cpt nj

You'll still have the weight issue with pneumatics because the accuators would have to be close to the tips of the wing for maxium torque ,I personally think his design is ingenious. Exellent work ! NJ

troydragons

i dont think itll be much more weight than what bowmasters is and hes ben flying his im guising for a while. the only thing im adding is another hatch a gear moter and 4 mini switches with some wire . i will be changeing my desighn a bit by adding a sheet of thin ply along top of wing for strength.

troydragons

As you can see in pic.2 i have some concerns abought no wood for strengthin this area.Does any body have any opinuns on it? As you can also see i also use some scrap wood i have from yard sticks.There of course will be2 heavy fiberglass sheets all around wing. Inpic. 3 you can see where all wood pieces are located.A thin piece of ply runs from 7th crossmember to wing tip on the top of wing.In pic.4 you can see some of the basswood sheets acsess hatches ,there willbe 5 on underside of wingto acsess drive moter ,electronics ,servos and drive screw and push rod to float.In pic. 5 you can see the drive screw for the floats. As you can see in pic. 8 float pushrod is not attached yet needs poly piece.Ive decided to put the screw drive in my wing for the floats , i still need the moter andthe polyurathane piece for the screw that ataches to the pushrod that pushes the crossmembers so that the floats go up and down.In pic.9,10,this is the switching mech. for lights sw. sw.is a three way sw. off-on-on guitar sw.found on e-bay works great.The pic. shows the sw. in off position next is nav. lights then nav. and constint lights .Lights runoff the resciver batt.This sw. setup goes in the center section of wing between engines with fuel tanks and engines and battery pack for screw drive moters.I think ill use one of the 12 v 10 cell batt. 2000 mah.electrifly for some longer life,for thedrive moters 7.2 v 9-1 geardrive.

glasairdriver

I plan to build the PBY this winter. I have been studying the plans and have a questiion. It looks like the 1/4 inch fuselage box is sheeted with 1/16 balsa at each former. It is shown as a line on each side of the former within the center box area. I don't see any label or notes explaining this. What have you all done?

troydragons

i started on the wings first, i haventfinishedthem yet . just did a cursary viewing of the other plans so . I cant wait to get to main fusalage though . speaking of which anyone install landing gear for the pby need some advice and pics. if posable.i am almost paid off on them with jet retracts , cant wait to see them .

FHD

Howdy
Im fixing,repairing a PBY with a 84" wing span.
Its powered by 2-OS LA 40,s.
It must have been a kit from some one,foam wings and a fibre glass fuse.
I have no plans etc.
Would some one please let me know where the CG should be.
Thanks.
Take care
Frank in Winnipeg

Thomas B

My Feedback: (4)

It is highly like that that 84" glass and foam PBY is the old G&P Sales kit. I actually flew one in the early 1990s.
I would go conservative on the CG and set it to about 22-24% of the center section wing cord. It will be a little bit nose heavy, but safe. You can ease the CG back a little after you get some stick time on it.

http://www.rcairplane.net/index1.html

The web site for G&P models is still up, but I am pretty sure he is out of busniess.

FHD

Howdy
Thank you very much for this info.
Its what i was looking for.
Thanks again,very much apprecicated.
take care
Frank

glasairdriver

I have just started my PBY build. The first thing was to mock-up the main landing gear retract unit so I could get exact installation dimensions. The attached video link shows the Century Jets retract unit in operation. The still photo shows the Robart wheels and brakes.

http://www.youtube.com/watch?v=FHCUAq_KBYE

glasairdriver

The Robart wheel and brake photo didn't make it. Let's try this again.

Mustang Fever

My Feedback: (2)

glasairdriver:

That is some pretty hardware. Could you answer a few questions on this project, as there is not a lot of info on this bird?

What is the wing area, and what does Fred say about ready to fly weight?

What engines does Fred recommend, and what are you going to use?

