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>> Home > Tags > prop tube

prop tube
brass tube
brass prop
prop shaft
propshaft alignment
racing prop
prop tube
Twin screw by RNinMunich Fleet Admiral!   Posted: 12 days ago
Hi George, Had this snag with my Graupner Graf Spee as well. In my case the stbd prop tube was misaligned 😲 Major surgery 😡 First off; it's unlikely that the motors are perfectly matched, but if the difference is that noticeable I would suspect the cause lies in propshaft resistance and / or dry motor bearings! I would disconnect the prop shafts, oil the motor bearings and run them in a bit off load for a few a minutes. See if you notice a difference there at low speeds. Also; remove both shafts; clean and oil. Clean the tube end bearings with a pipe cleaner and some light machine oil. Squirt some Teflon grease into the tube from the prop end. I use a small plastic syringe for that. Before reassembly check as far as possible that neither shaft or tube is bent at all🤔 If all seems straight reassemble and run the motors at medium speed a minute or two then slowly and see if you can still detect a difference. Reduce the throttle gradually until the motors stop. If one stops significantly before the other that suggests extra friction in that drive train; misalignment somewhere! Thrust washers too tight? BTW: which motors? One ESC or two? Hope this helps! Cheers, Doug 😎

ELCO 80ft PT boat Jumping the gun by CB90 Admiral   Posted: 12 days ago
Yes, jumped the gun and brought the motors. Already have 3 light weight Aluminium prop-shafts that I intend to use: Tube Length:25CM/9.84inch Tube diameter:8.5mm/0.33inch Shaft diameter:4mm/0.15inch Stainless steel Weight:67 g The Motors will run on 3s -11.1v Three of these (one as spare): High Performance 2808 1400KV 14 Poles Brushless Motor Max Watt: 350W Voltage range: 7-15V Max amps: 35A No load: 1.2A One of these as centre motor or my swap for spare of above: High Performance 2826 900KV 14 Poles Brushless Motor KV(RPM/Volt): 900KV Max Watt: 1000W Voltage range: 7-18V Max amps: 60A no load : 2.2A

Spektrum, new, useless... by Haverlock Fleet Admiral!   Posted: 30 days ago
in runners get used in the model car crowd other than that they are used in FAST boats. As with most things its a trade off in runners lower torque but more revs ( for any given wattage ) match the prop to the motor and your going faster with an in runner. one example!

Hull Pt2: Motorisation - Come What May!! by RNinMunich Fleet Admiral!   Posted: 1 month ago
As promised (or threatened?😁) stage two of the hull work and thoughts on motorisation. The hull was sprayed with two coats of grey primer/filler. Pic1. As usual this showed up the remaining imperfections (pics 2 & 3), but I'm not going to worry about them until I've got prop shaft tube and rudder stock sorted out and permanently fitted 😉 After my attempts to make and thread a 3mm prop shaft went awry Martin (Westway the Mechanicals Master👍) stepped in and made me a decent one complete with a bushed stuffing tube 👍 Vielen Dank Meister😊 I did however manage to make a 4mm to 3mm reducer so that I could fit a Rabeosch 35mm prop as seen in pics 2 & 3. The tube and shaft from Martin, arrived Saturday an' he only made it on Monday😊, have been dry fitted so that I can start setting up the gears, necessary to bring the drive down to the prop shaft fitted very low down in the hull, and motor mount. Pic 4. Motorisation: (Remember folks - this kit was designed and built as a static model!) I want to use the old 1950s Taycol Target motor which my Dad originally fitted in the Sea Scout which I have renovated and upgraded to brushless. See Build blog 'Sea Scout - Jessica' Many of you will know that the Taycol motors were field coil motors, meaning that they have no permanent magnet around the rotor coil, and thus reversing the battery connections to the brushes had no effect on the direction of rotation, as this simply reversed the magnetic fields of both stator and rotor coils🤔 To counteract this so that the motor could be used in both forward and reverse with a conventional brushed ESC I modified the motor slightly (separated the two coils) and built a simple converter board to connect it to the ESC. Again see the Sea Scout blog for the details of the conversion. Basically; once the field coil and brush-gear (rotor coil) have been separated a simple diode bridge can be used to apply the output of the ESC to the motor. This enables the reversal of EITHER field OR rotor coil polarity, depending on how you connect the converter to the motor. Thus reversing the direction of rotation of the motor. Beneficial side effect is that the diodes also suppress the commutator sparking😊 In my case, with the Taycol Target, I also cleaned, flattened and polished the commutator. Thus significantly reducing the potential for spark generation in the first place! A peculiarity of the Taycol motors is that they all use metal brushes, pressed phosphor bronze strip, so they need oiling! DO NOT oil conventional brushed motors with carbon brushes unless the brushes are exchangeable or you want to have to buy a new motor!!!!! Pics 5 & 6 show the proposed position of the Taycol in Gina 2 and pic 7 the prototype converter board I knocked up to test the motor, together with a Graupner Navy V30R Marine Brushed ESC. Details and results in the Sea Scout blog, including video of the sparks and oscilloscope pics of the drive waveforms before and after conversion! The latter showing the spark suppression effect of the converter😊 Some samples attached - last 3 pics. Pic 8 pic shows a more compact version of the converter, one of a few types I'm doing for Martin's various Taycols as a trade for the prop shaft he made for me and some useful material he sent. Thanks mate👍 Next steps will be 1) mounting the gears correctly on the shafts, requiring the manufacture of a 3/32" to 4mm adaptor and a 1/8" to 4mm adaptor, and keying them to the shafts - Hooray for mini milling machines 😉 2) manufacturing bushed end plates to hold the gears in place, 3) fitting the motor mounting platform. I'll probably borrow from my experiences of real shipbuilding and do this as a suspended 'false floor', i.e. mounted on stiff springs to enable adjustments to optimise the gearing mesh! On real naval ships this is done to improve shock resistance and to minimise engine noise / vibration conduction to the hull, thus significantly reducing the acoustic signature of the ship. Not that I'm tooo worried about being torpedoed 😁 Worth a try😉 Pic 9 shows the cleaned up and renovated Taycol Target motor. Pic 10 shows the drive waveform complete with sparks before modification.🤔 Pic 11 the cleaned 'forward' waveform with the converter board. Pic 12 the cleaned 'reverse' waveform, no suppression capacitors needed 😉 More soon folks, Cheers, Doug 😎 PS Along the way a new keel was fitted as can be seen in pics 1 to 3. The original builder had 'buried' the keel in the hull planking! 😲

