Response

Test fit the Rudder!

Hi Ed I notice that your prop shaft sticks out from the hull which may be why the prop is so near the rudder. I treat all plans as guidance notes and trial fit the parts before final fixing. I believe we have all been in your position at some time or another! I agree with the advice already given and believe a thin washer and thinned would give you the clearance you need. This isn't a speed boat so there will not be much stress on the set up but my preference would be brass, its easy to file and won't rust. I have in the past reworked the propeller boss but its not really a good idea, and does tend to spoil the looks.

6 years ago by Dave M

Response

Test fit the Rudder!

Evenin' Ed, No! you need some kind of thrust washer between the prop / and the end of the tube! Otherwise when full ahead the prop or nut will grind against the tube 😡 I would swap the thick nylon washer for a thin stainless steel washer. A good DIY store should have some. Should win you a mm or so. if the shaft moves back and forth more than that then something else is wrong. The movement on my Sea Scout shaft is about 20 thou max. Or as RH suggests you could use Loctite to secure the prop instead of the . I would prefer the stainless washer. Cheers Doug 😎 BTW: I also fit washers at the inboard end, between a collet and the tube. As shown in pic attached of my new Sea Scout installation. New propshaft was milled to lock the collet in place (Pic 2). Cocked it up slightly so I needed extra spacing washers! 😁 no one's perfect 😉

6 years ago by RNinMunich

Response

Test fit the Rudder!

Funnily enough, was talking about this issue earlier with other scale modelers. I faithfully reproduce the rudder position and size and then propeller shaft protrusion on my scale models. Often find when the shaft and propeller are installed they either contact or come very close to the rudder leading edge. Suspect model propellers and the boss are thicker than a scale propellers. Have resorted to trimming either the rudder or the prop boss to get them in properly. Also, have several times left the prop. off and Loctited the prop to the shaft. Be interested in other's experiences. Have never lost a prop by using Loctite fortunately.

6 years ago by Rowen

Forum

Too Powerful Brushless ?

I have to agree with Peter's comments. I would also suggest that you look at the coupling and fitment of your prop shaft. it could be that the whole unit is seizing together. You also need to check it is true and free running. You need a prop and followed by a thrust washer then at the inboard end a thrust washer and coupling. There should be a gap between the thrust washer and bearing of a few thou', we used to use a Rizla paper, Make sure all joint are tight and that the shaft turns freely and smoothly. The motor need to be securely mounted to a good solid base and 100% aligned with the coupling and prop shaft. Personal experience tells me you don't get a second chance with brushless, you have been fortunate if it is only the prop tube has suffered. Is your hull wood, plastic, fibreglass? Whilst Araldite is a fine adhesive you may need to use Stabliz Express or UHU Acrylit Plus which provide an exceptionally strong joint. E-bay have sellers of UHU in the UK. Good luck and please keep us posted

6 years ago by Dave M

Forum

Motor problem

do a test run in the bathtub you can leave the superstructure off and use the throttle while holding the boat in place make sure you wife is out so the bathroom has time to dry out afterwards. Give it a run and see how hot the motor gets. The 850 is specified such that your prop should be fine. Please remember to include a otherwise if you select reverse your prop could unscrew while sailing and you may lose the prop. Let us all know how you get along and enjoy .

7 years ago by Haverlock

Forum

Blown esc........ again 😢

What ESC were you using? My experience with 600 motors is that they are power hungry, smell a lot and get very, very hot. I had two in a Slipway Trent (they advise the ECO version, no longer available) and used to be able to smell them from the shore! Could be the ESC internals circuitry shut down and may start working again when cool. Any weed in your pond will definitely overload them, which was my problem. Too big a prop will also cause overheating. I had 40mm 3 blade brass props in the Trent. It's possible that the motor is to blame if it has cooked the coils and caused an internal short. Try running direct from the battery with an ammeter in circuit. I am assuming you have checked your propshaft for free rotation and no binding, s can and do come adrift and can tighten up on the shaft, which may explain the slowing down you experienced. Please keep us posted with your progress Cheers Dave

