Jump to content

Anticept

Members
  • Content count

    3,172
  • Joined

  • Last visited

  • Days Won

    4

About Anticept

  • Rank
    What's that red blinking light for?
  • Birthday 10/25/1986

Profile Information

  • Gender
    Male
  • Location
    Columbus, Ohio
  • Interests
    Flying and fixing

Recent Profile Visitors

15,319 profile views
  1. You can't fill the oil filter like they used to due to a change in the filter design. You should follow the procedure of rotating the crankshaft 20 turns though (50 rotations of the prop if you have a ULS), which will prefill the filter and purge air from the system. Rotax's tappets are sensitive to air, and can in rare cases, lock up briefly and cause something to bend. Then start up. Anyways, if you get a little warm on takeoff, just shallow your climb some so you get some forward airspeed. Pretty much every airplane out there can't take really hot weather in a hard climb and the extra speed will increase airflow in the engine compartment.
  2. So long Flight Design......

    It's called a CTHL (as according to the brochures), and it doesn't just have larger wing area, but also a larger stabilator. It uses a wing design more like the old CT2K. The CTSW is called the short wing because it reduced the wing area over the CT2K, and the LS lengthens the boom. The HL is no longer listed on flightdesign.com, so unfortunately I can't provide the specs and brochure that talked about it. I know, pictures of it shows "CTLS HL" on the tail, but that's the only place I've seen it called the "CTLSHL"
  3. Let's talk about grounds. Again.

    Retracting my earlier statement about the amperage flowing across the engine ground. I have remembered that rotax's alternator uses two wires on the charging circuit to the regulator. That means the regulator's ground is the critical component, not the engine ground, and it is usually directly jumpered to the ground bus in the aircraft. Engine ground is still needed for the sensors on it though, and the ground loop problem still applies, generating interference. Especially since there are ignition events going on, those will generate a LOT of interference in a ground loop in the right circumstances due to the extremely high RFI. Unsure if they will affect this particular configuration though. It's still possible to put a lot of amperage across that 22 gauge, if the ground between the bus and the starter is broken, the new path is: ground bus -> ems ground connections -> engine -> back to the starter. HIGHLY unlikely though because this wire isn't subject to vibration. However, it's still an extra path to ground, and there will still be some power flow across it, dropping voltage.
  4. Let's talk about grounds. Again.

    My illustration was just focused on the extra ground and where it was wired. Depending on the model year, the engine ground will go from the base of the alternator case, to the engine mount. A new wire from the engine mount will go to the starter solenoid case. From there, to the battery. There is also a wire that goes to the bolt from the solenoid case to the grounding block mounted on the firewall, that everything inside attaches to. One other thing i do recommend is tho move all the grounds on the starter case to one side. The starter case should not be used as a ground conductor. Terminal rings should either be grounded to a terminal block designed for it, or placed on a single post against one another.
  5. Let's talk about grounds. Again.

    Everywhere that uses the ground symbol: means its connected to a common ground (be it a ground plane, a terminal bus, or a string of jumper wires). We don't have to always use this symbol, we can also draw the grounds out. I didn't want to distract people with the irrelevant grounds, which is why I did not draw them, instead using that symbol, and drew the single important ground from a "-" connection on the EMS. The battery is at the bottom. I drew a box around it to help the reader understand that is the unit. Battery symbol:
  6. Bringing an old plane back to life.

    All you need is the data plate! You can build the rest around it!
  7. Partnerships - how did you do it?

