Martin P6M-2 SeaMaster

David F. Plummer · Mar 13, 2003, 01:09 AM

Hello Jet Jockies!

I'm building a 1/16th-scale, EDF-powered model of the Martin P6M-2 SeaMaster flying boat; a photo of the model in it's current state is attached. If anyone has built a model of this aircraft and has some suggestions on how to actuate the hydro flaps (used to help steer the aircraft when on the water), I'd appreciate some suggestions. Clearly, they need to operate in conjunction with the rudder, but some suggestions for the mechanical acutation technique would be appreciated.

Dave P.

GregG · Mar 13, 2003, 01:58 AM

OMG!!!

She is looking oh so fine Dave! I've been wondering when you were going to give us an update. What does she weigh right now?

Larry Dudeck · Mar 13, 2003, 12:42 PM

I hope that is a standard size car table.

Sweet looking.

Howzabout some detail..

FOShowNoClass · Mar 13, 2003, 01:04 PM

Dave,

I built a model from RCM several years ago called the Raven...I think. It was a bird-like model that used drag flaps to turn it. It made very flat turns like a real bird does. The linkage used, if I remember correctly, had bellcranks and springs in it. The drag flaps came out of the bottom of the wing. The spring was used to used to keep the other flap from coming up when the other flap was down. I don't know if this is what you are looking for. You could make a control horn for the servo the would allow you to use the drag flaps and rudder from the same servo. How you would keep it from deploying in flight...well, haven't thought of that yet. You could always have seperate servos and mix it in through the transmitter. Hope this helps in some way. Absolutely gorgeous model!

Will

Ductedfann · Mar 13, 2003, 01:18 PM

WOW!!! Would you make me one?:
No really. Pay you in gold.p

scruz · Mar 13, 2003, 01:38 PM

gold what?

uncljoe · Mar 13, 2003, 02:31 PM

David
Ray Cannon (see ELI aug 2001) XP6M which used Hydro flaps See pix page 24 also a dolly for rog operations
Semper Fi
Joe

LotusTRBO · Mar 14, 2003, 10:11 AM

Very impressive ... we have come such a long with with edf's. I believe that you could use mixing as I have done with my B-2 for the drag rudders ... mix them in with the rudder ... you would only really use that on the ground (unless you fly with rudder which most don't unless the are flying patterns). You can adjust the servos (if you have a computer radio) to have a null up swing so they would either be down or nutral. I hope this makes sense and was of some help.

Lonnie

AKA

LotusTrbo

Ductedfann · Mar 14, 2003, 10:53 AM

scruz, Are you representing Mr. D.F. Plummer, or do you have one for sale?

JasonJ · Mar 14, 2003, 11:40 AM

Awesome project! I was watching discovery wings and saw the big Russian jet powered flying boat that had its engins mounted kind of A-10 style, yours look like a better idea. You should get some extra lift from those EDFs pulling air over the wings too!
Yeah, I think I would mix the setup like flaps, have use a switch channel to put them down and then mix the with the rudder channel only when the flap switch is down.

Ken Lapointe · Mar 14, 2003, 11:47 AM

Very nice, looking forward to more pics as you progress

Ken

David F. Plummer · Mar 15, 2003, 01:01 AM

Hello Fellow Jet Builders/Fliers!

I'm a little slow responding to the questions due to a recent/ongoing conversion to a new computer/operating system/internet provider. I'll try to give some details on the model, and will provide a bit more at a later date when I'm further along in the conversion process:

I'm building the model scratch, based primarily on Stan Piet and Al Raithel's excellant book, "Martin P6M SeaMaster." I also obtained some sparse information from some other sources; fortunately, the Piet/Raithel book had fuselage cross-sections. The major model stats are:
W/S = 77.2"; Fuse. length = 90.2"; wing airfoil = NACA 63A210, 12%, plotted with MacFoil; wing area is 7.42 ft sq; target weight is (gulp!) about 13.4-14.5 lbs.;motors are TBD; fans are 4 x HW609; batteries are TBD.

I've succeeded in getting the spoilers to work satisfactorily (there are no ailerons). The cockpit is fairly well detailed. The empenage was a major problem to construct and get satisfactory actuation/throws on the elevators; fortunately, the aircraft had the rather large, bullet-shaped fairing where the horiz. and vertical stab joined, so I was able to get the elevator servo installed in the model's fairing.

At present, the model weighs a bit over 9 lbs, which includes all the radio gear, battery, and servo, except for the hydro flap servo. I just recently (after a long wait) received a couple of motor/fan adapters, so can now (belatedly) do some test/evaluation of the power element.

I hope this is enough to give you a brief idea of my progress so far. I will try to include some additional photos, but have included one of my mock-up to figure out the hydro-flap actuation scheme. Now I only have to figure out how to keep the water out ...

