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Author Topic: 1/2a Sig Akromaster  (Read 1512 times)

Offline ray copeland

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1/2a Sig Akromaster
« on: May 01, 2021, 07:42:41 PM »
From a Sig Akromaster kit, used the original leading edge, ribs and wingtips. Target weight was 10 oz. came in at 10.7. Norvel .061 with Brodak 1 1/4 oz tank. Put up 2 flights today, first one the prop wash was siphoning fuel from the tank. Fixed that and the second flight was great, did all maneuvers but the squares and four leaf, leaned out a little at the end and so ran the tank out, landing was perfect. 45 foot power pro lines and cox 5x3 prop, will try an apc 5.5x2.5 next time the wind dies enough to do 1/2a. Used light balsa for the replacement parts and changed the tailfeathers a bit.  I like it a lot!!!
« Last Edit: May 01, 2021, 08:33:44 PM by ray copeland »
Ray from Greensboro, North Carolina , six laps inverted so far with my hand held vertically!!! (forgot to mention, none level!) AMA# 902150

Offline john e. holliday

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Re: 1/2a Sig Akromaster
« Reply #1 on: May 01, 2021, 07:46:41 PM »
A 3 X 5 prop!!!   On my 1/2A's I usually use a 6 X 3 APC prop.  Glad the plane is working for you. H^^
John E. "DOC" Holliday
10421 West 56th Terrace
Shawnee, KANSAS  66203
AMA 23530  Have fun as I have and I am still breaking a record.

Offline ray copeland

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Re: 1/2a Sig Akromaster
« Reply #2 on: May 01, 2021, 08:19:31 PM »
Doc, it's a cox 5x3 rubber ducky!
Ray from Greensboro, North Carolina , six laps inverted so far with my hand held vertically!!! (forgot to mention, none level!) AMA# 902150

Offline Mark Mc

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Re: 1/2a Sig Akromaster
« Reply #3 on: May 01, 2021, 09:13:21 PM »
Ray, I would not use the rubber ducky again.  Those are not made for the high revs that a Novel will turn.  I shed a blade on a rubber ducky while running a Babe Bee that was running at almost 20K.  A tweaked Bee, but I didn't expect to get that high of an RPM.

Mark

Offline Larry Renger

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Re: 1/2a Sig Akromaster
« Reply #4 on: May 01, 2021, 10:42:00 PM »
Sadly, recent Cox props don’t seem to be as good as they should be. If you have one, flex it. If you see surface cracking, throw it away or return it to the vendor. Originally they could be bent double without harm.

The correct formula is VIRGIN Nylon6-6 with no regrind. Anything less is subject to fracture as noted. I had a recent prop shed a blade on starting! Ridiculous safety risk.
Think S.M.A.L.L. y'all and, it's all good, CL, FF and RC!

DesignMan
 BTW, Dracula Sucks!  A closed mouth gathers no feet!

Offline kenneth cook

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Re: 1/2a Sig Akromaster
« Reply #5 on: May 02, 2021, 04:11:33 AM »
               Ray, your weight is similar to my Stork. I too found the Cox 5x3 to work well for the Norvel. I thought I had a 5.5x2.5 which you mentioned but it was a 5.5 x 2. That turned out to be a real air beater. It needed more pitch for certain. The shape of the 5.5 x 2.5 is also slightly different but it works quite well for Norvel's. It just gets confusing when ordering as I discovered I had many of the 5.5 x 2's and no 2.5's.

           

Offline Larry Renger

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Re: 1/2a Sig Akromaster
« Reply #6 on: May 02, 2021, 06:13:47 AM »
I agree that the 5.5x2.5 works really well.
Think S.M.A.L.L. y'all and, it's all good, CL, FF and RC!

DesignMan
 BTW, Dracula Sucks!  A closed mouth gathers no feet!

Offline 944_Jim

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Re: 1/2a Sig Akromaster
« Reply #7 on: May 02, 2021, 08:02:56 AM »
Wow, the plane looks great!

