Return-Path: Sender: (Marvin Kaye) To: lml Date: Mon, 14 Apr 2003 00:38:01 -0400 Message-ID: X-Original-Return-Path: Received: from [32.97.166.32] (HELO prserv.net) by logan.com (CommuniGate Pro SMTP 4.1b3) with ESMTP id 2121520 for lml@lancaironline.net; Sun, 13 Apr 2003 21:32:32 -0400 Received: from b8p5r1 (slip-12-65-210-139.mis.prserv.net[12.65.210.139]) by prserv.net (out2) with SMTP id <2003041401320320202jc098e>; Mon, 14 Apr 2003 01:32:04 +0000 From: "Larry Henney" X-Original-To: "'Jean-Pierre van der Burgt'" , "Lorn H. Olsen" , "Lancair List" Subject: LNC2 speed "trick" X-Original-Date: Sun, 13 Apr 2003 20:32:06 -0500 X-Original-Message-ID: <000001c30225$aa61fda0$8bd2410c@b8p5r1> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C301FB.C18BF5A0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.2627 Importance: Normal In-Reply-To: <017e01c2fd4e$a2b7dbf0$a85076d5@exskdzkx5j0yq52> X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2919.6600 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C301FB.C18BF5A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Jean-Pierre, Lorn, and LNC2 friends, In an effort to level the playing field and make LNC2 racing more interesting I thought it prudent to provide the following discussion to the List. Stated another way I'm tired of whipping you all so badly that you refuse to come to the races so pay attention and improve your planes. In response to your speed queries I thought I'd list a few of those items that may contribute to my airplanes solid performance. It should be noted that cheating is of course paramount. And therefore I would ask that you gentleman be judicious in your generosity to share these tips. Also, be careful to not kill yourself or anyone else while considering any of these tweaks. I would prefer none of you earn Darwin Awards after seeking another 1/4 kt. A noteworthy truth is that I've never seen above 213 kts steady state ground speed on my GPS with upwind and downwind averaged legs. During the Sun 100 I saw 214 kts for a while but mostly never looked down. It is also true that whatever my speed I've not been beaten ever (Normally aspirated LNC2) in 6 consecutive races. This may of course be partly because minimal people come to races :( In particular Scott Krueger's analysis of turn radii from the book Aerodynamics for Naval Aviators applies to the Sun 100. The GPS distance for the Sun 100 is 76 NM. Scott's calculation to add about 6 NM for 360 deg of turn radius is a reasonable thought. I believe he based this on a 30 deg bank angle. I imagine it would be legitimate to add another 2 miles for runway length. That is, the takeoff southbound turn is not permitted before exiting airport property (One runway length). Additionally, the arrival turn from south to east adds about 1 full runway length because we were precluded from overflying a camping area on the south west corner of the airport. Anyway, my total time was 22:35. Backing this number out of 217.86 Kts yields a race course length of 82 Nm. These are just things to think about. In reference to cheating I would never turn during a race with less than FAA aerobatic bank angle limitations. I was dead on top of the turn points and pulled solid G to get around them. Indeed it would be fair to say that I cut one gentleman off in the turn. He was however over 1 mile past the point when I arrived (that'd be about 20 seconds). I thought it safe to assume he was just out joy riding. Scott's Hi Yo Yo discussion probably holds little to be gained with the speeds we're considering. (FWIW) In a fighter jet if one wanted to decelerate to "corner airspeed" then such a climbing manuever might provide some benefit and compensate for excess bleed rates. IMHO this airplane has minimal bleed when cornering. With all that being said, the other disclaimer I have is that my plane is pretty much as built, (then crashed and rebuilt). Thus, I have no idea which tweaks actually cause the slight advantage I'm seeing over the competition. I also have about zero insight into the engineering value of individual mods as I was too busy building to do much studying when I built my plane. I heard, "that'll make it faster" and I did it. Alot of what I heard came from an EAA meeting with Dave Anders. He had just won the CAFE competition with his RV 4 and provided numerous tips. I didn't bother with how much faster each mod would be, I just did them all. I will however list my uniquenesses in order of my best speed value guestimation. 