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>> Home > Tags > racing prop

racing prop
brass prop
prop shaft
prop tube
propshaft alignment
racing boat
racing prop
Motor problem by jarvo Fleet Admiral!   Posted: 3 months ago
Hi Richard, looking at the markings on the motor case, it might be a 550 type, and rated at 7.2 volts, so it would seem to be at the top end of its capacity, did you manage to get the prop diameter? also is it plastic or brass? A 600 motor is a bit larger size and power wise but would still fit your motor mount, they are common in power drills so usually have plenty of torque, but can be power hungry. A prop to suit would be about 40mm, 2 blade or 35mm 3 blade both in brass, plastic props tend to be racing types with deep cuffs on the blades, possibly the cause of the burnout! The 850 is a lot larger and more powerful but would need a new mount and again is power hungry, probably needing 12 volts as well. Have a look on ebay 600 motors are about £5, but check to see what the rating of your ESC is, needs to be at least 20amps, although if it survived cooking the old motor it must have a good rating. Add a 15 - 20 amp fuse for protection. Just had a thought, is the prop shaft stiff to turn? should spin freely without the motor connected, might have old oil or grease in the tube causing excessive drag, this could cook the motor as well. A pic of the prop and its size would be a great help. Hope this helps Mark

Jaydee by Dave M Fleet Admiral!   Posted: 4 months ago
Hi Ian It's a racing prop and will use lots of power hence the heat. As you have a cabin cruiser it does not need such a coarse pitch prop and changing to a prop with a lesser pitch will improve your running time and produce less heat. Performance will depend on the chosen prop but should not be much different from what you already experience. As you already have a water cooler inlet and outlet you could just wrap some copper tube round the motor and connect with silicon tubing to keep the heat down Dave

Red Cat hydroplane by RNinMunich Fleet Admiral!   Posted: 4 months ago
Hi, Ta for the info👍 Glad the burn-out problem is solved. Would like very much to know what make and model your BLs from HK were as I have just bought a couple from them 😲🤔 Mind you I'm not going racing so mine are only tiddlers like the Propdrive v2 28-30 1000kV. Cheers Doug 😎

Crash Tender Shaft Tube Poistion by Dave M Fleet Admiral!   Posted: 5 months ago
Hi Neil That link for the seal is for a flexishaft drive. Totally different to a propshaft and proptube. Used by the fast racing fraternity. I am not sure it would work in your setup. Anyone used one with a solid propshaft? Dave

Overlander Typhoon 625 by Dave M Fleet Admiral!   Posted: 5 months ago
Used to be fitted to the Chinese imported fast gentleman's run arounds. Fast torky motor and I suspect a suitable alternative would be JP Pro Power 480 Electric Flight Motor Match it with one of Simons (ex Prop shop) racing props and you won't be disappointed. Dave

propshafts by Dave M Fleet Admiral!   Posted: 5 months ago
Hi Doug I agree a 600 is probably too heavy. Looking on Cornwall Model Boats site the motors sold for the kit (currently unavailable) look more like 400 size. I have used JP Power 480 motors in small craft and they are very punchy, light 92g and will work very well on 7.2v with a shaft diam 2.3mm. I agree the Raboesch prop shafts are good but to keep the weight down I would be looking at 3 or 4mm. Prop Shop have three bladed racing props specifically for this motor. Dave

Bademenuss by Krampus Captain   Posted: 7 months ago
Altered Krick Lisa M model kit seeking realism. Inspired on 1970s 40, 42 and 43 Hatteras, Uniflite and Viking Double Cabin American yachts. 9v LED navigation lights system. Approx. 1/20 scale. Real life boat could be nearly 39 x 13.7 feet. Similar real-life Hatteras 40 Double Cabin yacht measured 41 x 13.7 feet. Runs with NiMH 9.4v battery, an HPI Racing 1145 Gt 550 Motor 14.4V, and a 40mm 3 blade propeller.😁

Fairy Huntsman by Dave M Fleet Admiral!   Posted: 7 months ago
As this is a refurbishment chances are it was fitted with an IC engine in which case you need to remove all the gunge and heavy mounting blocks from inside the hull as well as checking the propshaft and bearings. If you can get the weight reduced then I would expect a speed 600 motor with a 30 to 40 mm prop should suffice. A 20/25 watt ESC powered by a NiMh would also be suitable and keep the weight down. If you use racing props the current will be greater than if you use brass 3 blade props, and the bigger the prop the greater the current. As a general rule the prop should have a diameter of no greater than that of the motor. The voltage of the NiMh must not exceed the max voltage the ESC can handle. A higher voltage will reduce the current draw so a 9.6v may be better than a 7.2v and give a longer run time. If you already have batteries for other models I would use those but SLA's are heavy and may hinder planing. If you already use LiPos then make sure your ESC can stand the voltage and has a built in cut off to protect the battery.

