1fishnfool

My Feedback: (42)

I just got back from the C/L World champs in Spain,and I picked up a Fora .020.It looks pretty cool.It weighs 21 grams with no plug in it.It is designed for a cox .020 plug.This one is brand new,but I don`t really want to run it yet.Sorry for the bad pic.

Tim Wiltse-RCU

Holy crap...that is the first I have seen that[X(][X(][X(][X(][X(][X(] What did it cost you if you don't mind me asking?

Later,
Tim

Sneasle

tiny little buggar, ain't it.

Clean

Oh great, a brand new engine designed for a non-existant plug?

What other options do you have for that cute little engine that without a plug is gonna windmill excessivly after the handlaunch.

skaliwag

My Feedback: (1)

Who had them for sale?
Did they tell you any thing about it.... What will it spin at? What's the metalurgy inside?
How much was it?
Any idea if they will be world wide distributed?
More info... Mucho mass infrmation for favor...

Larry Driskill

In 2004 and 2005 I worked with those Fora folks to get the F-.020 made.

So far I have not had one that made the power of a good TeeDee .020 and so I have a bin of them. . . but didn't try to market them.

I have several versions - AAC, a sorta ABC, Nelson plug versions, Cox plug versions, most have three intake ports and one exhaust, but I have a couple of copies of a two exhaust version.

Japanman has done some extensive and clever work on a couple and had them turning nicely, but off the shelf they have been a disappointment.

Larry Driskill

More .020 shots -

Tim Wiltse-RCU

Larry,

Are you holding out on us? Those look plenty neat. Is it something that the Fora folks still make or something and just don't sell here. Any way for a guy to get his hands on one just to mess with?

Later,
Tim

MJD

My Feedback: (1)

First time I've seen that method of cylinder attachment. Interesting little motors. Talk about a labour of love - designing, building and marketing a high performance .020!

MJD

Larry Driskill

Not intending on holding out, just holding back. While I was always confident that the VAs I shipped were going perform well, I gained no such confidence running these.

Tim Wiltse-RCU

MJD,

It's really no different than Norvels method. Plus lots of older Ignition style engines were made like that.

Later,
Tim

ptulmer

My Feedback: (5)

I had to twist his arm pretty bad to get a couple. I was using them in place of Peewees. They turn about the same and weigh more. I haven't flown one yet. But will soon! I'd like to see Japman's results or see what Tim could do with one. The quality is there, just no power whatsoever.

combatpigg

My Feedback: (3)

Start from the crankshaft fit [with 1000 grit or Bon Ami and oil], making sure that a prop flip spins just the crank for a few seconds. Hyper cleanse all lapped parts. The prop should flip smartly and toggle after flipping the assembled engine. At this point, you have done your home work and it is time to break it in. I would say that the same rules apply to bigger AAC engines, under prop it for the break in and let it scream richly. Once a needle setting takes hold and the exhaust residue is clear, then the rest of the job is finding the best prop to run. Probably will have to think small and thin if you want this engine to run like its' bigger brothers. I'm just making talk here, [I've never seen this engine] but I would think that the right prop is the key, and lots of nitro.

ptulmer

My Feedback: (5)

Or what CP could do with one... I haven't taken one apart, but now I'm wondering if the piston could be lightened, etc. Right now, I'm running the Peewee prop, but you may be right. A prop change could result in more thrust.

Japanman

Well, interesting to see that fora are trying to sell these things directly.
Fishnfool you may be in for a few dissapointments I am afraid.
The construction is good, but the cylinder design isn`t.

Larry sent me a couple of these to work with after getting a few more prototypes than he bargined for.
The idea was to try to get one to run as well or better than a TD020 and then get the guys at Fora to make them that way.
After a lot of time trying various mods I found a couple of simple things that make the engine go well enough to fly a plane.
I am sure you guys will improve on my numbers via the accumulated knowledge of the 'black arts'

CP, forget that it is made by fora. the engine as it is is severely restricted in the cylinder port design and will not scream what ever prop you put on it. <I have tried[8D]>

Maybe it is easiest if I post the mods I did so you guys have a good starting point.

