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FlyingMonkey

Adding AoA to a CTSW

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Hey all...

At the end of the Summer, I'm planning to Pull the wings on my 2007 CTSW (E-LSA) and replace the sight tubes, which are starting to get brown and less easy to read.  It occurs to me that while the wings are off, now might be a good time to enable the AoA function of the Dynon D100 I have in my cockpit.  I'd basically have to run a second pitot line alongside the current one from the pitot boom to the D100, and swap out the pitot boom itself for an AoA version (Dynon Part #10-02789).  I will probably have to bore out the pitot hole in the wing a bit to accept the larger diameter boom.  Total cost for all parts would be around $250 or less.

If anybody has done this or something similar, and knows of any issues or "gotchas" with doing this, I'd love to hear about it.  I do feel this is not a necessary upgrade, as I've never had any AoA or stall warning in my CT and never had any issue without it.  But it seems a pretty cheap and easy operation, and it's always annoyed me that the D100 has AoA built-in and I've never been able to use it.

I can also set the D100 to send audio alerts based on AoA (just beeping when you get close to critical AoA), I'm not sure if I will tackle making that work with the rest of the audio in the airplane.  I have a friend who used to be an Navy avionics tech on Hornets though, so he can probably set me up.   

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I don't do my own maintenance so excuse if a dumb question. Will wing removal for sight tube replacement and attachment point inspection give you the access you need to route a pitot tube through the wing?

Is there the possibility that you can fasten a double tube to the existing single and then pull it through without gaining access?

 

 

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The tubes have layups holding them in place in some areas. You'll have to run it quite a ways through all sorts of nooks and crannies.

As for the beeps: you have to make sure an audio wire is run from the EFIS to the intercomm. This wasn't done in many SWs.

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HI Andy,

It really isn't retrofittable. You have what you have for a pitot tube. You haven't crashed yet so why do you think you need one? If you have to hear alarms to know you are going to stall you've already made mistakes that should never have happened and evidently haven't happened.

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3 hours ago, Roger Lee said:

HI Andy,

It really isn't retrofittable. You have what you have for a pitot tube. You haven't crashed yet so why do you think you need one? If you have to hear alarms to know you are going to stall you've already made mistakes that should never have happened and evidently haven't happened.

Roger, like I said, not a "must have"...just an annoyance that the capability is there but not used.  If it's an enormous hassle I won't do it, but if it can be done with a few hours' work, then why not?

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14 minutes ago, Tom Baker said:

I would talk to John Hurst, or maybe call Lockwood. I know they have done one before. 

Thanks Tom!  I asked Lockwood about it when they did my very first annual 4 years ago, I can't remember why we didn't do it.  They either told me it was a huge amount of work and thus money, or it would take too much time (since I was staying at a hotel).  I'll call them and report back their response.

I don't know John Hurst, but I have CT friends who know him, so I can get his number.

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6 hours ago, Ed Cesnalis said:

I don't do my own maintenance so excuse if a dumb question. Will wing removal for sight tube replacement and attachment point inspection give you the access you need to route a pitot tube through the wing?

Is there the possibility that you can fasten a double tube to the existing single and then pull it through without gaining access?

 

 

Those are good questions I don't have answers to yet.  The "double pull through" you mentioned was what I was thinking as a last resort if I could not route a line by itself, but it's risky (if a line gets stuck or dropped halfway through you are f***ed) and if the original line is really laid up inside or tightly routed it won't work.

I also don't know about room and access.  Still just in the investigative stages of such a project.

 

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4 hours ago, Anticept said:

The tubes have layups holding them in place in some areas. You'll have to run it quite a ways through all sorts of nooks and crannies.

As for the beeps: you have to make sure an audio wire is run from the EFIS to the intercomm. This wasn't done in many SWs.

Thanks Corey.  I don't mind a long run, but I don't want to interfere with any controls or do anything crazy.  No "hillbilly engineering". :D 

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It's not that it would interfere... it's that this is a very difficult thing you are trying to do. It would be a project.

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Andy,

Still not available but that ilevil bom is supposed to be available soon. Maybe by oshkosh. Not only aoa but also pitot static to a tablet for backup indicated airspeed etc. 

Pretty neat. (More that your project but a lot easier)

Attaches to inspection port under wing. 

http://nebula.wsimg.com/1ef3835a2c77b6b596f7809af439f75f?AccessKeyId=25B2510C35AB96A7E02E&disposition=0&alloworigin=1

 

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Rich, I don't want to spend a large amount of money on an AoA solution.  I'm just looking to activate the existing AoA function of my Dynon, if it's not terribly difficult to do.  If it's very hard, I'll just skip it; my airplane has not fallen out of the sky yet.   :)

 

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I'm curious why AOA isn't used more for approaches and landing. Coming from a military background, using AOA for approach and landing speeds was very useful. No final approach speeds to compute, as AOA is independent of weight, bank angle or CG.

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I think the way we fly LSA planes , your basic airspeed ( and the associated sound/feel) of the plane is a very good proxy for the AOA value.

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I understand that but within the performance envelope typical sport ( or private pilots for that matter ) fly , slow flight or departure type stall, is pretty much the only time they will approach really high AOA setups ... is it not ? 

 

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The CTSW pitot tube runs thru a plastic tube and stiff shielded wire can be run thru it ( I have done it ), however there is a grommet at the wing root so you have to pull the wing out a little. I don't see a need for an AOA on this aircraft as it has the best stall characteristics of any plane I have ever flown and you have to be very inattentive to stall this plane. I suppose if you do, it will just kill you slower than other planes.

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I don't see a need for an AoA either.

I have looked into installing a different pitot tube for the AoA and it was not going to work out because of the structure and metal tubing inside the existing pitot tube area. You may open a can of worms you can't put back in the can.

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The AOA for the RV-12 looks like a static port and is placed on the underside of the wing a few inches aft of the leading edge. Completely separate from the pitot. Maybe it could be done on the CT?

Why separate from the pitot you may ask? Because the -12 has the pitot in the prop hub.

Why in the prop hub? Because Van's designed it so the wings would be easily removable for trailering and garage storage.

I bet if you polled all the owners you would find 99% of them only take the wings off because it is required at annual.

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