Running the Engine (failure)

5.0 Hours

Today was going to be a superb day in that I expected to light the engine off for the first time. Unfortunately nothing is easy when you are building a plane, or it that just me ???? I have created a whole procedure to ensure I guard against any mishaps during the first start but first I had a couple task to do first. I wanted to get the engine pre-heated as it was a bit cool in the northeast last night and the plane is an unheated location. As I had installed a Tanis pre-heater this gave me the first opportunity to use it. A word of caution; the heating elements get very hot. As you see below I through a blanket over the engine but created space between the heating elements and the blanket with some old license plates I had. You can see where I located the plug to the heating system on the right.

Next I needed to prime the fuel system. I thought it should be pretty straightforward as the Rotax manuals say the pumps are self priming. As the wings are not on the plane I was using a jug with fuel in it and putting the fuel lines into that. The bottom line is I could not get it to prime. The pumps are working so I went back over the entire system making sure fuel lines from the wings through the first filter, through the fuel selector, through the gascolator, through the fuel pumps to the fuel regulator were are correct. I also went over the proper locations of the check valves and fuel pumps to ensure they are oriented properly. All good there. Everything checks out. Tried one pump then used both pumps at the same time and still nothing. I would not let the pumps run very long as I worry about hurting them. Before I started tearing everything apart I thought I should send an email to the Factory and see if there is anything I should be aware of. Lets see what they come back with…..

So that was a fail. I thought I would move onto installing the rubber weather stripping around the doors. I had purchased some two sided tape to accomplish that task.

That too was a bust as the tape would hardly stick to the rubber. I had cleaned the rubber with a very light wipe of alcohol.

Ugh. The day was proving to be a bust. One last try at accomplishing something which was the closeouts for the door hinge pins. That worked. One for three today.

Door Struts & Hinge Closeouts

3.0 Hours

I mounted the door struts that hold the doors open on the Sling 4. It was pretty straightforward though I hated to drill all those holes in the canopy to hold the lower mounting bracket. Below is a pic with some clecos holding one in position. I did that first to ensure the door would close all the way with it in that position. I had to release some air pressure in the strut to do that. I will show that farther down.

Here is a pic of the holes that are needed for the stainless rivets that are used to secure the lower bracket. I think I will fill/cover them with something to ensure no water leakage.

Here is another pic of of the lower mount in place.

The struts come with an allen wrench that you use on the grub screw to release pressure. It was pretty straight forward. I did numerous small releases until it was a “reasonable” amount of resistance. I may let off more but for the moment it will work.

I had these “L'” brackets that there were no instructions for but was able to figure out that they are part of the close out plates for the door hinges.

I painted the close out plates and then mounted the angels to the plates. The angles keep the screws that are the hinges from sliding out as there is no nut on them.

Today I hope to start the engine for the first time. I will do my best to document it but tend to get very focused and the camera gets forgotten. Lastly, when is it going to stop ??

Pilot Side Door Lock

3 Hours

Finally getting some time in the hangar These door locks continue to haunt me. The pilot side door handle was hitting the fuselage when I would move it to the open position. Can’t have that as it will mark up the paint. I took the door lock apart and sank the lock “boss” deeper into the door by grinding some more material away. I also noticed that the lock itself was slightly angled in a away that promoted the door handle hitting the fuselage. Using the Dremel I performed some surgery…..

After putting it back together and mounting the door back to the plane I have clearance. The below pic does not due it much justice as it is >1/4″.

I then started work on mounting the gas struts that hold the doors open. That will be next session. That and the rubber door seals.

The fuselage is looking much more complete with both doors on.

Back at it (Prop & Doors)…..

4.0 Hours

I have been away from the plane for a full month, not by choice. Covid went through the house, including me, and have to say that was a thoroughly miserable experience. I was bed ridden for a couple weeks and am still weak. I wish that experience on no one.

Anyway, today I got over to the ‘Hangar’ and started out replacing the bolts on the propeller flange that were too short. I had seen a post by Peter Calley that indicated he noticed the short bolts on his plane and I thought I better have a look at mine. Sure enough mine were short too. My understanding is that when the external alternator is mounted on the 914 you need the 45mm bolts, not the 40 mm bolts. This is what it looked like before. I cannot see a DAR liking the look of that and frankly I did no like it either.

I placed an order for M8 x 45mm that were grade 8.8. You can reuse the Norlock washers once so I did. The instructions are to lightly grease the washers when you reuse them. Below is what it looks like with the longer bolts in place….

Thank you for sharing your observation Peter….

Next I went back to the door locks. I needed to bend the rods that connects the front and rear latches as well as put roll pins in the rear latch connectors. Bending the rods was not that big of a deal though I did have to adjust length of the rod as the bend shortened the length. Just unscrewed the rod a couple twists.

