RE: Roots Type Supercharger
The power valve I refered to in an earlier post was based around the Yamaha system from days gone by (the 80's, some great electronic music and loads of freedom - Happy days) anyway, the Yamaha system did not effect expansion chamber volume, it altered port height, so, it was very effective in creating a docile higher torque motor below 3K RPM when the PV started to open, but the engineers were still able to have a screamer above 6K RPM when the valve was fully open. Kawsaki, Suzuki and Honda tried their versions and never beat Yamaha, only Aprilia ever got something better - and that cylinder on the RS125 is something that should be a base reference for all engine design (2 stroke) to come. It's all relative as the materials technology now is so much better that we could have seen a whole heap more from two strokes before they were stopped. Mark my words - they will return. However, back onto the supercharging subject, I think it can be done if you are clever enough, but I also think that you will struggle to achieve power outputs matching the stock output. As you seem to be looking for looks as well as functionality, is a "scale" model SC not something you could create and mount on top of your motor to look authentic? Glenn
Posted on: 9/9/2012 4:41 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11223089

RE: Roots Type Supercharger
Glenn- I have seen simular done on nitro boats but without the water. Seen one that had a adjustable pipe, and a 3rd channel mixture control. Both the pipe and the mixture control workeed together, I am assuming as the turn would approach the pipe would lengthen and fatten the needle up for good power out of the turn then on the saw shorten the pipe and lean her down! I could see that being a nightmare to get setup and working right! [/quote] The best way to do it, but would need some electronics would be to have the pipe length control servo controlled by an engine rev pick up unit, as the revs rise across a range, pipe goes from long to short at max revs, hopefully following somewhat the torque curve of the motor and thus adding perfomance across a braoder spread. Need an electronics boffin, though it would not be that hard to do. Guess the ultimate would be similar to the old two stroke bike power valve systems where revs and throttle position were measured and the power valve is adjusted to suit. The mixture should not be too much of an issue, the carbs stay fairly consistant. "I also realize that a 4-stroke would be easier, But that is not the "look" that I want. And I realize that RBInovations has a centifugal type supercharger but this again is not the look I want. This is more about the look than the amount of boost I will get. I do want it to boost power and by doing this I may stumble across some solutions that have been a problem with supercharging 2 stroke engines. I am sure that I will have alot of problems to overcome. " The biggest problem to overcome is going to be the fact that you are going to be trying to pressurise the crankcase then as the transfer ports open, a lot of that pressure is going to force a disappearing act out the open exhaust port. I think that you are going to have to make some pistons to experiment with the timing to get this to work. But all part of the fun. Glenn
Posted on: 9/6/2012 4:41 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11220033

RE: Roots Type Supercharger
If you are going to go to the trouble of making a supercharger (a massive undertaking), why not try and fit it to one of the proprietry available four stroke engines that are around? Thinking one of the Honda GX series or similar. If you are able to make a supercharger, then the engineering required to modify the engine to handle the supercharger would be a (relative) walk in the park. I would like to see and hear one running. Om the subject a few posts up on power valves, I do know of an experimental system in existance that alters the tuned pipe length on a slip coupling as revs increase, and I know the SAW runners use water injection at lower revs to fool the engine into thinking the pipe is longer to get a little more low end power to get the big props turning, the water is knocked off when the boat is moving fast to then simulate the shorter pipe and restore the tune for the max revs. Good luck in whatever you do though. Glenn
Posted on: 9/5/2012 4:48 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11218786

RE: Stuff tube help please!
Are you sure that you have a correct direction flex shaft in there? Reason I ask is that normally the shafts are wound so that when running, the grease / oil in them is driven down the shaft to the stuffing tube, and also so the shaft winds tighter as the torque being transmitted down it increases, if yours is drawing the brass liner up to the engine, it would appear that maybe your flex shaft is the wrong wind on it. Hope this makes some sense. Glenn
Posted on: 9/3/2012 3:43 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11216105

