Author Topic: Sig Akromaster Build (Read 14839 times)

Allen Eshleman · « **on:** March 03, 2011, 03:46:00 PM »

I just ordered an Akromaster today from SSHobbies.

I will be using a McCoy 19

Questions about the build.

Could I install flaps and would it help it to stunt better.

If I thickened the wing in the center longwise to increase the _________. I forgot what you call the thicker wing - would it help it to be more stunt worthy.

Could it possibly do the pattern or most of it?

Thanks in advance.

Bill Little · « **Reply #1 on:** March 03, 2011, 03:56:49 PM »

HI Allen,

I have seen Tommy Luper fly as pretty good pattern with a Sig Akromaster. It even was powered by an old ringed McCoy .19. However the LG was left off since it was still sorta nose heavy with the .19 up front.

As far as stunting, nothing really needs to be done as far as all the mods you describe. IMHO, you are entering the realm of diminishing returns with all that. Save those ideas for a bigger stunt plane that will be capable of more performance.

I would, however, make the wingspan greater. Jut don't cut off the ends of the LE and TE material and make a couple extra ribs. Many people have posted that mod to the kit and it works well.

Of course, a Sig Akromaster is only going to be "so good" of a stunt plane..... but it will be fine if you aren't planning on trying to win Expert at a local meet, or enter Open at the Nats!

(it's really a fun little plane to fly)

Big Bear

Allen Eshleman · « **Reply #2 on:** March 03, 2011, 04:33:42 PM »

What about shortening the nose area?

I would like it to have wheels. I'm not aiming for EXPert. I've just started to do vertical 8's.

I think I may lengthen the wing as recommended.

I'm wondering what prop(s) to use with the McCoy. I have some 9/6's APC and a 9/5 APC.
I've used the 9/6 with a McCoy 19 on another plane with fairly good results. One problem with one of my engines is that it just runs rather fast. Not much 2-4. Maybe I need to check the spray bar placement.

Bill Little · « **Reply #3 on:** March 03, 2011, 04:43:57 PM »

Quote from: Allen Eshleman on March 03, 2011, 04:33:42 PM

What about shortening the nose area?

I would like it to have wheels. I'm not aiming for EXPert. I've just started to do vertical 8's.

I think I may lengthen the wing as recommended.

I'm wondering what prop(s) to use with the McCoy. I have some 9/6's APC and a 9/5 APC.
I've used the 9/6 with a McCoy 19 on another plane with fairly good results. One problem with one of my engines is that it just runs rather fast. Not much 2-4. Maybe I need to check the spray bar placement.

Hi Allen,

I ahve never used an APC on the McCoy .19, but do use (-5 props, even 4 1/2 or so (which a wood "9-5" can be sometimes!) Just make sure you are using PLENTY of oil in the McCoy (I'm sure you know that). 10% nitro is as high as I go with them, and no less than 25% castor oil. I have used one for years in a Fierce Arrow "400", and I still have my first one, it was my first "big" engine! LOL!!

Big Bear

Russell Shaffer · « **Reply #4 on:** March 03, 2011, 05:45:37 PM »

I have had a couple of Akromasters with 19's and I agree with the wingspan increase. Just don't cut the spars and leading and trailing edges when the instructions tell you to. Set the engine back as far as you possibly can, it will turn out somewhat nose heavy. I would also forget about the rubber band landing gear attachment. Put the gear right where SIG says, but use the bent nylon clips that Dubro and Great Planes sell. The rubber bands let the gear swing back and poke holes in the wing. It's easier to bend the wire gear back than fix wings. It's a fun little airplane that flies very well. My latest was doing 4 second laps with an old SuperTigre 15 that probably weighs as much as your 19, so I went to 60 footers. But do start with something in the 50 foot range. Have fun.

jim gilmore · « **Reply #5 on:** March 03, 2011, 06:06:25 PM »

My akromaster that is almost finished and sitting in CA has an ap .09 on it. Hope to try it in Aug.

