---------------------------------------------------------- Kolb-List Digest Archive --- Total Messages Posted Tue 01/03/06: 19 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:44 AM - Re: 2 Stroke VS 4 Stroke / Clutch Question (lucien stavenhagen) 2. 02:39 PM - Re: 2 Stroke vs 4 Stroke (Dennis Souder) 3. 03:04 PM - Re: 2 Stroke vs 4 Stroke (Don Gherardini) 4. 03:45 PM - Re: Tie downs, gust locks (David Lehman) 5. 04:34 PM - 2 Stroke vs 4 Stroke (frank & margie) 6. 04:42 PM - Re: 2 Stroke vs 4 Stroke (Beauford) 7. 05:10 PM - Re: 2 Stroke VS 4 Stroke (Dennis Souder) 8. 05:19 PM - Re: 2 Stroke vs 4 Stroke (ray anderson) 9. 06:19 PM - Re: 2 Stroke vs 4 Stroke (Don Gherardini) 10. 07:15 PM - Re: 2 Stroke vs 4 Stroke (Eugene Zimmerman) 11. 07:17 PM - Re: 2 Stroke vs 4 Stroke (Don Gherardini) 12. 07:18 PM - Re: 2 Stroke vs 4 Stroke (Don Gherardini) 13. 07:23 PM - Re: 2 Stroke VS 4 Stroke (Don Gherardini) 14. 07:53 PM - 2 and 4 Stroke (John Hauck) 15. 08:51 PM - Re: 2 Stroke VS 4 Stroke (Jim Baker) 16. 08:55 PM - Re: 2 and 4 Stroke (Jim Baker) 17. 09:10 PM - Two stroke cars..... (Jim Baker) 18. 09:14 PM - Re: 2 and 4 Stroke (John Hauck) 19. 10:56 PM - Re: 2 and 4 Stroke (Steve Garvelink) ________________________________ Message 1 _____________________________________ Time: 05:44:51 AM PST US From: "lucien stavenhagen" Subject: Re: Kolb-List: 2 Stroke VS 4 Stroke / Clutch Question --> Kolb-List message posted by: "lucien stavenhagen" >Lucien, > >How much experience do you have with the clutch? I was considering >putting one on my plane. How long do they last? Have you ever had any >slippage? Is it worth the money? ~ Earl This one is my first, but the previous owner of my FSII used one on the original motor for about 400 hours. They appear to last forever. According to the logbook, there was something like 2 thousandths of wear on the shoes after 200 hours of use... And there's something like 1/4" of lining on there. I still have the old one which I kept because I plan to use it on another project eventually. Never had any slippage at all, once engaged it's engaged and you don't even know it's there.... The RK-400 clutch is a very hefty, well built piece of equipment, very precision that gives no problems once installed (I don't work for AirTech, BTW, just a happy customer). Personally, I don't know how I ever got along without it now that I have it. Advantages: - Very easy starting. Heaven heaven heaven... Just like pull-starting a snomobile or ski-doo... - Eliminates the "rotax rattle" at idle, basically eliminating the stress that puts on the crank. The crank in the original motor went almost 500 hours with the clutch, I still have it and the runout is still within used limits (it's rotting away now but isn't worn out). - allows idling at 1500 rpm or even lower. - no brakes needed to hold position on the ground anymore. - allows practicing deadsticks without shutting motor down. Just pull back to idle and you're in the engine-out configuration! - windmilling prop adds a LOT of drag, which can be very useful in adjusting an approach. - stationary prop while on flight line quite a novelty, turns the heads of the other pilots, your friends and impresses girls. Disadvantages: - expensive, about $500 (well worth the money though IMO). - adds weight, about 3 lbs over the standard coupler it replaces in the C box. - can no longer hand prop engine in case starter is kaput. - To prevent excessive wear, you have to run it either engaged or disengaged. Fully engaged rpm is about 2800 or more which can be more than needed to taxi comfortably. So to taxi, you have to work the throttle back and forth, which can be slightly annoying (I've gotten used to this though). - noticeable rattle at idle when disengaged, if you care about such things (I don't and am used to it). This is due to the shoes rattling in the housing (personally, it reminds me that it's a stout, strong piece of equip). - windmilling prop adds a LOT of drag, which will significantly reduce your engine-off glide ratio. The only other thing about adding the clutch is getting the idle speed low enough to keep the clutch fully disengaged. The stock slides in the Bings, even when bottomed out completely, will still give an idle of 2100 