Larry Driskill

I recently had the chance to test and work on an AME .061 that a fellow sent to me because it was a bit anemic.

What I think was wrong was that the shaft was binding a bit in the case. With a tornado 6X3 black it would turn 16,000ish for a moment or two and then get slower until it was down in the 14s. And the case would get hot. Classic symptoms of the shaft binding as the engine heated up. I put the shaft in the lathe and worked oiled 600 wet and dry paper against the center portion of the shaft. That takes some metal off, but usually not enough to measure with my calipers.

And I removed one head shim.

Back together it was turning the 6X3 17,000 to 17,500. I did not remove the venturi screen and could not see the carb barrel, but the barrel was traveling past wide open and slowing down if I moved the throttle arm full movement.

It was over 92 degrees here and the density altitude was above 6200 feet. Not ideal for making power. 30% nitro/ 20% castor/ remainder methanol. All running was done without the muffler.

The whole process took less than an hour, but left me thinking there is probably at least 10% more power hiding in the little engine.

Has anyone opened up the hole in the carb to a larger size?

Or removed the bolt that holds the carb on the case and sealed the bolt holes and attached the carb a less flow interrupting way? The bolt goes right through the middle of the action.

Opened up the muffler? Or better yet, made a larger one with a larger outlet.

Anyone have an AME .061 and also a Big Mig .061 and know just how the max. RPMs compare?

SGC

Larry,
Try trimming the 6X3" down to 5 3/8" , my bigmig 061 improved quite a bit both static and in the air. Best prop I have is a 6X3 1/2" master airscrew cut to 5 1/4".
Stewart

Andrew

The carb body venturi is probably sufficiently large (the restriction is the barrel hole) -- if you opened the hole in the barrel, it looks like it would pick up about an additional 10% or more of area. I don't think the carb bolt impacts airflow that much -- it's small and the throttle body is pretty large below the barrel.

My first inclination would be to open the barrel hole up to the size of the throttle body venturi and see what happens there -- however, it would probably require case pressure or a bladder tank to run consistantly. I used to run 6x3's mostly, but have backed off to 5.5x3 and am going to try the 5x3 rubber ducky's I got from KIT.

ptulmer

My Feedback: (5)

The 5x3 "rubber ducky" rules on an .061 Big Mig. If you could see the easy handlaunches of my 17oz delta and the 50+ top speed, you'd be pretty impressed with the combo. If speed is what you're after, try cutting down the MAS props with even more pitch. Like a 4.5x4.5.[X(]

btw, 5x3 on the BM .061 using 35% = 22k static

Larry Driskill

So, has anyone got a good read on what the AME .061 RC ought to turn a Grish, black, 6x3?

mikegordon10

I've removed the bolt that goes thru the venturi on all my Norvels. I tap the holes on both sides for a 4-40 bolt and cut off a 4-40 to the proper length to be just flush with the venturi sides. These are installed with blue locktite. I then polish the crank just as you described. I use a dremmel to flair out the opening at the mouth of the venturi but not the small end. I should mention that none of these are the RC version and are used in our on going 1/2 A Pylon event here in Utah. When I finish they are turning your cherry red props at around 26,500 to 27,500 static. The props are not clipped.
Oh by the way have you come up with any more of the yellow props? They don't turn up quite as well as the red ones but I think they pull our 13 oz racers faster.

fritzke

My Feedback: (1)

Andrew,
Are the "rubber duckys" you are refering to the Kavan Softprops from Hobby Lobby?
http://www.hobby-lobby.com/kavanprop.htm
Dave

Larry Driskill

Mike,

I may not be able to get any more yellow props. I have requested some new props (108mm diameter X 3 pitch) be made for you and yours ( that should be a tad more pitch).

ptulmer

My Feedback: (5)

Dave, the "rubber ducky" is the standard black cox 5x3. Very flexible and provide alot of thrust. Might be the wide blades, not sure.

Larry Driskill

Dave,

Don't you love it when someone writes in code instead of just saying "a black Cox 5X3" ?

Dan Rutherford ( always one to come up with a phrase ie. 'Plastic Nasty coined for foam CL Combat planes when folks first started using them' and Rubber Ducky for the flexible Cox 5X3) started that way back when the props and their molds were probably only about 25 years old.

Andrew

Hi Dave --

I may be referring to them incorrectly, but have always used the term -- these are the [link=https://ssl10.mysecureserver.com/kittingittogethercom/shop_details.asp?Category=Propellers]COX 5x3 nylon from KittingItTogether[/link]. I think the COX trade name is Double-Tuf. If the link breaks, try simply www.kittingittogether.com and search for propellors. They are flexible, unlike the glass filled MA's

dieFluggeister

Larry,
I'm quite interested in seeing what kind of performance can be squeezed out of the 061. Keep it up!

Not to divert the thread but last night I ran a practical test on the "rubber ducky" cox 5x3 vs the APC 5.7 x 3 Free Flight prop and found a marked increase in speed in the air AND static RPM with the APC. (Using an 049). I know others swear by the "ducky" but they just feel inefficient to me.

Ptulmer, Im impressed with the 22K static you got from the ducky tho. Hmmm...

ptulmer

My Feedback: (5)

To tell the truth, I wasn't. I get 16.6k from a black widow. Increase the engine 20% to an .061 and you'd expect a 20% increase in the RPM. (roughly) That would put you up to about 20k. Now change to front induction and a more effecient head/plug. 22k is about what I'd expect but not "more" than I expected.

Larry Driskill

I have been amazed at how much more power some of the .061s have over an .049.

With the Cyclon it "seems to be" more than the 20%, or 25%, difference in displacement.

Norvel had the .049 AME out long before the .061. One of the 1/2A CL Combat guys got a .061 from Norvel before they were announced. He never ran it in a contest, but test flew at a contest and let us think he was onto a cosmic new hop-up.

Same weight, same price . . . why not go with the bigger cubes, unless there is a rulebook problem?