planes - they have the best blade airfoils and the composite blade construction down to a science. Many of their props are already flying on airshow demonstration aircraft, Glasairs, etc. Whirlwind's phone #, address and Point Of Contact (POC) is: Jim Rust 1860 Joe Crosson Drive, #H El Cajon, CA 92020 (619) 562-3725<< HTH. Infinity's Forever, EAA Member EAA Technical Counselor JD EAA Flight Advisor AOPA Member Test Pilot James D. Newman, President LCDR F-14 USNR INFINITY Aerospace Mailing Address: P. O. Box 12275 El Cajon, CA 92022 Shipping Address: 1750 Joe Crosson Drive, D-2 El Cajon, CA 92020 (619) 448-5103 PH & FAX 72124.347@compuserve.com OR INFINITY_Aerospace@compuserve.com Home Page http://ourworld.compuserve.com/homepages/INFINITY_Aerospace Date: Fri, 3 Jan 1997 21:32:56 -0500 From: INFINITY Aerospace <72124.347@compuserve.com> Subject: COZY: Re: Constant Speed Prop Hi Eric, >I called these folks last fall and at that time they had nothing in production and told me there was nothing in the works for a pusher, but if someone ordered one, they might have time to put something together.< I just talked to Jim Rust, owner of WhirlWind Propellers (his shop is just down the street 1/4 mile). They are now making a 3 blade pusher prop for a Cirrus customer. They might be looking for someone who is flying to test 2 and 3 blade props for canards. >I also remember them telling me if they did, the estimated weight would be 60 to 70 pounds. If something has changed since then, I would like to know, but after talking with them, I was disappointed.< The 80" diameter 3 blade props he was talking about at that time last fall do weigh about 60 to 70 pounds - these props with counter weights are used on acrobatic show planes - you don't need counter weights. A 2 blade prop for canards will weigh about 40 pounds, the 72" diameter prop that I'm interested in will weigh about 50 to 55 pounds. WhirlWinds Home Page is: http://www.concentric.net/~wwpc HTH. Infinity's Forever, JD From: "campbell" Subject: COZY: New Prop/ Engine combination? Date: Mon, 27 Jan 1997 23:23:03 I was talking to a friend who is currently building a Velocity. He mentioned that the factory is test flying a Franklin with a new 3 blade cockpit adjustable prop from Ivo. TO roll is said to be reduced by a factor of 2. Max cruise is not changed much, but they still have some fine tuning to do. Cost is reputed to be $1500 and the weight is "only a couple of pounds" more than a fixed pitch prop. They're not sure if it will stand up to the IO360 normally used in the Velocity, but works well with the Franklin 6. Any body else know anything about this? Date: Tue, 28 Jan 1997 07:41:13 -0800 From: Wayne Lanza <"wlanza@iu.net@wlanza"@iu.net> Subject: COZY: Velocity/Franklin/Ivo Prop Combination In the past, I committed to writing a report on the Ivo Prop. To date, the Franklin powered Velocity has well over 50 hours logged with the in-flight adjustable Ivo Prop. There is another prop being evaluated by a builder in N.Carolina (I think..) that is bolted up to a Lycoming IO360. That effort is underway and is of yet to reach a conclusion that I am aware of. The Velocity guys are really happy with the prop and I need find out about the N.C. stuff. I spoke with Ivo recently and he seems to be very open and enthusiastic about his product. I am very close to the people at Velocity and depending upon thier findings, (all positive so far), will probably use an Ivo on my O320 powered MK3. The hold up with this prop on an IO360 is due to some mods to strengthen the blade attachment to the hub. As I understand it, the violence of the Lyc 360's firing impulse was enough to loosen the original blade attachments. This has been supposedly remedied & hence the N.C. experiments. Realize, this is not my idea of a report! I still intend to write one, which will be copied to the news groups & letters. Take Care & Safe Flying, Wayne Lanza Date: Sat, 1 Feb 1997 23:19:05 -0500 (EST) From: SWrightFLY@aol.com Subject: Re: COZY: Prop Extension & Props The prop is probably the single best point of performance improvement with the EZ type aircraft. Something like the I-VO I feel is the future. Velocity says it cuts the take-off distance by 50% ----I wonder if they will continue to perform safely after 800 or 900 hours??????? Date: Sat, 1 Feb 1997 22:22:17 -0700 (MST) From: Ron Lee Subject: Re: COZY: Prop Extension & Props At 23:19 97/2/01 -0500, you wrote: >The prop is probably the single best point of performance improvement with >the EZ type aircraft. Something like the I-VO I feel is the future. Velocity >says it cuts the take-off distance by 50% ----I wonder if they will continue >to perform safely after 800 or 900 hours??????? > This sounds like snake oil to me. :) Does anyone have validated performance data that would justify one brand of prop over another, or specific prop size/pitch info? It is also desirable to understand how the prop selection is affected by density altitude. I live at 7000' so take-off performance is very critical, especially in the summer. Ron lee Date: Sun, 2 Feb 1997 11:05:31 -0500 (EST) From: SWrightFLY@aol.com Subject: Re: COZY: Prop Extension & Props I have flown over 1000 hours in 11 years in an EZ with several props (Teds, Bruce Tifts, and one I made myself) --- my speed would vary by about 6% @ altitude with prop changes. Klaus S. in CA. has one of the most "efficient" props but are expensive. The I-VO prop has had a lot of bad press----has it been justified? I have more questions than answers. Where are the prop "experts"? Date: Sun, 2 Feb 1997 11:30:24 -0500 From: Rick Roberts <102503.1561@compuserve.com> Subject: COZY: Prop Performance Do anybody know of an excellent program that calculates prop performance that will analyze above 200 HP (say 250 +)? Rick Roberts It getting close to time to order the prop. Date: Mon, 3 Feb 1997 00:05:26 -0500 (EST) From: Allegro816@aol.com Subject: COZY: Ivo props. At an airshow last year I spoke with a builder who had questions about the Ivo prop and was able to get some documented information from the Canadian DOT, who it was said had incidents of prop failure on record. Perhaps this would help. I myself am not a prop expert, but I have put a 300 hours on one of Performance's props and found it smooth and very durable, i.e. it ate a fuel cap and took me home safely. I get indicated speeds in excess of 200mph routinely at 26-2750rpms. Robin du Bois Cozy 22AZ Allegro Avionics (Engine monitors) From: "Steve Campbell" Subject: COZY: Props Date: Mon, 3 Feb 1997 13:26:25 perhaps this is repeating the obvious, but the key here is that Velocity is flying the Ivo prop with the six cylinder Franklin. The power pulses are far less severe than in an IO-360 or even an O-360. As a