Kit Aircraft Modifications

Good Morning,

I had my good friend John Goris from Purple Hill Aviation (www.purplehillair.com) over this morning to have a look at my RV-10. We were talking the other day about this wiring harness redo when I was out at his shop. John does all sorts of aircraft maintenance. He works on both certified and non-certified aircraft and has been a great resource to me as I trod along the path to completion of my RV-10 project.

John currently has a Cessna 337 in his shop which is being converted over to have new engines. The owner is installing turbocharged LS7 engines both front and back. It is quite a project. The guy wants to be able to fly it non-stop from Southern Ontario to Cuba. Canada does not have the same flight restrictions going into Cuba as the US does. The kicker here is that we can fly direct to Cuba no problem. We just cant land in the states on the way there!! It has to be a direct flight.

This guy holds the patent on the serpentine belt tensioner and manufactures them for all of the automakers. He has money to play. The 337 has a wing off of a variant used in Vietnam for spotting. The whole wing is a fuel tank practically and he has drop tanks installed on mount points on the wings as well.

Getting back to the wiring harness, John wanted to come over to see how I was progressing in the change over of wiring and to have a look see as to the overall progress I am making.

As an AME he totally agrees that there is a problem with the PVC coated copper wiring used in the OEM wiring harnesses used by alternative engine installers. He looked over my partially complete installation and gave me the thumbs up.

I received the special terminals for the injector connectors from Mouser yesterday an can now go into the garage to finish them up. Once that is complete I can move my Black&Decker workmate over beside the plane and start threading the myriad of wires through the main connectors that attach to the ECM. Once I have them all untangled and cut to the proper length I can get going on attaching the new terminals there.

I have been asked to write an article about this for our local RAA (Recreational Aircraft Association) and I have a feeling that It is going to end up in a couple of magazines like Sport Aviation and the Recreational Flyer. I have taken a bunch of pictures to accompany the article that I will get posted in here eventually.

Have a great Flight!

Dave

Hi Everyone,

I spent most of my free time on the weekend working on the engine wiring harness. After consulting with AC43-13 which is a manual that sets out acceptable methods and practices regarding aircraft construction and repair, I determined that the PVC coated copper wire used in the construction of the engine wiring harness did not meet the standard.

PVC or Poly Vinyl Chloride is the plastic material used to insulate most modern wire used in engine wiring harnesses. The PVC insulation used in engine wiring harness will burn and when it does it gives off a very toxic smoke. Not good if you are in an airplane. The melting point of PVC is around 175 deg F. or 80 deg. C. The conductor is stranded copper which has a propensity to corrode.

Ac 43-13 stipulates that wire manufactured to Specification ML-W-22759/16 be used in aircraft. It features stranded tin-plated copper conductor and is insulated with extruded Tefzel (ethylenefluorbethylene) which has a maximum temperature rating of 302 deg . or 150 deg C. It is also rated for 600 volts.

As you can see, there is a marked difference between the two types of wire. The heat rating is almost twice as high as the PVC and the tinned multi-stranded wire resists corrosion.

So here I was with a wiring harness that I purchased  from Painless Performance that fits the Delphi MEFI 4b ECM that doesn’t have the correct wire. What to do?

Well, I started off by going to talk to my friend who owns a car stereo and alarm installation business. He told me to go to an auto parts wholesale place around the corner and there I could buy all of the terminals I would need to replace the ones in all of the Delphi connectors.

This proved to be an interesting experience. The guy there pulled out a catalog full of about a million different connectors and terminals. I realized that I needed much more information before I went in there to order.

So I came home and looked at each individual connector on the harness I purchased and photographed them. I then took the photographs and the codes on the connectors in to match them to the photos in the catalog.

This worked out pretty well except for the terminals in the connectors that attach to the fuel injectors. These were only available from them as an assembly or pig-tail. This was no good for me as the terminals would have already been crimped and PVC wiring would have been included.

After a little digging and a couple of phone calls I ended up with the actual Delphi part number. With this in hand it was relatively easy to find the part on the internet. I purchased the terminals from Mouser and had them shipped.

For the wire, I went to Aircraft Spruce. They sold me about 500 feet of 18 gauge Tefzel wire in 4 colours for the project.

