Dieselfume
Well-Known Member
I've already posted this on rec.aviation.homebuilts and recieved many more replies than expected, but I'd like to hear what you guys (and gals) at HBA think.
I was wondering if anyone else was designing (or maybe even progressed
to building) a homebuilt aircraft based on the PBY Catalina? The
reason I ask is that I have been thinking of designing one for some
time. Now that I have 1 year to go before finishing my BS in ME, I
have decided to begin working on a conceptual design.
Hopefulley I'll get around to posting some of my newer PBY stuff on my
website before too long.
I'd like to see what you guys (and gals) think of my idea. Basically I
want an adventure/bush/recreational aircraft. There are a lot of
single engine amphibs out there around 100-200hp, so I'm not going to
design something that basically already exists. What I want these
aircraft wouldn't be able to do anyway. I am looking to build
something where there is nothing very similar to it. It would be
similar size to a Widgeon, but how many of those do you see around.
I'd like to see a C185 or Beaver owner consider buying one of these. I
also don't want to go through the nosebleed the seawind went through
(basically design/build it right the first time and no BS).
I won't be building everything exactly to scale, and it will be made
of mostly composite materials (glass, CF, some kevlar, foam/balsa,
epoxy). You could call it an evolution of a PBY-6A with the R-2600
conversion. I have narrowed down the size that I am going to build.
50% scale. This puts us at 52' WS and 4750 gross (revised, 4500 gross, 4750 is a bit ambition on 2x160hp), and a pair of
160-200 hp engines. My minimum goals (on 200 hp) are 2000 lbs useful
load, stall w/flaps 49 mph, 75% cruise 167 mph, takeoff from water in
under 900 feet, and have a 1500 statute mile range. I want this
aircraft to be affordable to build and operate (not RV-4 affordable,
but affordable for its size). So far my powerplant of choice is the
deltahawk diesel (although one could put whatever they wanted in for
an engine, many choices around 160-200 hp). A pair of 200hp diesels
would give this PBY the same fuel burn that a 300hp lycoming would
(about 14-16 gph). That's it in a nutshell. Whatchya think? Sound
cool?
one of my responses was:
(regarding original PBY never had flaps)
"Yes, the PBY never had flaps, but I'm going to put some 30% chord
fowler flaps over about 70% of the span. Should be pretty close to
STOL then with a good power to weight ratio.
(regarding needing toget a CAD platform)
I've got access to Catia V5, so I'm ok there. I have more experience
using ProE wildfire, but that's what I got.
(regarding LG weight)
The gear will weigh a lot, and I want to make sure it is up to rough
fields. I think it can be reasonable in weight if one puts enough time
into it.
(RE: safety)
I've been looking at safety issues right off the bat with this
concept. I've already went through NTSB stuff on the Catalina as well
as other types, like the seawind. So I've been documenting problems
such as the nose wheel doors on the catalina collapsing causing a
nose-over in the water. You mention loosing an engine might be a
problem with 2x200 hp. I had been looking at the power loading of
several twins and have noticed many with similar power loading. In
fact a 1997 PA-34 Seneca V has 2 engines rated 200 hp continuous (220
for TO) with a gross of 4750 lbs, but a stall speed of 70 mph. But you
do bring up a good point about SE performance, and that's one thing I
will keep an eye on.
Thanks for your comments! Keep em coming!"
Some comments I've already recieved were
-landing gear might be heavy
-4750 gross would be a dog with 2x160hp. I revised my idea to 4500 gross, and someone else pointed out with the flaps, large wing area, and room for large dia prop (high thrust at low speed) would compensate for the heavy power loading.
-some suggested some existing designs or similar aircraft under development such as:
CL-215
http://www.geversaircraft.com (very "out of the box", possibly unfeasable design)
http://www.centaurseaplane.com (kinda ugly to me, not a twin, under my useful load goal, but very interesting otherwise, particularly hull design)
http://www.beriev-usa.com (already flying, but slow, heavy, small useful load, using 2x210hp, hate to see it dig a wingtip on landing, seems too easy to do)
Some other mentioned thinking of basically the same idea, one even mentioned it to a Rutan test pilot to tell Burt to get working on the idea.
Another mentioned in the so. Pacific only auto gas and diesel would be found and if there was a runway, you'd get Jet-A, no 100LL.
