From: krnet-bounces@mylist.net To: John Bouyea Subject: KRnet Digest, Vol 346, Issue 19 Date: 4/10/2004 6:21:07 PM Send KRnet mailing list submissions to krnet@mylist.net To subscribe or unsubscribe via the World Wide Web, visit http://mylist.net/listinfo/krnet or, via email, send a message with subject or body 'help' to krnet-request@mylist.net You can reach the person managing the list at krnet-owner@mylist.net When replying, please edit your Subject line so it is more specific than "Re: Contents of KRnet digest..." Today's Topics: 1. Re: Elevator Mass Balance mounting (Phillip Matheson) 2. Re: Elevator Mass Balance mounting (joe) 3. Jabiru Engine+Diehl Gear (Garrie Burnell) 4. RE: Elevator Mass Balance mounting (Murray Gill) 5. Re: Jabiru Engine+Diehl Gear (Gavin Donohoe) 6. O200 (Gavin Donohoe) 7. Rod end Hinges - the true story (Stephen Jacobs) 8. Elevator Mass Balance mounting (Stephen Jacobs) 9. Re: Elevator Mass Balance mounting (joe) 10. RE: Tri-gear retrofits (Scott Bailey) 11. RE: Stephen Jacobs (Stephen Jacobs) 12. RE: Stick linkages (Doug Rupert) 13. Weigh in update. (Mark Jones) 14. Re: Elevator Mass Balance mounting (Edward Seaman) 15. Supercharging vs Turbocharging (Colin & Bev Rainey) 16. RE: Diehl Gear (Jack Cooper) 17. Re: Elevator Mass Balance mounting (joe) 18. Re: Elevator Mass Balance mounting (joe) 19. Re: Elevator Mass Balance mounting (joe) 20. RE: Supercharging vs Turbocharging (Doug Rupert) ---------------------------------------------------------------------- Message: 1 Date: Sat, 10 Apr 2004 16:20:02 +1000 From: "Phillip Matheson" Subject: Re: KR> Elevator Mass Balance mounting To: "KRnet" Message-ID: <003301c41ec3$dc222de0$6f96dccb@StationW2k04> Content-Type: text/plain; charset="iso-8859-1" Jim Wrote Was the strengh of the counterbalance mount the original issue, or am I having a senior moment? ------------ Yes , my point in the begining ( before all this got carried away) was to impact on the importance of the Mass mounting arm strength as well as the way it is mounted to the elevator I was concerned with the mass weight on the elevator tips. and glassing 4130 to the tips and filling with lead. Where Mark Lankford has mounted his on the Bell crank infront of the elevator. I also know the John Martindale from here ,( Down Under) mounted his mass weight on the bell crank mounted to the rear spar. But at least it got some comments. Has anyone got any comments on my post regarding R.E.Bearings on the rudder, and the side load weight of the rudder on the Rod end Bearing???? How will the REB handle the side Load??? Phillip Matheson matheson@dodo.com.au Australia VH PKR See our engines and kits at. http://www.vw-engines.com/ http://www.homebuilt-aviation.com/ See my KR at Mark Jones web http://mywebpage.netscape.com/n886mj/pmkr2.html ------------------------------ Message: 2 Date: Sat, 10 Apr 2004 00:57:24 -0700 From: "joe" Subject: Re: KR> Elevator Mass Balance mounting To: "KRnet" Message-ID: <004401c41ed1$75f4eb80$0a0110ac@o7p4e3> Content-Type: text/plain; charset="iso-8859-1" Weight on the ends distributes more effectively when dynamic forces are applied. I have used this method on the last aircraft I built(not a KR). Please don't use this as a solution on my account without more expert advice. Joe ----- Original Message ----- From: "Phillip Matheson" To: "KRnet" Sent: Friday, April 09, 2004 11:20 PM Subject: Re: KR> Elevator Mass Balance mounting > Jim Wrote > Was the strengh of the counterbalance mount the original issue, or > am I having a senior moment? > ------------ > > Yes , my point in the begining ( before all this got carried away) > was to > impact on the importance of the Mass mounting arm strength as well as > the way it is mounted to the elevator > > I was concerned with the mass weight on the elevator tips. and > glassing 4130 to the tips and filling with lead. > > Where Mark Lankford has mounted his on the Bell crank infront of the > elevator. > I also know the John Martindale from here ,( Down Under) mounted his mass > weight on the bell crank mounted to the rear spar. > > But at least it got some comments. > > Has anyone got any comments on my post regarding R.E.Bearings on the > rudder, and the side load weight of the rudder on the Rod end Bearing???? > How will the REB handle the side Load??? > > > > > Phillip Matheson > matheson@dodo.com.au > Australia > VH PKR > See our engines and kits at. > http://www.vw-engines.com/ > http://www.homebuilt-aviation.com/ > See my KR at Mark Jones web > http://mywebpage.netscape.com/n886mj/pmkr2.html > > > > > > > > > _______________________________________ > to UNsubscribe from KRnet, send a message to KRnet-leave@mylist.net > please see other KRnet info at http://www.krnet.org/info.html ------------------------------ Message: 3 Date: Sat, 10 Apr 2004 11:25:26 +0300 From: "Garrie Burnell" Subject: KR> Jabiru Engine+Diehl Gear To: krnet@mylist.net Message-ID: Content-Type: text/plain; format=flowed Has anyone installed an Australian made Jabiru 2200 engine in there KR-2. I have a KR-2 built by someone else with a 1835VW engine. It works fine but as it is a VW it is very noisy. The Jabiru engine's are very quiet, whisper quiet and very reliable and the factory is just up the road from me. So, I am going remove the VW