Testing

<body topmargin=0 leftmargin=0 marginheight=0 marginwidth=0> <table cellpadding=0 cellspacing=0 border=0><tr> <td valign="top" colspan=2 height=100 BGCOLOR="#CCCCFF" TEXT="#080000" bgproperties="fixed" background="05b00640egdysm.jpg"> <div> <FONT SIZE="2" COLOR="#000066" FACE="Arial" ><B>Steve Kiblinger, .. Builder of a Milholland Better Half 2 cylinder VW and Legal Eagle Ultralight Airplane</B></FONT><B> </B><B>    |   </B><A HREF="index.htm" TARGET="_top" TITLE="Steve Kiblinger, .. Builder of a Milholl"><U><B>Home</B></U></A><B> </B><A HREF="brucesengine.htm" TARGET="_top" TITLE="BrucesEngine"><U><B>BrucesEngine</B></U></A></div> <div>                                                   </div> <div> </div> </td> </tr><tr> <td valign="top" width=200 BGCOLOR="#0000BF" TEXT="#F7F7FF"> <bR> </td> <td valign="top" height=380 BGCOLOR="#FFFFFF" TEXT="#080000"> <div> <I>Testing</I></div> <div> <B>1) We strongly recommend that the engine be built in parallel with the airframe... A test stand should be mounted on a dual purpose trailer that will later haul the completed project to a  l o n g  clear flying area for flight testing... With a trailer mounted test stand you can take the engine to some remote place for a minimum  6 hour run-in before mounting to the airframe... Oil leaks on the test stand will not screw up your slick new fuselage/empennage... Importantly, you will not be dodging prop and fuselage to go from one side to the other adjusting carbs and just looking... Wear ear protection as the 6 hours of engine noise will send you to Belltone early... The elevated test stand (trailer) prevents eroding the leading edge of your beautiful Peery Prop... We lifted the tail on our fuselage for the first test run to level the crankcase  (optimizing initial oil pump pickup) and stoned the prop... </B></div> <bR> <div> <B>2) On the initial run your engine will not have much suction and a lot of blow-by thru the breather because the rings haven't seated... We turned the engine thru fast with the sparkplug's out to get some oil circulating... The circulation was visible in the clear oil pressure gauge line... Sparkplug's in and ignition on we flipped the prop a couple dozen times with the chokes on and nothing happened - Roman was getting tired holding the fire extinguisher... With the ignition off I removed one air cleaner and put my hand over the carb inlet to get a maximum choke while flipping the prop with the other hand... I did this until the gas ran out of the carb... Ignition back on and the throttle cracked an 1/8 the choked cylinder started barking and soon the other cylinder joined it... Initial carb adjustment was idle speed screw 1/2 turn out, idle air screw 2 turns out... The carb throttle cables (both) were adjusted with the idle speed screws totally out and then carefully screwing in the cable adjustment nut until the slide (just) starts to open visually... Be sure to securely tighten the lock nut here because you will have this assembly off many times and don't want to disrupt the cable adjustment - remember to set the idle speed screws back to 1/2 turn out... We had trouble over-powering the carb slide springs with our throttle lever and carefully cut 25% of the length off the (TOP) of these springs with a Dremel cut-off wheel and smoothed the cut end - we speculate these springs are excessively strong to overcome jumping forces impressed on motorcycles and snowmobiles... BE SURE the throttle control cable is securely anchored at each end and any open couplings!... If your throttle doesn't go from closed to wide open and back to idle easily and smoothly you are not ready to fly yet...</B></div> <bR> <div> <B>3) The engine is running!... Ideally we have proper oil pressure and move the throttle to 1800 RPM to run 20 minutes for the initial seating of the valve lifters to the camshaft... In our case we noted the oil pressure pegged at 125 lbs and shut down... We tapped the gauge and examined the line for anomalies - ran again and still 125+... Got special fittings and tested oil gauge with air compressor - tested accurate... Pulled pressure valves from both ends of engine to be sure they would fall free when the caps were removed - they did... Long spring in front and short in back (flywheel end) - yes... Tried front spring from junk engine - 125 +... Swapped valves so small simple valve is at back (flywheel end) - 60 lbs at idle, geez...