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Author Topic: SV-11 electric ARF/ARC take apart - method #1  (Read 3284 times)

Offline Mike Alimov

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SV-11 electric ARF/ARC take apart - method #1
« on: September 09, 2019, 02:44:13 AM »
Here are some pictures of method #1 for a one-piece wing. Used on many RC airplanes. Tested on electric version of the SV-11 ARF/ARC.   I had a detailed multi-step tutorial written up (took about 2 hours), and the entire post got wiped out by the forum software due to the picture size limitation.  I don't have time to re-type everything, but will do my best do answer specific questions.

Offline Mike Alimov

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Re: SV-11 electric ARF/ARC take apart - method #1
« Reply #1 on: September 09, 2019, 02:45:14 AM »
...more pictures.

Offline Mike Alimov

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Re: SV-11 electric ARF/ARC take apart - method #1
« Reply #2 on: September 09, 2019, 02:46:28 AM »
Canopy attaches using rare earth magnets (Hobby King).

Offline Shorts,David

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Re: SV-11 electric ARF/ARC take apart - method #1
« Reply #3 on: September 10, 2019, 01:49:54 PM »
HI MIke, me again. This is more what I had imagined coming from an RC background. Regarding fuselage strength, are you worried at all the the fuselage could snap downward since the top part of the fuselage is removable and possibly held by magnets? or does the top piece provide structural strength as well? Also, are the nylon bolts 1/4-20? Any chance of them sheering off? I've seen them sheer off on pylon racers.

Beautiful job. I'm just putting stuff together in my head right now.
David

Offline Mike Alimov

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Re: SV-11 electric ARF/ARC take apart - method #1
« Reply #4 on: September 10, 2019, 03:17:28 PM »
Hi David,
yes, the nylon bolt are 1/4-20, and yes, I was initially concerned about the structural integrity of the fuselage, since the removable canopy part provides zero contribution to strength here.  However, I'm happy to report that neither the nylon bolts nor the fuselage had any cracks or failures so far.  Probably because our stunters don't experience nearly the kinds of G loads seen on the pylon racers.
To be honest, I've never been a big fan of cutting out half to two-thirds of the fuselage to create space for the wing to go in, which is how almost every stunt ship has been built for the last six decades.  But that's how the SV-11 ARF came, and I took a chance - I had no other option, since I had to squeeze myself, two boys, 2-3 airplanes with flight box and luggage into a Ford Escape.

That's why I specifically indicated that this has been tested on SV-11 ARF, electric version only.  Other airplanes may have even less "meat" left around the wing, no plywood doublers, and run combustion engines which vibrate like crazy.  So if you decide to design for this method of disassembly, keep those factors in mind.  I've actually had an RC ARF (Giles 202, the subject of several control line conversions) come apart in the air during an official flight of the 2nd round of the Cleveland contest.  It failed exactly at the point where the fuselage had the least amount of wood left to allow for an enormously thick wing; the vibration from the Saito 56 did its part too...  It made for a traumatic, if memorable, experience.

Offline Tim Wescott

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Re: SV-11 electric ARF/ARC take apart - method #1
« Reply #5 on: September 10, 2019, 05:39:05 PM »
The first cut at take-apart airplanes (that I know of, from reading magazines) was in the 1990's, and did something similar.  One-piece wing, leave the tail feathers on, and have parting lines under the wings with an itty bitty section through the fuselage top.  It worked, AFAIK.

I think the whole removable-wing (and tail) thing was driven more by the size requirements for luggage in international flights.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline BYU

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Re: SV-11 electric ARF/ARC take apart - method #1
« Reply #6 on: September 12, 2019, 09:59:55 AM »
The first cut at take-apart airplanes (that I know of, from reading magazines) was in the 1990's, and did something similar.  One-piece wing, leave the tail feathers on, and have parting lines under the wings with an itty bitty section through the fuselage top.  It worked, AFAIK.

I think the whole removable-wing (and tail) thing was driven more by the size requirements for luggage in international flights.

I think you will find the first “take aparts” of “modern” stunt planes were from the late 60’s in Europe. Jim Mannal, and Claus Maikis had take apart planes then, Jim being acknowledged as the designer of take aparts initially, and my understanding this was largely to help them with transport as European cars were smaller and couldn’t accommodate families and full size planes at the same time. His system involved the wing being bolted in on the bottom. Al Rabe developed take aparts also in the 70's and Paul Walker came up with his own take apart system in the 80’s which was also copied by many other designers. More recently there are the ingenious systems developed in Eastern Europe based on a central Aluminum spar.


Offline Shorts,David

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Re: SV-11 electric ARF/ARC take apart - method #1
« Reply #7 on: September 12, 2019, 10:22:36 AM »
I've got one better. John Coasby, designer for the old British magazine, has take aparts. The Icarus with it's 67" w.s. is a take apart. Designed 1951. Of course it is held together more like a free flight plane. There is nothing precision about rubber bands. Although with the wing epoxied on it flies very nice.