and install the Jabiru and also remove the fixed taildragger gear to go with the Diehl tricycle gear, which is yet to be purchased. My next question is, does anyone have Diehl tri-gear for sale and how does it stand up to roughish grass/dirt strips? Thanks, Garrie. _________________________________________________________________ MSN 8 with e-mail virus protection service: 2 months FREE* http://join.msn.com/?page=features/virus ------------------------------ Message: 4 Date: Sat, 10 Apr 2004 18:34:56 +1000 From: "Murray Gill" Subject: RE: KR> Elevator Mass Balance mounting To: "KRnet" Message-ID: <000301c41ed6$b44d0e80$2202a8c0@ABT2400> Content-Type: text/plain; charset="iso-8859-1" Phil, Re your question about rod end bearings for attaching a rudder: I downloaded the Aurora catalogue http://www.aurorabearing.com/2003-04_Internet_Catalog.pdf and from a quick read it would appear that the load you are concerned about is the axial load when used as a rudder hinge. For a three piece rod end, such as the MW3 used in the Dean hinge solution, (see article on Mark Langford's site) the maximum axial load should be no greater than 10% of the radial load. For the MW3 the maximum radial load is 6,805 Newtons which is the force exerted by a load of 694 kg or 1527 lb. 10% of that is 153lb which would be the ultimate load. If you are designing for the utility category the limit load is calculated at 4.4g and if a composite structure the ultimate load is 2 x limit load ie 8.8g. I guess that means the weight of the rudder should be limited to about 153/8.8 = 17.38 lb. Of course this calculation assumes that the whole rudder load is being taken on one bearing. (It also assumes I know what I'm talking about) For what its worth :-) Murray Gill ------------------------------ Message: 5 Date: Sat, 10 Apr 2004 19:48:26 +1000 From: "Gavin Donohoe" Subject: Re: KR> Jabiru Engine+Diehl Gear To: "KRnet" Message-ID: <001801c41ee0$f9456a00$c44d8690@oemcomputer> Content-Type: text/plain; charset="iso-8859-1" HI Garrie, You must live close to me!! I'm in Gladstone QLD. If you go to the SAAA web site and then look in the classifieds you will see someone in Victoria has a KR2 in boat stage for sale, it has Diehl gear and a host of other things for sale that he won't separate, but it may be worth a call to him. Incidentally I'm looking for an engine too I was, and still may use the EJ22 Subaru engine, but I'm concerned with the weight !!! Maybe you know where I can get an O200 Continental they're a fair bit lighter and easier to install. Gav ----- Original Message ----- From: "Garrie Burnell" To: Sent: Saturday, April 10, 2004 6:25 PM Subject: KR> Jabiru Engine+Diehl Gear > Has anyone installed an Australian made Jabiru 2200 engine in there > KR-2. I > have a KR-2 built by someone else with a 1835VW engine. It works fine > but as > it is a VW it is very noisy. The Jabiru engine's are very quiet, > whisper quiet and very reliable and the factory is just up the road > from me. So, I am going remove the VW and install the Jabiru and also > remove the fixed taildragger gear to go with the Diehl tricycle gear, > which is yet to be purchased. My next question is, does anyone have > Diehl tri-gear for sale and > how does it stand up to roughish grass/dirt strips? > Thanks, Garrie. > > _________________________________________________________________ > MSN 8 with e-mail virus protection service: 2 months FREE* > http://join.msn.com/?page=features/virus > > > _______________________________________ > to UNsubscribe from KRnet, send a message to KRnet-leave@mylist.net > please see other KRnet info at http://www.krnet.org/info.html > --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.656 / Virus Database: 421 - Release Date: 09/04/2004 ------------------------------ Message: 6 Date: Sat, 10 Apr 2004 19:52:44 +1000 From: "Gavin Donohoe" Subject: KR> O200 To: "KR builders and pilots" Message-ID: <001c01c41ee1$92ae7c40$c44d8690@oemcomputer> Content-Type: text/plain; charset="Windows-1252" HI All, I'm shying away from the EJ22 now in favour of the Continental O200 for weight reasons. Trouble is over here in Australia it's hard to get one (O200). Are they hard to get in the US as well? If not who would be able to help me find one and organise shipping to Australia? Gavin Australia PS we don't get Corvairs here or I might have one of them instead --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.656 / Virus Database: 421 - Release Date: 09/04/2004 ------------------------------ Message: 7 Date: Sat, 10 Apr 2004 12:44:05 +0200 From: "Stephen Jacobs" Subject: KR> Rod end Hinges - the true story To: , "'KRnet'" Message-ID: <000b01c41ee8$c5e435d0$2064a8c0@homedesktop> Content-Type: text/plain; charset="us-ascii" >>>> I guess that means the weight of the rudder should be limited to >>>> about 153/8.8 = 17.38 lb. >>> Of course this calculation assumes that the whole rudder load is >>> being taken on one bearing. (It also assumes I know what I'm >>> talking about) And clearly you do - thank you Murray, I was also interested in the answer to this one. ------------------------------ Message: 8 Date: Sat, 10 Apr 2004 12:56:02 +0200 From: "Stephen Jacobs" Subject: KR> Elevator Mass Balance mounting To: "'KRnet'" Message-ID: <000c01c41eea$6dab7430$2064a8c0@homedesktop> Content-Type: text/plain; charset="us-ascii" Hi Guys Some of the stuff I have been reading here is really worrying - particularly after we had some input from Phil (Oz) - with particular reference to weight distribution and G loading requirements. This may be one good example of leaving well alone unless you know what you are talking about. It is interesting that the pilots that have experienced flutter become very preoccupied with wanting tell everyone that will listen. (at least those that lived to talk about it). Fortunately the irreplaceable Tony Bingelis did both (experience and survive flutter) I wish I could find the URL to the original articles by Mr. Bingelis who (in my opinion) does know what he is talking about. In the interim, this extract from one of two articles (by Tony) that I have on the topic. I do not remember any copyright restrictions - I tend to look for and respect such warnings. I would not be surprised if these (and more) are in the KRnet archives somewhere - failing which, I am happy to email both to anyone interested - let me have your address. MS Word format would mean you get to see his drawings as well (not many). I selected this particular section because of the recent flurry of discussion on G loading of counter-weights. Steve J How to Mass Balance Control Surfaces Sport Aviation- 08/79 By Tony Bingelis (Extract Only - Not the Complete Article) Distribution of Mass Balance Concentrating a single externally mounted mass balance weight in one location to balance the control surface may not be ideal but because of limited space available inside the structure, it is usually more convenient to do so. However, whenever possible, distribute the weight uniformly along the span of the control surface. If the weights must be separate and attached in two or more locations along the span, they should be positioned, if possible, on either side of hinges to reduce flexing and torsional stresses on the structure. A method for obtaining good distribution of balance is through the installation of a solid steel rod along the entire length of the leading edge or perhaps you could install a steel tube instead. Although the steel tube would be lighter than a steel rod, its weight could be increased to exceed that of the solid rod by pouring in molten lead to obtain whatever additional weight is needed. You may have to pre-heat the tube to achieve this objective. (Naturally, you will remember to plug the open end?) Not only must balance weights be attached solidly, they must also be capable of withstanding high G loads. How high's high? Well, in a yesteryear study conducted at the NASA Langley Research Center by Arthur A. Regier (Flutter of Control Surfaces and Tabs), it was determined that the balance weights should be capable of withstanding 36 G's normal to the surface. However, more recently (1979), the FAA, in its AC23.629-1 "Means of Compliance with FAR 23.629, Flutter," states that all balance weight supporting structure should be designed for a limit static load of 24 G's normal to a plane containing the hinge and the weight and 12 G's within that plane parallel with the hinge. FAA also points out that proof of these criteria can be accomplished by simple static tests of the control surface mounted in a jig. That's really not too much as a 2 lb. weight need only be static tested to 48 lbs. to equal the requirement imposed on store bought aircraft. Now that you have all this under control, take care that the weights will not work loose under prolonged use and vibration or all that G load capability will be for naught. A Summary On Balancing Controls Many aircraft currently flying do not have balanced ailerons or elevators or rudders. These designs, however, have proven to be inherently free from flutter problems for the most part. So, I can't say with any conviction that the designer intended for them to be balanced or that they need it. However, and of this you may be sure, regardless of whether your plans require mass balancing of one or more control surfaces, you will never be sure they are flutter-free until they have been tested in flight - for that tendency ------------------------------ Message: 9 Date: Sat, 10 Apr 2004 04:20:04 -0700 From: "joe" Subject: Re: KR> Elevator Mass Balance mounting To: "KRnet" Message-ID: <006e01c41eed$c61eb480$0a0110ac@o7p4e3> Content-Type: text/plain; charset="iso-8859-1" The actual tests and results for elevator balancing for the many kit aircraft on the market are available from the manufacturers, including the results of the (GVT) Ground Vibration Tests done to establish flutter. Also the established methods for Elevator Balancing with illustrations are easy to come by. Joe ----- Original Message ----- From: "Stephen Jacobs" To: "'KRnet'" Sent: Saturday, April 10, 2004 3:56 AM Subject: KR> Elevator Mass Balance mounting > Hi Guys > > Some of the stuff I have been reading here is really worrying - > particularly after we had some input from Phil (Oz) - with particular > reference to weight distribution and G loading requirements. > > This may be one good example of leaving well alone unless you know what > you are talking about. > > It is interesting that the pilots that have experienced flutter become > very preoccupied with