Logo
Builders' Plan Gallery  |  Hip Pocket Web Site  |  Contact Forum Admin  |  Contact Global Moderator
December 10, 2018, 05:25:49 AM *
Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with email, password and session length
 
Home Help Search Login Register
Pages: [1] 2   Go Down
Print
Author Topic: Comet Dime Hurricane  (Read 657 times)
0 Members and 1 Guest are viewing this topic.
vtdiy
Bronze Member
***

Kudos: 6
Offline Offline

United States United States

Posts: 78


Topic starter


Ignore
« on: December 05, 2018, 11:35:37 AM »

It's been a very long time since I've built a stick and tissue full fuselage model, and only a  couple even then. And in fact, only one successful rubber model. But friends have encouraged me to join them in some Comet Dime scale WW2 builds. Their aim is a Glastonbury contest, but mine is just to get 30 seconds out of it without hitting a wall at a nearby gym!

I remember trying Stirling and Guillow's models as a kid and being greatly disappointed by the starved dog look and warped airframes that I managed. Hoping that I can do something like this now 50+ years later, and have it come out looking and flying okay. I'm encouraged by Mike's Flying Scale pages full build for beginners section, and I'm going to try to follow that with this plane.

Today, I looked through the balsa I had and found a fairly light weight sheet of 3/32". This plane is actually meant for 1/16" but all I have of that is hard and heavy. I think I'll just sand the parts down a little to get 1/16". There isn't much wood in this plane from the looks of it.

Okay, I just copied the plans by a laser printer, and ironed the patterns them onto the balsa sheet I have.

http://www.sredmond.com/Models/Hurricane/HurricaneComet-Printwood.jpg
Comet Dime Hurricane
Logged
vtdiy
Bronze Member
***

Kudos: 6
Offline Offline

United States United States

Posts: 78


Topic starter


Ignore
« Reply #1 on: December 05, 2018, 12:55:34 PM »

I sharpened my exacto knife, and then carefully worked my way around the biggest fuselage former - #7, not trying to cut through in one go, as I would have when I was young. I understand grain better now! Then I cut out the tiny stringer notches.The wood is pretty soft, so I was afraid of pulling out a chunk. But I got through that okay. That felt great, my first piece!

Then I tried thinning it down to 1/16" by sliding it over 400 grit paper. That was taking forever, so I switched to 80 grit (the only other  type I had). Worked but toward the end I did manage to rip out one of the notches. Okay, first piece, not so good. I decided, it was probably a lot better idea at this point to sand down the whole balsa sheet, rather than single parts at a time.

I used a sanding block with 80 grit glued flat to a piece of foam, and this did a good job of removing wood. I kept checking all around with a caliper to make sure I didn't sand too thin or make the sheet uneven. Got there eventually. Next time I'm near a hobby shop I'll stock up on 1/16th"!

http://www.sredmond.com/Models/Hurricane/HurricaneComet-Thinning.jpg
Comet Dime Hurricane
Logged
vtdiy
Bronze Member
***

Kudos: 6
Offline Offline

United States United States

Posts: 78


Topic starter


Ignore
« Reply #2 on: December 05, 2018, 02:42:55 PM »

I just cut out all of the fuselage formers. That was hard. It's really hard for me to cut the notches without shredding or breaking off the corner of the piece. But I got most of them done without a break. They do seem very fragile in this soft balsa. Maybe I should have picked the harder piece. Anyway, here they are:

http://www.sredmond.com/Models/Hurricane/HurricaneComet-FusFormers.jpg
Comet Dime Hurricane
Logged
vtdiy
Bronze Member
***

Kudos: 6
Offline Offline

United States United States

Posts: 78


Topic starter


Ignore
« Reply #3 on: December 05, 2018, 04:22:25 PM »

Thanks Sundance. What are your other tools for cutting out notches?


I cut out some stringers and the wing root rib and glued them together. I'm not sure what the dotted line is on the rib -- I thnk maybe for a fairing? I don't have instructions with this plan, so some things are guesses.


http://www.sredmond.com/Models/Hurricane/HurricaneComet-StringersOn.jpg
Comet Dime Hurricane
Logged
vtdiy
Bronze Member
***

Kudos: 6
Offline Offline

United States United States

Posts: 78


Topic starter


Ignore
« Reply #4 on: December 05, 2018, 05:23:00 PM »

Hmmm. I've just realized there's no top (plan) view of this fuselage??!