result the prop has been able to perform well (to date) in a pusher configuration. I have the "luxury" of waiting another 1-2 years before I will be picking a prop/engine combination. If I were doing it now however, the ability to use a low cost, cockpit adjustable prop would present a big advantage for the Franklin, particularly if TO performance is a key figure of merit in your application. Steve **************************************** Stephen A. Campbell Associate Professor, EE University of Minnesota ***************************************** From: Epplin_John_A@hpmail1.90.deere.com Date: Mon, 3 Feb 97 09:44:41 -0600 Subject: COZY: Props There was a posting somewhere last year concerning someone's experience with a electric adjustable composite prop. It seams that on the first takeoff, the prop began making noises and vibrating. The pilot reduced power to the min needed for a go around and landed. The story I heard was that the prop was junk after this one flight. This was on some EZ type aircraft. The reason was supposedly flexing of the blades caused by the disturbed air flow through the prop. This caused heat which allowed more flexing causing more heat, a runaway condition. I don't believe this was an IVO prop but am not sure. I don't want to upset anybodys apple cart, but this seems like it could be a problem with flexible props. I hope the details can be worked out because of the positive things that can come from this type of arrangement. No blade bearings etc. to spend big bucks on. In my humble opinion, any airplane that pushes the 200 MPH speed should have some form of variable pitch prop, it is quite a spread from takeoff to cruise. I don't like the weight and price of the conventional hydraulic props, must be something better out there. John Epplin, Mk4 #467, building wings. Date: Mon, 03 Feb 1997 14:01:14 -0500 From: "JEFF S. RUSSELL" Organization: AEROCAD INC. Subject: Re: COZY: Props Epplin_John_A@hpmail1.90.deere.com wrote: > > There was a posting somewhere last year concerning someone's experience with a > electric adjustable composite prop. It seams that on the first takeoff, the > prop began making noises and vibrating. The pilot reduced power to the min > needed for a go around and landed. The story I heard was that the prop was junk > after this one flight. This was on some EZ type aircraft. The reason was > supposedly flexing of the blades caused by the disturbed air flow through the > prop. This caused heat which allowed more flexing causing more heat, a runaway > condition. I don't believe this was an IVO prop but am not sure. I think this was Doug Koster's Cozy MKIV. He tried an IVO and it was sent back to them the next day after his first and only flight. He was just glad to get on the ground safely!!! Jeff/AeroCad, Inc. From: Epplin_John_A@hpmail1.90.deere.com Date: Mon, 3 Feb 97 13:32:18 -0600 Subject: COZY: Props > perhaps this is repeating the obvious, but the key here is that Velocity is > flying the Ivo prop with the six cylinder Franklin. The power pulses are > far less severe than in an IO-360 or even an O-360. Thanks Steve, also Jeff R. I am at least a year away to making a commitment on engine and prop. I hope by this time the IVO or some similar type proves it will work. Am keeping my eyes and ears open toward the Franklin also. Anybody have any recent words from Nat on his Franklin experience? Apparently Velocity is having good results. John Epplin Mk4 #467 Date: Mon, 3 Feb 1997 21:17:39 -0500 (EST) From: SWrightFLY@aol.com Subject: Re: COZY: Props A Warp drive prop split at the hub during the first flight on George Walters 160 HP Long- EZ. He was able to get it back to the runway OK but with a lot of vibration. George sent it back for a full refund. Warp drive has been "working" on a fix for high HP pushers for the past 2 years but as far as I know at this time --No fix has been made. I hope they are still working on the "fix" as we need a good vari-pitch pusher prop. Date: Tue, 4 Feb 1997 04:02:13 -0500 (EST) From: SMilesCozy@aol.com Subject: Re: COZY: Props In a message dated 97-02-03 19:15:10 EST, you write: << Ok maybe I'm not up with the latest technology .... whats the difference between a low cost, cockpit adjustable prop and a regular constant speed prop (other than the low cost?). >> Allan, The simplest way to explain it is that a CS prop maintains the same RPM (speed), regardless of where you have the throttle positioned, through the use of a governor....an adjustable prop's pitch can be changed in flight but the speed (RPM's) will still change with a change in throttle setting. Hope this helps, Steve Miles Cozy MkIV 272 From: "Steve Campbell" Subject: COZY: Props Date: Tue, 4 Feb 1997 09:17:48 >The simplest way to explain it is that a CS prop maintains the same RPM >(speed), regardless of where you have the throttle positioned, through the >use of a governor....an adjustable prop's pitch can be changed in flight >but the speed (RPM's) will still change with a change in throttle setting. I find this to be an interesting thread. I hope that you will bear with me for one more response. Cockpit adjustable props are electrically rather than hydraulically driven. According to my second hand information - I'm sure that someone will correct me if I am wrong - Weight Cost Cockpit adjustable adds 2-5 lbs adds ~$1000 Constant speed adds ~25 lbs adds ~$6000 Due to their location, true constant speed props often present significant W/B problems for canard aircraft. Tim Merrill indicated that the only reason that he put one in (and used an O-320 to compensate for the added weight), was because he happened upon a very good deal for the combination. He said that he would not recommend it in general due to the high cost. Also CS props require an engine that is set up for using them. I've never had one, but I believe that they require a hollow crank to transmit the fluid to the governor. **************************************** Stephen A. Campbell Associate Professor, EE University of Minnesota ***************************************** Date: Tue, 04 Feb 1997 10:54:07 -0500 From: kevin@ias.com (Kevin R. Walsh) Subject: COZY: C.S. Props or Cockpit Adjustable OK, now being relatively ignorant on this subject, I am jumping in with a question also. If a cockpit adjustable prop is not, in the strictest definition, constant speed, why can't it be? It seems to me that if you have control over the pitch, you should be able to put a tachometer and the pitch adjustment together to arrive at a control system that keeps constant RPM without regard for throttle setting, which would be a "constant speed prop." No? Kevin R. Walsh Mechanical Engineer Intelligent Automation Systems 149 Sidney Street Cambridge, MA 02139 TEL 617.354.3830 FAX 