or more. What I do is just idle a bit rich which solves the problem - when hot, the motor idles down nicely to 1500 to 1700...... Personally, I'll never not use the clutch again if I can help it... Best thing since sliced bread for me.... LS N646F ________________________________ Message 2 _____________________________________ Time: 02:39:20 PM PST US From: "Dennis Souder" Subject: Re: Kolb-List: 2 Stroke vs 4 Stroke --> Kolb-List message posted by: "Dennis Souder" Don, Are you trying to torment me? If so you are succeeding. Dennis > > Just think...if Dennis and Homer would have set out to design that firefly > to fit the v-twin industrials we have today instead of the 447...hmmmmmmmmm > > Don Gherardini > FireFly 098 > http://www.geocities.com/dagger369th/my_firefly.htm > > ________________________________ Message 3 _____________________________________ Time: 03:04:05 PM PST US From: "Don Gherardini" Subject: Re: Kolb-List: 2 Stroke vs 4 Stroke --> Kolb-List message posted by: "Don Gherardini" Herb, have not used the red ivo yet.....got distracted with a 47 Luscombe 8A which is now the project in the shed that will keep me outta the poolhalls this winter! I have always though that a Pup with about a 35 hp engine with a reduction drive, so as to get the prop speed down to 23 or 2400 and allow a bigger prop would be much better that the direct drive half v-dubs...but it is just a seat of the pants guess...no expierience personally. There are 2 N-3s at Tommy's airpark where I used to hangar..always admired em....but they took such a long takeoff roll.... 31 or 3200 is just too fast to spin a prop it seems to me...causes you to have to use such a small dia that it just doesnt seem to have a chance to maximize the 35 hp. That always seemed to be the biggest drawback of the v-dub. I bet that the new briggs 35 with a reduction like they are useing on airboats...swinging a 66 or 68 inch prop would get thet pup off the ground likety-split and climb like a Kol.....er...eh....well...climb alot better!! Then again...I dont know if a landing gear is long enough to allow that prop. what size is on the global? I feel for you pard on the 447....hope you dont have to send it off the the Count either... Don G ________________________________ Message 4 _____________________________________ Time: 03:45:26 PM PST US From: David Lehman Subject: Re: Kolb-List: Tie downs, gust locks --> Kolb-List message posted by: David Lehman I bought these when I had my Cessna 185, the kit is a little heavy, but it has great holding power and is easy to use... http://www.aircraftspruce.com/catalog/pspages/flyties.php David ________________________________ Message 5 _____________________________________ Time: 04:34:23 PM PST US From: "frank & margie" Subject: Kolb-List: 2 Stroke vs 4 Stroke --> Kolb-List message posted by: "frank & margie" "Briggs Vanguards are now up to 35 hp and are very well built engines and I bet a buck we will see alot of those on airplanes like the legal eagle's,N-3's and similar planes with alot of wing. Talk about range!..todays V-twin engines burn from 1.5 to 2 gallons an hour at WOT and full load. We need continuous duty designed engines for our sport...and the industrial engine market is quickly approaching a place where they will have just what the back to basic flying machines need...the difference this time around...is the engines will last about 20 time longer than the ones we started with back in the late 70s. BTW....a 24 hp honda costs about 1100 complete with electric starter. The 31 hp Vanguard is about 1500..and the 35 will probably be a 100 or so more...RETAIL....! Just think...if Dennis and Homer would have set out to design that firefly to fit the v-twin industrials we have today instead of the 447...hmmmmmmmmm" ---------------------------------------------------- Don/All, Appreciate the responses, they're what I consider really interesting reading. On an extremely timely subject, considering the current price of Rotaxes, and the effect Sport Pilot will likely have on U/L's. Don, I love the way you bring up at least as many new questions as ones you answer----and if you'll let me, I'd like to keep you (and Charlie/Herb/Jack/Michael) talking further. For instance, is a Vanguard