1) I turn the Hartzell 68" prop at 2920 RPM. This results in 30.7 in MAP flying at sea level. Don't do this without some convincing that your prop and crank can be turned this fast safely. My understanding of a Hartzell certified prop is that they are designed to handle 150% of rated max rpm (2700 x 1.5 = 4000). Mach analysis and temperature dependance above this rpm is mandatory. Don't just stay under Mach 1.0. You must be under that rpm where dramatic drag rise from mach affects ensues. Don't break anything up here or death will be shortly thereafter. 2) Dual LSE electronic ignition. Buy'm from Klaus Savier and tell him I sent ya. I get no royalties just enjoy heckling and beating him with his own equipment. Didn't ever use mags so can't prove how great they are but sure enjoy the fuel savings to and from the races. 3) 9:1 pistons in the Injected 180 HP engine (I'm told they make it an empirical 192HP). Engine was polished, ported, mass balanced, dynamically balanced, then crash tested with a gear up takeoff. You may not find any extra benefit from the latter. I have an updraft sump. The injector servo faces forward with about 4" between the servo and the air intake ring. The required 90 deg turn is a bolted on 90 deg elbow (not pretty). The forward facing sump argument has me beat by excess cost but also may not provide the total intended claimed benefits because of internal aerodynamic uglies depending on your sump modifications. 4) I have aY valve crammed in between the servo and the ram air intake. Atop this valve sits a K&N air filter. Since the flapper only closes the ram side of the valve it deters performance when RAM is selected. That is, the higher pressure ram air back flows out the filter when it should be going into the sump. Therefore, when racing I remove the filter entirely and plug that side of the Y valve. The filter/ram lever is of course safety wired to minimize stupid pilot activities (which I've occasionally been party to). 5) Aerodynamically, as you suggest (Jean-Pierre) the plane is almost flawless dragwise. My inboard gear doors may hang down about 1/8" and my two trim motor drive linkages are not faired. I've recently adjusted my right elevator up about .025" to better center it between horizontal stab skins. All else is very smooth. My horizontal tail incidence was intended to be less negative than spec'd (I believe 1/2 deg nose down was the design parameter). In the end the water level as compared to the smart level were at both ends of the factory recommended incidence tolerance. (+/- 1/4 deg maybe?) Elevator trim does indeed sit at zero while at 212 KTs but this does not alone convince me that my elevators are perfectly level to the horizontal tail. 6) My pressure cowl has Lo Presti style air cooling intakes which feed into a fiberglass plenum. The rings (off the shelf from Sam James of RV land) are the perfect size. It is apparently of value to match the ring internal airfoil to the external airfoil along the cowl. They sit about 1/2" back from the prop. I sit on 180 - 200 deg C on CHT's with oil temp while racing at 95-100 deg C. (These CHT numbers are the top of the green arc for you farenheit fans, oil in the yellow range but much cooler than many of my competitors) I have no additional NACA scoops or air cooling on the cowl (except engine feed air). My suspicion is many kts are lost with all the wild NACA mods and fins that we see on so many LNC2s. 7) The air entering my pressure plenum is supposed to expand at less than a 5 deg rake angle. The plenum is now sealed with Red RTV. Cooling air is borrowed into an up front oil cooler (in front of #2 cyl.). All other air is for cylinder cooling. I have no little cooling tubes for such things as alternator, starter, vacuum pump (don't have it), mags (don't have any), or the gascolator. These items haven't yet burned up (360 hours TT) perhaps due in part to #8 below. 