Somebody posted a picture of a nicely-done Super Whipsaw.  This got me thinking of building one because it was my first beyond-1/2A model.  Mine didn't go well because of my inexperience.  I'm thinking about taking another poke, so I downloaded the plan from Outer.

Looking at the plan shows me some of the problems of the kit. Using the wrong size LE & TE and no proper way to place the fuel tank.  If I proceed with this the outside will look right, but their will be considerable re-engineering inside the wing.

One lesson-learned was that kit designers are NOT all-knowing geniuses' and don't be shy about making improvements.

How about a bladder in the wing?

For the tank, I will beef up the center section enough to where I can cut the sheeting and have a hard tank in the proper location.  While I use bladder tanks on combat planes, this is a sport model and I want the causalness of suction.

For the wing I will use my usual setup of a smooth rib section with square-on-edge LE and two 1/16" TE pieces, and capstrips to smooth it out.  This always works for me regardless of the design.

             Paul, I had built two of them and one of them was a Pat King model. My friend sent Pat the plans and he made 3 versions , a .46 sized , the Super and a 1/2A version. My Ambroid version was certainly built heavier. My tank was notched into the leading edge. Mine is powered with a Fox .15 BB I received from Larry Scarinzi. Larry had drilled through the center of the mounting lug into the crankcase to provide crank pressure. It works terrific actually and it turns up pretty good. I also received a chrome plated cylinder from him for this engine. To date, the iron/steel is doing terrific. I experience a bit of a problem with this plane which I can't seem to nail down. I launch it, it flies well right out of the launchers hand. The problem is when I decide to get heavy handed and begin to hammer the controls hard. the plane in hard inside maneuvers goes into the maneuver fine and then it's like it comes if it's rails and it flies across the circle almost free flighting. If I do the maneuvers less aggressively, it does it with no issues. Wingtips are correct, no warps, it's just when I try and really snap the plane into a maneuver is when it goes crazy. I really think the wings are flexing and as it does so, they're twisting. I'm not certain as to why this is, I would love to correct it. I have a much larger one for a LA .46 that Pat did as well. I just haven't built it because of this.

Quote from: kenneth cook on March 14, 2026, 01:33:28 PMPaul, I had built two of them and one of them was a Pat King model. My friend sent Pat the plans and he made 3 versions , a .46 sized , the Super and a 1/2A version. My Ambroid version was certainly built heavier. My tank was notched into the leading edge. Mine is powered with a Fox .15 BB I received from Larry Scarinzi. Larry had drilled through the center of the mounting lug into the crankcase to provide crank pressure. It works terrific actually and it turns up pretty good. I also received a chrome plated cylinder from him for this engine. To date, the iron/steel is doing terrific. I experience a bit of a problem with this plane which I can't seem to nail down. I launch it, it flies well right out of the launchers hand. The problem is when I decide to get heavy handed and begin to hammer the controls hard. the plane in hard inside maneuvers goes into the maneuver fine and then it's like it comes if it's rails and it flies across the circle almost free flighting. If I do the maneuvers less aggressively, it does it with no issues. Wingtips are correct, no warps, it's just when I try and really snap the plane into a maneuver is when it goes crazy. I really think the wings are flexing and as it does so, they're twisting. I'm not certain as to why this is, I would love to correct it. I have a much larger one for a LA .46 that Pat did as well. I just haven't built it because of this.

I have built both the Whipsaw and the Super Whipsaw when I was a youngster.  Actually due to the low-mounted wing they turn fine inside but lousy outside.  As far as what you are talking about-the airplane looking for greener pastures on it's own-it is likely one of the following:
1.  The stab is crooked in relation to the wing,  looking directly from the front of the airplane.  My guess would be inside side of the stab is high.  2.  The other possibility is the design itself.  They have long narrow wings and thin airfoil.   It could be when you maneuver hard and really slow the airplane down engine torque takes over and twists the airplane inward a little which lessens line tension enough to flatten the controls and send it sort of free flighting....There wouldn't really be much of a cure for it.  It really is a design flaw.  Maybe more engine offset will help a bit.

Dave

About the tank placement.  I don't remember about the smaller one but on the Super I installed a metal tank in the wing BEHIND the leading edge.  I wouldn't cut into the leading edge because there isn't much other structure to the wing there.   I built mine to use in slow combat at the time. (roughly 1970ish)  I think it had a green head Torp .35 on it.   For sport flying a good .19 to .25 would be more than adequate.   A cute little airplane but don't expect too much from it.

My first & only Whipsaw thus far was a Super with an Olpmpic 15.  I didn't get it going well enough to judge the performance.

My next effort was the "Big Jem", which was a double-size Little Gem.  The Little Gem was an .020 design published in a magazine.  Both the Little & Big Gems went good for me.

I have an new Olynpic 15 and thus far the Super Whipsaw looks like my best bet for an airframe.  But first, I need to bench run the Olympic before diving into a project.

I was very happy to receive the Olympic as a birthday present, but it was almost istantly superceded by the TeeDee 15, which was easier to mount and run.

Quote from: Paul Smith on March 15, 2026, 01:22:28 PMMy first & only Whipsaw thus far was a Super with an Olpmpic 15.  I didn't get it going well enough to judge the performance.

My next effort was the "Big Jem", which was a double-size Little Gem.  The Little Gem was an .020 design published in a magazine.  Both the Little & Big Gems went good for me.

I have an new Olynpic 15 and thus far the Super Whipsaw looks like my best bet for an airframe.  But first, I need to bench run the Olympic before diving into a project.

I was very happy to receive the Olympic as a birthday present, but it was almost istantly superceded by the TeeDee 15, which was easier to mount and run.

I have or have had just about every engine made in the last 70 years. I routinely fly with the RO Jett .76 which is fully capable of removing any body part you are unfortunate enough to put in front of it.  The Olympic .15 is the only engine that I still am afraid of.  It comes around so much faster than anything I've handled and will not even allow you to get a chicken stick out of the way fast enough.  It is enough to pull your Super Whipsaw but I really suggest you use an electric starter on it for safety....It is also quite loud.

Dave

Yeah, the spring starter was a problem, too.  With a Cox .049, we regularly attached the glow clip and wound the starter.  With the Olympic, it would fire powerfully while you were winding the spring.  You needed to get a helper to attact the wire while you were holding the prop.