Consoldated PBY Catalina Q&A

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    AvatarMartin Klöpfer

    Hi Jan,
    looks good to me so far. 😉 Did you make a suction test?
    Yes, you’re right there could be some locks between F1 and F2. I’ll add some in the next version.

    AvatarJan Masek

    I did not, i will try it on completed fuselage on water. Aichi’s float were fine on 1.00 but there was some issue with floats anyway, never seen a scale start with that one … water airplane isn’t that easy after all.

    AvatarJan Masek

    Just for info, my plain fuse weight is 465g. I used 1.00 on all parts.
    Now, the cable tube is placeable from the top, if you forgot it as i did. I used also a pair of wires for leading all the fuse parts to correct position using rudder an elevator control holes

    AvatarJan Masek

    so takeoff weight with double 3542’s, double 2200 nanotech, double 30A and my settings is 2600g.
    it is a great build , i was today only on taxi tests, construction seems ok.

    – the spray rails are inadequate, please make them a little bigger and they are suposed to be in some angle to capture and deflect water.
    – water comes through the engines, through the tunnel to the front section
    – water sprays directly on ESCs, add there a deflector on top of the gondolas behind the motor mounts to hide the escs from direct water spray
    – if you add a little step just before the front of the canopy, it will efectively block the water from going under the hood
    – i am not exactly sure about the stabilizer mount, a little reinforcement should be present, as the rudder is mounted on top of it
    – please add a little box for the rx to be safe, if some water comes in …

    – using these fixers, you can get rid of the servo mount issue –

    and this is my beauty on water:)
    my build

    AvatarJan Masek

    I have to tell you, the flight experience is great, flyies extremely well.
    i did a few improvements – piece of sponge in the cable tunnels that blocks spray water, moved CG 10 mm further to tail, made improvised spray rails that goes further in the front and more angled. My first flight is here . On the landing I hit the float sooner so a little spin happened, but everything ok.
    To all you guys, dont forget to epoxy your ECS’s 😉 and add a little Nanotech electric or other oil on RX and servos


    I have printed, assembled and test-flown the Catalina.

    Good things: I printed it using the G-Codes submitted in the package. No major issues, just a few adjustments to placement on the printer board for the outer wing panels. Otherwise very well. I use a Prusa i3 Mk3.
    It assembles easily and it looks very good, very nice scale appearance.
    The flight characteristics are very good, the plane is stable and has very good handling with the settings suggested in the manual. C/G is 5mm behind the recommended setting.
    Battery is 3S-5000mAh. Motors and controllers as suggested, and the props are 9×6 CW/CCW. This setup provides ample power.

    Not so good: The plane has terrible sea-going characteristics. When applying power, the front of the hull digs into the water, sending LOTS of water-spray through the props and engine nacelles. After three consecutive take-offs and landings, water was everywhere in the front and centre fuselage and wings. It probably sloshed outwards inside one wing, causing the plane to roll over on its side during take-off and ending up upside down. Drowned the receiver and two servos. The motor-controllers survived because I sealed them with silicone in both ends.

    Conclusion: The Catalina is a very nice and well flying plane in the air, the scale appearance is excellent, but it has a terrible take-off run on water.
    It would make a very good land plane if fitted with wheels, or you can probably take off and land on grass with the hull only. It is also so light that hand launching should be no problem.

    Suggestions: Could it be an idea to stretch the front part of the fuselage lets say 5-6 cm to increase the float volume in front of the C/G? Some of the scale appearance will be lost, but maybe the sea-going characteristics could be saved? It is a too good plane to scrap only because of the water-spray problems.

