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Archive for December, 2012

Started Preping Engine Baffles – 4 hrs

December 31, 2012 Leave a comment

Monday Dec 31, 2012

Today I installed a ground tab block to the firewall for connecting aircraft systems electrically to the battery ground. I purchased a block from B&C Specialty Products and mounted it direct above the battery so the main ground bolt sticks through the firewall where it will connect to a large ground wire from the battery (-) terminal.

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Here you can see the ground tabs on the aft side of the firewall where Faston connectors will attach. This version of the ground block has 24 tabs.

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I was looking at the routing of the oil cooler lines which brought me to the oil cooler mounting question, which brought me to the engine baffles and cowling. So I decided to open up the engine baffle subkit and start preping parts for it. The baffles can be a big (and frustrating) job so this is likely the first of many posts on the baffle work. I started on page one of the baffle instructions by trimming and deburring these parts. So far, so good.

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Then I deburred the #4 cylinder baffle and match drilled it to these stiffeners.

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I temporarily clocoed the baffle parts around the #4 cylinder and did a fit check of the oil cooler in this location which is the “standard” place to mount it. The firewall is another common place to  mount it with a 3 of 4 inch scat tube porting the cooling air from the baffles to the oil cooler. There is a lot of chatter on the web about cracks developing in the #4 baffle area due to the weight of the oil cooler causing high stress under vibration but Vans updated the baffle design a few years ago to correct this. Some builders don’t feel confident that the new design really fixes the problem and I have read at least one report of the new design cracking. So my options are to either mount the oil cooler on the #4 baffle and reinforce the weak points where cracks have been reported or move it to the firewall and create a duct to pipe air from the baffle compartment to the cooler. There are pros and cons to each approach. I’ll be thinking and researching this question. I’m not sure I am ready to make the decision today.

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I also fit the aft baffle plates to the engine. The one on the pilot’s side took some trimming because one of the bolts holding the #4 cylinder to the engine block interfered significantly.

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There is a little angle bracket that ties the aft baffle plates to the engine block. Unfortunately, one of the fuel injection lines to the spider blocks where this bracket mounts as you see below. The usual fix is to reroute the fuel line slightly.

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I removed two adel clamps on this line and carefully rebent (with just my bare hands) the tube to jog around the mounting bolt. It’s hard to see in this photo but there is at least 1/8 inch clearance now which is probably adequate since this line is pretty stiff and won’t be bouncing around relative to the bracket. I’ll check it again after the bracket is mounted.

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You can see in the photo below that I flipped the adel clamps around on the lower right fuel line so now the tubing is further forward by about 3/4 inch than it was before.

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Completed Control Cables (I think) – 4.5 hrs

December 29, 2012 Leave a comment

Saturday Dec 29, 2012

I continued to make incremental progress today on the firewall forward tasks. I needed to install the second firewall penetration so I knocked that out. I hate drilling the stainless steel firewall because it is tough on drills but it must be done. I start by drilling a 1/8 inch center hole that I enlarge with a 1/4 inch cobalt drill. Then I used a unibit to enlarge it further to 7/16. The shaft of the hydraulic punch is just under 7/16 so I set that up with a 1-1/8 inch punch and it does the rest of the job. Here you can see the punch head installed just before I pumped it up to cut a nice clean hole. Actually I leaves a slight ridge on the inboard side of the firewall but that cleans up pretty easily.

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Here is the pass-through fully installed on the pilot’s side. Ready to receive wires!

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Next I made a new control cable bracket for the fixed pitch configuration (no blue knob) and match drilled holes to attach it to the bottom lip of the panel. It is clecoed on for now.  I will install nut plates later. I replaced the temporary bracket I had been using to lay out the cable runs and routed the throttle and mixture cables to the servo.

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I think I am done with this task now so I applied blue locktite to the screws that hold the servo adapter plate to the sump and torqued them. Then I mounted the servo and installed the lock nuts and torqued those also. I could not get a crows foot on the nuts so I used my fish scale to apply 120 in-lbs of torque using a 5 inch radius arm on the wrench. That is, I applied 24 lbs of force x 5 inches = 120 in-lbs. I installed the mixture cable with all the hardware including the rubber seals which I had removed for all the routing activity over the last few days. Here is a “final” view of the mixture side.

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And here is a “final” view of the throttle side. My only reservation now is the exhaust system and the hangers that will be used to support it. I just hope they don’t interfere with the cables and brackets I worked so hard to fine tune. I expect the exhaust to be delivered any time now since I ordered it a month ago from Larry Vetterman. I hope I don’t get surprised.

