Picco .05 first runs
 

Ran 3 bladders through it last night. Very easy to handle, a lot like a larger motor. Easily hand starts front flip or black flip. Has the crank Mods. Needle is very fine thread. Great control.

SIG 25% OS P5 turbo plug, APC 5.4x 2.5, Seemed to be a little over propped. Did not tach it. Only leaned it out for short periods.

Can't wait to get this on an airplane!

MIne is still sitting around in pieces. Afraid to use it because of the weak crank. I wonder what tach reading it would get with a 4 1/4 - 4 APC prop. I checked a bunch of others to compare. They range from 17,000 to 27,000 on 10%. I use 10% on everything because of the rules in the speed class.

Hi Al,

I would certainly expect 30,000 rpm minimum on 10% fuel. The APC 4.2 X 4 is a great prop for 1/2A profile proto. Really allows the engine to rev properly. I wouldn't worry about the crank if you hand start it (or know how to electric start it without being flooded). No point in collecting it for a paperweight. I witnessed the current record holder who used a 3.8" pitch prop at phenomenal RPM. (~ 35,000?) 110mph proto is astounding! However, the next best Picco user ran at 85mph.... Hmmmm, same old story, it's the USER rather than just the engine that puts it all together. BTW, the record models all up weight was 4.4 oz.! Makes my 5.2 oz Shuriken model seem like a porker...

Cheers, Paul

I think my CS was going about 80 in a proto maybe in the 1990's. I made a new head for it, like the Picco one with a Turbo plug, and it sounds nice now. Just need a paved circle, just doesn't seem possible to find other than going to Muncie. I would have to camp there, and bring my little Taig lathe maybe. Maybe that is the only choice, I want to make a B proto and/or an F2D speed to fly off the grass at home, It may work, I'll just pretend it is an A or B speed. 110 is pretty good for a 1/2A Proto, the Nat's there were quite a few doing in the mid 80 mph range. Yes the record holders have to do all the grunt work to get the nice times, test every prop, shim things test them all again, break a prop, ...

Hi Al,
The previous 1/2a Proto record at ~107-108 mph was held using a modified old C/S .049. The head mod alone was worth several thousand RPM gain. My Shuriken works really well with a Novarossi taperd seat turbo plug, & it's tough to blow one. One may need to try several heat ranges to get the very best one. I've since returned to using the Norvel Spiralite Speed plug which looks very much like the old Glo-Bee racing plug. Although a bit faster, it's one plug a run...

YES! The majority of 1/2A proto fliers are in the lower to mid 80's range. My Shurikens best (& only flight) last year was 97mph using the APC prop. My carbon props were 2 mph faster but both were broken in ground handling incidents.. :( Only 2 people ( from Napa ) flew over 100mph last year which is quite a hurdle to get past. I'm thinking that with better streamlining of my music wire L.G., better carbon prop ( pitch 3.8 - 4 "), best L.O. trim position, & some smoother pilotting, that the magic (for me) 100 mph is achievable. The last 10 mph will need a new model & further engine mods. Too much work at the moment however....

At the '99 Nats I placed 3rd at 105mph using a C.S. powered model of Chuck Schuette's. He gave me 17 DIFFERENT carbon & F/G props to test which I did. The Novarossi plug in that engine lasted a long time even though I was using 72% nitro fuel. The winner Greg Settle used 78% nitro & turbine oil in his C.S engine powered (38,350 rpm measured in air) carbon model for a near record 114 mph ( I think). Then they changed the fuel to the now used 10%. & speeds dropped ~ 10 mph. But ALL the sucessful C.S & G.Z. & Picco & Shuriken users have done (as you know) quite a lot of crank/bearing fitting & modification to get those extreme speeds. ANY model built to Sam Burke standards would be very competitive I think... All in all, very interesting playing with these bitty bore motors. Like you I have no test area or flying buddy to work on these things, so contests ARE my testing!

Cheers, Paul

Funny that you mention Sambo. I changed his MAAC # to mine on his plane. I would like to make another one soon if I find a flying site. That one has a landing issue. SCRAM? Society Combining Racing Airplanes and M. Former member. There was also SCRATA Society consisting of racing aircraft and that's all, I think Dave Kerr was the only member of that one.

Are you sure about that?
I thought these cranks would break as soon as you hit +20krpm?

I have two of those paperweights that I don't dare to run properly...

Mr. Cox,

YES, I am fairly sure about this (from all reports). Apparently it is not the high RPM running that strains the crank, rather it is hobbyists grinding on and more importantly the STARTING. Picco is too high a quality manufacturer of high performance engines to put out a crank that would not withstand running conditions. (They have world championship car engines) Fragile...perhaps, but fragile to tolerating flooded conditions while being mechanically spun over.
I recommend that you go ahead & run them. 30,000+ RPM is a unique sound to say the least! ENJOY!

Your Cox Venom however is an engine that WILL FAIL after less than a dozen runs without any abuse. But that is due to a flaw in the piston crown machining... (that's another story however).

Cheers, Paul

Hi Al,
Yes indeed! I flew with that SCRAM (& SCRATA) group on occassion. All great guys!
Cheers, Paul
p.s. Nice looking model there!

Okey thanks. :)

I've never owned any electric starter, so that's not a problem...

I was going to make some cranks, but then got one of those Foras and kind of forgot about the Picco. The Fora can't use an rc carb, so it is sitting for a while till I can fly faster?!! I believe the Picco was a fairly expensive engine, but they were selling them off cheap ($30) because of the weak crank. I think there isn't enough meat left because the hole is too big for the bearing size used. If you make a smaller hole on a new crank, it will go slower, so the trick is to either use a bigger bearing size, bore out the crankcase, make a sleeve for the crank, or make a new crank for a bigger bearing and bore the case..........