8) The air off the cooling fins is guided with a very large piece of thin AL from the cooling fins down and aft on a gentle curve to the exit. This air has minimal tendency for eddy currents. It also performs some degree of heat shielding for the gascolator. The sheet (actually 3 pieces) makes cowling contact down the sides with 1/8" vacuum tubing to minimize abrasion. It is ugly and was a total pain to build but perhaps helpful. 9) I have recently replaced my two down turned exhaust pipe tips with straight tips (about $20 in carbon steel). The intent of this project was to slowly neck down the tips and provide either increased back pressure (MAP & Power) or a better exhaust velocity match to the surrounding air flow. Of the 4 insert rings which reduced the exhaust pipe exit area all four reduced speed. This was the only half way accurate test I've done and I'm certain it's a bad idea for my plane. The rest of my stainless exhaust was ceramic coated and I'm now using a piece of Zetex near my one hot spot/ blister (seems great!). BTW, the straight pipes are a belly soot fest! Can't stand'm for daily flying. 10) The empty weight of the plane is 1161 lb. I flew Sun 100 with my 85 lb son. I weigh 213 lbs. (get your speed over your weight then your going places). I carried 16 gal of fuel and shut down with about 7. (At least 3 gallons extra fuel including holding on the Lake Parker arrival). All that said I don't think 100 lbs affects us 1/4 kt. CG on the other hand may have an affect. Dont' kill yourself finding out. 11) I run at 17 gph +/-. This is slightly up from previous races and may be noteworthy compared to other slower speed races. I've run at 16 gph in several races (also a little higher msl altitudes). It may be a push. However, the air was very cool ( < 70 F) and super still on this particular race day. 12) While building I was friends with a 235 gentleman (Dave Roach-Great guy/ highest LNC2 houred plane that I know of). After following much list discussion of late I'm now convinced that I wrongly built my flaps with double available reflex. That is, people say that flaps faired to the fuselage fillets is -7 deg. on the newer LNC2's. I don't remember reading it this anywhere. I have about 1" above faired available for me. This builder mistake may give a smidgen of speed but I don't see any IAS difference while playing with it. I do however blow the fuse when I drop too much flap too fast. Duh! 13) Along those lines, I've not intentionally done this but my ailerons seem to sit about 1/8" above the faired wingtip. Don't play games here for a stalled aileron could also take one's life in short order. 14) I race with my alternator off to conserve engine drag (about 5 amp reduction). My 18 amp battery does fine for the short races. I turn on the alternator at 12 Volts to recharge. I also have a "Sweet Jesus" 3 amp back up battery that I don't touch except in emergency and throw away every couple years. In longer races I turn on the alternator while transferring fuel and to confirm the gear haven't drooped. Occasionally, I get a chirp from the hyd. pump when I turn on the alternator. In the Copperstate Dash, I saw a 3 kt acceleration after the chirp. Know however, that this practice provides no visible indication of a change in IAS. It just feels like it should help. Another feel good consideration might be an electric primary fuel pump (throw out the mechanical). My electrical system has a 3 tiered fault system along the Bob Knuckolls philosophy and yours should be carefully analysed before anything so outrageous is considered. 15) More feel good items ( or not actually feel good to be precise). I close the intake Naca cockpit vents. I also have two exit air holes in my aft baggage area that permit ventilation air to go down and out my tail. I plug these holes for racing. There is still gear door leaks available if you really want to go crazy. To add to the overheating pleasure I am careful to increase visibility while racing by tucking my Koger canopy shade up and out of the way. Racing is all about safe visibility. This part is painful and perhaps helpful. That's it! In the words of Forest Gump, "That's all I know about that". What do you suggest I tweak next? Larry Henney N360LH Union votes tomorrow to decide whether I'll have to sell her or not (possible bummer ahead). ------=_NextPart_000_0001_01C301FB.C18BF5A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
Jean-Pierre, = Lorn, and LNC2=20 friends,
 
