---------------------------------------------------------- RV-List Digest Archive --- Total Messages Posted Sat 12/04/04: 25 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:18 AM - Re: Polishing Aluminum (Doug Gray) 2. 05:01 AM - Re: Polishing Aluminum (Wayne R. Couture) 3. 07:40 AM - Re: Polishing Aluminum (Charlie England) 4. 07:48 AM - Re: Polishing Aluminum (Evan and Megan Johnson) 5. 07:49 AM - EGT increase (Bluecavu@aol.com) 6. 07:50 AM - Re: RV-List Digest: 35 Msgs - 12/03/04 (Mlfred@aol.com) 7. 07:53 AM - Re: EGT(ease) (Skylor Piper) 8. 09:37 AM - Re: Re: RV-List Digest: 35 Msgs - 12/03/04 (Scott Jackson) 9. 09:38 AM - Re: Cleaning an engine (HAL KEMPTHORNE) 10. 09:39 AM - Re: Polishing Aluminum (Kosta Lewis) 11. 10:48 AM - Engine overhaul (David L Ahrens) 12. 10:53 AM - Re: [Bulk] Rv-List Power Required (Kevin Horton) 13. 11:08 AM - Re: Cleaning an engine (RV_8 Pilot) 14. 03:42 PM - air oil separator (Wheeler North) 15. 03:42 PM - Stick grips (lyle) 16. 04:21 PM - RV-8 Canopy Latch (William Davis) 17. 04:33 PM - Re: Re: RV-List Digest: 35 Msgs - 12/03/04 (Kevin Horton) 18. 04:47 PM - Re: [Bulk] Rv-List Power Required (Hopperdhh@aol.com) 19. 05:15 PM - Re: [Bulk] Rv-List Power Required (Alex Peterson) 20. 05:53 PM - Re: Stick grips (Dan Checkoway) 21. 06:16 PM - Re: [Bulk] Rv-List Power Required (Kevin Horton) 22. 06:17 PM - Re: [Bulk] Rv-List Power Required (Jack Ford) 23. 06:19 PM - Re: Stick grips (Bobby Hester) 24. 07:48 PM - Re: air oil separator (richard dudley) 25. 08:15 PM - Re: air oil separator (Dan Checkoway) ________________________________ Message 1 _____________________________________ Time: 03:18:53 AM PST US From: Doug Gray Subject: Re: RV-List: Polishing Aluminum --> RV-List message posted by: Doug Gray I tried polishing a small area of my unfinished fuselage with 'silvo' silver polish (for cutlery and fine silverware) and it was too easy. A small area that I had scotchbrited came back to a mirror shine in 15-30 seconds of light rubbing using a hand cloth. I'd love to know what is in this product. I could imagine doing the whole aircraft in far less time than it would take to prep for painting. The label says it is good for aluminium but carries little other information. Do polished aircraft normally get a coat of clear to protect the finish or are they left bare Al? Doug Gray Sydney, Australia ________________________________ Message 2 _____________________________________ Time: 05:01:56 AM PST US From: "Wayne R. Couture" Subject: Re: RV-List: Polishing Aluminum --> RV-List message posted by: "Wayne R. Couture" I think you may be mistaken about the time your polish job will last. I talked to a few people about there polished airplanes and they said they have to re-polish about every two weeks! Too much work for me though I don't have any first hand experience. Wayne do not archive ----- Original Message ----- From: "Amit Dagan" Subject: RV-List: Polishing Aluminum > --> RV-List message posted by: "Amit Dagan" > > Listers, > I would like to start a thread about polishing unpainted aluminum, > specificaly I want to hear from RV builders/owners who have a polished RV, > or a combination of partly painted and partly polished. > I have done a little research into the chemicals (compounds) and tools > (polishers, compounders, cloth, etc.) that the Temco/Swift and the > Airstream-Trailer folks use. > At this point it seems to me that polishing an RV is much cheaper than > painting it, even if you do it yourself, plus it will not add any > considerable weight, while painting adds 10-40 pounds to the empty weight of > the craft (by several accounts). Polished aluminum does need some > maintenance, but after the first "big job" (which still sounds like takes > less time than painting) it sounds like it only takes 1-2 days a year to > keep up a nice shine. > I understand that the fiberglass parts (tips, cowl, etc.) need to be painted > "anyway", so maybe there's a valid argument for "just have it all painted, > and be done with it", and personal taste might play a great part in favoring > paint over polished aluminum, but, and here is my real question (Finally... > thanks for bearing with me so far): > Are there any other considerations I am missing? > Amit, > 65 hours of flying with bare, unpolished aluminum. > > http://toolbar.msn.click-url.com/go/onm00200415ave/direct/01/ > > ________________________________ Message 3 _____________________________________ Time: 07:40:17 AM PST US From: Charlie England Subject: Re: RV-List: Polishing Aluminum --> RV-List message posted by: Charlie England Amit Dagan wrote: >--> RV-List message posted by: "Amit Dagan" > >Listers, >I would like to start a thread about polishing unpainted aluminum, >specificaly I want to hear from RV builders/owners who have a polished RV, >or a combination of partly painted and partly polished. >I have done a little research into the chemicals (compounds) and tools >(polishers, compounders, cloth, etc.) that