More later,

Dave P.

Bruce DeVisser · Mar 15, 2003, 03:56 AM

Dave,

Very nice (and ambitious) scale effort! I suggest you use a small metal-geared servo for each hydro door. You can use a WTOB (water-tight output bushing) for the control rod; boat guys use them, and I think Dubro makes them.

Mix rudder to both of them, but only in one direction each; this will also maximize your servo throw. Use a switch to activate the mixer when you are on the water. You need to use a strong enough servo to hold position against the water pressure for reliable steering at all speeds.

You can seal the compartment under the door and make the door from carbon fiber for stiffness and strength.

Please keep us informed of your progress.

Bruce

David F. Plummer · Mar 15, 2003, 11:55 AM

Hi Bruce!

Many thanks for the suggestion on the hydro flaps; I'll certainly consider it. I'll try to find the DuBro 'gasket', as the water penetration in the aft end of the hull could prove to be a major problem. I'll consider also the carbon-fiber doors, as I have some sheet material on hand. I'll add some photos, etc., as I progress.

Dave P.

David F. Plummer · Mar 22, 2003, 10:35 PM

Hi Interested Martin Fans!

I'm still plinking away on the P6M-2 model, but some very helpful advice from Ray Cannon provided me with the 'final solution' to the hydro-flap actuation problem. Ray has previously built a model of this aircraft, and his help was just what I needed. Attached (I hope) are some additional photos of some parts of the model, and of the hydro-flap actuation scheme.

Regards,

Dave P.

Mar 13, 2003, 01:09 AM	#1
David F. Plummer Registered User Join Date: Oct 2000 Location: Bellevue, WA USA Posts: 164	Martin P6M-2 SeaMaster Hello Jet Jockies! I'm building a 1/16th-scale, EDF-powered model of the Martin P6M-2 SeaMaster flying boat; a photo of the model in it's current state is attached. If anyone has built a model of this aircraft and has some suggestions on how to actuate the hydro flaps (used to help steer the aircraft when on the water), I'd appreciate some suggestions. Clearly, they need to operate in conjunction with the rudder, but some suggestions for the mechanical acutation technique would be appreciated. Dave P. Attached Thumbnails 75.7 KB · Views: 742

Mar 13, 2003, 01:38 PM	#6
scruz Registered User Join Date: Jun 2002 Location: Allbrightsville, PA Posts: 29	gold what? Last edited by scruz; Mar 13, 2003 at 01:50 PM.

Mar 14, 2003, 10:53 AM	#9
Ductedfann Ductedfans.comJepeusa.com Join Date: Jan 2002 Location: mid west Posts: 627	scruz, Are you representing Mr. D.F. Plummer, or do you have one for sale? Attached Thumbnails 15.8 KB · Views: 380

Mar 15, 2003, 01:01 AM	#12
David F. Plummer Registered User Join Date: Oct 2000 Location: Bellevue, WA USA Posts: 164	Hello Fellow Jet Builders/Fliers! I'm a little slow responding to the questions due to a recent/ongoing conversion to a new computer/operating system/internet provider. I'll try to give some details on the model, and will provide a bit more at a later date when I'm further along in the conversion process: I'm building the model scratch, based primarily on Stan Piet and Al Raithel's excellant book, "Martin P6M SeaMaster." I also obtained some sparse information from some other sources; fortunately, the Piet/Raithel book had fuselage cross-sections. The major model stats are: W/S = 77.2"; Fuse. length = 90.2"; wing airfoil = NACA 63A210, 12%, plotted with MacFoil; wing area is 7.42 ft sq; target weight is (gulp!) about 13.4-14.5 lbs.;motors are TBD; fans are 4 x HW609; batteries are TBD. I've succeeded in getting the spoilers to work satisfactorily (there are no ailerons). The cockpit is fairly well detailed. The empenage was a major problem to construct and get satisfactory actuation/throws on the elevators; fortunately, the aircraft had the rather large, bullet-shaped fairing where the horiz. and vertical stab joined, so I was able to get the elevator servo installed in the model's fairing. At present, the model weighs a bit over 9 lbs, which includes all the radio gear, battery, and servo, except for the hydro flap servo. I just recently (after a long wait) received a couple of motor/fan adapters, so can now (belatedly) do some test/evaluation of the power element. I hope this is enough to give you a brief idea of my progress so far. I will try to include some additional photos, but have included one of my mock-up to figure out the hydro-flap actuation scheme. Now I only have to figure out how to keep the water out ... More later, Dave P. Attached Thumbnails 80.7 KB · Views: 336

Mar 22, 2003, 10:35 PM	#15
David F. Plummer Registered User Join Date: Oct 2000 Location: Bellevue, WA USA Posts: 164	Hi Interested Martin Fans! I'm still plinking away on the P6M-2 model, but some very helpful advice from Ray Cannon provided me with the 'final solution' to the hydro-flap actuation problem. Ray has previously built a model of this aircraft, and his help was just what I needed. Attached (I hope) are some additional photos of some parts of the model, and of the hydro-flap actuation scheme. Regards, Dave P. Attached Thumbnails 49.1 KB · Views: 226

Mar 13, 2003, 01:58 AM	#2
GregG Speed Demon Join Date: Dec 1999 Location: Antioch,CA,USA Posts: 11,390	OMG!!! She is looking oh so fine Dave! I've been wondering when you were going to give us an update. What does she weigh right now?