7 years ago by Dave M

Response

propellers specilly made

Hi cliff How are you going to attach the props to the shaft? Normally if the prop shaft has a plain and threaded end, the threaded end goes to the prop with a and thrust washer, The other end inside the boat has a thrust washer and a collett with grub screw(s). Dave

7 years ago by Dave M

Forum

Richards 48'' Swordsman

Hi Richard Whilst the delamination appears local chance are the fuel has penetrated well into the laminates together with water. Use whatever you want to patch the damage but a fresh piece of ply will probably be cheaper and more resilient. Cascamite will not work well with cyano. I would, after sorting the damage, use a thin resin poured and swilled around the hull insides to seal, followed by a covering of glass fibre or cloth over the outside impregnated with polyester lay up resin. You can fill any resulting blemishes with car body filler. As the model had an ic engine chances are the prop shaft will be showing signs of its age. Even if the bearings appear ok'ish the shaft is most likely bent or twisted. I suggest whilst you are sorting out the delamination you purchase a new unit of the same size. Most modern kit is metric so your shaft should fit any props and couplings you purchase. Some use an allen key to secure the coupling so this may not apply. Don't forget to fix a and thrust washer at either end of the prop tube. If you look at the blogs on this site there are several example of how others have completed similar tasks Hope this helps Please keep asking if you need any further help Dave

7 years ago by Dave M

Forum

Skeg on King Fisher

Hi Grandpa Looking at the latest photos suggests the shaft and keel will be secure and if the prop is clearing the hull then the shaft may be long enough. You may need to add an extended coupling to allow for the motor. As I mentioned it would be a good idea to fit the motor, coupling shaft and prop now to make sure it all fits nice and square and runs freely. Don't forget you must have thrust washers at either end of the propshaft together with a for both the coupling and prop.😁 I am in the Crewe club and Mark I believe sails with Etherow. We are both North West clubs so a few hundred miles from Canterbury. Good to hear you have a local modellers Club. Good building Dave

7 years ago by Dave M

Forum

Propeller 101

Thanks for advice Haverlock. Had picked up on the left-hand / right-hand thing but the tip about a is very useful. Probably saves on a bit of wading as well as preventing a lost prop!

8 years ago by ThatSinkingFeeling

Forum

Propeller 101

Do not forget to specify right or left handed the thread is the same but the direction of rotation is different and please do remember to fit a ( and use locktite) so your new prop doesn't join the rest of the lost bits on the bottom of the pond

8 years ago by Haverlock

Forum

Scudder

I would agree with Haverlock's advice so far and would add the BRChobbies is a good supplier of motors/Esc and batteries. I have used them in the past and their products are 1st class. I also believe you will need a much beefier motor and ESC (your wattmeter) will give you the amps and watts used so you will be able to avoid cooking and electrics. NiMh batteries give good power but for your application you need lots of power and LiPos are the best choice. Going back to my flying days it was usual the try several different sizes and pitches of propeller before the optimum was achieved. You cannot just add any prop to a brushless motor as they require a load that enables them to work within their wattage. That is why you need a Wattmeter so you can check and also make sure you are not exceeding the ESC rating or overloading the battery capacity. This is important with LiPos as they should not be discharged below about 3.3v but this should be marked on the batteries. Many ESCs have a built in cut off that can be set to the correct value. Unlike other batteries LiPos change internally if abused and there have been many instances where fires have resulted. U-tube has many examples. If you are new to LiPos then you need to be aware of the correct charging procedure using a dedicated charger. LiPos should never be charged unattended and preferably in a charging bag in an area near to an outside door should the need arise. I have used LiPos for many years without incident so correct use will reduce the chance of any accidents. As with any high speed high power setup you do need to make sure everything is securely fastened and the wiring neat and of the correct capacity. I once cooked a motor because I had not secured it correctly, I now always use bolts s and washers, and check the mounting before every sail. Good luck and some pics and perhaps video on water would be good to see Dave

