I have been building a 95" Beaver with floats and am wondering if with the floats generating a considerable amount of drag below the centerline of thrust if I should keep the usual 2 degrees of engine right thrust but decrease the down thrust to compensate for the drag of the floats.

I calculated the wing incidence at just under 2 degrees positive and the floats are 1 degree negative to the CL of the fuselage.
I built a fixture to hold the fuselage CL straight to my building surface and then set the float angle accordingly and then fabricated the struts.

This is a KMP ( ESM ) ARF that is a total piece of crap out of the box so I have made many changes.
The float struts were not in the scale locations and the floats were junk so I have grafted a set of H9 1/5 floats to the fuselage.
I have also fabricated scale float struts and reinforced the fuselage as needed. Fuselage came crushed by UPS so I looked at it
and decided if I had to fix the crushed FG fuselage, I would strip it down and build it right.

I threw out all the control surfaces and made new "correct" ones. The original ones were totally inadequate.
Wings have been stripped of covering and braced for better strength.

It has been 1 step forward and 2 steps back for 4 months now but I have all the bad behind me now and am getting ready to mount the engine.
I have chosen the RCGF "Stinger" 30cc twin gasser..............a super great running engine.

It has been a long tedious rebuild but I am ending up with a far better model and closer to scale.
I now know why KMP went out of business. I don't know how they sold these ARF's.
Worst I have ever seen.

Originally Posted by High & Mighty

What do you all say about my question concerning engine thrust settings?

Looks like it's been a couple of days, so I'll jump in ... the Beaver looks very similar in layout to my Sig Kadet Senior, which I regularly fly with both floats and wheels. IMHO you shouldn't bother changing the thrustline because the difference is small, just a couple of clicks of elevator trim going between floats and wheels. However, if you don't ever plan to fly without the floats and the model has downthrust built in, you'd probably be OK taking out the downthrust. In fact, if I were in your shoes, I might also take out the right thrust. Right thrust is for airplanes that are marginally powered and flying upright more or less exclusively, a situation that makes the torque and P-factor more significant than would otherwise be the case. If you've got adequate power to create a good breeze over the tailfeathers and if you plan to do any aerobatics, thrust offset will probably turn out to be more trouble than it's worth. However, I hasten to add that I've never owned an actual De Havilland Beaver, so there may be something about this design that makes it need right thrust. So please take my comments with however much salt is appropriate.

Looks like you're improving that airplane quite a bit. Good luck getting her out on the water & please keep us posted!

Cheers,
Duane

Thanks for the reply.......and a good one at that!
The firewall checks to have a minimal amount of right and down thrust and I am guessing that is to ensure it does not have any of the opposite. My plan is to fly it in a scale manner as intended. Maybe a loop or a roll but nothing crazy. A dedicated floatplane.......never on wheels.
I am replicating the exact same Beaver I used to fly in as a younger man on fly-in fishing trips in Ontario. My Dad met the owner when he was a young man and they became good friends. The pilot was from southern Kentucky and had a life lease on the property his lodge sat on. First time I went up was in 1967 and we used to fly back into trial lakes and drift across the lake while casting off the back of the floats to see what was hungry. If it was a good lake he would drop us off with 2 tents and come back the next day with a 14' boat slug under the plane on the spreader bars and a 4 HP Johnson outboard and 5 gallons of fuel. We usually set up camp on an island as to not have to worry about bears and flies. Ever tried to pitch a tent on solid rock?
Much has changed up there now. The pilot and my dad have both passed away and I have located the old Beaver in Sault Ste Marie in dry storage and for sale.

The manufacturer's serial number on the plane is #59................ License number C-FOCT

Awesome story, thanks for sharing! One of the high points of my life was a canoe trip in the Quetico with our scout troop in 1971 ... 5 days and we never saw another soul except on day 3, two canoes at the far end of Lake Agnes. There were bears, though! The outfitter had a Beech 18 on floats, what a show when that thing took off. Nothing beats a Beaver for noise & smoke, though.

Looking forward to video!

My experience is right thrust is needed in most models. The torque of the engine and the slipstream of the air going over the fuse and rudder will tend to make a model bank and turn to the left when under power. I agree you might not need any down thrust because of the drag of the floats but I would definitely leave about 1 or 2 degrees of right thrust, at least until you fly the plane.

nice looking project!
Where did you fly out from/to in OCT? A buddy has beaver OCP, same era of beaver Those old ones never had the porthole window in the back till a bit later of a serial number. Some were likely modified with it.
Your float struts look very nice too!! Please though, make your water rudders retract. Taking off and forgetting to raise the rudders costs the pilot a case of beer!! I've paid my share over the years

I ordered a set of retractable water rudders from MR Aerodesigns in Ontario.
This guy has one of the nicest Beaver kits I have ever seen and some nice accessories too.
https://mraerodesign.securicom.ca/en/

I flew out of the Chapleau area with Lee Cole. Lee pissed a lot of city slickers off that came up his way expecting to be pampered and baby sat. He was the pilot....he made the rules. If you didn't like his rules then you would be best to leave. We always got along just fine!!!!!

Engine installed last night.................Fits nice.........looks nice....at least I think so!

Here is what I am shooting for for the final build.
Both are great shots and second shot is power on but not on step yet.