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More FWF Progress – 5 hrs

December 28, 2012 Leave a comment

Friday Dec 28, 2012

This morning I finished the modifications to the FI servo and cable adapter brackets. The photo below shows the adapter and the angles of the two brackets. The one on the left is tilted inward 5 degrees and the one on the right is tilted four degrees.

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I took the angle brackets off and marked rough lines on the sides for trimming. This just reduces the weight slightly and provides a little more clearance to the engine mount. This is the throttle side.

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This is the mixture side.

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After I trimmed the angles I match drilled the cable attach brackets for AN3 bolts and applied alodine to the parts. Here is the completed assembly from the throttle side.

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And here is the mixture side.

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I put that aside now until I get my exhaust system installed so I can check clearances to the hangers. So I turned my attention then to the alternator. I was surprised to find no instructions whatsoever for installing this in the Vans FWF kit. After getting a little frustrated with that I went on the Plane Power web site and found instructions in pdf form.  Good thing. One problem was to get the belt installed I had to lower the starter about 1/4 inch. I loosened the starter bolts slipped the belt through, then retorqued and striped the starter bolts.

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The main bracket for the alternator gets installed with two large bolts which I torqued and safety wired (took two tries to get it right).

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The rest was pretty easy and the alternator was hung in about fifteen minutes after that. Of course, it still needs to be wired up.

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I also received two firewall pass-throughs in the mail today from Avery Tools. These are the SafeAir1 pass-throughs which look like pretty good quality. I had time to install one on the right side of the firewall near the brake fluid reservoir. I plan to install the other one on the left side tomorrow.

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Categories: Firewall, Firewall Forward

Throttle and Mixture Cables – 5 hrs

December 27, 2012 Leave a comment

Thursday Dec 27, 2012

Before describing the main accomplishments for today I want to start by showing one of my Christmas presents – a set of rudder pedal extensions from JD AirParts. These are not necessary accessories but I think they look good and will be functional. Here are the two extensions; nicely machined and anodized aluminum.

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They were installed in no time requiring only a hex wrench to attach them to the pilot’s rudder pedals.

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The bigger accomplishment today was completing the routing of the throttle and mixture cables from the panel to the FI servo, including locating the firewall penetration for the mixture cable. I started by making a temporary hanger for the control knobs. It is temporary because I wanted a way to lay out the cables so I could upgrade later to a constant speed prop so I laid out the spacing based on three controls with the prop control in the middle. The actual hanger will only have the throttle and mixture holes so they will move closer together. I used .025 aluminum sheet to make this hanger because I had some on hand. It should actually be .040 or thicker for the real thing.

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Now for a description of the routing. Looking under the panel you can see that the throttle cable runs down under the rudder pedal bars to the penetration near the fuel line fitting. This cable is 44.5 inches long – probably adequate but I may exchange it for a slightly longer one. I think a couple of inches longer might be better. The mixture cable routes over to the firewall recess where I mounted an eyeball penetration on the left side near the bottom of the sloping surface.

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The throttle cable exits the firewall next to the nose gear mount and is almost a straight shot right to the FI servo. To gain extra clearance between the cable and the engine mount tube I tilted the gold bracket inboard about 5 degrees from the “stock” AFP design. I had to drill an extra hole in the AFP-provided part to do this.

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Here is a closeup of the throttle arm. Note it is mounted in the hole with a smaller radius from the pivot point. This is necessary because the control cable does not have enough travel to accommodate the larger arm radius.  This view is in the WOT position.

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This view is in the idle position. The geometry of the cable and the joints all look good.

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This next view is looking back along the path of the control cable. You can see the spacer between the spherical bearing and the control arm (which is 35/64 long) and the clearance between the cable and the engine mount.

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The mixture cable exists the firewall in the recess and turns down along the oil breather tube where I will secure it with standoffs later.

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The mixture cable then turns forward to the bracket I made to mount to the gold AFP bracket. I tilted this AFP bracket inboard a little also by drilling a new hole in the AFP bracket at the angle that gave about the same clearance at both engine mount tubes that the cable passes. This bracket is clecoed on right now but I plan to drill it out for AN3 bolts.

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Again, a closeup in the full rich position.

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And here it is in the idle cut-off position. I am happy with the geometry here also. both cables operate smoothly.