the Temco/Swift and the >Airstream-Trailer folks use. >At this point it seems to me that polishing an RV is much cheaper than >painting it, even if you do it yourself, plus it will not add any >considerable weight, while painting adds 10-40 pounds to the empty weight of >the craft (by several accounts). Polished aluminum does need some >maintenance, but after the first "big job" (which still sounds like takes >less time than painting) it sounds like it only takes 1-2 days a year to >keep up a nice shine. >I understand that the fiberglass parts (tips, cowl, etc.) need to be painted >"anyway", so maybe there's a valid argument for "just have it all painted, >and be done with it", and personal taste might play a great part in favoring >paint over polished aluminum, but, and here is my real question (Finally... >thanks for bearing with me so far): >Are there any other considerations I am missing? >Amit, >65 hours of flying with bare, unpolished aluminum. > >http://toolbar.msn.click-url.com/go/onm00200415ave/direct/01/ > The polished Swift on the cover of Sport Aviation 8 or 10 years ago lived in a hangar here at Slobovia Outernational for a while. It was kept under a custom cover in a closed hangar. If it was never flown, it would go for maybe 2 months without polishing. Polishing was an all-day job with a power buffer. Being based on a grass strip, it stayed in the hangar many, many days when everyone else went flying & just rinsed off the mud after flying. I guess there are 3 choices. Unpainted for light weight, easy to clean & ok looking. Painted for better looking, slightly heavier & easy to clean. Polished for drop dead gorgeous but effectively unflyable. :-) Ya pays yer money & ya takes yer choice... Charlie ________________________________ Message 4 _____________________________________ Time: 07:48:57 AM PST US From: "Evan and Megan Johnson" Subject: Re: RV-List: Polishing Aluminum --> RV-List message posted by: "Evan and Megan Johnson" One big reason not to polish is that you cant hide any of your mistakes. I understand that you built a fabulous airframe....I was told specifically to look for your plane at the homecoming......but the rest of us hmmm... I actually feel like my project is coming out pretty good, but I know where the flaws are. If I dont fix them they will just stare at me everytime I look at the plane. As for the fiberglass, you may remember a post a couple of months ago with a link to some pretty cool chrome paint. I looked at the website and I doubt it would be as shiney as polished aluminum, but its as good as I have ever seen....Link below:http://www.alsacorp.com/chrome.htm Evan www.evansaviationproducts.com ----- Original Message ----- From: "Amit Dagan" Subject: RV-List: Polishing Aluminum > --> RV-List message posted by: "Amit Dagan" > > Listers, > I would like to start a thread about polishing unpainted aluminum, > specificaly I want to hear from RV builders/owners who have a polished RV, > or a combination of partly painted and partly polished. > I have done a little research into the chemicals (compounds) and tools > (polishers, compounders, cloth, etc.) that the Temco/Swift and the > Airstream-Trailer folks use. > At this point it seems to me that polishing an RV is much cheaper than > painting it, even if you do it yourself, plus it will not add any > considerable weight, while painting adds 10-40 pounds to the empty weight of > the craft (by several accounts). Polished aluminum does need some > maintenance, but after the first "big job" (which still sounds like takes > less time than painting) it sounds like it only takes 1-2 days a year to > keep up a nice shine. > I understand that the fiberglass parts (tips, cowl, etc.) need to be painted > "anyway", so maybe there's a valid argument for "just have it all painted, > and be done with it", and personal taste might play a great part in favoring > paint over polished aluminum, but, and here is my real question (Finally... > thanks for bearing with me so far): > Are there any other considerations I am missing? > Amit, > 65 hours of flying with bare, unpolished aluminum. > > http://toolbar.msn.click-url.com/go/onm00200415ave/direct/01/ > > ________________________________ Message 5 _____________________________________ Time: 07:49:32 AM PST US From: Bluecavu@aol.com Subject: RV-List: EGT increase --> RV-List message posted by: Bluecavu@aol.com I'm sure you considered that an intake leak can cause a sudden elevation in EGT on the affected cyls... might check your hose couplings, etc. Scott N4ZW do not archive ________________________________ Message 6 _____________________________________ Time: 07:50:50 AM PST US From: Mlfred@aol.com Subject: RV-List: Re: RV-List Digest: 35 Msgs - 12/03/04 --> RV-List message posted by: Mlfred@aol.com In a message dated 12/4/2004 4:14:26 AM Central Standard Time, rv-list-digest@matronics.com writes: The basic point remains, you need more power