---------------------------------------------------------- Zenith-List Digest Archive --- Total Messages Posted Fri 02/23/07: 27 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:29 AM - Re: Top Window, Bubble Doors and Windshield on 701 (Jeffrey A Beachy) 2. 06:32 AM - Re: CH701 Landing Lights (ROBERT SCEPPA) 3. 06:42 AM - Re: 801 Bottom Fuselage Skin (Dave Ruddiman) 4. 07:08 AM - Re: CH701 Landing Lights (Dino Bortolin) 5. 07:47 AM - Engines (Robert Schoenberger) 6. 09:04 AM - Re: Engines (LarryMcFarland) 7. 09:06 AM - Re: 701 engine choices (Zed Smith) 8. 09:49 AM - Re: Engines (Dennis Shoup) 9. 10:14 AM - Re: Engines (Chuck Deiterich) 10. 11:00 AM - Re: Top Window, Bubble Doors and Windshield on 701 (Peter Dolamore) 11. 11:35 AM - Re: Engines (PatrickW) 12. 11:52 AM - Re: sealing fuel senders (japhillipsga@aol.com) 13. 12:46 PM - Re: Engines (billmileski) 14. 12:48 PM - Re: Engines (Bryan Martin) 15. 12:57 PM - Re: Engines (billmileski) 16. 12:57 PM - Re: Engines (Paul Mulwitz) 17. 01:00 PM - Re: sealing fuel senders (Dave Ruddiman) 18. 01:40 PM - Re: CH701 Landing Lights (billmileski) 19. 01:58 PM - Re: Re: CH701 Landing Lights (Craig Payne) 20. 02:01 PM - navaid servo installation (alex_001) 21. 02:16 PM - Re: 1st Hundred Hours of Building (XL) (Clyde Barcus) 22. 04:37 PM - Re: 1st Hundred Hours of Building (XL) (JAPhillipsGA@aol.com) 23. 05:06 PM - 701 Jury Struts (Mike Hoffman) 24. 06:29 PM - Re: CH701 Landing Lights (Tommy Walker) 25. 08:26 PM - Re: 1st Hundred Hours of Building (XL) (Bill Naumuk) 26. 10:28 PM - Re: Engines (N601RT) 27. 11:33 PM - Zenair News (Ian McClelland) ________________________________ Message 1 _____________________________________ Time: 05:29:26 AM PST US Subject: Zenith-List: RE: Top Window, Bubble Doors and Windshield on 701 From: Jeffrey A Beachy Some answers to your questions. Hopefully helpful. 1. What is the top window made of, plexiglass or lexan? How about the windshield? Bubble doors? ans: The top window is made of lexan its tough in that it won't crack easy but it will scratch easy. The windshield is plexiglass and will crack easy. Make sure to use the special drill bits to go thru both of them though. You can drill through the lexan/plexiglass right into the tubing by the way with these bits. The bubble doors are plexiglass so be careful drilling also. For cutting plexiglass I used a hand grinder with a fiberglass disc. Cutting the lexan, I scored it with a utility knife and straight edge and snapped the peices off. 2. The plans call for rivets for the top window. With all the talk of cracking lexan or plexiglass, is it wise to use screws instead of rivets? ans: The lexan is very tough and the rivets work fine. You can use screws but most of the installations I've seen are rivets. No cracking at all. I did both installations this past summer in 95 deg weather without issues. I'd be careful working in cold weather with the windshield. My garage is so cold now that I don't even want to look at the project. 3. Is the idea of the diagonal stiffener 7F12-3 to put a bow in the top window? ans: Yes it puts a bow in the top to keep it from flopping around, and tightens it up. It looks good also. 4. Has anyone used some type of weatherstripping or silicone between the window and the upper tubes to keep out water? ans: I used silicone on the side tubes but it just squeezes out to the sides of the tube. The window sits on the top of the tube which does not give a goood surface for silicon. A very thin weather strip would be better or nothing at all since the wing root will cover this area when installed. I would say most of the leakage will occur at the front corners around the windshield/front wing mounts. I will use a cover when its outside. 5. It seems like the rivets at the front upper tube/cabin frame connection will put pressure on the top window, since the cabin frame and rivets are higher than the upper tubes. The same goes for the back gusset, though the plans call for that area to be cut out. ans: This is an area where the instructions do not give any info. Since the cabin frame to the tubes is an important structural area, I did not rivet thru the lexan into the tubes here. At the front, just set the top window on top of the rivets and rivet thru the side tubes only, a little bowing or pressure but it doesn't matter. 6. What about silicone or weatherstripping for the front windshield? Roger at Zenith says his 701 leaks pretty badly during rain. Has anyone managed to keep the water out? ans: I shopped around for the channel and got some useless stuff. I finally got some from Wicks or Spruce that worked great. It makes the windshield look very nice. The stuff they use on the Czec 701's is really nice but I couldn't find it anywhere. 7. the list archives show that some have used the rubber channel 05-01500 from ACS for the windshield. How did you fasten the channel? ans: I will look thru my receipts and see if I can get the part number I used but that sounds familiar. I used polyzap from Tower Hobbies to fasten the channel to the windshied. I would recommend using very fine sandpaper on the windshield to roughen it up a bit where the channel contacts it inside and outside. This will allow the polyzap to bond better. Run a thin line inside the channel and install it quickly, and don't cut the channel to exact size before, trim it off at the ends after installation. This is one of those moments of high stress to not get the stuff all over the windshield. After the windshield was screwed down I ran a line of weather stripping adhesive under the channel where it contacts the airframe. 