I guess the fuselage sections are probably rectangular and I could measure the upper formers at the notches, and then cut the lower crosspieces the same length.

But that would work only for formers that are vertical. There are two angled formers: #5 and #6. And if there's any fore and aft fuselage taper where they are, the lower cross members would not be cut to the same length as the upper formers.

......Okay, I see a provided #I6 bottom cross member in my balsa sheet. But that's a little mixed-up, too. The perspective view of the fuselage shows it aligned with former #5, not former #6. So I think they numbered that cross member wrong. Should be #I5, not #I6

So the only puzzle left is what is the length of the 1/16" square stock cross member that's aligned with former #6? Should I just assume that the fuselage doesn't taper here. I kinda doubt that, because upper formers #5 and #6 are different widths.

I guess that one will have to wait and be cut to fit. Unfortunately that's where you'd probably want to first fit crosspieces before bending the sides in.  Oh well, we'll figure it out....
Logged
vtdiy
Bronze Member
***

Kudos: 6
Offline Offline

United States United States

Posts: 78


Topic starter


Ignore
« Reply #5 on: December 05, 2018, 05:40:38 PM »

One other question -- maybe somebody here can answer this. There's a "main framework" shown of 1/16" longerons and framing (which I've built), and then there's a "side stringer", which I haven't yet added.

Is that supposed to go outside of the "main framework"? I'm guessing that's there to give more shape to the sections, instead of being slab sided? Or is it let in flush as pieces?

Probably be the former...... but I'm not sure. It would be nice if these plans showed a sample construction section.
Logged
skyraider
Platinum Member
******

Kudos: 91
Offline Offline

United States United States

Posts: 1,253

WWW

Ignore
« Reply #6 on: December 05, 2018, 07:19:41 PM »

Quote
Is that supposed to go outside of the "main framework"?

Yes. Used to mess me up too long ago.

Skyraider
Logged
vtdiy
Bronze Member
***

Kudos: 6
Offline Offline

United States United States

Posts: 78


Topic starter


Ignore
« Reply #7 on: December 05, 2018, 07:23:46 PM »

Thanks, Skyraider.
Logged
faif2d
Platinum Member
******

Kudos: 31
Offline Offline

United States United States

Posts: 1,146


Sun came up I was here to see it = good day



Ignore
« Reply #8 on: December 05, 2018, 07:51:32 PM »

Try using a double edge razor to cut the notches. I think that even a scalpel is to dull to cut them in soft balsa. Use something like this to cut the back of the notches.
Attached files Thumbnail(s):
Re: Comet Dime Hurricane
Re: Comet Dime Hurricane
Logged

I used to like painting with dope but now I can't remember why!    Steve Fauble
vtdiy
Bronze Member
***

Kudos: 6
Offline Offline

United States United States

Posts: 78


Topic starter


Ignore
« Reply #9 on: December 05, 2018, 07:58:43 PM »

Thanks Faif2d!

Is that a piece of razor blade glued to a stick, cutting that notch?
Logged
Balsa Ace
Gold Member
*****

Kudos: 24
Offline Offline

Canada Canada

Posts: 452


FAC Member



Ignore
« Reply #10 on: December 05, 2018, 09:16:02 PM »

Good luck with your Hurricane build,Vtdiy.

Scott
Logged

Hawker Sea Fury FB.11
HMCS Magnificent
VF-871   RCN
Indoorflyer
Gold Member
*****

Kudos: 7
Offline Offline

United States United States

Posts: 317



Ignore
« Reply #11 on: December 05, 2018, 11:32:22 PM »

The dotted line represents the long "root rib" of the wing panel. (Labeled Part A in wing drawing)  It extends aft, since it also forms the base of the trailing edge fillet (W-5).  The wing root rib (A) butts against the fuselage side, and is glued to part 15 which is part of the fuselage side frame.  
Logged

Make the same mistake on both sides; nobody will notice...
vtdiy
Bronze Member
***

Kudos: 6
Offline Offline

United States United States

Posts: 78


Topic starter


Ignore
« Reply #12 on: December 05, 2018, 11:50:48 PM »

Thank you, Scott!

