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Author Topic: 1/2A proto at Whittier Narrows  (Read 6135 times)

Offline Mike Callas

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1/2A proto at Whittier Narrows
« on: June 17, 2014, 02:22:18 AM »
Ill be at SCAR race this weekend
Was thinking of building a 1/2 A proto
How many entries are typical?
I have a couple of piccos from DG I was going to use for FF but never did
May as well use them in the bullring
What do you use for a tank?
Are there options for a button bellcrank?

Thank you

Offline Motorman

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Re: 1/2A proto at Whittier Narrows
« Reply #1 on: June 22, 2014, 08:32:46 AM »
Hard tank, 10cc, crankcase pressure. When you needle it lean it down until it saggs then back it off and launch. Bladder tanks are ok but inconsistent due to stretching. If you use one fill it up the same amount every time will help.

Button bellcranks are nice but use double loops.

Offline Mike Callas

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Re: 1/2A proto at Whittier Narrows
« Reply #2 on: June 23, 2014, 01:38:17 AM »
Thanks Motorman.
I met Howard Doering and Joe today at the field. They had some good tips on getting a proto going.
I double loop my mouse lines. Unfortunately I cannot find anyone with button bellcranks.
Will a simple 3/8 oz brodak 1/2 a tank work??

Thanks again
Mike



















Offline Mike Callas

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Re: 1/2A proto at Whittier Narrows
« Reply #3 on: July 13, 2014, 09:25:24 PM »
1st attempt at 1/2A Proto.
6.5 oz less bellcrank. CG on the leading edge.
3/8 oz brodak tank
I put a quarter in for tip weight. Is that too much? Too little?

Offline Motorman

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Re: 1/2A proto at Whittier Narrows
« Reply #4 on: July 15, 2014, 03:47:29 PM »
If that's a suction tank get ready for it to die on take off unless your venturi is tiny.  My wing is shorter and i use 7g tip weight a quarter is 5g so I think your ok. Curious about that prop. Someone gave me something similar to mold but I never did. Where's the clear canopy, is that still in the rules?

MM
« Last Edit: July 15, 2014, 08:53:31 PM by Motorman »

Offline Mike Callas

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Re: 1/2A proto at Whittier Narrows
« Reply #5 on: July 16, 2014, 12:48:52 AM »
Why the canopy is so clear you can't see it in the pictures. But trust me its there (OK will be there).
Blue prop from global hobby in San Diego.
In order to use a bladder, how does one secure the filled balloon?
I can see it stretching out to the outboard wingtip in flight. Can I nail the loose end to the fuse or wing??

Mike

Offline Motorman

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Re: 1/2A proto at Whittier Narrows
« Reply #6 on: July 16, 2014, 07:47:13 PM »
A bladder tank is hard to manage and make consistent. I would try for a pressure tank.

If you want a bladder you can make a fiberglass tube to hold it or an aluminum can the right size. I made a stream lined kind of pouch on mine. Lean the needle down past the peak setting so it doesn't flood the engine before revs come up then open it up and let it go. Fill the bladder the same amount every time because of the stretching factor and 3-4 flights get a new bladder. I was using small surgical tubing but there might be something better from the 1/2a combat world.

MM

Offline Mike Callas

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Re: 1/2A proto at Whittier Narrows
« Reply #7 on: July 16, 2014, 08:52:33 PM »
Thanks for the suggestions Motorman.
I'm going to try to fly it this weekend.

Offline qaz049

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Re: 1/2A proto at Whittier Narrows
« Reply #8 on: July 17, 2014, 06:04:11 AM »

Half A Proto Speed to AMA rules is gaining in popularity here in Australia as well.

I'll attach some pics, of club members models (mainly Sweepers) and some details of my Profi 049 powered model. I use a bladder and made my own bobbin bellcrank. All work well sofar. The prop is a small APC, but I now have some Wilk carbon fibre two bladers. That Profi is one sweet little motor.

Offline qaz049

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Re: 1/2A proto at Whittier Narrows
« Reply #9 on: July 17, 2014, 06:22:10 AM »


These are earlier club mates models, both powered by Norvel 049's. New models are being built for the destroked Picco 049's.

Offline Mike Callas

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Re: 1/2A proto at Whittier Narrows
« Reply #10 on: July 17, 2014, 11:43:13 PM »
Awesome pics Clarence!!
Is that tube where you put the bladder?
I have a boatload of Cigar tubes. Light spun aluminum cigar tubes. Maybe I cab trim one to fit.
Where did you get the cool landing gear??

Mike

Offline qaz049

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Re: 1/2A proto at Whittier Narrows
« Reply #11 on: July 18, 2014, 05:21:07 AM »
Awesome pics Clarence!!
Is that tube where you put the bladder?
I have a boatload of Cigar tubes. Light spun aluminum cigar tubes. Maybe I cab trim one to fit.
Where did you get the cool landing gear??

Mike

Mike,

yes the bladder goes into the GF tube, it's inflated in-situ with about 20cc of fuel. The tube and undercarriage come from Steven Wilk. They are easy to make yourself though.

Offline Mike Callas

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Re: 1/2A proto at Whittier Narrows
« Reply #12 on: September 21, 2014, 07:40:37 PM »
Finally flew the 1/2 A proto,
Howard did the maiden flight and deemed the plane safe. I flew it a coupe of times and recorded a 72 mph run.
Thanks to Howard, Joe and racing guru Dave Hull for helping getting the motor started.
See you guys next race/meet.

Mike

Offline Motorman

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Re: 1/2A proto at Whittier Narrows
« Reply #13 on: November 29, 2014, 09:10:09 PM »

These are earlier club mates models, both powered by Norvel 049's. New models are being built for the destroked Picco 049's.


Those are some nice looking models. What's the wing span on those, is that a 25% stab?


MM

Offline Chris McMillin

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Re: 1/2A proto at Whittier Narrows
« Reply #14 on: January 06, 2015, 02:24:01 AM »
The wings and stabs look like 1/2A Hustlers turned around.
Chris...


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