LocostUSA.com

Learning how to build Lotus Seven replicas...together!
It is currently January 25, 2021, 2:19 am

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 46 posts ]  Go to page 1, 2, 3, 4  Next
Author Message
PostPosted: July 5, 2020, 7:38 pm 
Offline

Joined: September 20, 2011, 7:21 am
Posts: 107
https://www.youtube.com/watch?v=QESyuZVBkJ8&t=55s

look likes it is very easy to make :shock:


Top
 Profile  
Reply with quote  
PostPosted: July 6, 2020, 1:31 am 
Offline
User avatar

Joined: November 11, 2013, 4:47 am
Posts: 1354
Location: No. Nevada
What I saw in the video I would say no, mock-up only.

Lots of discussion in this oldish thread,
viewtopic.php?f=39&t=18798&hilit=carbon+fiber

But I still plan to do a plywood/foam main structure for my Tatum-13B Suzuki build.
Major difference is in the use of foam only as a filler for the wood structure.
Engine cradle will be tube steel attached to the rear bulkhead.

_________________
If I must be a one-man PC free zone, so be it!


Top
 Profile  
Reply with quote  
PostPosted: July 6, 2020, 1:59 am 
Offline
User avatar

Joined: December 17, 2010, 1:24 pm
Posts: 1551
Location: Gainesville, Mo.
It would probably take some engineering, but could be done! Jim Hall's Chaparral 2 race cars were a fiberglass monocoque, and there are a lot of foam and F/G airplanes flying around now!

_________________
Mike - Read my story at http://twinlakesseven.blogspot.com/


Top
 Profile  
Reply with quote  
PostPosted: July 6, 2020, 7:18 am 
Offline
User avatar

Joined: June 20, 2019, 12:34 pm
Posts: 301
My ex-brother-in law had a company that built composite experiential planes for decades (including military drones)! It can be done, but you really need to know what you're doing. It would take some serious engineering

Thom


Top
 Profile  
Reply with quote  
PostPosted: July 6, 2020, 7:49 am 
Offline

Joined: September 20, 2011, 7:21 am
Posts: 107
BostonWill wrote:
My ex-brother-in law had a company that built composite experiential planes for decades (including military drones)! It can be done, but you really need to know what you're doing. It would take some serious engineering

Thom

if it really work, there are many things can do

e.g. 3d print foam core parts


Top
 Profile  
Reply with quote  
PostPosted: July 6, 2020, 11:47 am 
Offline
User avatar

Joined: December 17, 2010, 1:24 pm
Posts: 1551
Location: Gainesville, Mo.
The experimental aircraft arena is probably your best bet for advice and inspiration! One of the best books that I know of is "Moldless Composite Sandwich Aircraft Construction" by Burt Rutan. There are others out there but Rutan is one of the pioneers with an impressive track record!

_________________
Mike - Read my story at http://twinlakesseven.blogspot.com/


Top
 Profile  
Reply with quote  
PostPosted: July 6, 2020, 6:55 pm 
Offline
User avatar

Joined: December 24, 2007, 5:11 am
Posts: 1178
Location: Seattle area
I think all F1 and Indy cars are carbon fiber tubs these days. The carbon is stronger than GRP for a given thickness ut for stress points you can make the GRP thicker.

Often thought about this but I really don't know enough go any further than wondering.

_________________
Larry in Seattle


Top
 Profile  
Reply with quote  
PostPosted: July 6, 2020, 7:10 pm 
Offline

Joined: September 20, 2011, 7:21 am
Posts: 107
benny_toe wrote:
I think all F1 and Indy cars are carbon fiber tubs these days. The carbon is stronger than GRP for a given thickness ut for stress points you can make the GRP thicker.

Often thought about this but I really don't know enough go any further than wondering.

carbon is more expensive than GRP :BH:


Top
 Profile  
Reply with quote  
PostPosted: July 6, 2020, 7:18 pm 
Offline

Joined: September 20, 2011, 7:21 am
Posts: 107
ngpmike wrote:
The experimental aircraft arena is probably your best bet for advice and inspiration! One of the best books that I know of is "Moldless Composite Sandwich Aircraft Construction" by Burt Rutan. There are others out there but Rutan is one of the pioneers with an impressive track record!

it really quiet strong

https://www.youtube.com/watch?v=biZ2Sl63nr0


Top
 Profile  
Reply with quote  
PostPosted: July 6, 2020, 11:24 pm 
Offline
User avatar

Joined: April 19, 2018, 2:02 am
Posts: 204
The BEC book talks about aluminum honeycomb construction and bonding stuff together. I wouldn't trust my skills on that. Welding steel is relatively easy and reliable.

But that foam build video is very cool. Some serious skills that guy has. I may do a seat build thread for my BEC, I CNCed a foam mold for that, albeit one sided. But you could "fairly easily" CNC both sides to make a foam core. You'd need a BIG 3d printer to print part cores, but maybe it could be done.