to maintain the same CAS at a higher altitude. Jim Oke Wpg., MB I beg your pardon if I show my ignorance here. 2100RPM/23"MP = 9.5GPH (most of the time --varies slightly with temps), and this shows about 165KIAS on the ASI in my F1 (not calibrated by any means). This seems to be the case at 2000'MSL or 8000'MSL. I do see a difference in GS (increases with altitude), if the wind factor is removed. This seems to refute the 'takes more power at altitude' argument: I get an increase in GS with no increase in fuel flow...and I have always thought fuel flow in GPH x ~14 = HP when operating LOP for the 8.5 comp engines. Now, in looking at the P&W R985 power charts, it shows a lower MP (and fuel flow) at higher altitudes to get the same power -- I recall this is due to the lower ambient pressure in the crankcase..along with the lower ambient pres seen by the exhaust system. So, it would seem that the power chart tells us that it takes a lower fuel flow to get the same power at a higher altitude...so, if the flow remains constant, you would be seeing a power increase? It's getting a bit nebulous now... 'splain it to me (again), Lucy. What I have seen in 6000hrs of flying tells me higher = faster = cheaper, at least on longer trips where the extra fuel for the climb can be eliminated by the greater efficiency of flight at a higher altitude. It may be that flying higher in a turbo- or supercharged engine starts to allow the blower to use some percentage of the produced HP to operate the blower itself -- could this be the source of the higher power required to fly at the same CAS at 22,000MSL? I recall the automotive blower folks telling me that a blown engine uses more fuel per HP when under boost...but the efficiency charts for the big round motors doesn't show that same drop off... So, help me understand this, one more time... Cheers Mark ________________________________ Message 7 _____________________________________ Time: 07:53:37 AM PST US DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; b=EwnYX+dS6OSkcFBLTdfEWXcr9fsOcqRWsCXooNx2BZjBxhN/0zcWxosmu0X5h5yf8X7n3yFEm+kbUFg7SSGVyfcGFaL6yq/re7oM1cins3TKydLvVXesAqXMunlZsJ58g6mE0Ma9RBh5Kkrfpgnp8yfIfeqQ9uMpNrbB3J3Y/Fw= ; From: Skylor Piper Subject: Re: RV-List: EGT(ease) --> RV-List message posted by: Skylor Piper Try adding carb heat. Many carbureted engines WILL run lean of peak with the addition of some carb heat to assist with the fuel atomization. The amount of carb heat varies from engine to engine. Some will do it with just a little heat, and others require nearly full heat. A temperature probe in the carb can help with this. 70 degrees is about the ideal throat temperature for ideal carburetor performance --- Fiveonepw@aol.com wrote: > --> RV-List message posted by: Fiveonepw@aol.com > > So while we're on the subject.... > > As I lean my carbureted E3D, the EGTs continue to > climb until the engine goes > rough. Will I ever see 50 deg. lean of peak? 8-( > > What's going on here? > > From The PossumWorks > Mark & do not archive mindless > questions............. > > > > Click on the > this > by the > Admin. > _-> > Contributions > any other > Forums. > > http://www.matronics.com/subscription > http://www.matronics.com/FAQ/RV-List.htm > http://www.matronics.com/archives > http://www.matronics.com/photoshare > http://www.matronics.com/emaillists > > > > > > __________________________________ http://my.yahoo.com ________________________________ Message 8 _____________________________________ Time: 09:37:53 AM PST US From: "Scott Jackson" Subject: Re: RV-List: Re: RV-List Digest: 35 Msgs - 12/03/04 --> RV-List message posted by: "Scott Jackson" I think we're reading too much into this. It isn't rocket science. We're using engines that were designed in the late 20's to run unattended all day long turning agricultural pumps in the southern States; aviation use was initially just a spin-off of this. As far as the airplane can sense, there is no reduced drag at altitude, remember our elementary balancing of forces for unaccelerated flight: the airplane will just keep accelerating until the total drag equals the thrust produced by the engine/propellor package at the power output we've decided upon. If we want to cruise at 75% power, then our best TAS would be at the highest altitude that the engine can still produce that power, and the throttle plate would be wide-open, and I recently discovered from an engineer that that reduces efficiency losses in the intake system. If we wanted to cruise at 65%, then the altitude would be a little higher and the IAS would be a little lower, but the TAS might not be much different from that at the 75%-power altitude, as it increases with altitude, but the fuel flow would be commensurately less, as we're asking less power of the engine. And so on for 55%, etc. There's no free lunch. of course, we have to burn extra fuel to lift ourselves higher. To include the wind component in this, the simplest way