Hi Nick,

I have just been out to check the size of the prop that I am running on the Remora and it is a standard size 45S.

As for duration with the shown 5000 mah pack, it sips so little power I have never been able to run the LiPo down far enough for the ESC to cut in!

By way of comparison, the same motor with a 50X prop in my Rapier with a 7600mah Overlander LiPo will give 10 minutes (maximum) or less!

Bob.

Hi Bob, just read through your build log - another great Vic Smeed design I've read about, although I've never seen one in action until your very impressive video. I'm particularly interested in the fact that your chosen motor, a 3536/6 1250kv Turnigy Aerodrive is almost identical to that which I have in a David Boddington Ghostrider 50 aircraft, a design from 1974 that was also for .20 sized glow engines; mine is the 3536/8 1000kv turning a 10" x 4" prop which allows the aircraft to perform very well. My point here is that this size of brushless motor and its kv rating matched with your 3-cell lipo gives me a starting point for working out glow engine to brushless power conversions (remember our Vivacity/Beachcomber power system conversation😉)
An OSmax20 kicked out around 0.5 hp at max power (373watts), so your Turnigy (rated at around 500watts max I believe) is an excellent, slightly more powerful substitute. Your kv rating gives around the same max rpm of the glow engine (15000rpm at 12v-ish). What size boat prop do you use in Remora? Also, what kind of endurance do you get with the 5000mAH pack?
Matching the power in this way certainly seems to work for higher speed planing hull sport designs, just need a bit more of a guide with prop selection I suppose.... Vivacity could be a bit different, requiring a smaller prop than the original 3" diameter which ran off similar power output to the max of the OS20, but at around 1/5 of the rotational speed at max power because of the torque of the JAP34cc engine.
Really interesting to see the construction of your Remora at the bow - like the way the curves were carved from layered block, rather than 'forcing' the shape from the ply skins - a very practical solution.
Going to start looking around online for larger brushless options with lower kv ratings...

Nick

Didn’t think this simple build warranted a full build log, so I just added some pictures to illustrate the main stages of construction in the hope that it may encourage others to build their own Remora and enjoy it as much as I enjoy owning and driving mine.👍

Bob.

An inexpensive water cooled motor mount was used to allow for rapid adjustment or exchange of alternative out-runner motors, and this proved to be very handy when I had problems with the ESC .

I was able to swap motors quickly and identify the problem was not with the motor .

This particular engine mount leaked - even though I had fitted the the inlet and outlet nipples with 24 hr Araldite - it leaked out of its main casting -!!!!!

A replacement mount will be slid in between the glass fibre cheeks that are permanently mounted in the hull, but for now I have put a tube between the two nipples and bypassed the mount by exiting the cooling water from the ESC directly out though the cooling outlet in the side of the hull.

Bob.

A small shelf was made to fit the Seaking ESC under the rear deck against the rear of the engine bay bulkhead and a frame was made to drop the chosen LiPo into.

A little platform was added to secure the receiver with an elastic band so like the ESC both are held above the hull floor to help keep them dry from any minor water ingress.

This more or less finished the build of my second Remora (the first one was built from the same free plans in 1964!).

The Remora is a very simple little classic model power boat that is quick and easy to build and is great fun to run.

Bob.

The Remora is a very plain looking boat so I decided to add some detail to give a little individual character to mine.

I cut a narrow trough into the rear of the cabin top to sit a wind deflector screen and a small mast into.

I bend some brass wire to form a pair of grab handles on either side of the cabin rear….even though there is nowhere for a model driver to stand !

A hatch with two doors and a dummy air intake was added to the rear deck to help it look less like a sandwich box.

I am not too sure about the engine air intake, but the hatch looks OK.

Bob.

The rear hatch is simply covered with a balsa wood plug that has a 1.5mm plywood skin cover fitted slightly wider than the plug to stop in falling into the hatch opening.

I chopped out the middle of this thick balsa wood plug partly to save some weight, and partly to save some of the balsa for future use!….I did the same with the first layer of the cabin top balsa sandwich.

In both cases, the balsa wood block was made in two halves making it easy to make the cut-outs and reducing the cost of the balsa wood as it was less expensive to buy narrow planks than wide planks.

Joining the two halves was easy as the plank edges are nice and square so they were glued with PVA and held together on a flat surface with masking tape tape to hold them together until dry

The basic assembly of the Remora is now complete and only needs final finishing.

Bob.

The simple cabin was put together using plywood and more scrap balsa wood.

Once the aliphatic glue had dried the balsa roof top was sanded to shape.

Bob.

Some foam was fitted into the bows to give some additional buoyancy in the event of suffering any crash damage and the deck skins were fitted.

Bob.

Once the prop shaft and motor mount has been made the side skins can be added. These shapes were also worked out using old card packets to make a template before being cut out from 1.5mm plywood.

The scrap ply that I used to make the transom from was so rough, I also covered this with a plywood skin to tidy it up !

The rudder and servo mount were also fitted at this stage.

Bob.