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>> Home > Tags > shaft diameter

shaft diameter
shaft diameter
prop shaft
propshaft
propshaft alignment
shaft diameter
Sea Queen prop shaft by sidley70 Petty Officer   Posted: 9 days ago
Hi Andy I have been working on a barn find old Sea Queen kit in very poor condition. The restoration required fitting a 5mm prop shaft as the old shaft supplied was a little short, I ordered a new 5mm shaft 19inches long from Model Boat Bits uk and when I tried to fit it it would not fit. Not realising the old shaft was 3/16inch. I had to ream the bushes to take the new shaft of 5mm. this proved a little difficult as the shaft was already fitted. I finally did it and everything works as expected. Fitting the motor which is a 700 ?. The shaft was 1/4 inch diameter. Boring out the brass insert did not leave much meat and I am hoping it does does not let go under power. So far so good. I hope there is some info there that you can use. Regards Sid

Sea Queen prop shaft by RNinMunich Fleet Admiral!   Posted: 22 days ago
I'll second that MT 👍 I'm gradually replacing all old and 'suspect' shafts with silver steel. Bought a small stock of 1m lengths of 1,2,3,4mm diameters from Conrad here. Checking with a micrometer the tolerances seem better;

Rudders and propeller by teejay Lieutenant   Posted: 24 days ago
Hi all for the second blog report on the schenllboot I am going to go over the rudder an propeller shaft assembly in more detail. The first stage was to make the rudders which were made of brass ,and having taken note of what has been said about the increase in size needed for the kit by other members I have increased the size of the rudders by 50% so that they have more effect and hopefully the boat will be more agile .I fitted 3mm treaded rod on to the rudder and in a 4mm flanged tube to reinforce the brass rod. The second stage was to make and fit 5mm flanged tube in the location for the rudders in the boat , these were made to be above the water line and will be sealed in place to reduce the possibility of leaks. These were fitted to a rudder platform inside the boat which was fitted to the kit moulding for the rubbing strip that runs the length on the boat and secured by making resin blocks which were fitted with computer extension nuts .which were then superglue in place to secure the rudder platform. The rudders were then fitted in place and held in position with the tiller collars which were made from 8mm rod and fitted the tiller arms and locked in place with 3mm computer screws and ni-lock nuts, a connecting plate was then fitted to connect the three tillers together, I also fitted rubberised washers to seal the rudder tubes. The third stage was to make the propeller supports. The centre support was a direct copy of the kit part made of brass and fitted to the kit with a plate and screws (this plate and the rudder plate were made from galvanised steel)and will sealed with resin after the I test the boat for leaks. The port and starboard supports were made by taking the kit parts and cutting them in have along the joint line or mould seam this gave me a template ,which I used to make cross-section segments but I did alter the template by increasing the boss diameter to 10mm and extending the support legs so that the finished support could be fitted through the hull (the picture of these show the mk1 version where I forgot to allow for the 4mm prop shaft which has a 6mm tube) any way the boss of these segments were drilled out with a 7mm drill and a length of 7mm brass tube fitted through the boss to assemble the segments, all of which were coated in soldering flux at this stage of the assembly which were riveted at both ends to hold it all together during soldering, after soldering the supports were then filed to the size and shape to resemble the kit parts as close as possible and fitted to the hull using a superglue and talcum power mix and then I cast resin around the extensions to secure the prop supports in place. The forth stage is the propeller shaft housing for the centre propeller housing I place a brass rod in a plastic straw and place in position in hull and using resin I sealed the hull with the rod in place this gave me a pilot hole for the centre prop shaft after I removed the brass rod. For the port and starboard shafts I used the kit parts which had hole place when assembled, this when I reinforced the housings ,the centre housing I glue 2mm of plasticard on each side and for the port and starboard I made a brass tube shroud which covered the housings which left gaps between the kit part and the brass which was filled by casting resin in the gap this increased the diameter to 10 mm so that there were little chance of breaking throw with the drill and finished these off by fill-in the outside with body filler and sanded to shape and finish . I then drilled through the pilot hole in the housings using very long extended drills and a wheel brace ( if I had use a power drill the heat would have melted the plastic of the kit and may have caused problems) I drill the shaft housings out 6mm them filed them out with 6mm file so that I could insert a length of 6mm brass tube. After all this was done I fitted a flanged bush made from 7mm tube and 2mm brass plate turned to 11mm to the ends or the propeller shaft housings. And now it is time I have to ask for some help could any one advise me on the length of propeller shafts , I know I can use a 300mm shaft for the centre shaft but port and starboard will have to be longer . and I also need advice on selecting the motors , I want to use 4mm prop shaft with 35mm propellers. Any opinions welcome.

