Tomcat

Iconic aircraft. Dehavilland bet the farm on it being successful at a time when that was contrary to opinion. Brave decision, but it paid off in spades !

I had no inkling when I came up with the bright idea of building a set of floats how complicated it is ! It has taken me all day to get the geometry right & tested what little patience I possess to the limit. I got there in the end though! I have increased the size of the tail fin & rudder & added a small strake underneath for good measure. Lot's of sanding on the horizon for tomorrow !

Blimey Crash, that's bloody lovely mate!!!

Difficult to be tell from the picture but I wonder if the float step is a bit far back on the Tomcat.
The conventional wisdom is CofG needs to be not far in front of the step so it is easy to 'rotate' to leave the water. Similarly on landing it is important to be able to keep the nose of the floats up until it stops planing and the float becomes a boat.
A side view of a DH Beaver on floats.

It is reasonable to assume the CofG is on or close to where the wing strut joins the wing.
Note the float step is not that far behind the CofG.
How does this location compare to your Tomcat?

I suspect on a model with plenty of power the take off is not the problem apart from keeping straight but landing is a different matter.
It is worth noting that the initial motor torque will tend to depress the LH float and raise the RH one. Water drag is directly proportional to displacement unlike a wheel where rolling resistance is much less sensitive to the load carried.

I think it's the angle of the photo giving a false impression Q. The step is 1/2" behind the CG, according to the plan. It will be interesting to see how she floats, that is if I ever get them finished. The lacquer is taking forever to dry due to the weather ! I couldn't start sanding today so I started on the water rudders. After a lot of umming & arhing I've decided to stick a 9 gram servo in one float to drive them. I am trying to make them as easy to swap out for wheels as possible, as it stands there are only five screws & its done. If I stick a Y lead permanently on the rudder servo, one end can just sit inside the redundant battery box in the bottom to be connected when the floats are on. I should be able to run the wiring through one of the struts. Well that's the plan anyway.
I have also been swatting up on the flying side. The general consensus seems to be; Nearly full up elevator & advance the throttle "smoothly" to full, once planing ease off on the elevator a bit until she lifts off, simple ! Landing, well I will worry about that when I get to it, It's coming down one way or another !

Yep. It will always land itself if you let it

Klipkopwildlife wrote: One thing that can catch you out when landing on water is the lack of turbulence.

Thanks Klippy, iv'e not heard that mentioned before !

"water friction does the rest" can also be a problem if the landing speed is too high.
Water resistance is proportional to at least the square of the speed. The bottom of the floats touch first and are lower down than a wheel so a 'fast' landing with floats is much more likely to result in a nose over than with wheels. Furthermore unless you have divine powers you can't just walk over to pick it up!

Quorneng wrote: "water friction does the rest" can also be a problem if the landing speed is too high.
Water resistance is proportional to at least the square of the speed. The bottom of the floats touch first and are lower down than a wheel so a 'fast' landing with floats is much more likely to result in a nose over than with wheels. Furthermore unless you have divine powers you can't just walk over to pick it up!

That all makes sense. I know that our RIB can go from 35 knots to a standstill in a very short distance if you chop the throttle. As soon as it falls of the plane the bow digs in quite hard. The knack then is to do a hard 90 degree turn to avoid the stern wave catching up & filling the back with water, something that regularly catches out new recruits ! Not something I will be trying with the Tomcat though! Letting it "settle" gently seems the way go. I think I might invest in some waders.

Sorry to disagree Klippy. Turbulence does not stop... it affects the flying model till the model stops.