54 year old Crash Tender by RNinMunich Fleet Admiral!   Posted: 2 months ago
Thanks Martin, I'll keep that in mind. Be a while til I get to above deck fitting though. Ain't got no deck yet 😲 So, prop shaft made, tube glued in, prop screwed on the shaft. Now to glue in the rudder stock, 3mm I/D and glue and pin the new keel I made last night. Then maybe I can prime / paint tomorrow!? 'Die Hoffnung stirbt zuletzt'! 'Hope dies last' 😉 Cheers, Doug 😎

54 year old Crash Tender by Westquay Fleet Admiral!   Posted: 2 months ago
Ah, old car days, eh? Nothing phased us. Can't touch them now. No idea what it all is under that plastic cover. Spookilly, I've just done a pattern in 1/32nd scale for a Maranello GTO1964. One of my favourite cars messed over by Maranello for Le Mans. Your fish cutter seems to be throwing some problems up, but nuttn' a spot of resin can't fix. I don't buy that propellor blade rumour. We have no decent pics of the thing, but you can clearly enough see there aint no twist in the legs like a prop would have. I've just made mine in brass and simply flattened the tube in the vice to get a similar section and soldered to other tubes. All I have to do is make rings and attach the blocks for the ensign ropes. Also cut and attached the toe strips either side of the decks in Venetian blind slat, some leftovers from decking the Vanity cutter model. Now I need to cut some mahogany and attach to the side of the decks as the rubbing strake. Finaly will be making gutters for the smaller windows (NO frames there) and frames for the wheelhouse windows, then I can paint it. I have decided on white roofs after a peer at the good photos again, where the vents all seem to be white. But non-slip was clearly a pain to clean as the roofs and decks are bloody filthy! Vincent's having a break for a while. Call it my annual leave, which I never normally have. Cheers, Martin

Charging NiMhs, one for Doug?... by RNinMunich Fleet Admiral!   Posted: 2 months ago
Hi H, have you actually seen the TX battery? It has contacts deeply recessed in the case, the corresponding spring contacts are in the TX case. There ain't nowt to clip onto 🤔 Only way would be to make a little jig and frame to hold some spring contacts. Then cables to 4mm bullets. Is it worth the bother? Cheers Doug 😎 PS decided not to saw into the already fragile cutter hull. Am about to EzeKote the outside. Will pin and glue a keel extension on later, prior to fitting prop tube and rudder stock. 😉