617.547.9727 Date: Tue, 4 Feb 1997 11:22:02 -0500 (EST) From: SWrightFLY@aol.com Subject: Re: COZY: Props Don't forget the $$$ difference in the two. A Hoffman CS 3 blade pusher prop for a 160 HP Lic. will cost $10,000 new. If you want to buy a used one (just rebuilt) for $7500.00 I have one for sale in Nashville. A cockpit adjustable like the IVO prop will cost $2000.00 The Hoffman is certified for pushers while with the IVO.....you take your chances.. but not because its not certified ....just because it hasn't spent a lot of hours pushing an EZ around so we are not sure it will last! From: Lee Devlin Subject: Re: COZY: C.S. Props or Cockpit Adjustable Date: Tue, 04 Feb 1997 9:41:32 MST Kevin wrote: > OK, now being relatively ignorant on this subject, I am jumping in > with a question also. If a cockpit adjustable prop is not, in the > strictest definition, constant speed, why can't it be? It seems to > me that if you have control over the pitch, you should be able to put > a tachometer and the pitch adjustment together to arrive at a control > system that keeps constant RPM without regard for throttle setting, > which would be a "constant speed prop." No? My understanding is that these props have a climb and cruise setting with no intermediate positions. This is much simpler to accomplish than a feedback control system which must be tuned for each prop/engine. In addition to monitoring the rpm, a feedback/control system should know the pitch setting which would require a position encoder of some sort. Also, the actuator needs plenty of power to react to sudden changes in load, otherwise it will behave sluggishly which will make it seem more like an adjustable prop rather than a constant-speed prop. The electric motor would have to be sized larger to react to sudden changes in load/input. The motor couldn't have a simple DPDT switch with limits switches, instead you'd need a large H-bridge and PWM driver circuit. and the associated controlling circuitry. It might be a fun project for someone so inclined, but the simplicity of a cruise/climb setting gets you about 95% of the benefit of a constant speed prop so it's difficult to justify the additional expense of a speed controller. Lee Devlin Date: Tue, 04 Feb 1997 09:01:47 -0800 From: Michael Antares Subject: COZY: CS vs CA A very interesting thread... Being by trade and occupation right now a control systems engineer I appreciate the comments of Lee Devlin and agree with the requirements he has outlined. HOWEVER...these are all very handleable (new word!) and are the issues that come up with any servo-controlled system. I think it would be a very interesing project to turn a cockpit adjustable prop into a constant speed one (with LOTS of protection built in) and probably save quite a bit of money. Michael 6077 Old Redwood Highway Penngrove CA 94951 707.664.1171 Cozy#413 Finished through chap 14 except chap 13. Chaps 16 & 24 mostly finished. Now on chap 19 and 20. One wing/winglet finished, working on second. by SERV05.SLAC.STANFORD.EDU (PMDF V5.1-4 #16063) with SMTP id <01IF0IIGR1IA002TLW@SERV05.SLAC.STANFORD.EDU> for cozy_builders@hpwarhw.an.hp.com; Tue, 4 Feb 1997 09:56:00 PST Date: Tue, 04 Feb 1997 09:56:15 -0800 From: hrogers@SLAC.Stanford.EDU (Howard Rogers) Subject: Re: COZY: C.S. Props or Cockpit Adjustable Just to add another data point of clarification to this discussion: The method of motivation is not relevant to whether the prop is "constant speed" or "cockpit adjustable". It can be electric AND constant speed. It can be hydraulic AND cockpit adjustable (but not constant speed). In fact it can be manually cockpit-adjustable through a direct linkage. All of these things have been done. The most traditional method in use now, for constant speed props, is through the use of a governor, which employs spinning counterweights that act against a spring (called the speeder-spring) to control a simple spool-type valve which sends engine oil through the crank to the prop hub. Moving the prop-control-lever acts directly on the speeder-spring to change the position the counterweights stabilize at, for any given RPM. I, for one, would be delighted if a simple, two-position, manually adjustable pusher prop were available for use with the O320 for my Long EZ. What the heck, might as well make it suitable for an O360 for all you Cozy guys, and I'll have that much more safety margin!. It is a very tall order, however, to make one that will stand up to the beating a prop gets in the dirty aerodynamic pulses behind a pusher airplane, AND is light enough to be manageable for CG considerations. I'm not holding my breath, but I am hopeful. I am also too much of a chicken to be pioneer. I will buy one when there is a LOT of time in service accumulated by someone braver than I. --Howard Rogers, A&P 2005148 From: garfield@pilgrimhouse.com (Garfield) Subject: Re: COZY: C.S. Props or Cockpit Adjustable Date: Tue, 04 Feb 1997 18:54:48 GMT Organization: Pilgrim House On Tue, 04 Feb 1997 9:41:32 MST, Lee Devlin wrote: >My understanding is that these props have a climb and cruise setting >with no intermediate positions. Um, no this is not correct. The IVO cockpit adjustable DOES have infinitely adjustable setting. What you do is set your min & max pitch limits on the ground, and then the controls will allow you to vary between the two, but you CAN set it to anything in between these two limit stops. Practically speaking, though, you are probably running at either of the two stops; still, though, the infinite adjustability does allow some nice experimention capabilities. For example, you could set the stops a bit beyond what you expected. Then experiment at either end, one at a time, e.g. to get your best TO roll and climb, come back down and lock in that pitch stop. Then go back up, hunt around for best cruise, and return to lock in that second stop (landing carefully, heh, since your climb performance at that setting is not gonna be so grand). In talking to Ron @ IVO, he suggests people set their cruise pitch to give them no less than a 200'/min climb margin. That way, if the electrics fail, the prob is stuck in a pitch you can probably live with for a divert. Nice concept; I would think constant SPEED is only really a second-order need, either for acro (there, it's a must have, but still a very small percentage of folks) or if you really wanna be cushy and insist on the equivalent of cruise control (another sorta small percentage of folks, I would guess...correct me if I'm wrong here). But inflight adjustable seems like a tremendously big win for a very large percentage of folks. And it sure is a LOT cheaper than constant speed. Whew, way cheaper. Garfield Date: Tue, 04 Feb 1997 11:03:45 -0800 From: Allan Aaron Subject: Re: COZY: Props Steve Campbell wrote: > prop/engine combination. If I were doing it now however, the ability to > use a low cost, cockpit adjustable prop would present a big advantage for > the Franklin, particularly if TO performance is a key figure of merit in > your application. Ok maybe I'm not up with the latest technology .... whats the difference between a low cost, cockpit adjustable prop and a regular constant speed prop (other than the low cost?). Is the cockpit adjustable prop electrically activated? Does it work like a CS prop? How do the costs compare? Thanks Allan Aaron Date: Tue, 4 Feb 1997 14:29:09 -0500 (EST) From: Westlande@aol.com Subject: Re: COZY: C.S. Props or Cockpit Adjustable In a message dated 2/4/97 6:01:11 PM, hrogers@SLAC.Stanford.EDU (Howard Rogers) wrote: >It is a very tall >order, however, to make one that will stand up to the beating a prop gets >in the dirty aerodynamic pulses behind a pusher airplane, AND is light >enough to be manageable for CG considerations. Howard, That's what I found out. While looking for "the solution", I found that the MT "light" props for pushers had operational restrictions for O-320's in the 2450-2650 rpm range for continuous operation. The standard MT did not, but was quite a bit heavier. Maybe it can be done, but I did not find one. As an aside, I have become friends with Greg Bastin, who has been flying his 3 place for several years in Australia with an electrical CS prop made by a fellow in New Zealand. Greg liked the prop, but became frustrated with the service, so he just ordered an MT. He may have it on by now. When he was discussing the specifics with Michael at MT, he strongly recommended Greg go with a two blade prop instead of a three blade, which he ended up doing. Eric Westland by InfoAve.Net (PMDF V5.1-5 #17060) with SMTP id <01IF12KTHRGG959HIU@InfoAve.Net> for cozy_builders@hpwarhw.an.hp.com; Tue, 4 Feb 1997 19:30:32 EST Date: Tue, 04 Feb 1997 19:30:32 -0500 (EST) Date-Warning: Date header was inserted by InfoAve.Net From: Nick Ugolini Subject: Re: COZY: Props > If you want to buy a used one (just >rebuilt) for $7500.00 I have one for sale in Nashville. A cockpit adjustable >like the IVO prop will cost $2000.00 The Hoffman is certified for pushers >while with the IVO..... AirCraft Spruce's latest catalog lists the Ivo inflight adjustable prop at 9 lbs (3 blade 72"). Cost for a 64-72", 2 blade is $690, the 3 blade is $790. Spare blades are about $120. Damage a blade.... fix the prop. I have damaged two prop in the past, and only side of the prop really was messed up. You still have to replace the whole dog gone thing...... I just paid $675 for a wood prop with a steel leading edge...... bummer. I love flying a constant speed prop. Next time...... Nick Ugolini unick@mail.charleston.net Varieze N89RS LongEZ N29TM Cozy Mark IV #0264 Date: Wed, 5 Feb 1997 13:05:09 -0500 (EST) From: SMilesCozy@aol.com Subject: Re: COZY: C.S. Props or Cockpit Adjustable In a message dated 97-02-04 11:01:10 EST, you write: << It seems to me that if you have control over the pitch, you should be able to put a tachometer and the pitch adjustment together to arrive at a control system that keeps constant RPM without regard for throttle setting, which would be a "constant speed prop." No? Kevin R. Walsh >> Yes, given those circumstances it would be a "constant speed" prop. I think the fly in the ointment would be the interface between the tach and the prop pitch control. I understand that the standard issue M1A1 Brain can and has handled the chore quite well. :^) With proper management, Increasing pitch while increasing throttle, decreasing throttle before decreasing pitch, and using manifold pressure and RPM to control power, it is "constant speed" only you're the governor. It's just not a set it and forget it type of control. Steve Miles Cozy MkIV 272 Date: Thu, 06 Feb 1997 08:06:37 From: RSiebert1@gnn.com (Reid Edward Siebert) Subject: Re: COZY: Prop Extension >I am getting ready to purchase a prop extension ( I am planning on using >a 3 blade performance prop). Here is the question: Should I order >threaded or unthreaded drive lugs? The flywheel on my engine has 3/4" >drive lugs tapped for a 1/2" bolt. I assume that I should order an >extension with basically the same thing (3/4" tapped lugs). Why do they >offer unthreaded lugs anyway? Mark, Give Judy Saber a call (Woofter-Saber Manuf.) and discuss your prop extention needs with her. She will happily, and expertly, answer all your questions concerning mating any prop to any engine. After all, that's what she does for a living, and she does it very well! Phone: 954-436-9496 Fax: 954-436-0015 Mention my name, we're old friends. Reid Siebert Cozy Mk.IV #221 A&P Mechanic From: "Krasa, Paul" Subject: RE: COZY: Prop Extension Date: Thu, 6 Feb 1997 13:16:32 -0500 >---------- >From: RSiebert1@gnn.com[ > > > >>I am getting ready to purchase a prop extension ( I am planning on using >>a 3 blade performance prop). Here is the question: Should I order >>threaded or unthreaded drive lugs? The flywheel on my engine has 3/4" >>drive lugs tapped for a 1/2" bolt. I assume that I should order an >>extension with basically the same thing (3/4" tapped lugs). Why do they >>offer unthreaded lugs anyway? > > >Mark, > > Give Judy Saber a call (Woofter-Saber Manuf.) and discuss your prop >extention needs with her. She will happily, and expertly, answer all your >questions concerning mating any prop to any engine. After all, that's what >she does for a living, and she does it very well! > >Phone: 954-436-9496 Fax: 954-436-0015 > >Mention my name, we're old friends. I agree. Just got a prop extension from Judy. She does beautiful work and is extremely knowledgable. I wouldn't buy an extension from anybody else. Paul Krasa > > > with SMTP id <01IF6JBH418U95XXST@InfoAve.Net> for cozy_builders@hpwarhw.an.hp.com; Sat, 8 Feb 1997 17:24:06 EST Date: Sat, 08 Feb 1997 17:24:06 -0500 (EST) Date-Warning: Date header was inserted by InfoAve.Net From: Nick Ugolini Subject: COZY: IVO Props I contacted IVO props and have the following info: 2 bladed prop $1740 3 bladed prop $1960 Replacement blades are $220. Wiring installation kit is $33.20 (breaker, wire, switches) Wire to the prop is 2- #16 wires. (they reverse the polarity). An 0235 would use a 62" 3 blade or a 68" 2 blade An 0320 would use a 68" 3 blade The pitch is adjustable from 30-90" Apparently Spurce is advertising the adjustable prop for the smaller rotax engines at $700, not our larger engines. Nick Ugolini unick@mail.charleston.net Varieze N89RS LongEZ N29TM Cozy Mark IV #0264 Date: Wed, 12 Feb 1997 16:13:43 -0500 (EST) From: Westlande@aol.com Subject: COZY: Wood props, High HP >From time to time I cruise the RV Archives. Today I