In an effort=20 to level the playing field and make LNC2 racing more interesting I = thought it=20 prudent to provide the following discussion to the List.  Stated = another=20 way I'm tired of whipping you all so badly that you refuse to come to = the races=20 so pay attention and improve your planes.
 
In response to=20 your speed queries I thought I'd list a few of those items that may = contribute=20 to my airplanes solid performance.  It should be noted that = cheating is of=20 course paramount.  And therefore I would ask that you gentleman be=20 judicious in your generosity to share these tips.  Also, be careful = to not=20 kill yourself or anyone else while considering any of these = tweaks.  I=20 would prefer none of you earn Darwin Awards after seeking another 1/4 = kt. =20 A noteworthy truth is that I've never seen above 213 kts steady state = ground=20 speed on my GPS with upwind and downwind averaged legs.  During the = Sun 100=20 I saw 214 kts for a while but mostly never looked down.  It is also = true=20 that whatever my speed  I've not been beaten ever=20 (Normally aspirated LNC2) in 6 consecutive races.  This may of = course be=20 partly because minimal people come to races = :(
 
In particular=20 Scott Krueger's analysis of turn radii from the book Aerodynamics for = Naval=20 Aviators applies to the Sun 100.  The GPS distance for the Sun 100 = is 76=20 NM.  Scott's calculation to add about 6 NM for 360 deg of turn = radius=20 is a reasonable thought.  I believe he based this on a 30 deg bank=20 angle.  I imagine it would be legitimate to add another 2 = miles=20 for runway length.  That is, the takeoff southbound turn is not = permitted=20 before exiting airport property (One runway length).  Additionally, = the=20 arrival turn from south to east adds about 1 full runway length = because we=20 were precluded from overflying a camping  area on the south west = corner of=20 the airport.  Anyway, my total time was 22:35.  Backing this = number=20 out of 217.86 Kts yields a race course length of 82 Nm.  These are = just=20 things to think about. 
 
In reference=20 to cheating I would never turn during a race with less than FAA = aerobatic bank=20 angle limitations.  I was dead on top of the turn points and pulled = solid G=20 to get around them.  Indeed it would be fair to say that I = cut one=20 gentleman off in the turn.  He was however over 1 mile past the = point when=20 I arrived (that'd be about 20 seconds).  I thought it safe to = assume he was=20 just out joy riding.  Scott's Hi Yo Yo discussion probably holds = little to=20 be gained with the speeds we're considering.   (FWIW) In a = fighter jet=20 if one wanted to decelerate to "corner airspeed" then such a climbing = manuever=20 might provide some benefit and compensate for excess bleed rates.  = IMHO=20 this airplane has minimal bleed when = cornering.
 
With all that=20 being said, the other disclaimer I have is that my plane is pretty much = as=20 built, (then crashed and rebuilt).  Thus, I have no idea which = tweaks=20 actually cause the slight advantage I'm seeing over the = competition.  I=20 also have about zero insight into the engineering value of individual = mods as I=20 was too busy building to do much studying when I built my plane.  I = heard,=20 "that'll make it faster" and I did it.  Alot of what I heard came = from an=20 EAA meeting with Dave Anders.  He had just won the CAFE = competition=20 with his RV 4 and provided numerous tips.  I didn't bother with how = much=20 faster each mod would be, I just did them all.  I will however = list my=20 uniquenesses in order of my best speed value=20 guestimation.
 
1)      I turn the = Hartzell=20 68" prop at 2920 RPM.  This results in 30.7 in MAP flying at sea=20 level.  Don't do this without some convincing that your prop and = crank can=20 be turned this fast safely.  My understanding of a Hartzell = certified prop=20 is that they are designed to handle 150% of rated max rpm (2700 x 1.5 = =3D=20 4000).  Mach analysis and temperature dependance above this rpm is=20 mandatory.  Don't just stay under Mach 1.0.  You must be under = that=20 rpm where dramatic drag rise from mach affects ensues.  Don't break = anything up here or death will be shortly = thereafter.
 
2)      Dual LSE = electronic=20 ignition.  Buy'm from Klaus Savier and tell him I sent ya.  I = get no=20 royalties just enjoy heckling and beating him with his own = equipment. =20 Didn't ever use mags so can't prove how great they are but sure enjoy = the fuel=20 savings to and from the races.
 
