forsakenrider

Which one of you will try the fuji 05 crank? I will send you an engine AND the fuji crank, you just have to fit it together. Requires a few thou off the step in front of the crank web and a new bushing pressed into the conrod. It has thicker walls then the picco so a smaller passage through it. It has a bit less stroke too, I'm wondering if this would bring it into true 1/2a and still run rather quick.

The only way to do it for a reasonable price I think is keeping as much as possible stock. Toads rear bearing is probably the ultimate solution but also the most work. If a Norvel crank can run resonably in the 28-30k then why cant a similar crank be made for the picco?

Toad

Smaller bore would make the crank stronger with a loss in power, I am not sure here, I never tried it. A pressed in pin...I don't know the advantage here unless you feel it is easier to produce.
Getting a ground pin pressed in straight without mushrooming the end or cracking the web sounds more difficult to me.
Have you tried these ideas?
I really like the engine, too bad the crank ruined it. too costly to correct for the masses.
Great for the engine builder building for themselves though.

Toad

The crank from the fuji is probably too hard to cut so you would have to send it out to a grinder. New bushing made for con rod....Have you measured the stroke and bore to see where the displacement will be? hate to see you chase this and not end up with a legal engine.
The norvel .074 crank has been done in these but not in a lower stroked version seeking the .049/.050 displacement
The original crank pin was ground smaller OFF Center to get the smaller stroke. the dia of the pin has nothing to do with the stroke. it is the center of its location.
Do some simple math, figure out what stroke is needed then set the pin offset. maybe the fuji pin will have enough material on it to grind it to a new center.
I hope your grinder doesn't charge you a lot.

AndyW

My Feedback: (1)

My Picco/Brodak uses the piston, liner, rod and crank from the Picco, no bearings. I used the weak, Picco crank because it was a drop in fit. You say the Fuji is also a drop in with the bore smaller making it a stronger crank? Sounds perfect, I'll get ahold of Uh,,, it escapes me right now, who offers the Fuji? All I have to do is substitute the Fuji crank and go for the gold. Neat,, thanks.

But wait, is all we need is a rear bearing? There may be room in the Brodak case, MK1 or MK2,,, need to dig all that stuff up.

AndyW

My Feedback: (1)

A brass bushing at the front end that's a tad shorter will eliminate the need to grind away at the crank. Add a rear bearing and we may just have some serious potential.

IF the Fuji just happens to have a shorter stroke, that would make this all that much easier. How do we find out?

ffkiwi

The main reason people use pressed in crankpins is two fold-it simplifies production by doing away with the need for eccentric turning and grinding, and secondly it is normal practice (for those who DO use this production method) to use a needle roller or roller bearing roller (depending on the required size) as the pin-which are not only available in a variety of sizes and lengths-both metric and imperial, but also very hard and ground to very close tolerances. Not to mention produced in huge quantities-so the unit cost per needle roller is miniscule. The only production engineering issues are then drilling and reaming the hole for the pin at exactly 90 degrees......and allowing the appropriate interference fit dimensions. Both PAW and K&B use pressed in pins in at least some of their engines. Rollers are very hard-so mushrooming is not an issue-and it is possible to buy 'over and under reamer sets 0.001" smaller and larger than a nominal size quite cheaply-Micromark lists one such set quite cheaply at less than $100 for 7 imperial sizes-see Micromark cat #84753

ChrisM
'ffkiwi'

AndyW

My Feedback: (1)

As I poke around looking for a Toki/Fuji crank, (Mecoa) I came across this. http://profi-me.narod.ru/photoalbum1kub.html Pretty snazy, looks light, looks fast. I get it now, the angled exhaust clears the wing when side mounted. And they wisely oriented the carb and needle in the UP position.

Has EVERYTHING already been invented?

Still, it'll be fun to try to get good numbers as a combat engine that can also be used as a throttled, RC engine. Double duty, bigger market.

AndyW

My Feedback: (1)

It gets better. Here, http://www.microsofttranslator.com/b...album1kub.html the translated version, tells us that it's avasilable as an .049 and an .06,,,,

They claim that it twists like a Cyclone. But does it have ball bearings? If so, it's in a dang neat package. Can we say wow factor?

forsakenrider

I have two of the 06's andy! they are very nice! and recently release a rear exhaust regularly placed intake version which MJD has bought. Check his blink thread or a thread I recently made. I even have a no nitro youtube video...
https://www.youtube.com/watch?v=EOWO...i8duQ&index=10

combatpigg

My Feedback: (3)

Make a close fitting bushing that has a slit in it to hold the Cox piston in a chuck...
Take a wire and tie off the rod so it doesn't flop around.
Just use a Xacto blade freehand to shave that Leadloy piston. You need good light to see how you're doing. The back side of the blade takes wafer thin shavings with just medium hand pressure.
It's really a fun little "operation" to perform. While yer at it, shorten the skirt to obtain any SPI that you are looking for.
The pistons that were made in the later years don't hold a reset as long as the early models so if you know anything about heat treating the Leadloy piston that might help.

aspeed

Profi's are pretty cool. For RC, you could likely fit a carb off of something if that is what you need. The throttle may be more of a shutoff than a throttle, but you never know. Still no muffler for my field on the Profi. They are not really that bad of a deal if you have to pay for someone to make parts for a Picco. (For a) I have heard of problems getting stuff from MECOA. Maybe a hard move, getting old, not making any more new parts any more, vey little stock.I am not trying to slander MECOA, just things I have heard.Mr. Toad-If a crank pin is pressed in, then maybe the crank doesn't need to be hardened too? I have pressed one in on a Picco .67, boat motor, but never tested it, just sold it for parts. Maybe overall the Picco crank is ok, and the revs just have to be kept under say 25,000 rpm? Just thinking out loud here. edit- that is a record three people snuck in while Iwas typing. I have to type faster.

