RFguy
-
Posts
3,528 -
Joined
-
Last visited
-
Days Won
49
Content Type
Profiles
Forums
Gallery
Downloads
Blogs
Events
Store
Aircraft
Resources
Tutorials
Articles
Classifieds
Movies
Books
Community Map
Quizzes
Videos Directory
Everything posted by RFguy
-
The FI rotax does not begin to charge the battery until 7 seconds or so over 2500 RPM. So after oil pressure is established, need to get RPM up to 2550 etc so the battery starts charging, this is obvious by looking at the ship battery voltage. Until that time, the ship battery is in discharge for internal ship loads (and not yet being charged by ALT-B) The ALT-A begins to run the ECU at about 1200-1300 RPM, approx. Very low RPM in flight (how ?) might cause some ECU confusion and require ECU to be powered by the ship battery if RPM too low to run the system from ALT-A/B Just discussing the rotax here because it's a good example of how it can be done. Putting aside miscellaneous annoyances and sensor issues of the FI rotax. -
take a good look at the fuel injection pump current requirements under various condix, they can pull a fair bit, and that you might have BOTH pumps on due to design (or error ?) Given that good quality, sealed non liquid electrolyte batteries generally do not have sudden failures, it's probably a good option as a power source. a strong schottky diode or MOSFET schottky implementation with some sort of current limit would be a simple and reliable option. A big schottky with say only 20V 30V reverse barrier will be pretty low voltage drop. maybe something like 12 or 14 gauge wire will serve as a current limit....maybe aim for wire resistance = diode drop under normal conditions, as a starting point. that will be fine as long as the charging system gets up to 14.4 , 14.6V region
-
Mike I gather the UL system has one alternator and one ship battery. usually the single alternator is doing double duty and I think that's a bad idea, since the engine systems are not isolated from the troubles and switches and breakers and ge-finger trouble of the user.... The only way to really get away from it is a 2nd power source., or perhaps an independent feed from the battery with its own isolation relay (or a 2nd battery only for the UL so that buys you an hour etc, and some switch that you can cut over the Ul to main ship battery- but then you have a single failure point in the cabin maybe.... so, some thought required to escape the single power feed issue. The UL systems having its own feed from the battery and own isolation switch etc is probably the simplist.
-
Mike On the UL electrical - I wonder how the dual ECU setup power is set up. Given the issue and what you;'ve told me, it might be worthwhile to consider modifications / additional systems. a recent story... I know a bit about the electricals of 915 rotax's these days. I had to find/fix a charging intermittant. The Rotax has two alternators - A and B (ALT A, ALT B) A is rated about 15A, B at 30A. "A" normally runs the ECUs (all rotax electrical) (thru their 'fusebox/switchbox"), B is routed to the ship to run systems and charge the ship battery. . In case of a failure of ALT A, the the system commenderes the B ALT and the ship is cut loose to run on ship battery. At start because there is no A or B, ship power is routed to the ECU C input until A(or B) gets going) then once running the ship power source is removed. and I can confirm it all works well. Everything including the dual injection fuel pumps are powered from the rotax control box, nothing can stop the rotax once it's going.... (except individual ECUs can be disabled- LANE A, LANE B) . I've demonstrated removing the battery terminals while the prop was going AND disconnected the output of ALT-A and it fails over onto ALT-B immediately cutting the ship lose.
-
the way it is described in the part91 / FAR USA regs is suitable, I will look it out. It describes the result / protection required, but not how it is acheived, IE as long as the intention is achieved. good regulation
-
dunno if I would use an SSR in that service The SSR must be rated at the stall current, which is probably 2 x the battery CCA !
-
surely those rectangular square cornered windows are no good for high cycle count airframe pressurization cycles?
-
FWIW https://www.airservicesaustralia.com/aip/current/dap/BUNAD01-175_30NOV2023.pdf accident report at 1445 local
-
remarkable only for experienced on type, no doubt . There has to be more to this. No sane pilot goes off into full on type crosswinds with little time on type. ....
