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Author Topic: Big Smash, P-18 for EAA Family Flight Fest 2020  (Read 149 times)
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jim_buxton
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« on: February 12, 2020, 04:26:42 PM »

I was asked to come op with a new model for the One Design event we always run at the EAA indoor contest (AKA EAA Family Flight Fest) this year.  We phased out the Double Whammy and decided to replace it with a model that we equally simple, but could be flown i other events.
To accomplish those goals I decided to come up with a model that would be legal (and useful) for P-18.  The model is inspired by the popular "Mash-Up" that Rob Romash and I came up with for a previous EAA one design event.
I have submitted the plans to the Builders Gallery.

Here are the notes I included with the plans when I sent it out:
_______________________________________________________________________________________________________________________________________________________________________________________________________
The “Big Smash” is inspired by the popular one design “Mash-Up” designed for the EAA event by Rob Romash.  This larger version is designed to comply with the rules for P-18, which is becoming more popular as an introductory event to indoor flying.

Prototype built with 8-12 pound wood and came in at 7.6 grams. Using the sizes shown on the plan.  For hardware, see sources below.  Note, these are not required items for the one design event, just an idea of what I am doing.

I am using the 6" Igra/Czech prop from Volare:
https://volareproducts.com/index.php?main_page=product_info&cPath=56_42_50&products_id=98
Volare no-cal nose bearing.
https://volareproducts.com/index.php?main_page=product_info&cPath=56_40&products_id=1155
Small Brass washers:
https://volareproducts.com/index.php?main_page=product_info&cPath=56_40&products_id=152
Also using S-hook prop shaft from Peck:
https://www.wind-it-up.com/collections/prop-shafts-and-bearings/products/pa048  

Covering is veggie bags for the main panels, printed tissue for the tips and rudders to add some Romash-esque pizazz.  I adhered it with spray 77, but have since helped some scouts build these models and found that UHU glue stick works great to hold the veggie bag plastic on, and you can slide it around to adjust tautness very nicely on the strong structure of this model.
Wing dihedral can be single as shown or double poly at the tips.  Just so the projected span stays under the 18” P-18 limit you are legal.
I hope to build another one, and John Kagan is building one as well.
_____________________________________________________________________________________________________________________________________________________________________________________________________________________________
The event is just over a week away I guess, so I need to build another one.  John and I will try to post some pics of our builds here.  Below is a Youtube link to a video of the maiden flight of the prototype.  Enjoy!
Jim Buxton  
https://youtu.be/HlrjHcNKDiQ


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~Jim Buxton
Columbus Ohio
jim_buxton
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« Reply #1 on: February 12, 2020, 04:30:17 PM »

A couple shots of the prototype.
Attached files Thumbnail(s):
Re: Big Smash, P-18 for EAA Family Flight Fest 2020
Re: Big Smash, P-18 for EAA Family Flight Fest 2020
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~Jim Buxton
Columbus Ohio
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« Reply #2 on: February 12, 2020, 05:56:44 PM »

That's a neat design, looking forward to the plan.   I've not used one of those props --what is the mass of the 6"Φ version? How's it compare to a Tern?
« Last Edit: February 12, 2020, 06:12:36 PM by Indoorflyer » Logged
FlyF1D
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« Reply #3 on: February 12, 2020, 07:12:54 PM »

Here's some info on my Big Smash

I chose polyhedral tips, because that's the Romash way

Won't crumple the veggie bag as much next time. That works well for the thinner films, but is too much for this thickness

Teflon bushing fills out the prop hole while keeping it "unmodified"

Budget mag board worked nicely. $6 22GA sheet from home depot, $5 magnets from Amazon

Attached files Thumbnail(s):
Re: Big Smash, P-18 for EAA Family Flight Fest 2020
Re: Big Smash, P-18 for EAA Family Flight Fest 2020
Re: Big Smash, P-18 for EAA Family Flight Fest 2020
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John Kagan
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« Reply #4 on: February 14, 2020, 12:17:37 AM »

Hi Jim,
nice smooth flight and good endurance for first flights in video.

Have you gotten a sense yet what size rubber and how many turns have worked best so far for this model?

For example, .074 rubber,1.8g loop,
@ 1900 turns

Thanks again for sharing, john s.
« Last Edit: February 14, 2020, 01:05:25 AM by jswain » Logged
FlyF1D
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« Reply #5 on: Today at 09:57:19 AM »

Test session at the local gym: https://youtu.be/C3H0YIeH7ow
Attached files Thumbnail(s):
Re: Big Smash, P-18 for EAA Family Flight Fest 2020
Re: Big Smash, P-18 for EAA Family Flight Fest 2020
Re: Big Smash, P-18 for EAA Family Flight Fest 2020
Re: Big Smash, P-18 for EAA Family Flight Fest 2020
Re: Big Smash, P-18 for EAA Family Flight Fest 2020
Re: Big Smash, P-18 for EAA Family Flight Fest 2020
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John Kagan
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