Author Topic: PBY Catalina + Saito .40 x 2 = SUPER CAT! (Read 4469 times)

wwwarbird · « **on:** April 19, 2010, 01:57:32 PM »

FINALLY! While fighting it all of last season with the Saito .30's the PBY just never quite got there, real close, but just not there. I could tell the airplane had good stunt capablility in it all along though. It has tracked dead straight without a sign of a hunt and was very stable from the very first flights. During the season I tried literally every prop, fuel and RPM combo you can think of, but never got any real strong authority with power. Only ever enough to do big loops and lazy wingovers with any real confidence. The reality is that we're talking about a plane with just over 700 square inches, weighs 80-82 ounces, all with a design that has a lot of built in headwind.

During this past winter I decided to make the swap to Saito .40's. The thinking was that besides adding .15 cubes per engine, I would also be able to take off some of the dead nose weight that was needed for balance with the .30's because the .40's are heavier. I would also hopefully be able to go back out on the line length a bit, I was all the way down to 60'.

The first flights with the .40's was yesterday at the Piston Popper club field in Minneapolis. WOW!!! What an incredible improvement! Every theory going into the swap worked and then some. I can now honestly claim that the PBY is a full blown pattern capable stunt model, and a pretty good one. The first flight was about a 1000% improvement right off the bat. I started out with Master Airscrew 10x7 three blade props, Sig Champion 10% nitro fuel and launched at 9400 RPM. It ran a consistent RPM the entire flight with plenty of power giving 4.9 to 5.0 lap times on 62' lines. I flew one more flight just to get the engines synced a little better and could already tell this thing was ready to go. Since I'm not a fully pattern capable pilot, I put Keith Sandberg on the handle next without changing anything else. He's a consistent 500+ point threat and has plenty of twin experience. After a couple lazy horizontal eights to make sure it would stay running ok inverted, he started putting it through the paces. On his first flight he did basically every pattern maneuver. The plane handled it all with ease and didn't give a wiggle anywhere. NOW this is fun!!!

Willis Swindell · « **Reply #1 on:** April 19, 2010, 02:54:31 PM »

wwwarbird

How much fuel are you using? It looks like you could squeeze a 11 inch prop on it . After the Huntersville contest I am going to get back on My Heinkel twin. The first props I want to try is a Master Airscrew 11x7 three blade cut 1/4 inch at the tips Keep us informed on your progress.
Willis

Karl Knipper · « **Reply #2 on:** April 19, 2010, 03:04:25 PM »

Nice looking Plane, I,m sure its a fun one to fly.

Glenn (Gravitywell) Reach · « **Reply #3 on:** April 19, 2010, 04:03:07 PM »

Congratulations on your acheivement!

How about a few more pics just for fun?

Paul Taylor · « **Reply #4 on:** April 19, 2010, 04:49:55 PM »

That is just too kewl!!!

Dalton Hammett · « **Reply #5 on:** April 19, 2010, 05:50:03 PM »

Great looking plane and quite an achievement to make a stunter out of it.......................................

Dalton H.

Mark Scarborough · « **Reply #6 on:** April 19, 2010, 06:10:15 PM »

REALLY glad this played out well, now go get a brodak p-40 arc, and learn the pattern so you can show off this beaut!!!!

proparc · « **Reply #7 on:** April 19, 2010, 07:14:15 PM »

I've said before, and I'll say it again-I seriously love my Saito 40A. I consider it a modern day version of the ST 46. And since I happen to own both of them, I made a point to test them side by side.

Saito 40A Rocks!!!

Martin Quartim · « **Reply #8 on:** April 19, 2010, 07:23:38 PM »

Awesome! I just luv Warbirds Stunters with a 4 stroke, with two is even better. Please make a video !

Martin

wwwarbird · « **Reply #9 on:** April 19, 2010, 08:35:10 PM »

Willis,
With the current settings and 3.5oz tanks I was getting just a shade over 7 minutes total run time with each engine. They were running very happily with plenty of power but I do need to record some more detailed info on the settings. The first flight was launched at 9400-9500 RPM but there were a couple very slight needle adjustments between flights to sync things up that I didn't tach. I didn't even bother trying different props because it was working so well. I don't have room for bigger props, with the 10" I've only got about 1/2 clearance to the fuse.

Gravitywell,
Check the posts "Picture posting test (PBY Catalina Stunter)" and "PBY Stunter?" here on the Open Forum and you will find a bunch of pics of the build and the finished model.

Mark,
I actually have a Brodak P-40 ARC kit on the shelf, it's on the "To Do" list.