8. Is there any problem with installing the top window, bubble doors and front windshield before installing the wings? ans: I hope not because I installed mine. You can tape poster board on the top window while installing the wing root to keep from damaging it. Jeff, I'll post the pics I have of this installation right away on my website http://701builder.com so you can get an idea of what I did at least. The site is still under construction, its more of a photo essay of what I have done, and I'll be adding descriptions of work later. I'll try to get it up there in the morning. It will be under the category fuselage. Making a website is definately time consuming. Hope some of this helps for now. Brian ________________________________ Message 2 _____________________________________ Time: 06:32:19 AM PST US From: ROBERT SCEPPA Subject: Re: Zenith-List: CH701 Landing Lights > How about in the nose bowl? --- Ken Arnold wrote: > Listers, > > I am going to install a ldg light on my 701. The > most obvious attachment location is the bracket > connecting the landing gear bow. However, there are > some lights available that might fit in the forward > slat. Xevision has one measuring about 4"Wx4L"x2"H. > Has anyone installed a light in their slats? > > Thanks in advance, > > Ken Arnold > Building CH701 QB Kit; target completion May 2007 Cheap talk? ________________________________ Message 3 _____________________________________ Time: 06:42:52 AM PST US From: "Dave Ruddiman" Subject: Re: Zenith-List: 801 Bottom Fuselage Skin I understand the concept of lightness. I was one of the original members building 13 Neiuport 11's at our EAA chapter. ----- Original Message ----- From: Gary Gower To: zenith-list@matronics.com Sent: Thursday, February 22, 2007 11:52 AM Subject: Re: Zenith-List: 801 Bottom Fuselage Skin Sorry for the late answer, but I am very slow reasding my mail, lots of work. I read from Graham Lee (Neiuport 11 Replicas): "Only add Lightness and Simplicity to any airplane you are building" Saludos Gary Gower 701 912S 100 hrs just like plans... Dave Ruddiman wrote: Larry, I was planning on using .025 because that's what most of the rest is. I'm not disputing your suggestion but, why .020 instead of .025? Do you have any idea why the thinner material on the belly where it seems like it would need the protection? Thanks, Dave ----- Original Message ----- From: "LarryMcFarland" To: Sent: Monday, February 05, 2007 5:14 PM Subject: Re: Zenith-List: 801 Bottom Fuselage Skin > > Dave, > I'd take the .016 piece and lay it over a piece of .020 (not .025) and use > it for a template. .016 is noisy until you've got > lots of paint on it. > > Larry McFarland - 601HDS at www.macsmachine.com > do not archive > > Dave Ruddiman wrote: >> I know this has come up for some of the other ZAC planes, but when I took >> the bottom fuselage skin for my 801 out of the box I discovered that it >> is .016. I just assumed it would be .025. It seems like it should be >> heavier given the kind of use the plane was designed for. Any thoughts, >> anyone? >> Dave in Salem > > > > > > > > ------------------------------------------------------------------------- --- Don't pick lemons. See all the new 2007 cars at Yahoo! Autos. ________________________________ Message 4 _____________________________________ Time: 07:08:05 AM PST US From: "Dino Bortolin" Subject: Re: Zenith-List: CH701 Landing Lights There is a benefit to having the lights on the wing, or at least somewhere where you can see the light during flight; if you encounter icing conditions, the ice is much easier to see. You'll be able to see a reflection from the ice on the adjacent surfaces. Dino On 2/23/07, ROBERT SCEPPA wrote: > > > How about in the nose bowl? > > --- Ken Arnold wrote: > > > Listers, > > > > I am going to install a ldg light on my 701. The > > most obvious attachment location is the bracket > > connecting the landing gear bow. However, there are > > some lights available that might fit in the forward > > slat. Xevision has one measuring about 4"Wx4L"x2"H. > > Has anyone installed a light in their slats? > > > > Thanks in advance, > > > > Ken Arnold > > Building CH701 QB Kit; target completion May 2007 > > > Cheap talk? > > ________________________________ Message 5 _____________________________________ Time: 07:47:41 AM PST US From: Robert Schoenberger Subject: Zenith-List: Engines List . . . please be patient while I ask a bunch of probably dumb questions re engines for my 701. I always thought I would use a Rotax 912 - 80 HP, but an awful lot of my buddies in my flying club are down on Rotax due to the continual AD's (is that the right word?). I also see a lot of service notices in the EAA mags. This sort of surprises me since they have been around a long time, and one would think the bumps would be smoothed out. First dumb question - why do all of these engines for LSA and ultralites operate at such a high RPM, i.e. in the 5,000 RPM range? I assume this 5,000 RPM range has some sort of gearbox. What are typical prop RPM's at cruise? If I'm not mistaken the engines which powered the Aeronca, Taylorcraft, PIper Cub and the like were about 65 HP and were direct drive. Why aren't such engines available for the 701, or are they? Wouldn't these be much quieter (I"m big on quiet)? Those old classic birds just seemed to putt putt along. My Piper Dakota of some years ago operated in the 2,400 range. Has anyone tried a 60HP HKS in a 701? I've heard nothing but good things about the HKS's. Are cowlings and FWF packages available? I've been impressed with the low 2 - 3 gph fuel consumption of these engines. Would the 701 fly ok with 60 HP? It's my understanding that the 701 was originally designed for something like 55 HP, but I may be wrong about this. Any other thought you might have will be appreciated. Thank you. Robert Schoenberger 701 60% ________________________________ Message 6 _____________________________________ Time: 09:04:44 AM PST US From: LarryMcFarland Subject: Re: Zenith-List: Engines Robert, I share your concern with the Rotax engines. They are the most popular, but I'd be reluctant to use one because of company attitude and continuous "AD" notes. The latest requiring a waterless coolant didn't resolve a problem, but does acknowledge one. I'd have preferred they found a better fix. Most re-drives are nearly 2 to1, but 5000 rpm is only a number at which the peak HP is developed and it doesn't create more than the problem with having a re-drive in the first place. There are smaller engines that would perform just as well on a 701 and the HKS would, but for its light weight, is extremely reliable and well proven on trikes. Don't think a FWF kit is available at this time. The trend of putting the largest engine possible on these light Zeniths fails to realize the value of a "light aircraft". I'd also consider VW or the GEO aircraft conversions or Suzuki conversion engines. See link, http://www.ultralightnews.com/sunfun2000/ravenredrivesnf.htm. You might possibly find a Cont A-65 or a 75 hp Franklin that's available. Good engines! Simple! Somewhat Rare, as are some parts! Larry McFarland - 601HDS at www.macsmachine.com