I was able to locate a pin-out list and diagram on-line through MSD. They sell a comparable computer.This gave me an understanding of all of the wire runs which allowed me to pull all of the pins from the  two 32 pin connectors that attach to the computer.

With this done I could then start to take the old wire out of the plastic connectors which I plan to re-use. I have been able to recreate the individual sensor harnesses and have laid them in place.

I will install the terminals to the wires going to the ECM connectors next.

All of the connections to the terminals that I have made so far have also been soldered at the very front of the wire. I only apply a small dab of solder at the very end of the wire so to keep the rest of the wire within the crimp flexible. Too much will take away the wire’s ability stay flexible. Failure to do so will lead to breakage due to vibration.

This was one of those unexpected jobs that pops up when you don’t expect it. I am glad that I was able to understand the specifications and install the proper wiring in my airplane. I would do it all over again as it is the proper way to do things. It just took a long time to run around and get all of the materials and more time yet actually installing it.

Have a nice flight,

Dave

Good Morning,

Today I am going to talk about the purpose and placement of the fuel regulator for my LS1 fuel supply system.

The LS1 engine I have mounted to my RV-10 requires a fuel supply system that supplies high pressure fuel to a fuel rail connected to the fuel injectors. This ensures a constant supply of 50-60psi fuel at the injector which is only used when the fuel injector is triggered by the ECM.

The fuel system also requires that the fuel flows through this fuel rail and eventually back to the supply tank. At some point in that circuit the pressure needs to be returned to atmospheric and this happens as it goes through the pressure regulator.

The fuel pressure regulator does the same job as your thumb when you put it on the end of an open garden hose. The spring in the regulator applies pressure to some sort of restrictive mechanism the same as you applying pressure to your thumb over the end of the hose. The result in both instances is a rise in pressure in the tube leading to the restriction. The fuel or water as in the hose example returns to atmospheric pressure as it is released through the smaller opening.

In my installation I have the fuel being supplied to the co-pilot side fuel rail where it flows forward on the engine. It gets bridged to the pilot’s side rail via a braided stainless steel flexible fuel line. It then runs aft and exits the fuel rail directly into a pressure regulator. The low pressure fuel is then routed back through the firewall and into the header tank. Any excess fuel is then routed back to the supply tank via the return tank selector valve.

The fuel pressure regulator has a 1/4″ barb fitting coming out of its upper housing that is attached to a vacuum fitting on the intake manifold. There is an adjustment nut on the top of the regulator to vary the pressure according to the engine’s needs.

I am thinking of installing a mechanical fuel pressure gauge in an unused port on the side of the gascolator at least temporarily. I would like to be able verify the actual pressure against the indication I receive from my engine monitor. It will also be useful if I need to adjust the pressure while the high pressure supply pumps are running.

Well, I have pretty much hit on everything I have done regarding the fuel system.

I am going to be working on and documenting the complete re-wiring of the engine wiring harness next.

Dave

Morning,

I am going to talk about fuel lines in the engine compartment and how important it is to have them properly routed and protected from heat sources.

My RV-10 has a fair amount of fuel line running throughout the engine compartment. Along with this line are some pretty significant sources of heat. I have given a great deal of thought to the placement an routing of the fuel lines.

This has been fueled (sorry!) by the knowledge of an incident involving another V8 powered aircraft that had a fuel line failure within the engine compartment. The aircraft was a Wheeler Express and there was very little time to get the aircraft on the ground.

Luckily there were only minor injuries to the two occupants but the aircraft landed in a hay field and was completely consumed by fire.

As a result of this, I have decided that all flexible fuel lines in the engine compartment shall be Teflon lined, braided stainless steel lines with proper aircraft grade AeroQuip fittings. Each line also is covered in high temperature fire sleeve that has had its ends dip sealed in liquid high temp silicone and the ends mechanically fixed with stainless steel band clamps.

I have lines running from  the firewall to a drain valve as mentioned in the header tank drain valve post. I have a line running from the gascolator to the fuel filter. Another, from the fuel filter to the right side fuel rail. A line runs between the fuel rails at the front of the engine and another runs from the fuel pressure regulator back to the firewall to drain into the header tank.