Mark Scarborough · « **Reply #10 on:** April 19, 2010, 08:44:55 PM »

Wayne,
remember the sage advice of the designer,, ( and me, and others) add the dihedral, it will make a difference. Its a really sweet machine and one which has given me TONS of confidence
I did a photo thread a while back on how to do the dihedral, its really easy, takes me about an hour start to finish

John Miller · « **Reply #11 on:** April 19, 2010, 08:50:02 PM »

Way ta go Wayne. The Cat rocks

wwwarbird · « **Reply #12 on:** April 19, 2010, 09:27:04 PM »

Here's a picture a few people may like to check out. For the moment forget about the PBY part, just think airplane. You can't quite tell it here but the wing, stab and thrust line are all on exactly the same line with this model. The leadouts are adjustable both horizontally and vertically. When designing I estimated that the leadouts would end up about 3/4" to 1" below the surface of the airfoil in final trim and I mounted the bellcrank accordingly. When bench trimming before the first flights I found this to all be very close when hanging the model by the leadouts. Since this photo was taken I've modified the vertical portion of the adjuster to be able to raise it a bit more. The leadouts are currently running 5/8" below the wing at the adjuster and the plane flies wings level. I've never touched the adjustable trim tabs that are part of the flap and move with it. In case you're wondering, that's a 60" one piece flap. About the only design change I would make on another one would be to move the bellcrank mount up just a little.
The main point with all of this is that with the leadouts placed properly, it flies like any normal airplane. It does look really weird out there though, and man does it pull!

Bob Reeves · « **Reply #13 on:** April 20, 2010, 07:51:10 AM »

Really cool, glad you hear you are happy with the Saitos, sounds like you are running in the right RPM range. I can just imagine how much line tension you have. LineII says it's about 16.75 pounds.

Tom Niebuhr · « **Reply #14 on:** April 20, 2010, 08:24:24 AM »

Wayne,
That is a major accomplishment! Congratulations.

Bill Little · « **Reply #15 on:** April 20, 2010, 08:51:52 AM »

Hi Wayne,

The model is awesome, and I am glad you have found a good working power train! This model should give you many happy flying sessions.

In case there was any confusion, I am pretty sure Mark S. was talking abut the P-40 ARC needing dihedral, not the PBY. Disregard if you already knew that!

Big Bear

wwwarbird · « **Reply #16 on:** April 20, 2010, 06:14:24 PM »

Thanks for the comments guy's, this ones been a lot of work!

Bill and Mark,

Nope, PBY's don't have dihedral. I do remember all the talk about adding it to the Brodak P-40. I think some others just moved the wing up didn't they? Either way, whenever I do build the plane I plan to make up completely new fuselage. I'm not so sure it will even be a P-40, that would be way too easy!

Harleyman · « **Reply #17 on:** April 20, 2010, 07:46:02 PM »

Way to go Wayne. It looks great! I'm glad to hear it performs as well as it looks.

john e. holliday · « **Reply #18 on:** April 20, 2010, 09:17:53 PM »

Wayne, glad to hear it is working for you. That has to be quite an undertaking and I admire you for that.

Will Hinton · « **Reply #19 on:** April 21, 2010, 03:55:19 PM »

That is one AWESOME bird!!!!! I've threatened to build one for scale competition for years, now you've inspired me. Problem is - I think I'd rather do the stunt version like yours!!!! You rock!
Will

James Lee · « **Reply #20 on:** April 22, 2010, 08:44:51 AM »

Wayne
Looking forward to seeing th 'Super Cat' at the Sig contest!!

Jim

wwwarbird · « **Reply #21 on:** April 22, 2010, 08:50:43 AM »

It'll be there. I'll have to talk Keith into putting up a demo flight or two to show that it is capable. I'll be flying it for fun too, but Keith can give it a better workout than I can. Friday evening is usually good play around time at Sig. Heck Jim, you can take it up if you want to, I'd be honored!

proparc · « **Reply #22 on:** April 22, 2010, 10:53:06 AM »

Two 40A's-man I want to get a flight on this plane sooo bad. You have got to find a way to post a video.

Garf · « **Reply #23 on:** April 22, 2010, 11:18:54 AM »

Quote from: proparc on April 19, 2010, 07:14:15 PM

I've said before, and I'll say it again-I seriously love my Saito 40A. I consider it a modern day version of the ST 46. And since I happen to own both of them, I made a point to test them side by side.

Saito 40A Rocks!!!

I don't suppose the mounts are the same?

Author Topic: PBY Catalina + Saito .40 x 2 = SUPER CAT! (Read 4469 times)

Willis Swindell