Stock Sonex Drum Brake Fade

[Rynoth]

Had my first experience today (my 7th flight) of brake fade with the stock Sonex Drum brakes. This is more of an informational post than anything else since I couldn't find any other discussion on the topic.

Normal, possibly a bit fast on the landing, then applied maximum braking after touchdown. The brakes faded by around 15ish knots to the point that I couldn't stop the plane to make a taxiway and rolled another 100 feet or so without any real braking effectiveness. I'm not discouraged by this but found it an important point to be known about the stock drum brakes. If I apply them right after touchdown there's a good chance they will be ineffective to actually bring my plane to a full stop until I let them cool off for 30 seconds or so or it rolls to a stop.

I did test the brakes a minute later during taxi-in and they operated normally so I don't believe it was a cable control issue.

[peter anson]

Yes, the brakes are rubbish, but I normally fly from a fairly short airfield, runways are 2300 ft sealed and 1970 ft grass, and I have never needed more than about 2/3 of the runway. If you have the standard unsealed wheel bearings, make sure that no grease has leaked onto the drums.

Peter

[lgsievila]

Instead of putting up with the fade and waiting for the brakes to start the annoying squeaking that will happen, switch to hydraulic brakes soon and avoid the hassle. There may come a time when you really need effective braking like a runway incursion or some animal in front of you, etc. I installed Tracy O'Brien brakes and really like them. Don't have any experience with Sonex hydraulic brakes but I am sure they work fine too.

[Rynoth]

I did notice during my hard braking that the tail was trying to come up despite holding aft elevator, so the grab of the brakes wasn't an issue before the fade happened. They grab enough for max braking effectiveness, but only for a few seconds.

[Rynoth]

Video of my landing with the brake fade:

https://youtu.be/0GDk5Jx5tMg

[tonyr]

Dont hold the brakes on continuously.. pulse them.. they wont fade from overheating.

[Rynoth]

Dont hold the brakes on continuously.. pulse them.. they wont fade from overheating.

I've never fully understood this reasoning... if trying to stop over x distance from y speed to zero speed, and traction not being an issue (dry runway), how is pulsing the brakes any different than simply applying lighter brake pressure in terms of heat transfer to the brakes?