Forum

Graupner Closing

Sad that their components will no longer be available - the geared motors sets - the outboard motors - propellers - etc etc etc . All very useful items to say nothing of the kits they produced. Wonder how much the closure will affect the model aircraft fraternity?????????

4 years ago by redpmg

Blog

SEAPLANE TENDER STAND ADDITION

Not much to add really, just made a drip tray on the back of the stand for the prop . They are ball bearing and weep quite a bit of oil, (a good thing as it cleans out any water)

5 years ago by jbkiwi

Forum

Help required

Seriously though folks😁 Marky, there are dozens (hundreds?) of variations on the 540/545/550 theme 🤔 I have a pair of original standard ancient Mabuchi 540s in my 1.35m destroyer and she goes like stink on 6 to 12V. Makes a lot of RTR plastic "speed boats" look downright daft😊 Once upon a time the 545 was simply a 5 pole version of the cheap n cheerful 540, which gave smoother starting and better low speed control and torque. Nowadays there seem to be endless variations of both 540 and 545☹️ Very generally speaking the 540s seem to be higher revving and the 545s seem to have more torque. So look at the specs / price before you buy! More important is the size, displacement (hull type) and probable weight of the boat you want to shove around. For a tramp steamer obviously a displacement hull designed to carry weight so I would go for a low revving high torque version. Re shaft and prop; again hull type, size and weight of the boat are important factors. More so than the length of the shaft. In my 52cm fish cutter I am using a 3mm shaft and a 30mm prop. Much bigger / heavier than that (or higher revving motor) I would use a 4mm shaft I have some 1.5m warships where the load is shared by 3 or 4 so they also have 3mm and 30 or 35mm props. are also about 10 to 12" (25 to 30cm) What size prop is stated on your drawing? The larger your prop and the more power you are putting into it the more robust (thicker) the shaft will need to be. My 24" Sea Scout, with a powerful brushless motor and about 260mm shaft has a 4mm diameter shaft and 35mm prop. Cheers, Doug😎 PS Another example folks of where not all the necessary info is given to enable a definitive answer!

5 years ago by RNinMunich

Blog

Dang it!!!!!

Hi y’all. Been a bit since I posted anything on the Jeep. Did a test run on the motor and shaft, sounded a bit “buzzy” at mid throttle but smoother out in low and max power. Then, I installed the prop, and tested again..this time, I thought she was going to vibrate to pieces, and the amps went wayyy up. I tried reinstalling the motor, checked my coupling motor and shaft alignment, all looked good. Then, when I had it a low throttle, barely “ticking over”, I noticed the prop was a little..wobbly. On close inspection I found that the shaft was slightly bent right where the threaded portion ended, causing the aft end of the prop to rotate out of round by about 2mm. Now, I don’t have the tools to really straighten a shaft this size and get it dead on, so I looked the shaft over, found the bend, put it in my vise and gently bent it in the opposite direction. I got lucky as subsequent tests showed I was on the right track. Much quieter, very little vibration and the amp draw diminished dramatically. But, it’s still not right. Usable, but not dead straight. I found a vendor on eBay with 3mm model boat that are threaded, so I’m waiting for that to arrive. Once it’s here, I’ll cut it to size and retest. I did get the upper railing made up and installed, did a combo of soldering the easy joints and ca’d the rest. I also got the towing bar and gear built, painted and installed.

5 years ago by Cashrc

Blog

Stern Module assembly

This weekend I decided to do more work on the Gato Submarine. Now I am starting to realise how big this job to build the model is, let alone the WTC which I am thinking about and starting to plan in tandem. I have been working on the stern module today trying to get the rudder and aft planes in a working state. I have followed the video made by a kind soul on the internet which I am finding very helpful. To make them fit properly has resulted in a lot of filing and reshaping particularly on the rudder. All of the edges were interfering all over. After a considerable amount of adjusting, they now fit and work perfectly. A hole was carefully drilled right through the height of the rudder to allow for a shaft to be inserted for operation. Small holes were also drilled through some waste material to produce two running bearings for the rudder shaft. There has had to be a considerable amount of material removal inside the stern module halves to allow for the planes and rudder to work. This was done using a burr in the Dremel and files. Great care was taken not to remove too much and go right through the part. I am having a little problem with warpage of one of the stern halves. You can see the gap between the parts in one of the photographs. It might be that they will glue together without incident if I fix them well with bands during curing. Does anybody have a cunning plan to straighten this part before gluing? I have purchased the propeller and tubes so further work on this module will continue when they arrive, probably towards the end of July. I have now purchased my chosen motors. They are MFA 360. I have also ordered the raw materials to make the motor mount and servo trays. I wonder if I have to put the usual three suppressors on the motors if running a 40Mhz transmitter. Next time I am going to work on the bow planes. I will have them working and retracting. I bought the gears for the retracting mechanism today but have found them to be too big on diameter to fit two side by side in the bow module. The gears are perfect in every other way so I think I will reduce them to quadrants which should fit nicely. More cad design work for me I think.

5 years ago by MouldBuilder

Blog

40'' Seaplane Tender, new build D

Motors I'll be trying in the ST are either the 'Gool' (black motor) 540 (replaceable ball bearings and brushes and adjustable timing) or the Feilun boat spare 540 motor complete with mount and cooling. Also bought 4x stainless 250mm drive with ball bearings ( $8 NZ on a big discount on Banggood) remains to be seen how good the bearings are. Will be running twin motors through twin car ESCs.

5 years ago by jbkiwi