Author Topic: 2012 Stunter - Thundervolt - A Build LOG (Read 22104 times)

Crist Rigotti · « **Reply #100 on:** January 02, 2012, 07:19:30 PM »

I'm baaaaack!
The last couple of days I've been thinking about the fuselage. I decided to redesign the front end to accommodate a "top loader" for the battery. I redid the drawing today and would like your comments.

Bob Hudak · « **Reply #101 on:** January 02, 2012, 08:50:27 PM »

Looks pretty good Crist. Dowel in the front I see but what keeps the backside of the hatch in place ? Neodymium magnets maybe? I have 2 on the backside of my hatch and plan on using a canopy latch bought off Ebay on the front of hatch.

Crist Rigotti · « **Reply #102 on:** January 02, 2012, 09:06:59 PM »

Bob,
I use the same latch on some of my R/C ships.

You are correct on using magnets on the aft side. They will by on the aft bulkhead and will be positioned vertically. They will not be on the "bottom" of the hatch positioned horizontally.

Dean Pappas · « **Reply #103 on:** January 02, 2012, 09:44:58 PM »

H Crist,
Looks good.
I have tried to think through the same sort of setup as you suggest, and I have one thought.
The latches, like the one Bob pictured, are very tidy, and if the latch is placed in the hatch, not in the fuselage, then one hand is all it takes to grab the sides of the hatch and pull the pin back and remove the hatch.
This frees up the other hand to hang onto the ship. We have achieved single-hand, no-tools battery access, and along with it access to the hidden disarming plug!

I'll say it again, nice work,
Dean

Crist Rigotti · « **Reply #104 on:** January 03, 2012, 06:28:51 AM »

Quote from: Dean Pappas on January 02, 2012, 09:44:58 PM

H Crist,
Looks good.
I have tried to think through the same sort of setup as you suggest, and I have one thought.
The latches, like the one Bob pictured, are very tidy, and if the latch is placed in the hatch, not in the fuselage, then one hand is all it takes to grab the sides of the hatch and pull the pin back and remove the hatch.
This frees up the other hand to hang onto the ship. We have achieved single-hand, no-tools battery access, and along with it access to the hidden disarming plug!

I'll say it again, nice work,
Dean

Dean,
Good idea. I'll look into that.

A hidden disarming plug? My thoughts were that the plug should be readily accessable. Would a hidden plug be in compliance with the "Brett Buck" proposed rule?

Dennis Adamisin · « **Reply #105 on:** January 03, 2012, 07:09:20 AM »

Top hatches are great. I am tyring to do a side hatch too - so I can miss the forward canopy on some of my (pending) Classics.

BTW I agree that the arming plug should be exposed/accesible without being hidden, so that is how I am doing all mine.

Dean Pappas · « **Reply #106 on:** January 03, 2012, 11:48:34 AM »

It's a fair question.
To my way of thinking, one-handed, no tools, access suffices.
For appearance points' sake, some sort of external marking " EMERGENCY SHUTDOWN ACCESS" or something that sounds scale-like works.
It remains to be seen what the exact wording will be.
I did suggest to Brett that the access merely needed to be "no tools required", but that was long ago in and probably lost in a long thread.

take care,
Dean P.

Crist Rigotti · « **Reply #107 on:** January 03, 2012, 08:38:55 PM »

Quote from: Dean Pappas on January 03, 2012, 11:48:34 AM

It's a fair question.
To my way of thinking, one-handed, no tools, access suffices.
For appearance points' sake, some sort of external marking " EMERGENCY SHUTDOWN ACCESS" or something that sounds scale-like works.
It remains to be seen what the exact wording will be.
I did suggest to Brett that the access merely needed to be "no tools required", but that was long ago in and probably lost in a long thread.

take care,
Dean P.

Dean,
Thanks for the candid reply. We'll just have to wait and see.

Crist Rigotti · « **Reply #108 on:** January 03, 2012, 08:47:59 PM »

I started the fuselage tonight. The sides are made from 3/32 6# balsa and the doublers are 1/64 ply. I had to join several pieces of wood to be able to have a wood blank large enough for each side. I usually place a splice up front where it is reinforced by the 1/64 doublers. The sides are drying with the firewall end shimmed up 3/32 to help with the curvature into the spinner. While I had enough epoxy I laminated the LE former made up of 3/32 balsa and 2 pieces of 1/64 ply. I also made up the stab LE former from 1/16 balsa and 1 piece of 1/64 ply. The balsa grain runs crosswise, while the 1/64 ply grain runs up and down.