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    AvatarJan Masek

    Hi bjofuruh – i had the same issue with the water spray. I added a piece of sponge to the entrance to cable tunnel in wings, added a small hole to bottom end of engine nacelles that the water is able to escape through there. Added sponge to the cable entrance that slows the water eventually blocks it. I’ve added some pictures to explain.
    I believe the spray is due to fuselage endings, I believe, the original catalina has this angle negative not 90 degrees. I believe that minor changes to F1 could help solve that. Also the addon spray rails could be angled and extended
    Few tips for water: use nanotech on your rx (disassemble and spray on), the same for servos. Silicone on ecs’s is not enough, use epoxy 🙂 Put your RX into a plastic bag, it blocks splasches. Add a piece of sponge to F2 area, any water that makes it there will soak on into it not moving all around …
    please redesign servo holders, hard to get there with glue gun to glue the servos.
    my CG is 10 mm further to tail.

    spray rails detail

    • This reply was modified 1 year, 7 months ago by AvatarJan Masek.
    AvatarJan Masek

    I’ve found a detail on spray rails

    AvatarMartin Klöpfer

    Hi Guys!
    Sorry for not answering the last days. I was on hollidays with my children and now I’m stuck with my other work.

    Nice build, and nice flying videos! 😉 Do you use video goggles for recording?

    Nice bulid as well! I don’t know what you’ve been doing to get that much water in the fuselage. The catalina tends to dig though waves in the transition between floating and sliding cruise, but even the original does that. Very most of the spray that hits the props will not go inside the gondulas. On all of my test flights I never had more than a few drops coming into the fuse even in rough water. Only when my canopy wasn’t thight. So, it is more likely that your canopy sealing isn’t good. I see that the front canopy screw is missing on your pics. This is where most of the spash water will come in. Did you use sealant tape at all?
    Maybe you could do some video of your staring issues…

    Like I said, I’ve never excperienced much water coming through the cable tunnels, but adding some piece of sponge in it and drilling a hole at the bottom of the gondulas is a very good idea! I was thinking about a spray guard when constructing, but abandoned that for mounting reasons. I am planning to do a motor mock-up for the next version and this might work as a spray guard.
    As I wrote in the guide, it is very important to use some wet protect spray (e.g. nanotech oil) on all of your electrical components. Believe me, I’ve been drowning more than one of the prototypes completely and never damaged anything of my electric equipment.
    HINT: I keep all the silica bags that come with the filament spools and store them in some tupper box. I put all sensitive devices that got wet in that box and allow them to dry for some days. I once even rescued my cell phone that way…

    I’ve been checking on the spray rails again. (Thanks for the photo Jan.) Seems that size and angle are quite correct according to the original. Actually I believe they’re more ment to tie the plane up than to protect from sprays. But I’ll size them up in the next version. (@Jan: how much did you add?)

    AvatarJan Masek

    Hi, the spray rail seems ok, have a closer look on the edge of the fuse. The line in cut goes almost horizontal and then drops down significantly before pointing up on the side of the fuselage. It makes a tooth on the outer edge, that is what would deflect most of water to sides. I hope that it is comprehendable ..
    I added 15 mm to front of the rail with no extra effect. It sprays from the edge not pointing up ..
    I would back bjoforuh feeling, that it goes through the tunnels. When I was making taxi tests, I glued the canopy by tape, a lot of water was in. No other way how to get there.

    AvatarJan Masek

    I made an exagerrated ilustration of the tooth. I believe on models we do usualy use 5-10 mm long rails, maybe if you add it more scalelike, that you can somehow make it heigher than it would be scale, but more funcional.
    I use just some gopro camera on headstrap. But it has a wide field of view – tends to make the plane small … good mobile phone with zoom and a cameraman is a better choice. I use this as a black box

    AvatarJan Masek

    I’ve made a prototype rails, I will let you know, how does it work ..

    AvatarMartin Klöpfer

    Hi Jan,
    looks good to me and will no be too difficult to change at the fuse. Let me know the results…


    Hi Martin!

    Very nice design! This might be my project for the winter.
    But are there more videos of this glider? I would like to see it in an aero tow and how it behaves in thermal flight.

    Maybe you can share your experiences?!

    AvatarMartin Klöpfer

    Hi apocalypsedude,
    I think your question belongs to the SZD forum.

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