Tag: Engine

It’s coming to an end…

On May 27, 2019

So here is the catch up post from my previous one that was 2.5 months ago.

I fabricated some mounts for my newly purchased landing lights. It wasn’t too hard and I think they will work for now and maybe longer. I purchased a simple wig-wag circuit from Amazon to provide some recognition. It worked well, but the way I wired them to use a single DPST switch, I was not getting the expected behavior when in wig-wag mode. The problem was solved by adding some diodes to the wiring. Once that was done, everything worked great. I’m slowly learning how all of this electricity works.

I rebuilt my parking brake with new seals. Upon inspection of the internals, there were some serious burs in the passageway that houses the “valve” of the parking brake. After filing those away and putting some new seals on, it seems to be working as advertised with no leaks.

I finished the skylight over a few days. This was a pretty intense operation with all the holes that needed locating and drilling. I made a mistake when I was cutting the skylight strips that sandwich the skylight with the skylight ribs, so I had to order a new one from RANS. Surprisingly, the strip I ordered was larger. It was double the width and almost three times the thickness (1″ wide and 0.050″ thickness if I remember correctly). Since I didn’t want to have a lopsided plane, myself and another builder got our hands on some Al sheet of a similar thickness and cut some new strips for the skylight. Since I had already drilled the other ones, the new ones were mostly a quick transfer operation. I also trimmed my skylight short of the tabs on the aft side of the skylight where it is supposed to capture tabs that are welded to the fuselage. I really didn’t like myself at that point, but the fix proved to be very simple. The skylight is approximately 1/8″, so I made two strips of Al to sandwich the sky

light and then bought a 1/8″ thick Al bar from McMaster to fill the gap between the two strips and act as the connection to the fuselage. It turned out really nice and I’m pleased with it.

Once I painted everything for the skylight and windshield, I set off on installing it. This was pretty straight forward, but time consuming with all of the rivets and clekos required. My one fiasco involved my attempts to put a silicone fillet on the edges of the parts to avoid getting water into the cockpit. It is a skill I haven’t quite mastered yet.

The big annoyance in this process was the brass washers that go on the inside of the windshield so it doesn’t have a rivet right next to it. The correct way would have been to place these rivets in there locations with a dab of silicone prior to attaching the windshield to the plane. If you don’t do that, then be prepared for an annoying hour or more trying to get washers to stay on rivets while you pull them. I had to drill out three rivets that had washers pop off during installation. The fiberglass windshield hold down strip does not tolerate much drilling.

The boot cowl went on without much fuss. I would recommend super gluing any washers you will use for spacers on the tabs of the fuselage to make the process go a bit smoother. Something I haven’t done yet, but will soon is put a bead of silicone in the crevice that is created in between the firewall and boot cowl to better seal off the inside of the cabin.

With the windshield and boot cowl installed, the engine was ready to be started! I made preparations by trimming the spinner and locating the holes in the backing plate for attaching the spinner. My one word of advice here is to be very particular about lining up the spinner and the backing plate. Any offset will affect the spacing/interference with the prop hub. I ended up with some slightly over sized openings in the spinner, but it doesn’t look too bad at all.

Due to an error by me while reading the prop instructions, we set the pitch of the prop to what we thought was 17 degrees. My prop is a 75″ Whirlwind and the starting point from WW is 15 degrees. On initial run of the engine and a subsequent full power test, I was only able to produce 4300 RPM. Rotax wants to see 5000-5200 as a static RPM, so I was a ways off. We leveled the plane and then set it to 15 deg. That proved to be too flat and I called off the static runup when I hit the engine’s max rated RPM of 5800. It took us 3 more tries of fine tuning the prop to get a static RPM of just below 5300 which we considered good enough.

I had a small issue with my mag switch wiring, that was discovered during the engine start day, but it was a simple fix. I am using the ACS ignition switch and there are two terminals labeled the same, but do not do the same thing apparently.

We did a quick carb balance, set the idle, and everything was going well. It was exciting to get to this point as I had been thinking about it for years.

Once the engine was started I set off on all the tasks I had left before I could have the plane inspected. I went ahead and set a temporary date with the DAR so that would be scheduled and I would give myself a more concrete timeline to get the plane finished.

This involved installing the wingtips and wing tip lights. I had a lot of trouble with screw holes not aligning even though it fit very well before I painted and installed them, so that was annoying. Maybe the paint was the culprit.

