Catalina weight and balance


15 posts in this topic

Posted

Hi everyone....especially Catalina/amphibian owners. At last my catalina (after some modifications targeting weight) has made it onto the scales and I am shearing my figures.....I also would love to know the other member's aircraft  total empty weight and c of g position (please include setup setup engine/prop).

My Catalina (rotax 912 with GSC 2 bladed variable pitch prop, xponder, vhf etc) has lost 20Lbs....and now is as stated below:

Empty weight : 776,2 Lbs

Aircraft c of g pos ; 22,59 in

Fore/aft limit used :  most Fwd 11in / most Rear 17 in

 

Also could you share what fwd/rear limits you use.

 

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Posted

How did the CG wind up at 22" ? 

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Posted

Id imagine that's empty cg .the pilot passengers are quite a bit in front of the wing

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Posted

Dynomike, you got that right......the 22,59 in is the empty aircraft C of G

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Posted

The 22,59 inch c of g is measured from the datum (wing leading edge) going backwards towards the tail. It means when the aircraft sits empty on the ground it is quite tail heavy (normal for a pusher). As all the load put into the aircraft (fuel & pax) is forward of the 22,59in it will bring my  Catalina once loaded within the 11-17 inch range. Hope that's clear as mud.....

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Posted

Copy. I forgot to factor in the config of the Catalina. 

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Posted

Hello everybody......I am wondering if W&B is a secret thing......nobody to chime in???? What is your empty weight, C of G and configuration????

Also the book says the fwd and aft limit are 11.185 and 16.5 but my Catalina was approved at 11.0 / 17.0.....any thoughts? In my manual a handwritten statement says Dean Wilson states 11.0 / 17.5

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Posted

I do not have my paperwork in from of me for what the original builder has for the W&B on mine.  I am still doing the rebuild and have never flown it so I don't have any updated numbers for you.  I am pretty sure with the 582 it was right at the 600# empty weight.

I talked to Dean about the CG on the Avid Flyers and he said I could go back to 19" with no issues, I have flown it there and its great empty.  I have mine now where its at 18" and it flys much better than when I originally got it and the CG was at 11.5".  With having never flown the catalina I could not tell you how it behaves with the more rearward CG, but if Dean said you could go 17.5 I would bet that is still pretty conservative.

 

As always, pics of your plane and flying lies are always much appreciated!!

:BC:

 

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Posted

I would love to look at a 600# Catalina and see how it's different from mine.   Your performance must be incredible!  I'm at 746#, 25.07" CG.   That's 582 grey head, after significant work to bring it down from about 830#: fiberglass flaperons, fiberglass floorboard, rear seats & floorboards stripped out, no cushions, oil injection and tank removed, 2 pound LiFe3 lithium starting battery, aluminum tailwheel spring, water rudder removed, completely required with thin-gauge wiring, etc, etc.   

 

 

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Posted

And I settled on testing a CG range of 11.185 to 16.75. My plots of stick force and stability showed that it could go a bit more rearward, but I have no need to explore that unless I start losing weight. :) Or get a heavier tailwheel setup.

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Posted

Hey cowlove....great info here. I also would love to see how to get down to 600Lbs....sounds crazy low weight. I really would like to know more about your aluminum tailwheel spring as I am in the process of adapting a carbon/fibreglass spring.....

Did you make the spring? What weight? Is it strong enough (should hold at least 500Lbs )?

 

Thanks for your reply

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Posted

I did make the spring.  I just ordered some flat bar aluminum, did some back-of-the envelope calculations to design it for about the same ultimate strength as the steel spring, tested it, and called it good.   It has much less energy-absorption than the steel spring did, and of course there are big drawbacks to using aluminum in this fashion- it's almost an unsuitable material for a spring.  I wouldn't recommend it.    But it's just a placeholder until I can lay up a proper fiberglass spring this winter.  

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Posted

I was in the process of laying fibers for my spring when I read a post of someone doing the same with great difficulty (hard to gauge the amount of glass to get yhe right strength & stiffness)....he found a second hand  leaf spring already made from a chevrolet corvette C5 for 70 US. I just bought one for 60 US on ebay. I will have to cut the leaf spring to size. I will make a separate post for this one when I am done:)

 

Cheers, laurent

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Posted

I was in the process of laying fibers for my spring when I read a post of someone doing the same with great difficulty (hard to gauge the amount of glass to get yhe right strength & stiffness)....he found a second hand  leaf spring already made from a chevrolet corvette C5 for 70 US. I just bought one for 60 US on ebay. I will have to cut the leaf spring to size. I will make a separate post for this one when I am done:)

 

Cheers, laurent

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Posted (edited)

Grove was making aluminum tailsprings for Kitfox at one time - I think I still have one - I planned to make a tailskid out of it.  My Kitfox 3 had a 3-leaf steel spring on it - probably with the original kit.    EDMO

Edited by EDMO

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