How about a 180 (30cc) glow motor?

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I will start another thread re the Russian stuff.

Another thing I noticed was there does not seem to be much surface for a mounting face on the rotor housing to the case - the step in the drawings does not look sufficient - is this an oversight or just my interpretation of the drawings...

I think the OPS 80's use a disk where as the Rossi's and OS engines are drum's. Might need to keep an eye on the FOR SALE forums for a pair of cheapies...
 
Tim,

You are correct, I do not show much step. The idea is that the corners would be extended with either little ear type profiles or just square like that Picco backplate. As I mentioned earlier, there is an awful lot NOT shown on those drawings (like how the cylinders bolt to the lower cases). This stuff is important of course, but I merely wanted to show a quick layout to judge the feasibility and get some sort of reaction. I myself am encouraged by how compact I am able to design it, and I feel it is feasible. Construction details can be thrashed out later if the project goes any further, what I wanted to show was something which gave the size and layout and showed the stuff important for performance. 8)

I know you prefer drums, but my pick of that lot would be the OPS 80's. Craig was advertising Rossi parts before, I wonder if he has a pair of 90's? ;D However to change the disc setup in an A-90 to run backwards simply requires me to clock up the alloy disc on the mill, and drill a single 1.5mm hole. Pity I dont have a pair....

The other alternative is to use a certain pair of K-90's mounted backwards with 180 degree headers. These could be made from old Hanson wrap to centre headers used on Zenoahs, I might have a line on some.

Nitrocrazed racing: Not as silly as it sounds....
 
Tim,

Yep, should be a suitable test bed, although I keep robbing it for parts! The servos are gone, the turn fin is gone, the rudder is on the mono and I just put the strut on the mono last night! But we have the technology to rebuild it! The tanks can hold 30oz, so it should have the fuel capacity. Good rough water boat!

Nitrocrazed racing: I have used a 180 before... 8)
 
Here it says in the rules that engines above 15cc must be run on standard gasoline :p

But a boat like that would defenately be something. 8)
 
Finne,

In Australia our rules allow for a displacement up to 30cc. This has lead to people using two 15cc engines particularly in riggers. It is my understanding that the rules in the US allow for the same thing.

Tim,

You speak of the Picco 90 XP as in the pics:

Ian.
 
And this pic.

That is the cylinder is removable from the case. Yes this is the type of case split I designed as it was the only practical way to do the cylinder porting, considering the case prototype would be machined rather than cast. Also I felt it was more practical to have fully seperate head buttons and cooling jackets because of the difficulty in machining everything fine enough that a single head could adequately seal and get the correct fit in the liners. Plus the possibiltity of differential expansion with heat causing major stresses in the head and cylinders.

The case would not be particularly easy to make as it needs to have all the bores for bearing and cylinders all lined up correctly. But I think it is all within the capabilities I have access to. What are friends for! ;)

I still think the difficult part would be the gears. I was not able to find design guides in my own texts. Due to the lack of interest in general I didn't go to the Uni library and have a look for their texts. Altho gear design is an ever changing science! These gears would need to be very strong and well made to cope with the highly fluctuating loads that two cylinders would put on them.

That said I still think it is all still well within the realms of possibility, and while such an engine would still have two carbs to synchronise and tune, the performance and sound of the engine should be awesome, and it should be able to beat the twins! ;D

Nitrocrazed racing: Build it and they will come....
 
Altimat,

As far as I know the pics were of a prototype engine, but they may be available. I have no idea how you would get them tho! : :)

However the design is quite a radical departure from Picco's previous designs, and now 'happens' to share a lot of design features with CMB 90 Evo 2's. : :) I guess it was a case of "If you can't beat them, join them!" The two bearing double sided crank with steel rod and needle bottom end, zimmerman disc induction, bolt on carb with integral 3rd channel mixture, AAC P&L are all features of the CMB's. Also worth noting is the taper on the end of the crank. This IS different. What it means is that the flywheel cannot pull up on the front bearing, so any thrust on the flex hex will push the whole crank. The bearing at the disc end would have to be a needle roller like the CMB, and thus is incapable of taking end thrust. I would say the engine is designed for European Multi racing where the solid shafts incorporate a bearing arrangement to take the prop thrust. The engine may be suitable for square drive use.