Mar 13, 2003, 12:42 PM	#3
Larry Dudeck Registered User Join Date: Sep 2000 Location: Williamsville, NY, USA Posts: 3,847	I hope that is a standard size car table. Sweet looking. Howzabout some detail..

Mar 13, 2003, 01:04 PM	#4
FOShowNoClass Registered User Join Date: Sep 2002 Location: SDF Posts: 117	Dave, I built a model from RCM several years ago called the Raven...I think. It was a bird-like model that used drag flaps to turn it. It made very flat turns like a real bird does. The linkage used, if I remember correctly, had bellcranks and springs in it. The drag flaps came out of the bottom of the wing. The spring was used to used to keep the other flap from coming up when the other flap was down. I don't know if this is what you are looking for. You could make a control horn for the servo the would allow you to use the drag flaps and rudder from the same servo. How you would keep it from deploying in flight...well, haven't thought of that yet. You could always have seperate servos and mix it in through the transmitter. Hope this helps in some way. Absolutely gorgeous model! Will

Mar 13, 2003, 01:18 PM	#5
Ductedfann Ductedfans.comJepeusa.com Join Date: Jan 2002 Location: mid west Posts: 627	WOW!!! Would you make me one?: No really. Pay you in gold.p

Mar 13, 2003, 02:31 PM	#7
uncljoe Col.Hooligan Air Force Join Date: Jul 2001 Location: mays landing nj Posts: 1,138	David Ray Cannon (see ELI aug 2001) XP6M which used Hydro flaps See pix page 24 also a dolly for rog operations Semper Fi Joe

Mar 14, 2003, 10:11 AM	#8
LotusTRBO LotusTRBO Join Date: Feb 2000 Location: West Hollywood California Posts: 336	Very impressive ... we have come such a long with with edf's. I believe that you could use mixing as I have done with my B-2 for the drag rudders ... mix them in with the rudder ... you would only really use that on the ground (unless you fly with rudder which most don't unless the are flying patterns). You can adjust the servos (if you have a computer radio) to have a null up swing so they would either be down or nutral. I hope this makes sense and was of some help. Lonnie AKA LotusTrbo

Mar 14, 2003, 11:40 AM	#10
JasonJ Dude, where's My Plane? Join Date: Mar 2001 Location: Green Lane PA USA Posts: 2,163	Awesome project! I was watching discovery wings and saw the big Russian jet powered flying boat that had its engins mounted kind of A-10 style, yours look like a better idea. You should get some extra lift from those EDFs pulling air over the wings too! Yeah, I think I would mix the setup like flaps, have use a switch channel to put them down and then mix the with the rudder channel only when the flap switch is down.

Mar 14, 2003, 11:47 AM	#11
Ken Lapointe Build'em and Crash'em Join Date: Oct 2000 Location: Narragansett, RI Posts: 1,946	Very nice, looking forward to more pics as you progress Ken

Mar 15, 2003, 03:56 AM	#13
Bruce DeVisser E-Scale & Sailplane Guy Join Date: Mar 2001 Location: San Jose, Ca USA Posts: 179	Dave, Very nice (and ambitious) scale effort! I suggest you use a small metal-geared servo for each hydro door. You can use a WTOB (water-tight output bushing) for the control rod; boat guys use them, and I think Dubro makes them. Mix rudder to both of them, but only in one direction each; this will also maximize your servo throw. Use a switch to activate the mixer when you are on the water. You need to use a strong enough servo to hold position against the water pressure for reliable steering at all speeds. You can seal the compartment under the door and make the door from carbon fiber for stiffness and strength. Please keep us informed of your progress. Bruce

Mar 15, 2003, 11:55 AM	#14
David F. Plummer Registered User Join Date: Oct 2000 Location: Bellevue, WA USA Posts: 164	Hi Bruce! Many thanks for the suggestion on the hydro flaps; I'll certainly consider it. I'll try to find the DuBro 'gasket', as the water penetration in the aft end of the hull could prove to be a major problem. I'll consider also the carbon-fiber doors, as I have some sheet material on hand. I'll add some photos, etc., as I progress. Dave P.

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