flywise

From what I found out so far...The Amphibian and the catalina were originally set up to carry the 2 smoke rotax 582. That engine is extremely light (great power to weight ratio). In the last years of production avid had an option to install the rotax 912 UL (the engine mount on my catalina is made by avid aircraft). Some builders installed other engines like the  Rotax 618, Hirth F30, Hirth 2706, Verner 133MK and BMW R1200.

I believe you have to consider a couple of important design limitations when installing different engines on the catalina...

1. C of G consideration...if your engine gets too heavy you will have a too aft c of g...not a good flyer, can even become impossible to load properly without ballast (not good) 

2. structural limitations...if your engine gets too powerful or too heavy (over ~100Hp) you will need structural analysis for structure strength (including tail section being hit by a more  thrust/propwash)

3. aerodynamic changes...solid inflight testing for increased toque, Pfactor and high thrust line effects. Effects of flying above designed Vne? (rotax 912 cruises @Vne)

4. last and not least, the catalina is designed to fly, float and take off well at 1200Lbs. If you install more weight than a rotax 912 you will have either a 1 seat aircraft (less useful load) or fly beyond the designed specs....I found out that weight is the worst degrading factor....

To give you an idea, a rotax 582 catalina empty weight is about 600-680Lbs (520-600Lbs useful)

a rotax 912 powered (UL or ULS) empty weight is about 750 -850Lbs (350-450Lbs useful)

Any other 4 stroke engine will be heavier than the rotax 912 series...

Hope this helps to see clear in the mud

Not wanting to be a douchebag and criticizing good ideas for drag reduction but I would have a major worry about not being able to assess the condition of the struts, once these fairings are riveted and stuck on with tape and foam.

We are dealing with relatively thin walled tubing and it is not uncommon to find corrosion (maybe even more if you fill with foam). These struts are primary structures with very little redundancy...

Be safe my fellow flyers..

Hi Smartguy..

I have a set of WHLWI62L main wheels and in order to save weight and to make field repairs easier I ordered the oring/valve stem kit...well that kit does not fit! There is no provision to fit that o-ring.

I then proceeded to thoroughly clean the mating surfaces of the rims and made a thin fillet of M3 marine 5200 sealant around the mating surface - groove. Just enough to make it air tight but not too thick to prevent the rims to seat properly. Let it cure completely before you assemble the rims. I fitted a solid brass stem kit, sealed with the same sealant.

It has been one year now and I am happy to say there is absolutely no leak and it works great for me. I carry a motorcycle tire repair kit in the plane...takes 5 minutes to fix a flat if that ever happens. No more stupid tube removal and repair (ever tried to pry the rim off the tire in the field....a real PITA)

My 5 cents...

Hey Superavid,

looking at your tailwheel installation it seems you have a negative castor angle which is supposed to be bad (see the picture below). Did you try different angles (shims installed)

? What did you find?

Thanks for your input, Laurent

The Canadian avid flyer connection has sent you his small contribution..Thank you so much for keeping this up an alive

Hey northidahoflyer, 

could you edit the title please (rudder vs rubber) so that when we search for your post we'll find it in the future..

Thanks buckets

Hey guys, here a little unedited video of where I live and fly (or the other way round). Most is over the ocean but at the end is the Lake I land and take-off from (Sakinaw Lake) which is 15 min from where I live. 

Happy flying year to everyone...  

https://1drv.ms/f/s!AvMw5i-09AkLsHu7ia50rhW4jDyf

Have a look at this 3D printed strut fairing...really neat and light.

Here the full story     https://electricmotorglider.com/2016/04/22/emg-6-shop-notes-april-2016/

I don't know if it's me but that prop looks HUGE for the misery 65Hp engine....I know that running a slow prop speed the diameter has to be increased ... but to have a 4 bladed prop and such a big size diameter (looks like 69in) seems over proping the poor hirth

fantastic looking aircraft .

Hey Turbo,

funny you talk about inboard and outboard jury struts.....on my Catalina, Avid aircraft (or the CAA in GB) found they had to ad a jury strut because of the increased span (36ft)...The wing was not strong enough with only one jury strut.

Hey Guys 

I have been successfully operating a fibreglass spring on my Catalina. It saved me more than 2 Lbs of weight compared to the double steel setup and it does not sag as much/a bit stiffer which prevents my rudder to be hit (remember the Catalina is extremely tail heavy compared to the other Avids ....static, wings unfolded I have about 110Lbs weight but when I fold the wings the weight goes up to about 220Lbs!!!)