    Big tip: If you do a partnership, it's usually simplest to require unanimous decisions to make changes to the operating agreement. That means where it's going to be based, who is going to maintain, how you are going to deal with someone who cannot pay their share, alterations, etc. Partnerships lower barrier to entry, but increase complexity of management. I got out of a partnership last year that cost me a lot more than It should have. I was inexperienced when I signed it.
  8. Let's talk about grounds. But first, a story to put into context why understanding what grounds are, and how they affect aircraft systems, to understand why this is so important. I have a 08 CTLS in my shop that I've been fighting with for a while now. Dynon D-120 EMS has an issue where both EGTs, both CHTs, and the oil temp fluctuate rapidly. However, it would never happen on the ground for me to test for. If I can't test for it, I can't fix it unless you just want me to throw parts at the problem, and even then it's not a guarantee. Still though, I did the typical thing, checked grounds. I put an amp on the wire to ground on the EMS connector and checked for voltage drop to the battery. Hmmmmm, got a little over a tenth of a volt. I disconnected grounds, and noticed something. Something that didn't click before. The grounding block inside the aircraft mushroom is freaking anodized aluminium. What. I mean really. Anodized aluminum must be sanded at the contact points to get a good connection. Removed the bolt that goes through the firewall, and nope. Not sanded. Really??? So, I take every ring terminal, bolt, and grounding connection from the EMS to the battery and clean them up with a wire brush on a Dremel. I then apply a little DC-4 to prevent oxidation in the future (including to the sanded aluminium block). Clamp everything down, and now the resistance has gone down to about a third of an ohm, and it translated into about 10 millivolts. A lot better! Still would prefer less, but that's acceptable enough. Reassemble, start up aircraft.... everything seems fine. Released to service. It comes right back with the problem again after about 20 minutes in flight. Alright you know what? Let's go fly so I can see what exactly the issue is. So I grab my little USB data logger, plug it into the cigarette lighter to monitor the power bus, and off we go Sure enough about 20-30 minutes, the whole panel starts going crazy. Both EGTs, both CHTs, and Oil Temp all fluctuating wildly. Come back, fully expecting it to be a regulator issue. Download the data from the logger, and it's relatively stable. What. I've never seen anything like this. What I figure is something is overheating inside the EMS unit. I need to determine though. I make a diagnostic harness. 111 solder joints, 37 crimps, and 148 shrink tubes. Basically it's a male to female connector with a third female connector pigtailed off it, so that I can insert pins with my meter and get live readouts. I do a ground run and start probing the readouts, everything looks good... wait no it doesn't. The panel starts going crazy. I hook into various pins and can't make heads or tails, everything is going wild. I call up Dynon, and tell them all I did, and they say "Alright... that's everything we would have suggested, send it in." Before I do though, I have another EMS unit I could hook up real quick just to see what happens. After a few minutes, it too goes wild. Welp, not the EMS. Oh. GREAT. What in the hell could be so wrong that it causes all kinds of problems across multiple pins? I even checked voltage drop to battery through my diagnostic harness, it's swinging from as little as a few millivolts to as high as a decivolt. Quick check of resistance on the harness... 0 ohms. So there's something real screwy going on. So I cut loose every piece of tape on the installed harness from firewall to EMS, and start checking for shorts or something to explain what is going on. Nothing. Nothing at all. Alright. I'm not going to go tearing apart every single harness in this aircraft yet. Let's see if there's some weird ground oddity. So I pull all the connections from that grounding block and hit the master. The EMS still turns on. I take a closer look at that grounding pin. HUH? There's a wire splice a little ways back. Where's this going? I follow the little 22 gauge. It goes to that grounding block. Mental note: replace that with 14 guage later. 22 is not large enough for a trouble free ground. The other wire is... a 14 gauge? Where's this going? Through the firewall. So I find the wire on the other side.... it's going through the fire sleeve. OH GOD DON'T TELL ME. It was bolted to the engine intake on the right side. WHO DOES THIS S***? So what's wrong with this? Lets talk about grounding. Grounding doesn't just provide a return path for power. It also serves as the electronic reference of 0 volts. This is CRITICAL. So critical, that the National Electric Code dedicates a HUGE ARTICLE in the code just to grounding. It's probably the LARGEST article in the whole codebook. It's CRITICAL. (mind you, their grounding is a little different because they dedicate a wire to just grounding, while we combine our ground/return into one for weight concerns) Everything electrical is primarily driven by the difference in electrical potential. There's a few oddballs like inductors and radio, but let's not go there. So when you have a 12 volt system, if ground is not effectively 0 volts, then you don't actually have a 12 volt system as far as your systems are concerned. When you do grounding, it's incredibly critical that you bond systems in a way that: Provides the least resistance to ground while under load. Just tossing your voltmeter on it isn't enough. Resistance drops more voltage as more amperage flows, which causes your power differential to go down. Those milli-amps your multi-meter are pumping won't detect a dirty ground, you need to put a heavy load on it and do a voltage drop check. That's also why grounds should be HUGE; much larger than what is typically called for for normal current carrying. The grounds should be branching, with no loops. Loops can pick up stray electromagnetic fields, converting them to voltage and current that go round and round the loop, and screw with the potentials and voltage drop. This is called a ground loop, and creates a lot of interference. Do NOT provide alternate grounding paths without sizing the wire to the maximum potential current they could experience. THIS IS A FIRE HAZARD. It's also easy to do without realizing what you are doing. If you follow rule 2, you won't have this problem. Do not provide ground paths that could back feed to systems and generate interference. This little extra wire violated rules 2, 3, and 4. Basically, by attaching a wire to the ground block inside the aircraft, and a junction to the engine block, an alternate ground path has been provided, that in extremely unlikely circumstances, can provide a new path to the battery and burn up the 22 gauge wire. In addition: if any grounds get dirty, it would cause a huge amount of interference on the EMS. Remember: electricity follows all paths, but favors the one of least resistance. As the ground gets dirty, more and more power will be shunted through that alternate ground. This will raise the potential on that ground via voltage drop. Now we know the alternators on our aircraft are not a smooth output. They fluctuate badly, by design (most are designed this way). That means every single on-off pulse is a voltage spike to EMS ground. I cleaned this up, and no more fluctuating gauges yet, as well as a hazard eliminated. Now, I know that there are those that advocate adding an extra wire from the engine to the battery. I've said before that I don't like it, but because the sizing is supposed to be large enough to handle the current it may experience, and both effectively terminate at pretty much the same point, I find it acceptable. My personal preference is that I would rather people increase the wire size of the original engine ground and terminate it on a terminal block as close to the battery as reasonable, and branch out from there. That's how it should be. If you stick to branching grounds without creating loops, rules 3 and 4 are not needed.
  9. Hobbs vs Tach time