ran across a copy of a letter from Lycoming that dealt with wood props on 160+ hp engines. It was part of a larger discussion on harmonic balancers. I thought some of you may be interested. Eric Westland +++++++++++++++ TEXTRON Lycoming 652 Oliver Street Williamsport PA 17701 April 22, 1994 Mr Greg Rainwater 2518 80th PL SE Everett WA 98203 Dear Greg: Your letter of April 6, 1994, to our Customer Service Department regarding harmonic dampers for wooden propellers and Lycoming O-320 and O-360 engines was forwarded to me for reply. Mr. LANDOLL's statement regarding a wooden propeller's inability to absorb the vibratory pulses from a reciprocating aircraft engine is contrary to anything I have ever seen or heard in the past. Rather, I believe that the wood fibers tend to absorb vibratory inputs from an engine. Further, this supposed failing is not the reason for certificated aircraft to not be equipped with wooden propellers; it is more as you suspect - a happenstance of the market. Perhaps most pilots with aircraft of 160 horsepower or more do not want the hassle of having to re-torque their propellers on a regular schedule. As a check on my initial response to your letter I checked with Sensenich Propeller. Their people told me that they sell many wooden propellers to homebuilders using Lycoming O-320 and O-360 engines from 160 through 200 horsepower. For 180 and 200 horsepower installations they require an adapter that gives an 8 inch diameter contact surface to increase the area over which the attaching load is spread. Obviously I have assumed that you were referring to fixed pitch wooden propellers. There are some manufacturers of constant speed props who use aluminum hubs and wooden composite blades. Two that come to mind are Hoffman and MT. Both are German companies, but both have sold in the US. Lycoming has determined satisfactory crankshaft torsional vibration characteristics with some of these propellers on 160 through 200 horsepower engines. TEXTRON Lycoming Reciprocating Engine Division allows the use of wooden, fixed pitch propellers on its engines of 160 through 200 horsepower. No particular type of propeller is specifically recommended. I trust that this will answer your questions in regards to the subject. Very truly yours, TEXTRON Lycoming Reciprocating Engine Division R. B. Schreckengast Project Engineer Date: Tue, 18 Mar 1997 18:53:42 -0500 (EST) From: SWrightFLY@aol.com Subject: Re: COZY: Props Does anyone have any recent information on the performance of the Vari-pitch I-VO prop or any vari pitch props on EZ type aircraft. Velocity seems to be having good results with it on the Franklin powered Velocity. I plan to do a lot of prop research at Sun & Fun. I would like to do some homework before I go. Any input will be appreciated. Steve Wright Wright Aircraft Works LLC Date: Thu, 8 May 1997 17:16:17 -0400 From: wilhelmson@scra.org Subject: Re: COZY: Franklin/Ivoprop FOR builders interested in the IVO prop on a Lycoming. I talked to the IVO people about using the IVO on my 0320 and here is what I found out. The electrical brush contact system for controlling the pitch motor is a much bigger problem on a LYC than on a Franklin because of the front mounted starter and alternator drive wheel. They have designed a large insulated copper ring that bolts to the wheel and a long bracket that holds the brushes and bolts to the top of the engine case. The wires from the brush ring must get inside the prop hub. At the time I talked to them they were a little hazy on how this was going to happen. In fact the man said "If you can build a airplane you should be able to figure out how to do it". On the Franklin they use a insulated ring between the prop or the extension and the crank flange. The wires go down through the insulated ring. It appears like they have not worked it out yet. The IVO prop is very interesting because it solves the pitch changing mechanism problem in a very simple way. It also eliminates the high stress concentration shoulder on the prop blade hub that has been the failure point on all constant speed props including the certified ones. My one negative observation is that the prop blades are very thin at the hub and only the outer 30% of the prop changes pitch. This maybe quit acceptable if the three blades are made larger in area to make up for it. Props are such a critical item that I hesitate to buy a one that is not fully proven. I am definitely chicken when it comes to props, but I really hope that the IVO prop proves out. From: jan-erik.synnerman@lf.se Date: Wed, 13 Aug 1997 10:31:29 +0100 Subject: COZY: Propeller for Long EZ and Cozy III Hello everybody, My friend uses a Prince P-tip 62x74 propeller for his Long EZ=2E Engine is=20= =20 a 150 hp O-320=2E With statics at 2700 rpm and 140 kts cruise he is =20 obviously under-propped=2E Does anybody know what dia and pitch numbers he=20= =20 should order for a new Prince? Are there other brands that are better? =20 I=B4m soon going to order a prop for my new Cozy III wich makes the answers= =20 interesting for me too=2E Jan Erik Synnerman, Stockholm, Sweden =20 Date: Wed, 13 Aug 1997 15:29:35 +0200 From: morten@scandisoft.no (morten scandisoft.) Organization: ScandiSoft AS Subject: Re: COZY: Propeller for Long EZ and Cozy III jan-erik.synnerman@lf.se wrote: > = > Hello everybody, > My friend uses a Prince P-tip 62x74 propeller for his Long EZ. Engine i= s > a 150 hp O-320. With statics at 2700 rpm and 140 kts cruise he is > obviously under-propped. Does anybody know what dia and pitch numbers h= e > should order for a new Prince? Are there other brands that are better? > I=B4m soon going to order a prop for my new Cozy III wich makes the ans= wers > interesting for me too. > = > Jan Erik Synnerman, Stockholm, Sweden I have ordered propellor from Chris Lodge Propellors in London for my Cozy MKIII. He is a full time propellor-man and is approved under Popular Flying Assosiation in UK. Price is GBP 385,- for 63x63 inch white cover wood with metal leading edge for O-235 engine. Cozy-driver David Machin in London recommended this to me and is using both three-bladed and 2-bladed propellor on his Cozy MK III from Chris Lodge Propellors. He told me he was very satisfied, and he knows Chris Lodge personally. David has an O-320 150 hp in his Cozy. I can relay info on pitch diam. etc if You are interested. David gave me a ride in his Cozy a week ago out of Biggin Hill, London. GREAT STUFF ! =2E.. By the way, I'm approx 30 days from first T/O after rebilding. Brgds Morten Brandtzaeg, Norway From: AlWick@aol.com Date: Tue, 2 Sep 1997 14:51:08 -0400 (EDT) Subject: COZY: Prop diam I notice the instructions for the MKIV say 70" max. What prop diam are most people using? Am I right that the only