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Building Tips and technical articles. => 1/2 A building. => Topic started by: Miguel Poduje on April 02, 2021, 10:49:23 PM
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Hi.
I'm looking for twin or multiengine plans for 1/2 A engines.
I like profiled semi scale models and now I am looking for a multi engine model.
I've tried looking for the sterling p-38's plans but only found parts in outerzone.
Thank you very much and please take care
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Hip pocket aeronautics has the complete plan and templates. you have to register to down load but they don't sent spam and it is a safe site.
https://www.hippocketaeronautics.com/hpa_plans/details.php?image_id=10874
The Bell YFM-1 Airacuda is pretty neat at
https://outerzone.co.uk/plan_details.asp?ID=8208
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The 1/2A Sterling P-38 has been reproduced by Dave Cowell of DPC Models/AeroWerkes. I know he was taking some time off, but is starting to cut kits again.
You want to look at his Short Release Kits (SRKs), which are short kits with plywood wheel blanks, plywood bellcrank, and square stick leading edges.
I have one, and it is pretty faithful to the original.
What kind of engines are you planning on? Reed or rotary valve? Scale, semi-scale, or sport? Built up or all profile, slab wing?
I'm a sucker for twins, and have been collecting plans.
This is twin Norvel .074s.
https://youtu.be/943S3SyWiwE
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Then there is AMA plan #508 B-25 Mitchell, with video of one flying on a 1/2A video from California. I have traffic from the builder regarding this one. I'll try to find the YouTube video.
And I love the Brown-Novitnik Mosquito at 26" for twin Babe Bees. I can add the link to both on RCGroups...the BN Mossie includes a rough plans sheet. My own rendition of this one is at 23" with twin Cox PeeWees (Dave Cowell DPCModels first-run prototype). I can supply a picture and links to the he RCGroups build).
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Pat King ,PDK LLC has a P-38 Laser cut kit for 1/2 A. and bigger .Check him out on the Vendors on this forum. He has lots of scale kits.
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I started to build a Black Hawk XF-5F Skyrocket, but decided it was too small so I up-scaled it about 20%. It worked well.
In the kit, they use a simple 1/8" balsa wing, which is not NEAR enough to keep two engines together.
The prototype is chronically tail heavy as several modelers learned.
I got NO satisfaction with TeeDee .020's. Black Widows were good. TeeDee .049's were and still are, the BEST.
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Just a word about running a Cox reed with the cylinder ahead of the prop, they get hot!
Motorman 8)
Not mention possible reed damage and NOT using the internal bushing as designed.
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The Mitchell:
https://youtu.be/0VbfAbpUDS8
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And the Mosquito:
https://www.rcgroups.com/forums/showthread.php?2741283-1-2A-Mosquito-w-built-up-wing-profile-fuselage
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If I build another 1/2A twin I will include a fuel shutoff to avoid the single engine part at the end of the flight. Measuring fuel seldom works well enough.
I would say, skip the idea of finding plans and just scale something that you and the judges will like.
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That's me flying my B-25 in the video. It was built 26 years ago from Model Aviation plans for our club 1/2A contest.
I changed the ribs to a symmetrical airfoil so it will fly upside down.Two Cox reed valve .049's are plenty of power.
It was covered in silk but over time it got brittle and cracked. So recovered it with polyspan and repainted it.
Haven't flown it yet since the repaint.
Bill
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I am using two 8cc fuel tanks on the back of the motors. 1/2 A reed valves don't have a lot of fuel draw
so a single tank would be a challenge.
Bill
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I am using two 8cc fuel tanks on the back of the motors. 1/2 A reed valves don't have a lot of fuel draw
so a single tank would be a challenge.
Bill
I agree. Two reedies on a common tank won't work.
But maybe piping both air vents to a common inlet would make a way to stop them both within a reasonable time.
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I always start the outboard motor first so it quits first. In the video of my B-25 one motor quit early.
That video flight was the first flight in several years on those motors. What I found is 1/2A's need to be run
often for good motor runs.
Bill
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If you search through Pat's kit offerings here you'll find some very high quality designs. y1
https://stunthanger.com/smf/pdk-llc-laser-cut-kits/
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The guys have offered some wonderful suggestions and I'd like to offer mine, if I may. I fell for the Grumman Widgeon and can suggest the plan, if you'd like.
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My A26A Counter Invader is an award winning profile scale 1/2A airplane. Full size .pdf files of any of my airplanes are $5.00 per set emailed to your inbox.
Pat
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Brodak Twin Mustang
https://brodak.com/control-line-kits/brodak/1-2-a-series/f82-twin-mustang-kit.html
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That Brodak F-82 has been reported to build nose heavy...especially with Babe Bees.
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(https://outerzone.co.uk/images/_thumbs/plans/12794.jpg)
VD~
(https://travelupdate.com/wp-content/uploads/2019/09/Dornier-DO-X-San-Diego-Air-and-Space-Museum-Archive-AL-135B-139-1245x640.jpg)