Offline Tim Wescott

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AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline TDM

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Re: SV-11 electric ARF/ARC take apart - method #1
« Reply #9 on: September 20, 2019, 10:21:38 AM »
Nicely done Mike. If anyone has worries with the magnets holding things in place then a little piece of clear tape will take care of the problem. 
Each goal you meet is a moment of happiness
Happiness is the harmony between what you think and what you do. Mahatma Gandhi

Offline Steve Nelson

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Re: SV-11 electric ARF/ARC take apart - method #1
« Reply #10 on: February 18, 2021, 06:06:42 PM »
I was initially concerned about the structural integrity of the fuselage, since the removable canopy part provides zero contribution to strength here.  However, I'm happy to report that neither the nylon bolts nor the fuselage had any cracks or failures so far.

Hi Mike.  I am fascinated by your post of the Electric SV-11 ARF wing take off method.  You wrote that back in 9/10/2018 and you state then so far nothing broken. 

Would you update your comment on the strength and integrity now on your Electric ARF SV-11? 

I am so hoping that it worked because I would like to copy that.

Steve - Ready to go in Circles again!

Offline Mike Alimov

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Re: SV-11 electric ARF/ARC take apart - method #1
« Reply #11 on: February 21, 2021, 07:31:12 AM »
I was initially concerned about the structural integrity of the fuselage, since the removable canopy part provides zero contribution to strength here.  However, I'm happy to report that neither the nylon bolts nor the fuselage had any cracks or failures so far.

Hi Mike.  I am fascinated by your post of the Electric SV-11 ARF wing take off method.  You wrote that back in 9/10/2018 and you state then so far nothing broken. 

Would you update your comment on the strength and integrity now on your Electric ARF SV-11? 

I am so hoping that it worked because I would like to copy that.

Steve - Ready to go in Circles again!

Steve, the SV-11 is still alive and well, and the take-apart system has held up remarkably well, even after a couple of unrelated accidents that required mild repair elsewhere in the fuselage.  Overall, I'm very happy about the decision to go with this take-apart system, as it has made my life so much easier in terms of storage, transportation, maintenance and repair.

If you are actually going to build this way, here a few details that didn't get captured in text (refer to pictures above):

- Before gluing the wing halves together, make inserts out of 1/2" hard balsa where the leading edge carbon rods will reside, and glue them into each half from the inside of the first rib bay using epoxy or thin CA.  The inserts must make contact with both ribs and the sheeting.  Stock leading edge alone does NOT have enough wood/strength to properly capture the rods! There must be at least 1" of wood in the area where pins will reside.
- Once the wing halves are flued together (don't forget to install the bellcrank pushrod first), the trailing edge area gets reinforced with 1/16" plywood plates, top and bottom, and the entire center section of the wing gets laminated with 2 - 3 oz/yd fiberglass cloth/tape about 2" wide, using thin epoxy.
- After that, the leading edge receives 1/8" carbon rods/pins (thin CA or epoxy), and the trailing edge gets drilled for 1/4-20 nylon bolts.  Install flap horn, and the wing is ready.
- On the fuselage side: I used 1/4" aircraft plywood to hold the back of the wing, and simply drilled and tapped it for 1/4-20 thread.  You could also use blind nuts.  This 1/4" plywood plate gets glued into two 1/8" ply cradles which are laminated to the sides of the fuselage.  All assembly is done using high quality epoxy (I recommend West Systems 105 resin with 205 hardener; a quart-size kit will last a long time and is WAY stronger than any hobby-grade epoxies out there, like Zap or Bob Smith).  The leading edge pins get captured in a 1/8" aircraft ply plate installed from the inside of the battery compartment, again using epoxy.  All assembly operations happen while monitoring incidence angles using Robart incidence meters or similar, and jigs to hold things in place (however primitive they may be).
- A comment on holding the canopy hatch using magnets.  This system has worked for us for hundreds of flights, including on very windy days, without a problem.  But as Murphy's Law has predicted, the only fly-away incident with the canopy happened during my son's official flight at Dayton last year, which cost him 1st place in Advanced.  So, no more magnets for us, and we will be switching to spring-loaded canopy latches.  We get those either at HobbyKing or GatorRC.

Good luck!  If you have any questions, post them here or send me a PM.

Offline Steve Nelson

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Re: SV-11 electric ARF/ARC take apart - method #1
« Reply #12 on: February 21, 2021, 12:06:00 PM »
Thanks for the timely response Mike.

I was ready to glue the wing in but I will now change course and go with your mod.  I like the idea that I can make small trim adjustments to the control throws during early trim flights.   Re: Magnets for the canopy, Maybe your Son pushes tighter outside square corners than you.  ;-)

I was thinking about putting a dowel in the front bulkhead of the hatch and a pair of magnets near the slanted back half.  That might distribute the load and the airflow will help keep it secure.  (Just yesterday I blew a canopy off my 78" Extreme Extra 300 R/C that used two spring loaded latches.  I fired my mechanic because he (I) didn't tug on the cover to make sure the latches were engaged.  Murphy and his brother at work.

Thank you for your post and the pictures.


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