_________________
"It ain’t what you don’t know that gets you into trouble, it’s what you know for sure that just ain’t so."


Top
 Profile  
Reply with quote  
PostPosted: July 7, 2020, 3:32 am 
Online
User avatar

Joined: April 26, 2008, 6:06 pm
Posts: 3118
Location: Under the weather. (Seattle)
That partially depends how you define 'enough strength':
Enough strength to survive the first drive? Easy.
Enough strength to survive 10's or 100's of thousands of miles of street and/or track abuse? Considerably harder.
Enough strength to survive an at-speed crash? Even harder yet.

There is a reasonably large body of knowledge regarding the strength, fatigue resistance, and survivability of welded steel tube car chassis. There is not for foam core fiberglass car chassis. Airplanes tend to be better shaped for composite use than most cars are.

Much like an aluminum monocoque, I'm not saying it can't be done to an acceptable (or even superior) level...Just that the standard of proof before I'd trust my own life to riding in one at highway (or greater) speeds would be much higher than for a tried and true steel tube frame.

_________________
-Justin

Also follow my build on blogspot, tumblr, or instagram and twitter (GarageOdyssey)


Top
 Profile  
Reply with quote  
PostPosted: July 7, 2020, 12:06 pm 
Offline
Always Moore!
User avatar

Joined: November 9, 2007, 3:40 pm
Posts: 4011
Location: Pittsburgh, PA
"Is it strong enough?" - the simple answer is yes.

Its strength and elongation properties put it at a disadvantage to carbon fiber since you will need more of it to get the strength but the extra stiffness will hurt its ability to absorb energy in an impact without failing (think brittle vs. ductile materials).

The design requirements to successfully build a composite monocoque are not difficult but definitely a few levels above designing a steel space frame. You need to worry about ply orientation, the number of plies, and how you handle things like lapjoints and high stress areas where suspension components, seats, seatbelts, and rollbars attach.

_________________
-Andrew
Build Log
Youtube


Top
 Profile  
Reply with quote  
PostPosted: July 7, 2020, 3:40 pm 
Offline
User avatar

Joined: November 11, 2013, 4:47 am
Posts: 1354
Location: No. Nevada
a.moore wrote:
"Is it strong enough?" - the simple answer is yes.

Its strength and elongation properties put it at a disadvantage to carbon fiber since you will need more of it to get the strength but the extra stiffness will hurt its ability to absorb energy in an impact without failing (think brittle vs. ductile materials).

The design requirements to successfully build a composite monocoque are not difficult but definitely a few levels above designing a steel space frame. You need to worry about ply orientation, the number of plies, and how you handle things like lapjoints and high stress areas where suspension components, seats, seatbelts, and rollbars attach.


Yet, the plywood Marcos 1600's were remarkably simple and more rigid than the space-frame design that followed.
Basic design criteria remains the same, create boxes and triangulation as much as possible.
Foam core can be useful, but so can a simple expanded cardboard spacer.
My Tatum build is still fairly far down the list but I have done a few very basic chassis sketches.
I will have to do them again as Paper & Pencil 1.0 does not post well. :wink:

_________________
If I must be a one-man PC free zone, so be it!


Top
 Profile  
Reply with quote  
PostPosted: July 8, 2020, 8:52 am 
Offline

Joined: September 20, 2011, 7:21 am
Posts: 107
RichardSIA wrote:
a.moore wrote:
"Is it strong enough?" - the simple answer is yes.

Its strength and elongation properties put it at a disadvantage to carbon fiber since you will need more of it to get the strength but the extra stiffness will hurt its ability to absorb energy in an impact without failing (think brittle vs. ductile materials).

The design requirements to successfully build a composite monocoque are not difficult but definitely a few levels above designing a steel space frame. You need to worry about ply orientation, the number of plies, and how you handle things like lapjoints and high stress areas where suspension components, seats, seatbelts, and rollbars attach.


Yet, the plywood Marcos 1600's were remarkably simple and more rigid than the space-frame design that followed.
Basic design criteria remains the same, create boxes and triangulation as much as possible.
Foam core can be useful, but so can a simple expanded cardboard spacer.
My Tatum build is still fairly far down the list but I have done a few very basic chassis sketches.
I will have to do them again as Paper & Pencil 1.0 does not post well. :wink:


is marcos 1600 mean this?
https://www.google.com/search?q=Marcos+ ... HK707HK707


Top
 Profile  
Reply with quote  
PostPosted: July 8, 2020, 12:53 pm 
Offline
User avatar

Joined: November 11, 2013, 4:47 am
Posts: 1354
Location: No. Nevada
Yes, my old one is probably on there somewhere.
The main body did become the final chassis member.

_________________
If I must be a one-man PC free zone, so be it!


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 46 posts ]  Go to page 1, 2, 3, 4  Next

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 4 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:  
POWERED_BY