RE: Prestwich Makara with Zen7 anyone?
Should be good, I have two Makara's, though not Prestwich ones, but I assume they are the same. Both fly and are very good rough weather boats, I found they run best with some serious power, running big bore long stroke motors in them and getting just on 50MPH now, which is pretty good for a big model. I am sure that you will have fun with it. Glenn
Posted on: 8/3/2012 7:44 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11180275

RE: G6 rigger finished.
Loks nice. Will be good to see it go. Strange, but whenever I look at peoples work areas, mine inclued, there always seems to be a small hammer laying around somewhere close by!! Enjoy the rigger, sure it will be a rocket ship. Glenn
Posted on: 7/11/2012 5:10 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11151882

RE: swashdrive jetboat
Nice and tidy. You might find the engine has a problem with the carb cover on, if it starts a kind of surging on and off behaviour when running at high revs, take off the cover and try it. Let me know what you think of the Jettec unit, Adam seems to do nice work. Glenn
Posted on: 6/25/2012 6:51 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11131842

RE: Pipes
[quote]ORIGINAL: Jackal1983 Yes it very simlar to the apache Hull.. What kind of speeds are people getting out of the Makara, Apache hulls? yer i know pipes wont make a great deal of diffrence but i just like to experiment with different set ups! [/quote] I hit 52 with mine on GPS with the 30.5cc big bore. Try not to get too hung up on top speed on these, set it up for good acceleration off the turns and stability and you will have a great time with it, it is the one boat of mine that just runs in any weather, great fun and never get bored with it. Pipes actually do make a good deal of difference. One thing to be wary of if you run the top on yours is heat build up from the pipe is significant, I wrapped my pipe in fibre rope to reduce the effects, plenty of ventilation needed. Glenn
Posted on: 6/25/2012 6:45 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11131830

RE: engine
Ditch the clutch. But - I realised, you have had a load of advice, and even a really good offer and yet you are still trolling around. You have had the answers you need, you really have, the advice you have had has all been top notch too, not one scrap of duff info. Your mind should be made up. G
Posted on: 6/24/2012 5:06 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11128441

RE: Pipes
I'll email you a photo Henck, basically an apache.. Glenn
Posted on: 6/22/2012 9:05 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11128437

RE: Pipes
Try the CS24a pipe, very good. Thats a pretty good speed from a Makara that you are getting there, we have two fast ones on our lake and both are running 30.5 Zenoah based motors. Glenn
Posted on: 6/21/2012 5:10 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11127098

RE: engine
Of those two, I'd prbably got for the RCMK as it is lighter and the Rio will not like the weight of the old QD. Can you not find a modded Zenoah secondhand going cheap? Glenn
Posted on: 6/21/2012 5:03 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11127093

RE: Flex Shaft and how accurate but should be?
I would realign that to be a smooth in and out into the collet. Should be easy to do, either shim the engine across as needed or if you are using a tee bar shim the prop tube across. Glenn
Posted on: 6/5/2012 3:06 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11107725

RE: best motor
[quote]ORIGINAL: rio 51 racer alright i also need a new rudder?? Which one [/quote] I think you might be missing the point completely, do yourself a favour and read all of the posts in this thread so far, there is no bad advice there, but maybe some you don't want to hear!! Scott maybe had the best option - move this package on and build something from scratch or get a rigged model ready to go or needing work. Over. -And out. Glenn
Posted on: 5/31/2012 5:05 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11101740

RE: best motor
[quote]ORIGINAL: rio 51 racer So which of those motors is best [/quote] That's the age old question to which you are unlikely to get a definitive answer, it is all opinions. All the motors you list are able to get the Rio to (and past) 50MPH, but the speed is in the set up, my advice would be to try and steer yourself away from speed targets, rather start to try to get the model running reliably first, new motor and drive line, then the steering hardware and I know some end up refitting the radio gear. Then, as your boat gets better and you work out the set up, the speed will come to you but hopefully a nicely handling hull will evolve with it. I have had 50MPH plus boats in the past that were a real pain in the neck to run, often they would be doing 50 upsdie down and 6 feet above the water - no fun, but I learned the hard way I guess. If it were me in your shoes, I would look for a good used motor to get you going, plenty about. Zenoah, RCMK and Quickdraw are all good motors with easy spares availability, I'd be looking for a used one of these motors. As Scott Schneider said though, doing as much work as you are proposing to, you might be as well to build yourself one up from scratch. Glenn
Posted on: 5/31/2012 12:32 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11101463