Seeing I have access to a large format printer I made up a drawing that extends the outline of the fuselage sides and the location of each bulkhead. A very accurate method of laying out the fuselage.

Wynn Robins · « **Reply #109 on:** January 03, 2012, 11:04:14 PM »

my next plane will have the hatch latch AS the arming switch - so you only "click" the hatch in place once you are ready to fly..... I have tested it with the sermos power poles and they make a nice snug connection - with my hatches being on the inboard side - it also has no stress on any of the fittings...

I like your design - looks nice and tidy......something I struggled with early on... HA

Mark Scarborough · « **Reply #110 on:** January 03, 2012, 11:10:42 PM »

Wynn,
interesting, I was cogitating that very same idea the other day while driving to work ( I have an hour drive to work)

as an alternate for emergency disconect, providing the judges with a 3 pound sledge might work?

Christ, the build is coming along nicely,,

Dennis Adamisin · « **Reply #111 on:** January 03, 2012, 11:39:08 PM »

Quote from: Wynn Robins on January 03, 2012, 11:04:14 PM

my next plane will have the hatch latch AS the arming switch - so you only "click" the hatch in place once you are ready to fly..... I have tested it with the sermos power poles and they make a nice snug connection - with my hatches being on the inboard side - it also has no stress on any of the fittings...

I like your design - looks nice and tidy......something I struggled with early on... HA

Crist does first class work - enough to keep my stuff OUT of the forum!

Wynn, I like your idea for the side hatch that is "latched" by the built in power pole arming circuit!

Dean Pappas · « **Reply #112 on:** January 04, 2012, 11:36:13 AM »

Quote from: Wynn Robins on January 03, 2012, 11:04:14 PM

my next plane will have the hatch latch AS the arming switch - so you only "click" the hatch in place once you are ready to fly..... I have tested it with the sermos power poles and they make a nice snug connection - with my hatches being on the inboard side - it also has no stress on any of the fittings...

I like your design - looks nice and tidy......something I struggled with early on... HA

That's bleeping brilliant!

Regards and a genuflection or two ...

Dean

Wynn Robins · « **Reply #113 on:** January 04, 2012, 04:17:42 PM »

thanks folks (sorry for hijacking your thread Crist)

sometimes simple ideas come to me.... HA. - with the hatch idea - it is easy to pull the hatch off using the "pin" I use as the opening device - so if there are any issues - you can disconnect as quik as any other device - no sledge hammer required Mark!!!

Crist Rigotti · « **Reply #114 on:** January 04, 2012, 06:11:54 PM »

Quote from: Wynn Robins on January 04, 2012, 04:17:42 PM

thanks folks (sorry for hijacking your thread Crist)

sometimes simple ideas come to me.... HA. - with the hatch idea - it is easy to pull the hatch off using the "pin" I use as the opening device - so if there are any issues - you can disconnect as quik as any other device - no sledge hammer required Mark!!!

You're forgiven Wynn!

Crist Rigotti · « **Reply #115 on:** January 04, 2012, 09:00:19 PM »

Tonight's progress on the fuselage. The doublers are glued in and the fuselage sides are cutout for the wing and stab. The formers are located and the battery tray anchors are glued in. I also cut the hatch for the adjustable elevator linkage. I lined the hatch and its opening with 1/32 basswood. I always leave a little gap between the side and the hatch to allow for paint build up.

Tomorrow I'll spend the evening making up the bulkheads. Then this weekend I join the fuselage sides.

Crist Rigotti · « **Reply #116 on:** January 05, 2012, 09:09:22 PM »

I made the formers tonight. I used some spray adhesive to glue the plan to the wood. Then I cut out the formers. F1 and F2 are made out of 3/16 ply and due to the 2 degree right thrust I sanded in a small angle on the side of each former.

Tomorrow I'll join the fuselage sides.

Dennis Adamisin · « **Reply #117 on:** January 05, 2012, 09:43:25 PM »

More gorgeous work Mr "R"!!!