3)    9:1 pistons in the = Injected 180 HP=20 engine (I'm told they make it an empirical 192HP).  Engine was = polished,=20 ported, mass balanced, dynamically balanced, then crash tested with a = gear up=20 takeoff.  You may not find any extra benefit from the = latter.  I=20 have an updraft sump.  The injector servo faces forward with about=20 4" between the servo and the air intake ring.  The = required 90=20 deg turn is a bolted on 90 deg elbow (not pretty).  The forward = facing sump=20 argument has me beat by excess cost but also may not provide the total = intended=20 claimed benefits because of internal aerodynamic uglies depending on = your sump=20 modifications.
 
4)    I have aY valve crammed = in between=20 the servo and the ram air intake.  Atop this valve sits a K&N = air=20 filter.  Since the flapper only closes the ram side of the valve it = deters=20 performance when RAM is selected.  That is, the higher pressure ram = air=20 back flows out the filter when it should be going into the sump. = Therefore, when=20 racing I remove the filter entirely and plug that side of the Y = valve.  The=20 filter/ram lever is of course safety wired to minimize stupid pilot = activities=20 (which I've occasionally been party to).
 
5)    Aerodynamically, as you = suggest=20 (Jean-Pierre) the plane is almost flawless dragwise.  My inboard = gear doors=20 may hang down about 1/8" and my two trim motor drive linkages are not=20 faired.  I've recently adjusted my right elevator up about .025" to = better=20 center it between horizontal stab skins.  All else is very = smooth.  My=20 horizontal tail incidence was intended to be less negative than spec'd = (I=20 believe 1/2 deg nose down was the design parameter).  In the end = the water=20 level as compared to the smart level were at both ends of the factory=20 recommended incidence tolerance. (+/- 1/4 deg maybe?)  Elevator = trim does=20 indeed sit at zero while at 212 KTs but this does not alone convince me = that my=20 elevators are perfectly level to the horizontal=20 tail.
 
6)  My=20 pressure cowl has Lo Presti style air cooling intakes which feed into a=20 fiberglass plenum.  The rings (off the shelf from Sam James of RV = land) are=20 the perfect size.  It is apparently of value to match the ring = internal airfoil to the external airfoil along the cowl.  They sit = about=20 1/2" back from the prop.   I sit on 180 - 200 deg C on CHT's = with oil=20 temp while racing at 95-100 deg C.  (These CHT numbers are the top = of the=20 green arc for you farenheit fans, oil in the yellow range but much = cooler than=20 many of my competitors)  I have no additional NACA scoops or air = cooling on=20 the cowl (except engine feed air).  My suspicion is many kts are = lost with=20 all the wild NACA mods and fins that we see on so many=20 LNC2s.
 
7)  The=20 air entering my pressure plenum is supposed to expand at less than a 5 = deg rake=20 angle.  The plenum is now sealed with Red RTV.  Cooling air is = borrowed into an up front oil cooler (in front of #2 cyl.).  All = other air=20 is for cylinder cooling.  I have no little cooling tubes for such = things as=20 alternator, starter, vacuum pump (don't have it), mags (don't have = any), =20 or the gascolator.  These items haven't yet burned up (360 hours = TT)=20 perhaps due in part to #8 below.
 
8)    The air off the cooling = fins is=20 guided with a very large piece of thin AL from the cooling fins down and = aft on=20 a gentle curve to the exit.  This air has minimal tendency for eddy = currents.  It also performs some degree of heat shielding for the=20 gascolator.  The sheet (actually 3 pieces) makes cowling contact = down the=20 sides with 1/8" vacuum tubing to minimize abrasion.  It is ugly and = was a=20 total pain to build but perhaps helpful.
 