</B></div> <bR> <div> <B>4) Look engine over for oil leaks... Ours leaked almost everywhere Permatex Aviation 3H was used and profusely at the valve covers... We stopped the engine many times to fix leaks and the solutions are on the </B><A HREF="id52.htm" TARGET="_top" TITLE="VwOilGallerySchematic"><U><B>VwOilGallerySchematic</B></U></A><B> page...</B></div> <bR> <div> <B>5) The rings seated at about 30 minutes of running because we use #30 non detergent oil initially and until the engine starts showing more power usually in 10 - 20 hours... We changed the oil and oil filter after the first long run to get rid of the camshaft/lifter break-in compound and any debris that might have started moving... Change the oil again if it starts to color... We will convert to Mobil 1 10-30 and 1/2 a can of AvBlend... If we were using Av fuel then AeroShell 15-50 with 1/2 a can of AvBlend... The Mobil 1 and AvBlend combined after a few hours will give us another 125 RPM from my experience plus the best heat/wear protection you can buy... Don't worry about overheating the oil on the test stand - the temp rarely gets off the minimum 100 degrees F at the low end of the scale... We found the mechanical oil temp unit sold for Quickies in the Aircraft Spruce & Specialities catalog to be sized correctly for our purposes... Eventually we need to get rid of all the mechanical stuff to save weight and use the Grand Rapids Technologies EIS for 2 strokes with the altitude and ROC option for all measurements except airspeed...</B></div> <bR> <div> <B>6) We spent 6 Hobbs hours (countless discussion and research hours) chasing the carb mixture adjustments... We tried an O2 sensor system to adjust mixture settings and really didn't get good results until the EGT system (part of the Grand Rapids Technologies EIS functions) was installed... It was a long slow process... We strongly advocate an EGT system that has a sensor in each exhaust stack for anyone running one of these engines... More on carbs at the </B><A HREF="id59.htm" TARGET="_top" TITLE="MikuniCarb"><U><B>MikuniCarb</B></U></A><B> page...</B></div> <bR> <div> <B>7) Timing the engine was incredibly simple with the Leburg Dual EI... All I had to do was set the engine at TDC and clock the timing disk to the proper one of the 6 possible prop bolt hole combinations... The Leburg's have performed flawlessly and starting is a non event... We used a dial indicator in a sparkplug hole to locate TDC and filed a mark on the prop extension flange across from the crankcase split...</B></div> <bR> <div> <B>8) Roman nagged me until I painted the prop tips white front and back... The prop becomes quite visible from the front but just a faint blur from the back - y'all be careful!... My </B><B>1 year old </B><B>Aussie dog attacked the moving prop the first time he saw me start the engine so expect absolutely anything and stay close to the kill switch...</B></div> <bR> <div> <B>9) </B><I><B>June 10, 2002 </B></I></div> <div> <B>When we began testing the engine vibrated enough to blur the carbs... </B><B>We have adjusted the motor mount bolts to bring the rubber bushings in contact with the tubes and compressed 1/8" on each side of the firewall... A careful adjustment is important for proper vibration damping - do not over tighten these bushings... We put a wide area washer between the engine case and the rubber bushings on the bottom mount bolts because the case did not give support around the full circumference of the bushing... We have installed a </B><A HREF="http://www.balancemasters.com/" TARGET="_top" TITLE="http://www.balancemasters.com/"><U><B>Sun-Tech Innovations</B></U></A><A HREF="http://www.balancemasters.com/" TARGET="_top" TITLE="http://www.balancemasters.com/"><U><B> </B></U></A><B>balancer under the prop crush plate... This addition changed the vibration enough to let the carbs work properly - they were not flowing fuel when the carb slides were more than half open... The engine vibration is modest at idle and not noticeable above 2500 RPM at this time with a ragged spot between 1200 and 2000 RPM...