I trimmed and covered the remaining interior closeouts. I had to modify the closeout right behind the seats quite a bit to clear all of the wire/hoses/etc. that were passing through it. I used the same Sunbrella fabric that I had used on the baggage. This time I used a spray adhesive product from Loctite that worked tons better than the 3M Spray adhesive. Definitely recommend.

One of the very large tasks that I had left to do was fitting the cowling. From start to finish this took about 3 days of working the whole day. I would not do it with less than two people and just take your time. As hard as you work to get the cowling to fit close to the boot cowl, the receptacles and 1/4 fasteners are not a tight enough fit to keep the upper cowling from moving slightly away from the boot cowl. I did not paint the strips that the boot cowl attaches to and it looks bad. When I paint the cowling I will use a brush to touch up those strips and I think that will hide the gap very well. I had issues with the lower cowling hitting the radiator, so I had to trim the exit to be just forward of it. Consequently it sticks out a little below the cowling, but I didn’t like the though of the cowling sitting against the radiator. I also had interference where the forward inlet for the radiator was touching the engine mount tubes. I ended up clearancing the material away from the tubes. This all came to a new point when I installed the radiator duct and then the cowling came into contact with that, but I am leaving it for the time being. I don’t think there will be much movement there and it is a non-critical part.

I had some additional trimming in the inlets in front of the cylinders to clear the engine, but that was very straight forward.

I have the S-6 setup for my cowling and the molds didn’t seem to be the best. The lower cowling joggle at the inlets is angled outward so you have to fight with it to get the upper cowling on. The only solution is to trim the area down to make the angle somewhat better. The lower cowling is also not symmetrical which I think is a mold issue and not a design issue. Oh well, it will still fly. I have a carbon cowling and after working with a fiberglass cowling, the carbon seems much nicer to work with and it’s lighter. It also will lighten your savings, so that should be considered as well.

After getting the cowling finalized I did some final taxi testing to test out the handling of the airplane on the ground and see if I had any obvious cooling issues. Everything went well and all of my instruments seemed to be operating correctly and smoothly.

This gets us to the inspection which will be another post on its own and will include the flight test.

(100 hrs)

Jan-Feb

By Ryan

On February 5, 2019

In S-20

It’s been cold and I live far away from the airplane, but progress continues. After 4 years I have also apparently run out of clever titles. Maybe next time.

So here is the update blast.

The wing is rigged. I need to verify that the rigging is still correct once I torque the wing connections. Rigging the flaps was relatively easy and all that is left in that system is painting the exit covers after trimming them for the jury strut. I started to rig the ailerons, but I haven’t adjusted the cable tension and therefore have to wait on that. Once I get the ailerons rigged, the plane as a whole can be considered rigged unless something makes itself known during flight test.

In other wing news, I trimmed and fitted the flap gap seals that bridge the gap between the wing trailing edge and the flap leading edge. I moved them to be about 1/16″ higher than the top of the flap hinge to allow easier access to the flap hinge bolts and avoid trimming the entire length of the gap seal. It was a little sad to drill holes into the aft spar, but progress waits for no one (it only waits on complicated ideas from my brain that take time away from actually building).

For the lubrication system I finally figured out some hose routing that I was satisfied with and I seem to have avoided buying any other hoses. I did use two 45 degree adapters at the oil pump housing to allow a better route for the hose. So the oil hoses are installed now and the bolts have been safety wired. I will have to remove one hose to add some oil to the cooler initially, but no big deal. All that is left for this is to add oil and pressurize it to make sure it gets where it needs to go. I also installed a cooling fan to the oil cooler to increase the cooling capability. Some other S-20 builders have had oil temp issues and they have solved them in various ways, so we shall see if my install is any good shortly. 🙂

I redid the coolant hoses this past weekend, because I didn’t like all the worm gear hose clamps I used. I changed most of them to Oetiker stepless clamps and then used self tensioning Oetiker spring clamps for the removable sections. It looks much better. I also used the stepless ear clamps on some of the fuel lines I had not already assembled.

On the fuel side, I am waiting on some new hose clamps to secure the header tank. Once this is done I just need to do a final check of all the fittings. I am also installing some aluminum heat shielding to the fuel hose that goes from the gascolator to the fuel pump. It passes awfully close to the muffler and I don’t want the fuel getting too hot.

I have added some header wrap and aluminum heat shield to various parts of the exhaust system to try and help protect some components in the cowling. Time will tell how that works. The exhaust system is completely installed and the exhaust nuts have been torqued.

