Logo
Builders' Plan Gallery  |  Hip Pocket Web Site  |  Contact Forum Admin  |  Contact Global Moderator
April 28, 2017, 02:00:42 PM *
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: Beech A-38 Grizzly (Destroyer)  (Read 1243 times)
0 Members and 1 Guest are viewing this topic.
Otakar
Bronze Member
***

Kudos: 0
Offline Offline

United States United States

Posts: 49

Topic starter


Ignore
« on: November 25, 2016, 07:05:15 AM »

Hello guys;
I am new to this website, when it comes to the chat room. This is also the first thread which I have actually started. I started talking about the A-38 on another thread but now feel like I am attempting to Hijack it. Since I do not want to do that I decided to start a new Thread about the A-38.
  This was an aircraft which not many people know about and because of the requirement of the engines for the B-29, was never produced in the quantity to make it a true wonder.
This Could have been a truly awesome bird if it would have gone into full production. But never the less, it still is a cool aircraft and I think the only aircraft with two R-3350s mounted on it and only a 67ft wingspan.
  This aircraft has never been done in a true model, that i know of. I was thinking of making one in 1/16 stick-n-tissue for display and one in 1/12 stick-n-sheeting for electric RC, 50" & 67" respectively. Since there is very little on this aircraft when it comes to drawings but quite a few photographs, I think it would still be doable. I was thinking about first doing this in CAD before I take on the actual endeavor.
   But first I would like to start a real discussion about this unusual but I think interesting subject.

Attached files Thumbnail(s):
Beech A-38 Grizzly (Destroyer)
Beech A-38 Grizzly (Destroyer)
Logged
tom arnold
Gold Member
*****

Kudos: 23
Offline Offline

United States United States

Posts: 573


Casper Wyoming



Ignore
« Reply #1 on: November 25, 2016, 11:57:15 AM »

I have had this subject on my "To Do" list for a couple of building seasons (don't we all have planes like that?) although not as RC or static but as a rubber powered scale twin of 27"-30" span. It has all the goodies for that in the big, fat, long, underslung engine nacelles with props well forward, generous stabilizer area and adequate wing area. The drawbacks are a pretty boring full-size paint scheme plus it is aluminum which shows up every teeny little boo-boo you make. Fortunately FAC rules allow "coulda-been" paint schemes. You are right that there is precious little in the way of 3 views and practically no bulkhead cross sections which is both good and bad. Bad in the fact that it won't satisfy the purist in shape but good in that anything a modeller comes up with that looks close is fine precision.

My plan in building a rubber scale twin is to carve and sand a half shell of the fuselage (and nacelles) from blue foam using what info I can transpose off the 3 view and referring to the very good photos that are on the internet. This is not difficult and you can get very very close to the actual shape. I have experimented with this on subjects that I knew the cross sections on as a check. I was a little amazed at how close my amateur sculpting came, really. An aircraft fuselage is always a smooth curve between known points. The Grizzly fuselage is basically a rounded rectangle and perfect for this method. After smoothing up the half shell with fine sandpaper, I'd mark off on a centerline where the bulkheads should go. Then a careful 90 degree cut with a very sharp knife at each location would give me the bulkheads I could trace to paper. That would be my plan if I wanted sheet bulkhead construction or I'd go with a Lost Foam approach and use wet reed and a foam internal jig.

The whole CAD approach seems like a lot of work for no more precision than your eyeball as the above. But it all depends if a guy likes to use computer and is comfortable with CAD. Great airplane, though, and looking forward to what you come up with.
Logged
Otakar
Bronze Member
***

Kudos: 0
Offline Offline

United States United States

Posts: 49

Topic starter


Ignore
« Reply #2 on: November 25, 2016, 12:43:54 PM »

Why didn't I think of that! The foam method would be perfect for the 1/12 RC variant. I might even be able to find someone who could 3-D Scan it and give me the proportions for the bulkheads on the 1/16 version (MUST be stick-N-tissue)(it is just so classically beautiful. From some rudimentary measurements, the fuselage would be about 6"" wide in the widest beam in the 1/12 scale. with the measurements i could take it looks like it was about 60" wide in the beam. That means that laminating three sheets of 2" blue-foam for the full width or a 1" + 2" would give a half Fuse.The What-If scheme I would like to do is this one.
 
Attached files Thumbnail(s):
Re: Beech A-38 Grizzly (Destroyer)
« Last Edit: November 25, 2016, 01:03:10 PM by Otakar » Logged
strat-o
Silver Member
****

Kudos: 5
Offline Offline

United States United States

Posts: 163



Ignore
« Reply #3 on: November 25, 2016, 01:39:58 PM »

A profile gauge or contour gauge would allow you to get the shape transferred from the foam form to paper without being destructive.  This, at least, allows you to change your mind later.

