posted
may be in 19 days???
Posts: 14 | From: nj u s a | Registered: Nov 2003
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Badger
unregistered
posted
19 days? What does that mean? Does it mean that it will be out in 19 days or we get teased again then?
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macmaxx
unregistered
posted
hello to everyone,
first...that are really great news
one questins...how it would be if you design a special pipe for the bigger ccm's?....so we dont need to buy for example a waller adaptor, or something like that....the "new" pipe alos dont needs a spzial efra#
posted
i dont work for rb or do i know any body who does but i think well see some thing on or around 19 days
Posts: 14 | From: nj u s a | Registered: Nov 2003
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posted
I have seen some of the .26 rated @ 2.7hp. But hey, this is an RB .28 engine, sooooo ya know it's going to beat that easy. Posts: 1 | Registered: Apr 2004
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posted
Easy guys ...... I don't remember them giving us a time frame. I remember Rody saying they had some last minute changes. What's 15 more days, as long as the engine comes out right! Posts: 1 | Registered: Apr 2004
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Corrado
unregistered
posted
I can wait, as I know it will be well worth it. RB's are more than worth the wait, and the price...
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posted
There already out... If your talking about 1004-S5 there already out and people have them..
Posts: 1 | From: Wisconsin | Registered: Mar 2003
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posted
Just a quick question for Rody if he's about ? Thanks for doing this engine at last, no more dodgy p/s RB .21 conversions, but is there ANY chance the pullstart will be compatibe with any of the available rotostarts ? Im sure iv heard that the rotostart will fit the Hyper 21 engines, which means it should fit a p/s converted RB .21, so considering crankase size in the .28 is normal RB .21 we may be in with a chance ?
Im sure it'd be hugely popular, everyone i know who runs a savage with the .25 or picco .26 fits the rotostart & i know a few people wont buy a Sirio .27 because it's not rotostart compatible.....
posted
Yes please roto-start compatible would be excellent.The roto-start is one of the most convienent new things in nitro r/c to come along in a while.Even if the hpi,hot bodies, or ofna backplate is not compatible you guys could always make your own back plate to work with the roto-start dog bone.(and just use the starter unit itself from hpi,hot bodies or ofna). PLease,Please,Please. Posts: | From: university place, Wa | Registered: Apr 2004
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posted
Man I cant imagine tring to pull start an RB My WS7 will stall my starter box.(I feel some blisters coming on) The pain will be worth it though. I cant wait Posts: 4 | From: Mission B.C. Canada | Registered: Aug 2003
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Badger
unregistered
posted
I wouldn't bother with a rotostart. I am sure that you will get your fair share of blisters during breakin but it shouldn't take more than one or two pulls to get it started after the intitial breakin. Rotostarts are the main reason that most go through one-way bearings. This things going to have more compression and if you crank on the rotostart your going to blow a bearing even easier. Even worse is if you have a flooded engine. Pullstart is the way to go. Just my 2 cents...
posted
my rody tuned c5 starts in 2 to 3 pulls now that it has 2 1/2 gallons thru it.... well, it always started in 3 or 4 pulls, just had to use the heat gun to reduce the pinch a little...
posted
I have a C5-B that I modified myself for p/s at first, and this engine is now used in conjonction with a HPI rotostart.
1- I have had many problems for the break-in. In fact, I gave-up to try to break-it with the pull start. I had to mount my C5 on my buggy in order to be able to use my trusty twin-motor starter box to start it for the very first time.
I can tell you that I see a lot of problem to break-in a RB engine with a pull start. The RB engine sleeve/piston fit is one of the tightest fit I have ever feel and believe me, that wasn't my first engine break-in !
Considering the fact this oversized RB engine is not geared toward the hardcore racing guys but more likely toward the basher-beginner type of guy, I would recommend to RB to have a very well documented break-in process (i.e. use of hair dryer, unscrew plug 1/4 turn, do not pull the cord all the way, never try to start a flooded engine ../..)
2- A rotostart is an excellent option.
Nevertheless, I recommend to RB not to use a one-way system in conjonction with the rotostart, the one way has ALWAYS been the "weakest link".
I would suggest to RB to be very carefull when they design the p/s and use NOTHING but the HPI flywheel design that has a spring loaded pin with a slope on the flywheel.
This HPI design is excellent because it allowed me to replace the one-way with an machined hexagon that has a screws that goes straight on the flywheel.
I know it is difficult to explain, but the flywheel slope and the spring loaded pin is what disconnect the pull start flywheel from the crank.
If you look closely at the HPI pull start system, you can figure out that the one way bearing is only used for the cord to retract inside the pulley...
Sorry for the long post, but I though I would mention that to RB so that they do the right move with the p/s and rotostart...
I put a lot of tough into the HPI pull start and the special piece that allowed not to use the one way with the rotostart.
For your eyes only, drawing of the special piece that replace the HPI one way bearing:
(I know there is already quite a few ppl that used my idea and started machining that piece, I should have put a DFF trade mark and logo on it LoL)
There is a need as well to dremel a flat on the pull start flywheel to have the head of the M4 screws to sit properly on the shaft.