I have some minor wiring left to do. This involves the wires to the starter. I hope to complete this in the next few weeks.

I installed the throttle and choke cables. The only control cable not installed is the parking brake, which I am planning to do this weekend.

Looking ahead to this weekend, I am planning to install the jury struts, final install the fuel system, finalize hose positions forward of the firewall, start to fit the interior, bleed the brakes, and maybe start some fuel system tests.

(30 h)

Enter a caption

Fuel shutoff valve offset mount

So Close

By Ryan

On December 31, 2018

In S-20

Not much exciting things to show since the wings went on. It has been a lot of wiring to wrap up the avionics and also to get the engine wired up. But, that is coming to a potential end and I wanted to get something written down before the end of the year.

(If you’re reading this on the 31st of December 2018, there are no pictures because my iPhone doesn’t like to be below 30% battery when it is 32 deg F or below. I’ll get some photos tomorrow and add them to the post.)

The avionics wiring is complete. I will make the wire runs a little prettier, but all the wires go to what they need to go to and nothing exploded. The wiring for the engine is almost complete. Currently I am working on finishing the wiring for the ignition/mag switch which will complete my engine wiring.

Hoses on the engine have been a not so fun endeavor. The hoses that are giving me problems are the oil hoses and specifically the hose from the oil pump housing to the oil cooler. The provided hose does not lend itself to any sort of acceptable routing and I fussed with it over the course of a few weeks before giving it up. I will have to make my own hose for that run, but I have put it off to accomplish some other tasks I had put off previously. I’m not sure if it was in a previous update, but I fabricated a hose to go from the firewall bulkhead fuel fitting to the gascolator and installed the Rotax fuel hose to the gascolator. I still need to install the return line fuel hose and the fuel pump vent hose. I also will make a vent tube similar to the oil tank breather vent for the fuel pump vent.

I was fitting up the radiator duct a while ago and realized I needed to install the oil hoses which led to me figuring out the fun in the paragraph above, so it is currently waiting for me to finalize the hoses. Something that came up with another builder is making an access panel in the radiator duct so the oil hose at the bottom of the engine can be accessed without removing the duct. It sounds like a good idea and I need to get some aluminum to accomplish that.

Probably should have put this sooner, but I installed the oil tank mount brackets. These are what sort of cradle the oil tank and get riveted to the engine mount. I hope to never have to remove those rivets. The manual calls for the use of pan head screws, but I had a hard time tightening the nut on and replaced them with some hex head bolts which worked fine. One thing spotted by someone else was that the heads of the screws or bolts will touch the oil tank. By using some plastic edging material on the aluminum angles, the tank is offset enough to avoid this.

Another big item was finally diving into the header tank. I had put it off for a year and then bought an updated version from RANS and then put if off for another few months. I installed all the fittings into the tank, installed the mount for the new header tank. I also added a piece of aluminum angle to the read of the mount for added strength since the forward attach locations didn’t do much for the aft part of the tank and it will be relatively heavy with fuel in it. I also had to relocate the tank sump location. I marked it and then cut through the fabric. What I should have done is fabricated a new exit ring, glued it where I wanted the hole, and then cut the hole. Now I will fabricate the ring and glue it, but I probably could have gotten a better finish by doing it differently. I patched over the old opening with some extra fabric from cutting out some inspection cover holes. I still need to run the fuel lines from the wing tanks and to the firewall.

I final installed the flap lever. This was frustrating because somethings are off center and require some odd washer placement. There are also bushings to be fabricated and I don’t have a great way for getting those cut perfect, so I end up putting them on and taking them off a lot. In the end I added some washers as well because the right rod end would hit the fuselage frame when I tried to move it to the last detent. I added washers to center the cables better and avoided this. It is still close, so I may file some of it away to provide better clearance. The material that would be filed away is not a structural tube, so I think it will be safe to do.

Things that are up on the list are installing the jury struts, installing flap gap seal, rigging the wing (and control surfaces), finalizing the oil hose issue, installing fuel return/pump vent hoses, and finalizing the routing of wiring on the firewall forward side.

My engine monitor has also progressed quite a bit. I had thought my software was in a pretty good place and then I installed it into the panel and found some bugs in the data acquisition and sensor conversion code. I fixed those and now my only issue is not understanding how to auto start the application after booting and I need to integrate a real time clock into the board so it actually keeps track of the date and time. The latter should be the easier one to fix and I just placed an order for an updated PCB.