Well, that's the idea with some comments about it already, I'd like to hear any comments and suggestions. Thanks!
Tom
I was wondering if anyone else was designing (or maybe even progressed
to building) a homebuilt aircraft based on the PBY Catalina? The
reason I ask is that I have been thinking of designing one for some
time. Now that I have 1 year to go before finishing my BS in ME, I
have decided to begin working on a conceptual design.
Hopefulley I'll get around to posting some of my newer PBY stuff on my
website before too long.
I'd like to see what you guys (and gals) think of my idea. Basically I
want an adventure/bush/recreational aircraft. There are a lot of
single engine amphibs out there around 100-200hp, so I'm not going to
design something that basically already exists. What I want these
aircraft wouldn't be able to do anyway. I am looking to build
something where there is nothing very similar to it. It would be
similar size to a Widgeon, but how many of those do you see around.
I'd like to see a C185 or Beaver owner consider buying one of these. I
also don't want to go through the nosebleed the seawind went through
(basically design/build it right the first time and no BS).
I won't be building everything exactly to scale, and it will be made
of mostly composite materials (glass, CF, some kevlar, foam/balsa,
epoxy). You could call it an evolution of a PBY-6A with the R-2600
conversion. I have narrowed down the size that I am going to build.
50% scale. This puts us at 52' WS and 4750 gross (revised, 4500 gross, 4750 is a bit ambition on 2x160hp), and a pair of
160-200 hp engines. My minimum goals (on 200 hp) are 2000 lbs useful
load, stall w/flaps 49 mph, 75% cruise 167 mph, takeoff from water in
under 900 feet, and have a 1500 statute mile range. I want this
aircraft to be affordable to build and operate (not RV-4 affordable,
but affordable for its size). So far my powerplant of choice is the
deltahawk diesel (although one could put whatever they wanted in for
an engine, many choices around 160-200 hp). A pair of 200hp diesels
would give this PBY the same fuel burn that a 300hp lycoming would
(about 14-16 gph). That's it in a nutshell. Whatchya think? Sound
cool?
one of my responses was:
(regarding original PBY never had flaps)
"Yes, the PBY never had flaps, but I'm going to put some 30% chord
fowler flaps over about 70% of the span. Should be pretty close to
STOL then with a good power to weight ratio.
(regarding needing toget a CAD platform)
I've got access to Catia V5, so I'm ok there. I have more experience
using ProE wildfire, but that's what I got.
(regarding LG weight)
The gear will weigh a lot, and I want to make sure it is up to rough
fields. I think it can be reasonable in weight if one puts enough time
into it.
(RE: safety)
I've been looking at safety issues right off the bat with this
concept. I've already went through NTSB stuff on the Catalina as well
as other types, like the seawind. So I've been documenting problems
such as the nose wheel doors on the catalina collapsing causing a
nose-over in the water. You mention loosing an engine might be a
problem with 2x200 hp. I had been looking at the power loading of
several twins and have noticed many with similar power loading. In
fact a 1997 PA-34 Seneca V has 2 engines rated 200 hp continuous (220
for TO) with a gross of 4750 lbs, but a stall speed of 70 mph. But you
do bring up a good point about SE performance, and that's one thing I
will keep an eye on.
Thanks for your comments! Keep em coming!"
Some comments I've already recieved were
-landing gear might be heavy
-4750 gross would be a dog with 2x160hp. I revised my idea to 4500 gross, and someone else pointed out with the flaps, large wing area, and room for large dia prop (high thrust at low speed) would compensate for the heavy power loading.
-some suggested some existing designs or similar aircraft under development such as:
CL-215
http://www.geversaircraft.com (very "out of the box", possibly unfeasable design)
http://www.centaurseaplane.com (kinda ugly to me, not a twin, under my useful load goal, but very interesting otherwise, particularly hull design)
http://www.beriev-usa.com (already flying, but slow, heavy, small useful load, using 2x210hp, hate to see it dig a wingtip on landing, seems too easy to do)
Some other mentioned thinking of basically the same idea, one even mentioned it to a Rutan test pilot to tell Burt to get working on the idea.
Another mentioned in the so. Pacific only auto gas and diesel would be found and if there was a runway, you'd get Jet-A, no 100LL.
Well, that's the idea with some comments about it already, I'd like to hear any comments and suggestions. Thanks!
Tom
