Fiddlers Green

Downloadable Fun!
It is currently Wed Dec 13, 2017 1:33 am

All times are UTC - 7 hours




Post new topic Reply to topic  [ 12 posts ] 
Author Message
PostPosted: Wed May 07, 2008 4:11 pm 
Offline
Paper Model Overlord
User avatar

Joined: Fri Oct 06, 2006 1:15 pm
Posts: 528
Location: Alameda CA
Having gotten into trouble in the topic below, accept my apologies, and for those who would like to be able to make propellors that look like this ---

Image

--- By way of atonement I've posted here the parts sheet of my scratchbuiilt 1/60 scale Avenger propellor ---

Image

--- and assembly instructions below. I hope you'll find this miniature a nice detail touch for future models, and not too terribly difficult to assemble. The blades are a photograph of an actual TBM propellor blade, with the Hamilton Standard decal enhanced by shrinking a full scale copy of the decal down to 1/60th. While the prop is a TBM prop, the general configuration is identical to many of the hydromatic propellors used on countless aircraft, with the only variation (for modelling purposes) the radius and aspect ratio of the blades, which can be easily adjusted to suit by using any photo editing software.

NOTE: You made need to enlarge the image here - the blades are 1-5/16" root to tip at 1/60th scale.


To begin - some nomenclature:

The blade halves need no introduction, but the rest of the parts do.

The blue-yellow stick figure at the right is the "spider" that the finished blades are glued to, both anchoring their 120 degree orientation from each other and their pitch. The spider gets folded up to 4-ply thickness for strength.

Just below the blades at the left are their three "root collars". These are wrapped around the blade roots and represent the main body of the hub.

Next to the root collars are the two "hub collars". They form the front and back of the hub (and are identical).

The cross-hatched parts are the three "hub flanges". These are folded over the edge of a piece of thin cardboard to give them thickness (and hence the cross hatched area to give you something large enough to fold). They're fitted between adjacent hub collars and represent the hub flange and its bolt bosses (note the tiny twin boltheads visible on each flange).

Finally, the piece at the bottom is the "piston dome". This is curled up and glued into the front hub collar, finishing the propellor. It represents the dome housing the pitch changing hydromatic piston. (The propellor is constant speed - a governor geared to the crankshaft maintains constant RPM by increasing or decreasing oil pressure against the piston in the dome, which rotates a cam that changes blade pitch. Desired RPM is set in the cockpit, which establishes a nominal pitch: flat pitch for high RPM (takeoff), and high (fat) pitch for low RPM (cruise). High RPM flat pitch produces lower airspeed but increased climb; low RPM high pitch produces high airspeed but decreased climb).


STEP 1.

Don't cut anything yet. Grab a scoring tool and score the following folds:

Spider fold lines.

Hub Flange fold lines (both of them - they're VERY close together, the thickness of a cardboard apart).

Hub collar fold lines (for doubling over).


STEP 2.

Now cut the sub assemblies apart, as below:

Image


STEP 3.

The blades are so thin it's best to pre-curl them while they're still together on the sheet, to prevent inadvertant creasing. Curl them up pretty tight - their roots will need to be full half cylinders when finished.

Image

Cut the blades apart, trim them not quite to the finish edge and tighten their curl even more (using a thin rod as shown).

Image

Trim them to their finish edges and curl their roots even more tightly (using a thinner rod as shown).

Image

Don't forget to tint their cut edges! A pencil is exactly the right shade and texture of color to use on flat black propellor blades

Image


STEP 4.

Glue the blade halves together. Let the roots dry as shown as an ellipsoid - don't try to make the roots cylindrical until the glue has dried.

Image

Glued and dried blades should look like this

Image

Image


When all the blades have been glued, you'll have the beginning of a first rate propellor!

Image


TO BE CONTINUED --- (Other duties call)


Last edited by airportkid on Sat May 10, 2008 2:32 am, edited 1 time in total.

Top
 Profile  
 
 Post subject:
PostPosted: Wed May 07, 2008 4:40 pm 
Offline
FG Origami Master
User avatar

Joined: Tue Feb 19, 2008 10:01 pm
Posts: 438
Location: Arlington, WA
wow!! :shock: :shock: I've wantin' to build more realistic props ever since I saw an old thread called "proper propellers" or something like that, but my attempt at scratch building one didn't work out.
with slight modifications these parts could be used for the F4F, F6F, SBD,
F2A, F4U-1...... maybe I'll build a few airplanes for a change...