Next I drove the roll pins in place. I had to purchase a few extra so they were long. I just cut them off with a Dremel then ground them smooth.

I thought it was time to mount the doors and see what needs to be done there. I put on the starboard side door first and after putting the AN3-20 bolts that are used as hinge pins I found the rear latch was dragging on the canopy and leaving a mark. I was able to get the door in place with out too much damage to the canopy by slightly twisting the door. Below is a pic of the rear latch in the open position seated against the canopy. I liked the way the “latch/hook” sat so as opposed to adjusting the rod further I trimmed off the tip of the latch. It only took an 1/8″ to get it to clear.

This is what it looked like after a slight modification.

I hung the port side door and found I had a similar issue though to an even lesser extent so shaved that one as well. What I did find was that the handle on the outside of the door was contacting the fuselage when it was twisted to the open position. On the starboard side door I think I had done some work to get the lock to seat deeper and think I will have to do the same on the port side. Ugh, more door work. The below pic shows what I mean. The highlighted tip drags on the outside of the fuselage in the open position.

Here is a pic of the starboard side. it clears nicely. Still need to add the weather stripping which may hold the door out some but I think it still needs some massaging.

Another item that Peter Calley pointed out was the need for a bushing on the inside of the end of the piston that holds the doors open. I totally see what you mean Peter…

I need to find someone with a 3D printer to make a couple bushings….

Next I need to figure out how to mount the studs the the door latches engage. Not sure how these plates come into play as they are not referenced in the instructions.

I also need to figure out where to put these handles. I think I will wait until the doors are mounted then see what I can reach with the door in the open position.

Below are a couple pics of the starboard side of the N77RL with the door hung. Nice.

Oil System Purge & Door Locks

4.0 Hours

I was able to get over to the ‘Hangar’ today. To be clear my ‘Hangar’ is just a two stall garage that my parents have. I am able to isolate and still get some things done. I have to say having a plane to build is a wonderful distraction from all the nonsense!

Today was a big day as I purged the oil system on the 914. I have been wanting to get it done for a while as I have had the engine for over a year and wanted to get oil back through it. It also means that I am close to starting it. I started out by adding coolant to the reservoir on top of the engine. I thought that as long as I was spinning the engine over I might as well get the coolant through the engine as well. I am a bit disturbed by the below pic as I have not had hair that long since my University days. Working at home can creep up on a person…

Next I connected the oil pressure regulator to the oil tank and put a short tub on the oil overflow tube that I pinched off with a spring clamp.

Then, per my last update, I pre-filled the oil cooler as well as the hose from the thermostat to the oil pump.

Next pulled a spark plug from each cylinder so I could spin the prop with ease. They recommend putting the plug back in the same hole it came from so I kept track of where each came from.

Last step was adding oil to the tank and bring the air pressure up. I used about 8 psi which is quite a bit less than the 15 psi max they say can be used. I left the pressure on a for a minute or two before spinning the prop. Below is a pic of Sabrina in the cockpit keeping an eye on the oil pressure for me, which she is pointing to. She called out the readings as it it came up.

At this point I forgot to take any more pics as I was kind of busy. I will say that it took probably 25 turns to get it up to 30+ pounds. Nice !! I connected th oil return line to the oil tank and then undid the turbo oil return at the oil tank. The instructions I read from Rotax said disconnect the hose and start the engine and look for oil to come out. Dean at Lockwood Aviation recommended that I use the starter to spin the engine and see if you get oil that way. The plugs were still out of the cylinders at this point so it would spin easily. Also there was no gas in the engine yet. The manual recommends pulling the ignition module connectors apart to ensure a start does not occur. I did not do this as I figured the factory should have run it dry. I don’t really trust others when it could cause great harm so I cleared the prop area, had the throttle at idle and was very cautious with the first bump. It was pretty exciting to see the prop spin via the starter for the first time!! I spun the starter for about six seconds and did not get any oil. I did it again for another seven seconds and got a nice stream of oil. I reconnected line to the oil tank. Next step it to start the engine, warm it up then shut it down and test the lifters to make sure they are hard. That will have to be next weekend.

Next I did a little more on the door locks. I found I was missing the steel inserts that go inside the brass bushing that are used as the posts on the fuselage the latches connect with. I was not about to wait on more parts from South Africa so ordered some tubing from Aircraft Spruce. Below is the brass bushing that the latch engages.

The steel tubing I ordered needed to be drilled out slightly to accommodate the M5 screws. That was easy. The outer diameter needed to be brought down a few thousandths as well so put the tubing in my drill and used some 120 sandpaper to bring it down.

Now I just need to cut out four 6mm sections.

It was a good day.

Rotax Log Book

0.0 Hours

As my house is locked down with two of the kids and the bride having Covid I had been doing a lot of reading and reviewing documents I have had for some time. Things like the Maintenance Manual, the Rotax 914 Operators Manual, the numerous videos on, etc. I also just glanced through the engine log book they provide with the engine.