of finding the most-efficient altitude-mpg speaking- for each leg flown,would be to start at the altitude that the engine can only produce the cruising power we desire with full throttle, then continue a slow drift upwards while watching the instantaneous groundspeed readout on the GPS. Once it starts to decrease, return to the altitude at which it peaked. This simplifies the TAS/GS/fuel flow solution to child's play. I hate to admit that flying the latest-generation airliners, with dual FMGC and lots of fuel-predicting algorithms, I still use the old groundspeed-over fuel-flow ratio on my circular slide rule ,which reflects the real world out there, not the idealized atmospheric models the computers use, and nearly always beat the predictions for fuel-over destination and trip burn. Not bragging by anymeans, just trying to keep this simple, folks. As we keep telling ourselves at "work", "Hey, it might be all-glass and full-time, fly-by-wire, but it's still just an airplane!" Scott in Vancouver ----- Original Message ----- From: Subject: RV-List: Re: RV-List Digest: 35 Msgs - 12/03/04 > --> RV-List message posted by: Mlfred@aol.com > > > In a message dated 12/4/2004 4:14:26 AM Central Standard Time, > rv-list-digest@matronics.com writes: > > The basic point remains, you need more power to maintain the same CAS at > a > higher altitude. > > Jim Oke > Wpg., MB > > > I beg your pardon if I show my ignorance here. > > 2100RPM/23"MP = 9.5GPH (most of the time --varies slightly with temps), > and > this shows about 165KIAS on the ASI in my F1 (not calibrated by any > means). > This seems to be the case at 2000'MSL or 8000'MSL. I do see a difference > in GS > (increases with altitude), if the wind factor is removed. > > This seems to refute the 'takes more power at altitude' argument: I get > an > increase in GS with no increase in fuel flow...and I have always thought > fuel > flow in GPH x ~14 = HP when operating LOP for the 8.5 comp engines. > > Now, in looking at the P&W R985 power charts, it shows a lower MP (and > fuel > flow) at higher altitudes to get the same power -- I recall this is due > to > the lower ambient pressure in the crankcase..along with the lower ambient > pres > seen by the exhaust system. > > So, it would seem that the power chart tells us that it takes a lower fuel > flow to get the same power at a higher altitude...so, if the flow remains > constant, you would be seeing a power increase? > > It's getting a bit nebulous now... 'splain it to me (again), Lucy. What I > have seen in 6000hrs of flying tells me higher = faster = cheaper, at > least on > longer trips where the extra fuel for the climb can be eliminated by the > greater efficiency of flight at a higher altitude. > > It may be that flying higher in a turbo- or supercharged engine starts to > allow the blower to use some percentage of the produced HP to operate the > blower > itself -- could this be the source of the higher power required to fly at > the same CAS at 22,000MSL? I recall the automotive blower folks telling > me that > a blown engine uses more fuel per HP when under boost...but the > efficiency > charts for the big round motors doesn't show that same drop off... > > So, help me understand this, one more time... > > Cheers > Mark > > > ________________________________ Message 9 _____________________________________ Time: 09:38:24 AM PST US From: HAL KEMPTHORNE Subject: Re: RV-List: Cleaning an engine --> RV-List message posted by: HAL KEMPTHORNE RV_8 Pilot wrote: Have used some of the water based detergent cleaners from the auto parts store, but the old timers cringe when mentioning use of water/water based cleaners (out of concern for unnecessary corrosion. Hi all, Some detergent cleaners, maybe most, corrode aluminum. If the use of water to clean the engine causes corrosion, what does flying in rain do? I've heard Woolite recommended. I always fly after a wash. I've heard Air Force forbids use of Simple Green but I know several who use it regularly and their planes look great. I imagine they do a thorough water rinse. hal ________________________________ Message 10 ____________________________________ Time: 09:39:28 AM PST US From: "Kosta Lewis" Subject: RE: RV-List: Polishing Aluminum --> RV-List message posted by: "Kosta Lewis" Gordon Comfort would be the resident expert on polished RVs. Someone discussed a polished RV-4 a while back parked on the ramp and the reflection from the wing wrinkled the canopy. There was a beeeutiful polished Cessna C-170B at OSH every year belonging to the Applegates that was traded up for an also beeeutiful C-195 that is painted. Harv said he is pretty happy to have a painted airplane and would not go back to the polishing. I think it depends on what you want your airplane to be: show plane or play-horse. Fly for one polish for six. I know at least one airplane that has been flying around in VeriPrime for 7 years now................ March '93 Sport Aviation has David Anders' polished RV on the cover if you want to know what a Reserve Grand Champion looked like at the time. Michael ________________________________ Message 11 ____________________________________ Time: 10:48:51 AM PST US Subject: RV-List: Engine overhaul From: David L Ahrens --> RV-List message posted by: David L Ahrens Hello list members: I am rebuilding a 0-320B3B. I have most of the parts that I need except for the camshaft. The question I have is, can I change to the camshaft with the intergal gear? I have the parts book and know the different parts that are required at the tach drive end. I am concerned about the possible need to change out the accessory case because of oil slinger, etc.. I have not been able to locate a copy of Lycoming Service Letter 1218A that addresses the conversion. Can anyone help? Thanks and happy holidays, David Ahrens, RV6A ________________________________ Message 12 ____________________________________ Time: 10:53:39 AM PST US From: Kevin Horton Subject: RE: [Bulk] RV-List: Rv-List Power Required --> RV-List message posted by: Kevin Horton At 7:41 -0600 3/12/04, you wrote: >--> RV-List message posted by: "Alex Peterson" > >> 10. There being no free lunch in this line of business, you >> either need a >> bigger engine or run more fuel through the same engine. >> > >There are indeed free lunches with respect to flying higher. Many factors >apply, but most normally aspirated piston planes get their best economy >(which is another way of saying speed per gallon) at something around 7 - 8 >thousand feet. Obviously, if a trip is only 50 miles, there may not be a >net benefit. Jets run high because for the same indicated airspeed, which >approximately translates to power needed, they have a much higher TAS. I'll >let the jet jockeys chime in here, but the fuel burns in jets go way up at >lower altitudes, TAS the same. > >I will run some tests soon, setting some constant power (this means basic >power settings are the same, and fuel flow and egt relative to peak must be >identical), fly a high and low altitude run, and take data. A complication >to this is that the temperature will not be the same at, for example, 2000' >vs 7500'. In any case, the output of this test will be to calculate TAS >based upon temperature, IAS, barometer and altitude. > I was on the road without e-mail access since early in this thread. It looks like Ed's questions have been pretty much answered, I think. One comment on your plan Alex - if you want the same power at different altitudes, the MP will be a bit lower at the higher altitude. The power chart from a 250 Commanche POH that Tom Gummo posted illustrates this effect well. -- Kevin Horton RV-8 (finishing kit) Ottawa, Canada http://go.phpwebhosting.com/~khorton/rv8/ ________________________________ Message 13 ____________________________________ Time: 11:08:19 AM PST US From: "RV_8 Pilot" Subject: Re: RV-List: Cleaning an engine --> RV-List message posted by: "RV_8 Pilot" I generally rinse off any detergents used on anything. As for the water, your point is well taken but it is typically not splashed (with a cowled & baffled arrgt) across your magnetos, spark plug connectors, firewall mounted components when flying through rain. Bryan >Some detergent cleaners, maybe most, corrode aluminum. If the use of water >to clean the engine causes corrosion, what does flying in rain do? I've >heard Woolite recommended. I always fly after a wash. > >I've heard Air Force forbids use of Simple Green but I know several who use >it regularly and their planes look great. I imagine they do a thorough >water rinse. > >hal > > ________________________________ Message 14 ____________________________________ Time: 03:42:59 PM PST US From: Wheeler North Subject: RV-List: air oil separator --> RV-List message posted by: Wheeler North You mention the "bilinski mod" to an ACS air/oil separator. try http://www.aircraftspruce.com/catalog/eppages/hboilbreather.php cut 2.5" hole in front or back face, fill with Stainless Steel Pot scrubbers(do not use any plastic or corrodeable wools). http://sneakykitchen.com/fullerbrush/fuller_products/kitchen.htm or http://products3.3m.com/catalog/us/en001/food_beverage/food_service/node_GSX 8YGLK7Pgs/root_GST1T4S9TCgv/vroot_GS56SL819Pge/bgel_GSNMFHCK49bl/gvel_GS2JDJ L946gl/theme_us_foodservices_3_0/command_AbcPageHandler/output_html repatch link Use fine mesh SS screen on bottom oil return outlet. Proseal back together, pop rivet as needed, read previous post about outlet and inlet tube lengths and position. If you get one without some overlap I'd send it back. So far no drops of oil on ground or belly or the airplane's belly. And I been chasing a lot of upside down white puffy hazy areas the last few days. W PS, this also means I no longer have to wash my belly with avgas, that's a relief... my armpits were really gettin' scratchy and dry. ________________________________ Message 15 ____________________________________ Time: 03:42:59 PM PST US From: "lyle" Subject: RV-List: Stick grips --> RV-List message posted by: "lyle" Listers, Anybody know of a supplier of nice wooden grips that Van used to sell ? The current crop are very $$$, but there used to be a good source of nice grips at a reasonable price. Thanks, Lyle ________________________________ Message 16 ____________________________________ Time: 04:21:03 PM PST US From: "William Davis" Subject: RV-List: RV-8 Canopy Latch --> RV-List message posted by: "William Davis" RV-8 Builders, I still have some Rv-8 Canopy Latches available. For a write up with pictures go to: http://home.hiwaay.net/~sbuc/journal/rv8-latch.html Best regards, Bill Davis ________________________________ Message 17 ____________________________________ Time: 04:33:13 PM PST US From: Kevin Horton Subject: Re: RV-List: Re: RV-List Digest: 35 Msgs - 12/03/04 --> RV-List message posted by: Kevin Horton >--> RV-List message posted by: Mlfred@aol.com > > >In a message dated 12/4/2004 4:14:26 AM Central Standard Time, >rv-list-digest@matronics.com writes: > >The basic point remains, you need more power to maintain the same CAS at a >higher altitude. > >Jim Oke >Wpg., MB > > >I beg your pardon if I show my ignorance here. > >2100RPM/23"MP = 9.5GPH (most of the time --varies slightly with temps), and >this shows about 165KIAS on the ASI in my F1 (not calibrated by any means). >This seems to be the case at 2000'MSL or 8000'MSL. I do see a >difference in GS >(increases with altitude), if the wind factor is removed. > >This seems to refute the 'takes more power at altitude' argument: I get an >increase in GS with no increase in fuel flow...and I have always thought fuel >flow in GPH x ~14 = HP when operating LOP for the 8.5 comp engines. > >Now, in looking at the P&W R985 power charts, it shows a lower MP (and fuel >flow) at higher altitudes to get the same power -- I recall this is due to >the lower ambient pressure in the crankcase..along with the lower >ambient pres >seen by the exhaust system. > >So, it would seem that the power chart tells us that it takes a lower fuel >flow to get the same power at a higher altitude...so, if the flow remains >constant, you would be seeing a power increase? > >It's getting a bit nebulous now... 'splain it to me (again), Lucy. What I >have seen in 6000hrs of flying tells me higher = faster = cheaper, >at least on >longer trips where the extra fuel for the climb can be eliminated by the >greater efficiency of flight at a higher altitude. > >It may be that flying higher in a turbo- or supercharged engine starts to >allow the blower to use some percentage of the produced HP to >operate the blower > itself -- could this be the source of the higher power required to fly at >the same CAS at 22,000MSL? I recall the automotive blower folks >telling me that >a blown engine uses more fuel per HP when under boost...but the efficiency >charts for the big round motors doesn't show that same drop off... > >So, help me understand this, one more time... > >Cheers >Mark Mark, What engine do you have? Some sort of 260 hp O-540, if I recall correctly. What mods does it have? If you take a close look at the published power charts for piston engines, you will note that the power output for a given rpm and MP increases with altitude. I don't completely understand the reasons, but it is at least partially due to the fact that the lower exhaust back pressure helps the engine breath better. Looking at the power chart for an O-360, I see that 2100 and 23" is about 65% power at 2,000 ft, and about 72% power at 8,000 ft, assuming standard temperatures. I would expect that the percent power for an O-540 would vary similarly with altitude. The true airspeed for a given aircraft should be proportional to the cube root of (power divided by air density), assuming the weight and prop efficiency are unchanged. 165 KCAS at 2,000 ft is about 170 KTAS. The density ratio at 2,000 ft is 0.943 and at 8,000 ft it is 0.786 (density ratio is the air density at this condition divided by the air density at sea level, standard day conditions). So, if your aircraft does 179 KTAS on 66% power at 2,000 ft, it should do about 170 X the cube root of (.72/65 X .943/.786) = 187 KTAS, which is 166 KCAS. So, your observations are consistent with what I would expect. If you can find a power chart for your engine, figure out some rpm and MP combinations so you can test with the same power at 2,000 and 8,000 ft, then you should find that you get a lower CAS at the higher altitude. -- Kevin Horton RV-8 (finishing kit) Ottawa, Canada http://go.phpwebhosting.com/~khorton/rv8/ ________________________________ Message 18 ____________________________________ Time: 04:47:53 PM PST US From: Hopperdhh@aol.com Subject: Re: [Bulk] RV-List: Rv-List Power Required --> RV-List message posted by: Hopperdhh@aol.com One reason that engines are more efficient at higher altitude that I haven't