Robert Schoenberger wrote: > > > List . . . please be patient while I ask a bunch of probably dumb > questions re engines for my 701. I always thought I would use a Rotax > 912 - 80 HP, but an awful lot of my buddies in my flying club are down > on Rotax due to the continual AD's (is that the right word?). I also > see a lot of service notices in the EAA mags. This sort of surprises > me since they have been around a long time, and one would think the > bumps would be smoothed out. > > First dumb question - why do all of these engines for LSA and > ultralites operate at such a high RPM, i.e. in the 5,000 RPM range? I > assume this 5,000 RPM range has some sort of gearbox. What are typical > prop RPM's at cruise? > > If I'm not mistaken the engines which powered the Aeronca, > Taylorcraft, PIper Cub and the like were about 65 HP and were direct > drive. Why aren't such engines available for the 701, or are they? > Wouldn't these be much quieter (I"m big on quiet)? Those old classic > birds just seemed to putt putt along. My Piper Dakota of some years > ago operated in the 2,400 range. > Has anyone tried a 60HP HKS in a 701? I've heard nothing but good > things about the HKS's. Are cowlings and FWF packages available? I've > been impressed with the low 2 - 3 gph fuel consumption of these > engines. Would the 701 fly ok with 60 HP? It's my understanding that > the 701 was originally designed for something like 55 HP, but I may be > wrong about this. > > Any other thought you might have will be appreciated. Thank you. > Robert Schoenberger 701 60% > > ________________________________ Message 7 _____________________________________ Time: 09:06:37 AM PST US From: Zed Smith Subject: Zenith-List: Re: 701 engine choices do not archive Robert, This may not answer any of your questions.....probably just add flames to an already hot topic. Obviously, like airframe choices, the selection of an engine is partly a personal issue and partly dictated by constraints imposed by the design. The 701 originally had a 65 HP 2-stroke Rotax. As builders began wanting/demanding more speed/performance from basically a slow, high-drag design, the 912 in the 80 HP configuration was offered. You can now install a turbo-charged R912 boasting 115 horses. The Vne hasn't changed. I would guess somebody will attempt to install a turboprop, maybe a PT-6, as soon as they figure out how to handle the engine weight. The 701 will not outrun an RV. If you need speed you don't need a 701. I'm not aware that Continental or Lycoming still builds the earlier engines you mention.....therefore parts, etc, aren't available everywhere. This may be a possible hinderance to current builders. Engine speed: That's the choice of the designers. In order to insure that prop tips remain sub-sonic reduction arrangements are used. Some use internal gearing, some use external belts. Again, the desgn philosophy. Recall that Riceburners (Japanese-made motorcycles) turn some really high RPMs and use a reduction arrangement. They usually call this a transmission. ADs: In the automotive world they're called "recalls". In the Cover-Your-Rear aviation world it is AD. An AD is a fact of life; goes with the territory. An AD is part of the price of flying. Nobody likes this, but, like the sunrise, it happens on a regular basis. Just get up early and crow at the dawn.....then go flying. Some "hangar flying" involves myths......or the truth stretched a bit. The Rotax 912 uses a "dry sump" arrangement for lubrication; somewhat akin to old radial engines. Some years ago Rotax changed the oil tank dipstick to address an oil level issue. Markings on the new stick differed from the original to insure proper oil level. No problem.....except that somehow this dipstick-change story circulated enough times that it became a "Rotax 912 engines use a lot of oil" tale. Not true; oil consumption has nothing to do with the dipstick, but if you repeat a story enough times it takes on a mantle of "truth". ( Oh, if you fail to put the dipstick back in place then oil might blow out the hole. Now that IS oil consumpion! ) Putting strips of aluminum foil in the hubcaps on your car will foil radar speed traps. Now that's a truth! There are thousands of Rotax-powered craft flying. Probably wouldn't be if there were a serious defect. Likewise with other brands/makes of engines. Sort of like buying ScotchBrite pads.......pay your money and take your chances; some are the wrong color. If you have the opportunity to attend the Rotax factory-sponsored engine school it will be time well spent. None of the above addressed your serious questions, but possibly it will bring out the flamethrowers. Been too quiet lately. Best Regards, Zed/701/R912/90.xxx%/do not archive, again ________________________________ Message 8 _____________________________________ Time: 09:49:18 AM PST US From: "Dennis Shoup" Subject: Re: Zenith-List: Engines The HKS is also geared and develops max power at around 6,000 rpm. On 2/23/07, LarryMcFarland wrote: > > > Robert, > I share your concern with the Rotax engines. They are the most popular, > but I'd be reluctant to use one because of company attitude and > continuous "AD" notes. The latest requiring a waterless coolant didn't > resolve a problem, but does acknowledge one. I'd have preferred they > found a better fix. Most re-drives are nearly 2 to1, but 5000 rpm is > only a number at which the peak HP is developed and it doesn't create > more than the problem with having a re-drive in the first place. There > are smaller engines that would perform just as well on a 701 and the HKS > would, but for it's light weight, is extremely reliable and well proven > on trikes. Don't think a FWF kit is available at this time. The trend of > putting the largest engine possible on these light Zeniths fails to > realize the value of a "light aircraft". I'd also consider VW or the GEO > aircraft conversions or Suzuki conversion engines. See link, > > http://www.ultralightnews.com/sunfun2000/ravenredrivesnf.htm. > > You might possibly find a Cont A-65 or a 75 hp Franklin that's > available. Good engines! Simple! Somewhat Rare, as are some parts! > > Larry McFarland - 601HDS at www.macsmachine.com > > Robert Schoenberger wrote: > > > > > > List . . . please be patient while I ask a bunch of probably dumb > > questions re engines for my 701. I always thought I would use a Rotax > > 912 - 80 HP, but an awful lot of my buddies in my flying club are down > > on Rotax due to the continual AD's (is that the right word?). I also > > see a lot of service notices in the EAA mags. This sort of surprises > > me since they have been around a long time, and one would think the > > bumps would be smoothed out. > > > > First dumb question - why do all of these engines for LSA and > > ultralites operate at such a high RPM, i.e. in the 5,000 RPM range? I > > assume this 5,000 RPM range has some sort of gearbox. What are typical > > prop RPM's at cruise? > > > > If I'm not mistaken the engines which powered the Aeronca, > > Taylorcraft, PIper Cub and the like were about 65 HP and were direct > > drive. Why aren't such engines available for the 701, or are they? > > Wouldn't these be much quieter (I"m big on quiet)? Those old classic > > birds just seemed to putt putt along. My Piper Dakota of some years > > ago operated in the 2,400 range. > > Has anyone tried a 60HP HKS in a 701? I've heard nothing but good > > things about the HKS's. Are cowlings and FWF packages available? I've > > been impressed with the low 2 - 3 gph fuel consumption of these > > engines. Would the 701 fly ok with 60 HP? It's my understanding that > > the 701 was originally designed for something like 55 HP, but I may be > > wrong about this. > > > > Any other thought you might have will be appreciated. Thank you. > > Robert Schoenberger 701 60% > > > > > > > > > > ________________________________ Message 9 _____________________________________ Time: 10:14:41 AM PST US From: "Chuck Deiterich" Subject: Re: Zenith-List: Engines My direct drive Jabiru 2200 works just fine. Chuck D. N701TX ----- Original Message ----- From: "Robert Schoenberger" Sent: Friday, February 23, 2007 9:41 AM Subject: Zenith-List: Engines > > List . . . please be patient while I ask a bunch of probably dumb > questions re engines for my 701. I always thought I would use a Rotax > 912 - 80 HP, but an awful lot of my buddies in my flying club are down > on Rotax due to the continual AD's (is that the right word?). I also > see a lot of service notices in the EAA mags. This sort of surprises me > since they have been around a long time, and one would think the bumps > would be smoothed out. > > First dumb question - why do all of these engines for LSA and ultralites > operate at such a high RPM, i.e. in the 5,000 RPM range? I assume this > 5,000 RPM range has some sort of gearbox. What are typical prop RPM's > at cruise? > > If I'm not mistaken the engines which powered the Aeronca, Taylorcraft, > PIper Cub and the like were about 65 HP and were direct drive. Why > aren't such engines available for the 701, or are they? Wouldn't these > be much quieter (I"m big on quiet)? Those old classic birds just > seemed to putt putt along. My Piper Dakota of some years ago operated > in the 2,400 range. > > Has anyone tried a 60HP HKS in a 701? I've heard nothing but good > things about the HKS's. Are cowlings and FWF packages available? I've > been impressed with the low 2 - 3 gph fuel consumption of these > engines. Would the 701 fly ok with 60 HP? It's my understanding that > the 701 was originally designed for something like 55 HP, but I may be > wrong about this. > > Any other thought you might have will be appreciated. Thank you. > Robert Schoenberger 701 60% > > ________________________________ Message 10 ____________________________________ Time: 11:00:54 AM PST US From: "Peter Dolamore" Subject: RE: Zenith-List: Top Window, Bubble Doors and Windshield on 701 Jeff...I'm at the same point in the construction process..I've got some tinted .080" lexan for the top and was contemplating how best to seal it. I'm thinking maybe a thin automotive type rubber channel or something similar sitting on the edge of the door channel might work. I'm also thinking that ss screws / cup washers might work better..in one of the ZAC pics it show this so at some point I guess they thought it was good also ! Happy building..Peter in Ont. Canada. 80 % scratch built. >From: Jeffrey A Beachy >To: zenith-list@matronics.com >Subject: Zenith-List: Top Window, Bubble Doors and Windshield on 701 >Date: Thu, 22 Feb 2007 15:43:29 -0500 > > >I am ready to install my top window, Zenith bubble doors and the >windshield on my CH701. I have several questions for those who have >completed these tasks: > >1. What is the top window made of, plexiglass or lexan? How about the >windshield? Bubble doors? > >2. The plans call for rivets for the top window. With all the talk of >cracking lexan or plexiglass, is it wise to use screws instead of rivets? > >3. Is the idea of the diagonal stiffener 7F12-3 to put a bow in the top >window? > >4. Has anyone used some type of weatherstripping or silicone between the >window and the upper tubes to keep out water? > >5. It seems like the rivets at the front upper tube/cabin frame >connection will put pressure on the top window, since the cabin frame and >rivets are higher than the upper tubes. The same goes for the back >gusset, though the plans call for that area to be cut out. > >6. What about silicone or weatherstripping for the front windshield? >Roger at Zenith says his 701 leaks pretty badly during rain. Has anyone >managed to keep the water out? > >7. The list archives show that some have used the rubber channel 05-01500 >from ACS for the windshield. How did you fasten the channel? > >8. Is there any problem with installing the top window, bubble doors and >front windshield before installing the wings? > >Thanks in advance for your ideas. > >Jeff Beachy >CH701, 85% completed > > _________________________________________________________________ Your Space. Your Friends. Your Stories. Share your world with Windows Live Spaces. http://spaces.live.com/?mkt=en-ca ________________________________ Message 11 ____________________________________ Time: 11:35:24 AM PST US Subject: Zenith-List: Re: Engines From: "PatrickW" Scroll down to the bottom page of http://www.zenvair.com/ If you decide you are interested in further research with the Corvair engine, look at www.flycorvair.com - Patrick Read this topic online here: http://forums.matronics.com/viewtopic.php?p'906#96906 ________________________________ Message 12 ____________________________________ Time: 11:52:45 AM PST US Subject: Re: Zenith-List: sealing fuel senders From: japhillipsga@aol.com John, I