Bob and Karen Brown's Airplane Building Project

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ENGINE AND FIREWALL FORWARD

There are such a myriad of things to consider, and so many myths, legends and strong feelings held by knowledgeable people it is difficult to know what to do. Should one go with a "Lycosaur" air cooled reciprocating engine and spruce it up with electronic ignition?? Should one install an auto engine conversion "kit" like an Eggenfellner Subaru? A V-6? A Turbine?

There have been many emotional discussions on the RV List about engine choices, with many good points made on (al)most (all) sides.

We listened to a lot of advice from people we know that "know", did a LOT of research and tried to sort through all of that while trying to maintain an objective viewpoint... So here goes...

LYCOSAURS

WEIGHT VS. POWER

AUTO CONVERSIONS

OUR CHOICE...

PS-After all of this, we received the engine as configured above, but after hassling with the fit of the Airflow Performance Servo with the Ryton sump and the tricycle grear configuration, we decided to switch to the Silverhawk Fuel Injection system (the non-certified version of the Bendix fuel injection system).  This is a bolt-on option that I have helped neighbors install.  I know there will be a slight performance trade off, but the airplane will still do 200mph...easy.  I'm OK with it and will keep you updated.

PPS: Keep your eyes open, Superior has had some problems with failures of the Ryton sump when coupled with electronic ignition systems utilizing "wasted spark" technology, such as the Lightspeed system, the Jeff Rose system and the P-Mag/E-Mag system.  One of my neighbors has lost two sumps to this problem, which involves an accumulation of fuel/air mixture in the induction area of the sump that ignites during the period of valve overlap at startup.  Because of the design of the P-Mag system, they can program the firmware at the factory to change the timing during the startup phase, so this should not be an issue with P-Mag/E-Mag technology.  For what it's worth, this problem has not occurred with tricycle gear aircraft, nor has it occurred on fuel systems with a purge valve setup.  Stay tuned.

