f14av8r
Well Known Member
There are a lot of discussions on the website relating to the Dynon AOA/Pitot probe. I decided to post my installation experience here, since I installed mine in a RV-4.
During my condition inspection last week, I installed a heated Dynon AOA / Pitot probe, replacing the standard Vans unit. I estimate I spent about 10 hours on the task spread across about five days as I accomplished the rest of the inspection. The hardest part of this project, on a completed airplane, is routing the additional air line for the AOA system and the wiring for the heated probe if you choose to add that capability. I explored a lot of options but, in the end, decided to bite the bullet and remove the left tank to allow access for routing the necessary lines between the tank and the spar. I was terrified of removing the tank but, while it requires some careful work, it is not overly complex. The best tip I got (from a post here) and employed, was to slip thin sheets of plastic (I used for sale signs from the aviation aisle at Home Depot) between the rivet rows on the top and bottom of the rear of the tank after removing the screws. The plastic serves to break the very effective dimple-to-dimple locking that is in place and will allow the tank to come free much more cleanly, and without scratching the underlying surface.
It's always painful disturbing a nice paint job for a project like this. I struggled mightily with the decision to pull the tank. Fortunately, none of the screws were painted over but I was still concerned about pulling up the paint around the heads. I used one of the screw head cutters from ACS to cut around every screw head before I removed them. That approach was hugely successful. My paint job survived the experience quite well. I highly recommend the screw cutter kit. I've used in on a lot of other frequent removal screws on my plane and the technique works well. Here's the ACS link - https://www.aircraftspruce.com/catalog/topages/screwpaintcutterkit.php?clickkey=36690
Routing the new lines was straightforward but not easy. Working in the enclosed wing and finished fuselage makes for some added difficulty but it's perfectly doable. I elected to mount the tube directly outboard of the aileron bell crank access panel. I didn't add any additional support structure and find the installed probe to be very secure.
I mounted the controller for the heated probe on the access panel - that almost seemed a little too obvious and I'm half expecting somebody to tell me why that was a bad idea! It was a very simple solution though and seems to work well. If you choose my approach for controller mounting, just make sure you leave enough of a service loop in the wiring to remove and hang the panel when you need to open it for access. I used the "approved" Vans technique of drilling a small hole in the rib lightning hole to zip tie the wire loop and keep it clear of the bell crank.
I used the Safe Air install kit and the Gretz Mast (both acquired from ACS). That added $200 to the cost of the project but sure made things easier. You could easily assemble the Safe Air parts from standard heavy truck air brake line hardware and lines but, for a little over a hundred dollars, it simply wouldn't be worth the trouble. I only used a small percentage of the provided connectors though so they could reduce the price and parts count if they eliminated the parts they include for splicing off a second set of instruments / ADHRS. The Gretz Mast is a slam-dunk in my mind. The hardware is first rate and the joggled lip worked perfectly on my spar.
Setting up and calibrating the probe was quite simple. Somehow, the Dynon system just knows that you have installed the probe and, once you run the airborne calibration routine and set the audio levels, it works wonderfully.
As a former Navy pilot, I appreciate, perhaps more than most, the added value of an AOA display. It provides an added measure of safety in the landing pattern and, I like it during aerobatics as an "eyes off" indicator of speed at the low speed extremes. I also like the Dynon implementation - no vanes, extra hardware, etc. Really just one extra air line an you're done. For me, it was well worth the money and the effort.
Randy
During my condition inspection last week, I installed a heated Dynon AOA / Pitot probe, replacing the standard Vans unit. I estimate I spent about 10 hours on the task spread across about five days as I accomplished the rest of the inspection. The hardest part of this project, on a completed airplane, is routing the additional air line for the AOA system and the wiring for the heated probe if you choose to add that capability. I explored a lot of options but, in the end, decided to bite the bullet and remove the left tank to allow access for routing the necessary lines between the tank and the spar. I was terrified of removing the tank but, while it requires some careful work, it is not overly complex. The best tip I got (from a post here) and employed, was to slip thin sheets of plastic (I used for sale signs from the aviation aisle at Home Depot) between the rivet rows on the top and bottom of the rear of the tank after removing the screws. The plastic serves to break the very effective dimple-to-dimple locking that is in place and will allow the tank to come free much more cleanly, and without scratching the underlying surface.
It's always painful disturbing a nice paint job for a project like this. I struggled mightily with the decision to pull the tank. Fortunately, none of the screws were painted over but I was still concerned about pulling up the paint around the heads. I used one of the screw head cutters from ACS to cut around every screw head before I removed them. That approach was hugely successful. My paint job survived the experience quite well. I highly recommend the screw cutter kit. I've used in on a lot of other frequent removal screws on my plane and the technique works well. Here's the ACS link - https://www.aircraftspruce.com/catalog/topages/screwpaintcutterkit.php?clickkey=36690
Routing the new lines was straightforward but not easy. Working in the enclosed wing and finished fuselage makes for some added difficulty but it's perfectly doable. I elected to mount the tube directly outboard of the aileron bell crank access panel. I didn't add any additional support structure and find the installed probe to be very secure.
I mounted the controller for the heated probe on the access panel - that almost seemed a little too obvious and I'm half expecting somebody to tell me why that was a bad idea! It was a very simple solution though and seems to work well. If you choose my approach for controller mounting, just make sure you leave enough of a service loop in the wiring to remove and hang the panel when you need to open it for access. I used the "approved" Vans technique of drilling a small hole in the rib lightning hole to zip tie the wire loop and keep it clear of the bell crank.
I used the Safe Air install kit and the Gretz Mast (both acquired from ACS). That added $200 to the cost of the project but sure made things easier. You could easily assemble the Safe Air parts from standard heavy truck air brake line hardware and lines but, for a little over a hundred dollars, it simply wouldn't be worth the trouble. I only used a small percentage of the provided connectors though so they could reduce the price and parts count if they eliminated the parts they include for splicing off a second set of instruments / ADHRS. The Gretz Mast is a slam-dunk in my mind. The hardware is first rate and the joggled lip worked perfectly on my spar.
Setting up and calibrating the probe was quite simple. Somehow, the Dynon system just knows that you have installed the probe and, once you run the airborne calibration routine and set the audio levels, it works wonderfully.
As a former Navy pilot, I appreciate, perhaps more than most, the added value of an AOA display. It provides an added measure of safety in the landing pattern and, I like it during aerobatics as an "eyes off" indicator of speed at the low speed extremes. I also like the Dynon implementation - no vanes, extra hardware, etc. Really just one extra air line an you're done. For me, it was well worth the money and the effort.
Randy