significant concerns are adequate ground clearance and tip speed? Sure would appreciate your input. thanks -al wick Date: Fri, 05 Sep 1997 14:17:12 -0700 From: "LCDR James D. Newman" Organization: INFINITY Aerospace Subject: COZY: Constant Speed Props Hi Steve and All, >. . . and will add an extra 25-45 lb in the rear where you don't need it, < WhirlWinds new carbon blade constant speed propellers are only 25 lbs. to 35 lbs., depending on HP. Call Jim Rust at (619) 562-3725. Infinity's Forever, JD Date: Fri, 05 Sep 1997 14:17:12 -0700 From: "LCDR James D. Newman" Organization: INFINITY Aerospace Subject: COZY: Constant Speed Props Hi Steve and All, >. . . and will add an extra 25-45 lb in the rear where you don't need it, < WhirlWinds new carbon blade constant speed propellers are only 25 lbs. to 35 lbs., depending on HP. Call Jim Rust at (619) 562-3725. Infinity's Forever, JD Date: Mon, 08 Sep 1997 10:51:33 +0200 From: Jean-Jacques CLAUS Subject: COZY: Variable propeller with only 2 positions Hi to all, I don' t remember where i red something about a variable propeller with only 2 pitch position ( take off / landing + cruise ). Does anyone have some informations and/or experience about a similar propeller solution ? Thanks for your reply, Jean-Jacques CLAUS Aix-en-Provence - FRANCE Cozy Classic #CC1056 Date: Sun, 5 Oct 1997 06:36:34 -0400 From: Eddie Vann <100740.3723@compuserve.com> Subject: COZY: Prop Search I have been flying my Long-Ez for six years and it has been a great source of pleasure to me and certainly worth the 3000 plus hours of building. Keep at it you builders, it really is worth it. I still fly with the original, great, prop built by Great American Propellor but I have cleaned up the Aircraft aerodynamically and increased engine power and I would now like to fit a new prop, indentical except for a little more pitch so as to be able to open the throttle fully at altitude without the engine speed exceeding 2600/2650 rpm. Great American has unfortunately gone out of business and Bruce Tifft, who measured my prop and was going to build me a new one, has gone. Another builder recommended by Rutan was Ted Hendrikson, I think in the Pacific Northwest. Can anyone put me in touch with him, if he is still in business, or another maker of good performing, multi-laminate wood props? I'm afraid that my efforts to find the equivalent here in Europe have been unsuccessful. Thanks, Eddie Vann Long-Ez F-PGEV From: "McElhoe, Bruce" Subject: RE: COZY: Prop Search Date: Mon, 06 Oct 97 10:10:00 HST I have been flying my Long-Ez for six years and it has been a great source of pleasure to me and certainly worth the 3000 plus hours of building. Keep at it you builders, it really is worth it. I still fly with the original, great, prop built by Great American Propellor but I have cleaned up the Aircraft aerodynamically and increased engine power and I would now like to fit a new prop, indentical except for a little more pitch so as to be able to open the throttle fully at altitude without the engine speed exceeding 2600/2650 rpm. Great American has unfortunately gone out of business and Bruce Tifft, who measured my prop and was going to build me a new one, has gone. Another builder recommended by Rutan was Ted Hendrikson, I think in the Pacific Northwest. Can anyone put me in touch with him, if he is still in business, or another maker of good performing, multi-laminate wood props? I'm afraid that my efforts to find the equivalent here in Europe have been unsuccessful. Thanks, Eddie Vann Long-Ez F-PGEV I am flying with one of Ted's props, a 62 x 66 that is perfect for my little O-235 in a Long-EZ. The prop is well made, and beautifully finished. My only criticism is that the white paint he uses on the tips chips easily, but that's not important to me. I'm sure he can work with you to give you the performance you want. His address is Ted Hendrixson 600 Superior Street Concrete, Washington 98237 Phone 360-853-9847 Bruce McElhoe L-EZ N64MC Date: Sat, 13 Dec 1997 15:36:00 -0500 From: David Domeier Subject: Re: COZY: Re: [canard-aviators] Props and Engines Nigel, I trust the following preliminary report on the Velocity accident is the one you are referring to re a 3 blade prop: Did it have an IVO prop? NTSB Identification: ATL98FA017 Accident occurred NOV-26-97 at FLORENCE, SC Aircraft: MARK EWART VELOCITY STANDARD RG, registration: N907ME Injuries: 4 Fatal. On November 26, 1997, about 1544 eastern standard time, a Mark Ewart Velocity Standard RG, homebuilt airplane, N907ME, collided with trees and the ground during a forced landing near Florence, South Carolina. The airplane was operated under the provisions of Title 14 CFR Part 91, and visual flight rules [VFR]. Visual meteorological conditions prevailed. A VFR flight plan was filed, but not activated, for the personal flight. The private pilot and three passengers were fatally injured, and the airplane was substantially damaged. The flight originated at Lantana, Florida, about 0850, on the same day. A refueling stop was made at Savannah, Georgia, with departure from Savannah at an undetermined. time. The flight departed Savannah, then returned, following the pilot's report of an undefined problem. Subsequently, the flight departed again. The pilot requested VFR flight following as it over flew Florence. About 12 miles northeast of Florence, the pilot stated he had a problem and requested vectors to the nearest airport. Vectors were provided by Florence Air Traffic Control Tower toward the Florence airport. During the vectors to Florence, the pilot stated that the engine had quit. The airplane collided with trees and the ground about one mile north of the Florence Airport. Initial examination of the airplane revealed that one blade of the three bladed propeller was absent from the hub. It was not located at the accident site. Date: Sat, 13 Dec 1997 16:05:42 -0500 (EST) From: Nigel Field Subject: COZY: Re: [canard-aviators] Props and Engines At 01:45 PM 12/13/97 -0500, you wrote: >[The Canard Aviators's Mailing list] >Reports on here about experience with Ivoprops do not inspire a great >deal >of confidence. Warp Drive are still restricted to Subaru or Rotax - no >Lycomings yet. Are there any other in flight adjustable props that do >not >cost two arms and two legs? >A deathly hush seems to have fallen on the Superior Millenium Lycoming >engine kits. Anybody have any idea what's going on there? I tried a small Ivo electric controllable pitch 3 blade on my Subaru EA-81 in my VE about 4 years ago. It lasted one short circuit. Blades were very hot and badly delaminated at the roots from flexing, surprized they all stayed on. Report is filed with EAA and was included in those posted earlier. Last June a good friend here in