Wheels by RNinMunich Fleet Admiral!   Posted: 2 months ago
Great job, and nice clear pic 👍 Thanks Hammer 😊 Now we can see the refinements of your construction. Good stuff. I also use a mini gas torch sometimes, in pistol grip form with adjustable flame. Pizo ignition, dead easy. Get 'em in good cooking accessory shops. Good for soldering oil tubes on brass prop tubes an such. Cooks call them Gourmet Torches and use 'em for their Crème Brulet 😊 Also various electric irons, 50 W with a 1/4" chisel bit for big stuff, standard 25W general purpose, temp controlled 25W,and a mini 1mm bit temp controlled for SMD work. Good for small LEDs etc. Cheers, Doug 😎 PS Also one electric iron 1200W ........ . . . . for ironing shirts! Ugh!! 😡

Spektrum, new, useless... by RNinMunich Fleet Admiral!   Posted: 2 months ago
I agree Haverlock, One definitely, potentially, possible final thought😁 Martin; Did you pull the bind plug out BEFORE you switched off the RX? If the green light at the RH end of the LEDs on the TX was lit it MIGHT mean the RX was bound OK. Can happen so quick you may not have noticed! Esp. if the better half popped her head round the door to offer another cuppa at the vital moment😉 JFF stick a servo in the RX and try it. You may get a pleasant surprise. If you don't - nothing lost. If you do - have fun with it. Good luck. Doug 😎 PS Re PTB; when I started I thought it would just be a Cosmetic job; clean up flat back and respray in Pacific green camouflage. Ho ho ho! After I got started I found some curiosities in the construction and that the prop tubes and rudder stocks were misaligned. Never mind the ESC that burst into flames when I tried an 'as bought' test. So from then on it was clear that I had a full rebuild / reno. on my hands. "Hey ho hey ho it's off to work we go"!😉 All old paint now off, chine rails repaired / replaced and first coats of resin and tissue strengthening applied. Might get to the priming tomorrow or Sunday.

Seaplane Tender 360 by RNinMunich Fleet Admiral!   Posted: 2 months ago
Hi Bryan, If you want to do the SOE version she was most likely painted all matt black! The colour of skulduggery 😉 What ever you do, despite your good intentions to retain the 'old patina', judging by the photos you are in for a complete strip back and redo. Just as I have discovered with the PTB I bought. Thought it would just be a 'cosmetic job', flatten back and respray with Pacific green camouflage. Ho ho ho! Pics show what she currently looks like after cleaning off layers of enamel, and discovering that the prop shafts and rudders were misaligned and the chine strakes glued to the paint. 😡 Never mind an engine room fire when I tried to test the 'as bought' motor installation. 😭 Since those photos I have fitted new a new chine strake and started reinforcing the thin hull with glass fibre tissue. Next issue; set prop tubes properly and make an alu bracket to mount both the motors. Then set the rudder stocks correctly. Last thing I want is to dampen your enthusiasm, but that hull looks like it needs oodles of TLC. 🤔 Be aware of what's ahead of you and plan accordingly👍 Deck looks pretty neat, if unusual for a WW2 in service boat! As far as I can tell from the photos it's not just the cabin roof which is warped 😲 cabin and window frames will also need some attention by the looks of it. Before you run that motor I would strip it, clean all parts and check brushes and commutator for wear. See my Sea Scout blog 'Taycol Target motor' for a 'How to'. Should run well with a 3S LiPo, 11.1V. These boats weren't the fastest, 28 - 30 knots I believe. Which is why ST360 was reduced to more mundane duties after try outs by SOE. Don't forget some spark suppression!! Good luck, whatever you decide to do have fun doing it, Cheers Doug 😎

Fittings & Detail Parts by pittsfieldpete Lieutenant   Posted: 2 months ago
Thanks, Doug. I’m glad I posted my erroneous method for calculating scale speeds, otherwise I wouldn’t have learned the correct way to do it. Looks like I’ll be eating crow for dinner tonight with humble pie for dessert. It just shows how much I have to learn. I never would have guessed that the prop tubes in our HE tugs are plastic. At first it struck me as a poor material for the job, but from another perspective I guess it’s not so bad. At least the shafts themselves are metal & there’s a nice set of brass counter-rotating props on the business end. By the way...what’s a moorhen?