wanting tell everyone that will listen. (at least > those that lived to talk about it). Fortunately the irreplaceable Tony > Bingelis did both (experience and survive flutter) > > I wish I could find the URL to the original articles by Mr. Bingelis who > (in my opinion) does know what he is talking about. In the interim, > this extract from one of two articles (by Tony) that I have on the > topic. I do not remember any copyright restrictions - I tend to look > for and respect such warnings. > > I would not be surprised if these (and more) are in the KRnet archives > somewhere - failing which, I am happy to email both to anyone interested > - let me have your address. MS Word format would mean you get to see > his drawings as well (not many). > > I selected this particular section because of the recent flurry of > discussion on G loading of counter-weights. > > Steve J > > > How to Mass Balance Control Surfaces > Sport Aviation- 08/79 > By Tony Bingelis > > > (Extract Only - Not the Complete Article) > > Distribution of Mass Balance > > Concentrating a single externally mounted mass balance weight in one > location to balance the control surface may not be ideal but because of > limited space available inside the structure, it is usually more > convenient to do so. However, whenever possible, distribute the weight > uniformly along the span of the control surface. If the weights must be > separate and attached in two or more locations along the span, they > should be positioned, if possible, on either side of hinges to reduce > flexing and torsional stresses on the structure. > > A method for obtaining good distribution of balance is through the > installation of a solid steel rod along the entire length of the leading > edge or perhaps you could install a steel tube instead. Although the > steel tube would be lighter than a steel rod, its weight could be > increased to exceed that of the solid rod by pouring in molten lead to > obtain whatever additional weight is needed. You may have to pre-heat > the tube to achieve this objective. (Naturally, you will remember to > plug the open end?) > Not only must balance weights be attached solidly, they must also be > capable of withstanding high G loads. How high's high? Well, in a > yesteryear study conducted at the NASA Langley Research Center by Arthur > A. Regier (Flutter of Control Surfaces and Tabs), it was determined that > the balance weights should be capable of withstanding 36 G's normal to > the surface. However, more recently (1979), the FAA, in its AC23.629-1 > "Means of Compliance with FAR 23.629, Flutter," states that all balance > weight supporting structure should be designed for a limit static load > of 24 G's normal to a plane containing the hinge and the weight and 12 > G's within that plane parallel with the hinge. FAA also points out that > proof of these criteria can be accomplished by simple static tests of > the control surface mounted in a jig. That's really not too much as a 2 > lb. weight need only be static tested to 48 lbs. to equal the > requirement imposed on store bought aircraft. > Now that you have all this under control, take care that the weights > will not work loose under prolonged use and vibration or all that G load > capability will be for naught. > > > A Summary On Balancing Controls > > Many aircraft currently flying do not have balanced ailerons or > elevators or rudders. These designs, however, have proven to be > inherently free from flutter problems for the most part. So, I can't say > with any conviction that the designer intended for them to be balanced > or that they need it. However, and of this you may be sure, regardless > of whether your plans require mass balancing of one or more control > surfaces, you will never be sure they are flutter-free until they have > been tested in flight - for that tendency > > > > _______________________________________ > to UNsubscribe from KRnet, send a message to KRnet-leave@mylist.net > please see other KRnet info at http://www.krnet.org/info.html ------------------------------ Message: 10 Date: Sat, 10 Apr 2004 06:09:30 -0700 From: "Scott Bailey" Subject: RE: KR> Tri-gear retrofits To: , "'KRnet'" Message-ID: <003001c41efd$159015e0$4bd6fea9@ibmvxz1afc2o0w> Content-Type: text/plain; charset="us-ascii" Brian, Actually the plane is upside down. The reason I asked the question and contemplated this approach was that I wasn't considering the need for stiffness of the skin in this area. Thank you for your thoughts. Scott Bailey Belmont, CA -----Original Message----- From: Brian Kraut [mailto:brian.kraut@engalt.com] Sent: Friday, April 09, 2004 2:56 PM To: KRnet Subject: Re: KR> Tri-gear retrofits As Mark said, you won't hve any stifness with just glass, unless you did a piece 1/8" thick which you could never fair correctly. I would glue in a piece of 2" foam and glass over it. I am assuming that the reason for trying to do it some other way is because the plane is not upside down. You should be able to glass the foam upside down if you put two layers of glass and epoxy on somethink like thin masonite with bagging film on it then stick it up to the foam surface you have already prepared. You will need something to hold up the masonite in place. Figure that out before you start the