Moderators AY Mod Posted June 18, 2019 Moderators Share Posted June 18, 2019 Latest CAD images from Facebook posts. 7 3 4 Link to post Share on other sites More sharing options...
RMweb Gold chris p bacon Posted June 18, 2019 RMweb Gold Share Posted June 18, 2019 Others will know if the body is accurate , but for me that's quite a gear train ! The motor will have to pretty 'beefy' for that lot plus rods although there is plenty of room in the turbine space. 2 Link to post Share on other sites More sharing options...
RMweb Premium melmerby Posted June 18, 2019 RMweb Premium Share Posted June 18, 2019 10 minutes ago, chris p bacon said: Others will know if the body is accurate , but for me that's quite a gear train ! The motor will have to pretty 'beefy' for that lot plus rods although there is plenty of room in the turbine space. Shades of DJM? I don't like the look of so many gears, I would still favour a gear tower driving the centre set and rods (jointed) to the leading and aft set. That's an awful lot of possible friction. 1 3 Link to post Share on other sites More sharing options...
Miss Prism Posted June 18, 2019 Share Posted June 18, 2019 Oh dear. Another suicidal transmission. 4 Link to post Share on other sites More sharing options...
RMweb Premium melmerby Posted June 18, 2019 RMweb Premium Share Posted June 18, 2019 (edited) 3 minutes ago, Miss Prism said: Oh dear. Another suicidal transmission. From the worm it's eight intermediate gears to the front driven axle's gear! Edited June 18, 2019 by melmerby 2 Link to post Share on other sites More sharing options...
RMweb Gold Joseph_Pestell Posted June 18, 2019 RMweb Gold Share Posted June 18, 2019 Continental HO (and N) manufacturers have used gears for decades without major problems. But I agree, that seems way more complex than necessary. 1 1 1 Link to post Share on other sites More sharing options...
Yorkshire Square Posted June 18, 2019 Share Posted June 18, 2019 I might be wrong, but there is no indication that the gears are used for speed reduction once you've gone past the initial worm/gear. The initial gear seems a similar size to those on the wheels and the intermediate ones are irrelevant. And would the gear onto the worm not be skew cut, or are we working on Chinese-near-enough technology? Link to post Share on other sites More sharing options...
RMweb Premium PMP Posted June 18, 2019 RMweb Premium Share Posted June 18, 2019 It’s an unusual design, and doesn’t look well balanced. I have reservations regarding the gear train methodology, based on DJM experience. The motor to gear tower drive via a universal joint type prop shaft again seems very unusual. Hornby have done a similar thing with the J15, but they have twin flywheels either end of the motor, and a simple gear tower to single driven axle. From the CADs it appears there’s a large area of empty space around the motor and top of gear tower, so relatively little weight over the driving axles. Conversely the chassis appears solid, forward from the leading driving axle. If this is the case then there may be poor weight distribution with too much weight over the front bogie, and insufficient adhesive weight over the main driving axles. With the existing chassis CADs, this one wouldn’t be for me until I see one running. As has been mentioned ‘geared’ chassis’s can work, but they need to be well engineered and assembled. I would have thought a conventional motor to gear tower drive would have been simpler, as reliable, (subject to quality), and cheaper to design and manufacture. 3 Link to post Share on other sites More sharing options...
Stanley Melrose Posted June 18, 2019 Share Posted June 18, 2019 It looks as if it may be possible to remove some of the intermediate gears to leave only the drive to the centre driving wheels . . . Stan Link to post Share on other sites More sharing options...
RMweb Premium spamcan61 Posted June 18, 2019 RMweb Premium Share Posted June 18, 2019 (edited) 2 hours ago, Miss Prism said: Oh dear. Another suicidal transmission. Indeed it's bonkers; looks like one of those school physics test where you have to say which way the end gear is turning. Given less than micron precision machining and wear over time the gears and con rods will soon be fighting each other as the wheels rotate. Use gears or con rods to transfer power to the coupled wheels, not both Edited June 18, 2019 by spamcan61 . 1 3 Link to post Share on other sites More sharing options...
Pre Grouping fan Posted June 18, 2019 Share Posted June 18, 2019 Its been mentioned a lot on the facebook post. With comparison "other manufacturers" design style and how that worked for them. I think its going to be looked into. 1 1 Link to post Share on other sites More sharing options...
RMweb Gold Bucoops Posted June 18, 2019 RMweb Gold Share Posted June 18, 2019 Hopefully - it would be a shame for the mechanism to potentially ruin what looks to be a nice design otherwise. 2 Link to post Share on other sites More sharing options...
RMweb Gold Ryde-on-time Posted June 18, 2019 RMweb Gold Share Posted June 18, 2019 Yes, concern expressed on Facebook regarding the drive train and also the possibility it will have an old style split chassis I find it interesting though that Rapido decided to use a similar drive train on their Ho scale Hudson steam loco, a premium price top of the range product. They apparently decided on the all geared design after testing a series of prototypes. It certainly seems to run extremely smoothly on videos and has had positive reviews from purchasers. It seems then that it is possible to make such a chassis work, we just don’t know whether the GT3 has had the same amount of development or whether it’s just what the chinese design team has come up with 1 2 Link to post Share on other sites More sharing options...