In related aerospace news, I am finally graduated from Iowa State with a B.S. in Aerospace Engineering! It was a crazy 3.5 years to get to this point and it took lot of hard work. A lot of thanks goes to Maria for agreeing and supporting more school. I also owe a lot to all the friends who shared the misery of engineering school and the large group projects that accompany it. It was a ton of fun to go back to school and intern with some exciting companies. I’m looking forward to a fun career.

I learned a lot of new stuff that has guided me toward some neat projects that I am hoping will turn into big things. I am really interested in manufacturing composites and hopefully some structural composites as well in addition to making parts from metals and plastics. I’d like to think I could make a business out of it at some point, but there is a lot of learning and tool acquisition required before that point. I have some neat ideas for upgrades to the RANS and also some standalone ideas, but they will have to wait till the RANS is actually flying.

(40 h)

Time marches on

By Ryan

On October 27, 2018

In S-20

Lots of good stuff in this update. No major steps completed, but a lot has been done to support some big tasks soon.

Since the last update I have been mainly wiring the panel and installing avionics. I am using fuses in my plane, so the first thing to do was located the position of the fuse blocks. I located them on the firewall. After that was done, I began to install switches and wire them to the fuse blocks. I also began making the radio and transponder rack connectors. My setup is pretty simple, but the G5 acts as an altitude encoder for the Appareo Stratus ESG, so they had to be tied in. The radio was the most involved device as it has headset jacks and some external audio jacks. I wired the left and right ears backwards, but that is an easy fix.

The hardest thing about the wiring for me is trying to keep it neat and functional. It’s hard to see where things are going without all the wires and then it’s hard to route the wires when they are a mess. It has taken a lot of time to try and get them routed sufficiently, but it is getting there.

Another issue I had was a switch I have on the copilot side to actuate the trim servo. I am using a momentary SPDT switch and I had to buy relays to make that switch work because the trim servo works by changing the polarity of the wires depending on which way you want to go. This is an ongoing issue. I just haven’t sat down to fix it.

Mounting a heater in the plane has been a battle I finally found a place that is decent, but it definitely is biased towards one side of the cockpit. An idea I have is to maybe create some ducting to help with that, but that will be after it flies. I need to keep moving and not spend a ton of time on stuff that is good enough to fly.

I’ve also got a beta version of the front half of the case for my engine monitor, so I have temporarily installed it to get some wiring done. I am working on finalizing the back half of the case this weekend and I hope to have it printed sometime next week. It looks great in the panel. My software work on it at the moment is just changes to fix any issues with the computer talking to the engine sensor data acquisition box.

I wanted to put the magnetometer in the wing, but I didn’t make any provision for this prior to covering. To solve this problem, I designed a mount to hold the magnetometer on a tube inside the wing that is accessible from an inspection panel. This was a cool solution and it seems to work great. I ran all the associated wires for the magnetometer and the G5 rewarded me by saying it was connected and everything was working great.

Onto the aircraft structure work. I have installed and rigged the elevators. It wasn’t as hard as I thought in the beginning. The big issue I found was stick interference with the interior cover panel that is forward of the seat. That will be easily fixed by just trimming that panel since it isn’t a structural part of the aircraft. Myself and another builder elected to replaced the riveted aluminum tube on the elevator push pull tube with aluminum split collars. This will allow me to change the elevator travel limits if I find that I have rigged it incorrectly. They work great as far as we can tell and seem to be a good solution. Another change was to exchange the bolts that attach the elevator control horn to the elevator with drilled head bolts. This allows them to be safety wired since the original bolts are relying on a nut plate for the locking feature of the bolt.

I got the wingtips fitted and trimmed. The only thing left is to add the aft rib to the wingtip which I will do when the wing is installed and the ailerons are rigged for neutral. I also drilled the holes in the wingtip to mount the wingtip lights.

An issue I had when I first worked on installing the engine was routing the coolant hoses to the cylinders. In order to clear the engine mount RANS has you exchange two hoses for a hose with an S bend. On the left side RANS instructions worked great, which are to install the S bend hos from the lower coolant pump fitting to the aft cylinder. On the right side, there wasn’t enough clearance. By making the S bend hose go from the lower coolant pump fitting to the forward cylinder, I was able to get decent clearance from the engine mount. I then final installed the bolts that hold the engine onto the engine mount.