These pictures are lifted from Air-Dale out of WAWA but this is Lee's old Beaver with fresh paint and upgrades.
Lee lost his physical in 2009 and retired at that time. His lodge still operates by family but no flight charters.

It was a very different world in that area over 50 years ago.

Update: I have the airframe completely disassembled and have applied polyurethane primer and a base color coat of strobe white Polane B to the FG fuselage and cowl. The humidity is high and I had to wet sand due to some orange peel so I am waiting for dryer air to apply the final sheen coat of white and color trim. This is not a automotive basecoat-clearcoat application.
Polane Urethane paint tends to go on heavy and then flow out to glass IF the temp and humidity is correct. Gotta be careful with paint......you can add a lot of weight if not careful.
I must brag here...……….my repairs to the UPS crushed fuselage came out very nice. It has been a 4 month ordeal getting it straight and smooth.
From my experience I believe that the Sherwin-Williams "Polane B" is the exact same as Klasscote and it is fully compatable as to paint and reducer.

Correction.......The Polane is Urethane and the Klasskote is epoxy but compatible to paint one over the other once cured.

I started this discussion with question for engine offset and then showed pictures of what I had for an airframe to start with and photos of my subject to replicate. I have been a "Busy Beaver" myself since last November when all this started. A crushed model left at my door by UPS.....followed by anger, frustration, and then the feeling that I wont let this beat me and the decision to repair the airframe and make it into something that the original ARF never was. Here are the pictures I have been waiting to post. Not done by a long shot but feeling good about where I started and where I am now.

When I say crushed......I mean crushed. The whole right side and bottom of the fuselage looked like it had been punted from the 50 yard line.
I had to cut the fuse apart and re-align it in a fixture and then glass it back together from the inside out using West Systems epoxy. The right wing was also crushed and rebuilt. All control surfaces have been replaced and correct undercarriage installed.

I have grafted Hangar 9 floats and stripped the iron on covering and will be glassing them also and adding sub-rudder to fuselage.

White paint is Sherwin-Williams Polane B urethane and the Flame Red is custom mix KlassKote to match the Ultracote covered wings.
All windows appear to be blacked out in photos but they are actually just smoked gray and transparent.
Finish it up with a scale dummy P&W Wasp radial (RCG Jiri Prekin) and retracting water rudders..........should be a winner!

I am proud as a peacock on this project...…...one of a kind!

Dummy Radial installed with pushrods added.
Really not decided on how far to go with engine detail.
Can't see any of that fine stuff when it's in the air.

My shot from 1968 looks to be more reddish in my memory..... and weathered.
Correction..............the photos on right are from 1973 on Frechette Lake, Ontario.
Frechette had a dam on the north end and the water level was down about 4 feet.

Got the floats completely glassed this weekend and did a CG check.
May have to use a different engine for weight.
I have a Webra Bully 35 cc NIB that I just finished the conversion to Rcexl ignition.
It is about a pound heavier than the Stinger 30cc twin but the Webra's run so nice on gas/ ignition.
I love the sound of the Stinger twin though but the carb is finicky. Very touchy needles.
Going to bench run the Webra Bully this week. This is my 9th gas conversion on a Webra.
Excellent German quality and very well balanced for a single cylinder....Oldie but a Goodie!

Your Beaver looks amazing!
Did you fabricate your float struts, they look killer! If so, how?
I am in the process of converting a 40 size Goldberg Cub to floats and I am using the same floats with the supplied struts. You mentioned that you glassed your floats. I pulled the covering of and sprayed multiple coats of spar varnish on my floats. I’m hoping this will negate any potential leaking, I will also recover. Being a smaller aircraft than your Beaver do I need to cover in glass? I sure you saw the forward section ahead of step is plyed and glassed, do I need to do more?
Can’t wait to hear how your Beaver flys!

Thanks for the compliment!

I located where the scale hardpoints for the struts should be and made machined aluminum cross bars that went through the fuselage then located the hardpoints on floats. I then made up a fixture to hold the fuselage in relation to the floats at the correct angle in relation to the centerline of the fuselage and the step in relation to the CG........Did a lot of calculations and layout drawings! The floats need to be 1 degree negative to the CL of the fuselage........float tips down in front.........never tips up!
Once I got the fuselage and floats in position and the spreader bars the correct width, I started making the struts out of 3/4" heavy wall K&S streamlined aluminum tube with 1/4" diameter aluminum solid rods down the middle and machined the ends to bolt up to the cross bars in the fuselage. Once everything was in position I then, for my last step, reinforced the crossbars in the fuselage with heavy fiberglass unidirectional mat. I would say I have about 200 hours in the fuselage rebuild and float mounts alone. Everything is either aluminum or 316 stainless steel. It is very solid and needs to be. Tools required...........a nice machine shop!!!
I always glass the floats. They are stronger, more durable, and less prone to leaks but you always have to keep weight and strength in mind. Glass does not get "sun warts"!

I will post more pics when the floats are painted and remounted.
I also have to install the retractable water rudders before remounting the floats.
Might be a while and may have ice on the lakes by then!

Wow impressive! I’m not quite there yet. Refurbishing a 27-year-old Goldberg Cub, turning it into a float plane. Only started flying RC in May, long story as to how come I have such an old plane.
Probably won’t be able to get mine on the water before the snow flies here in Northern California, something to look forward to in the spring.