</B></div> <bR> <div> <B>10) These are the spec's for our engine which vary greatly from our original plan:</B></div> <bR> <div> <B>Size: 69x94cc's </B></div> <div> <B>(We do not advocate the 94cc jug - 92's are a better choice)...</B></div> <bR> <div> <B>Head: Mexican 043 Hemi'd - CNC ported - dual plugs - 60cc's </B></div> <div> <B>Stock valve springs to put minimum load on rocker arm stands...</B></div> <bR> <div> <B>Camshaft: Engle 110</B></div> <div> <B>(Your engine will idle better & slower with a stock cam)</B></div> <div> <B>This cam is ground to power a dune buggy up hills in the 3000 RPM range and has great respect for doing that job... Our engine has turned the Peery 54x24 prop to 3100 static from day 1... The engine idles at 1050 RPM with dual ignition and 950 RPM with single ignition - either speed is too fast without brakes!...</B></div> <bR> <div> <B>Compression ratio: 8 to 1 using 91 octane auto fuel (Our field elevation is 1450 feet ASL)...</B></div> <bR> <div> <B>Oil pump: after market stock capacity with oil filter - filter number Carquest 85374</B></div> <div> <B>Modern engines last because they have oil filters - if you must save this weight do it in another system...</B></div> <bR> <div> <B>Ignition: Leburg dual EI</B></div> <div> <B>This ignition (each of the dual units) comes with a tach output plus voltage and Ignition ON alarms with thresholds sufficiently high to eliminate the need for a volt meter... The second battery brings the total weight to a few ounces more than the 009 distributor setup it replaces - if you take the volt meter out they are about equal...</B></div> <bR> <div> <B>Carburetors: Mikuni VM32-282 with lever choke kit (sure would like the plungers from the motorcycle variant)</B></div> <div> <B>We have changed the 1.5 sized inlet valves to 3.0's designed for gravity feed applications... This is a SUDCO part number 002-192 Mikuni 3.0 inlet valve... The float hinge pin has to be ground off for removal to get access to the inlet valve... Replacement hinge pins are SUDCO part number 002-605 FLOAT HINGE PIN VM32...</B></div> <div> <B>We are working our way thru the calibration process at this time...</B></div> <bR> <div> <B>Propeller extension: Milholland</B></div> <div> <B>We have found the dimensioning and machining to be of excellent quality...</B></div> <bR> <div> <B>Propeller: Peery Prop 54x24 with 3M 8672 Transparent Protective Tape on the leading edge... The prop has an excellent performance rating by flyers and is extremely well crafted... </B></div> <bR> <div> <I><B>September 1, 2004</B></I></div> <bR> <div> <B>We tested a Tennessee 54x20 prop and found it would produce 190 lbs of thrust at 3350 rpm static... I flew the airplane at 510 lbs gross and the ROC was substantially improved, further the engine at 3200 rpm and 55 mph airspeed was much smoother... In a conversation with Scott Casler at Copperstate in October, 2004 he confirmed the 1/2 Vw engine cruises better between 3200 - 3600 rpm... We had been cruising at 3050 rpm with the Perry 54x24 prop... </B></div> <bR> <bR> <div> <I><B>May 3, 2002</B></I></div> <bR> <div> <B>On the  first flight we saw the engine reach 3200 RPM during the take off run and 3390 RPM leveled out flying down wind on the first circuit of the field... Observed on an uncalibrated TinyTach...</B></div> <bR> <bR> <div> <I><B>E-MAIL REGARDING CARBS:</B></I></div> <bR> <bR> <div> <B>Subj: Re: Steve on: Fwd: CV carburetor - More </B></div> <div> <B>Date: 08/15/2002 1:05:58 PM Pacific Daylight Time</B></div> <div> <B>From: EaglersNests</B></div> <div> <B>To: paulncathy@pdq.net</B></div> <bR> <bR> <div> <B>Paul:</B></div> <bR> <div> <B>I've been around the Better Half VW engine enough now to point out some tuning clues that accrue from having short exhaust stacks on independent cylinders... If you look at the stack exit on a rich running cylinder you'll actually see occasional quick puffs of black smoke and hear an occasional low level spit or snapping sound that I attribute to after burning in the short stack... Leonard's engine is well run in with 150 hours or more on it and the inside of the stack should be colored gun metal gray after a flying session on AV gas - the stacks were thick with wet black soot that would come off in gobs if you sampled the inside with your finger... On our fresh engines you can expect some oil to be coming past the rings and out into the stack... The residue (may be a little oily) inside the pipes on either AV gas or auto fuel being run several minutes at full throttle should only have the tiniest suggestion of black in it...