Graupner Elke HF 408 by AllenA Fleet Admiral!   Posted: 3 months ago
Hi Dave and Doug. I love it when you two start chatting it's like tipping a cornucopia of knowledge all over the floor of my workshop. I found my original notes and the motor is a Mabuchi TD224 23. The shafts are: S.H.G Marine Miniature Propeller Shaft Assembly Stainless Steel Propeller Shaft assembly with Brass Outer Tube M2 Diameter Shafts An excellent range of miniature shaft and tube assemblies with Grade 303 Stainless Shafts and Hard Grade Brass outer Tubes. The outer tube diameter is 4mm, Shaft Diameter 2mm The Bearings are Oil / Water lubricated Acetyl material and are extremely hard wearing and quiet, The Shafts are Threaded at one end with an M2 Thread. The propellers are: RADIOACTIVE MA 3045 RC MODEL BOAT 3 BLADE 30MM PROPELLER M2 THREAD 2 OFF. As my Nimh battery is reading 8.09v so it's unlikely that there is a weak cell, I will recheck all the readings and be a little more precise to ensure I am not leading you on a wild goose chase. The biggest clue is that I have just measured the battery holder plate. The measurements are L130mm, H36mm and W65mm. Looks like the only battery that will fit is the PS-630 6V 3.0Ah 150mA 134(L) x 34(W) x 60(H)mm 0.7kg or similar. This looks right as it will probably take care of the ballast issue and it's no wonder my normal 6v battery wouldn't fit. It will be a couple of weeks before I can put her on the lake but at least the battery is ordered. Thanks again for all the info. One final thing... Can you tell me how to measure propeller pitch?

Too Powerful Brushless ? by Dave M Fleet Admiral!   Posted: 3 months ago
Hi Graham If we are talking about the Graupner Brushless Speed ​​500 ECO no 7295 https://www.graupner.de/Brushless-Speed-500-ECO/7295/ then yes the Kv is 500 which equates to 7500 at 14.8v. It's 50mm x 80mm with a 6mm shaft so really a heavy duty motor and in a Aeronaut Queen 36" still much too big and powerful. You really need to resolve the drive train and shaft problems and this will be easier if you choose a motor of smaller diameter and power. A 36xx or very similar size motor at about 1000Kv or less (500Kv with 14.7v) will be ample. The prop should be less diameter than the motor. There are many examples of 36" model boats on this site and I do believe the majority of our members have used similar set ups, to those we have suggested, in their models with a large degree of success. It could be we are talking about a different motor as you refer to " the small outrunner motor". If so please post a link to a pic of the motor.

Too Powerful Brushless ? by reilly4 Captain   Posted: 4 months ago
Graham, I have attached the same table that Doug sent me. This has the relevant information you seek. According to the table attached the Graupner 500 kV ECO has a specified output of 1440 watts and 80Amps. Strangely the 400 kV ECO has a specified output of 2010 Watts. So the 1440Watt output is questionable and may be a typo based on the other entries in the table. more likely to be 2440Watts In any case you need a 5mm diameter propeller shaft. For shaft alignment i use a brass tube that slides snugly on the propeller shaft and then on the motor shaft. When the tube rotates/slides well on both then the shafts are aligned. I then fit the motor mounts, check and tweak the alignment if necessary, remove the tube and replace with a universal coupling. If the motor or propeller shafts are a different diameter then I insert the relevant size smaller tube inside the larger of the tubes. This method is simple and has served me well, including for larger IC engine powered boats belonging to friends. Haig

Too Powerful Brushless ? by Dave M Fleet Admiral!   Posted: 4 months ago
Hi Graham Now we can see the actual prop shaft and motor it is clear that the shaft is not supported inside the hull close to the coupling. At the high revs your motor achieves I am not surprised you have had problems. I do agree with all the comments and help you have been offered and agree a 5mm shaft would help as well as a different motor. I use 3 blade brass props with brushless and have no problems but do keep the prop size to a diameter no greater than the motor diameter, as Mark advises. It's difficult to see how much space is in the hull to allow the motor coupling and shaft to be closer, but if you are replacing the shaft it may be a good time to reposition the motor and the shaft with the prop attached to a slightly different angle. This will mean opening the slot and perhaps enlarging the outside skeg but you can easily repair any damage with plastic padding to make good. Even if you keep the existing arrangement I suggest you provide support for the prop shaft close to the bearing as I suspect this is where you have experienced the problem with the vibration. A simple 2" block of wood attached to the keel and shaft would suffice. Model looks very good and I look forward to seeing some on water shots.