RE: steps boat that I design in 2009
[quote]ORIGINAL: HendricX [quote]ORIGINAL: c.k.y. I also have long black hair , ha ha You will go to the German race ? [/quote] For me that was 20 years ago ... hair-color ... ha ha I'll be in Germany , as technician for my apprentice Kees Zwartbol , and to watch. As Peter Inglof and I are the only white haired/bearded persons overthere , I'm easy to find. :-) [/quote] Unless Dave Marles grows a beard Henk!! Glenn
Posted on: 5/27/2012 4:46 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11096620

RE: steps boat that I design in 2009
Picture four of Ian Folkson looking very young!! Glenn
Posted on: 5/25/2012 5:30 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11094790

RE: RE:27cc CMB engine
A good strong looking crankshaft, which bodes well. I really like your cartoon of yourself Chan, that made me smile. Good effort. Glenn
Posted on: 5/25/2012 5:26 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11094789

RE: steps boat that I design in 2009
You must be one of the first people in Hong Kong to have one, let us know how it runs. I have seen one and it looks like a "proper" race engine. Have you modified yours yet or are you going to run it stock? Glenn
Posted on: 5/23/2012 4:57 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11092270

RE: ZenoaPUM 26cc carb settings needed
Some nice models in the line up, all seem in very good condition, mine don't look that good when they are new!! Glenn
Posted on: 5/23/2012 4:55 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11092268

RE: ZenoaPUM 26cc carb settings needed
He won't unless he takes a boat with him Chan!! I am just curious to see what the problem is with his engine, can't be too much. Do you guys run FSRV at your water at all? Glenn
Posted on: 5/22/2012 5:11 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11090980

RE: ZenoaPUM 26cc carb settings needed
Good to have some experience, the carbon kevlar boat in picture three looks familiar! Hope you get running soon Richard. Glenn
Posted on: 5/21/2012 1:19 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11089149

RE: Zenoah Running Hot...
[quote]ORIGINAL: TheFridge189  Hi all. I have an all stock zenoah 260. I have a clutch and pump. I had my boat idling for about 20 minutes today, however I took 2-3 minutes breaks every 5 or so minutes.  This was all idling in my pool. I have a waterpump of course. I had one pickup run directly to the head of the zenoah, then directly out the transom. By the end, the water coming out of the outlet was hot to touch. Like, really hot. I couldn't comfortably keep my hand under the water spitting out for more then 6-7 seconds. Any idea's? My pool was 77 degrees when I did this and it was 83 degrees outside... Could that be it? Or should I look into getting a different cooling jacket? Or is it because I am straight up idling, and no substantial throttle inputs? Or is this normal? The water spitting out of the other outlet was quite cool. [/quote] Idling for any period is a bad idea, does you no good and only damges engines - and wastes fuel. If the water coming out of the engine after cooling was liquid then you do not have a problem (IE it was not steam) Better off when you get it out of your pool and on the water where it belongs run it for 5, bring it in, touch the head carefully, if you can keep a finger touching the head for about 4 seconds then you are laughing fishcakes, all is well and the engine is about 70centigrade. Don't overcool an engine. Glenn
Posted on: 5/11/2012 6:58 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11077531

RE: Receiver/servo/enigine issu
Most likely is RF interference caused from the High Tension side of the engine ignition, use a supressed spark plug cap, ensure all the engine ground return paths are clean and good. Glenn
Posted on: 5/1/2012 4:45 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11064566