</B></div> <bR> <div> <B>Using dual EGT's to tune is an interesting and worthy exercise... We have found that the engines will run and maybe even fly (Marginally) on rich mixtures... Mike Ward's engine as I saw it last at the beginning of the carb tuning session (elevation 4000 ASL) was turning 2920 RPM on a prop that had been cut 2 inches per Leonard's suggestion to 52x22 which is the size Leonard was flying at Oshkosh 2002... As I watched Mike's engine run I could see the occasional spit of black smoke at the exhaust pipe exit and hear the snapping / backfire sound - Mike thought it was actually missing... The stacks were oily sooty black on AV gas... The timing light was showing 30 degrees advanced... The Mikuni main jet is the only leaning element of substance at full power and Mike was using #250 main jets... The EGT was right at 1000 degrees on both cylinders... We put in #200 jets and the engine smoothed some with a small increase in RPM - the EGT stayed at around 1000 degrees... We put in #150 jets and the EGT came up to 1050 degrees on the #2 cyl only... The engine turned over 3000 RPM and sounded better... We put a #140 jet in both cylinders and the #2 cylinder showed 1100 degrees EGT and the #4 cyl 1025 degrees... We saw over 3100 RPM and the engine smoothed out some more... Then we put a #120 jet in #4 cyl and ran the engine several minutes at full throttle... The EGT's were matched at 1100 degrees and the Tiny Tach was verified by my Tru-Tach to be showing 3220 RPM... The outside edges of the stack exits were turning grey/brown and the inside was oily with a trace of black...  We pulled the plugs and the porcelain was the nice brown color... Great Plaines and other notable VW authorities say you can lean the VW to 1200 degrees... Given the fact that the valves are the VW weak point and we have done major messing with the heads I'd never ever lean to more than 1200 EGT degrees in cruise... You need to get up to 1300 degrees for best power but should not hold that temp for more than 5 minutes...</B></div> <bR> <div> <B>I have learned that the Mikuni does not like a vibrating environment and will fail if exposed to it... I think the Mikuni runs better with a fuel pump (Mike is running the stock VW pump and so is Leonard) and for sure would have the 3.0 gravity flow inlet valves for the designed LEU gravity setup... We have made Mike's generic engine run decently at idle (800 RPM) and full power (3220 RPM static) on the VM34-??? Mikuni's and have more work to do before saying that these carbs & engine can be run with stable performance under all throttle settings... Mike's throttle quadrant is jury rigged with individual carb throttle cables on the test stand...</B></div> <bR> <div> <B>The adjustable jet needles are looked to for calibrations that are not in our general requirements having little to do with idle or 3/4 - full throttle settings (closely examine the function diagram on the last page of the Mikuni Super Tuning Manual linked to my Mikuni pages and below)... I have read that generally we should keep the circlip adjuster in the middle needle slot to get the best fuel distribution pattern from the needle as it sits above the main fuel jet...</B></div> <DIV ALIGN="LEFT"></DIV> <div> <B><IMG SRC="38df4610.jpg" border=0 width="500" height="609" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></B></div> <bR> <div> <B>I believe that we should stand on the shoulders of those before us and use carbs that are in the center of a suggested range between 26 and 30mm for a 18 HP cylinder... The 28mm carb is right in the center of the graphic plot here...