Rusty · « **Reply #6 on:** March 03, 2011, 06:19:31 PM »

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Randy Ryan · « **Reply #7 on:** March 03, 2011, 06:48:20 PM »

I fly one on a PAW .09, It will fly the entire pattern well, must to the surprise of a couple a couple of my local compatriots.

Bill Little · « **Reply #8 on:** March 03, 2011, 06:49:38 PM »

Quote from: Rusty Pieper on March 03, 2011, 06:19:31 PM

I bought one these kits today. I have a fox .25 (old, old version) and a OS 15. Which would I use?

I posted a question in the engine section, not knowing this thread was going.

I am going to take the advice offered and make the wing longer.

Hi Rusty,

Use the lighter engine. And I would probably use the OS .15 anyway.

If you have the "old old" 3 bolt backplate Fox 25, that's what Don Still used in his Stuka. A much bigger airplane all around. And that engine will fly a Dolphin or Fancy Pants pretty easy. The Fox .25 could easily be used, but it might be more hassle trying to tame it down enough to be enjoyable to fly.

Built light, the Akromaster will do a full pattern on a .09-.10 size engine. Definitely make the wing to the full length of the LE, TE, and spar material that comes in the kit. It will be evident when you get the kit what everyone is talking about there.

Big Bear

Randy Ryan · « **Reply #9 on:** March 03, 2011, 06:54:15 PM »

Quote from: Rusty Pieper on March 03, 2011, 06:19:31 PM

I bought one these kits today. I have a fox .25 (old, old version) and a OS 15. Which would I use?

I posted a question in the engine section, not knowing this thread was going.

I am going to take the advice offered and make the wing longer.

OS .15 is all you need

Rusty · « **Reply #10 on:** March 03, 2011, 06:58:53 PM »

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Bryan Higgins · « **Reply #11 on:** March 03, 2011, 07:05:25 PM »

Hello Allen

I would just build the Akromaster as per plans. Only changes i would make
would be to use todays modern materials to assemble the model.

Powerplant - I would order a Brodak .15 No hassles and 4/2 break all day
long.

Bill Little · « **Reply #12 on:** March 03, 2011, 07:20:23 PM »

Quote from: Rusty Pieper on March 03, 2011, 06:58:53 PM

Is the the Fox you are talking about, Bill?

I will use the OS 15.

Thank you.

Hi Rusty,

That's the one. Absolutely a great "Classic" 4-2 stunt engine, almost as much power as the Fox.35. And it's built in the ".19" case which is light. (yeah, it isn't an Aero Tiger .36, but it is great for what it is) Got one in a Brodak Fancy Pants, and it does a great job. Don Still flew that engine in his 1960 World Championships Stuka, the one Ambroid kitted and RSM puts out now.

I have gathered a few over the years but only have one NIB example left......

Big Bear

Bill Little · « **Reply #13 on:** March 03, 2011, 07:21:49 PM »

Quote from: Bryan Higgins on March 03, 2011, 07:05:25 PM

Hello Allen

I would just build the Akromaster as per plans. Only changes i would make
would be to use todays modern materials to assemble the model.

Powerplant - I would order a Brodak .15 No hassles and 4/2 break all day
long.

HI Brian,

Why wouldn't you extend the wing? it's basically a "freebie". (curious)

Big Bear

ray copeland · « **Reply #14 on:** March 03, 2011, 08:13:43 PM »

Allen, i have built two and the biggest problems were not enough room for the tank i wanted to use and being nose heavy. So , my recommendations are to leave the nose length alone and add some tail weight if needed. The first one i cut the leading edge back and the second i did not, they both fly good. Both of mine have .15's and fly great on 52 foot lines. They are great trainers!

Clayton Berry · « **Reply #15 on:** March 04, 2011, 12:41:58 AM »

Mine had an OS 15 III and it flew fine. Any modern .10 - .15 is probably what you ought to consider.

Save the McCoy for uh, well, uh... Showing your grand kids how things used to be?