9)    I have recently replaced = my two=20 down turned exhaust pipe tips with straight tips (about $20 in carbon=20 steel).  The intent of this project was to slowly neck down the = tips and=20 provide either increased back pressure (MAP & Power) or a better = exhaust=20 velocity match to the surrounding air flow.  Of the 4 insert rings = which=20 reduced the exhaust pipe exit area all four reduced speed.  This = was the=20 only half way accurate test I've done and I'm certain it's a bad idea = for my=20 plane.  The rest of my stainless exhaust was ceramic coated and I'm = now=20 using a piece of Zetex near my one hot spot/ blister (seems = great!).  BTW,=20 the straight pipes are a belly soot fest!  Can't stand'm for daily=20 flying.
 
10)  The=20 empty weight of the plane is 1161 lb.  I flew Sun 100 with my 85 lb = son.  I weigh 213 lbs.  (get your speed over your weight then = your=20 going places).  I carried 16 gal of fuel and shut down with about = 7. =20 (At least 3 gallons extra fuel including holding on the Lake Parker=20 arrival).  All that said I don't think 100 lbs affects us 1/4 = kt.  CG=20 on the other hand may have an affect.  Dont' kill yourself finding=20 out.
 
11)    I run at 17 gph = +/-.  This=20 is slightly up from previous races and may be noteworthy compared to = other=20 slower speed races.  I've run at 16 gph in several races (also a = little=20 higher msl altitudes). It may be a push.  However, the air was very = cool (=20 < 70 F) and super still on this particular race=20 day.
 
12)     While building I = was=20 friends with a 235 gentleman (Dave Roach-Great guy/ highest LNC2 houred = plane=20 that I know of).  After following much list discussion of late I'm = now=20 convinced that I wrongly built my flaps with double available = reflex.  That=20 is, people say that flaps faired to the fuselage fillets is -7 deg. = on the=20 newer LNC2's.  I don't remember reading it this = anywhere.  =20 I have about 1" above faired available for me.  This builder = mistake may=20 give a smidgen of speed but I don't see any IAS difference while playing = with=20 it.  I do however blow the fuse when I drop too much flap too = fast. =20 Duh!
 
13)      Along those = lines,=20 I've not intentionally done this but my ailerons seem to sit about = 1/8"=20 above the faired wingtip.  Don't play games here for a stalled = aileron=20 could also take one's life in short order.
 
14)    I race with my = alternator off to=20 conserve engine drag (about 5 amp reduction).  My 18 amp battery = does fine=20 for the short races.  I turn on the alternator at 12 Volts to=20 recharge.  I also have a "Sweet Jesus" 3 amp back up battery that I = don't=20 touch except in emergency and throw away every couple years.  In = longer=20 races I turn on the alternator while transferring fuel and to = confirm=20 the gear haven't drooped.  Occasionally, I get a chirp from the = hyd. pump=20 when I turn on the alternator. In the Copperstate Dash, I saw a 3 kt=20 acceleration after the chirp.  Know however, that this practice = provides no=20 visible indication of a change in IAS.  It just feels like it = should=20 help.  Another feel good consideration might be an electric primary = fuel=20 pump (throw out the mechanical).  My electrical system has = a 3=20 tiered fault system along the Bob Knuckolls philosophy and yours should = be=20 carefully analysed before anything so outrageous is=20 considered.
 
15) More feel=20 good items ( or not actually feel good to be = precise).  I=20 close the intake Naca cockpit vents.  I also have two exit air = holes in my=20 aft baggage area that permit ventilation air to go down and out my = tail.  I=20 plug these holes for racing.  There is still gear door = leaks=20 available if you really want to go crazy.  To add to the = overheating=20 pleasure I am careful to increase visibility while racing by tucking my = Koger=20 canopy shade up and out of the way.  Racing is all about safe=20 visibility.  This part is painful and perhaps=20 helpful.
 
That's=20 it!  In the words of Forest Gump, "That's all I know about=20 that".   What do you suggest I tweak = next?
 
Larry=20 Henney
N360LH
 
Union votes=20 tomorrow to decide whether I'll have to sell her or not (possible bummer = ahead).
 
 
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