DFF
[ 17. February 2004, 22:43: Message edited by: DFF ]
Posts: 28 | From: Toulouse, France | Registered: Nov 2002
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posted
The design of the HPI pull start flywheel - watch the milled slope "bean" on the flywheel face
That's where the spring loaded pin located inside the crank journal catch - see how it works only one-way: the pin will catch the little "milled shoulder" on his way, but when the engine will be started it will slide along the slope (very clever and simple piece of design if you ask me !)
DFF
[ 17. February 2004, 22:27: Message edited by: DFF ]
Posts: 28 | From: Toulouse, France | Registered: Nov 2002
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posted
View of a complete rotostart system - watch the gear piece at the bottom of this picture, the one with the inside hexagon, that's where the one way bearing (or better, my special piece for that matter) goes -
BTW, admin, I alreay apologized for the many replies and pictures posted. I understand it might breaks your board rules but I though showing the guts of the roto / pull start was the only way for me to explain why you need to stay away from the one-way bearing that would do nothing but will either break under the rotostart torque or will no be able to catch the flywheel shaft because of oil that might goes inside the bearing.
I am only talking from experience and I am sure ppl that have use this rotostart system can back-up my words...
Hope this helped !
DFF
[ 17. February 2004, 22:35: Message edited by: DFF ]
Posts: 28 | From: Toulouse, France | Registered: Nov 2002
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posted
Thanks for the info and it is taken into consideration. However we have for this moment opted to go for the same system we are using actually for our .12 pull-start engines which is in combination with a one-way bearing. However we will see what is possible for the future to change or not depending on the reliability of our actual starter system we want to use now.
posted
Rody, does that mean there will definately be no rotostart compatibility ? or just that you will not be using "DFF's" one-way removal idea ?
Thanks
PS - just as a matter of interset im going to do a poll on the UK's premier monster truck website to gauge pullstart vs rotostart preference....
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posted
Never had a problem breaking in RB motors modded with pullstarts. My Rody C5 started on the first baby tug and I never looked back. Pre-heating being super critical for a successful break-in on high end pullstart motors for sure. At least for me. I had to pre-heat for the first 10 tanks of use/break-in then after that never a issue. I never had to loosen glow plugs or any of that either. Even in the buggy with RB motors I pre-heat regardless if my box would turn it over or not. Just less stress on the rod and components doing that with any new motor.
Tom.....
Posts: 1 | From: San Diego, Ca | Registered: Dec 2002
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I took a look at the RB .12 pull start system and I can already say that the RB system is very close to say an Ofna 8 port p/s system.
This kind of pull start is good, but it is unfortunately not compatible with the rotostart (to the best of my knowledge)
To my opinion and according to my experience, the HPI p/s design is far superior...
See this picture from the R&B p/s system and see how the piece 1700-155 takes the crank journal in between the "slot" it has. It means that the piece 1700-155 is always rotating with the crank.
It translate into less performance because there will be more rotating mass since both the crank and the 1700-155 pieces are rotating at very high rpm.
Now get back to the pictures of the HPI p/s and you will understand that the HPI p/s flywheeel does NOT rotate at all when the engine is running. It's simply because of the "milled inclined bean" and the spring pin system that disconnect AUTOMATICALY the flywheel p/s from the crank.
That is the beauty of the HPI design compared to the Ofna / R&B design. The HPI design is simple and very effective (less pieces rotating)
On top of that, with my special piece on the HPI p/s device, you can throw the one-way bearing in a trash bean, and that is in my book a giant step toward reliability and effectiveness of the rotostart system.
So, I am sorry to say but not all pull-start system are equal and I hope the new oversized engine from R&B will use the superior pull start system.
Special note: I hope I did not offended Rody by saying the R&B p/s was an inferior product, I was just saying that there is, to my opinion, better system elsewhere.
Hope this helped everyone to understand a bit better the difference in p/s mechanism !
DFF
[ 18. February 2004, 19:37: Message edited by: DFF ]
Posts: 28 | From: Toulouse, France | Registered: Nov 2002
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posted
i like the HPI p/s but i think i missed something. Exactly how does the spring loaded catch pin in the crank journal work? does it hit the p/s flywheel on each rotation of the crank?
posted
Sorry, I know it is difficult to explain how the HPI p/s system work.
When you have both the HPI and the OFNA p/s system in hand, it is way easier to figure out !
Anyway, watch this picture of the HPI p/s.
Do you see the pin and spring that are located inside the crank journal (p/n 1433)
Well, if you look closely at the previously posted picture of the HPI pull start flywheel (p/n 1432 on my last picture), you can see the "milled inclined slot" on the face of the piece.
That is where the spring loaded pin goes.
So, it means that when the pull start flywheel turn clockwise, the pin is engaged against the "step" of the bean shaped slot.