Bill Heher · « **Reply #16 on:** March 04, 2011, 02:42:25 AM »

Do a search for Akromaster mods- should pull up plenty of detail. short list from my experience. Any modern .10-.15 will fly it fine, choose a light engine if you have one available. Original had a Fox .15 I think- wich is pretty light.

1. Extend aft fuse 1 1/2 to 2 inchs with a piece of scrap- helps w/ balance
2. Extra wing area as described above/
3. Triangle stock on each side of fuse under stab to give more mounting area. Stab
get knocked off easily otherwise.
4. Adj leadouts- use the multiple holes joined by a slot style.
5. Solid gear mount- even better is sheet aluminum gear.
6. Lightweight wheels to help avoid nose heavy
7. Iron on film for wings, dope or Rust-o-elum paint for solid surfaces
8. 48' -52' .012" lines

Fly and smile!

Alan Buck · « **Reply #17 on:** March 04, 2011, 10:46:02 AM »

I have one for Diane with a os19 steel fin using 52' solids and should go to 55' with a 19 it will fast even with a 9x4 prop

George · « **Reply #18 on:** March 04, 2011, 02:54:59 PM »

Quote from: Rusty Pieper on March 03, 2011, 06:19:31 PM

I bought one these kits today. I have a fox .25 (old, old version) and a OS 15. Which would I use?

You didn't say which OS .15. If it is a steelfin MAX-III .15 with no muffler, it should fly great without modifications on 52' x .012 lines.

Quote

I am going to take the advice offered and make the wing longer.

By all means, if it is a newer OS .15 with muffler, use the extended wings. If it is the older one, extended wings will lighten the wing loading a bit.

I have two Akros. One is stock with a Fox .15X (with muffler), the newer one has extended wings with a Thunder Tigre .10 (with muffler). Everything except the wing is stock on both.

Good luck whichever way you go.

George

Allen Eshleman · « **Reply #19 on:** March 05, 2011, 08:37:22 AM »

Thanks guys,

I think I will go with the larger wing and the elongated fuselage and try to keep the wheel light. Since I don't want to buy a new engine, I will go with one of the McCoy 19s and see what happens. Thanks so much.

Bryan Higgins · « **Reply #20 on:** March 05, 2011, 11:25:27 AM »

Hi Bill

I just have learned by my own mistakes it's best to build a model the way it was designed and go
have fun flying it.
There are some steps you can change but be very carefull not to add to much wieght or change
the design characteristics of the model.

Sorry i have not been around for a while , been under the weather. I'll send some modeling pics
this month of what i've been working on. Thank Bryan Higgins

wwwarbird · « **Reply #21 on:** March 06, 2011, 09:34:40 PM »

Um, not done yet but here's mine...

Allen Eshleman · « **Reply #22 on:** March 07, 2011, 06:42:06 AM »

Thanks for the pictures. I like the wheel mounts. I have a pair that I will use. Did you do any modifications such as lenghening the wings?

wwwarbird · « **Reply #23 on:** March 07, 2011, 10:32:04 AM »

Allen,

I don't want to hijack your post here, but take a closer look at all the photos. This "Akromaster" has been very highly modified to resemble a full scale Cessna Agwagon cropduster. The only kit parts left in the model are the wing ribs and leading edge stock. I did make a couple of extra ribs and extend the leading and trailing edges to add the full bay on each wing. I trimmed all the ribs down by 1/16" around the perimiter so that I could add leading edge sheeting and capstrips. I also added the carved and hollowed the semi-scale "drooped" wingtips. Fuselage is all new with a nose tripler and the tail moment is longer. It has bigger (fixed) flaps, larger area tail surfaces all around, and aluminum landing gear. It's been hanging on the wall at this stage for at least four years now. I just keep ending up with another model to finish first.

john e. holliday · « **Reply #24 on:** March 07, 2011, 04:53:22 PM »

Hey, get it finished before spring gets here. I think it looks great and the grass needs fertilizer. Oh then again I don't see the spray apperatus.