takair

I’ve done some testing on this and have video buried somewhere in the forum. The old retractable step has lots of un-aerodynamic surface area as compared to a fixed step, so there is a lot more drag. You have to be very patient to measure the speed, but I’ve measured from 2 to 4 kt reduction, depending on how hard you want to push the plane. The greater speed loss is not entirely from the step, but because the plane is out of trim. In fact, a good hint that the step is down is that the ball will be out of center. Rest your foot on the rudder and you will regain about two knots. You could of course rig the plane to compensate, but you will still lose about 2 knots. Keep in mind that it takes multiple minutes and stable air to measure this….it is not near as dramatic as speed brakes. As a side note, that same drag puts lots of preload on the step in flight. I would not encourage moving the step in flight, at speed, as it can prevent smooth movement and loads up the actuator and mechanism.

Hi GoodyFAB. I see you are out of 42B, but is the picture of your plane at BDR? I currently keep my plane there. A friend who spends some time on the forum here sometimes uses Henry Webber’s, in PA. You may check with them. There used to be a few others in CT who were familiar, but I’ve kind of lost track of them.

I find that when taxing on bumpy grass or pavement and the nose starts bouncing, a healthy dose of up elevator softens the oscillations. Maybe it’s in my head, but I still do it routinely, even at my paved home airport, where there are some aggravating bumps. On grass I tend to taxi with up elevator to prevent the oscillations from starting, between that and just the right amount of power, it seems like it keeps things in check. Short body E. Perhaps the short airplanes with heavy engine are more likely to respond?

No deposits yet, but the FAA finally responded to me on the updated Auto-Lean data package. Of course, it means more work and more documentation….but some progress for quadrant equipped aircraft.

In the scenario you describe, it would almost certainly have to come from the manufacturer of the autopilot. This is because it is difficult to put an STC on top of someone else’s STC. It is ok on a non-interference basis, but this specifically would break that rule. My philosophy and cert basis for Auto-Lean, was that it mimics what the pilot would do to lean the engine in accordance with the flight manual. We also used analogue and mechanical safety systems to reduce the cost of software certification. This was effective in keeping the cost down, but limits some levels of authority. The auto throttle that I prototyped was based on the Auto-Lean system. The first iteration was for fixed pitch propellers to manage RPM…sort of creating a constant speed prop. The next iteration would manage power based on airspeed, RPM and manifold pressure. This would effectively provide airspeed hold. The key is to perform this function without getting the pilot or autopilot into oscillation. Communication with the autopilot would certainly enhance this, but would require OEM cooperation. As I recall, the retrofit FADEC that I mentioned was running at over $25k ten years ago. I suspect the system you described would be that or more; given todays (lack of) market, certification costs and liability. Even the system I described, call it a partial-authorityDEC would likely be about $10k. The survey results to this point generally follow my experience after over 10 years of Auto-Lean. Even then, I think some people might wait a lifetime for the system to be proven. The fact is, there are and have been proven systems….but then I suspect price point would be the next reason for not buying. I suspect that results might be slightly different if you were to poll folks buying new aircraft that came only with FADEC…think diesel aircraft.

They are a pain. The key is to go slow from one end to the other and slowly stretch the material over the cup flange. It may pop off until it hits just the right amount of stretch…so don’t give up if the first three times don’t work.

Our current iteration of Auto-Lean has been STCd for about 8 years. It is approved for dozens of GA aircraft. We currently have a cert plan with the FAA to expand it to quadrant equipped aircraft and provide other enhancements. This has been a slow process in the post COVID FAA, I can’t explain why. That said, the current iteration provides multiple features, including LOP, ROP and HOLD. It is based on a single EGT probe input. I have used iterations of it for over 10 years and now use it routinely in conjunction with the SureFly ignition system. I find it to provide workload reduction and fewer distractions. Our original roadmap was to expand to multi cylinder EGT and then RPM and MAP. The individual parts have been prototyped. We have also explored O2 sensing as well as knock detection. However, the intent was to fund the development and certification using sales of the basic Auto-Lean system. Unfortunately, sales have not been robust, and an advanced model would simply add cost without any indication of a larger market. As a parting story, when I was certifying Auto-Lean I met a gentleman who had developed a GA FADEC and eventually sold the company to one of the big OEMs after his own sales were not good. He warned me that he found the FADEC market rather soft. I suggested my system would be a fraction of the cost….but he was still sceptical about the market. If I recall correctly, that product is no longer offered to the aftermarket and his premonition was correct. It would be interesting to understand what people define as FADEC and how much they would be willing to pay for the product and installation? What features are desired and what are those features worth?

I like to think that with Auto-Lean and SureFly I come pretty close to having FADEC. The market would need to indicate demand for more. There have been FADECs for the retrofit market, but not enough demand. For what it’s worth, we do have a prototype Auto-Throttle that we have bench tested….it works, it is doable….just need to know there are a lot of people who want it. Happy to discuss in detail via another thread, PM, phone, or email.

Can you tell us more about DIY nickel plating? I did some plating in college, but that’s as at an industrial scale.

I use this in my uninsulated and leaky hangar. On low it gets it warm enough to be tolerable on a 20deg day.