Battery problems by pmdevlin Fleet Admiral!   Posted: 9 months ago
My knowledge of "elecy" stuff is pretty limited, but I see that the model boat world (excluding racing types) is in the dark ages compared to planes, helis, cars etc when it comes to motors, batteries etc We have to reply a lot on testing, fiddling etc when it comes to gettingn a fast electric set up, in a scale heavy old wood boat😁 as there isnt much info out there. I tried testing over a long time, with one boat inparticular, and was lucky enough to have te use of eagle tree data logging, so could measure watts, amps, gps speed, voltage drop and so on, and analyse the resultsd on graphs etc back home on the pc. Its amazing to see that sometime s the fastest set up isnt always the best when you compare run time, amp draw, heat, voltage draw etc, and what "looks fast" sometimes isnt as fast as you thought😊 This boat for example, 6kg, ply construction will do 25mph, after that torque roll is kicking in, and it want to roll over. I tested props over a long time, using cheap plastic "X" props, and with the results was then able to get a more efficient and visually pleasing brass cleaver 3 blade one. Ranging from 50mm to 55mm the amp draw went from 45a to 90a using same batteries!, and teh highest amp draw prop didnt produce the fastest speed, all interesting stuff. The boat is similar to the OP perkassa. I also went from direct drive, to a geared drive, and can change the characteristics of the boat using different cheap gears, eg., small lake, dont need top speed, so change to acceleration, big lake, lets give up acceleration and have top speed, and so on👍

Battery problems by pmdevlin Fleet Admiral!   Posted: 9 months ago
something is fundamentally wrong here, there is no way that motor/esc/battery combo should have fried the esc in your perkassa. I have a number of large scale boats with a fast brushless set up, I pull almost 90 amps with one of them, on the initial acceleration, using 6 cells, 120a esc and (here is the difference) a 900kv brushless motor. The racing guys use high kv motors, they need the high revs, with a heavier boat like yours, you need the revs, but also the torque, which is a lower kv motor Before you do anything else, buy something like this really cheap, but saves you a fortune. As many of previous posts have said, you need to measure what is going on, for example, the specs of you motor say max current is 100amps, you need to measure your amp draw. You know the esc was 160a with a burst of 200a, so should have been well within the capabilities of your set up, but we cant see the prop. If its too big, and too coarse, particularly holding the boat, the amp burst would have had to exceed 160a to pop the esc, which is also well over the motor specs. I doubt the hobby shop will do anything, as the fault could have been a multitude of things, Personally, I think that motor is way too high KV, and I'm saying this from experience of large, heavy scale boats, with fast brushless set ups. I would have expected it to rev very high, but not deliver a really fast top speed, but I could be wrong. Shame really as its quite an expensive set up there. Are you sure about the facts, holding that boat, and max throttle must have been pulling your arm off, I cant hold any of mine😱

Battery problems by Dave M Fleet Admiral!   Posted: 9 months ago
Hi Allan The motor and ESC seem well matched which points to the prop being too coarse a pitch. You have a large scale boat not a fast racing boat and I suggest you replace the prop with a brass three blade of 35-40mm. As we have suggested a wattmeter will help you determine which is the most suitable for your set up. My Sea Queen with a similar set up (40mm brass prop) draws 30 amp at full speed so well within your ESC and motor spec. I see you have water cooling and am wondering if this is working correctly. You should see a good flow of water from the exit port at all but the lowest speeds. The inlet scoop should be immediately behind and facing the prop with a good straight pipe run to the ESC and motor cooling points. Dave