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And here is the view from the front looking down the cable. The spacer on this side is 3/8 inch long which seems to be about optimal.

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Last but not least, I removed the plug in the #3 cylinder and installed the manifold pressure fitting and hose. This hose will be routed to the manifold pressure sensor and the two P-Mags. I also installed the oil filler tube although I have not torqued or safety wired it yet. I want to make sure there is no need to remove it for access before I take that step.

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Throttle Control Cable – 2 hrs

December 24, 2012 Leave a comment

Monday Dec 24, 2012

It’s Christmas Eve so I did not a lot of time on the project today but I did do some preliminary work on the throttle cable routing. First I went by the hardware store and bought a 17/64 cobalt drill bit so I could enlarge the holes in the eyeballs for the throttle cable which is .265 diameter. Then I drilled out the eyeball, installed the cable and began messing around with the routing while trying to figure out where to mount a bracket to tie down the control cable just before the servo. There are many variables to play with including the amount of thread engaged with the spherical rod end, the location and angle of the bracket, and the hole in the servo control arm selected. Initially I was using the outer hole in the control arm but I found that the extra motion was causing the cable to come up short at the instrument panel bracket. I think this cable is just barely long enough. I moved the spherical bearing to the inner hole in the control arm and adjusted the nominal angle of the arm so that the cable is perpendicular to it at the mid point of the throttle stroke. You can see that in the two pictures below. The first is at full throttle and the second is at idle. Note the angle of the control arm relative to the control cable. They are perpendicular half way in between these two positions.

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I also adjusted the tie down bracket to get the most clearance I could between it and the engine mount tube. There is about 1/2 inch clearance in this configuration. I think that is enough to allow for engine motion on the mounts. But before I drill this and lock it in I will sleep on it. Sometimes things I forgot come back to me when I give them time to season a little.

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Starting to Install Fuel Servo and Control Cables – 4.5 hrs

December 23, 2012 Leave a comment

Sunday Dec 23, 2012

This morning early I unpacked the components of the Airflow Performance fuel injection. These were included with the engine I bought from Aero Sport Power but were not installed when it was shipped. I have no idea how this goes together. The AFP manual is included but frankly it is less than straightforward. What I really need is step by step instructions based on my aircraft configuration. I am building 7A with IO-360, AFP fuel injection and vertical induction. That is not a “standard’ configuration supported by Vans. The closest thing they support is an O-360 in a 7A so you can’t count on the plans to always be right. I haven’t been able to find any clear directions on the forums so I’ll just have to try to figure this out as I go. I’ll document it as best I can in case anybody else needs the help.

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There is an adapter plate that clearly looks like it mounts directly to the induction sump. And based on some of the information in the manual I gather that the two angle brackets mount to that adapter. But the angles have to go on first because the screw heads are not accessible after it is installed. I did some fit checks and I am beginning to see that the throttle control is on the right side of the servo and is further forward than the mixture control which is on the left. So the short bracket goes on the right and the long bracket goes on the left. At least one photo in the AFP manual seems to support this. But there are multiple holes on the angles and you can adjust the position forward and aft by selecting holes. What to do? More fit checks using the brackets and servo and a control cable seems to suggest that the angles should be set with the most forward hole in the angle mating with the most forward hole in the adapter as you can see below. I went ahead and torqued the screws for this but I could change it later if necessary.

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Then I mounted the adapter to the induction sump. For now the screws are dry but I will use some locktite on these when I do the final torquing. Locktite is recommended in the AFP manual.

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Here is the adapter from the right side.

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And here it is from the left side with the fuel servo installed. I found four free running nuts in the ASP package along with four all metal lock nuts. I am guessing that the free-running nuts are for initial fit checks like this. At least that is what I am using them for. You can see the mixture control arm is about 6 inches forward of the flag-shaped area of the angle bracket. That is where I will mount an angle to hold the mixture cable.

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The right side shows the throttle control and again the flag-shape area of the angle bracket is about 6 inches aft of the control arm. It’s starting to make sense now. I can see now why the Vans plans for an O-360 show a firewall penetration near the fuel line fitting for the throttle control. It is a pretty straight shot and the angle bracket can be used to secure the cable. Now I feel confident I can punch the hole for an eyeball feed-thru in that area. I sighted along the projected path of the cable and see that the feed-thru should be between the fuel fitting and the nose gear tube of the engine mount (see below). I marked the center of the hole location and drilled a 1/8 inch pilot hole. Then I enlarged it to 7/16 using a step drill.