Thanks IndoorFlyer, that explains it perfectly.
Logged
faif2d
Platinum Member
******

Kudos: 31
Offline Offline

United States United States

Posts: 1,146


Sun came up I was here to see it = good day



Ignore
« Reply #13 on: December 06, 2018, 07:38:15 AM »

Vtdiy, yes that is a small piece of a razor blade.  If you have a high carbon steel one they can be snapped, if the blade is stainless it can be cut with a pair of scissors and one side of the cut will not curl.  I can not remember which side so you will have to experiment.
Logged

I used to like painting with dope but now I can't remember why!    Steve Fauble
calgoddard
Gold Member
*****

Kudos: 17
Offline Offline

United States United States

Posts: 907


AMA, NFFS & FAC Member



Ignore
« Reply #14 on: December 06, 2018, 10:48:37 AM »

vtdiy -

You can use what is called a "notching tool."

Here is Norm Furutani's description of a notching tool -

"I use a piece of firm balsa sheet the same thickness as the spar or longeron. CA some 180 grit sandpaper to the edge and you have a perfect notcher. If the notch is too loose, sand the sides of the notcher until it fits. To control the depth of the notch, glue a rail on the side of the notcher. If you are doing formers or other fragile pieces, back the part with a notched piece of 1/8 or 3/16."

I use a very hard piece of 1/16-inch square x 3-inch balsa to make a notching tool for notches sized to receive 1/16-inch stringers or spars.  Even better is a 1/16-inch square piece pieces of bass wood of similar dimensions.  Apply CA to one side of a segment of the pieces of wood that is about 1-inch long.  Press this side against a sheet of suitable grain sandpaper.  Use a very sharp Xacto knife to slice away the excess sandpaper on each side of the piece of wood.  

It may be preferable not to sand all the notches into the formers and ribs until the fuselage and wing are mostly assembled.  Otherwise the notches do not line up and often the stringers and spars are difficult to insert and/or end up wavy.

I bought a fancy notching tool some years ago that is made of Aluminum and has detachable and adjustable sanding planes for sanding 1/16, 3/32, and 1/8-inch notches.  
Logged
vtdiy
Bronze Member
***

Kudos: 6
Offline Offline

United States United States

Posts: 78


Topic starter


Ignore
« Reply #15 on: December 06, 2018, 10:53:14 AM »

Thanks Faif2d, will try one!

calgoddard, that sounds like a great idea!

I like making tools, so I'll try both -- I'm sure there's situations where each works well.
Logged
calgoddard
Gold Member
*****

Kudos: 17
Offline Offline

United States United States

Posts: 907


AMA, NFFS & FAC Member



Ignore
« Reply #16 on: December 06, 2018, 11:06:06 AM »

vtdiy -

When building your next model, you may decide to defer sanding the notches until the fuselage and wing are partially assembled. If that is the case, use a metal ruler and mark where the notches should be sanded with a fine point marking pen. This way the notches will line up and the stringers and spars will be easier to insert and will not be wavy along their lengths.
Logged
atesus
Gold Member
*****

Kudos: 21
Offline Offline

United States United States

Posts: 657




Ignore
« Reply #17 on: December 06, 2018, 11:50:12 AM »

Volare sells an excellent notcher tool.

http://volareproducts.com/index.php?main_page=product_info&products_id=253

-Ates
Logged
vtdiy
Bronze Member
***

Kudos: 6
Offline Offline

United States United States

Posts: 78


Topic starter


Ignore
« Reply #18 on: December 06, 2018, 12:09:41 PM »

Thanks again calgoddard -- I'll try that with the wing, since the ribs haven't been cut out yet.