8 years ago by Dave M

Forum

Brass propellers

I have in the past threaded some brass bar and sweated this onto the prop shaft. Using a lathe you can then turn to the new die size and make a new thread. Make sure there is room for a to fasten the prop. If the shaft bearings are thick enough you could buy an M5 threaded shaft and make new bearings or ream out the existing bearings. Dave

8 years ago by Dave M

Forum

Left Hand props and shafts

HI Les Haverlock has already answered your question relating to the thread and I agree particularly with his advice to use a . The use of the correct thread is very important if you are running a very fast and powerful racing type of model where the forces acting on the prop are not small and are best used to keep the prop on the shaft, even with a . The use of a on a scale model where both forwards and reverse may be used frequently should help keep the prop in place. As regards two props it is beneficial to use contra rotating props as the model will be more balanced under way and will also respond correctly to the rudder in both directions, as already advised by jgs43. If you are modelling a true scale model of an original, say a lifeboat, then it will be important to replicate the full size arrangement on your model.

9 years ago by Dave M

Forum

Left Hand props and shafts

Most props whether left or right handed come with a right handed thread. The one company which does provide props with right and left hand threads is Graupner but only on some of the types and sizes - the thread direction is coupled to the handing of the prop so that they tighten on the shaft when running forwards. Does mean that you need to source a left handed thread on the prop shaft and I have only found one german shop/manufacturer which is able to supply M4 Left hand threaded shafts. As said by other posters easier to stick with right hand threaded and use a . The props should rotate in opposite directions and the direction of rotation does create different effects on full size boats - e.g. raising or lowering the bow when running. Outwards turning props (top of prop) are also supposed to improve manoeuvering and are generally used on tugs and the like. There is also supposed to be an effect on achievable speed but you would need to search for the relevant article on the web. When the prop turns the boat tends to try and rotate in the opposite direction due to torque. Having the props on twin prop boats rotate in different directions cancels out this effect. The pilot on single prop boats is normally positioned either right or left to help counteract this effect - there are some very interesting articles to be found on the web referencing these subjects with respect to full size boats

9 years ago by jgs43

Forum

Left Hand props and shafts

If the prop had a LHT the shaft would also need to be LHT. in practice use a !!! its no different having the left handed prop running a boat forwards than a right handed prop running a boat backwards.

9 years ago by Haverlock

Forum

Four Motors Wiring Advice

Use a !!!! And if they still come off in the test tank ( or as my better half insists bathtub) try some blue thread lock.

9 years ago by Haverlock

Forum

CLUB 500 BOATS SHAFTS SEIZING

Thanks pmdevlin for your reply, On 2 of the boats I altered the u/j at the motor end to lock on with a grub screw and the motors are all held in with double sided tape bands so they are very rigid. They were all fitted out internally prior to the deck being fitted. The shafts all had endfloat. Even when the prop and and u/j were removed we still could not shift the shaft until we gave a short sharp blow to the end it. The shaft was a dull silvery colour where they rotated in the bearing.

9 years ago by HoweGY177

Forum

Motor Size for Vliestroom, Model Slipway Buoy Vssel

From the info you have provided it would appear one motor /prop shaft is running tight. Turning the prop of each motor should feel free. if one is tight then it's likely your lock nuts at each end of the propshaft have become loose and tightend on the prop tube. Releasing the coupling and slackening the prop shaft should solve the tightness, if it's still stiff then you possibly have a problem with rust etc in that shaft, which will need to be removed and cleaned with wire wool. Do make sure the at the prop end is tight to the prop, the adjustment is made at the coupling end, and there should be a washer between each and the prop tube. Play should be minimal, we used to use cigarette papers but as long as its free all will be OK. Too big a gap will allow water seepage. You can check the motors by disconnecting the ESC and applying the battery direct. Both motors should give similar performance. Haverlock has explained how you can check each ESC but please do heed his advice about disconnecting one of the red wires from the receiver plug. Each ESC has a built in BEC circuit and you will experience some strange results if two are connected to the same receiver. As a matter of course I usually test all me new ESCs with a small motor outside the model to make sure it is working OK. it was not unknown in the past for ESCs to fail out of the box. it doesn't happen often and I have always received a free replacement but it's easier to find out before installing. if you do have a damaged motor perhaps you could provide a picture so we can advise as to a suitable replacement. A 50p coin included in the pic will help gauge the size.