rated for continuous duty now? If not, can it be derated (run at less RPM?) to continuous? What does one weigh? Would a 35HP put out 30 or so if rated continuous? (30 seems like a minimum needed----most of us don't want to go back to 25 or less---) I get the impression you think the Vanguard would work now, even if not rated for continuous. I'm also under the impression the BMW weighs too much for legal U/L's (but I hope I'm wrong---). Are there other near-continuous duty candidates out there now? What would Homer & Dennis have had to change to run a Vanguard on a 'Fly? Just more wing? OK, I'll quit----:) This List is the only intelligent U/L oriented forum I'm aware of (since the demise of the Phantom-Flightstar newsletter), and I for one, really enjoy it. Frank Clyma do not archive ________________________________ Message 6 _____________________________________ Time: 04:42:38 PM PST US From: "Beauford" Subject: Re: Kolb-List: 2 Stroke vs 4 Stroke --> Kolb-List message posted by: "Beauford" What's wrong with the 447...? I kinda like 'em..... Beauford do not archive ----- Original Message ----- From: "Dennis Souder" Subject: Re: Kolb-List: 2 Stroke vs 4 Stroke > --> Kolb-List message posted by: "Dennis Souder" > > Don, > > Are you trying to torment me? If so you are succeeding. > > Dennis > > > > > > Just think...if Dennis and Homer would have set out to design that firefly > > to fit the v-twin industrials we have today instead of the > 447...hmmmmmmmmm > > > > Don Gherardini > > FireFly 098 > > http://www.geocities.com/dagger369th/my_firefly.htm > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > ________________________________ Message 7 _____________________________________ Time: 05:10:25 PM PST US From: "Dennis Souder" Subject: Re: Kolb-List: 2 Stroke VS 4 Stroke --> Kolb-List message posted by: "Dennis Souder" Don, Are you familiar with the older Saabs that had 2-stroke engines: they had a 750 CC and an 850 CC, 3-cylinder. The Saab Sonnet had a 2-stroke too. I had one of each and ran them both for a long time. They were very conservatively rated. (They had a light that came on when it was time to add another quart of oil to the oil injector tank.) Dennis > A 2 cycle can easily be built as reliable as a 4 cycle...but it is almost > impossible to build one as "durable"...I say "almost" because someone who > works for Detroit Deisel might be reading here and take issue with the > statement. ________________________________ Message 8 _____________________________________ Time: 05:19:00 PM PST US From: ray anderson Subject: Re: Kolb-List: 2 Stroke vs 4 Stroke --> Kolb-List message posted by: ray anderson Someone might want to investigate the Onan Industrial 2 cylinder models ( 4 cycle). I ran one on my Quickie with very satisfactory results. There is a slight modification needed to reduce the weight but easily done. When Bert Rutan designed the Quickie for his brother in law and his partner, they decided the Onan was the best bet considering weight, etc. As you probably know, the Onan has been a favorite for many years in fields like continuous operation pumping oil in the field without a lot of supervision. Never tell anyone connected with them, including the local distributors, you intend to use it on an airplane. That makes them run for cover fast. UltraStar ..Tenn Do not archive frank & margie wrote: --> Kolb-List message posted by: "frank & margie" "Briggs Vanguards are now up to 35 hp and are very well built engines and I bet a buck we will see alot of those on airplanes like the legal eagle's,N-3's and similar planes with alot of wing. Talk about range!..todays V-twin engines burn from 1.5 to 2 gallons an hour at WOT and full load. We need continuous duty designed engines for our sport...and the industrial engine market is quickly approaching a place where they will have just what the back to basic flying machines need...the difference this time around...is the engines will last about 20 time longer than the ones we started with back in the late 70s. BTW....a 24 hp honda costs about 1100 complete with electric starter. The 31 hp Vanguard is about 1500..and the 35 will probably be a 100 or so more...RETAIL....! Just think...if Dennis and Homer would have set out to design