Logged
Otakar
Bronze Member
***

Kudos: 0
Offline Offline

United States United States

Posts: 49

Topic starter


Ignore
« Reply #4 on: November 25, 2016, 03:16:48 PM »

in which case, I would actually be better off to make it smaller. Like 1:24 scale. It would make the fuse about 23" long and about 2.5" wide. This would make it much easier to carve and also measure because it can be measured with a 6" wire gauge which is much finer in detail than the larger plastic gauges. It can also be carved out of just two laminated B-foam sheets of 2" each. The best way to do this is to laminate three sheets of brown paper together with PVA and than draw the outline out on that and than glue the foam on each side. Once the fuse is finished than it can be submerged in water and the PVA with paper will release and split the two halves apart. I will have to see if I can find some proto-foam instead of using blue-foam. It carvs much better and is chemical impervious. It can be Glassed, doped, or covered with anything including Bondo.
Logged
tom arnold
Gold Member
*****

Kudos: 23
Offline Offline

United States United States

Posts: 573


Casper Wyoming



Ignore
« Reply #5 on: February 16, 2017, 05:51:47 PM »

Otakar, how is this project coming along?
Logged
p40qmilj
Platinum Member
******

Kudos: 24
Offline Offline

Canada Canada

Posts: 1,409


love that P40Q



Ignore
« Reply #6 on: February 17, 2017, 07:47:01 AM »

 Grin  check wings/airpower issues  they did the grizzly between 2001 and 7 when they ceased pub. Sad Sad Sad Sad Sad Sad Sad

jim Grin
Logged
Crabby
Platinum Member
******

Kudos: 57
Offline Offline

United States United States

Posts: 1,234


I never met a modeler I didn't like



Ignore
« Reply #7 on: February 17, 2017, 10:44:49 AM »

If one was ever on the fence over which to build, the A-26 Invader, or a Beech Model 18, this would be a good solution looks-wise anyway...
Logged

The Threadkiller!
Bell Models
Silver Member
****

Kudos: 9
Offline Offline

United States United States

Posts: 170



Ignore
« Reply #8 on: February 17, 2017, 12:20:47 PM »

Google Beechcraft A-38, plenty of drawings there.

John Bell
Logged
NavyAD1
Bronze Member
***

Kudos: 1
Offline Offline

United States United States

Posts: 31




Ignore
« Reply #9 on: February 17, 2017, 01:03:01 PM »

Try this:  http://www.militaryfactory.com/imageviewer/ac/gallery-ac.asp?aircraft_id=706
Logged
Otakar
Bronze Member
***

Kudos: 0
Offline Offline

United States United States

Posts: 49

Topic starter


Ignore
« Reply #10 on: February 17, 2017, 06:33:09 PM »

There are plenty of photos available but the drawings are quite scarce. The ones that are available are spartan to say the least. I think that the only way I will be able to do this project at all is to extrapolate from the photos. I started to do a basic drawing in CAD and will go from there.
Logged
Bell Models
Silver Member
****

Kudos: 9
Offline Offline

United States United States

Posts: 170



Ignore
« Reply #11 on: February 18, 2017, 12:40:03 AM »

There are two good plans off Google.  Have attached one of them. Using this one can save you a lot of time. Just get it enlarged.

John Bell
Attached files Thumbnail(s):
Re: Beech A-38 Grizzly (Destroyer)
Logged
tom arnold
Gold Member
*****

Kudos: 23
Offline Offline

United States United States

Posts: 573


Casper Wyoming



Ignore
« Reply #12 on: February 21, 2017, 11:46:14 AM »

And another for comparison, although John's is best with the dimensions. John, is this the second one you mentioned?
Attached files Thumbnail(s):
Re: Beech A-38 Grizzly (Destroyer)
Logged
Bell Models
Silver Member
****

Kudos: 9
Offline Offline

United States United States

Posts: 170



Ignore
« Reply #13 on: February 21, 2017, 12:01:55 PM »

Yes. This is the second one.

John
Logged
Otakar
Bronze Member
***

Kudos: 0
Offline Offline

United States United States

Posts: 49

Topic starter


Ignore
« Reply #14 on: February 21, 2017, 12:06:34 PM »

Yes I found both of those and have had them in my files for a while. We are still guessing at the cross sections on this. I guess I might be able to extrapolate from the C-45 in cross-sectional shape. I can also try to get hold of Beech and see if they still might have anything in their archives. I have already taken these and converted them to DXF for the template drawing.
Logged
Sky9pilot
Titanium Member
*******

Kudos: 45
Offline Offline

United States United States

Posts: 2,612


WWW

Ignore
« Reply #15 on: February 21, 2017, 05:07:19 PM »

Got inspired with your original post and pictures.  I've loved this plane for a long time as well.  I got those 3-views and the pictures on the web and put together this plan.  I haven't built from it yet so it's untried.  You can find it posted here: Click Here

Sky9pilot
Logged

Best Regards,
Sky9pilot
    "If God is your Co-pilot, consider switching seats!" 
http://www.stickandtissue.com/cgi-bin/yabb2/YaBB.pl
strat-o
Silver Member
****

Kudos: 5
Offline Offline

United States United States

Posts: 163



Ignore
« Reply #16 on: February 21, 2017, 10:24:30 PM »

Tom, I think you nailed it. Good job

Marlin
Logged
Don McLellan
Titanium Member
*******

Kudos: 46
Online Online

Canada Canada

Posts: 2,120




Ignore
« Reply #17 on: February 21, 2017, 10:40:36 PM »

Very nice plan Tom.  I've also looked at this airplane many times.