But I honestly think you would be better off with the CMB 90 EVO 2 if you like the design! ;D

Ian.
 
Ian,

Radical departure for Picco??? Hmmmm since I believe Mr Picco was originally working for OOPS, I mean OPS, the similarity to the OPS 90 takes some shape? Yes most of these 90s seem to be built for Multi (FSR-V) or any other name we care to give european racing, but to reccomend the CMB over this engine? I dont think so.

Check the porting out!!! My main criticism of CMB is the awfully large boost port in a 3 port engine. 4 port or 5 port in my book will perform better. So a 5 port in this 90 should be better than the CMB. Lets just hope Mr Picco doesnt have a weak link in the machining like the later EXR engines.... no wait... lets hope he does so I sell more A90s!!! LOL

disclaimer - please dont anyone take me seriously there

EMS Racing maybe I should shut my big mouth?
 
Craig,

I was mostly referring to the crank and bearing layout when saying it was a radical departure for Picco. The upper case split is an idea used by the OPS 90, but I think it is on this Picco so that the user does not have the CMB EVO fun of pulling circlips and wrist pins out thru the exhaust port! :eek:

Not sure about port numbers. Andy Brown could have had CMB make anything he wanted for his MAC engines, yet he does it with 3 main transfer ports (and two sub piston ports on some, but ignore that for the moment). It is not like CMB can't do more complicated porting, witness the various CMB 21s. But the generally agreed pic of the 21 bunch is the MAC 21, a 3 port motor...

I didn't even want to touch on the reliability issue! Apparently the prototype engines blew up and got packed up in a hurry.... :-

Nitrocrazed racing: trying to be fair...
 
Ian,

3 port is easier to optimise simply. More ports more variables so the amount of work to get a 5 port engine may me much more. Think about manufacturing costs and how easy it is to adapt the existing CMB engines to MAC engines tooling wise.

And just another curly one to throw in.... Andy may have had most of his experience in starting with 3 port engines and modifying, as most engines have been 3 porters. Maybe his expertise is in optimising the 3 port configuration, so his engine may follow that formula. Think back to the 5 port Rossi 45. Absolutely ballistic motor with the right mods (unfortunately that meant lowering port timings so almost impossible for the average boater). My old Rossi left EVERYTHNG for dead a few years ago. No boat ever beat me to buoy 4 from the start. If only I could have kept the boat right side up!!!

EMS Racing to finish first the prop really should be in the water most of the time.
 
Craig,

Possibly there is something in that. I dont think the cost of mutiple ports would put Andy off for the MACS.

The Rossi style 5 porting on my K-90 is yet to outpace my 4 port A-90's, but as you say, maybe it is harder to optimise more ports. :-

Nitrocrazed racing: Where was that dremel....
 
Last edited by a moderator:
Did we ever get the time/ area calc's for the A100 Vs K90?

Ian,

I doubt the gears will be a problem - we are ONLY (he he he ) talking about a MEASLY 15HP ;D

I'll ask the guy who cut my 21 gears what he thinks.
 
Tim,

No, Mark didn't get a chance to do them, and I haven't heard from him in ages. :- I guess one day I should work it out for myself, but I am reasonably convinced that the rev limit problem was not related cylinder port time area issues.

As a proffessional Mechanical Engineer I DO think the gears will be the problem! :p : :) At any one time only one or two gear teeth will be taking the full load from one cylinder at a radius less than that of the crankpin, so the forces are even higher! I think to get any durability the gears would have to be hardened correctly and ground. I doubt hobbed gears would do the trick. But see what he says. Just remember the consequences of a sheared tooth or two in a fully enclosed system.... :eek:

I think the gears ARE do-able. Just they will cost a lot too...

Nitrocrazed racing: I need MORE power!
 

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