Atesus, thanks.
Logged
calgoddard
Gold Member
*****

Kudos: 17
Offline Offline

United States United States

Posts: 907


AMA, NFFS & FAC Member



Ignore
« Reply #19 on: December 06, 2018, 12:46:29 PM »

Atesus -

Agreed, the Volare notching tool is an excellent, versatile product. It's the one I referred to at the end of Reply #14.
Logged
vtdiy
Bronze Member
***

Kudos: 6
Offline Offline

United States United States

Posts: 78


Topic starter


Ignore
« Reply #20 on: December 06, 2018, 06:03:51 PM »

Very frustrating today, it really reminded me of the same experience with stick and tissue kits I had as a kid. To start the day, I happily glued the tailposts together, and then glued in former #7. Things seemed nicely aligned and everything looked fine. When that was dry, I gradually added more members and lower crossbraces. Starting to look like something! But the problems started when former #6 split while I was holding things together waiting for glue to dry.

This former is shaped like a wishbone with the grain running vertically. It has practically zero strength at center, and two long levers. It's designed to break, really. Actually, Former #5, which is similar actually just broke when I picked it up, earlier. But I had glued that one back together.

This kind of design with short curves of cross grain wood would never work in any full sized structure, and it doesn't work very well in a model either. I ended up making two more former #6's, before I got one that I didn't break while installing. I have to admit that during this process, a couple other parts split or let go. I don't feel like I'm really ham-fisted, it was just some really fragile parts, and no real building jig to hold parts together. So it stopped being fun for awhile.

Anyway I got things together eventually and the alignment looks reasonable. Not perfect.... replacing parts didn't help compared to the original careful setup. Well, letting it dry overnight before touching it again. Maybe installing the stringers tomorrow will strengthen and stiffen things up.
Logged
OZPAF
Palladium Member
********

Kudos: 167
Offline Offline

Australia Australia

Posts: 4,460



Ignore
« Reply #21 on: December 06, 2018, 06:42:05 PM »

VTDIY perhaps it would be worth adding a cross brace at the bottom of the former between the longerons. It should be out of the way of the rubber and wouldn't affect the appearance of the canopy frame formers.
I agree - it's not good design.
John
Logged
vtdiy
Bronze Member
***

Kudos: 6
Offline Offline

United States United States

Posts: 78


Topic starter


Ignore
« Reply #22 on: December 06, 2018, 07:10:37 PM »

OZPAF, thanks!

That's actually exactly what I did to finally get it in place without breaking. I put a 1/16" brace across just in back of the former location, let that dry, then put the former in against that.  That way there was no pressure trying to hold the sides in while gluing it in place.

I went out down town to do an errand, and now back, I think the whole thing looks kind of cool again! Good to get away sometimes and come back to it with a fresh eye.
Logged
vtdiy
Bronze Member
***

Kudos: 6
Offline Offline

United States United States

Posts: 78


Topic starter


Ignore
« Reply #23 on: December 06, 2018, 09:06:44 PM »

The next question I have is, how does the wing dihedral construction work?

The plan shows a straight section extending out both sides of the fuselage for one wing bay, then the dihedral starts. There are no braces, no double ribs, no lapped spars, or anything I'm familiar with in this kind of joint.

Does the single rib sit vertical, or square to the outer wing panel, or halfway between?

Do the 1/16" sq stringer/spars simply but together over the single rib? I can't imagine how that will hold.
Logged
weetle
Silver Member
****

Kudos: 6
Offline Offline

United States United States

Posts: 170


Forgets to take pictures frequently



Ignore
« Reply #24 on: December 06, 2018, 09:27:07 PM »

So Between A and B is a 1/16th stringer (yellow). This is the last wing stringer I put in.
W-7 and 8 (red) determine dihedral for the wing. You can glue ribs A and B to W-7/8.
Glue a stringer (blue) between C, D, and E. This stringer must go to just the edge of the B rib. But do that after you glue the leading/trailing edges and the wing tip. I prefer basswood for this on this kind of scale, it adds strength with very little weight.
Then when that is dry, you can keep the inner section with A and B ribs pinned while you raise the outer portion so that the stringer is resting on the angle of W-7/8 and glue it.

Also this construction holds very well. If you are overly concerned with strength on the dihedral you can use fillets on the leading and trailing edges.
Attached files Thumbnail(s):
Re: Comet Dime Hurricane
Logged
Pages: [1] 2   Go Up
Print
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.21 | SMF © 2015, Simple Machines Valid XHTML 1.0! Valid CSS!