Great, another thing that’s “not quite right about the world”, to drive me crazy.

I can’t see a crack or anything in your picture. Clean with sandpaper/scotchbrite and add appropriate size hose and clamp with two loops of safety wire. Almost sure that’s how it came. The hose may get loose over time, but easy to get it to the leak rate of 100ft/min at 1000’. That is the goal for a Non-pressurized airplane. If pumped up to higher altitudes, that rate will appear large, but the rule is all you need to achieve. You can spend a lot of money getting an old airplane to zero leak rate and it won’t make any difference in operation.

Don’t know if I have that, will have to look, but I would suggest you contact Cecelia, at Brittain. She tends to respond and is good about getting paperwork to folks.

I think the RPMs they run at Reno validate the idea that there is more HP to be had, but the TBO…..if they make it there….might be as low as a race weekend. Also, the accessories are also a limiting factor, nylon gears in mags, vacuum pump vanes, alternators. I’m also not sure how the harmonic balancers and prop harmonics respond to RPM outside of their design limits?

But, isn’t the 10% only allowable for 3 seconds? They even call for logging < 5% and correcting it. I know this is in the noise of many tachs, but I don’t see this SB as giving much flexibility in setting the red line.

The line typically starts as a hard aluminum line at the #3 cylinder, converts to copper, through the firewall and converts to flex. They often chafe or crack near the cylinder…especially where it rounds the bend. The bleed hole is usually on the bottom of that line near the tap. In the short piece of video where I see MaP, it seems to move a little in rhythm with the surging. Question is, what comes first???

RM Just emailed a couple of things. What you need in addition is Brittain 402-021-519. Maybe someone has it electronically or you might want to call Cecelia at Brittain and I’m sure she can get it to you. If not, I can scan, but it takes some time so might take a few days to get to it. Edit….check email, you should have it all now.

Agree. It used to be up to the installer to determine. Sounds like Garmin may have added a layer of red tape.

It’s kind of hard to see the MAP in the video, but seems to be moving as well….I have seen the MaP lines chafe through or crack on the back side, hard to see, but they can introduce a leak as well…easy thing to check…. Also, be sure your fuel vents are clear….although it seems that would be worse with high power.

For what it’s worth, have been flying mine for over 25 years, 2 engines, and have not seen what you showed in the video. I think you are right to keep investigating.

Tom The FAA very much recommends that field approvals be submitted prior to starting the work. While I haven’t done one post COVID, and they are not like the old days, some FSDO’s work closely with the Certification Office on field approvals. The last package I did was as comprehensive as a one time STC, but they were cooperative. It included certification plan, approved flight manual supplement and ICaW. Unfortunately there are still inconsistencies between locations. I hope you are able to get this done.

Assuming Robert sent one, but if not, let me know…

If it has a Brittain, the airspeed has a calibrated leak. That said, I can’t imagine a static port has over a 100fpm leak at 1000’ setting unless it is cracked. They do get leaks if the tube is not well attached. As I recall, mooney used safety wire on older ones. For the OP, what is the leak rate your mechanic is trying to fix and why does he think the port is bad? How is he sealing the system to test it. I used to do these tests and folks can get over zealous in trying to achieve a zero leak rate. It is not required.

This is what I would personally call “on step”. If you don’t dive to get to cruise trim, you will eventually get there from level flight, but it takes longer. I haven’t run the numbers, but I suspect your overall leg time is longer when approaching trim speed from below or from level. To me getting on step is getting to trim speed faster. Thinking out loud, As others have alluded, on step likely comes from a nautical term. To me, when a boat or seaplane is “on step”, it is at its optimal trim configuration for the power available. It takes time and perhaps some work and perhaps trimming to get there. I do t think the term “on step” as used in aviation is a bad term if used to indicate “trimmed out at optimal speed”. You can and will get “on step” from target altitude or below, it just takes a lot longer. It is also easy to fall “off step”, when you have some sinking air….we’ve all experienced these conditions.

Probably fair to share that Dave and I worked on getting his altitude hold tuned. Great learning experience. When I set up your dynertial on my plane I was using about 150mph and up….so it was definitely optimized for a higher speed. This is likely why you have had to adjust the decay and may require additional adjustment if you typically fly at a lower speed. I think PT20J is correct about what is perceived as the “step”….it is really just getting to trim speed. If leveling right at or below target, a Mooney takes quite some time….multiple minutes to get to trim speed. The dynertial system can make it even more interesting since you need to anticipate its inputs too and the resultant trim might not be perfect every time. Someone above mentioned climbing above target and settling to target, this can reduce getting to trim speed faster…by multiple minutes. Another consideration is that when at a higher speed, one has more reserve energy. So, at 120mph, if you get below target altitude, it can take more pitch or more time to get back on target altitude. This might give that feeling of slower response as opposed to higher speeds where the reserve energy more rapidly gets you back on target altitude….basically trading airspeed for altitude. If you have more airspeed, you can convert it to altitude faster. The autopilot has similar constraints, but it has more limited knowledge and less things to help it come back to target. For example, when hand flying, you may fine tune the trim and power, but the dynertial only has its limited authority on the elevator, so it will behave slightly differently….especially since set up for a higher target speed.