RE: Prop Choice
[quote]ORIGINAL: Jackal1983 HI Bob. Ive been my pipe was my first choice. I changed from the bindi quite pipe that's the split able alloy lump to a prestwich pipe. Doesnt seem to of made and difference except its a tad louder... Lol.. Maybe I need to reduce my pipe length from 13.5'' but I'll play with prop heights. [/quote] I run at our local lake in Sunderland, the website linked here shows a map of where we are. http://www.herringtonmodelboatclub.tk/ We have a race series for some sport and fun around the buoys on the lake, nothing too serious though. As to your symptoms, a pipe too short would cerainly not help, try and set it for an initial settign at 340mm from the flang face of the exhaust port to the fattest part of the pipe, generally a good starting point, and don't forget to chop off any extra header hiding inside the pipe. Modding the hull to get the prop centreline higher should take two minutes once the strut / stinger is out the way, use a rough round file and file a slot up the transom, then slot the screw holes too. Bolt it back up, set the height, shaft in, rev up and go. Glenn
Posted on: 4/30/2012 6:22 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11063317

RE: Prop Choice
Indeed. And it helps with the handling. Guess you too are washed out today? Glenn
Posted on: 4/29/2012 8:36 AM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11061180

RE: Prop Choice
[quote]ORIGINAL: Jackal1983 That makes sence dan... Thats why its only reving fractionally higher with the 7015/3 on it! I think the X470 will be an inprovement I thought a BZ4 Zen would of turned a 7015/3 easily... I guess not! [/quote] I run a few Makara's and with 26cc motors run a 7015/3 on all of them, I have yet to find a motor that won't turn one, obviously, the more power the motor has the faster it'll turn the prop, but overall I ifnd the 7015/3 hard to beat as a mono prop, very little prop im[act ont he handling of the hull, from my experience so far. One thing that most likely is worth checking when running the 7015/3 is the strut or stinger position, I have had to raise the centreline of the drive to allow the engine to pull the 7015 properly, and on most of my Makara's I run with the centreline of the drive shaft 13mm up from the tip of the vee on the bottom, you can go a little higher if you like. Start with this set up and the pipe length around 340mm and shroten from there, so long as there is nothing wrong with the motor then it should be able to spin that with ease. Let us know how you get on though. Glenn
Posted on: 4/28/2012 6:48 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11060645

RE: ZenoaPUM 26cc carb settings needed
[quote]ORIGINAL: richardclausen Hi Glen not sure which carb you have, but try needles first at 2 low and 1 high. Put your finger over the carb inlet and choke it, watch the fuel go up the fuel line. Two slow pulls like this, and your finger should be wet. What does 2 low and 1 high mean? Turn the ''L'' in fully and then unscrew 2 full turns? Thanks Rich [/quote] # Hi Rich, yes, "gently" turn the screws in clockwise until they stop - be very gentle as the needle seats are soft and easy to damage, then unscrew for the two turns on the low and one on the high. If it's a 257 carb that will most lilkely be a little rich, but should get you running, rich is normally safe. Just ppicked up on what Ian mentioned and he is correct, a bit more oil would be good, around 16:1 keeps them running well. Everyone has their own views on oil content though, so don't get too hung up on that for now, oil content won't affect your starting, unless you have way too much oil in there of course. Glenn
Posted on: 4/28/2012 4:40 AM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11059871

RE: ZenoaPUM 26cc carb settings needed
This is somehow a double posting which needs to be combined. Dan's advice is good but maybe these two threads need to brought together to get the info out there when the final problem is identified. G
Posted on: 4/27/2012 6:25 PM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11059550

RE: ZenoaPUM 26cc carb settings needed
Hi Rich, not sure which carb you have, but try needles first at 2 low and 1 high. Put your finger over the carb inlet and choke it, watch the fuel go up the fuel line. Two slow pulls like this, and your finger should be wet. Now, give it some throttle, about 3/4 so it has plenty of air, a good strong pull and you should hear it fire and hopefully start. Might take two or three tugs but should clear the excess fuel and get to firing within three to five pulls normally. If its a 644 carb you might want to try needles at 11/2 out each and repeat. Make sure the motor is not flooded, and that your radio is opening and not closing the throttle. Let us know how you get on. Glenn
Posted on: 4/27/2012 11:46 AM by Author "glennb2006" in the forum "Speed - RC Gas Boats"
http://www.rcuniverse.com/forum/fb.asp?m=11059169