On the other side, if you turn the p/s flywheel anti-clockwise, then the pin slide on the inclined "hill" of the bean and can't be stuck. Then it continue sliding on the flat surface of the p/s flywheel and then "click" it goes from the face of the flywheel to the inside of the bean still without being catch.
Did you get that ?
Then if you get that, you understand that this system only work one way and that when the engine is running the spring loaded pin disconnect the crank from the p/s flywheel.
During engine running, the pin only slide against the flywheel p/s surface and goes inside the milled bean.
Anyway, sorry for my very bad explanation, but that is the best I can do !!
DFF
[ 18. February 2004, 20:52: Message edited by: DFF ]
Posts: 28 | From: Toulouse, France | Registered: Nov 2002
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I am very sorry to be so insistant and to post so many pictures.
I swear it is the last one and I will not bother you again with my long explanation...
Anyway, for those that still did not understand how the HPI p/s work, here is my last try:
You can see the step on one side and the "no step" because the milled slot bean is around 2-3 mm deep on one side and then blend smoothly with the outer surface of the p/s flywheel.
The green shape shows you the contact path between the pin (pushed against the flywheel by the spring behind it) and the flywheel.
DFF
[ 18. February 2004, 20:47: Message edited by: DFF ]
Posts: 28 | From: Toulouse, France | Registered: Nov 2002
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posted
After one sleeve / piston with my roto and C5, the wear on the p/s flywheel and the pin can almost not be detected.
Only you see a very little polished spot on the flywheel and for sure not a groove !
There is always lubrication (oil + fuel) between the 2 pieces and both are off very high hardness.
You have to try to grind a flat spot on the flywheel to figure out it is not regular steel but more likely something that is over 60 HRC (rockwell) i.e. like a 4140 that has been heat-threated after machining.
And talking about drag, it is no where close in comparison with the Ofna type flywheel:
The HPI has only like a 2 mm pin rubbing against a well lubricated surface i.e very low friction coefficient (the load induced by the spring behind the pin is very low, spring is on the soft side)
against
The Ofna design that has - an extra piece rotating @ 30 000 / 35 000 rpm (extra inertia) - the drag created by the friction of the p/s flywheel inside the p/s cover (no bearing there...) - the one-way bearing rotating on the p/s flywheel shaft - Not to mention the o-ring riding the rotating flywheel shaft
I can't really quantified the net loss of power between the 2 design, but I can only tell you that I can't feel it on my C5 roto equiped engine (I've run my C5 on a bench without the load of the tranny). In real life, both accell and top speed are well preserved.
I would expect this top end to be slightly reduced with the Ofna design, but we would need an engine dynamometer or a very precise rpm meter to measure it.
Anyway, the loss of power is not really my main concern, but the reliability of the system is.
And that's where the HPI design shine big time !
You can take this case for granted...
DFF
[ 19. February 2004, 18:37: Message edited by: DFF ]
Posts: 28 | From: Toulouse, France | Registered: Nov 2002
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posted
DFF if you go back and study the RB and OFNA designs you will notice that the one-way bearing is actually on the inside of the crankcase. Once the engine is up running the shaft going through the back cover is not turning. So the only frictional drag is the one-way bearing, but because this is inside the engine it gets lots of lubrication. The only drawback is the extra rotation weight inside. However I still think this is a better idea on high powered engines than drilling a hole in the end of the crankshaft and weakening the big eng journal.
-------------------- Hong Nor X1CR FTE Powered by 421B, Ofna Pipe Sacker Pro Powered by RB S5, 063 Pipe RB V12 waiting in wings for new ride Posts: 41 | From: Australia | Registered: Apr 2003
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I've never put my dirty hands on a R&B p/s and can't see on the exploded view were is the one-way bearing.
I nevertheless still like better the HPI minus one-way bearing design when it comes to adapt a rotostart system to it.
I can tell you that the little hole in the crank journal doesn't hurt or affect much the stiffness of it, it is a very small hole (around 2 mm) compare to the od of the crank journal.
Take into account as well that material of the crank is very high strenght (and hardness, I know that for sure, I had to buy a special and expensive drill bit to go through it LoL)
For example, on my R&B C5 that was not designed to received such a modification, the crank journal is still in like new condition.
DFF
Posts: 28 | From: Toulouse, France | Registered: Nov 2002
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posted
i had a c4 w/ ps mod, and now a c5/ w ps mod, never any issues, i always use a heat gun during break in, soooooooo much easier
Posts: 55 | From: ohio | Registered: Sep 2002
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posted
Good info guys, I will be beakin-in a new engine today. And after burnning up my starter box wheel the last time, you can bet this time I will be using a heat gun this time around!
i personally hope this does NOT end up rotostart.. rotostart is just one more thing to carry around when i play... already i have to carry the fuel, glow igniter, temp gun, and screwdriver... i am running out of pocket space...
i am over 3 gallons into my pullstart modified c5 rody, and am still on the first 1way and pullstart... just pre heat and it is really not very hard on the starting stuff...
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