combatpigg

My Feedback: (3)

No self respecting 1/2A Combat flyer will act like a little girl and send you home if you show up with a .051. This is one category of AMA competition where common sense and sportsmanship is the rule of the day.
Speed is a different story, they must be "sticklers" for exact details.
Unless you can build a Picco that will do over 150 mph on lines....I wouldn't worry about destroking it to make it legal for that market. To run this number you're looking at 40,000 rpm on a very crafty [and light weight] G&Z pipe.

aspeed

Like the one on the bottom of the picture?

combatpigg

My Feedback: (3)

That's the engine that I bought from Bill Hughes about 8 or 9 years ago.
I revisited my records and it looks like I paid $100 for it.
It was the same engine he placed 3rd at...at a FAI event in Germany IIRC.
I built this plane for it.......
I spent an additional $300 to keep the engine running over the course of a couple years before pulling the plug on that sucker.
Back then I didn't clock it, but it had to be doing every bit of 150 mph.
There might still be a video in RCU's archives titled something like "NW 1/2A Pylon Racing" that was posted by Scudrunner, but I've struck out trying to find it.
I can't find a photo of the plane with the cowl on, either. It was no Beauty Queen, but it was about as streamlined as I could imagine.
It flew with HS-55 servos and a cheap park flyer RX.

SGC

A good site for 1/2A motor comparisons , even though its aimed at FF , http://www.gregorie.org/freeflight/f1j/index.html

aspeed

CP, that is an engineering feat getting all the radio equipment in cleanly, and a tank too.

DeviousDave

I may be able to grind the step if the crank is long enough to put in the v-block of an offset whirly..

AndyW

My Feedback: (1)

Thanks for the link. Lots of good info and sources for the bits and pieces for experimentation. All of which has inspired me to make the Norvel .074 into a ball bearinged device. The intent is to determine how much ball bearings contribute at the speeds that RC and bigger props run at. I suspect that the real value will show in diesel with its inherent higher compression and loads on the crank. At first, just the back end wll get a bearing and then the front end. It may be that a bearing at the rear is all you need, ala Mills engines. Shoot, for a few bucks more NV could do this at the factory.

And I see that the Profi uses a 10 mm crank [X(] and does have ball bearings. A big bore in the crank seems to be a must for high speed.

The Brodak MK2 has a bigger crank and it'll be simple to bore out the Picco/Brodak hybrid. Neat, that means I can run this one as a diesel with confidence.

Again, thanks for the link.

DeviousDave

The bearings will pay dividends at high rpm because drag goes up to the square of RPM.... On something like a .40FP compared to a .40FX the difference is more in port timing-looke at the Norvel .25 big mig vs. the AME .25..... 500rpm different!

combatpigg

My Feedback: (3)

Running it on bladder made placement of the "tank" easier than if the tank was made out of tin but the latex bladders use to pop a lot due to the high frequency vibes. They would also corkscrew themselves off which happened more times than what you could call just bad luck. What helped was to carpet the fuel cell chamber with velcro.
A bladder can't "ramp up" to fuel demand so you really need to anticipate [guess at] the inflight needle setting or else roast a lot of parts. I think this is why having a sheetmetal tank that is pumped up with exhaust pressure is a better way to go. I'm talking about running a high timed [180-190 degrees of exhaust] on a pipe. The first G&Z I got from Bill would still be 4 cycling at 30,000 rpm and gain a full 10,000 when it hit resonance. Once that engine got roasted, none of the later combos I put together ran nearly as strong as the original one that he put together, hmmmmmm.......[8D]

aspeed

Bill knows his stuff.

AndyW

My Feedback: (1)

The future is here, guys. http://www.youtube.com/watch?v=zApmGFDA6ow I hope to see the day you can buy one of these as easily being able to afford a laptop or Iphone.

Grow your own engine from scratch. Imagine, a titanium crankshaft. Yeah.

AndyW

My Feedback: (1)

And if you need that special, odd size, ball bearing,,,,,,,,, http://www.youtube.com/watch?NR=1&v=...ture=endscreen

combatpigg

My Feedback: (3)

Andy, I've read about that capability and it will accelerate Homo Sapiens progress and abilities to create things through trial and error. Things that would have been considered economically stupid to consider.
No matter how smart we think we may be, "trial and error" will always be right up there with accidental discovery and of course divine intervention for how progress is made....
Imagine being able to design, build and test run a little engine all in the same day...?
If you don't like it, just melt it down and start over the next day.

AndyW

My Feedback: (1)

Agree.

That reminds me of some guy named Nobel a few years ago. He spilled some chemicals and fearing the wrath of his wife, he hung the rags up to dry over the stove. Next thing he knew, BANG, the world changed forever, for good AND bad. What if his wife wasn't so cranky?

Then again, according to some new archeological findings, the Sumerians had this technology and more.

At the turn of the 20th century, some notable scientist declared that the patent office should be closed as everything that could be invented already had. Good thing that they didn't, otherwise a certain patent clerk might never had made enough of a living to dabble in math,,,, and then there was Tesla.

Me, I'd like to clone a Norvel .049 into an .010 size and make it a diesel. Alternately, blow up the original, VA MK1 into a .45,,, just to see. AND, clone the TD .049 as an ABC engine,,,,, DANG, I wish I was 18 again.

BTW, I really like your quote from Mr. Orwell. He was an insider who tried to warn us.