		(Click any picture for a larger view with an explanation.)
Picture from Eagle Engines of the Xtreem 360	Engine Mount Installed	Lower Cowl Attachment Plate	Hinge for Attaching Lower Cowl	New Gusset for Right Engine Mount
Plan of Firewall Penetrations	Firewall Penetration Locations	Nosegear Access Hole	Bob Locating Penetrations on Firewall	Firewall is marked for drilling
Placement Issues	Brake reservoir	Manifold Pressure Sensor for ACS 2002	F7127 Doubler Plate	F7127 Doubler Plate
F7127 Doubler Plate	Battery Box for Odyssey Battery	Battery Box Paint	Battery Box Ready to be Mounted	Battery Box Mounted on Firewall
Firewall Installations	Battery Cable Installed	Interior Shot of Heater Box	The engine is hung on August 9, 2005.  Bill Wallace, Gary McCormick and Jim Aanes were on hand to help.	It is deceptive to imagine how much work is left once you reach this point...
Here is a shot of one of the P-Mags.  They are a work of art (from an engineering standpoint).	Just a few wires back there, move forward a few frames and see how quickly things change.	The flange from the induction snorkel is on the right, the Airflow Performance Fuel Injection servo on the left.	This is how I had the fuel lines routed on the Airflow Performance setup.  The line going up and to the left is going to the ACS fuel flowmeter.	This is the purge valve bracket I fab'd.  It consists of a bellcrank linkage operated by a locking pull cable in the cockpit.  It is springloaded to a failsafe condition, so if the linkage or cable breaks, the purge valve actuating arm will be held in the "run" position.
Parts to make up the ignition harness for the P-Mags.	One wire a time, one hose at a time, pretty soon, you have a real mess.  It's not as bad as it looks, but it is more work than I had realized.	This is the original heat muff.  It has both inlet and outlet tubes pointing the same direction.  I later contacted Robbins Wings, who makes these for Van's and had them fab another heat muff with inlet and outlet tubes clocked about 100° from each other so that the inlet tube points forward, which allows a good fit as the scat tube comes down from the lower right baffle floor.  The outlet tube then exits the muff and proceeds aft toward the firewall.  This eliminates the need to make a 180° turn with the scat tubing.	This is the critical fit area where the purge valve arm is closest to the upper cowl.  The purge valve arm will only be in this position before engine startup or at shutdown.  The plenum will be a close fit in this area.	This shot shows the hole I cut in the lower cowl when I thought I would just fab up a blister or rework the line of the lower cowl to fit the AFP Servo.  I ended up glassing this cutout closed using the piece I cut out.  With the help of my neighbor Henry (your friendly neighborhood fiberglass expert who's building a Lancair IV-P) helped me do a perfect repair of this hole.
Clearance around the AFP servo was not good.  The geometry is compounded by the combination of a Ryton sump, the nosewheel configuration, and a crossover exhaust.	With these kind of clearances, there isn't room to rotate the servo, since the mixture and throttle arms would not fit on the left side either.	This is a control arm for the throttle that my friend Gary made on his mill.  I didn't end up using it because I switched from AFP Fuel Injection to a Bendix style system.	Here is the ACS fuel flow transducer.  I fab'd a steel bracket to mount it in the horizontal position with the wires on top as spelled out in the installation instructions.  I also fab'd a steel support bracket for the oil line to the prop governor.  Where the oil line goes through the bracket, it is protected by a short section of fuel line.	Here is another view of the bracket I fab'd for the fuel flow transducer.  It bolts to a boss on the engine case.  The bracket took me awhile to figure out, there are lots of angles to deal with if you want the transducer to sit horizontally.  Something else to notice in this shot is the firesleeve on the alternator wire.  I sleeved all wiring in the engine compartment with this stuff, which is a silicone covered fiberglass hose with a temperature rating of 1600F.  This should ensure a long life for the wiring.
This is the induction inlet on my friend Ken's Harmon Rocket.  As you can see, it is a very cool setup.  Unfortunately, unless you want to run unfiltered air all the time, there just isn't enough room on the standard RV cowl to glass in a setup like this...too bad, because I think it is a superior way to get air into the cowl.	This is one of the four "pieces" of the baffling.  Assembling and fitting the baffles is an on/off/on/off...operation.  I put almost 60 hours into finishing the baffles.	This is the new heat muff.  Notice that the lower tube (the outlet) is facing aft.  This makes for a much neater fit.  I riveted a 2" aluminum flange from Aircraft Spruce to the lower right baffle floor.  An aluminum screen was used between the flange and the baffle floor to keep junk/bugs out of the heat system.	This pic shows the baffles essentially finished and ready for the plenum.  Before the plenum is laid up using carbon fiber, I have decided to make a plug mold using foam, which I'll finish with Bondo before laying the glass on it.  I'm doing it this way because I am going to make at least two plenums on the mold.  One will be for me to use later on in case I need it, the other will be for a friend.	This shows the corner where the oil cooler will mount.  Instead of using .063 here, I elected to use .125 angle for the reinforcing pieces.  Time will tell whether or not that will stand up to the vibration this area sees.