glass and epoxy! Something you can blow up to keep even pressure on it like a raft might work O.K. I did some upside down glassing on the tops of my wing while the plane was upside down. I was able to use bagging film stretched tight and held on with tape. ---------- Original Message ---------------------------------- From: "Mark Langford" Reply-To: KRnet Date: Fri, 9 Apr 2004 15:10:00 -0500 >Scott Bailey wrote: > >> My question is that since the underside of the wing (between the >> spars) is essentially a flat area, could I lay up a fiberglass >> "sheet" on a table that, once dried, could be cut to fit and bonded >> as done with wing skins? That way, it seems that the need to >> "refoam" the wing could be dispensed with. Comments? > >I don't think I'd do it that way. A layer or two of fiberglass has >just about no stiffness to it without some foam underneath. I think >you could almost count on it deforming just due to airloads. It's >awfully easy to stuff some foam in there and sand to shape, or use some >2 part urethane poured into the holes (if the thing is upside down) and >then sand to shape. Or if it's right side up, you could use sheet foam >and 2 part urethane to hold it in place. You're going to need to rough >up the area around the hole anyway, and you'd be doing that as you >sanded the foam to conform to the airfoil shape. > >Mark Langford, Huntsville, Alabama >N56ML "at" hiwaay.net >see KR2S project at http://home.hiwaay.net/~langford > > > >_______________________________________ >to UNsubscribe from KRnet, send a message to KRnet-leave@mylist.net >please see other KRnet info at http://www.krnet.org/info.html > ------------------------------ Message: 11 Date: Sat, 10 Apr 2004 16:34:29 +0200 From: "Stephen Jacobs" Subject: RE: KR> Stephen Jacobs To: "'KRnet'" Message-ID: <001f01c41f08$f1d4c8b0$2064a8c0@homedesktop> Content-Type: text/plain; charset="us-ascii" Thanks Eric - I will contact them. Beste Steve ------------------------------ Message: 12 Date: Sat, 10 Apr 2004 12:12:28 -0400 From: "Doug Rupert" Subject: RE: KR> Stick linkages To: "'KRnet'" Message-ID: <007401c41f16$9f664dc0$ae3cd0d8@office> Content-Type: text/plain; charset="us-ascii" Phillip: Please send me a copy of those plans off the list as I plan on converting the KR2S into a single seater with side stick controls. Makes for a roomier cabin instead of shoe horning two people into such a small space. With the AS wings, dual wing tanks, and a few other small mods I believe this arrangement would satisfy most of the Walter Mitty type fighter pilots in us all, not to mention one hell on a fun machine to fly. Doug Rupert Simcoe Ontario -----Original Message----- From: krnet-bounces@mylist.net [mailto:krnet-bounces@mylist.net] On Behalf Of Phillip Matheson Sent: Friday, April 09, 2004 11:48 PM To: KRnet Subject: Re: KR> Stick linkages For the last couple of weeks I have been working on my stick design to hook up to my aileron bellcranks converted for push tubes -0--------------------- Steve I may be able to help with drawings of a single stick, and push rods. to belcrank. I would have to post them, after coping. Phillip Matheson matheson@dodo.com.au Australia VH PKR See our engines and kits at. http://www.vw-engines.com/ http://www.homebuilt-aviation.com/ See my KR at Mark Jones web http://mywebpage.netscape.com/n886mj/pmkr2.html _______________________________________ to UNsubscribe from KRnet, send a message to KRnet-leave@mylist.net please see other KRnet info at http://www.krnet.org/info.html ------------------------------ Message: 13 Date: Sat, 10 Apr 2004 12:14:08 -0500 From: "Mark Jones" Subject: KR> Weigh in update. To: "KR Net" , "Corvaircraft" Message-ID: <004101c41f1f$3cc97760$6401a8c0@wi.rr.com> Content-Type: text/plain; charset="iso-8859-1" I have just weighed my plane again. This is less the outboard wings. Otherwise, it is basically a completed fuselage. If I had wings I could fly. Anyway, here are the weights. Left Main: 180 lbs. Nose Wheel: 183 lbs. Right Main: 174 lbs. Total Weight: 537 lbs. Thai is an increase of only 24 lbs since my last weigh in back in September of 2003. Not too shabby. Mark Jones (N886MJ) Wales, WI USA E-mail me at flykr2s@wi.rr.com Visit my KR-2S CorvAIRCRAFT web site at http://mywebpage.netscape.com/n886mj/homepage.html ------------------------------ Message: 14 Date: Sat, 10 Apr 2004 19:08:00 +0100 (BST) From: Edward Seaman Subject: Re: KR> Elevator Mass Balance mounting To: KRnet Message-ID: <20040410180800.70161.qmail@web25107.mail.ukl.yahoo.com> Content-Type: text/plain; charset=iso-8859-1 Joe says Weight on the ends distributes more effectively when dynamic forces are applied. I have used this method on the last aircraft I built(not a KR). Ed says - Weight on the "ends" is at an extremity - very far from evenly distributed. This extremeity is the furthest possible distance from the input force (control rod) and will thus precipitate the max torsional load - not a good idea. Steve J - please copy me on the info by Tony B - the guy that talks from the right end. Edward (edpseaman@yahoo.co.uk) ____________________________________________________________ Yahoo! Messenger - Communicate instantly..."Ping" your friends today! Download Messenger Now http://uk.messenger.yahoo.com/download/index.html ------------------------------ Message: 15 Date: Sat, 10 Apr 2004 16:02:55 -0400 From: "Colin & Bev Rainey" Subject: KR> Supercharging vs Turbocharging To: "KRnet" Message-ID: <00b001c41f36$d04ae200$99ef0843@RaineyDay> Content-Type: text/plain; charset="iso-8859-1" Doug & netters, The main reason for using a turbo instead of the supercharger is that a supercharger relies on cannibalizing horsepower from the engine to make horsepower, where the turbo uses "free" horsepower derived from the exhaust pulses of the engine. The supercharger renders horsepower at the cost of some, and they are not controllable for the amount of boost like the turbo is. They are usually configured and then "on" all the time. Turbos can be set so to speak. Typically where people run into problems with overheating and such is 1) the restriction in the free flowing exhaust "backs up" heat into the engine, & 2) the heat introduced into the fuel/air mixture due to the heat generated from compressing the air. Number one complaint has typically been solved by increasing air flow around the exhaust area, and making boost at higher rpms where the momentum of the turbo can be sufficiently built up to actually begin to help scavenge exhaust out of the engine. Number 2 is dealt with by using low compression pistons, higher octane fuel, delayed turbo response, intercoolers, or combinations of those things. All that having been said, and at the risk of making an oversimplification, if one were to use the ONLY for normalizing the engine, and therefore have a manual wastegate that allowed the pilot to only "activate" the turbo above a density altitude of say 3-4000 feet, than the engine should just behave as if it was still at those altitudes, if one did not allow the manifold pressure to grow beyond the inches that are experienced below that altitude. One would then "trick" the engine into believing it was still down lower. I think most problems are encountered when the temptation to try and tap the additional performance increases offered by the turbo at lower altitudes that gets most pilots into trouble. The additional heat, AT ALTITUDE would be a beneficial thing, both being added to the cowling temp, and the mixture, as it would help the engine from being too cool at altitude (above say 5000feet), and would assist in good air/fuel atomization or mixing as well. Remember, even in our modern cars, there is a certain amount of engine heat that must be added to the air/fuel mixture in order to prevent the gasoline from "falling out" of the mix due to condensation within the intake manifold. This is where some have had tuning problems due to the surging and rich/lean running because the fuel falls out and then puddles, then gets sucked into the next cylinder as too rich and the engine surges, and cuts out, sometimes minor, sometimes major. One other caution about turbos: make sure you know what kind you have, blow through, or draw through. A blow through design lacks the seal necessary to draw air/fuel mixture through the carb, where the turbo would be mounted AFTER the carb, but before the engine. The other design draw through has these seals. Most turbos are the blow through design, and draw outside air in, then compress it and send it on to the carb or fuel injection system. Also turbos typically allow for the elimination of any kind of muffler due to their quieting effect. Flame as necessary......lol Colin & Bev Rainey KR2(td) N96TA Sanford, FL crainey1@cfl.rr.com or crbrn96ta@hotmail.com http://kr-builder.org/Colin/index.html ------------------------------ Message: 16 Date: Sat, 10 Apr 2004 19:08:50 -0400 From: "Jack Cooper" Subject: RE: KR> Diehl Gear To: "KRnet" Message-ID: <410-22004461023850359@earthlink.net> Content-Type: text/plain; charset=US-ASCII Garrie asked My next question is, does anyone have Diehl tri-gear for sale and > how does it stand up to roughish grass/dirt strips? Garrie My friend Gene Byrd had Deihl Trigear on his KR-2S and routinely flew off his private grass strip. Prior to his crash he had changed out the tube on the nose wheel because it was bent just above the fork. Gene told me that Dan Diehl said that it would happen again if he continued to fly off rough strips. With Gene's experience I would use conventional (tail dragger) gear if I were planning to routinely fly from a rough grass field. Just my 2 cents. Jack Cooper kr2cooper@earthlink.net _______________________________________ > to UNsubscribe from KRnet, send a message to KRnet-leave@mylist.net > please see other KRnet info at http://www.krnet.org/info.html ------------------------------ Message: 17 Date: Sat, 10 Apr 2004 16:49:20 -0700 From: "joe" Subject: Re: KR> Elevator Mass Balance mounting To: "KRnet" Message-ID: <001001c41f56$71ab0b60$0a0110ac@o7p4e3> Content-Type: text/plain; charset="iso-8859-1" Ed, I apologize for being so vague. I didn't mean to imply that "all" counter balance weights were on the ends. But, actually the same as Ed indicated. The word "effectively" was a poor choice of words. However, the aircraft that I built came with weights and most of the weight was at the ends. The aircraft had a canard. Joe ----- Original Message ----- From: "Edward Seaman" To: "KRnet" Sent: Saturday, April 10, 2004 11:08 AM Subject: Re: KR> Elevator Mass Balance mounting > Joe says > > Weight on the ends distributes more effectively when > dynamic forces are applied. I have used this method on > the last aircraft I built(not a KR). > > > Ed says - Weight on the "ends" is at an extremity - > very far from evenly distributed. This extremeity is > the furthest possible distance from the input force > (control rod) and will thus precipitate the max > torsional load - not a good idea. > > Steve J - please copy me on the info by Tony B - the > guy that talks from the right end. > > Edward (edpseaman@yahoo.co.uk) > > > > > > > > > > > > > ____________________________________________________________ > Yahoo! Messenger - Communicate instantly..."Ping" > your friends today! Download Messenger Now > http://uk.messenger.yahoo.com/download/index.html > > _______________________________________ > to UNsubscribe from KRnet, send a message to KRnet-leave@mylist.net > please see other KRnet info at http://www.krnet.org/info.html ------------------------------ Message: 18 Date: Sat, 10 Apr 2004 16:56:38 -0700 From: "joe" Subject: Re: KR> Elevator Mass Balance mounting To: "KRnet" Message-ID: <002401c41f57$76f378e0$0a0110ac@o7p4e3> Content-Type: text/plain; charset="iso-8859-1" Ed, My old construction webpage has been removed. However, you can find something similar at http://www.velocityxl.com/Canard.htm ----- Original Message ----- From: "Edward Seaman" To: "KRnet" Sent: Saturday, April 10, 2004 11:08 AM Subject: Re: KR> Elevator Mass Balance mounting > Joe says > > Weight on the ends distributes more effectively when > dynamic forces are applied. I have used this method on > the last aircraft I built(not a KR). > > > Ed says - Weight on the "ends" is at an extremity - > very far from evenly distributed. This extremeity is > the furthest possible distance from the input force > (control rod) and will thus precipitate the max > torsional load - not a good idea. > > Steve J - please copy me on the info by Tony B - the > guy that talks from the right end. > > Edward (edpseaman@yahoo.co.uk) > > > > > > > > > > > > > ____________________________________________________________ > Yahoo! Messenger - Communicate instantly..."Ping" > your friends today! Download Messenger Now > http://uk.messenger.yahoo.com/download/index.html > > _______________________________________ > to UNsubscribe from KRnet, send a message to KRnet-leave@mylist.net > please see other KRnet info at http://www.krnet.org/info.html ------------------------------ Message: 19 Date: Sat, 10 Apr 2004 17:12:19 -0700 From: "joe" Subject: Re: KR> Elevator Mass Balance mounting To: "KRnet" Message-ID: <004801c41f59$a76ceae0$0a0110ac@o7p4e3> Content-Type: text/plain; charset="iso-8859-1" I did not say outboard ends, I said ends. ----- Original Message ----- From: "joe" To: "KRnet" Sent: Saturday, April 10, 2004 4:56 PM Subject: Re: KR> Elevator Mass Balance mounting > Ed, > My old construction webpage has been removed. > However, you can find something similar at > http://www.velocityxl.com/Canard.htm > > ----- Original Message ----- > From: "Edward Seaman" > To: "KRnet" > Sent: Saturday, April 10, 2004 11:08 AM > Subject: Re: KR> Elevator Mass Balance mounting > > > > Joe says > > > > Weight on the ends distributes more effectively when > > dynamic forces are applied. I have used this method on > > the last aircraft I built(not a KR). > > > > > > Ed says - Weight on the "ends" is at an extremity - > > very far from evenly distributed. This extremeity is > > the furthest possible distance from the input force > > (control rod) and will thus precipitate the max > > torsional load - not a good idea. > > > > Steve J - please copy me on the info by Tony B - the > > guy that talks from the right end. > > > > Edward (edpseaman@yahoo.co.uk) > > > > > > > > > > > > > > > > > > > > > > > > > > ____________________________________________________________ > > Yahoo! Messenger - Communicate instantly..."Ping" > > your friends today! Download Messenger Now > > http://uk.messenger.yahoo.com/download/index.html > > > > _______________________________________ > > to UNsubscribe from KRnet, send a message to KRnet-leave@mylist.net > > please see other KRnet info at http://www.krnet.org/info.html > > _______________________________________ > to UNsubscribe from KRnet, send a message to KRnet-leave@mylist.net > please see other KRnet info at http://www.krnet.org/info.html ------------------------------ Message: 20 Date: Sat, 10 Apr 2004 21:20:35 -0400 From: "Doug Rupert" Subject: RE: KR> Supercharging vs Turbocharging To: "'KRnet'" Message-ID: <001c01c41f63$31ff1300$6df5e2d1@office> Content-Type: text/plain; charset="us-ascii" Colin: True that the supercharger uses horsepower, as does every other thing hanging off the accessory case. Unlike a turbo however the power increase is there from the get go. A turbo depends upon high revs to produce power which increases the wear on an engine. The supercharger however produces most of it's power at lower rpm's where we tend to normally operate. The supercharger has been used for many years and in WW2 many of the fighter aircraft used them sometimes in tandem, most notably the British Spitfire and American P51 Mustang. The point that they are not controllable is not true as they