</B></div> <bR> <DIV ALIGN="LEFT"></DIV> <div> <B><IMG SRC="340f5710.jpg" border=0 width="245" height="369" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></B></div> <bR> <div> <B>According to the Hummel Engine website spec we may be getting less than 18 HP per cyl on our 69x92 engines... Leonard was talking 32 HP for the engine at Oshkosh 2002 which puts the 28mm carb at the upper margin of the grid...... On paper my 69x94 engine makes 40 HP and it does turn a 54x24 prop at 3390 in the air which is another way of coming back to the 32 HP engine on a 52x22 prop turning 3220 RPM static...</B></div> <bR> <div> <B>Steve</B></div> <bR> <bR> <bR> <div> <B>Subj: Re: Steve on: Fwd: CV carburetor </B></div> <div> <B>Date:08/15/2002 8:27:15 AM Pacific Daylight Time</B></div> <div> <B>From:paulncathy@pdq.net</B></div> <bR> <div> <B>Hi Steve,</B></div> <div> <B> </B></div> <div> <B>My plans show a VM34, but I know the Leonard's LEU now has 28's on it.  How did you determine that they were too rich at Oshkosh?  Was it as simple as looking at the exhaust pipes and seeing that they were black inside?</B></div> <div> <B> </B></div> <div> <B>Are you of the opinion now that a 28 would be best?</B></div> <div> <B> </B></div> <div> <B>Thanks Carl, for pointing us to the CV Carb web site!</B></div> <div> <B> </B></div> <div> <B>Adios, Paul</B></div> <bR> <div> <B>----- Original Message -----</B></div> <div> <B>From: EaglersNests@cs.com</B></div> <div> <B>To: EaglersNests@cs.com</B></div> <div> <B>Sent: Thursday, August 15, 2002 8:51 AM</B></div> <div> <B>Subject: Steve on: Fwd: CV carburetor</B></div> <bR> <bR> <div> <B>Carl:</B></div> <bR> <div> <B>Thanks for finding this carb site!...</B></div> <bR> <div> <B>I have recently worked with Mike Ward on his generic better Half VW engine that has VM34-??? Mikuni's on it... We had to put a #140 jet in #2 cyl and a #120 jet in #4 cyl to get 1100 degree EGT's on AV gas at 4000 ft ASL and proper running... The smallest jet sold for a VMxx-xxx Mikuni is a #100... My engine runs with #240 jets on VM32-282 carbs...</B></div> <bR> <div> <B>Now go look at that carb sizing chart on the CV carburetor site and you will see that a 32mm carb is the maximum size for a 20 HP cylinder... Right sizing the Mikuni for our application may be helpful... My belief is that you can tinker the larger carbs around to work but throttle response will be delicate because you don't have adequate suction... Leonard is now running 28's but were jetted way too rich as shown at Oshkosh 2002....</B></div> <bR> <div> <B>Steve</B></div> <bR> <bR> <div> <B>Subj: CV carburetor</B></div> <div> <B>Date: 08/14/2002 10:26:52 PM Pacific Daylight Time</B></div> <div> <B>From: WeeMoose@aol.com</B></div> <div> <B>To: EaglersNests</B></div> <bR> <bR> <div> <B>Click here: CV carburetor</B></div> <div> <B>http://www3.telus.net/dougsimpson/CVcarb.html</B></div> <bR> <div> <B>Hope a few of you don't mind a crossposting. I found this website about CV Carbs using Kartoo, (www.kartoo.com). The site has an explanation of how a CV carb works, links to various carb makers, a carb selection to HP chart, and other info that might be of help to anyone choosing a carb.</B></div> <bR> <div> <B>The only thing I don't agree with is the poor acceleration remark, often that is due to a carb being too big or the mid-range mixture being too lean.</B></div> <bR> <div> <B>Carl</B></div> <bR> <bR> <div> <I><B>October 18, 2002</B></I></div> <bR> <div> <I><B>Subj: LEU #33 cross country to Copperstate fly in... </B></I></div> <div> <I><B>Date: 10/17/2002 8:43:20 PM Pacific Daylight Time</B></I></div> <div> <I><B>From: EaglersNests</B></I></div> <div> <I><B>To: EaglersNests</B></I></div> <bR> <div> <I><B>Eaglers:</B></I></div> <bR> <div> <I><B>A number of observations resulting from the Copperstate cross country...</B></I></div> <bR> <div> <I><B>1) We flew 200 miles and visited 4 airports yet did not make it to the fly - in... This gives credence to the homebuilt testing rule that a new airplane will be flown for 40 hours within 25 miles of the designated testing facility... 