 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
longg(at)pjm.com
Guest
|
 Posted: Thu Jul 15, 2010 7:15 am Post subject: Panel Accessible breaker for Mission Critical Item |
 |
|
Goal: to determine if there is added value in being able to reset a
breaker for a mission critical item.
Assumptions: I have plenty of fuse busses in my airplane (don't sell me
on the fuse vs. breaker crap) and only a couple of breakers. I'm not
worried about one more $20 breaker.
Problem: My aircraft, Lancair Legacy is not designed to land without
flaps; not even just for fun. If you do you put yourself in a situation
of a high speed landing with no visibility over the nose. Flaps fix that
problem in that they provide the option of being able to modify the wing
cord such that you can see a bit of the runway during landing. So, all
is well when the flap motor has electrons.
No, there is no Piper J bar on a Legacy. Electric only and no emergency
dump option. The only option is to find a long runway and fly it in.
My question: Am I at negative odds using a fuse which I might have to
fish for if my flaps go out during flight or do I replace that option
with a breaker on the panel?
Thanks,
Glenn
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
| Back to top |
|
 |
Dennis Johnson
Joined: 10 Jan 2006
Posts: 89
Location: N. Calif.
|
| Posted: Fri Jul 16, 2010 8:54 am Post subject: Panel Accessible breaker for Mission Critical Item |
|
|
I've been flying my Lancair Legacy for over three years and 350 hours. I do not agree with your characterization of a no flap landing in a Legacy. I wouldn't fly it if I thought it was unsafe to land without flaps. You're right that you need a higher landing speed and a longer runway, but at least where I fly, there are a dozen suitable runways within my normal fuel reserve. The last time I did a no flap landing, for practice, was on a 6,000' runway at sea level and I don't think I used more than half the runway. But it is something that needs to be practiced because you're right that it's much easier with flaps than without.
There are plenty of single points of failure in the flap system and the fuse or circuit breaker is only one of them. I'd recommend a comfortable Plan B if any of them caused a flap system failure.
By the way, I have a 7 amp ATO/ATC fuse protecting my wing flap circuit. During construction, I installed a 5 amp fuse based on measurements of the flap motor's current draw. However, once I started flying, I found that I could sometimes blow the fuse if I instantly reversed the flap direction. For example, let's say I'm on the ground running the before takeoff checklist and lowering the flaps to 10 degrees. I overshoot a little and immediately move the flap lever to the up position to get back to 10 degrees. That immediate reversal of flap movement sometimes blew the 5 amp fuse. I replaced it with a 7 amp fuse and have not had a problem since; about three years and over 300 hours.
Another poster expressed concern about circuit protection for the landing gear. That's near the bottom of my worries, because the backup gear extension system relies on gravity and proper installation and lubrication of the landing gear system. I practice the alternate landing gear extension from time to time and perhaps that's why I'm so comfortable with it. My hydraulic pump is protected by a 40 amp ANL current limiter, which I don't believe the pump could possibly blow, absent some failure that would disable the system anyway.
Dennis
[quote][b]
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