seen listed here has to do with pumping loss. Pumping loss is fundamental to how piston engines operate, and is one reason why diesel engines are more efficient than gasoline engines. The diesel has no throttle plate, so it has no (or actually very little) pumping loss. The same applies when you are able to operate your aircraft engine at higher altitude. When you open the throttle all the way the pumping loss (nearly) disappears. This is also one of the reasons that a car that is geared higher (lower RPM) is more efficient that one with a lower gear ratio. With the lower gear ratio, a lot of the power the engine makes gets wasted sucking on that nearly closed throttle. (Please don't give me a lecture on pressure vs. suction!) There are other reasons that have already been stated here, but I'm only trying to make the point that low pumping loss is one contributor to high altitude efficiency. Dan Hopper N766DH RV-7A (Flying since July -- about 80 hours now) ________________________________ Message 19 ____________________________________ Time: 05:15:17 PM PST US From: "Alex Peterson" Subject: RE: [Bulk] RV-List: Rv-List Power Required --> RV-List message posted by: "Alex Peterson" > I was on the road without e-mail access since early in this thread. > It looks like Ed's questions have been pretty much answered, I think. > > One comment on your plan Alex - if you want the same power at > different altitudes, the MP will be a bit lower at the higher > altitude. Kevin, is this because of lower pumping losses at higher altitudes? (throttle not inducing as much inefficiency is another way of stating this) Alex Peterson RV6-A 558 hours Maple Grove, MN http://www.home.earthlink.net/~alexpeterson/ ________________________________ Message 20 ____________________________________ Time: 05:53:47 PM PST US From: "Dan Checkoway" Subject: Re: RV-List: Stick grips --> RV-List message posted by: "Dan Checkoway" http://www.rvproject.com/20030605.html has some info on the teak grips that Michael makes. Good stuff, feels good to the touch, functional, yadda yadda. ;-) )_( Dan RV-7 N714D http://www.rvproject.com ----- Original Message ----- From: "lyle" Subject: RV-List: Stick grips > --> RV-List message posted by: "lyle" > > Listers, > Anybody know of a supplier of nice wooden grips that Van used to sell ? > The current crop are very $$$, but there used to be a good source of nice grips at a reasonable price. > > Thanks, > Lyle > > ________________________________ Message 21 ____________________________________ Time: 06:16:35 PM PST US From: Kevin Horton Subject: RE: [Bulk] RV-List: Rv-List Power Required --> RV-List message posted by: Kevin Horton >--> RV-List message posted by: "Alex Peterson" > > >> I was on the road without e-mail access since early in this thread. >> It looks like Ed's questions have been pretty much answered, I think. >> >> One comment on your plan Alex - if you want the same power at >> different altitudes, the MP will be a bit lower at the higher >> altitude. > >Kevin, is this because of lower pumping losses at higher altitudes? >(throttle not inducing as much inefficiency is another way of stating this) > Alex, I don't claim to completely understand why piston engines make more power at altitude for the same rpm and MP, but I've seen this on every power chart or power table that I've studied. Lower pumping losses and lower exhaust back pressure are both part of the reason, but I don't know the relative contributions of these two items, nor do I know what other factors might be involved. -- Kevin Horton RV-8 (finishing kit) Ottawa, Canada http://go.phpwebhosting.com/~khorton/rv8/ ________________________________ Message 22 ____________________________________ Time: 06:17:14 PM PST US From: "Jack Ford" Subject: Re: [Bulk] RV-List: Rv-List Power Required --> RV-List message posted by: "Jack Ford" Another consideration relating to pumping losses is exhaust back pressure. There is less atmospheric resistance to the exhaust exiting at high altitude. Jack Ford ----- Original Message ----- From: Subject: Re: [Bulk] RV-List: Rv-List Power Required > --> RV-List message posted by: Hopperdhh@aol.com > > > One reason that engines are more efficient at higher altitude that I haven't > seen listed here has to do with pumping loss. Pumping loss is fundamental to > how piston engines operate, and is one reason why diesel engines are more > efficient than gasoline engines. The diesel has no throttle plate, so it has no > (or actually very little) pumping loss. The same applies when you are able to > operate your aircraft engine at higher altitude. When you open the throttle > all the way the pumping loss (nearly) disappears. This is also one of the > reasons that a car that is geared higher (lower RPM) is more efficient that one > with a lower gear ratio. With the lower gear ratio, a lot of the power the > engine makes gets wasted sucking on that nearly closed throttle. (Please don't > give me a lecture on pressure vs. suction!) There are other reasons that have > already been stated here, but I'm only trying to make the point that low > pumping loss is one contributor to high altitude efficiency. > > Dan Hopper > N766DH > RV-7A (Flying since July -- about 80 hours now) > > ________________________________ Message 23 ____________________________________ Time: 06:19:53 PM PST US From: Bobby Hester Subject: Re: RV-List: Stick grips --> RV-List message posted by: Bobby Hester lyle wrote: >--> RV-List message posted by: "lyle" > >Listers, > Anybody know of a supplier of nice wooden grips that Van used to sell ? > The current crop are very $$$, but there used to be a good source of nice grips at a reasonable price. > >Thanks, >Lyle > > > Vans still sells them, I just bought two! -- Surfing the Web from Hopkinsville, KY Visit my web site at: http://www.geocities.com/hester-hoptown/RVSite/ RV7A Slowbuild wings-QB Fuse :-) ________________________________ Message 24 ____________________________________ Time: 07:48:27 PM PST US From: richard dudley Subject: Re: RV-List: air oil separator --> RV-List message posted by: richard dudley Thanks Wheeler ane Mark for your responses. Sure sounds good for $38 and a litttle modification. I also like the sounds of your results. Regards, Richard Dudley Wheeler North wrote: >--> RV-List message posted by: Wheeler North > >You mention the "bilinski mod" to an ACS air/oil separator. > > >try http://www.aircraftspruce.com/catalog/eppages/hboilbreather.php > >cut 2.5" hole in front or back face, fill with Stainless Steel Pot >scrubbers(do not use any plastic or corrodeable wools). > >http://sneakykitchen.com/fullerbrush/fuller_products/kitchen.htm >or >http://products3.3m.com/catalog/us/en001/food_beverage/food_service/node_GSX >8YGLK7Pgs/root_GST1T4S9TCgv/vroot_GS56SL819Pge/bgel_GSNMFHCK49bl/gvel_GS2JDJ >L946gl/theme_us_foodservices_3_0/command_AbcPageHandler/output_html > >repatch link > >Use fine mesh SS screen on bottom oil return outlet. > >Proseal back together, pop rivet as needed, read previous post about outlet >and inlet tube lengths and position. If you get one without some overlap I'd >send it back. > >So far no drops of oil on ground or belly or the airplane's belly. And I >been chasing a lot of upside down white puffy hazy areas the last few days. > >W > >PS, this also means I no longer have to wash my belly with avgas, that's a >relief... my armpits were really gettin' scratchy and dry. > > > > ________________________________ Message 25 ____________________________________ Time: 08:15:31 PM PST US From: "Dan Checkoway" Subject: Re: RV-List: air oil separator --> RV-List message posted by: "Dan Checkoway" I like this idea but wonder if it's something that requires periodic maintenance. Specifically the pot scrubber and the mesh over the return port. If they got clogged or sludged up it could become problematic. For example, even with the cleanest oil changed frequently, I imagine the pot scrubber will sludge up a bit over time. And if the steel mesh on the return port were blocked, the cannister would essentially just fill up with sludge. Worst case, it would be a shame if the air/oil separator became essentially blocked and caused a crank seal blowout. I do like the idea, though. I think patching the hole with a plate that is removable (with screws & nutplates) would be a good approach. Every year at annual condition inspection time you open it up, remove the scrubber, soak/clean it, clean the inside of the cannister, etc. Something like that. I guess the only question would be whether to use the cork gasket, or just proseal (kidding!). ;-) )_( Dan RV-7 N714D http://www.rvproject.com ----- Original Message ----- From: "Wheeler North" Subject: RV-List: air oil separator > --> RV-List message posted by: Wheeler North > > You mention the "bilinski mod" to an ACS air/oil separator. > > > try http://www.aircraftspruce.com/catalog/eppages/hboilbreather.php > > cut 2.5" hole in front or back face, fill with Stainless Steel Pot > scrubbers(do not use any plastic or corrodeable wools). > > http://sneakykitchen.com/fullerbrush/fuller_products/kitchen.htm > or > http://products3.3m.com/catalog/us/en001/food_beverage/food_service/node_GSX > 8YGLK7Pgs/root_GST1T4S9TCgv/vroot_GS56SL819Pge/bgel_GSNMFHCK49bl/gvel_GS2JDJ > L946gl/theme_us_foodservices_3_0/command_AbcPageHandler/output_html > > repatch link > > Use fine mesh SS screen on bottom oil return outlet. > > Proseal back together, pop rivet as needed, read previous post about outlet > and inlet tube lengths and position. If you get one without some overlap I'd > send it back. > > So far no drops of oil on ground or belly or the airplane's belly. And I > been chasing a lot of upside down white puffy hazy areas the last few days. > > W > > PS, this also means I no longer have to wash my belly with avgas, that's a > relief... my armpits were really gettin' scratchy and dry. > >