used some red Permatex stuff that I have worried about ever since. I am building my RV-8 tanks right now and would recommend ProSeal for sealing in the sender unit. You can buy a pint and that should be more than enough for both tanks and they should not leak. Best regards, Bill of Georgia -----Original Message----- From: jdbutterfield@yahoo.com Sent: Thu, 22 Feb 2007 6:09 PM Subject: Zenith-List: sealing fuel senders hi list is the rubber gasket enough to seal the fuel sender housing, or should i put some sealer on the gasket. john butterfield 601XL, corvair torrance, ca ________________________________________________________________________ ________________________________ Message 13 ____________________________________ Time: 12:46:53 PM PST US Subject: Zenith-List: Re: Engines From: "billmileski" > First dumb question - why do all of these engines for LSA and ultralites > operate at such a high RPM, i.e. in the 5,000 RPM range? I assume this > 5,000 RPM range has some sort of gearbox. What are typical prop RPM's > at cruise? > > If I'm not mistaken the engines which powered the Aeronca, Taylorcraft, > PIper Cub and the like were about 65 HP and were direct drive. Why > aren't such engines available for the 701, or are they? Wouldn't these > be much quieter (I"m big on quiet)? Those old classic birds just > seemed to putt putt along. My Piper Dakota of some years ago operated > in the 2,400 range. The small displacement is for high volumetric efficiency (hp per displacement). Make a small displacement engine breathe well at high rpm to maintain torque, and inherit increasing hp with rpm. Small displacement equals low weight and small footprint. Regarding the fear of Rotax.. The service bulletin history reveals the most active closed-loop development process of all the engine manufacturers. Rotax addresses engine issues, maintenance procedures, storage issues, etc etc etc, down to the detail level (e.g. size of vent hole in coolant overflow bottle), because they have a huge number of engines, and a stable installation configuration. The "scary" bulletins are usually a proactive reaction to a small number of incidents. For example, there is a bulletin requiring mandatory inspection of cylinder bases for cracks. Lockwood Repair told me that this issue has only been seen by them (maybe the most experienced Rotax facility) in engines in towplanes seeing repeated, rapid heating and cooling (and I'm guessing all aircooled engines are at risk here too). A lot of the service bulletins are there to report upgrades (e.g. reporting new clamps to hold carb sockets in place that automatically keep the 8mm gap, to prevent overtightening by the end user, which was the cause of some carb self-removals). The 912S has the lowest prop speeds (5000rpm/2.43 57rpm) and matches the power-to-weight of any engine. Best floats or stol performance for 701. Regarding fuel economy, I see 3.2-3.5gph at 4600rpm cruise (cruise pitch). The HKS is better here, and this is probably a tie with the Jabiru, but the Jabiru requires 100LL, causing a 50% fuel cost addition. Fuel type: The 912S requires premium auto fuel. The HKS has a similar compression ratio (11.3:1) and will be no different. The Jabiru requires 100LL, and if you want to run 100LL this is a good choice -- the Rotax suffers reduced gearbox life if always using 100LL. There may be an issue with 10% ethanol in auto fuel and the Rotax, but I am expecting them to say it's okay. The Rotax is the LSA standard, with maintenance facilities adopting methods to deal with them, at a greater pace than other engines. Cessna chose it for LSA proof-of-concept. Also stand in the sidelines of the ultralight area at SNF, listen to the announcer talk about the planes as they take off.. "..powered by the Rotax 912S.." repeated as if a broken record. All Lycomings, Continentals, and Franklins, and Subarus, exceed the max engine weight limit listed on my 701 plans. Maybe the limit has been increased since I checked last, dunno. Rotax powered airplanes are very likely installed in a standard firewall-forward package provided by a kit manufacturer, with standard results. Insurance companies are most familiar with Rotax (of the non-certified engines). Rotax has a very stringent documentation practice in order to support a certified engine (installed on lots of certified aircraft, by the way), and we inherit some of the benefit in the uncertified engine. We get lots of detailed info on maintenance practices, operation in a variety of climates, etc. because of the wider variety of uses and conditions these omnipresent engines are exposed to. Speaking of climates, the Rotax operates nicely with 200F/200F oil/water temps in my 701, whether it's 95F or -10F outside, as long as I tape over the coolers more as the temperature drops. I am wondering how the aircooled engines manage. And you only have to run Evans waterless coolant if you want to push water temps to 260F, otherwise 50/50 standard coolant is fine, and it actually provides better heat removal due to its higer heat capacity. All the other engine manufacturers are dealing with their own design limitiations and review processes.. Jab with the cooling fin size changes and I think some valve train redesign, plus the current service bulletins on their web site..HKS with a total valve train redesign causing existing engines be replaced, the Subaru conversions with valve guide float and resultant growing pains.. I don't think you can assume their designs are happier just because their documentation is less feverish. Manufacturer of conversions are even more likely to be playing catch-up with problems with their designs. They are small shops with limited resources, and each installation by their customers is likely very unique. The rate of customer feedback regarding issues is much slower because of the lower number of fielded engines. Meanwhile Rotax is acquiring vast resources in the huge number of sales of these expensive engines, and further increasing their data gathering rate, and pumping more money into design improvements. I like the Jabiru, the installation is cleaner, the engine is beautiful, I just wanted the stol the plane could achieve with the higher efficiency of a longer prop at lower rpm, and the few extra hp of the 912S might provide a little extra too. The HKS is terrific, just forbids floats probably with only 60hp, and