_________________
Currently working on: Brewster Buccaneer
Recently completed: NA BT-9 in 1/112th.

"It's not enough that we do our best; sometimes we have to do what's required." - Churchill


Top
 Profile  
 
 Post subject:
PostPosted: Wed May 07, 2008 6:03 pm 
Offline
FG Origami Master

Joined: Sun Mar 05, 2006 6:58 am
Posts: 176
Location: Ocean Isle Beach,N.C.
Wow..No atonement needed by me. I have mostly carved wooden props when appropriate. I am now building a Hellcat and am going to attempt your neat design. Thanks


Top
 Profile  
 
 Post subject:
PostPosted: Wed May 07, 2008 6:33 pm 
Offline
Botbuster Master
User avatar

Joined: Thu Apr 28, 2005 5:08 pm
Posts: 2345
Location: HARTSHORNE, OKLA.
thats an excellent post....thanks alot. :D :D :D

_________________
Laterz
Possm_23
Never say anything you wouldnt think out loud!
Take your time leavin.....but hurry back!!!!
Every tub has to sit on its own bottom!!!!


Top
 Profile  
 
 Post subject:
PostPosted: Wed May 07, 2008 11:35 pm 
Offline
Supreme Paper Commander
User avatar

Joined: Mon Sep 25, 2006 10:42 am
Posts: 3075
Location: Papillion, NE
SUPER- DUPER!!!! That's pretty neat. Thanks!


Top
 Profile  
 
 Post subject:
PostPosted: Fri May 09, 2008 11:35 am 
Offline
Paper Model Overlord

Joined: Fri Mar 30, 2007 1:29 pm
Posts: 600
Location: Maryland
Dude I love you! that will be a great addition to just about all of my models thank you thank you thank you!


Top
 Profile  
 
 Post subject:
PostPosted: Fri May 09, 2008 1:32 pm 
Offline
FG Scorer
User avatar

Joined: Wed Sep 15, 2004 8:58 am
Posts: 108
Location: Phila. PA USA
WOW! I'm going to try that on my B-24.


Top
 Profile  
 
 Post subject:
PostPosted: Fri May 09, 2008 2:17 pm 
Offline
FG Origami Master
User avatar

Joined: Tue Feb 19, 2008 10:01 pm
Posts: 438
Location: Arlington, WA
do I dare try this in 1:87 scale? it would be really really tiny...

_________________
Currently working on: Brewster Buccaneer
Recently completed: NA BT-9 in 1/112th.

"It's not enough that we do our best; sometimes we have to do what's required." - Churchill


Top
 Profile  
 
 Post subject:
PostPosted: Fri May 09, 2008 5:04 pm 
Offline
Paper Model Overlord
User avatar

Joined: Fri Oct 06, 2006 1:15 pm
Posts: 528
Location: Alameda CA
WII wrote:
do I dare try this in 1:87 scale? it would be really really tiny...

I haven't tried it but if you used typing paper rather than cardstock, 1/87th may not be that hard to do. The hub flanges would be the only challenge - those little b***rds are already electron-microscope material at 1/60th scale - at 1/87th they could disappear altogether!

Try it out though - & let us know the results!


Top
 Profile  
 
 Post subject:
PostPosted: Fri May 09, 2008 8:46 pm 
Offline
Botbuster Master
User avatar

Joined: Thu Apr 28, 2005 5:08 pm
Posts: 2345
Location: HARTSHORNE, OKLA.
ohh yeah...by the way...you must have really good camera.....those are very crisp and sharp pics.... :D

_________________
Laterz
Possm_23
Never say anything you wouldnt think out loud!
Take your time leavin.....but hurry back!!!!
Every tub has to sit on its own bottom!!!!


Top
 Profile  
 
 Post subject:
PostPosted: Sat May 10, 2008 1:18 am 
Offline
Paper Model Overlord
User avatar

Joined: Fri Oct 06, 2006 1:15 pm
Posts: 528
Location: Alameda CA
John Dell wrote:
WOW! I'm going to try that on my B-24.

One side attribute of this design is that building a feathered prop is easily accomplished by simply gluing the blades to the spider at 90 degrees of pitch. You might try building one of the B-24's props feathered, and photoshopping burnt oil stains on the nacelle aft of the cowl flaps to simulate an engine smashed by enemy fire.


Top
 Profile  
 
 Post subject:
PostPosted: Mon May 12, 2008 11:20 pm 
Offline
FG Origami Master

Joined: Wed Jun 13, 2007 4:16 pm
Posts: 360
Location: Montana USA
SWEET! i'll try that when i take in my B17 project. thanks airportkid!

_________________
I'm not wierd! I'm normality impaired!


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 12 posts ] 

All times are UTC - 7 hours


Who is online

Users browsing this forum: No registered users and 5 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group