Great point Larry. Braking effectiveness deteriorates as the linings heat up as well. Riding the brakes over long distances can have the same effect as heavy braking.
After heavy braking the brake mechanism temperatures continue to rise for a period of time after the braking event as the heat is transferred from the linings to the rest of the brake and wheel assembly. This can lead to a delayed failure of the type you’ve described. I’ll leave the math to someone else but there is a maximum temperature to avoid damage to the components and period of time to delay between events that will allow the brake and wheel assembly to cool sufficiently to avoid failure. Repeated heavy braking events will increase this time significantly. It will seem like overkill but if conducting this type of testing/practice it would be good to know your brake temps after each run to stay below the max temps. A buddy with a now-ubiquitous IR thermometer could quickly check both brakes after each run. Ideally this type of activity can be done on a surface of significant length to avoid heavy use of the brakes. On the other hand, people have done this successfully so there is probably empirical data on how fast, how many runs, braking technique etc that they could share. Every airplane will be a little different but the info would provide a starting point. Cheers, Rick Rick Junkin Integrity demands Courage Sent from my iPhone > On Apr 18, 2021, at 10:38, Flesner <fles...@frontier.com> wrote: > > > With more and more KR builders going with tri-gear and steering with brakes > and the discussion of extended taxi test , it seems appropriate to remind > builders of taxi test and brake failure. I've read of at least one incident > where extended taxi test got the brakes hot enough to soften the non-metal > lines and fail with brake pressure. The flammable fluid ignited and the > airplane was consumed in the fire. There is an old adage that says "if it > happened once it can happen again". One more item to keep in mind when you > start testing your KR. Is your fluid flammable? Test without wheel pants to > help cool the brakes? Don't make repeated runs that require heavy braking to > stop? Use your best judgement. > > Larry Flesner > > ________________________________ > -Please see LIST RULES and KRnet info at http://www.krnet.org/info.html > -Change list delivery options at > https://list.krnet.org/list/krnet.list.krnet.org/ Affinity List Info Board > -Search recent KRnet Archives at > https://list.krnet.org/empathy/list/krnet.list.krnet.org/ > -Search John Boyea's decades of archive at > https://www.mail-archive.com/krnet@list.krnet.org/ ________________________________ -Please see LIST RULES and KRnet info at http://www.krnet.org/info.html -Change list delivery options at https://list.krnet.org/list/krnet.list.krnet.org/ Affinity List Info Board -Search recent KRnet Archives at https://list.krnet.org/empathy/list/krnet.list.krnet.org/ -Search John Boyea's decades of archive at https://www.mail-archive.com/krnet@list.krnet.org/