So the kit was built stock except you are using a 1/2 engine on it? Or did you use the wing parts but built the wing with smaller rib-spacing and scale the rest of the plane down to a more typical side for 1/2A?

With Sig Akros going for around $50 on eBay, this opens up a lot of quick build planes around the .061 engines.
« Last Edit: May 02, 2021, 03:32:58 PM by 944_Jim »

Offline ray copeland

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Re: 1/2a Sig Akromaster
« Reply #8 on: May 02, 2021, 09:38:37 AM »
Sig lists the kit for $31.97. Buy one and you can make more like i did. I only used the ribs, leading edge, spars and wing tips from the kit. It is the full 34 inch wingspan. I don't like the split elevator so i made a full one and put it on the back end with the rudder chopped a little short. I used contest balsa for all the parts i copied from the originals and used 1/16 ply for the doublers. I worried about the weight but the .061 pulls it fine, i believe a norvel .049 would do also. The trailing edge was the hardest part to copy, also used smaller size maple motor mounts, on the next one i need to weigh the difference between bolting the engine on or using blind nuts. This was a fairly easy build and flies great. 
Ray from Greensboro, North Carolina , six laps inverted so far with my hand held vertically!!! (forgot to mention, none level!) AMA# 902150

Offline Dan McEntee

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Re: 1/2a Sig Akromaster
« Reply #9 on: May 02, 2021, 06:27:47 PM »
  Am I just not seeing it, or have you not mentioned fuselage construction?  What are some details on the fuselage?
    Thanks a lot,
  Dan McEntee
AMA 28784
EAA  1038824
AMA 480405 (American Motorcyclist Association)

Offline ray copeland

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Re: 1/2a Sig Akromaster
« Reply #10 on: May 03, 2021, 04:38:50 AM »
Dan, the fuse is just a copy of the original but with 1/4 inch light balsa. I made one out of 3/8 like the original but eventually cut back to 1/4 inch, one coat of poly acrylic and one coat of clear poly along with 1/6 ply doublers. In the picture is everything needed to make another, just size the motor cutouts to fit. The ribs are the same with the exception of the three center ones are undersized to fit the 1/6 sheeting. The original wood weighed 9.8 ounces alone, i have another built with the original wood that flies fine with a os 15.
Ray from Greensboro, North Carolina , six laps inverted so far with my hand held vertically!!! (forgot to mention, none level!) AMA# 902150

Offline Dan McEntee

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Re: 1/2a Sig Akromaster
« Reply #11 on: May 03, 2021, 07:30:30 AM »
Dan, the fuse is just a copy of the original but with 1/4 inch light balsa. I made one out of 3/8 like the original but eventually cut back to 1/4 inch, one coat of poly acrylic and one coat of clear poly along with 1/6 ply doublers. In the picture is everything needed to make another, just size the motor cutouts to fit. The ribs are the same with the exception of the three center ones are undersized to fit the 1/6 sheeting. The original wood weighed 9.8 ounces alone, i have another built with the original wood that flies fine with a os 15.

  Thanks Ray. I have built and flown several of these over the years with .15's and a Fox .19 but have always wanted to try one with one of the new 1/2A engines and built light. Just may get to that soon I hope. Thanks again,
   Dan McEntee
AMA 28784
EAA  1038824
AMA 480405 (American Motorcyclist Association)

Offline Mark Mc

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Re: 1/2a Sig Akromaster
« Reply #12 on: May 06, 2021, 12:11:43 AM »
I need to get off my butt and finish my most recent Akromaster.  I was originally going to make it a full fuse electric, but lost the motivation for 'trons.  So I measured, and a Norvel will fit between the sides in the engine bay.  I'll probably do a .061, but I do have two .074's that I picked up for $20 a piece.  They're the old LMH setups, but I figure I can cut down the head fins so it doesn't look too goofy and fly them CL.


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