    I echo the same feeling. Maintain to hobbs. But I still reiterate that you can still track TIS by tach or, most preferable, flight timer.
  10. ADS-B Installation

    A portable unit cannot transmit period. The FAA will bury them. https://www.faa.gov/nextgen/equipadsb/faq/#q8 If the FAA doesn't have legal recourse yet, they will soon I'm sure.
  11. Stabilator bracket crack

    Welding by nature is stronger than the original material, if done correctly. By itself, it meets the repair requirement of "restore to original or better condition". Be careful about strengthening without considering any potential issues that could arise though. The experimental homebuilt world is littered with wreckage from people strengthening areas without solving the causes or considering where those stresses will now go.
  12. ADS-B Installation

    I'm an A&P (so I know how to read ADs), and subscribed to the FAA AD mailing list for certain models of aircraft. (https://public.govdelivery.com/accounts/USFAARGL/subscriber/new?pop=t). https://www.faasafety.gov also has mailing lists that are very useful. What caught my attention on this was the fact that the AD applies fleet wide, so it hit on every airframe subscription I have. I've kept telling people that the FAA can issue ADs against ANY registered aircraft, engine, propeller, and appliance, no matter how it's certificated. If the airframe it's installed in has an airworthiness certificate, it's subject to ADs. So when someone says "I've got an S-LSA, I don't have to do ADs"... that's not correct. In addition, ADs are an amendment to 14 CFR 39, so they have really big, sharp legal teeth. Now there are procedures in place that the FAA must follow per the Administrative Procedures Act, as well as their charter and other acts of Congress. They can't just willy-nilly issue ADs, so you're not likely to see an AD that is applicable to your S-LSA or experimental. But they did this time with AD 2017-11-11, so it's kind of a big deal. If there's another fleet wide AD out there, I'm not aware of it. You can search for ADs here: https://www.faa.gov/regulations_policies/airworthiness_directives/
  13. ADS-B Installation

    Check the part numbers against the AD.
  14. ADS-B Installation

    The AD applies to all US registered aircraft, including LSA and experimental. It's in the AD text: http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/0/3156ea8fd766278486258137004ff683/$FILE/2017-11-11.pdf LSA is a category. Now that said, it doesn't mean your ADS-B package is invalid. The AD isn't prohibiting the use of NavWorx ADS-B units; it's prohibiting the use of the internal positioning system, which does not have integrity monitoring. Either the SIL level needs to be changed, or you must couple to an approved external GPS source.
  15. Rotax Radiator Cap

    It's critically important to get the right o-rings. O-rings in hardware stores are neoprene. They are only good at sealing water. Buna-nitrile (buna-n) or viton is what you want. Viton lasts a lot longer but doesn't seal very well at freezing temps (22 F or lower if I recall) because it gets stiff, and are expensive. Still, viton is best if possible.
×