-
This is the sort of crash where you want the battery to have a isolator at the battery, like GA aircraft. Maybe even double pole. and have non cracking insulated covers on exposed terminals
-
no issue with the door open of a PA28 . might cost you a bit of drag , that's all. and a bit of noise. as for creating a problem near stall? no. Not compared to what those big wings are doing. Not sure where that wive's tail came from. (no offence to the wives, either)
-
pilot survived. 'trapped in the crash' lucky it didnt catch fire. https://www.abc.net.au/news/2024-03-01/plane-crash-bunbury-airport-authorities-responding/103536362
-
but you dont turn the ignition for the stall warning test, you turn on the MASTER switch, and also run the fuel pump to dump the gascolator
-
piper door is easy to reclose in flight (it also has the upper latch) AS LONG AS you do it as the POH tell you to. (open storm window, close vents) . that storm window is something special isnt it ? I thought it was for getting a bit of cool air and for your ground crew to pass you the loading manifest through the window, but no, its for looking where you are going when you cant see where you are going.
-
well with an old Cherokee, you wont have any problems with the door staying shut. 🙂 🙂(although I fixed mine)
-
Then, you can have the worst of both worlds and get a MID WING ! fly a Viking SF2A Cygnet. Markdun has one. I have flown one of these as co pilot. nice https://en.wikipedia.org/wiki/Viking_SF-2A_Cygnet
-
It is not true for all low wings that they are hard to get out of if flipped. It would be easy to get out of a flipped over PA28 cherokee etc if it flipped over. Has a bit tall fin, also. I have no idea how you might flip one over though. PA28 is a low wing but has a side door. (and a baggage side door you can get in and out) . also in a PA28 you have a roof over your head. no sunburn. I have seen a couple of low wing coanopies at oshkosh and they had pins around the canopy that unlocked the whole thing to come off into pieces... Brendan, its time you got a Cherokee.
-
yeah if you can do it yourself just arm yourself with lots of old blankets, foam pieces , straps etc so that nothing rubs on anything, even stuff with clearance like cables can get a vibration going and start rubbing etc, everything must be damped.
-
OK.... I can imagine they dont spin past incipent, so much drag. There is a common misconception that a kg off at 1m distance at the front is the same as 100g put 10m out the back... that's all...
-
Get a logistics company to do it This way it will be their boys and trucks all the way. You can get a door to door, but since they are the only carrier you can trust them using their hubs. I use PFM Logistics. I use them for moving things like high value robots, I got onto them from a mate that moves $100,000 photo printer plotters (well known company).
-
extralite said " their flight characteristics are improved by adding weight to the tail wheel." adding weight to the tail wheel ? are you insane ? You increase the moment of inertia doing that, adversely affecting spin recovery. It is NOT just a simple matter of weight off one end is OK at the other, moment of inertia is about distance squared !!! FFS. NFW I would get in a plane that someone did that. Anyone reading this I would strongly advise against it unless it has been re-flight tested by someone who knows what they are doing in all envelopes.
-
Parlous State of Spin Knowledge and Training
RFguy replied to djpacro's topic in Student Pilot & Further Learning
but i might have bent the airframe on the recovery... hard in the sim to grasp everything. -
Parlous State of Spin Knowledge and Training
RFguy replied to djpacro's topic in Student Pilot & Further Learning
Factory handling notes for the PA28 suggest not immediately jumping on the opposite rudder with a wing drop on a stall , just centralize the controls, power off if necessary......as unnecessary use of full rudder may invite an 'undesirable aircraft state' ... in the simulator , in a rather unhelpful pro-trouble aircraft configuration, I got a rollover and inverted half ?spin? to commence.... let go of everything, nose down dive and recovery. -
Master isolation relays should be required mandatory on all aircraft. But its not. although in VH world (non experimental) , for a certified aircraft you will not get cert if it doesnt have one because it will not be able to meet the criteria of being able to isolate the battery. I suspect many Jabiru fires are due to no battery isolator, and watch out for Sling also, no battery isolator in at least one aircraft I have seen. The other Jab fires are probably overflowing carbs. cheap https://www.aircraftspruce.com/catalog/elpages/masterrelay.php although that one is marginal on starter current if a 3300 jab, but OK for a 4 cyl rotax/jab otherwise : https://www.aircraftspruce.com/pages/el/relays/sts-12a24a.php