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Fortunately a friend loaned me a hydraulic punch kit with a 1-1/8 punch and it requires a 7/16 center hole. For clearance reasons I had to put the head of the punch on the cabin side of the firewall. Here you can see it set up just before pumping the handle to punch the hole.

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Wow, the hole came out nice and clean. I barely had to deburr the interior edge. I used the eyeball parts as the template to mark the locations of the screw holes and I drilled those with a 1/8 inch carbide drill bit. Notice that I rotated the hole pattern about 45 degrees from horizontal so it would fit better.  To have better access I removed the fuel servo before punching this.

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Then I screwed the eyeball parts into the newly made penetration. It is ready to receive the throttle cable except the cable is .265 diameter but the hole in the eyeball is .250. I need a 17/64 drill bit to open this up just a little.

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Hung the Engine! – 8 hrs

December 22, 2012 Leave a comment

Saturday Dec 22, 2012

Well the day has finally arrived. It is “hang the engine” day. As far as I could tell there was nothing left to hold me back from putting the engine on the mount so I invited my friend Scott over to help. We were both excited. First thing we did was remove the sides of the crate to expose the engine on the pallet. Here Scott poses with the engine as we were getting organized.

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This is just another good shot of the IO-360 from Aero Sport Power. Isn’t she prety?

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Then we rotated the pallet 180 degrees to get the engine oriented properly with the fuselage. To get the hoist aligned with the hook directly over the engine lift point we had to lift the pallet up on three stacks of 2×4’s. At this point we had verified that all joints of the hoist were properly tightened with retainer pins installed as required. Then we lifted the engine just enough to take the weight off the attachment brackets to the pallet so we could get the bolts out.

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Then up she came to the approximate height for mounting. Like everybody says, it is a bit uncomfortable having this thing hanging above a concrete floor.

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Then we positioned it roughly for the first bolt installation. Here I am with my pointy pillow hair. It turns out we had a water leak in our house yesterday causing a flood and significant damage. All the water was turned off while workers were in the house pulling up carpet and cutting out wet dry wall so I could not take a shower this morning. Don’t tell Scott (I think he figured it out by the smell). But we had scheduled this engine hanging earlier in the week so I was determined to press on.

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We did not take pictures during the bolt installation process. We were too focused on the job. But let me summarize by saying we followed the instructions on the Vans Air Force web site. The first two bolts were not too bad. The third bolt gave us the most trouble because we just could not get the holes to line up no matter how we wiggled the engine or adjusted the hoist. But we finally got it and with the first three bolts down tight the fourth one went in without too much difficulty.  I had to use two small washers under each nut to put the cotter pin holes in the right spot relative to the notches in the castle nuts. Here I am again with the engine hung and all bolts tight.

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Here is one more picture as my joy motivates me to hug the newly hung engine.

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After that I still had enough energy to start fitting some of the easy hoses between the engine and the firewall. Here is the main fuel line from the firewall to the mechanical fuel pump inlet (with red fire sleeve). The fitting on the fuel pump as it came from Aero Sport Power is angled back at about a 45 degree angle but the Vans drawing shows it going straight down. I actually think ASP did this on purpose because it keeps the hose from hang down quite as far below the engine. This may provide more clearance for the fuel injection control cables so I will leave it this was until the fuel servo is installed and I can see how those cables will route.

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In this picture you can see how the hose hangs down slightly below the fitting at the firewall. With the fuel pump fitting pointed straight down this hose will hang down another inch or two easy. It looks like the control cable will have a clearer shot with this routing. Nothing is torqued yet so I can always adjust it later.

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The engine breather tube attaches to the firewall with an Adel clamp (center bottom below). This is temporarily in place because I have to install the exhaust system first to determine where to trim the bottom end of the tube so the breather blows directly onto one of the pipes. I also attached the two oil cooler lines temporarily for fit checks.

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The mechanical fuel pump came with a 45 degree angle fitting on the exit port. That must be removed and a special 90 degree fitting from the firewall forward kit is installed. The fitting has two ports, one for the fuel line to the FI servo and the other gets a restrictor fitting and that goes to the fuel pressure sensor on the manifold block. Installed the fittings using a little fuel lube on the o-ring and threads and hooked up the hose to the manifold.

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This is going well so far but this is the easy part. The firewall forward kit for the O-360 is working out fine up to this point but there is still a long way to go.

Categories: Engine, Firewall Forward