that firefly to fit the v-twin industrials we have today instead of the 447...hmmmmmmmmm" ---------------------------------------------------- Don/All, Appreciate the responses, they're what I consider really interesting reading. On an extremely timely subject, considering the current price of Rotaxes, and the effect Sport Pilot will likely have on U/L's. Don, I love the way you bring up at least as many new questions as ones you answer----and if you'll let me, I'd like to keep you (and Charlie/Herb/Jack/Michael) talking further. For instance, is a Vanguard rated for continuous duty now? If not, can it be derated (run at less RPM?) to continuous? What does one weigh? Would a 35HP put out 30 or so if rated continuous? (30 seems like a minimum needed----most of us don't want to go back to 25 or less---) I get the impression you think the Vanguard would work now, even if not rated for continuous. I'm also under the impression the BMW weighs too much for legal U/L's (but I hope I'm wrong---). Are there other near-continuous duty candidates out there now? What would Homer & Dennis have had to change to run a Vangu! ard on a 'Fly? Just more wing? OK, I'll quit----:) This List is the only intelligent U/L oriented forum I'm aware of (since the demise of the Phantom-Flightstar newsletter), and I for one, really enjoy it. Frank Clyma do not archive --------------------------------- ________________________________ Message 9 _____________________________________ Time: 06:19:36 PM PST US From: "Don Gherardini" Subject: Re: Kolb-List: 2 Stroke vs 4 Stroke --> Kolb-List message posted by: "Don Gherardini" Dennis, So very sorry pard...definately no intention to torment! The honest truth is...I believe the FireFly very likely to be the best purpose designed little airplane in the part 103 market. I Dont know all the exact details of what went on back when this baby was spawned, I have heard bits and pieces, and I dont know how much you had to do with it, but since your name is on every single page of the prints I have, I suspect you put an awful lot of yourself into that project. Sometimes I dont think people appreciate just what this plane really is...and the resale value of them seems to support that thought, not that I want to sell mine. What other legal ultralite flys with the responsiveness of a FireFly? What other legal ultralite performs as well as the FireFly? Rate of Climb?....Top Speed?....roll response?... What other legal ultralite builds as easy as the FireFly? I could go on...But anyone who has flown one and has any experience in very many of the other 103 legal birds out there will line up right behind me I bet. NO Dennis...if that little comment I made about a conversation between you and Homer would have really happened, We would have had a different plane, and I am quite certain it would not have been near the fun to fly bird as a FireFly is today. Now, you may know the truth, but I dont believe there was much luck involved here, just an honest evolution of a design into an airplane that is perfectly matched to the engine choice. I must be honest and say that I had been aware for along time of The Kolbs, but never really believed they were all that much different than the rest. When I stumbled onto this FireFly, built it and flew it, it was probably within the first hour of flight time that I was saying to myself.."I cant believe I didnt get one a these a long time ago" IN fact, now that I have a Luscombe project going on in the pole-shed, my wife keeps asking, "what are we gonna do with 2 airplanes?", and "are you going to sell the FireFly?" and so on...WEll, because you had the forethought to put folding wings on it, it will fit in the rented hanger with the Luscombe...or about any other plane I will ever be able to afford to park in there. I suspect it will be a very long time before I find another plane that will satisfy the urges as economically, and as completely as the Fly. NO Sir Mr. Souder, No torment intended. Job very well done. What you might consider however, is figureing out a NEW and Different design that would take advantage of the upcoming generation of V-twin industrials. The mere fact that the engines would cost so much less, be so much more durable, More