All of he lines have been routed away from the headers which are the primary concern when it comes to heat. I have also tried to make sure that there is adequate cooling air flow over the lines in an attempt to keep the fuel as cool as possible as it moves toward the fuel rails.

This is one area where you want to spend the money and buy the best that you can get. I have my hoses made by the same people who make the replacement hoses for the Air Canada Jazz. This feeder line has a local maintenance facility at the local airport.

Have fun in the shop today,

Dave

Hello Fellow Modifiers,

I would like to touch base on the importance of being able to check your fuel for water and foreign contamination.

As we all know you have to be vigilant when it comes to checking for water in our fuel systems. This has had an influence on the design of the header tank that is mounted on the cockpit side of the firewall in my RV-10.

I designed the tank such that there was a sloped reservoir at the bottom 2 inches of the cylinder that makes up the tank. The dual high pressure pumps draw fuel from bungs welded an inch or so up the side of the tank. The drain bung was welded on the small flat on the bottom.

This gives me a system where any contaminant has a place to settle below the bungs that supply fuel to the engine. The sloped bottom of the tank directs sediment towards the bung on the bottom.

I have installed an aluminum tube that goes from the drain fitting on the bottom of the tank to a bulkhead fitting at the firewall originally purposed as the fuel supply line to the Lycoming  IO-540. From there, a fire-sleeved braided steel hose attaches to a spring-loaded check valve at the bottom corner of the  firewall on the co-pilot side. I installed it beside the gascolator so that both could be covered by a single access door. This allows an easy check of the fuel system during your walk around.

I have to give Ross Farnham  the credit for most of the design of my fuel supply system. He is installing a twin turbo 6 cyl Subaru in his RV-10 and had already designed a similar system for his RV-6. I like to be able to draw on well proven ideas and installations such as he has.

I have also been working lately on building myself a couple of headsets. I like the in-ear units sold by Clarity Aloft but do not like their prices. I stumbled across some do-it-yourselfers  on the net that have built their own. I will chronicle my experience in building one of these headsets in a future installment.

Keep your wings level!

Dave

Hi Everyone,

Well the launch of this product sure has been an odyssey!

I have been working for about a year and a half in an effort to bring you a safe and reliable remote switch that you can remotely start the engine and cabin preheating process. The major stumbling block in this process has been in finding a reliable supplier of the control boards. I am happy to say that I have finally moved past this road block and that I have boards on their way to me.

The next step is one that one that I think is mandatory.  Electrical compliance testing for operation and fire safety. This unit is going to be controlling electrical heaters and it needs to be the strongest link in the chain. There is a similar offering that has recently been announced by AeroTherm.

Their device uses a board similar to the one I initially began prototyping with. I found that the output relays on the board as supplied were only rated to CE compliance. This does not meet the IEEE safety requirements for North America that a UL, CSA or TUV rating would provide and does not require the rigorous safety testing that these other ratings ensure. I also know that the board that their unit is based on is being phased out and is currently no longer in production.

When I receive the new boards in a few days I will have an updated design that allows for a greater functionality. The new design will be able to read inputs as well as be able to direct outputs. It will also be able to be directed from your computer. I have yet to see the operating and set-up instructions so I will have to get back to you on that.

I appreciate your patience and that of all of the people who have contacted me regarding the availability of this product. If all runs smoothly with this new board I will have units available for sale by Christmas.

Thanks again,

Dave

Good Morning,

Today I am going to talk about how fuel flow is measured when you install an engine that uses a circuit type fuel system. By saying circuit type I am describing a system that supplies fuel to a pressurized fuel rail then sends unused fuel back to the supply tank after going through a pressure regulator.

In my RV-10, I have low pressure Facet pumps that supply fuel to a header tank. From this header tank the fuel gravity feeds to the high pressure pumps. The high pressure pumps supply the engine fuel rail and the unused fuel is depressurized and sent back to the header tank.

The header tank has an overflow fitting at the top which directs the unused fuel back to the supply tank via the return fuel tank selector valve.

So now we have to be able to accurately determine how much fuel is actually being consumed by the engine.

I approached this by looking at the low pressure side only. I placed the supply  fuel transducer after the fuel supply tank selector valve and before the Facet low pressure fuel pumps. The distance between these two connection points was fairly long which was recommended by the transducer manufacturer. I have the little red cubes.