A while back I had purchased a series of log books for the airframe, propellor and the engine so was not planning on using the log Rotax provided. As I glanced through it I saw they had actually filled the first page out which I thought was nice of them.

While nice it was not nearly as interesting as what I saw as I flipped through what I thought was an empty log book. There is a Service Bulletin section and in there was an entry that said that SB-914-055 that addresses replacing the circlips in the carbs was already done !! This really made my day as I was preparing to order the parts needed to address the SB. For those of you with new engines, if you have not done so already, have a look in your Rotax blog and see if there are any SB entries.

As I said that made my day yesterday then I wake up to this in the morning. Frame is twisted badly…… Life is a roller coaster.

Throttle Position Sensor and Oil Purge Prep

1.0 Hour

I only had a little time today do to too many non-plane obligations. I did get the Throttle Position Sensor re-programmed after I secured the throttle cable in the throttle quadrant. As a reminder the TPS is on the left carb so was focused on that one. I made sure that at full boost the throttle arm was up against the stop so I could be assured of full power. I reset both the idle location and the full boost location then pulled it back to max continuous power and the “Load” read 98%. That is within the +/- 3% Rotax says is allowable so left it there. I fully intend to look at it again after I sync up the carbs to see if it moved any of the settings.

I was hoping to purge the oil system today but with the twins down with the “Creepin’ crud” (Covid-19) so all I could do was prep for the big event. I emailed back and forth with Dean Vogle at Lockwood Aviation this week and he had some good insight into doing everything I could to get the oil moving as quickly as possible and purge all the air. After taking Dean’s Rotax classes last May I can say he has to be one of the most knowledgable Rotax individuals on the planet. When I was at Lockwood Aviation taking the class I had purchased the hose that is used to pressurize the oil tank to help push the oil through the system. See below for a pic of the hose used to pressurize the oil tank….

I removed the oil return line to the oil tank as that is where the pressure hose attaches.

Based on where the oil thermostat is located on the Sling 4 (right on top of the gear box) he suggested removing both the feed and return line to the oil cooler and pre-filling it and its associated lines.

In the below pic you will see I have removed the two lines on the forward side of the thermostat which leads to the cooler as well as one hose on the rear of the thermostat. That lines leads to the oil pump. Dean recommended as long as the that end of the hose was way up in air over the top of the pump to go ahead and pre-fill that line as well. I thought that all made sense. Now combine that with keeping the oil warm before purging and then pressurizing the oil tank I think I have a plan.

Lastly I used some compressed air to clear any debris around the spark plugs. You need to remove a plug from each cylinder as you will need to turn the prop by hand rather quickly until you get oil coming back through the oil return line and you get oil pressure on the screen. Based on that Sabrina goes in the cockpit while Wes and I spin the engine and watch for oil through the return line.

Door Locks and TCU Throttle Position

3.0 Hours

Seeing Peter Calley make such good progress on his door locks got me motivated to continue work on the left side door especially after talking with Jean at the Factory. I did not have a left turning door lock (I was provided two right hand turning ones) and had indicated that was a part I needed on the Sling Parts portal. After speaking with Jean about how to adjust throttle position for the max continuous power I mentioned teh left side door lock and he said he remembered filing off the tab on the door lock for the left side locks. Hmmm, I needed to look into that. Below is the tab that drops into a slot on the boss. It keeps movement to 90 degrees.

I figured I did not have anything to lose so filed the tab off.

I deepened the opening in the frame so that the boss set deeper in the door frame which would hold the outer latch off the window. That seemed to work well. Getting the roll pin into the hole can be challenging….

I filled he gap between the boss and the plate that covers the boss with a couple M3 washers.

After that it went together pretty easy.

I am still waiting on the left hand thread rod ends that attach to the rear latches in order to complete the door latches. With the doors stalled I moved to figuring out the Throttle Position Sensor issue I discussed in the last update. I received feedback from the South Africa Factory that it would have to be dealt with mechanically. In other words with the throttle cables. I had Sabrina in the cockpit moving the throttle while I was outside looking at the TLR software and adjusting the cable. I kept adjusting the cable and resetting the throttle position in teh software and was not making any progress. I could not figure out why. After about the sixth adjustment Sabrina says “Dad are these wire supposed look like this?” I jumped up and was taken back by the fact that the throttle wire to the left carb had pulled out of the compression bolt in the throttle quadrant. That was a little scary as I contemplated the potential issue if I had been in the air.

I cut off the frayed end (there was plenty extra) and put it back through the bolt (highlighted) and tightened it up. I double checked the right carb cable. That is all on me as I remember I was the one that installed those cables in the quadrant. Tomorrow I will give setting the throttle position sensor again.