competitive(read that as several choices of brand) and less "finicky" than 2 strokes ,would almost insure a market success, and YOU would likely be given credit for turning the entire part 103 market into a new and more affordable direction. That direction would be alot closer to the path we all started out on so many years ago before law dogs and Rotax engine domination got the reigns and steered us to where we are today. I might think that the resulting airplane would never perform as well as a 447 Firefly, given a slightly heavier engine of slightly less horsepower...but then...It wouldnt have to. It would be a different plane...and with an engine that cost 3000 dollars less...the whole plane would be a third less cost to the owner...give or take....hmmmmmm dang....now it sounds like I am tormenting you huh......sorry...... Thanks Dennis for your part in bringing us the FireFly, a masterpiece that has yet to be outdone! Don Gherardini FireFly 098 http://www.geocities.com/dagger369th/my_firefly.htm P.S. Should you ever decide to try such a thing, I will GIVE you an engine...or 2 or 3 to help it along. ________________________________ Message 10 ____________________________________ Time: 07:15:10 PM PST US From: Eugene Zimmerman Subject: Re: Kolb-List: 2 Stroke vs 4 Stroke --> Kolb-List message posted by: Eugene Zimmerman Don, what we really need is not another plane but a good reliable prop GEAR reduction for the 35 horse Vanguard. Who would want to go back to a belt again? Something like a C box with a clutch might work ok with the right ratio. On Jan 3, 2006, at 9:23 PM, Don Gherardini wrote: > --> Kolb-List message posted by: "Don Gherardini" eleven.net> > > > P.S. Should you ever decide to try such a thing, I will GIVE you an > engine...or 2 or 3 to help it along. > > ________________________________ Message 11 ____________________________________ Time: 07:17:00 PM PST US From: "Don Gherardini" Subject: Re: Kolb-List: 2 Stroke vs 4 Stroke --> Kolb-List message posted by: "Don Gherardini" Frank, All of the current industrial v-twins are what the market considers continuous duty engines, however their continuous duty rating is slightly less that advertised hp...generally in the 90% range. Without looking at the Vanguard website..I would guess it the 35 is rated at about 32 continuous...but in our industry, it is generally accepted as a 1 hour rating...in other words...35 hp for 1 hour max...and 32 hp cont. All the companies except Kohler have adopted a design goal of 2500 hours at the cont rating. (Kohlers are much less) The biggest thing one can consider, is the torque rating. Already any current crop industrial 25 to 28 hp or so v-twin has a torque rating of a Rotax 503. And it is the torque that we want to turn a prop. I suggest to you all that a 35 hp industrial will probably out perform a 50 hp 2 cycle when the job is turning a prop. Also, due to the industrial markets demands for torque...they all produce peak torque at around 24 to 2600 and the curve stays the same thru around 3200...then it drops off a bit...but not much. Now as to what would need to be changed on a Firefly to run a vanguard...I cannot say for sure, for I am certainly not an aircraft designer...I will defer to someone with more experience and knowledge on that one. I will speculate that nothing needs to be changed to be able to make it fly with one...but as I inferred in a prev post..it is designed to be maximized with a 447, and likely nothing will be better than that on one. Don Gherardini FireFly 098 http://www.geocities.com/dagger369th/my_firefly.htm ________________________________ Message 12 ____________________________________ Time: 07:18:49 PM PST US From: "Don Gherardini" Subject: Re: Kolb-List: 2 Stroke vs 4 Stroke --> Kolb-List message posted by: "Don Gherardini" Beauford, I cant think of anything wrong with a 447 either..I like mine alot too. If I had to wish for something...I would wish they would last longer and burn less fuel and cost about a third of what they do...but just cause they dont do any of the above dont make em bad.. Don ________________________________ Message 13 ____________________________________ Time: 07:23:46 PM PST US From: "Don Gherardini" Subject: Re: Kolb-List: 2 Stroke