RMweb Gold Enterprisingwestern Posted June 18, 2019 RMweb Gold Share Posted June 18, 2019 I don't know why Keith is bothering! Mike. Link to post Share on other sites More sharing options...
truffy Posted June 18, 2019 Share Posted June 18, 2019 He's bothering because he wants a GT3 himself. Apparently. I can't help but think that even building a kit would be easier, but there you go. 1 Link to post Share on other sites More sharing options...
RMweb Gold adb968008 Posted June 18, 2019 RMweb Gold Share Posted June 18, 2019 (edited) Interesting design, if the “white” is the metal chassis, then the lumpof weight is over the front pony's... wouldnt that be tipping the centre of gravity forwards ? I wonder if using a shaft, having the motor over the ponys, running the shaft to the centre driving wheel and having the weight either side of the other two would have been more balanced ? i dont know if its possible, but if the motor did sit forwards, but lower, over the ponys, it could have a shaft to operate the fan too, and maybe eliminate 1 gear from the tower, or even have 3 gears on a long shaft going straight to each of the axles eliminating the intermediate gears between them ? Though the risk is making the weight above the chassis top heavy, but it could be a monster for haulage. Either way its nice to see progress, should the footplate steps sit so far out..way beyond bufferbeam width, they look somewhat out of gauge ? Edited June 18, 2019 by adb968008 Link to post Share on other sites More sharing options...
RMweb Gold Enterprisingwestern Posted June 18, 2019 RMweb Gold Share Posted June 18, 2019 32 minutes ago, truffy said: He's bothering because he wants a GT3 himself. Apparently. I can't help but think that even building a kit would be easier, but there you go. But then that wouldn't do the rest of of us a favour would it? Mike. Link to post Share on other sites More sharing options...
RMweb Premium spamcan61 Posted June 18, 2019 RMweb Premium Share Posted June 18, 2019 7 minutes ago, adb968008 said: Interesting design, if the “white” is the metal chassis, then the lumpof weight is over the front pony's... wouldnt that be tipping the centre of gravity forwards ? If the white is indeed metal (looks to be that way) then then weight is indeed over the wrong wheels Link to post Share on other sites More sharing options...
RMweb Premium melmerby Posted June 18, 2019 RMweb Premium Share Posted June 18, 2019 (edited) 3 hours ago, Yorkshire Square said: I might be wrong, but there is no indication that the gears are used for speed reduction once you've gone past the initial worm/gear. The initial gear seems a similar size to those on the wheels and the intermediate ones are irrelevant. And would the gear onto the worm not be skew cut, or are we working on Chinese-near-enough technology? There is a reduction from the worm to it's gear, then an increase from that gear to the idlers then a reduction back down from the idlers to the axle gears, so possibly no ratio change between the first reduction and the axles. Edited June 18, 2019 by melmerby Link to post Share on other sites More sharing options...
truffy Posted June 18, 2019 Share Posted June 18, 2019 15 minutes ago, Enterprisingwestern said: But then that wouldn't do the rest of of us a favour would it? Mike. True, Mike. There are just not enough people in this world who just want to do the rest of us a favour. Link to post Share on other sites More sharing options...
RMweb Gold Enterprisingwestern Posted June 18, 2019 RMweb Gold Share Posted June 18, 2019 3 minutes ago, truffy said: True, Mike. There are just not enough people in this world who just want to do the rest of us a favour. Even from here I can smell the cynicism! Mike. 1 Link to post Share on other sites More sharing options...
black and decker boy Posted June 18, 2019 Share Posted June 18, 2019 That looks like a split chassis and potentially stub axle driving wheels, DJM J94 style so potentially very very difficult to re-gauge. as others have said, an all geared mechanism with coupling rods is potentially a disaster and high risk of all the running faults of said J94 Link to post Share on other sites More sharing options...
Bernard Lamb Posted June 18, 2019 Share Posted June 18, 2019 19 minutes ago, black and decker boy said: That looks like a split chassis and potentially stub axle driving wheels, DJM J94 style so potentially very very difficult to re-gauge. as others have said, an all geared mechanism with coupling rods is potentially a disaster and high risk of all the running faults of said J94 What odds on it being the same CAD source and /or even the same factory? It does have a certain family likeness about it. Bernard 3 Link to post Share on other sites More sharing options...
RMweb Gold adb968008 Posted June 18, 2019 RMweb Gold Share Posted June 18, 2019 (edited) 25 minutes ago, Bernard Lamb said: What odds on it being the same CAD source and /or even the same factory? It does have a certain family likeness about it. Bernard Hmmm.... Edited June 18, 2019 by adb968008 Link to post Share on other sites More sharing options...
JSpencer Posted June 18, 2019 Share Posted June 18, 2019 23 minutes ago, Bernard Lamb said: What odds on it being the same CAD source and /or even the same factory? It does have a certain family likeness about it. Bernard If true, as we know DJM fell out with said factory over a year ago, then that would then be proof that DJM is not at all involved here. Link to post Share on other sites More sharing options...
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