3 out of the 4 times we've flown the LEU the day was terminated by items needing immediate servicing... I've looked over the flying logs of other homebuilts and find this level of activity normal and the readiness of the airplanes to fly long periods not... My home field isn't suitable for local flying and I feel it important to move the LEU to a field where I can </B></I><I><B>build </B></I><I><B>time...</B></I></div> <bR> <div> <I><B>2) We installed a Grand Rapids Technology Engine Information System... The unit includes the Altitude and Rate of Climb features... The unit operates as advertised right out of the box... It has numerous readings that are managed by setting high/low limits and forgetting it... The usefulness of the instrument is just wonderful... We were concerned that the unit would take too much energy from the total loss battery setup... I use a trickle charger on the batteries and the EIS said we had 13.2 volts when I took off... 4 hours and 200  miles later the voltage was reading 12.4 volts and I had run dual ignition and the EIS full time... It is needless to worry about an onboard charging system for the LEU...</B></I></div> <bR> <div> <I><B>3) The engine had been totally overhauled to have the Hummel Engine reciprocating mass balance method used on the crank... We find the Hummel statement that the balance job will take 85% of the shake out of the engine true... Prior to this balance job you could see visible vibration on every flying surface and that vibration disappeared... The carbs were always a blur and we noted the right carb standing totally still on the new engine at 3000 RPM... The vibration of the carbs has been sufficient to rupture the rubber mounting flanges on both carbs in 19 hours - discovered at Dateland... New flanges may stabilize both carbs in flight... I will try the Sun Tech mercury ring balancer to see if it works on the remaining vibration... Vibration levels now are like you would find in a C65 powered Piper Cub and acceptable...</B></I></div> <bR> <div> <I><B>4) When we stated the newly rebuilt engine the EIS warning light flashed that we were going over 1200 degrees F EGT... The #240 power jets were changed to #280's for 1140 degrees on the high cylinder... The engine would only produce 3090 RPM static and 3290 RPM in the air... This was a loss of 100 RPM and REALLY noticed in performance at the over gross weight of 525#... The engine is stiff and I think the revs will come up after we get some more time on it - currently 5 hours total... I never flew the first engine until I had 10 hours ground running on it... The current engine was showing 1060 F EGT when I landed at Dateland... I will install #260 jets and test before next flight... Changing jets some can make BIG changes in fuel consumption... The first engine had a well documented fuel burn of 2 gallons an hour... The current engine was burning 2.75 gallons an hour - think about it every time you tune the engine and fly...</B></I></div> <bR> <div> <I><B>5) In the engine teardown we saw two negative wear items... One of the valves was not rotating because the new aftermarket rocker assy was not hitting the valve stem in the correct eccentric location... I ground the rocker lateral wear face to move it more to the side on the valve stem... Further the oil pump gears were gauling the pump cover... The metal went into the filter and would go into the bearings on a filterless engine... I had followed the book and pushed the pump drive shaft further into the drive slot on the cam as a function of measurements... That exposed gripping splines on the shaft which caused the shaft to be forced out into the cover as the engine ran... The only clue to the oil pump damage was a pound or 2 reduction in pressure in the 14 hours of running time and an opportunity to open the oil filter and look for the metal which I had not done... Modern engines survive because they have oil filters...</B></I></div> <bR> <div> <I><B>I will do a flight report with the warm and fuzzy stuff on the web site soon...</B></I></div> <bR> <div> <I><B>The LEU flies just beautiful - keep building...</B></I></div> <bR> <div> <I><B>Steve</B></I></div> <bR> <bR> <bR> <bR> <bR> </td> </tr></table></body>