My Flying Boat

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Othman

Well-Known Member
Joined
Aug 23, 2004
Messages
355
Location
Ottawa, ON, Canada
I recently started on design of the structure. The wing and tail surfaces will be made from metal for sure, and I've almost convinced myself to make the fuselage metal too (the only reason I would make it out of wood is for 1) construction techniques 2) i wanted to have ceader strip-like finish on the forward upper deck... might still have it with the metal structure as well).

I've since abandoned the idea of a single engine driving 2 remote props, and I'm leaning towards 2 smaller pylon mounted engines.

At the same time I am also working on a conventional plane, single-engine tractor configuration, that uses the basic fuselage and wing dimensions as the flying boat. It could aslo be mounted on floats to become a seaplane.

if you're interested in talking seaplane design, send me an e-mail at ashraf.othman@rogers.com

Regards
 

BD5builder

Well-Known Member
Joined
Jul 29, 2005
Messages
102
Location
Greenville, SC
Not sure if you've ever thought about possibly using 2 RC-airplane 2 stroke Gas engines, as there are some that are extremely reliable and put out a substantial amount of power.

Or possibly a Hirth 3203 with the fuel injection option. It gets rid of the notorious troubles 2 strokes give you with carburators..

Also, on the drive system, how about implementing the already tried and true BD-5 drive system? It already uses a set of belts along w/ a clutch on the drive end to get rid torsional vibrations caused by the power pulse's of the engine. there's a description and a sketch of the system on this website:

http://www.prime-mover.org/Engines/Torsional/contact1/contact1.html

and it can be purchased for about $1600 from a few places.
 

Othman

Well-Known Member
Joined
Aug 23, 2004
Messages
355
Location
Ottawa, ON, Canada
I will most definitely seek out 4-stroke engines over 2-strokes.

I did study the BD-5 drive system a while back. The use of the sprague clutch to eliminate "prop-driving-engine effects" is exactly what is needed; however, a straight installation into my application is not possible... I would still have to do some engineering to make it work.
 

orion

Well-Known Member
Joined
Mar 2, 2003
Messages
5,800
Location
Western Washington
I would strogly urge against the sprague clutch - although it does stay locked for a bit when you throttle back, it does eventually become disengaged, resulting in a freewheeling prop - sort of equivalent of throwing out a large chute. About a year ago there was a fatalitiy in a BD5 when the engine quit on downwind and the windmilling prop virtually stopped the airplane in the pattern, keeping it from reaching the runway, which resulted in a forced landing in an inhospitable area that killed the pilot.

Although I'm not sure how many, I have heard of several accidents of this particular nature with the BD5.

And no one I've been able to track down is able to tell me the reason for the sprague in the driveline. The HTD belt used acutally does have inherent damping chatracteristics so if the system is designed and installed correctly, there should be no need for the sprague since the belt itself is able to dampen out feedback impulses.
 
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Staggermania

Well-Known Member
HBA Supporter
Joined
Apr 11, 2014
Messages
347
Location
Dahlonega Georgia
Don't know if the OP is still around, but how about considering an IC to generator to twin electric motors? Betters efficiency than hydraulics. Simpler, I think, than belt drives.
 
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