But first let me just say I will do this on the condition that interested guys get your engines off Larry, not Fora directly. Larry invested a lot of his time, and more importantly money to try to bring us a good 020. I am sure we all know that it was not going to be a serious commercial project.
In then end he was let down by the engine makers who did not want to change the design of the prototype, even when it would considerably improve the engines performance, which sort of made their opperation seem a little fishy.

The engines run with a Nelson plug, but run the best with a cox 020 plug.
I am a bit reluctant to write numbers here, as modifieing these things is a serous work of precision. you have to get thigs dead right for it to work and it only takes a slight lapse of concentration or a beer beforehand to turn it into junk.
When I was doing it I would periodically pick up an 049 and it would always look huge!

With my modified cylinder and cox plug with 25% nitro it was possible to get 22K with an apc 4.2x2 with some effort and my best engine would sit on 24.4k with the same prop and fuel.
I have a highly modified engine that runs 30K with a 3.6x2 home made carbon prop and 33k with a pipe.

Stefan

ptulmer

My Feedback: (5)

I'll agree to pick mine up direct from Larry. Spill, dude!

combatpigg

My Feedback: (3)

Maybe high expectations don't scale down well below .049? The engineers that design large engines make the parts marginally strong for a good reason, marginally strong parts not only are cheaper to produce, but take away less horsepower to turn. The trick is to make everything just big and heavy enough to do the job. The bigger around your crank and rod journals are, the greater the frictional losses. Maybe this .020 engine needs a smaller main shaft and crank pin, just for starters? Slight differences in size will add up to big differences in rotational and reciprocating speeds. It sounds like FORA is a good machine shop, and copyier of the CYCLON, but not into engine design?

Japanman

In many ways the engine`s crankshaft design is very similar to the TD020 in pin and shaft diameters, and as such you would expect it to be not too far off the money. at least when in the TD`s performance curve.
Then again it is a new engine and unfamiliar size to try modifications in. Any mods are going to be interesting.

Stefan

combatpigg

My Feedback: (3)

I don't have the friction chart of metals in front of me, but I would think that the smaller you go, the more you need to pay attention to that detail. There is something amusing about a 40 year old engine that can still claim to be top dog, spinning piston and all .

Japanman

Pigg, As stock these engines would get blown away by a pee wee, but with a few modifications they perform at least as well as a TD020, if not significantly better.
Add to this the AAC construction and you have one good little engine. During testing I murdered the little suckers, overlean, overheated lots of times. I often wondered just how many cox cylinders I would have worn out duing the same period.

Stefan

bsindel

Jman,

Would you post the mod's you made to this engine, with a description of how
that mod improves the performance. I would seem that such information
could be applied to other small engines as well.

Call me curious,
Bill S. (the other Bill)

D Bronk

.I would like to know Too,Please..

combatpigg

My Feedback: (3)

Well, we're not comparing apples to apples. If you wanted to devote 20 hours of research and hand work to a .020TD, you might find some more power lurking there as well. I think that if the FORA .020 mods can be carried out within an hour, there would still be some folks interested in paying a little extra for an engine that puts out.

Cox had some very sophisticated bore finish testing equipment, if I remember correctly the tester sent a blast of air through the cylinder and the air currents that exited were somehow evaluated. It was some kind of GO - NO GO check point in the build process.

Japanman

You are right in that we`re not comparing apples with apples.
The F engine is really only a go`er with mods but reason I chimed up about it is I thought a bunch of you guys mught be interested in doing the mods yourself to get a cool AAc 020.

Stefan

D Bronk

So,I suppose I`m on My own, when My engines arrive.Should be a Fun Challenge, to try and Get 33,00 RPM..I`ll share my Results, as I go..