I then placed the return fuel flow transducer in the header tank over flow line between the tank and the fuel return tank selector valve. Advanced Flight Systems supplied me with a little box that both the flow transducers plug into. The box electronically resolves between the supply and return flows to give an accurate usage.

Both of the fuel transducers were mounted on pieces of aluminum angle and then mounted to the inside of the centre tunnel at a 45 degree angle. They were mounted at an angle to assist any possible fuel vapor bubble in moving past them.

Tomorrow I will discuss the importance of the drain valve in the header tank.

Keep pounding those rivets!

Dave

Good Morning All,

This morning I am going to continue with the articles on the fuel system development. My last article on this subject regarded the gascolator  placement.

Today, I will go through the decision process and design of the fuel valve(s).

In my RV-10 there are the usual two wing tanks as well as an auxiliary tank that I placed in the baggage compartment. This results in three feed lines running to an Andair fuel selector valve mounted to the top of the centre tunnel between the two front seats.

The tricky part of the whole affair though is the fact that Andair doesn’t make a duplex style valve for three tanks. I would have been able to get away with one valve had I not added the auxiliary fuel tank in the baggage compartment.

The fuel system for the LS1 engine requires that the fuel run in a continuous loop with unused fuel from the fuel rails being directed back to the originating fuel tank.

After a few phone calls and pondering how I might get the giant octopus of a triple tank duplex valve in the narrow centre tunnel anyway, I decided on putting dual ordinary simplex valves in place of a more complex duplex valve.

This adds some complexity and unorthodoxy to the operation of the fuel system but in the end, I think that it is not so foreign that it cannot be incorporated into standard cockpit operating procedures.

In essence, the two identical fuel valve handles will always have to be placed in the same orientation. Each handle will be identified. One being supply and the other being return.

I have them both located along the longitudinal axis of the plane and they fall to your  hand on the top of the centre tunnel.

Installation of the fuel piping was actually made easier because of the two locations and in all it made for a very neat installation.

Here is a picture of the two valves as installed.

In the next segment I will talk about the location and installation of the fuel flow transducers.

Have a great flight!

Dave

Hi Everyone,

I bet you all thought that I have fallen off the edge of the Earth! I am sorry that I have not posted in almost a year. That is hard to believe! I have been messing about with a couple of business ideas as of late and between that and my family commitments I have let this blog fall off my radar.

In this post I am going to give you an update as to where I am in the process of building my RV-10 as well as fill you in on the LS1 installation progress.

Today, I cut a huge hole in a perfectly good and completed fuel tank. I needed to do this so that I could gain access to the back side of the inner most rib of the fuel tank. the fuel system for the LS1 requires a return line to the fuel tank so I needed to install a bulkhead fitting in the inner rib.

I purchased a spare set of inner tank ribs a while ago in an anticipation of doing this job.  To gain access to the tank I cut out the middle of the embossed lightening hole. The centre is not punched out of the tank ribs for obvious reasons. I took the largest hole saw I have which is about 3 inches in diameter and cut a hole in the middle of the area I wanted to remove. I then took a smaller hole saw and went around the edge of this circle making holes that went out to the outline I drew on the rib before hand.

I trimmed out as much of the waste material as possible with tin snips and removed the rest of it with a die grinder. Then I filed the hole out to the marked line and sanded the edges and the front of the rib outwards from the hole about an inch.

I took the purchased rib and cut out the whole embossment about 1/2 inch larger than the raised portion. This gives me a lot of surface area for the ProSeal to bight into. This part will be the cover for the hole I made to gain access to the inside of the tank.

I then found a flat spot close to the large hole and drilled a 1/2 inch hole. This is undersized to the fitting which is just under 9/16 of an inch. I then filed out the hole until the fitting just fit through. I did this because I am using an Earls gasket on the outside under the hex head of the bulkhead fitting. This will give me a good outside seal. Inside, I installed the washer and nut to secure the fitting.