I was going to make a spring but did not have the equipment to prevent air bubbles between the layup ( oven and bagging technique). I found the easy way to by a 84-96 Chevrolet corvette rear fibreglass rear mono leaf spring. like this one on ebay 

https://www.ebay.com/itm/Corvette-rear-fiberglass-leaf-spring-84-85-86-87-88-89-90-91-92-93-94-95-96-NYU/372502247525?hash=item56badd3865:g:OcgAAOSw8PJb7Jlq:rk:8:pf:0

With it I cut 4 different length to make the perfect one having good strength, rigidity and rebound. I tested mine to over 2000Lbs no problem

See the picture of my tail assy below. Last picture is the before..

Hey Guys,

I am replacing my King Ky97 for a dual frequency garmin SL-40. The King comes with it's tray and is in good working condition. I can include a com whip antennae if someone needs it.

It's all yours for 590 $ + shipping

It could be carb icing depending on conditions and otherwise I would check for fuel contamination  going from tanks to Carb. (fod or water in tanks/gascolator , check carb fuel bowl (drain it) for contamination and fuel filter...).

My 2 cents

P.s I guess you did check the fuel tank drains for water/contaminants before flight/!

Note there is a special bulletin about water contamination in the Cessna 172...  https://all-things-aviation.com/tag/drain-water-from-airplane-fuel-tanks/

Hey Justin on the avid Catalina the wing spar had to be extended/spliced to make the span 36 ft. I am including the splicing method of the spar (from the Avid company) and it might be an option to repair your damaged spar... 

The flaperon being fitted with counterweights/balanced should just sit in a neutral position in the airflow....at least that's what I thought.

Anyone to shed some light?

I am very surprised that you would loose control when only one flaperon is connected to your stick instead of two. In my manual Avid states that you can control roll (if flaperons are completely u/s or disconnected) with rudder only. In the above scenario he still had one flaperon working + rudder!!!

Any thoughts?

If I was to choose a new engine I would go for the BMW R1200 engine. Parts are a non issue at a reasonable price. Here you have some info about a guy fitting it to a cherry BX-2..

http://spang-air.de/e/html/bmw_-_engine.html

Price wise you can get them at a good price too...

https://www.ebay-kleinanzeigen.de/s-anzeige/bmw-1200gs-flugmotor-m-neuen-bleidieselgetriebe/687835651-242-5976

Here a thread on homebuiltpanes.com

http://www.homebuiltairplanes.com/forums/showthread.php?t=4438

I would be against welding a cabin heat shield to your exhaust because there would be no way of inspecting it for cracks....danger of monoxide poisoning 

Hey Curt,

I understand you're at a high elevation and have not much useful load there....but looking a little further down the road, if one day you sell or the plane moves closer to sea level it is of GREAT value to have the possibility to fill more fuel.......One of the prime items a buyer is looking at is endurance .  I bought an Avid with 14 Gallons (only one tank in the right wing) and lowered the price because it takes a LOT of work cutting into the wing to ad another tank. I am very limited in range until I add the second tank because the Avid flyer fuel pick up is far from ideal. 4-5 gal in the wing tank is not enough to fly safe as you will constantly feed from your header when banking/climbing & descending...

My 2 cents

Hey Allen,

thanks for your input. My quote about 2smokes has nothing to do about them being good or bad....it's only financial!  

A 912 s is many times the price of a 582...so logically an amphibian fitted with a 912 is more expensive than when fitted with a 582.

This amphibian is fitted with a 582 and basic instruments (handheld VHF, no xponder) . hence my comment.

2 years ago I bought a very well built Catalina (evolution from the amphibian) fitted with a Rotax 912, in flight adjustable prop, panel mounted VHF and transponder with a purpose built trailer for 27'000....

Also not so long ago a complete catalina Kit was sold for 7500US..

My 2 cents....

I stand corrected .....thank you for shedding the light

Hey Northidahoflyer,

if it came off a pusher it will not work on a tractor configuration.....blades would be back to front. Hope that makes sense

Found this ad on barnstormers.....I wonder why someone would install wing fences on an avid amphibian? Price is quite high being fitted with the 2smoke I find.

https://www.barnstormers.com/cat.php?mode=search

very appealing paint scheme, I am sure you'll enjoy this bird. Make sure you got a good instructor though.

Just wondering what your empty weight is with the soob engine.....???

Hey , I am just wondering what impedance is best with the 912. Some caps are 1kΩ and the ones you bought are 5 kΩ....

I found this company selling caps for the 912 and they're 1 kΩ....

https://shop.brp-rotax.fr/en/all-rotax/12667-983409-shielded-spark-plug-connector-bosch.html