Crist Rigotti · « **Reply #118 on:** January 06, 2012, 08:07:32 AM »

Thank you Dennis.

Crist Rigotti · « **Reply #119 on:** January 06, 2012, 10:01:10 PM »

Tonight I joined the fuselage sides. I used my jig that I made up some time ago. When I tape down the plan to the work surface I align the center line to the line on the work surface. If you look close you'll see some triangle shaped cut out of the plans to reveal the line on the work surface. I aligned the jig blocks to the outline of the fuselage, then I aligned the fuselage sides fore and aft, then inserted the formers. It took very little adjusting the jig blocks so that the fuselage sides matched the plans. The formers and everything fit very nicely. The tail post is made up from some small TE stock with 1/32 balsa in between to form the lower rudder hinge slot. I then made up the diagonal formers. Very pleased with the way it turned out. Tomorrow I'll add the tri stock to the nose and start making the jig to mold the top/bottom blocks.

Mark Scarborough · « **Reply #120 on:** January 06, 2012, 11:52:33 PM »

Crist,
it looks beautifull,, nice and tidy,,

oh dont forget to fuel proof the fuel tank bay

Igor Burger · « **Reply #121 on:** January 07, 2012, 01:02:06 AM »

Quote from: Mark Scarborough on January 06, 2012, 11:52:33 PM

oh dont forget to fuel proof the fuel tank bay

exactly ... the best will be some high temp dope for chimney ... I heard lipos like to burn

Crist Rigotti · « **Reply #122 on:** January 07, 2012, 08:23:35 AM »

Quote from: Igor Burger on January 07, 2012, 01:02:06 AM

exactly ... the best will be some high temp dope for chimney ... I heard lipos like to burn

LOL!

Crist Rigotti · « **Reply #123 on:** January 08, 2012, 09:12:08 PM »

I trial fit the motor and it fit well. Pretty tight but good. I then made up the rear shaft support using a 5mm flange bearing and some 1/16 fiberglass board I had. I followed my drawings and it fit perfectly! No shimming, no nothing. I made up the battery floor and added some tri stock above the motor area. Then I added the stab shelf. You'll notice a 1/4 hole in the shelf. It is there to provide an outlet for the stab air as it gets heated when I re-tighten the Monokote from time to time. Plus, I think it's a good idea to let it breathe. I then glued the patterns for all the formers on some 1/16 or 1/8 balsa as required.

I started to make the mold for the top and bottom blocks. I used some of that unused flooring for the base. I glued on a top view drawing and cut and sanded it to shape. It matched the fuse exactly. I then cut out the formers from some 3/32 birch ply that I had. After shaping and sanding to size, I glued them to the bottom block. I then cut out some 2# foam and epoxied the foam to the form. I'm letting dry overnight. Oh, yeah, I used a black magic marker on the edges of the formers so I will be able to tell when I'm sanding down far enough when shaping the mold.

Wynn Robins · « **Reply #124 on:** January 08, 2012, 09:14:59 PM »

can I just ask how the rear bearing is held in place - is it just press fit into the board?

thanks

Crist Rigotti · « **Reply #125 on:** January 08, 2012, 09:19:29 PM »

Quote from: Wynn Robins on January 08, 2012, 09:14:59 PM

can I just ask how the rear bearing is held in place - is it just press fit into the board?

thanks

Good question Wynn. It is a light press fit then I use a little JB Weld applied sparingly with a toothpick.

Allan Perret · « **Reply #126 on:** January 09, 2012, 08:31:13 AM »

Looks like you have right thrust built into the motor mount. How much ?
Or is it just the angle of the picture that makes it look like that ?

Crist Rigotti · « **Reply #127 on:** January 09, 2012, 10:08:53 AM »

2 degrees Allan.

Ron Hook · « **Reply #128 on:** January 09, 2012, 04:22:45 PM »

I have been watching your building progress with great interest. Great job!! Are you thinking about making your plans available for others to purchase? I know that I would be interested and hopefully others also.

Ron Hook
Goodyear, AZ

Crist Rigotti · « **Reply #129 on:** January 09, 2012, 04:26:31 PM »

Ron,
Thanks for the kind words. When I'm done and it flys, then you can have a copy. Remind though. I suffer from O.L.D.