VS 4 Stroke --> Kolb-List message posted by: "Don Gherardini" Dennis, YEs..I am Vaguely familiar with those old saabs....I also remember the old Opel wagon with a 2 cycle engine...a buddy of mine had one in high school, it was a really neat engine, but there wasnt a thing it would do that my 65 289 mustang wouldnt do alot better! I will tell you that before I worked for Honda...I was with a certain Swedish equipment company for 12 years, To this very day, I think no,one builds 2 cycles better than the swedes! Don ________________________________ Message 14 ____________________________________ Time: 07:53:56 PM PST US From: "John Hauck" Subject: Kolb-List: 2 and 4 Stroke --> Kolb-List message posted by: "John Hauck" Hi Gang: Been a lot of discussion about 2 and 4 stroke engines for our little airplanes. I had the opportunity to build and fly three 2 stroke powered Kolbs, and am still flying the third one, but not with 2 stroke any more. Did some serious cross country flying with a 447 point ign engine and an original Firestar. Had a ball doing them all. Had some disappointments, but survived them. Like an engine failure over the Niagara River, just north of Buffalo, NY. Broke the airplane in the process of getting me back on the ground. Got it repaired in about 4 days and flew a very bent FS back to Alabama. That engine out and bent airplane was the decision point to rebuild the FS to do serious cross country flying a little better than the first time around. BTW the engine failure was caused by the NGK fine wire plugs I was using. One of them let go of the tiny center electrode which lodged between the ground strap and the base of the spark plug, effectively shutting it down. Won't fly on one cylinder. Don't ask me how I got off on that tangent, but what I wanted to share was a very short description of what I see as the major difference between the 2 and 4 stroke light aircraft engines. Primarily, lubrication. The 4 stroke uses a dedicated, precision type, pressure lube system. The 2 stroke uses a fuel/oil/air mix that relies on air flow and chance to get things lubricated correctly. As far as reliability is concerned, the area the 4 stroke is hands down over the 2 stroke is piston to cylinder wall lubrication. Here the 2 stroke does a good job as long as that microscopic film of oil is kept in place between the piston and cylinder wall metal. If, at anytime, it is broken, just a little bit, the piston is going to scuff and probably seize in the cylinder. We don't have that problem with the 4 stroke unless we loose oil pressure, and then the crank and rod bearings are going to go first. There are a lot of ways to break the oil film in a 2 stroke: 1-broken ring 2-stuck ring and a little blow by 3-produces a lot of carbon that might have a bearing on creating a break in the oil film 4-acts of God 5-unnatural, mysterious, unexplainable acts Can't think of any more at this time, but maybe you all can. Correct me if I am wrong, but I don't know of any problems we have suffered with the 4 stroke Rotax in the area of piston and cylinder scuffing and seizing. In fact, the factory tolerance for piston to cylinder wall clearance when new is 0.000 to 0.001". Not a whole lot of clearance. However, another advantage of the 912 is the use of plated aluminum cylinders and not cast iron or steel sleeves as used in the 2 strokes. Not looking for arguments. Thinking out loud tonight and wanted to share my thoughts. Most engine failures are operator induced on both 2 and 4 stroke engines. I believe the critical difference is the all important oil film on the cylinder wall. john h mkIII hauck's holler, alabama ________________________________ Message 15 ____________________________________ Time: 08:51:28 PM PST US From: "Jim Baker" Subject: Re: Kolb-List: 2 Stroke VS 4 Stroke --> Kolb-List message posted by: "Jim Baker" > Are you familiar with the older Saabs that had 2-stroke engines: they > had a 750 CC and an 850 CC, 3-cylinder. The Saab Sonnet had a > 2-stroke too. I had one of each and ran them both for a long time. > They were very conservatively rated. (They had a light that came on > when it was time to add another quart of oil to the oil injector > tank.) Had four different two stroke cars