Don
Logged
Sky9pilot
Titanium Member
*******

Kudos: 45
Offline Offline

United States United States

Posts: 2,612


WWW

Ignore
« Reply #18 on: February 21, 2017, 10:42:17 PM »

Strat-o...I agree with you that's why my former is oval but looking closer to the the pictures especially this one from the upper left front quarter looks like the sides are a bit flatter.  I will admit that I used the oval tool in my CAD program for the "A" former because I didn't think the drawings were accurate there as well.  I'll look closer and see what I might come up with.
Tom/Sky9pilot

edit:  quick and dirty former "A" new shape which will require former "B" to be reshaped! Roll Eyes Shocked Grin Wink Cool
Attached files Thumbnail(s):
Re: Beech A-38 Grizzly (Destroyer)
Re: Beech A-38 Grizzly (Destroyer)
« Last Edit: February 21, 2017, 10:59:21 PM by Sky9pilot » Logged

Best Regards,
Sky9pilot
    "If God is your Co-pilot, consider switching seats!" 
http://www.stickandtissue.com/cgi-bin/yabb2/YaBB.pl
tom arnold
Gold Member
*****

Kudos: 23
Offline Offline

United States United States

Posts: 573


Casper Wyoming



Ignore
« Reply #19 on: February 21, 2017, 10:47:52 PM »

Great Grizzly plans and the same for the rest of them too. I love the twin engined U-2. Very nice work on them all.
Logged
Sky9pilot
Titanium Member
*******

Kudos: 45
Offline Offline

United States United States

Posts: 2,612


WWW

Ignore
« Reply #20 on: February 21, 2017, 11:01:41 PM »

Thanks Tom, I appreciate that!  

I'm going to build one of those U-2 with twin rubber clear props (or as close to clear as I can).   Wink Grin
The more I Look at the former I had to revise it! It's on the revised plan.
Sky9pilot
« Last Edit: February 21, 2017, 11:49:21 PM by Sky9pilot » Logged

Best Regards,
Sky9pilot
    "If God is your Co-pilot, consider switching seats!" 
http://www.stickandtissue.com/cgi-bin/yabb2/YaBB.pl
Otakar
Bronze Member
***

Kudos: 0
Offline Offline

United States United States

Posts: 49

Topic starter


Ignore
« Reply #21 on: February 22, 2017, 05:56:32 AM »

WOW, that is fantastic. Do you have that in DXF? I would love the opportunity to work on that a bit.
Logged
Sky9pilot
Titanium Member
*******

Kudos: 45
Offline Offline

United States United States

Posts: 2,612


WWW

Ignore
« Reply #22 on: February 22, 2017, 11:40:01 AM »

I've appreciated the suggestions for the plan.  I must admit that I have taken a couple "Rubber Powered Tweaks" to the drawing of this plan.  I've left the nacelles a bit wider than the scale taper towards the rear for rubber motor clearance.  I've also moved the nacelles out on the wing by 1/4" giving me room for a larger prop.  The horizontal stab has also been enlarged approximately 20%.  I think this doesn't distract too much from the scale look of the plane.  There are some small scoops and details that I left off the plan that would be added in the build process.  I realize it's not a Wylam drawing!

Strato...the top of former "H" appears to be rather flat with rounded edges in the picture.

Sky9pilot
Attached files Thumbnail(s):
Re: Beech A-38 Grizzly (Destroyer)
Logged

Best Regards,
Sky9pilot
    "If God is your Co-pilot, consider switching seats!" 
http://www.stickandtissue.com/cgi-bin/yabb2/YaBB.pl
strat-o
Silver Member
****

Kudos: 5
Offline Offline

United States United States

Posts: 163



Ignore
« Reply #23 on: February 22, 2017, 02:17:47 PM »

Quote
Strato...the top of former "H" appears to be rather flat with rounded edges in the picture.

Aha, you are right.

One thing unusual about this design (the prototype, I mean) is the elevator is full span without any break in the middle, yet it appears to be attached to the fuselage all the way to the trailing edge.  I think the consensus is that there is a wedge that is attached to the elevator that moves in and out of the fuselage. 

Marlin
Logged
Sky9pilot
Titanium Member
*******

Kudos: 45
Offline Offline

United States United States

Posts: 2,612


WWW

Ignore
« Reply #24 on: February 22, 2017, 02:47:46 PM »

If you look closely you can see sleeve that is wedge shaped that does drop into the tail cone as the elevator lowers. IMO probably for streamlining.
Tom
Attached files Thumbnail(s):
Re: Beech A-38 Grizzly (Destroyer)
Logged

Best Regards,
Sky9pilot
    "If God is your Co-pilot, consider switching seats!" 
http://www.stickandtissue.com/cgi-bin/yabb2/YaBB.pl
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!