Crist Rigotti · « **Reply #130 on:** January 09, 2012, 09:03:07 PM »

The top/bottom block mold has been carved and sanded to the proper contour. After I sanded it I usually add several coats of Polycrylic. This time I used some 3/4 oz fiberglass and 2 coats of Polycrylic. Looks like this method is going to work well. I also am making up the forward top block mold. It'll be finished the same as this mold.

wwwarbird · « **Reply #131 on:** January 09, 2012, 09:09:37 PM »

Lookin' good Crist!

Crist Rigotti · « **Reply #132 on:** January 10, 2012, 09:08:57 PM »

Thanks Wayne.

I shaped the forward top block mold tonight and the first aft top block is on the mold and drying. It will come off in 2 days.
I also finished cutting out all the bulkheads. I decided to eliminate the false bulkheads because I think the 3/32 sheet I'm using for the blocks is stout enough not to need those bulkheads.

On to the front end of the fuselage while the fuselage top/bottom blocks are being formed.

Crist Rigotti · « **Reply #133 on:** January 11, 2012, 09:27:53 PM »

Tonight's progress was I put the first balsa on the forward top block mold. It'll come off in 2 days. The aft top block will come off the mold tomorrow. I added the 1/2 tri stock to the bottom of the nose, 3/16 bottom sheeting with the grain crosswise, the 3/8 chin block, and the 1/2 nose block with the 1/32 ply nose ring. I used Pica Gluit glue because I'll be doing a lot of sanding across the glue joints and the Pica glue sands very well and doesn't leave a "lump" like using CA does.

I put in a 1/4 hole where the nose strut will come through the bottom sheeting and lined the hole with 1/4 aluminum tubing.

I did notice that I won't be able to get to the aft screws on the battery tray from on top. So I installed some 2-56 blind nuts and drilled out the aft tray mounts to 3/32. I'll be able to get to these screws from the cooling hole on the bottom. So far so good. I'm pretty sure the fuselage will come in under my weight budget even enough to make up for the other parts that are slightly over budget. All-in-all, I just make have it come in at 50 ounces or less....we'll see.

Crist Rigotti · « **Reply #134 on:** January 12, 2012, 09:53:16 PM »

The top block came off the mold tonight. Worked very well.
Here is a picture of the tool I use to trim the molded balsa. It is the same height as the base of the mold and I rounded the corners and glued on a new #11 blade. To trim the balsa, I just put some pressure on the assembly and slide the tool along the side of the mold. Off comes a very close trimmed piece of molded balsa. I mark the fuselage sides where the formers are located. I then tape the balsa to the fuselage after carefully aligning it to the sides and mark the former location from the fuselage sides to the balsa. I then glue in the formers at the pencil marks. I then trim the front and aft face and then slide it along some sandpaper that I have glued down on a flat surface to true up the bottom edge. Here's a picture of the finished top block resting on the fuselage. BTW, the top block weighs 7 grams ready to install. The 3/32 wood molded well and will provide plenty of strength.

I then trimmed and sanded the nose into a "blocked" configuration. I made up the top motor block and the angled bulkhead. The bulkhead is made from 1/16 basswood to provide some durability for the hatch parting surfaces.

Tomorrow the forward top block comes off the mold and Saturday the bottom aft block comes off the mold.

john e. holliday · « **Reply #135 on:** January 13, 2012, 09:14:23 AM »

That is awesome as usual.

Crist Rigotti · « **Reply #136 on:** January 13, 2012, 09:28:10 PM »

Thanks Doc.

Tonight I shaped the front end and cut the cooling holes. For the block that starts at the LE of the wing, I sanded in the scoop using some 1 1/4 Schedule 40 PVC pipe I had laying around. I lined the scoop with 1/32 balsa. I have some more shaping and sanding to complete the nose.

Tomorrow I get the molded bottom block off the mold. Then Sunday the forward top block comes off the mold, if I need it.