Ottawa CA was flying a NSI CAP electric variable pitch 3 blade when at 1.5 hrs total time a blade came off in cruise flight. He totaled his Lancair 0-235 in the forced landing that resulted, but he was not injured. NTSB lab analysis showed severe cracking of the remaining 2 aluminum blade root retention collars. This was the first one on an 0-235. He has writen about it on RAH and will be posting a full report shortly. Have read enough other horror stories about IVO including the latest fatal Velocity crash which may or may not have been a prop failure but looks like it at this point, to stay well clear of any variable pitch props. Use a bigger engine and a good fixed pitch. Its cheaper and probably lighter and certainly safer IMO. There is an Internet movement quietly getting underway to get builders organized to report on failures like this and on other bad products on the market. It will be maintained by a respected Lawyer (PHd) and hombuilder who will be screening all submissions for accuracy and possible slander to avoid stupid law suit threats. It is hoped to be up and running in the near future on a web page, then builders can read about this stuff and make their own decisions. It is indeed unfortunate (IMO) that our beloved EAA can't or wont, provide this kind of service, but don't get me going on that issue. Nigel Field Vari-eze C-GMEZ Date: Sun, 14 Dec 1997 15:45:14 -0500 From: Jim Hocut Subject: Re: COZY: Re: [canard-aviators] Props and Engines >>Have read enough other horror stories about IVO including the latest fatal >>Velocity crash which may or may not have been a prop failure but looks like >>it at this point, to stay well clear of any variable pitch props. >> I just talked to a Velocity builder today about this accident. He's using a Subaru engine w/ Ivo variable pitch prop, and was concerned enough to talk directly to Dwayne Swing to try to get some facts. What I heard was that this pilot/builder had just reinstalled the prop without using a torque wrench. When advised that it needed to be properly torqued he just said something to the effect that he could get the bolts tight enough. I'm sure there will be more come out about this, but based on what I've heard I'm not going to write off the Ivo due to this one incident. However, I've also got the "luxury" of being 3 to 4 years away from flying so that I can wait 'till there's plenty of good history on this product before making a decision. Jim Hocut jhocut@mindspring.com Date: Mon, 15 Dec 1997 11:06:27 +0200 From: Rego Burger Subject: Re: COZY: Re: Props and Engines >>I think that's a little bit strong, I don't here these sort of things about McCaully or Hartzel props. I think you get what you pay for.<<< someone said, Sorry can't keep quite on this one. 2yrs ago fellow aeroclub landed C210 on golf course..hole in one on the 17th...reason...one blade said auto feather for me buddy! A pin or something had sheared off! A few months ago another C210 had the same problem shortly after T/O father and son on board. Sad mistake he tried to turn back ... father crawled out - 11yr old son burned fatal. Both reported severe vibration with a loss of power even though the motor still ran.... Moral. People have a tendency to be "happy" with a "certified" thing packing up as they enjoyed the security of knowing and paying for someone to have checked to see if it were safe from production to maintenance level. NOW when an EXPERIMENTAL thing goes...oooo! O.K. we all know how cheap a certified VP prop is now don't we. For the cost/performance ratio it's a wood prop for me thanks. I could go through about 5 wood props in the time it would take me to pay for a VP anyway. My opinion... not trying to change anyone ...just reporting... the big guys have their problems too, I think they have a way of keeping it quiet! Rego CZ4#139 RSA Date: Mon, 15 Dec 97 9:13:46 EST From: "Nick J Ugolini" Subject: Re: COZY: Re: [canard-aviators] Props and Engines From: "Jim Hocut" , on 12/14/97 3:45 PM: >>Have read enough other horror stories about IVO including the latest fatal >>Velocity crash which may or may not have been a prop failure but looks like >>it at this point, to stay well clear of any variable pitch props. >> For what its worth, I was in Savannah last week for a class, and parked at Savannah Air. Talked to the same attendant that helped the owner of the Velocity. He told me the guy was having problems with the engine/prop. Used their tools to work on the engine, and on the prop (including a torque wrench). Engine cowl off, on, adjust this and that, flew around the pattern testing things.....but he WAS messing with the prop. He had recently built the plane, and was HIGHLY upset. Yelling at his wife and girls. The attendant made a comment to me that he and the rest of the FBO felt the owner should not have been flying in his state of mind (irreguardless of the plane). He HAD to get home for thanksgiving.. My buddy (a CFI) also was in Savannah and watched his activities and ravings. Talked at length with the girls and wife. Really shook him up..... Bottom line is: planes rarely just quit, unless you run out of gas, or the prop rips itself apart (happened on my plane, landed on a road). There are usually little warning signs first. Heed your intuition, and dont hesitate to rent a car if you feel there is a problem. by post.larc.nasa.gov (8.8.6.1/pohub4.2) with SMTP id KAA03963; Mon, 15 Dec 1997 10:08:35 -0500 (EST) Date: Mon, 15 Dec 1997 09:46:23 -0500 From: Paul Krasa Subject: Re: COZY: Re: Props and Engines Just to add to the fire. A Defiant builder put constant speed props on his aircraft. Burt Rutan told the builder the rear prop will fail due to the loads placed upon it from the design configuration. The only approved prop is a wooden prop for all the Rutan aircraft. The reason, I understand, is because of the "blank spot" when the prop is in the horizontal position. This accounts for the chopping noise that a canard makes with a two blade prop. A three blade prop decreases the sensation because only one blade goes through horizontal at a time, but the effect on the blade is the same. The blade is unloaded then loaded momentarily twice per revolution. This results in a high cyclic rate on the blade. Thus, just like bending a paper clip back and forth, cyclic fatigue will occur. As for carbon props. Carbon fiber is highly susceptible to low velocity impact damage which can cause subsurface fiber breakage which is not detectable visually. The reason for the damage is as the shock wave travels through the structure it imparts shear loads upon the fiber causing breakage due to the extremely low shear modulus of carbon fiber. Like any material, carbon fiber has its strength, high modulus of elasticity, and its weakness, low modulus of shear. In the world of materials, there are no panaceas. I would NOT use a carbon fiber prop on a Pusher. Worrying about stuff going through a wooden prop is bad enough. Paul Krasa Long EZ 214LP At 11:06 12/15/97 +0200, Rego Burger wrote: >>>I think that's a little bit strong, I don't here these sort of things >about >McCaully or Hartzel props. I think you get what you pay for.