in Japan in the mid 70's. Two were air cooled two cylinder 500cc and two were 750cc three cylinder, four speed, water cooled. All of them were Suzuki. Used one of the 750s for gymkhana, a slalom type event. We beat the living crud out of that car, well past redline, ported, stuffed crankcase, honkin big expansion chambers (that's one of the ways I lost some high frequency hearing). Sure wish I had a couple of them now...... Jim Baker 580.788.2779 '71 SV, 492TC Elmore City, OK ________________________________ Message 16 ____________________________________ Time: 08:55:41 PM PST US From: "Jim Baker" Subject: Re: Kolb-List: 2 and 4 Stroke --> Kolb-List message posted by: "Jim Baker" >However, another advantage of the 912 is the use of > plated aluminum cylinders and not cast iron or steel sleeves as used > in the 2 strokes. Aaaakkkk! Heresy! My Hirth has the same Nikasil as your 912. So there! ; ) Jim Baker 580.788.2779 '71 SV, 492TC Elmore City, OK ________________________________ Message 17 ____________________________________ Time: 09:10:16 PM PST US From: "Jim Baker" Subject: Kolb-List: Two stroke cars..... --> Kolb-List message posted by: "Jim Baker" Whoops...old age. The Suzuki displacements were 360cc and then 500cc. Time has a way of inflating memories.... Jim Baker 580.788.2779 '71 SV, 492TC Elmore City, OK ________________________________ Message 18 ____________________________________ Time: 09:14:04 PM PST US From: "John Hauck" Subject: Re: Kolb-List: 2 and 4 Stroke --> Kolb-List message posted by: "John Hauck" | there! | | ; ) | | | Jim Baker Sorry Jim: Was talking about Rotax (or is it Rotaxen?) Should have spelled that out in my original post. Rotax calls it something else, and my Suzuki DRZ400E 4 stroke thumper calls it something else again, and Yamaha thumpers call their plating something difference. Amazing technology. There is a plant in Auburn, Alabama, that will replate a single cylinder for about $150.00. When they finish with it, it is ready to go back together. Send the new piston along with the cylinder so they can hone it to specs. Will be a new cylinder no matter how bad you screw it up. I imagine your Hirth still survives as long as that microscopic film of oil is in place between piston and cylinder. john h Titus, Alabama ________________________________ Message 19 ____________________________________ Time: 10:56:38 PM PST US From: "Steve Garvelink" Subject: RE: Kolb-List: 2 and 4 Stroke --> Kolb-List message posted by: "Steve Garvelink" Gentlemen, This has been the most interesting post session of the year. I guess I have been very interested in this very subject. I have a pressure washing business and use these little industrial engines and from what I have seen would have no problem putting one behind me as a power plant. I have used the briggs 18hp L-head engines at close to maximum power and regularly get 3000 plus hours of service out of them. I have not used the v-twins yet but plan on replacing both of my engines with them soon. The question that I have is if you can get the engine to run slow enough to run the prop with out a reduction drive. I truly believe that These engines will bring about a new chapter in ultralight aircraft. I Thank Don and all who have contributed to this post . Steve Garvelink -----Original Message----- From: owner-kolb-list-server@matronics.com [mailto:owner-kolb-list-server@matronics.com] On Behalf Of John Hauck Subject: Re: Kolb-List: 2 and 4 Stroke --> Kolb-List message posted by: "John Hauck" | there! | | ; ) | | | Jim Baker Sorry Jim: Was talking about Rotax (or is it Rotaxen?) Should have spelled that out in my original post. Rotax calls it something else, and my Suzuki DRZ400E 4 stroke thumper calls it something else again, and Yamaha thumpers call their plating something difference. Amazing technology. There is a plant in Auburn, Alabama, that will replate a single cylinder for about $150.00. When they finish with it, it is ready to go back together. Send the new piston along with the cylinder so they can hone it to specs. Will be a new cylinder no matter how bad you screw it up. I imagine your Hirth still survives as long as that microscopic film of oil is in place between piston and cylinder. john h Titus, Alabama