again stol suffers. Everything else was too heavy in my opinion for the 701. I flew into an airport to meet a friend (fellow builder) and the first words out of his mouth were "gee, I didn't hear you at all until you taxied up", and he was standing outside as I overflew at cruise power. I have made and received cell phone calls in the cockpit at cruise without a headset adapter (can neither confirm nor deny I was PIC at the time). The noise is similar to a C152. Definitely not excessive. In sum I would treat the active review process of the Rotax as a big advantage, it was one of the reasons I chose it. I would look a little closer at the service bulletins if you think you see a lot of "fear" issues there. And browse the NTSB database to get a feel for Rotax related failures before discounting what might be a very good overall choice for a 701. And none of the engines are perfect by any means. Bill Mileski Ledyard, CT Read this topic online here: http://forums.matronics.com/viewtopic.php?p'920#96920 ________________________________ Message 14 ____________________________________ Time: 12:48:27 PM PST US From: Bryan Martin Subject: Re: Zenith-List: Engines By running an engine at a high RPM, you can get the same power out of a much smaller and lighter engine, even though you lose some of the weight advantage because of the need for a speed reduction unit. The tradeoff is a bit more complexity and a few more moving parts. These engines actually tend to be quieter than direct drive engines because the higher frequencies produced fade out quicker over long distances (the high pitched whine can be irritating up close though). In any case, most of the noise produced by an airplane is from the propellor not the engine. Speed reduction can be helpful here by allowing you to run a large prop at a relatively low RPM. > > > First dumb question - why do all of these engines for LSA and > ultralites operate at such a high RPM, i.e. in the 5,000 RPM > range? I assume this 5,000 RPM range has some sort of gearbox. > What are typical prop RPM's at cruise? > -- Bryan Martin N61BM, CH 601 XL, RAM Subaru, Stratus redrive. do not archive. ________________________________ Message 15 ____________________________________ Time: 12:57:55 PM PST US Subject: Zenith-List: Re: Engines From: "billmileski" > All the other engine manufacturers are dealing with their own design limitiations and review processes.. Jab with the cooling fin size changes and I think some valve train redesign, plus the current service bulletins on their web site..HKS with a total valve train redesign causing existing engines be replaced, the Subaru conversions with valve guide float and resultant growing pains.. I don't think you can assume their designs are happier just because their documentation is less feverish. > Just to clarify -- the problems with the Jab and HKS referred to, are the old problems, not new ones. I meant to say "All the other engine manufacturers HAVE DEALT with their own design.." instead of "are dealing with". I don't want to imply that the Jab or HKS are undergoing major redesign, just that they did. Sorry for any confusion. Bill Mileski Ledyard, CT Read this topic online here: http://forums.matronics.com/viewtopic.php?p'923#96923 ________________________________ Message 16 ____________________________________ Time: 12:57:55 PM PST US From: Paul Mulwitz Subject: Re: Zenith-List: Engines Hi Robert, I have been following the responses to your engine questions, and noticed nobody seems to have answered your question about engine RPM being so high. There are two different kinds of engines used in airplanes: Ones that were designed for aircraft use and ones designed for another application that have been modified for aircraft use. The big limiting factor in aircraft is the limit imposed by propellers. A longer propeller generally works better than a shorter one, but propeller RPM is limited by the propeller length. As RPM increases, the speed of the propeller tip also increases according to simple geometry. As the propeller tip approaches the speed of sound it becomes inefficient, and if allowed to hit the speed of sound it can be destroyed. So there is a trade off between RPM and propeller length. Aircraft engines are designed to live with unusually low RPM limits because of the propeller trade off. Engines designed for other purposes tend to use much higher RPM that is limited by engine design issues rather than propeller issues. To become more compatible with propellers some sort of reduction gear or other reduction method is used to make the final RPM compatible with propellers. Many use a PSRU (Propeller Speed Reduction Unit?) while some others use belt and pulley approaches. In other cases, the engine is used in direct drive mode even though it is less efficient at the low RPM. It is easy to tell that a Corvair or Subaru or VW engine is converted from automobile use for airplane use. The Rotax is a little more difficult to guess. This line of engines was originally designed to operate snowmobiles and modified for aircraft use. It may well be that more Rotax engines are currently sold for aviation than snowmobile use, but that is their history. Good luck with your engine hunt. We all go through this since engines are a very significant part of the cost of a home built airplane. Paul XL Fuselage At 07:41 AM 2/23/2007, you wrote: > >List . . . please be patient while I ask a bunch of probably dumb >questions re engines for my 701. I always thought I would use a >Rotax 912 - 80 HP, but an awful lot of my buddies in my flying club >are down on Rotax due to the continual AD's (is that the right >word?). I also see a lot of service notices in the EAA mags. This >sort of surprises me since they have been around a long time, and >one would think the bumps would be smoothed out. > >First dumb question - why do all of these engines for LSA and >ultralites operate at such a high RPM, i.e. in the 5,000 RPM >range? I assume this 5,000 RPM range has some sort of >gearbox. What are typical prop RPM's at cruise? > >If I'm not mistaken the engines which powered the Aeronca, >Taylorcraft, PIper Cub and the like were about 65 HP and were direct >drive. Why aren't such engines available for the 701, or are >they? Wouldn't these be much quieter (I"m big on quiet)? Those >old classic birds just seemed to putt putt along. My Piper Dakota >of