I've been looking at mine and getting itchy fingers-I'm aware of the crank issue-but is there an explanation in terms of it being a bit thin in the wall? (where exactly do they break?) or is it-as has occurred with some others-Holland Hornets, CS Olivers etc a case of less than optimal heat treatment which might be overcome-or at least improved-by some annealing, in the time honoured " several hours in the oven at about 600F followed by natural slow cooling therein..." approach?

ChrisM
'ffkiwi'

aspeed-you posted while I was writing this with at least half the answer.............

I think MJD said his Profi uses the crankshaft as the inner bearing surface, so that frees up space to design a stronger crank and still have a big air passage. the downside would be hardening the crank to act as a bearing surface..I do not know what the complications are with that.
My Ford 8.8 rear end uses the same idea. The entire axle isn't surface treated, just the area where the bearings ride.

I ONLY WISH I had the machining skill to make up new precision parts from my ideas! Keeping tolerances to .0002" or less (which is what's required) is mind boggling to me!

Galbreath is the main guy doing the Picco P0 stuff. It gets over $200, I think Toad tried some cranks too. I don't think the heat treating helped a whole lot. It was just a bit too thin, it would break in the port window, sometimes the prop would pull the front of the crank right out. I was going to use A2 steel, and press in a hardened crankpin. I have a Hardinge Chucker lathe, .0005" is repeatable in most cases, and .0002" is kind of doable if time is no object. I am more worried about indexing the port window in the crank than the shaft dia size. I think if the crank bore is smaller than the stock on, and a oval bellmouth is used, kind of like a turbo style crank, that something might work ok. The Fora .049/.06 does that on the crank.

I made mine out of A2, single piece. ground journal and pin after HT. 8mm dia requiring a new rear bearing and boring the case. I have not broke one of em yet. A lot of work. A2 or 8620 steel worked best for me. A2 being easier to heat treat.

I don't have a grinder any more, and it seemed like a lot of work to put in a new bearing, I just got a Fora instead, it is already the right displacement too. Not sure you can still get the cheap Picco any more either.

On crank breakage, I think the big thing is don't flood them and hit it with a starter, Really don't flood them at all.

As far as cost I got 2 engines at 19.99 each. Was going to do the machine work myself, but then found out about the crank failures.

I can make heads and prop drives but making a crank is well beyond my skill level and my little sherline would need a lot of stuff to do that.

Once When Doug had a solution crank I sent them to him. Had him do everything except de stroke it and the Nelson head, he turned the stock head down for less than $10. He will just do the crank and case boring if you like. His NVA's are really nice, since I was sending him the engine, I just bit the bullet and had him do it all.

The machine work was $150 in total, and great work.So for under $200 I have two killer engines. A little less $$ than a fora.

My Fora .049 was $150. The .15 is much more, I think $250. Your $200 for two motors is pretty good. I think I should have got the Profi .049 because the rear exh, and carb are more suited for what I had in mind, a piped rc with a throttle in case I get into trouble. The Picco is a little jewel though.

So far there has not been much evidence shown with build threads or with Youtube results to show what a great investment these engines are.
My idea of a good endorsement involves no less than 100 flights at full song.

So far I have found nothing in the small Profi engines I have to suggest they are not worth every dollar I paid for them. The combat .061 is no harder to start than a TD .049 and spun the living crap out of a fg combat prop on the first run and just keeps wailing away with little fuss. The proto speed .049 was also a piece of cake to handle on the first bench runs, although we were under fluorescent light in a shop so no tach readings. But it sure sounded snotty on a 4.2x4 and 10%. Never handled a Cyclon, I guess they might evoke much the same response.

I don't know if there are more than 50 or so of any of these motors around. There won't be reviews like say the Saito an OS threads where there are 1,000's of replies. Anyway, I also wonder about the car motors that can be converted, there is another couple of brands around. http://www.rcuniverse.com/forum/1-2-...ce-engine.html is an .06, and there is also an ACME .05 that may be useful too, as is the PIcco after a conversion. There doesn't seem to be any dealers that carry them other than the one in the thread, and he doesn't seem to reliably stock the .05. ( and the cool pipe seems to have gone up in price since the beginning of that thread.)

MJD, I want to hear about the Picco .05 engine with a speed or a pylon prop after it has consumed a gallon or more of fuel. So far there is a lot of confusing input saying that these engines won't break if they are treated right..

For me, well I got them because they were $20 and with a little of my time, I could have a fast engine for less that $50. Then the crank issues showed up, and I had written it off as $40 in paper weights.

When Doug found a way to make it better, I was happy, and willing to spend some money. We will see what the lifespan is.

Control line combat with expensive engines is stupid. They crash way too often, that is then only reason I don't have a fora, profi or cyclon. I have Profi and Fora F2d motors, but think 1/2a combat should be on the cheap.

I totally get the appeal of a low cost motor like this being convertible into a cool 1/2A - I think that's great. If my comment was misconstrued, all I meant was that I recognize I paid top dollar for the Profis I own, but that was by choice so I could enjoy ready-to-run top performance engines. I meant to get across that I am pleased with the value of them because I know they are solid and reliable, but yeah you don't get them for $50, that's for sure. I am panting to bench run the .15 now, I got my props, but the break-in prop is a reject.