	I made the decision to move the voltage regulator to the firewall for future access.  The ACS amp transducer is the little green thing visible in the lower left corner, with the amp limiter to its right.  Notice the wiring is all run in firesleeve.	This was the previous location of the voltage regulator.  Once the top skin was riveted in place it would have been very difficult to access this area without an access panel, so I decided to design the subpanel architecture for maintenance access without installing top access panels and moved the voltage regulator and associated wiring.	This was the setup I had for the AFP Servo at idle position	Here is the AFP with the control cables positioned at full throttle.
Here is a finished firewall penetration.  There are two of these on the firewall.  I made stainless flanges, riveted them to the firewall, then ran the wires (which were already sleeved in firesleeve) through a larger piece of firesleeve.  The larger piece of firesleeve was then injected (on both sides of the firewall) with Firestop2000 caulk and a stainless hose clamp was used at both ends to secure the firesleeved wires entering the larger sleeve.  If this baby fails, it's gonna take a helluva fire.	View looking downward on the right side of the engine.	This shows where the purge valve cable enters the baffles and is secured to operate the purge valve bellcrank.	Here are aluminum washers I fab'd from two pieces of .187 aluminum.  So that the baffle mated well to the engine case, one of these washers was made with a taper using a file.	This is a view of the right aft corner of the engine baffle showing the return line from the purge valve.  To the left of that is the opening for the ignition leads.  I bought a neat bushing from Spruce that secures the two ignition leads that enter here.
This is the BEAUTIFUL MT prop I chose to use.  I purchased it from Eagle Engines.  It is an MTV-15-B/183-402.  It is certified on Lycoming engines with no RPM restrictions.  It is an all aluminum prop with a blended airfoil design.  It weighs 9lbs less than the Hartzell blended airfoil prop.  It includes the spinner, cutout plates, backing plate and the whole thing costs just a few hundred more than the Hartzell.  The quality and workmanship on this prop is incredible.  Can you tell I think it is a thing of beauty?	Bill Wallace and Gary Brown came over and helped hang the prop.  It's nice to have an A&P IA and multiple RV builders within shouting distance of the house...I can't say enough nice things about these guys.	Here is a close-up of the backing plate.  It is beautifully finished and balanced with the rest of the assy.  The backing plate, blades, hub, spinner and cutout plates are all numbered to maintain balance.	Here's a close up of the spinner.  It is a kevlar layup in a radial pattern...painted with a perfect gloss white finish.  It's a little more pointed than the Van's spinner, but it's not quite a "Madonna" spinner.	The MT spinner is on the lower shelf, the Van's spinner is on the top shelf.  You can see the MT spinner is a little longer and has more of a point.
Here is a reference line drawn 2" aft of the skin.  You then put the cowl in place, measure 2" forward and make the cut.  I cut it a little long and then trimmed it a couple of times to get it as close as possible.	Here's the upper cowl after the cuts.	Here is a shot showing the fit.  This was a high pressure cut, I sure didn't want the Dremel tool to get away from me and go ripping holes at odd angles here.	After the upper cowl was cut, I taped the lower cowl to the upper cowl to measure 2" forward in preparation for cutting the lower cowl.
Here is the fit of the front of the cowl to the spinner backing plate.  The distances I used are 1/8" at the top of the spinner backing plate and closer to 1/4" at the bottom to allow for movement that will occur as the motor mounts find their eventual position.	Here is a front-on view of the spinner/upper cowl intersection.	I used a Dremel with a fiber reinforced cutoff wheel to cut the glass.	Notice the latex gloves and the vacuum tube...I had another arm implanted so I could do this...just kidding!	Here's the cowl as it's cut and fit to the fuselage.
I will use stainless steel Camloks to secure the upper and lower cowl halves to themselves and the fuselage.  The strip shown here cleco'd to the lower cowl was fab'd from an .063 aluminum strip.  I used a unibit to drill holes where the strip needed to bend around the shallow radius at the front of the cowl.  Once these holes were drilled, I simply laid out the lines and cut the angles on the bandsaw.	Here you can see the Camlock receptacles riveted to the aluminum strip.  The aluminum strip will later be bonded to the lower cowl using a mixture of resin, milled fiberglass and microballons.  I will use soft rivets to secure the strip to the lower cowl after the resin bonding mix is spread on the aluminum strips.	Here is the fit of the upper and lower cowls as viewed from the front.	Here are the Camlocks attaching the upper cowl to the lower cowl.	This hinge strip will be bonded to the lower cowl.  This will allow the lower cowl to be removed by pulling one pin on each side.
This shot shows the ugly hole I cut in the lower cowl to fit the bottom fitting on the AFP Servo.	Here's the upper cowl before cutting the glass for the oil fill door.	Here is the camlock receptacle strip after bonding to the lower cowl.	Here Bill Wallace is prepping the lower cowl before we repair the cutout.	Here are the pieces we had to glass back into place.
Here is the cowl fully repaired and ready for my next idea...	I know this is kinda out of place, but this shot shows the fit of the spinner to the cowl.

Last edited 09-Jan-2006