I would love to do a PBY, but found out the hard way that small ones are really difficult. There's just no room in that skinny hull until one gets up to monster scale.

MaxAdventure

My Feedback: (7)

Do you have the part numbers on the Robart wheel/brake? TIA

glasairdriver

The wing area of this model is 9.72 sq ft. Fred says the weight with the retracts will be in the 25 pound area. That gives a wing loading of 2.57 lb/ft2. My Extra 300 has a 9.06 sq ft wing and a loading of 2.14 lb/ft2. So the PBY will have a heavier wing loading than the Extra but the Extra is a pretty light, 3D capable airplane. For first flight, I would be careful not to overload the wing in a turn which could produce a tip stall and unwanted roll.

The PBY was originally designed for a pair of .60 cu in 2 cycle engines. I will be using a pair of Saito .82 cu in 4 stroke engines. I will use the Master Airscrew 12 X 8 or 12 X 6 three blade props.

The Robart wheels are p/n 13845A8B and the brakes are p/n 140.

http://www.robart.com/products/4-12-...el-brake-ready
http://www.robart.com/products/disc-...luminum-wheels

Mustang Fever

My Feedback: (2)

Thanks, guy.

That wing loading (41.12 oz per square foot) is right in line with a lot of big, scale birds. My TF B-25 is just shy of 40 oz/sq ft, and it is a real sweetheart.

Observing my bomber in flight, I've become convinced that bigger models stall at a much higher angle of attack than smaller ones, so things don't happen quite so quickly and it's not so easy to get into trouble.

glasairdriver

I have been working on a waterproof box to contain the nose gear retract unit. That wasn't too bad to figure out, but the next question was how to open and close the gear doors. I have been using a graphics program (wish I had a mechanical design program) and have worked out the geometry to open and close the doors. The link is to a video of the operating door at a cross section at the aft end of the door. I think actuation will just be with a lever to the nose gear strut. That has not been worked out yet.

http://screencast.com/t/vxXOcsofuu

mrpby

Nice graphic on the nose door. You may find that the vertical clearance is critical. The full scale has an out and up sequence which solves that. Good luck. - Matt.

glasairdriver

I couldn't figure out how to do and out and up, so I went with a long arm. That makes the door move mostly out and not pivot as much as a short arm. I am only loosing about a quarter of an inch of ground clearance. That should be okay if I can keep it on the pavement.

glasairdriver

Some progress is being made.

glasairdriver

One of my big concerns with this build has been how to close and open the gear doors. You have previously seen the graphic of my design. Now it has been executed. I have done the starboard door so far and it works okay. It is held open with a spring and closed by the gear leg movement. When I get the port door installed, I hope the nose gear has enough power to close both doors because there will be a second spring for the port door. Anyway, we will see. If this doesn't work dependably, I may have to go with a servo arangement to opperate the doors.

Check out the video:
http://www.youtube.com/watch?v=7RILIKBYAw4

glasairdriver

Well, I am having great difficulty getting both gear doors to work. I am not sure it can be done with springs and levers. How have others done it? Separate servos or air cylinders on the doors? Even if I get the spring and lever system adjusted, I am afraid it will always be problematic. Any ideas?

teresos

You can easily follow my construction with my simple homemade magnetic sequencer which
I made for my CL 215.....

http://www.rcuniverse.com/forum/fb.asp?m=9570928

glasairdriver

Nice work. Thanks for the info.

glasairdriver

Well, I scrapped the use of levers and springs to close the gear doors and opted for cylinders and a sequencing valve. The installation is complete and now I can remove everything to paint the interior and continue the build. The landing gear installation was a huge concern for me but now it is done.

Watch the operation on YouTube
http://www.youtube.com/watch?v=q89fonqxpjM

troydragons

does anyone know where i can get some 9.1 planitary gear moters for my floats?banbots no longer sell them

glasairdriver

Check out Servo City
http://www.servocity.com/html/10-24v...tzone_gea.html