Time to mix up the ProSeal. I slathered it all over the washer and nut and onto the inner side of the inner tank rib. This gives an effective double seal of the fitting. I then buttered the ProSeal onto the outer edge of the hole and outboard till I hit the line I drew outlining the cover plate. The cover plate went on after it had been roughed by sand paper and a thorough inspection of the tank was completed. I needed to remove a large amount of drill filings from the inside which was somewhat difficult due to the fact that the ProSeal in the tanks stays somewhat tacky. I had to use a tooth brush to get them out to where the vacuum would pick them up.

After installing the cover and pushing on it until ProSeal oozed out from behind, I applied another layer over the exposed joint effectively giving it a double seal. I had some mixed ProSeal left over so I installed the Andair locking gas cap latch ring in original opening. These caps are beautiful and with the price of fuel they have become a necessity.

My friend Charlie came over this morning and we loaded the wing I completed yesterday onto my trailer and took it to my our hangar for safe keeping. Previous to this I had been storing them in the basement. Another check mark in the long list that is building your own airplane.

The RV-10 has been making steady progress as of late with the lower cowl modifications almost complete and the muffler/header modifications nearing completion. I am planning to have it completed sometime in March or April.

I have been impressed and humbled with the statistics from this blog. I have been consistently getting 5000+ visits per month and this is in spite of my noticeable lack of posting over the past year. I have a whole sheet of bullet points that I need to touch on as well as my daily stuff to post so I have a lot of catching up to do.

Let’s see if I can get something posted a couple of times a week from now on. I would love to hear back from my readers in the future and would like to thank the ones who have posted comments and waited months to hear back from me. I will do better and will try to provide some good information on modifications to any kit aircraft that you may have.

This could be a very informative site for those who choose  to stray from the plans.

See you soon.

Dave

Hello Everyone,

I have been working on the cooling system over the last few weeks and we have made some solid progress. This is probably one of the most important check off items on the road to installing a liquid cooled engine in my RV-10.

Since I last posted we have had an engine test stand constructed and have the engine mounted in it. This is going to serve a couple of purposes. One is the ability to transport the engine to outside shops where work can be performed on it. This means that work can go on in my absence and as I am working 6 days a week right now in my day job it is a tremendous help in keeping the project moving along.

The first thing that needed to be looked at in the cooling system design was the failure analysis of the system as it was designed in the automobile. I did an engine to engine risk comparison looking at specific systems and more specifically sub-systems. In the cooling system as well as the electrical system the serpentine belt was a single point failure mode that needed to be addressed.

To address the failure mode of the single belt it was determined that a dual electric water pump system would be developed. This would be an either/or system where the secondary pump would be switched on if the primary pump failed. Failure of the pump could be gauged through current monitoring or temperature monitoring of the engine. The pump usage would also be alternated to make sure that the secondary would perform when called upon.

After much head scratching and conversation with GM engineers as well as the people from the aftermarket water pump manufacturer it was  determined that the dual electric pumps would be mounted to a manifold that has internal flapper valves to restrict recirculation of coolant when one pump is running.

This manifold has been built and we are now fabricating the mounting brackets for it. It will be mounted low on the firewall on the pilot’s side of the engine compartment.

In conjunction with this dual pump/manifold system we had a good long look at the old pump to make sure that we totally understood its functions before making the decision to remove it. The first thought was that we would remove it and replace it with fittings that attached directly to the engine block.

The more we dug into the pumps functions the more we found that it wasn’t so easily eliminated. The pump performs a number of functions. Temperature regulation via the thermostat,  coolant recirculation to help the engine get to temperature quickly and distribution of coolant to the cabin heat exchanger.

We would have had trouble maintaining these functions if we had removed the OEM water pump so we decided to modify the pump instead. We have removed the impeller and pulley from the water pump housing and by machining entrance and exit ports have converted the water pump into a coolant distribution manifold that retains the functions of the manifold portion of the pump while removiing the actual pumping of the coolant to a remote location where the twin pumps can be mounted.

All of this had to be researched and a plan put together before any effort was put toward fabrication of the actual cooling system components. Fabrication is the easy part! Luckily I have some top notch people working on this system for me and now that the majority of the engineering is out of the way I hope to have the engine back and available for the next chapter in this firewall forward development effort which is getting the dual custom engine management computer system designed, manufactured and tested.

I’ll talk to  you later.

Dave