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View Full Version : Video: Kyosho Pby Catalina and The Donald5 E-Conversions...Fly!


wdahlstrom
08-14-2007, 12:46 PM
We finally got these planes in the air!

The Donald5 is a great first seaplane. It MUST be upgraded to a big brushless motor like a Mega. The key is getting off the water fast and the water tends to be sticky.
Esprit Model sell it:
http://www.espritmodel.com/index.asp?PageAction=VIEWPROD&ProdID=2184

and its sistership the Donald Pro (with ailerons)

We also got our Kyosho Pby Catalina twin up after much nursing and tinkering. Twins are fun but two of everything including gremlins.
Axi 2814/12
APC 9x6 props
Jeti77 Opto Plus ESC's (two)
we originally planned a 3s 8400 mAh setup comprised of two TP 3s 4200 mAh lipo packs in parallel. But we needed to reduce weight so we went with just on pack for a 3s 4200 mAh setup. One battery fed both ESC's with a custom Y connector (two Male Deans Ultra's leading to a single Female Deans Ultra then to the pack). This way the ESC's both feed from the same gas tank reducing the chance that one ESC "sees" a different pack than the other ESC and shuts off. Our experience with twin engine planes flying on one motor is generally not successful. A 5 minute flight took 2400 mAh out of the pack for a post flight voltage of 11.5 volts and a lukewarm pack.
Preflight includes lots of duct tape to seal up the hull of both planes. Taxiing is a wet experience and water in the hull is a fast way to add weight and kill takeoff speed.
Rx's tend to suffer when wet so we bag them in plastic. ESC's need to cool and they are more robust in a damp environment. The motors don't seem to mind the generous dousing's the get on takeoff (and crashes). They start right up again. On one hard landing the Donald came in hard and steep and was fully submerged momentarily like a foraging pelican! She popped right up, restarted without assistance, taxiied and took off shedding a trail of water but otherwise OK. the Donald is built tough and our numerous rough landings have been easy to repair.
Video:
The Donald5
http://media.putfile.com/The-Donald-RC-electric-seaplane
Kyosho Pby Catalina
http://media.putfile.com/Kyosho-Pby-Catalina-seaplane-RC-Electric

too bad the Kyosho is no longer available. Its BIG wingspan makes for a really impressive plane! Like most twins the key dimension is the max. prop clearance allowed between the motors and the fuselage. Our 9x6 props have about 1/8th inch clearance. Not much but enough. I don't think 3 bladed props would add anymore power and they would certainly drain the single 4200mAh pack that much faster.

dotyj
08-14-2007, 04:04 PM
Those are great. The Kyosho looks like a bit of a handful while taking off.

capngrog
09-09-2007, 10:25 PM
Great videos!
I have the Great Planes PBY, but have only flown it a couple of times. I also have the Kyosho PBY, but haven't put that one together yet. Being a newbie float plane pilot, I studied your Kyosho PBY takeoff sequence with care. I noticed that you kept what appeared to be full "up" elevator on it, even after it rose up "on the step" and was planing on top of the water. I looked closely and re-ran the sequence several times and it appeared to me that once up "on the step" and planing, the "rooster tail" was being generated by the very aft end of the fuselage as it was forced down into the water (by the full up elevator ?). It looks like when you finally did rise off the water, you immediately experienced a tip-stall and the airplane was very squirrelly until you got some airspeed up ... nice save by the way. Anyway, in my limited experience with my PBY and surfing the float/water airplane forums, it seems that the recommended takeoff technique is: full up elevator until up "on the step" and planing, then release most of the up elevator, letting the airplane gain airspeed and pretty much flying itself off of the water. Any thoughts on that? Have you made any more flights using different takeoff techniques? I'd appreciate your opinion, since it's clear to me that you have way more experience at this than I have.

Thanks for posting your video even though it showed a difficult takeoff. I get the feeling that a lot of folks only post video of the "picture perfect" flights, and the learning value of those is somewhat limited.
Regards, Grog

wdahlstrom
09-10-2007, 02:12 AM
We modified the water rudder by making it bigger. I think this created water drag. It was this drag that kept us on the step until we applied up elevator, stalled slightly and then recovered. The video is of my son flying the maiden. A few minutes later I took the controls and found my self in the same takeoff and stall situation, I did not recover and the plane stalled and crashed. It was slightly damaged. Lesson, keep the water rudder small. We'll cut it down from the 2 inch long 1/2 inch wide rudder to a 3/4 inch long version. Our setup is plenty powerful but the plane has to rise off the water not get jerked off by way of the elevator. I promise you it was not going off the step without adding a jerk of up elevator and that is tricky.

Bill G
09-26-2007, 03:25 AM
We modified the water rudder by making it bigger. I think this created water drag. It was this drag that kept us on the step until we applied up elevator, stalled slightly and then recovered.
And a perfect recovery at that. I fly hand launched EDF, and am aware of how absolutely those "crawling takeoff" saves must be.