In 1975, my son Guy, built this model -using a .19 Torp engine - Today, i wiped it off - and put in a Hacker 20-20
it now weighs 20 ounces ready to fly. All up weight is much less than original setup which required a big chunk of lead under the tail
The Hacker 20-20 pulls 16 oz in a 3D foamy model -extremely well
Ithink it will do well in this setup

The SIG Akro's fly really well. Where's the wing flap sections? You're robbing yourself of a little extra wing area.
My Akro has an OS.15FP and weighs 20oz. with muffler, needed 0.6oz. on the tail to balance.
Terrific fun to fly.

Flaps? - I guess they were lost in the shuffle 35 years ago

Yeah, they come in the kit, can be glued to the T/E and fuse. or made moveable.
When's the test flight?

When winter winds n snows go away - we will fly -

Is your battery 2 or 3 cell.. Can't quite see... What controller/timer have got tucked under there. BTW the flaps are 1.25 inches at the root and 1/2 inch at the tips.
By all accounts she flies plenty well without them operating, just glued on.
Another thoroughbred from the golden age of U/C.

The Akromaster flies just fine with the flaps fixed/glued to wing/fuse. Even with the flaps stationary she'll do loops in a roughly 10' circle. Of course, the elevator has nearly 90-degree movement in both directions, but that's how I set-up a fair number of my CL planes - lotsa elevator - with or without flaps. Been flying mine now for about 8 years with a 30-yr old Fox-.19 - - love it!

Dave

Dave W. Do you find that you can stall your stab and elevator? In one of the Frank Zaic books he figures that you can stall the tail with too much control and actually make loops bigger. I did some experimenting and found this to be the case. I gave more control, well beyond normal, and the loops got much bigger. I now set my elevator throws 20-25 degrees either way. This is enough for square corners. There was some discussion of this on another forum and video evidence showed that deflection of flap and elevator in turns is in that range, or less.

In my experience, too much flap deflection (more than 15 degrees) has the opposite effect for which it was intended, actually adversely affecting the lift component of the wing and causing a nose down pitching moment.
The 90 degrees elevator travel mentioned would surely act much more effectively as a speed break rather than an AOA influence. I use about about 25 degrees as Jim does.

Jim & BtnFlyGuy - you're both 100% absotively, posilutely correct in all you say - which is the prime reason I set the Akromaster and my latest Skylark up as they are - the Akro with near 90-degree elevator, and the Skylark with 1/2 as much flap deflection as elevator deflection.

Now - you're both wondering if I've completely gone off my rocker - knowing the effect it would have and doing it anyway, so I think a word of explanation might be in order. But even before that, remember that I'm a sport-flier, not a contest flier. That means I like to play with my planes and have fun - I'm not all that worried about how perfect the maneuvers are.

In the case of the Akromaster; just because it has the capability doesn't mean I use it very much. I've been building and flying CL planes of all sizes (.049 "Lil Satan all the way to Fox.45RC-powered Shark-45) since Christmas 1955 (Cox .049 PT-19 as a Christmas present - I still fly that plane occasionally, just for giggles), so I pretty much know what they can and can't do. One thing I found in the 1970's was a fabulous little plane called the Cosmic Wind which, I think, was put out by Midwest. With the very same Fox .19 engine and elevator set-up (no flap capability in the design) I could put the CW on her back - give her full-bottom elevator and bring her to a complete halt (the elevator not only turning the plane, but acting as an airbrake at the same time) in the sky as she came around upright again. This was usually done at the top of a fairly low loop. From that point, I could play with the elevator and bring the nose back vertical - thus hovering a CL plane at full power, about 30' off the ground.

Yeah, 3D-type maneuvers with an aerobatic-type CL plane. It's pretty awesome.

Anyway, the power/weight of the CW was such that she'd start settling after a couple seconds and actually hover down toward the ground. At about 4' I'd give her a bit of bottom-elevator and bring her back out of it in normal flying attitude to continue with the flight. It was huge fun!!!!!!

