Author Topic: Grumman Bearcat  (Read 325 times)

0 Members and 1 Guest are viewing this topic.

lastvautour

  • Administrator
  • Hero Member
  • *****
  • Posts: 5905
Re: Grumman Bearcat
« Reply #15 on: August 29, 2017, 07:16:59 AM »
My biggest allies are my Mk i eyeballs. I rough shape the blocks and after that is take away a bit at a time until it looks like what I want. I was never any good at using contour templates.  I think of my Bearcat every day but still have no time to devote to it. I made four benches over the week and have them up. Now the job is to organize. I also took out my scroll saw but now need a method to better control dust. My approach to hook up our unused central vac did not go well, so back to the drawing board.

Lou

Looking forward to you progress shots.

FlyingS

  • Moderator
  • Full Member
  • *****
  • Posts: 31
Re: Grumman Bearcat
« Reply #16 on: August 30, 2017, 05:59:23 PM »
This was my first one I used templates. 20 years ago thats how they developed the air frames (at least on helicopters) My  first two models were by eye. I do have a good eye for symmetry also. The bear cat has some interesting shapes. As usual life gets in the way of my hobby, but I try to get a little in each day. I will post some pictures when I get more detail finished.

Model Maker

  • Full Member
  • ***
  • Posts: 183
Re: Grumman Bearcat
« Reply #17 on: September 03, 2017, 09:07:13 AM »
I too use templates as I don't have an eagle eye. Normally I'll import and size a plan into Turbocad which is a mid level CAD program. After than I'll create a layer for the elevations and sections in order to create the various templates. It's a little time consuming, but it also allows me to check some of the plan cross sections which are occasionally off scale potentially due to previous scanning and photo copying.

lastvautour

  • Administrator
  • Hero Member
  • *****
  • Posts: 5905
Re: Grumman Bearcat
« Reply #18 on: September 03, 2017, 11:17:24 AM »
So true. What ever works!

Lou

FlyingS

  • Moderator
  • Full Member
  • *****
  • Posts: 31
Re: Grumman Bearcat
« Reply #19 on: September 10, 2017, 04:01:32 AM »
Here is the progress so far on my Bearcat.
Lessons learned:
When I did chip carving I started at one end and worked my way to the end…finished. But I tried that with the bearcat and soon learned I was running into a speed bump with the rest of the fuselage. I took Lou’s advice and roughed out the whole fuselage first.
I made templates but mainly use then to check the radiuses. The profile of this airframe transitions from a circle at the nose and transitions into an egg shape at he canopy and tappers down to the tail. I found I was getting too focused on fitting the templates instead of eyeballing the whole fuselage as I went along. For me I find using the templates more as a “radius gage” because most photos don't seem to show the transitions in the shape of the airframe.
After I bandsaws the top and side profile I finished then to kind of give me a gage for the finished size. Not sure if that was a good idea? next time I’m going to leave a little extra so I can finish sanding the whole fuselage together.
Next thing to tackle is shaping the canopy bubble. ( First one like this one for me)

lastvautour

  • Administrator
  • Hero Member
  • *****
  • Posts: 5905
Re: Grumman Bearcat
« Reply #20 on: September 10, 2017, 11:19:50 AM »

FlyingS

  • Moderator
  • Full Member
  • *****
  • Posts: 31
Re: Grumman Bearcat
« Reply #21 on: September 18, 2017, 09:09:57 AM »
Hope to have some new pictures of progress soon.
I have a question...the Bearcat has a 4 blade prop and I am trying to decide between the plastic disk or carve the blades from wood. If I go with the wood would you carve the blades from one piece or individual blades and glue them to the hub? It seems to me the blades wouldn't have much of a cross section for the glue to hold the blade very well?
This model has been a challenge for me therefore taking me more time than I thought, But I have been picking up got pointers for my next model.
Harv

johnnytodd

  • Full Member
  • ***
  • Posts: 61
Re: Grumman Bearcat
« Reply #22 on: September 18, 2017, 12:40:42 PM »
Harv,

I carve my propellor blades individually and then glue to the hub (I file small notches into the hub at about a 45 degree angle).  When the glue dries the prop is plenty strong.

John

FlyingS

  • Moderator
  • Full Member
  • *****
  • Posts: 31
Re: Grumman Bearcat
« Reply #23 on: September 18, 2017, 01:18:43 PM »
Brilliant, I should have thought of that. haha.
Thanks
Harv ::)

johnnytodd

  • Full Member
  • ***
  • Posts: 61
Re: Grumman Bearcat
« Reply #24 on: September 18, 2017, 04:09:28 PM »
In the past I cut 1/32nd flat basswood or plywood as simple prop blades.... but lately I use something thicker, then file/sand/shape blade into more accurate screw shape

Model Maker

  • Full Member
  • ***
  • Posts: 183
Re: Grumman Bearcat
« Reply #25 on: September 18, 2017, 09:02:49 PM »
Hi Harv;

I also carve the blades individually and attach them to the hub. But I leave a round plug at the hub end of the blade which is inserted into a hole drilled in the hub. I put together a short document on this approach on the link below. It's listed under the "Tips & Techniques" section of the main board.  Select Construction Techniques/Propeller Hubs and Blades. Or you can click on the link below. There's a PDF document under the start of the thread which outlines the approach.

http://smm.solidmodelmemories.net/SMF/index.php?topic=1372.0

This method is very strong for 1/32 scale. I cannot comment on any other scales at this time.

-ken
« Last Edit: September 18, 2017, 09:04:49 PM by Model Maker »

lastvautour

  • Administrator
  • Hero Member
  • *****
  • Posts: 5905
Re: Grumman Bearcat
« Reply #26 on: September 19, 2017, 08:35:08 AM »
Examples of my propellers. I can't believe I never did a tutorial on this nor did I describe it in other posts.

Bollingbrook

WACO Cabin Biplane

Hudson


I make my propeller with a hub, drilled to accept  a stub to which I will accept a hollow blade shaft. It does not mater how many blades. I will search some more, I am sure I must have shown my method. Now to find it.

Lou

lastvautour

  • Administrator
  • Hero Member
  • *****
  • Posts: 5905
Re: Grumman Bearcat
« Reply #27 on: September 19, 2017, 08:39:29 AM »
Found this but it does not show the construction of the hub.

http://smm.solidmodelmemories.net/SMF/index.php?topic=1013.0

Lou

FlyingS

  • Moderator
  • Full Member
  • *****
  • Posts: 31
Re: Grumman Bearcat
« Reply #28 on: September 20, 2017, 05:52:49 AM »
Thanks for the great information. I have learned so much from you guys and has helped me improve my carving methods. Lou, I forgot to mention that I have had those wooden clamps for years and never used them now I find they make a great vise/holding clamps.
Here is the latest on my Bearcat:
Need to finish sanding profile of nose and cockpit.
Finish shaping thickness of wing and finish sanding. (Wing air inlets are giving me a challenge  :P)
Finish carving the tail section.

lastvautour

  • Administrator
  • Hero Member
  • *****
  • Posts: 5905
Re: Grumman Bearcat
« Reply #29 on: September 20, 2017, 09:15:57 AM »
You are doing exceedingly well for a novice builder.

Lou