Crist Rigotti · « **Reply #137 on:** January 14, 2012, 09:09:05 PM »

Today I finished all the top and bottom blocks and the hatch. Finished sanding the nose. The total weight of all the blocks and the hatch came out to 25 grams. Next up is making the mount for the start switch.

wwwarbird · « **Reply #138 on:** January 14, 2012, 09:37:00 PM »

So it looks like the nose is going to stay bigger than the spinner diameter for a propwashy cooly sucky intake action? (sorry if I'm getting too technical)

Dennis Adamisin · « **Reply #139 on:** January 14, 2012, 10:10:29 PM »

Yeah wwarbird, that motor is gonna get frostbite from all the cooling air. ABSOLUTELY GREAT job Crist!

Crist Rigotti · « **Reply #140 on:** January 14, 2012, 10:34:11 PM »

Quote from: wwwarbird on January 14, 2012, 09:37:00 PM

So it looks like the nose is going to stay bigger than the spinner diameter for a propwashy cooly sucky intake action? (sorry if I'm getting too technical)

You nailed it!

Crist Rigotti · « **Reply #141 on:** January 14, 2012, 10:42:18 PM »

Quote from: Dennis Adamisin on January 14, 2012, 10:10:29 PM

Yeah wwarbird, that motor is gonna get frostbite from all the cooling air. ABSOLUTELY GREAT job Crist!

Thanks Dennis. What I'm a bit concerned with is slotting the battery tray for all that air to prorerly flow across the battery surfaces so it can do its job.

While working on the front end and the hatch, I think I figured out the placement of the electronics. The ESC will reside below the battery tray along with the start switch. The timer will reside on the outboard (maybe) side. While I can move the battery fore and aft for balancing, I do think a forward position is a bit preferred.

Dennis Adamisin · « **Reply #142 on:** January 15, 2012, 12:58:42 AM »

I hear you. Air intakes are easy enough, I'm having a devil of a time locating effective outlets...

Crist Rigotti · « **Reply #143 on:** January 15, 2012, 08:43:22 AM »

Yikes! I think I'd better take out the trash.

john e. holliday · « **Reply #144 on:** January 15, 2012, 01:16:21 PM »

That's not so bad, I still see a clean spot on the floor.

PJ Rowland · « **Reply #145 on:** January 15, 2012, 05:09:52 PM »

Chris :

You are clearly mocking the rules of "Bin Jenga"

The stack may build as high as possible with additional junk being placed on top.
You may balance against a wall
Once the additional loads of rubbish cannot be placed on the stack in any capacity without falling to the floor
Game over - bin must be emptied by the offender.

wwwarbird · « **Reply #146 on:** January 15, 2012, 07:17:52 PM »

Quote from: Crist Rigotti on January 14, 2012, 10:42:18 PM

What I'm a bit concerned with is slotting the battery tray for all that air to prorerly flow across the battery surfaces so it can do its job.

Without looking back, that would all depend on where the battery is in line in relation to the intended airflow path.

I'm going to describe the following only because sometimes people do miss the obvious, not implying that you are here Crist.

If the battery is "ahead" of the battery tray, there is no reason other than weight to put vents directly "behind" or underneath the battery because the battery will be there blocking the airflow anyway. Depending on the compartment, as many vents as possible should be incorporated in the tray around where the battery is positioned on it to allow the most possible airflow.

Crist Rigotti · « **Reply #147 on:** January 15, 2012, 08:42:32 PM »

Quote from: wwwarbird on January 15, 2012, 07:17:52 PM

Without looking back, that would all depend on where the battery is in line in relation to the intended airflow path.

I'm going to describe the following only because sometimes people do miss the obvious, not implying that you are here Crist.

If the battery is "ahead" of the battery tray, there is no reason other than weight to put vents directly "behind" or underneath the battery because the battery will be there blocking the airflow anyway. Depending on the compartment, as many vents as possible should be incorporated in the tray around where the battery is positioned on it to allow the most possible airflow.

Wayne,
Your last statement is what I'm determining. Of course those slots will depend on where the battery is located fore/aft. Also how to get the air to flow over all exposed sides and not just 1 or 2. In the Spring when I fly it, I can try different trays and can instrument the battery sides with 3 different temps sensors. It might be worth experimenting to get some good data on the subject.

Crist Rigotti · « **Reply #148 on:** January 15, 2012, 08:46:59 PM »

Ahhh.....all better now.

wwwarbird · « **Reply #149 on:** January 15, 2012, 10:12:53 PM »

What's that YELLOW stuff on the wall?