When I built the Akromaster I was seeking the same capability but, as it turned out, the Akro is simply too light and she'll climb right out of that loop-top and continue with a wing-over. I built a SMALL weight box into her right over the main-spar, playing with adding weight to bring her up to the point that she'd hover, but that hasn't worked too well either. I probably need to replace either the Fox-.19 with a .15 or the 8x6 prop with a 8x5 or 8x4, in addition to the added weight. Or, it could be that the Akromaster simply doesn't have that barn-door of a wing that the Cosmic Wind had (pic of the CW and my Midwest P-63 below), so the drag needed to slow her down enough at the point of rotation simply isn't there.

Now, the Skylark; You're right with too much flap having negative effects, especially with take-offs. I've built/flown 7 different Skylarks, including a twin-engine version that I cooked up, and all have had the same tendency to nose over on take-off if I didn't fly it 100% correctly off the ground. Long ago we came to the conclusion that there simply wasn't enough elevator on that bird to compensate for the flaps on T/O. So, I got into the habit of setting the flaps to 1/2 elevator as I built the planes and all my planes with flaps & elevator have been set-up that way ever since.

There's good and bad to everything, right? The good is that they don't nose-over, the bad is that they don't like maneuvers like vertical-eights, hour-glasses, things like that. The most impressive good, from the spectator's point of view, is that they become big, VERY GRACEFUL birds in the air. Once again, I'm a sport pilot, so my main aim is having fun and watching a big beautiful bird BE a big beautiful bird, not necessarily doing perfect aerobatic patterns.

Geez, guys, I'm writing a book here.

One final point I'd like to put to all y'all concerns that other plane in the pic with the Cosmic Wind - the P-63. She flew in Alaska mainly, which is neither here nor there, but the color scheme came to be as it was because most of the P-63's that were built were given to the Russians during WW2 and they flew them as tank-busters (which is also neither here nor there to the point). The model was a fabulous flier, once I'd added enough weight to the tail to balance her. My #1 all-time favorite maneuver with this particular plane came about one evening as I was "showing off" to fellow club fliers - yeah, I was once young and stupid too - and I tried putting her on the ground at full-power.

It worked!!!!!!!!!!!!

Seems I'd built it with the nose-wheel just barely high enough that the nose actually pointed just the tiniest bit down while she was on the ground and when I touched down under power I could add a bit of bottom-elevator (which also gave me top-flap) and keep her there for a lap or 2 with that ol' Fox-.35 beating strong and loud (this was before the days of mufflers being required). This plane was set-up with equal flaps/elevator but that was to her benefit as, being tricycle gear, there was no worries about nosing-over. Once I figured I'd burned enough rubber off the tires on the asphalt I'd give her a bit top-elevator and she'd come screaming off the ground, going into an immediate wing-over - I'd usually go inverted at the bottom of the wing-over just for the fun of it.

Anyway, tricks like these are a lot of what I fly for - simply to see what different kinds of FUN I can have while I'm getting high on the smell of castor oil on a warm and sunny afternoon.

And that, gentlemen, is the prime reason we all fly - TO HAVE FUN!

Dave

Dave, Regarding your 3D flying experience, I too have done this by accident and was later able to recreate the thing by choice! It is an amazing feeling for sure but I learned I was far behind Jim Walker and his 3D flying. You should see him do his famous "Sabre dance".
Here is a short example of this 3D work with one of his planes.
http://www.youtube.com/watch?v=09sFpHlHkoc

Also found here: http://www.americanjuniorclassics.co...sabredance.htm

Robert

Yup!! That's the thing!!!!!!

Ye gads, I've never seen the Walker video before. That's great stuff, and I was only 1 year old when he was doing it.

Looks to me like he was using a throttle with a 3rd line in the video. Hmmmmmm, maybe that's the way to go. I still have some of my old 3-line throttle cranks, might just fit one into another Akromaster and try that idea out.

Yeah, good stuff!!

Dave