Fittings & Detail Parts by RNinMunich Fleet Admiral!   Posted: 2 months ago
Hi Pete, glad my memory wasn't playing tricks on me 😊 Re Scale speed. 31fpm?? We'd be overtaken by any self respecting baby Moorhen!🤔 Scale speed isn't simply real speed divided by model scale. More the square root of the scale (expressed as a fraction) multiplied by the real speed. For our tugs this is thus √(1/36) x 11= 1/6 x 11 = 1.83kn or 2mph. Giving a scale speed of around 176 fpm. BTW: you made me curious about the prop tubes in my Southampton! Thanks for the prompt👍 Careful scratching revealed that they are plastic! 😲 Possibly with PTFE ends, at least inboard. I don't think they are made as or intended as sleeve bearings. That would introduce too much friction over the whole shaft length. Generally I believe there is at least 0.5mm clearance in small scale prop tubes. That's the way I make mine for 'Plastic Magic' projects anyway 😉 I also concluded that oilers in these tugs would be useless; a) cos they're plastic, b) cos they are horizontal. So just a non-mineral oil based light grease at the ends! 👍 Cheers, Doug 😎

Fittings & Detail Parts by pittsfieldpete Lieutenant   Posted: 2 months ago
You’re right, Doug. Lithium shouldn’t be in contact with pond or lake water, even in tiny amounts. I feel like a dope for considering lithium at all because for 20 years I designed & detailed water treatment equipment designed to remove that kind of thing! I took another look at my N scale maintenance supplies & it turns out that the grease I have is the PTFE/Teflon type as you mentioned. Another thing you mentioned about lithium grease that’s also true is that it does indeed tend to clump & become semi-solid over time. So obviously lithium grease gets crossed off the lube list. I don’t think the Hobby Engine prop shafts have bearings. It looks to me like the shafts just pass through tubes, essentially using the tubes as long sleeve bearings. When they’re greased they turn quite freely, plus the grease blocks water from entering the boat. There aren’t any oil tubes in my boat, either. Like you (& I assume just about every scale boater) I like to run at scale speeds. Anyone who has ever seen a real tug moving along knows that they can’t exactly reach planing speeds & they’re not likely to be seen towing water skiers. All things being equal, the WYEFORCE tug, which definitely appears to be the boat Hobby Engine designed their models from, has a top speed of 11 knots or 1114 feet per minute. The model’s scale is 1:36, so it’s top speed should be 0.306 knots or about 31 fpm. I don’t think the model can run that slowly, but again I say it’s about having fun. I won’t lose any sleep if the model has a faster scale top speed than the real boat as long as it looks good doing it.

Fire Boat (crash tender) colours... by RNinMunich Fleet Admiral!   Posted: 2 months ago
Evenin' Martin, just a quick thought before I hit the hay! For the non slip deck paint why don't you cover the deck with a suitable wet and dry paper? 😉 With a bit of luck you might even find some wet n dry the right shade of grey!! Don't know the size / scale you are building but maybe around 120 / 240 would do! Cut to fit, glue it down with a spray glue, I found some in the 'Creative Corner' of a garden centre near me. Also a good source of fine gauge steel, brass, copper, gold and silver wire and nylon thread, and anchor chains😉😊 Then seal with a spray-on flat sealer or varnish, then spray a satin colour you want. Humbrol H129 might be a good substitute for 'Cerrux Deck Grey'. See Model Boat Mayhem for references to Cerrux Grey 😉 I agree the cabin sides are a much lighter shade of grey, almost white. Just ripped all the innards and deck fittings off my PTB. Just got the bare hull and shaft tubes left. Just havin' a wee dram then up the 'apples and pears to Bedfordshire' before I get tempted to sand and paint through the night. It happens sometimes 😲 G'night all, cheers Doug 😎 ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ

Smoker / Light Contoller by timgarrod Sub-Lieutenant   Posted: 2 months ago
Afternoon All, Really please as finished off the smoker/light controller i've been working on. it works with any smoker that has a fan. theres three version avaible, but all versions have the same light functions, one switch - on /off (can change to a proportional to work with a water pump) Three position Swich, controlls two light circuts or anything. Oil heater, will turn the fan and heater on only when required. saves on Battery and to replicate a diessel engine. Water vapor system, able to turn off/on the power to the system remotely, Diesel engine, will power the fan 100% and the start and the slow the fan down till model is just about to move off. Steam Engine - Fan at idle is about 20% so always push the smoke up but then it will encrease with throttle input. the best thing i think is that any thing can be changed via the arduino. Will be make a few so if any one interest in one, please PM me. this is one i've just made for a friend that use the Oil heater and mine using the water vapor system Thanks