some years ago operated in the 2,400 range. >Has anyone tried a 60HP HKS in a 701? I've heard nothing but good >things about the HKS's. Are cowlings and FWF packages >available? I've been impressed with the low 2 - 3 gph fuel >consumption of these engines. Would the 701 fly ok with 60 >HP? It's my understanding that the 701 was originally designed for >something like 55 HP, but I may be wrong about this. > >Any other thought you might have will be appreciated. Thank you. >Robert Schoenberger 701 60% --------------------------------------------- ________________________________ Message 17 ____________________________________ Time: 01:00:40 PM PST US From: "Dave Ruddiman" Subject: Re: Zenith-List: sealing fuel senders I cut a sender hole in the wrong place in one tank, so I made a larger round metal patch, imbedded it in ProSeal I got from Van's and let it set. It held pressure for several days until I let the air out. I don't think it is called ProSeal anymore. The can says Flamemaster, but everyone still calls it ProSeal.I also built 2 RV9A tanks with it. Good Stuff. ----- Original Message ----- From: japhillipsga@aol.com To: zenith-list@matronics.com Sent: Friday, February 23, 2007 11:52 AM Subject: Re: Zenith-List: sealing fuel senders John, I used some red Permatex stuff that I have worried about ever since. I am building my RV-8 tanks right now and would recommend ProSeal for sealing in the sender unit. You can buy a pint and that should be more than enough for both tanks and they should not leak. Best regards, Bill of Georgia -----Original Message----- From: jdbutterfield@yahoo.com To: zenith-list-digest@matronics.com Sent: Thu, 22 Feb 2007 6:09 PM Subject: Zenith-List: sealing fuel senders hi list is the rubber gasket enough to seal the fuel sender housing, or should i put some sealer on the gasket. john butterfield 601XL, corvair torrance, ca ------------------------------------------------------------------------- ----- ________________________________ Message 18 ____________________________________ Time: 01:40:39 PM PST US Subject: Zenith-List: Re: CH701 Landing Lights From: "billmileski" Mine is on the underside of the cowling behind the oil cooler opening. It is an enclosed 55W driving light, with a built-in lens, and a reasonably aerodynamic enclosure. I've used it, but with the standard Rotax alternator, at lower rpm (descent and landing) I can't have radio, transponder, intercom, instruments, nav lights, strobes, and landing light on without watching my battery discharge. And this is while keeping the (incandescent Nu-Lite) instrument lights off. At least with the Rotax the battery is not involved in the ignition circuit, but it would be a drag if my radio dropped out at my towered home airport, due to reduced battery voltage. I say all this in case you have a Rotax. To do over I'd consider LED lighting. By the way, a friend of mine has some 3W LEDs which are pretty amazingly bright, bright enough to make a landing light from in quantity. Might be fun to mess with. Not sure of their price. Food for thought. Bill Mileski Ledyard, CT 701/912S Read this topic online here: http://forums.matronics.com/viewtopic.php?p'930#96930 ________________________________ Message 19 ____________________________________ Time: 01:58:38 PM PST US From: "Craig Payne" Subject: RE: Zenith-List: Re: CH701 Landing Lights >> To do over I'd consider LED lighting You can also drop the current consumption by using HID lamps. Expensive but possibly cheaper than redesigning your charging circuit: www.creativair.com www.xevision.com -- Craig ________________________________ Message 20 ____________________________________ Time: 02:01:23 PM PST US Subject: Zenith-List: navaid servo installation From: "alex_001" hello, can someone please help me with some pics or any other help and suggestions for installing navaid servo in my 601xl thank you Read this topic online here: http://forums.matronics.com/viewtopic.php?p'933#96933 ________________________________ Message 21 ____________________________________ Time: 02:16:20 PM PST US From: "Clyde Barcus" Subject: Re: Zenith-List: 1st Hundred Hours of Building (XL) Impressive! Clyde ----- Original Message ----- From: Rich To: zenith-list@matronics.com Sent: Monday, February 19, 2007 4:22 PM Subject: Re: Zenith-List: 1st Hundred Hours of Building (XL) I'm a above the 400 hours mark and am on the Fuselage sides. Wings done and Tail section done. Rich Simmons 601 XL ________________________________ Message 22 ____________________________________ Time: 04:37:16 PM PST US From: JAPhillipsGA@aol.com Subject: Re: Zenith-List: 1st Hundred Hours of Building (XL) Rich, remember it's not a race. You're okay to enjoy it more. Drink a few more adult beverages along the way, tell your wife how difficult the work is, etc. We have all convinced our spouses it may take years and years and thousands and thousands of dollars to get to where your at. Please keep this a secret or they will have us painting the porch ceiling, changing the oil in their car and mowing the lawn. Yeach ! Best regards, Bill of Georgia ************************************** AOL now offers free email to everyone. Find out more about what's free from AOL at http://www.aol.com. ________________________________ Message 23 ____________________________________ Time: 05:06:46 PM PST US Subject: Zenith-List: 701 Jury Struts From: "Mike Hoffman" I have my struts installed and now I am working on the jury struts. Using the dimension on the prints, the jury strut lower horizontal (500 mm long piece) does not work out if placed 1200 mm up from the center of the lower strut mounting hole (it is to long). In addition, if I used the given location, the jury strut angel brackets that are attached to the bottom of the wing would not intersect. It looks like I have a couple of options. One would be to shorten the lower horizontal piece and install it at the given location. I would have to remove and change the bend in jury strut angle. The other option (more favorable) would be to raise the location by about 40 to 60 mm and cut down the vertical and diagonal pieces of the remaining jury strut pieces. Has anyone else encountered this problem and if so, what changes did you make? It would be nice if there were a n assembly guide for this operation. Thanks in advance Mike H Read this topic online here: http://forums.matronics.com/viewtopic.php?p'968#96968 ________________________________ Message 24 ____________________________________ Time: 06:29:01 PM PST US Subject: Zenith-List: Re: CH701 Landing Lights From: "Tommy Walker" Take a look at this: http://www.ch701.com/builders/Steve%20Johnston/Steve_Mods.htm If I were going to install a landing light, I think I would do this.... Tommy Walker in Alabama N8701 92.31416....