<<< >someone said, > >Sorry can't keep quite on this one. > >2yrs ago fellow aeroclub landed C210 on golf course..hole in one on the >17th...reason...one blade said auto feather for me buddy! A pin or >something had sheared off! > >A few months ago another C210 had the same problem shortly after T/O >father and son on board. Sad mistake he tried to turn back ... father >crawled out - 11yr old son burned fatal. >Both reported severe vibration with a loss of power even though the >motor still ran.... > > >Moral. > >People have a tendency to be "happy" with a "certified" thing packing up >as they enjoyed the security of knowing and paying for someone to have >checked to see if it were safe from production to maintenance level. > >NOW when an EXPERIMENTAL thing goes...oooo! > >O.K. we all know how cheap a certified VP prop is now don't we. > >For the cost/performance ratio it's a wood prop for me thanks. I could >go through about 5 wood props in the time it would take me to pay for a >VP anyway. > >My opinion... not trying to change anyone ...just reporting... the big >guys have their problems too, I think they have a way of keeping it >quiet! > >Rego >CZ4#139 >RSA > > > > From: wilhelmson@scra.org Date: Mon, 15 Dec 1997 10:21:46 -0500 Subject: Re[2]: COZY: Re: Props and Engines My experience with certified constant speed props is that they also have many failures and EXPENSIVE problems. I flew a hi performance single (Commanche) for 15 years and many other light twins and singles with constant speed props. They invariably were the least reliable item on the airplane. The average time on any one prop overhaul or removal on my Commanche was 200 hrs. Most of these removals were due to ADs, none of them were due to strikes or other damage. After all the most important feature of any flight critical item on a airplane, regardless of cost, is RELIABILITY. If you don't agree with this, fine. But don't carry passengers especially ones you care for. Date: Mon, 15 Dec 1997 20:14:08 -0500 (EST) From: Nigel Field Subject: Re: COZY: Re: Props and Engines At 09:46 AM 12/15/97 -0500, you wrote: > >As for carbon props. Carbon fiber is highly susceptible to low velocity >impact damage which can cause subsurface fiber breakage which is not >detectable visually. The reason for the damage is as the shock wave >travels through the structure it imparts shear loads upon the fiber causing >breakage due to the extremely low shear modulus of carbon fiber. Well maybe so, but there are lots of carbon over wood props flying on Ez's. Mike and Dick just went around the world on 2 of them, Berkut uses them plus thousands of warp drives on tractor installations. > >Like any material, carbon fiber has its strength, high modulus of >elasticity, and its weakness, low modulus of shear. In the world of >materials, there are no panaceas. I agree, carbon is very attaractive due it high tensile strength, about 450,000 PSI depending on brand and what material it started life from (ie nylon) plus the quality of layup. I have never made and tested one from carbon so can't offer any first hand experience. Its great for prop tips however as they can be kept thin and stiff for high efficiency. I have been doing that for 8 years with excellent results and no problems whatsoever. As for a carbon over wood prop, I have been thinking about trying one more as an experiment, but considering the added cost of carbon for a small change in weight it is not really economical, just like our aiplane structures. Also it will not flex as well as glass so the designed in blade twist under load might reduce its performance. Nothing wrong with E glass IMO, its plenty strong for this job. > >I would NOT use a carbon fiber prop on a Pusher. Worrying about stuff >going through a wooden prop is bad enough. See above re all the guys doing it quite succesfully. BTW Dick Rutan had a Harzel CS prop on his 0-360 Long eze for a short while but took it off and went back to a FP, although I don't know why, but he must have had a good reason. Perhaps his brother cut off a blade one night with a chain saw, he thought them very dangerous on an EZ -:) . Plus they are heavy, expensive and a maintenance headache, as Jack Wilhelmson posted. Nigel Field Date: Tue, 16 Dec 1997 09:32:53 +0100 From: blecoq Subject: COZY: Props and Engine That letter to add up on the subject We have in France the homebuilt design called ORION. This is a very nice pusher design close to the Cirrus VK3 configuration but smaller.It was designed as a four seater. Jacques GRINVALDS, the designer, died following the crash of his airplane quite a few years ago.The main reason for this was that he had fitted a constant speed prop to it. Due to the high stresses involved,one of the blades departed the hub in flight resulting extreme vibrations modes which induced the loss of flight controls and subsequently the crash . Looks like we should be very cautious in choosing one of the most vital item of our bird not to say to keep a bit of conservatism ( at least initially). I also take a chance to wish a Merry Christmas and happy building and flying year to all Cozy builders and their family for 1998. On my side I am hoping 1998 will be THE flying year but you never know. Beno=EEt LECOQ by m5.boston.juno.com (queuemail) id VtA19408; Thu, 18 Dec 1997 21:39:54 EST Subject: COZY: your Prop? From: mbeduhn@juno.com (Mark W Beduhn) Date: Thu, 18 Dec 1997 21:39:54 EST --------- Begin forwarded message ---------- From: "Neal Newman" Hi Mark the plane looks great... I noticed the 3 bladed Wood prop.. who makes it?.. how do you like it? and what was the cost of it? --------- End forwarded message ---------- Neal, I bought my prop from Performance Propellers (520) 394-2059. This is the same prop that Nat had on his plane when I visited him last April. I forgot the name of the guy who owns the company, but I have talked to him several times and he is great to work with. The prop is excellent and I am very satisfied with it. There is only a 300 rpm difference between static and full speed. I have to send it back to get the final finish and rain guard, but I can't get myself to take it off the plane (I'm having too much fun!). Although the prop is expensive ($1800 or so), I don't think about it when I'm going 200+ mph with low noise and vibration. Mark Beduhn Cozy IV N494CZ (60 hours and climbing)