I want to end this update recognizing the passing of a wonderful person and dear family friend. Fair winds Mr. Kirkendall…….

TCU Programming & Trim Motor

1.0 Hours

Got over to the hangar last night with the primary focus being programming the TCU for the throttle positions. As I have already mentioned you need to tell the TCU what is idle and what is wide-open. The hardest part of this whole procedure is making sure the laptop/cable setup will be able to communicate with the TCU. Since laptops no longer come with a 9 pin connectors you have to use a USB to 9 pin cable and that requires making sure the drivers download properly and that the computer is using Com port 1 or Com port 2. I was able to get that done (I hoped) and went over to do the deed. Below you see the TCU 9 pin connector. The pic is taken looking up from the floor on the engine side of the firewall.

I was able to connect first time. I really want to emphasize how much the Rotax Owner videos helped. The process is pretty straight forward once you have connectivity. I set the idle position and the wide open position on the program You then jump over to the monitor mode to verify the “Load” setting to make sure it is within the tolerances. Idle was great, wide-open was great then you bring the throttle back to 100% power to ensure it also reads 100% +/- 3%. Below you see I am at 108.5%. That is definitely outside specs.

I actually did the exercise twice to see if it would make a difference but got the same results. Before I just start messing around I thought I would email Jean to see the correct approach to making the adjustment as they had to have seen something like this before. Even with the identified issue I feel this was a success as I now know that I can get connectivity and can program the throttle positions.

I then moved onto to installing the trim motor. I installed it like this and then added the fitting to the end that attaches to the elevator trim piece.

Long story short I made some slight adjustments to the rod to get the trim tab even with the elevator and installed the cotter pins. Afterwards I brought home the Sling 4 Maintenance Manual and was looking for engine information and saw that there is guidance on the trim motor that gives some specifics regarding degrees of angle as well as the orientation of the pins that secure the pins to the trim tab and to the motor. It says the pin should point towards the fuselage. I have them reversed. It also says you cannot use the cotter pins more than once which make sense. What it means to me is that I need to get a few more cotter pins as I will need to reverse the orientation of those pins and to use new cotter pins when I do so. I have added it to my “to-do” list as I will not tackle that until the horizontal stab and elevator are on the plane.

Seats, Trim Motor & Rotax TCU Programming

4.0 Hours

Kind of a mish-mash of things on Sunday. Started off with securing the cushions to the seat pans. They are held on with Velcro. In the below pic you can see the white paper that peels off the Velcro. Under the paper is the glue that holds that side of the Velcro to the seat pan.

As the hangar is pretty cool this time of year I heated up the seat pan with my heat gun in hopes of getting the glue to secure better.

I had added my inflatable lumbar support bag under the co-pilot seat a while ago. That seat is still at the house as I have not added the outer seat rail to that side yet as my understanding is that it makes it more difficult to attach the wing. I did add the outer pilot side rail so I could make sure that I cut the sticks to the right length by sitting in the seat and getting a feel for what was right. Below is a pick of the adjustable lumbar support air bag I purchased through Aircraft Spruce.

I added a strip of Velcro to the middle of the bag to keep it from slipping down inside the seat.

One thing to share that I found through trial and error was to put the bag behind the foam and not just under the seat cover. Behind the foam results in a much broader “push” into your back.

Next I pulled out the Ray Allen trim motor I have had for a very long time. The unit for the Sling 4 is the T2-7A. Not sure if the TSi needs a stronger one.

The instructions are nice and clear but in my case as I have the G3x avionics you will not use the indicator light as those details show on the screen, The rocker switch will not be needed on my plane either as I put the flap control on the stick.

FYI while the instruction refer to a -6 mounting screw I was pleased that a M3 screw will work as well.

I wanted to test the unit and the instructions say a 9 volt battery will work well to move it and it did. To move it in or out you just reverse the polarity by swapping the grey and white wires. I moved it to half way extended and will mount the unit in the elevator then adjust the push rod to make the trim tab even with the elevator.

Every day has to have a “gotcha” and Sunday was no different. I thought I had a laptop with a 9-pin connector port but alas it is a different type of connector even though it is the same size and shape. The service port for the 914 TCU is a 9-pin connector. I mentioned before that you have to program the throttle setting. Since I do not have a laptop with a 9-pin port and laptops no longer come with them I found by watching Rotax-Owner videos that you can use a USB to 9 pin cable though it says many of those cables do not work as advertised. I purchased the one they recommended. I have already down loaded the TLR software but it seems you need to do some configuration in the laptop to get this cable to work. I will not go into the details at is clearly laid out in the video. I really want to get this programming done.

One thing to note is now that I have TCU power it appears the engine temps are now working.

Lastly a pic of the ride home from the hanger through the windshield. A quick 6″ of snow on top of the 14″ we received last week…… Gotta love New Hampshire !!