% complete [quote="arno7452(at)bellsouth.net"]Listers, I am going to install a ldg light on my 701. The most obvious attachment location is the bracket connecting the landing gear bow. However, there are some lights available that might fit in the forward slat. Xevision has one measuring about 4"Wx4L"x2"H. Has anyone installed a light in their slats? Thanks in advance, Ken Arnold Building CH701 QB Kit; target completion May 2007 > [b] -------- Tommy Walker Read this topic online here: http://forums.matronics.com/viewtopic.php?p'978#96978 ________________________________ Message 25 ____________________________________ Time: 08:26:19 PM PST US From: "Bill Naumuk" Subject: Re: Zenith-List: 1st Hundred Hours of Building (XL) Rich- Sooner or later you're going to slip up and blow your timeline to hell. Homebuilder's fact of life. Take the advice of two Bills- kick back and relax. You WILL screw up. There isn't a builder on this list who hasn't! Forewarned is forearmed. do not archive Bill Naumuk HDS Fuselage Townville, Pa ----- Original Message ----- From: JAPhillipsGA@aol.com To: zenith-list@matronics.com Sent: Friday, February 23, 2007 7:36 PM Subject: Re: Zenith-List: 1st Hundred Hours of Building (XL) Rich, remember it's not a race. You're okay to enjoy it more. Drink a few more adult beverages along the way, tell your wife how difficult the work is, etc. We have all convinced our spouses it may take years and years and thousands and thousands of dollars to get to where your at. Please keep this a secret or they will have us painting the porch ceiling, changing the oil in their car and mowing the lawn. Yeach ! Best regards, Bill of Georgia ************************************** AOL now offers free email to everyone. Find out more about what's free from AOL at http://www.aol.com. ________________________________ Message 26 ____________________________________ Time: 10:28:06 PM PST US Subject: Zenith-List: Re: Engines From: "N601RT" Robert, Don't make your choice based on opinions from people that may not have real facts. Be careful to understand what are facts and what is rumor, possibly fear of the unknown. We all make significant investments (time and/or money) in our engines and therefore tend to think we have made the best choice. I think this can color our opinions. I agree the reason there are "lots of ADs" on Rotax 9xx engines is because there are LOTs of Rotax engines in service. I was told that there are more than 20,000 9xx engines in service a year ago. I just read that Rotax is currently producing 5,000 9xx family engines per year. (Both figures from Eric Tucker who teaches a GREAT Rotax maintenance class and who is THE technical guru for Kodiak [North America Rotax distributor]. Lockwood is an example of a dealer who gets their engines from Kodiak.) All engines have their pluses and minuses. My perspective on Rotax +/- Minuses: Expensive (compared to Corvair and Subaru conversion, I believe similar price to Jabaru) Parts are relative expensive 18a alternator (which I think this is relatively low output) Positive: Reliable Light overall installed weight for the horsepower Quiet Water cooled heads. (Different than water cooled engine, simpler) Mine basically does not use oil. I assume this is typical Nicasil plated cylinders, close tolerance pistons Shock cooling is not a concern Broad dealer network. (But your local A&P may not be familiar with it.) Large corporation stands behind and supports the engine LOTs of engines in service. Many examples of these have gone to TBO more than once. Optional 2nd alternator available. (Corvair and Subaru conversions have option for a variety of alternators. Jabaru has relatively low output alternator as does 9xx series.) Service and installation manuals available on line for download. Service Bulletins (ADs) available on line. These ARE NOT required for engines that are not certified. Recommend that you carefully understand what and why they are published. My local EAA chapter has done some noise testing. Richard VanGrunsven, his brothers and lots of other RV owner's are in the chapter. My plane was the quietest tested during climb out at the end of the runway and tied for quietest with the factory RV-10 for 1000 foot over flight at 90kts. The tests also include production planes. Paul's post to this thread has some misleading statements. There is no need to guess the history of the Rotax 912, 914 engine series. The Rotax 912, 914 series of engines are clean sheet, modern design aircraft engines. Yes Bombardier (parent company Rotax) makes snowmobile engines, but the 9xx series IS NOT related to the snowmobile engines. Before Bombardier created the separate Recreational Products division, the company who owned Rotax also owned Learjet. Maybe the 9xx was derived from a Learjet. [Wink] Propeller tips that are supersonic lose efficiency. They can be destroyed, but there are many propellers that go supersonic regularly. Not saying this is recommended, just not a certain disaster. Regards, Roy N601RT: CH601HDS, nose gear, Rotax 912ULS, All electric, IFR equipped, 681hrs, 802 landings Read this topic online here: http://forums.matronics.com/viewtopic.php?p=97013#97013 ________________________________ Message 27 ____________________________________ Time: 11:33:10 PM PST US From: "Ian McClelland" Subject: Zenith-List: Zenair News Do any list members subscribe to the Zenair Newsletters? If so any comments as to the quality/usefulness of the publication? On the face of it to me it appears to be necessary to ensure you have the latest recommendations and safety information from Zenith. I have some reservations about having to pay money for safety related and technical information that should be readily available to anyone who has purchased a set of plans or a kit. An E-mail service would be a low cost option. Are there any opinions out there? Ian McClelland New Zealand Plans builder of 601XL. Tail and flight controls done. 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