Sig Akromaster

I've built 3 of them. This plane was my son's next step from learning on a Jr Ringmaster. The plane flies much better than the Jr did. It was designed for a light engine like a unmuffled Fox.15x. I used a Enya .15 which had the power, the weight was the penalty as it needed 3/4 oz. of tail weight. The wing would work far superior if you extend it it each direction 1 rib bay. Like most 15's, they fly fast. This doesn't like slower speeds. It will fly but the maneuverability is somewhat compromised. The nose between the back of the engine and the front of the leading edge is somewhat short as well. A medium wedge is in order here but you can be faced with fuel draw issues where the pickup is way outboard. The engine even if launched dead rich progressively leans throughout the run ending up in a screaming lean run usually resulted in going over lean.

The solution to that would be either finding the most narrow tank you could find. You could also cut out the doubler on the outboard side, sink your tank in between the beams and have it up against the inboard doubler which would place your tank almost 1/2" inboard. You could also mount a tank on the inboard side. Sweeping your gear forward is a must on this plane to prevent the flip over on landings. Ken

I have a couple of Akromasters. One is box stock with a Fox .15 slant plug for power, the other has extended wings and is powered by a Thunder Tiger .10.

I extended the wings by not trimming the LE and TE. This requires you to create extra ribs, more sheeting on the center section, and new wing flaps. I think the extra area is worth the effort.

Here are some pics showing the engines and the difference in wingspan.

George






If you use muffler pressure you do not have to worry about changes in settings as the fuel runs low. If you are not using a muffler, you might consider a uniflow tank. These tanks have a vent tube near the fuel pickup that provides a constant pressure whether the tank is full or near empty. Another choice is the chicken hopper tank.

My boys and I have had two Akromasters and my daughter and I are building two more. Of the first two, one was powered by an OS .15 LA with muffer a sullivan clunk tank and two inch wheels. And the other with a steel fin Fox .15 no muffler, two inch wheels and a wedge tank. We went with light two inch wheels becauce we were flying off the grass at that time. We built them completely stock and had zero trouble. No over leaning and no flipping over on the landings. They stunt great for a cheap kit and I highly reccomend them. I've read about lots of mods for this kit but most modelers I know say you don't get much for your effort. I've never had a sportsman .15, so I can't talk about that power issue.. Hope you enjoy it as much as we have.

Went and flew with the Central Arizona Control Line Club today and had the chance to fly an Akromaster. I was polite and didn't do any maneuvers but I got a feel for it and will definitely by building one.
Here's a photo of my Little Satan in the lineup:
https://i.imgur.com/BvsWT.jpg

Haha, it's tiny isn't it. I got a good laugh the other night when I showed up at my first club meeting with my show and tell Re-Bean, and set it in the shadows of everyone else's wings.

How'd they like your bladder fed reedy?
You made a pretty plane, JP. Did you fly a good exhibition for them?

When I first showed up one guy wanted to give me advice on how to start my engine. After he saw it fly he said I must be a technician because I can make a cox run great.
I added some side thrust and glued a penny on the tail to move the cg back like you suggested. I think I put on a good show and was able to fly the bladder dry due to the tight lines and tight loops. Since I didn't stick it in the ground I switched out the flexi black cox prop for a master airscrew cut down to 5x3 for my second flight. Holy crap that thing just ripped. It felt like I picked up 10mph and the plane turns on a dime now. I will try to get some video of it soon.
Oh yeah, I also ordered a akromaster today and left the field with plenty of contradictory advice on what engine to run and how to set it up.
I am going to try and run a sportsman .15 with bladder pressure on it.
Jim