Too Powerful Brushless ? by jarvo Fleet Admiral!   Posted: 4 months ago
Hi Traiderman, How long is the propshaft and tube???? The reason for asking is that if the shaft is more than 6 - 8" and of small diameter, 4mm, it is likely that the shaft is whipping inside the tube, a 1000kv, ish, motor with if needed some support bearings inside the tube, what model is being fitted??? Mark

replacing propshaft by RichardSReade Sub-Lieutenant   Posted: 5 months ago
Chris, the boat is the Sea Commander, a boat my late father started in the 60's and I got to grips with it in 2015 but only floated it this year. Mark, I have just got in from the workshop and saw your comments, well guess what, after shortening the new shaft by an inch and running a 4mm die down the inner shaft and trimming it to suit, I had a brainwave, why don't I try to fit the new shaft inside the old tube which would solve the problem with the hole in the hull and keel, so I cut the old one to the required length and tapped the brass bush from the end, the inner diameter of the old tube was too small, so on the lathe with it and fed a drill down it from both ends, as I did not have a drill long enough, so the old tube is in place and the new shaft assy is fitted, all I have to do now is epoxy the whole set up. Mark have I measured the shaft angle correctly, using the keel as the flat line?

replacing propshaft by RichardSReade Sub-Lieutenant   Posted: 5 months ago
Hi all I have taken the bull by the horn and removed the 4ba prop-shaft, which was remarkably easy first using a stanley knife on the keel each side of the shaft and then as I was advised by a forum member to use mole grips, which I did, wallah out came the shaft, now as can be seen by the photos the new one, ( it is too long by an inch, Doh I ordered the wrong one) is a smaller diameter than the old one. What is the best way to refit it? Also using the keel as my straight edge, the shaft is at 9 degrees, is this going to be OK, also I am replacing the 54mm 3 blade prop for a 40mm so with the 850 motor I hope this will be sufficient.

Sea Queen Prop Shaft by AndyG009 Lieutenant   Posted: 6 months ago
Am in process of building a Sea Queen, but not with supplied motor, will be fitting a brushless. Based on the motor and the voltage it is likely to be about 400 watts output, which is about 5 times the supplied output. My concern is the supplied prop shaft which is 18" long and 4 mm dia. is there likely to be 'whip' in a shaft of that length ? Was considring a larger diameter, but that brings in the problem of obtaining propellors M4 and M5 are common. Or can one get prop shafts with centre bearings. What have other people done ? Or are my fears unfound, I remember the days when prop shafts were mild steel not stainless and bent easily.

Matching motor to Propellor by jarvo Fleet Admiral!   Posted: 7 months ago
HI Scotty, First of all, Shaft, the length is the critical bit, the roller bearing shafts are superb, so shaft Diameter, probably 4mm would suit your needs. Coupling, the center is a U/J, with inserts of the correct size, 5mm plain for the motor, 4mm threaded for the shaft. Prop. 60mm, Raboesch from Deans, 4mm thread. Contact Deans, they will sort all the right bits you need into a package. Mark

Motor problem by jarvo Fleet Admiral!   Posted: 7 months ago
Hi Richard, Good morning, Prop first, if the blade to hub is 30mm, it is a 60mm diameter prop, think of the circle of sweep, twice the size that your 550 motor can take. As the shaft is free running, we can discount drag, simply the motor working to extreme, so we need to prop down considerably, If you are staying with the 540 motor in the pics, a 35mm 3 blade prop is the maximum, a rough guide is no bigger than the motor diameter. I would save myself a lot of problems in the future and fit a larger motor, Canabus is right a watt meter will save its readings so you can get a proper idea what the motor is doing. I would swing towards the 850, or the 700. Not expensive but safe to run with a smaller prop. The 700 might fit your mounting but the 850 will need a new one, usually supplied in the box. The Sea Commander will serve you well as a great sailing model, once you are past the teething problems. Just looked back, your first post said the hull was built in the 60's, it might have a 4ba thread, not many ba props available these days, a 4mm prop will fit but it will be tight, don't forget the locking nut (to many props at the bottom of the lake) also a thrust washer to protect the motor bearings. Mark

Motor problem by reilly4 Captain   Posted: 7 months ago
Richard, If as you said each blade from shaft centreline to tip of blade is 30mm then it would not matter if you had two blades or ten. If the radius (your measurement) is 30mm then the diameter is 60mm. Perhaps you can remove the prop and place it on a flat surface so you can see the swept circumference when rotated.

Motor problem by reilly4 Captain   Posted: 7 months ago
Hi Richard, If each blade is 30mm from the shaft centre, it is a 60mm diameter propeller and is far too big for that size motor. For performance you need a larger motor say a Graupner 700 and I would still recommend a smaller propeller.