can be set up either at the factory by the manufacturer to operate in a certain boost range or can be manually controlled with a waste gate much the same as a turbo. The main advantage to the supercharger over the turbo however comes when the throttle is opened up. The supercharger is working right now, whereas it takes time for the turbo to spool up and develop its power, much the same as a jet engine. As you can see this could be a deadly situation as in a missed approach or another emergency when instant power is required. The turbo does create horsepower, yes but the supercharger on the other hand produces not only horsepower but more importantly torque, and that when all is said and done is what is needed to swing that overgrown fan on the nose of the aircraft. What it really comes down to however remains a personal choice. I have used both superchargers and turbos over the years and both work well but in the case of an aircraft type application I believe one would be more satisfied with the results obtained from using the supercharger. This would be an excellent time for Mr. Hoover to chime in here as he has flown aircraft that have been equipped with superchargers and I for one would be very interested in his input on the subject. Doug Rupert Simcoe Ontario -----Original Message----- From: krnet-bounces@mylist.net [mailto:krnet-bounces@mylist.net] On Behalf Of Colin & Bev Rainey Sent: Saturday, April 10, 2004 4:03 PM To: KRnet Subject: KR> Supercharging vs Turbocharging Doug & netters, The main reason for using a turbo instead of the supercharger is that a supercharger relies on cannibalizing horsepower from the engine to make horsepower, where the turbo uses "free" horsepower derived from the exhaust pulses of the engine. The supercharger renders horsepower at the cost of some, and they are not controllable for the amount of boost like the turbo is. They are usually configured and then "on" all the time. Turbos can be set so to speak. Typically where people run into problems with overheating and such is 1) the restriction in the free flowing exhaust "backs up" heat into the engine, & 2) the heat introduced into the fuel/air mixture due to the heat generated from compressing the air. Number one complaint has typically been solved by increasing air flow around the exhaust area, and making boost at higher rpms where the momentum of the turbo can be sufficiently built up to actually begin to help scavenge exhaust out of the engine. Number 2 is dealt with by using low compression pistons, higher octane fuel, delayed turbo response, intercoolers, or combinations of those things. All that having been said, and at the risk of making an oversimplification, if one were to use the ONLY for normalizing the engine, and therefore have a manual wastegate that allowed the pilot to only "activate" the turbo above a density altitude of say 3-4000 feet, than the engine should just behave as if it was still at those altitudes, if one did not allow the manifold pressure to grow beyond the inches that are experienced below that altitude. One would then "trick" the engine into believing it was still down lower. I think most problems are encountered when the temptation to try and tap the additional performance increases offered by the turbo at lower altitudes that gets most pilots into trouble. The additional heat, AT ALTITUDE would be a beneficial thing, both being added to the cowling temp, and the mixture, as it would help the engine from being too cool at altitude (above say 5000feet), and would assist in good air/fuel atomization or mixing as well. Remember, even in our modern cars, there is a certain amount of engine heat that must be added to the air/fuel mixture in order to prevent the gasoline from "falling out" of the mix due to condensation within the intake manifold. This is where some have had tuning problems due to the surging and rich/lean running because the fuel falls out and then puddles, then gets sucked into the next cylinder as too rich and the engine surges, and cuts out, sometimes minor, sometimes major. One other caution about turbos: make sure you know what kind you have, blow through, or draw through. A blow through design lacks the seal necessary to draw air/fuel mixture through the carb, where the turbo would be mounted AFTER the carb, but before the engine. The other design draw through has these seals. Most turbos are the blow through design, and draw outside air in, then compress it and send it on to the carb or fuel injection system. Also turbos typically allow for the elimination of any kind of muffler due to their quieting effect. Flame as necessary......lol Colin & Bev Rainey KR2(td) N96TA Sanford, FL crainey1@cfl.rr.com or crbrn96ta@hotmail.com http://kr-builder.org/Colin/index.html _______________________________________ to UNsubscribe from KRnet, send a message to KRnet-leave@mylist.net please see other KRnet info at http://www.krnet.org/info.html ------------------------------ _______________________________________________ See KRnet list details at http://www.krnet.org/instructions.html End of KRnet Digest, Vol 346, Issue 19 ************************************** ================================== ABC Amber Outlook Converter v4.20 Trial version ==================================