Battery problems by Dave M Fleet Admiral!   Posted: 9 months ago
Hi Patto I agree with what has already been posted, but it would help if we knew the size and type of prop you are running with your brushless motor. Fast large racing props do not work well with brushless unless your battery can provide the very heavy sustained current required. As Haverlock suggests a Wattmeter will allow you to select the best prop for your set up. LiPo power will give you all the speed you need but at an initial high cost as they require special chargers and correct management. You could use NiMh batteries which are lighter than SLA and are more suited to high discharge currents. You can get these in 12v packs and 5000mAhr would be a good starting point. If your motor is cutting out it is more likely the ESC is the culprit due to too high current draw. Another possibility is that the propshaft is too tight, it should turn freely with no tight spots and have thrust washers at both ends. Dave

Bluebird K7 by Dave M Fleet Admiral!   Posted: 11 months ago
Hi midlife306 Welcome to the site. Impressive looking model and its will look spectacular once painted. Is it mainly wood construction? If so are you intending to cover the wood inside and out to protect against water? If you are intending to use IC engines you need to find some where to sail as most waters prohibit their use mainly due to the noise and pollution. The hull is a fast racing hull that would suit a brushless set up with LiPos. There are many configurations and I suspect a surface piercing prop is one option. I suggest you find a local model boat club near to you and go and see if they run fast race boats. There is a section on this site for Model Boat Clubs that will help you find one locally.Hopefully they will be able to guide you into the best set up for this hull. I have a fellow club member who is really into speed and he sources his bits from Prestwich Model Centre but also from the States. Please keep us posted on progress and do keep asking for help and advice, it may just save you from making costly mistakes. Dave

Battery Life by Dave M Fleet Admiral!   Posted: 1 year ago
Keith I have just seen your post re the Phoenix. If this is the model then I suspect the prop is perhaps too large for the brushless motor which will be struggling to reach max revs. Net result will be high current and short run times. If you can get or borrow a watt meter this will tell you the current draw and watts whilst holding and running the boat in water. Trying different size props will identify the best match. Personally I dont use s type 2 blade racing props on my models with brushless as they tend to be too coarse pitch. A good 3 blade brass prop will give realistic speed and long running times. My Sea Queen has a similar motor to yours and gives me about 45 mins if I run at full throttle. Pic attached of the model and setup. I also have a 34" Crash tender with a similar setup so some pics attached Dave

Brushless by Dave M Fleet Admiral!   Posted: 1 year ago
Hi Brian I am not sure which model you are referring to but your description of period photos suggests it is from the late 1930's and yes they were not a planing hull. Does your model have one or two props? A few pics of the model would help, you can upload by clicking the yellow box to the left of this input panel. Brushless can be a bit daunting at first experience but they are not difficult to use once you are familiar. You will already have seen they have three input wires and these need to be connected to an individual Brushless ESC for each motor. Doesn't matter which wired connect to which socket on the ESC but if your prop spins the wrong way you can swop any two connections to change the directiopn. The kv rating refers to the unloaded speed of the motor for every volt you apply so for say a 1000kv motor supplied with 11.1volts the motor would spin at 11100 revs. There are two types of brushless motor "in-runners" and "out-runners". This refers to the construction used with in-runners generally being less bulky. The outrunners will produce more tork and can be more suited to slower speeds. If you need to water cool the in-runners have a jacket fitted around the motor body whilst the out-runners use a water cooled mounting attached to the bearing. Both are suitable but I personally prefer Out-runners. For your model I suspect an inrunner may be preferable due to the restricted space available. Unlike brushed motors brushless do not like being overloaded and work best when they can achieve their max efficiency at near max revs. They have a max watt rating which should not be exceeded (Watts = Amps x Volts). The casing may be marked with numbers 42-56 which is the diameter 42mm and length 56mm. In my 48" Sea Queen I use a 42 size 850Kv water cooled motor of 700 watts and it is happy driving a Prop Shop prop of 42mm at 45 amp on full throttle. To measure your wattage you need to acquire a Wattmeter to measure the actual current draw with the model in the water. This will give an indication of the max current at max load as you hold the model stationery. If the watts are greater than the motor's rating you need to reduce the prop size/pitch. I like scale props so use 3 bladed brass and avoid using racing plastic/nylon props as they can overload the motor. The ESC should also be of a sufficient rating to handle the running current, I usually try for at least a 50% margin ie 75amps for a 50amp max current. Finally your setup must be really secure (I know from personal experience) and free running. The revs produced are possibly higher than what you may have experience before and any fault can and will escalate very quickly. At high currents the motor coils will fry in about 2 seconds should anything stall the motor and you can expect to see smoke and a ruined motor. If you post some pics we can give you more detailed help on your particular setup. Dave