Electrocution of a 1973 RCM Acro Star Bipe - RC Groups
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Sep 29, 2016, 12:33 PM
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Electrocution of a 1973 RCM Acro Star Bipe


Acro Star Biplane

Designed by Don Dewey in 1973. This Bipe is easy to build with straight top and bottom wings, and has 820 square inches of wing area and the span is 51". The original Acro Star's were powered by .40 to .60 Glow engines and weighed in between 5 1/4 pounds to 7 pounds dry or without fuel. I loved the designs of Ken Willard, Don Dewey and others during the 70's and wanted to build this as an electric conversion.

This was planned to be my Winter project but framed the fuse in the Spring and built the wings in our HOT Summer days where it was too hot to fly.

I downloaded the plans from Outer Zone and had them printed by RC Groups Member "Hemikiller", then reached out to Bob at LDS and had him cut the wing ribs and formers.

I changed the fuse construction to allow a nice size top hatch to swap out 4S5300 Lipo's. I also changed the fuse sides to 3/32 from 1/8 light ply sides. I used another piece of 3/32 as a doubler from the firewall to the trailing edge of the wing. I also used 1/16 balsa for the turtle deck sheeting.

The only thing I changed on the wings was 1/16 balsa sheeting instead of 3/32.

For power, I am using a Cobra 4120/14 (710Kv), Scorpion 70 Amp Esc. and Castle Creations BEC. I plan to use either an APC 128E or 13x8E prop.

The balsa cowl is held on with magnets and 1/8" dowel pins.

The rudder and elevator servos are Futaba S3002's and are mounted behind the wing. A hatch gives access to the servos as well as a cooling exhaust opening. I am using two JR 321's for the aileron servos.

The wheel pants are from Horizon Hobbies Rhapsody 25E ARF.

I still have to fabricate the wing struts and planed to have them use a 1/16 dowel to align with the bottom wing and magnets to hold to the top wing.

I didn't want to do a traditional build thread but just show some pictures of my conversion to maybe inspire someone else to convert one of many old RCM plans. I know my friend Mark Rittinger has done that with his Omen III redesign, what a great flying pattern airplane from back in the day!

I did a weight check this morning with all servos, motor, battery etc. it weighs 4 pounds 15 ounces. So it should come in under 6 pounds and fly great.

Any questions let me know.

Denny
Last edited by Dennis Sumner; Dec 05, 2016 at 04:08 PM.
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Sep 29, 2016, 01:21 PM
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Ken Myers's Avatar
Glad to see you are putting the rainy days to good use.

As I told you, that is my favorite plane of all time, and it was also the plane I was flying when I met Keith Shaw, all of those long years ago.

Can't wait to see it flying.
Sep 29, 2016, 01:43 PM
I just want to go fly!
walter3rd's Avatar
That's a gorgeous looking bipe! Gets me excited for my sig hog bipe kit I just ordered yesterday! It will be my 8th kit but first bipe kit build. Your is a beautiful example of biplane style. Well done! - what's the wingspan on this girl? That's quite light! I love the cowl, I plan to do the same on my hog bipe. It looks way better than cheeks imho. Walt --- ps. - your build is crazy clean! Are you a surgeon?
Last edited by walter3rd; Sep 29, 2016 at 01:51 PM.
Sep 29, 2016, 02:07 PM
Wanted for breaking Ohm's Law
Dennis Sumner's Avatar
Quote:
Originally Posted by Ken Myers
Glad to see you are putting the rainy days to good use.

As I told you, that is my favorite plane of all time, and it was also the plane I was flying when I met Keith Shaw, all of those long years ago.

Can't wait to see it flying.
Ken,

I got most the building done when it was so hot.....been sanding and doing little fiddly bits this week.....glad I went out flying last Saturday and Sunday!
Sep 29, 2016, 02:09 PM
Wanted for breaking Ohm's Law
Dennis Sumner's Avatar
Quote:
Originally Posted by walter3rd
That's a gorgeous looking bipe! Gets me excited for my sig hog bipe kit I just ordered yesterday! It will be my 8th kit but first bipe kit build. Your is a beautiful example of biplane style. Well done! - what's the wingspan on this girl? That's quite light! I love the cowl, I plan to do the same on my hog bipe. It looks way better than cheeks imho. Walt --- ps. - your build is crazy clean! Are you a surgeon?
Walt,

I forgot to add details of wingspan, it is 51". I edited my first post to include wingspan...thanks!

No not a surgeon.....just an anal retired Project Manager....
Last edited by Dennis Sumner; Oct 12, 2016 at 06:44 AM.
Sep 29, 2016, 02:48 PM
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EloyM's Avatar
ELECTROCUTION?? Shouldn't it be: Electrification? Electrifying?
Sep 29, 2016, 03:10 PM
Wanted for breaking Ohm's Law
Dennis Sumner's Avatar
Quote:
Originally Posted by EloyM
ELECTROCUTION?? Shouldn't it be: Electrification? Electrifying?
You are correct......it's a little tounge in cheek....
Oct 11, 2016, 09:56 PM
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Steve Merrill's Avatar
That looks great. Did you get her covered?
Oct 12, 2016, 06:01 AM
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Dennis Sumner's Avatar
Not yet Steve,

I've been doing a lot of sanding and fabricating N struts......
Oct 12, 2016, 06:12 AM
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Ken Myers's Avatar
I'm old. I forget, but I thought the top wing had a 60" span. No?
Oct 12, 2016, 06:27 AM
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Dennis Sumner's Avatar
Quote:
Originally Posted by Ken Myers
I'm old. I forget, but I thought the top wing had a 60" span. No?
Both wings are 51" span.

How's your back doing? Sunday flying was okay but pretty lumpy air with the "breeze"...
Last edited by Dennis Sumner; Oct 12, 2016 at 06:44 AM. Reason: Loose nut on keyboard
Oct 12, 2016, 07:31 AM
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Ken Myers's Avatar
Chalk one up for faulty memory of a 70-year-old. Thanks for the info.

The back is somewhat better; ice, heat and tens unit have helped. Leaving for the 10 hour trip to Crystal Falls and hour drive into the woods at 4 tomorrow morning. We'll see how that goes.

I did keep an eye on the winds on Sunday, and they did appear a bit brisk, but doable. Glad you made it out.
Oct 13, 2016, 09:25 PM
Gravity sucks.
mrittinger's Avatar
Nice looking ship Denny. Red n white?
Oct 13, 2016, 09:50 PM
Registered User
Can't wait to see the pix when she is covered! Nice build. Should fly great.
Oct 14, 2016, 05:55 AM
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Dennis Sumner's Avatar
Thanks Mark and VA....I am planning white, orange and brown (Ultracote).

Still have some sanding to go before covering, I wanted to get the N struts fitted.

Denny


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