I hope the wiring will be really done soon. I want to be finished. This coming weekend I will be installing the wings and checking a big box off. I’m excited to finally get them out of the wing stand. Today I finished assembling the lift struts and getting everything ready to mount the wings. Another upcoming task is routing the heater hoses from the heater to the engine coolant hoses on the forward side of the firewall. This has been a puzzle mainly because I’m trying to use 1/2″ hoses everywhere when it seems 5/8″ hose is much more common. It will be possible, but it’s just taking a little more time.

Stay tuned for more in Ryan’s quest to have a flying airplane!

(80 h)

Mad dash to the finish

By Ryan

On September 5, 2018

In S-20

The summer for students has come to an end and I’m back in Iowa. Summer job was fun, I learned a lot, and met some great people. Alas, it is now time for airplane building once again. A lot happened since the last update in March, so I’ll try to cover all of it.

I made a crazy work week before leaving for Denver in May to get a lot of stuff done. I accomplsihed most of what I wanted to do. I mounted the ailerons/flaps, fitted up the windshield, completed the second seat (that had been waiting since Thanksgiving of 2016), and prepped the hangar in case I got a hangar spot closer to home. The last bit did happen which was great. The plane now resides a mere 15 minutes from home compared to the 55 minutes it was for the last year. Still not quite as good as just being in the garage, but it’s too big now anyways. This should allow me to get a lot done on the plane these next 4-6 months (or until I convince someone to give me a job 🙂 ). I only have one class to finish up my fancy-pants degree and I will be doing some flight instruction, but I should be able to go full airplane build mode for most of the time.

The second great news is that we finally committed to finish the project and have purchased the avionics and the engine. The plane will use a Rotax 912ULS (100HP) engine. I started to become nervous about this before the decision since there was and still may be a chance we will move to higher elevations. The Rotax 914 would be the safest bet and make an awesome airplane, but in the end I couldn’t find any reason at this point in our lives to drop another $11k-13k on an engine to get a turbocharger. Maybe the next plane or when this 912 gives up.

The avionics are pretty bare bones. I’ll go into more depth when I get to wiring stuff, but I’ll have a Garmin G5 for primary flight information, a Appareo ESG transponder (RST Engineering has a great deal for EAA/AOPA), a Garming GTR200 radio, and my homegrown engine monitor (also looking at purchasing something from MGL as a backup and to reduce the risk that my engine monitor doesn’t want to work; I don’t want to delay flight testing for an engine monitor). The wingtip lights are the AeroLEDs Pulsar NSP variety. The other big (maybe controversial) decision was to forgo circuit breakers for most of the electronics. I will be using fuses for all of the equipment in the plane and then circuit breakers for the master and generator circuits. With my desire to fiddle with electronics, I couldn’t devise a plan that would let me hack the electrical system as easy as having banks of fuses with available slots. More to come as I get into wiring.

As I get further into the build, I find I have less and less to say about the specific tasks I’m doing. I wish I had more to say to help others, but I have been putting off writing these for too long after doing the tasks. I hope to change that moving forward.

One thing I will say about the boot cowl sides. For us tailwheel builders, you have a choice. You can either install the boot cowl sides with the gear off or you can trim the boot cowl sides to go around the gear blocks. I did the latter and ended up trimming off too much of the boot cowl and now I have a gap. I plan on getting some thin aluminum to extend the area I trimmed and make it a more flush finish with the fuselage. So if you’re tailwheel and don’t want to remove the gear to install the boot cowl, go very slow and check often. I think it would have gone better with another person to help me hold the boot cowl up and check interference. With only two hands, it gets difficult to check and trim quickly.

Some other small items being completed are on the firewall. This includes the battery box build up, and mounting the coolant overflow bottle. I had a very annoying spat with some stainless steel rivets on the battery box. The stem would pull completely out of the rivet on most of my attempts. I took a break, ordered some more rivets, and used some rivet backing washers. That solved the issue. Not sure what was wrong, but my casual internet reading (very dangerous) leads me to believe it may have been the rivets themselves, but I don’t know enough to say how much belief to put into that thought.

In general shop news, after 3.5 years of building I finally bought some shelves and a work table to supplement a small workbench. Not sure why I didn’t do it sooner, but I was younger then 🙂

The panel is off to the laser cutter in town and some more orders to Spruce and Digikey are inbound. I’ve attached a picture of the cutouts I’m making for the panel. Hopefully it works well. I think I could do much better from a human factors stand point, but we shall find out when it is flying.

I’ve been adding to this for a few weeks, so I’m pushing it out and I’ll be getting some more updates in the coming few days.