9 years ago by Dave M

Forum

Blowing fuses

HI Georgio I have an Aerokits Solent (pics attached). Some pics show the model in an earler guise. I have recently upgraded the electrics and corrected the number. its a model of the Douglas Currie 48-016 This type of lifeboat had a top speed of about 9/10 knots so was not as fast as the later fast afloat boats. Two 850 motors would be much to powerful for this model. Regarding the waterline most models I see are usually ballasted far to low in the water, the real boat had a draught of 4'8" and in service it was usually possible to see the white bottom paint just above the waterline. I use two Bhuler 12v motors with two electronize ESCs and a 12v 12 amp SLA. Sails at scale speed and I can usually get a good hour if I use fast speed sparingly. The fact that you have lost a prop suggests that you may not have thrust washers and s at either end of your prop tubes. As you have found without a the props can and do become detached. Another symptom is that without lock nuts the whole shaft can tighten up and seize, especially if you do not have a at the drive end. The thrust washers take the load when going ahead or astern and you should adjust so that there is minimal play between the washer and bearing. We used to use cigarret paper to set the clearance. Glad to hear you are managing to sail, I used to sail on the original lake when I lived on the Wirral, and I do hope you can sort out all the niggling little problems. Cheers Dave

9 years ago by Dave M

Forum

How do I fit a propellor shaft ?

HI George I am attaching an exploded view of a prop shaft with the prop, and washer plus the bearing which will fit in my prop tube. This is for demo purpose only as the nut and washer are not brass, but hopefully it gives you how it all fits together. Cheers dave

9 years ago by Dave M

Forum

Precedent Huntsman 461/2 Inch

HI Glyn This might be a bit late but add a drop of thread lock to the prop, also make sure the is tight. If the weather was as bad down your end you may not have sailed the boat. Dont forget post some pics Mark

9 years ago by jarvo

Forum

Motors overheating

HI Mark, Think I found one motor which is a bit faulty (doesn't turn as freely as the other) and possibly a very slight bend in the shaft. I'm also using raboesch couplers from motor to shaft so they seem to be fine regardless of the angle. They aren't perfectly aligned but as close as I can get considering the hull design and motor size. I'll try a new shaft and a new motor and see how it handles. As for s - everything is tight so there is no movement at all. No thrust washers in place on either side. Would that make a huge difference? Thanks again for your help! Thom

10 years ago by Thom

Forum

Motors overheating

HI Thom I was thinking you had something like 60mm props, with small props there is something wrong with the driveline. Are the motors and shafts in line both vertically and horizontally? If you remove the couplings the shafts should be very free to spin if not remove the shaft from the tube and role it across a piece of glass, (the glass is very smooth) there should be no wobble or twitching anywhere along the shaft, if there is the shaft is bent and will need replacing. The amp test will show which one is the worst and go from there. Just had a brainwave!!!! (don't happen very often these days.) The s on the props and couplings, is there a little end float, IE. the shaft can move back and forth slightly, possible the shaft is locking up. Also are the thrust washers in place on both ends???? Mark

10 years ago by jarvo

Forum

fireboat cof g

Reading this thread it occured to me that you may have a bearing problem. Your last post seems to suggest that you do have some concerns. Was this model originally powered by an IC engine? My 34" certainly had been and the shaft and bearings were to put it mildly - worn. I took out both and refitted with new to the same size - bit of a pain I know but well worth the effort. I use s at both ends of the shaft and make sure I have thrust washers at each shaft end. Hope this helps. Dave

15 years ago by Dave M