4*60 Cowl
08-29-2005, 04:54 PM
#1
Senior Member
Thread Starter
Join Date: Jun 2005
Location: San Antonio,
TX
Posts: 165
Likes: 0
Received 0 Likes
on
0 Posts
4*60 Cowl
Does anyone have a picture of a 4*60 with the Fiberglass Specialties cowl or the Stan's TT82 cowl?
I am trying to decide between these or scratch building my own balsa cowl.
Thanks,
Patrick
I am trying to decide between these or scratch building my own balsa cowl.
Thanks,
Patrick
08-30-2005, 07:48 AM
#2
Member
Join Date: Oct 2004
Location: Garden City,
MI
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
RE: 4*60 Cowl
I vote for the balsa cowl.
I've built two. One on a 4*40, and a second on a Hog Bipe. I've found it to be very easy to do, and it looks great.
I've attached a picture of the 4* cowl before covering.
I've built two. One on a 4*40, and a second on a Hog Bipe. I've found it to be very easy to do, and it looks great.
I've attached a picture of the 4* cowl before covering.
08-31-2005, 08:34 PM
#3
Senior Member
Thread Starter
Join Date: Jun 2005
Location: San Antonio,
TX
Posts: 165
Likes: 0
Received 0 Likes
on
0 Posts
RE: 4*60 Cowl
Yeah, I think I am going to go the balsa-build-it-myself route. If for no other reason than the building experience.
My only concerns are how to make it detachable and access the engine.
As far as the detachable part, I was thinking of cutting 4 rectangles out of light ply, setting some blind nuts in them and epoxying them to the firewall at the four corners mounting hole facing the sides. Once dry, I can mount 4 light play rectangles to these using screws and then attach the light ply nose ring with balsa between it and these mounts. Fill it all in and carve it to shape. Good plan?
Do I need to glass it for strength after it is shaped? I am concerned that I won't be able to get the glass down smooth enough. I thought about glassing it on the inside instead so that it won't matter as much.
As far as being able to get it off over the engine, I guess I just need to make sure that I leave enough room with the engine cutouts to be able to jockey it around.
Patrick
BTW, I will be running a ST G90 with a Dave Brown 90FS mount on this 4*60.
My only concerns are how to make it detachable and access the engine.
As far as the detachable part, I was thinking of cutting 4 rectangles out of light ply, setting some blind nuts in them and epoxying them to the firewall at the four corners mounting hole facing the sides. Once dry, I can mount 4 light play rectangles to these using screws and then attach the light ply nose ring with balsa between it and these mounts. Fill it all in and carve it to shape. Good plan?
Do I need to glass it for strength after it is shaped? I am concerned that I won't be able to get the glass down smooth enough. I thought about glassing it on the inside instead so that it won't matter as much.
As far as being able to get it off over the engine, I guess I just need to make sure that I leave enough room with the engine cutouts to be able to jockey it around.
Patrick
BTW, I will be running a ST G90 with a Dave Brown 90FS mount on this 4*60.
08-31-2005, 11:08 PM
#4
Senior Member
Join Date: Feb 2004
Location: Gilbert,
AZ
Posts: 518
Likes: 0
Received 0 Likes
on
0 Posts
RE: 4*60 Cowl
I just made a fiberglass cowl for one of my planes and it turn out great! It was pretty easy, didn't take long and now I have all of the stuff to build another one if needed. I know that this sounds like a lot of work, but I was using it as a test for a new warbird I am thinking of building. The color scheme I want to do on it is from a latter model and the cowl will have to be made.
Here are the steps:
1) Fit your engine and install the spinner.
2) Tape on the nose ring with 1/16" spacer and position correctly centering on the spinner.
3) Using balsa sticks and Elmer's white glue (not very strong) glue a minimum to two sticks from the firewall to the nose ring to hold it in place. Make sure that you can remove the engine (you might not want to use the four mount screws on the engine mount just two.
4) Remove the engine which will leave the nose ring attached to the balsa sticks in the right position.
5) Use Dry Foam (this is the green foam that they use for silk flowers, available at any art store like Michaels) and with a razor saw cut the blocks so that they will fit between the nose ring and the firewall. They should hang over quite a bit because the form easy.
6) Glue the dry foam blocks against the firewall and the nose ring and let dry.
7) Form the shape of the cowl with 150 sand paper (be careful as this foam is really soft and will come off quick).
8) Once formed, place a band of 1" blue masking tape around the fuselage behind the firewall (this is to protect the balsa).
9) Paint the foam, nose ring and about 1/2 the width of the masking tape with Gloss Modge Podge (also available from art store) which is a water based sealant and glue or you can use PVA glue. Let dry 30 minutes and apply a second coat.
10) After it is fully dry, then cover the entire cowl with spackle and sand smoth (use 220 paper).
11) After smooth, another coat of Modge Podge and let dry.
12) Now the fun stuff! Find a Box or cut one so that the cowl will fit in it with atleast 1" around the outside.
13) Fill in the hole in the nose ring, use a small block of left over dry foam, don't worry about sealing, leave about 1" protruding from the center of the ring, this will be a base for the next step.
14) Using your fingers, smear on a thin coat of Johnson paste wax or Turtle Wax or Carnuba Car wax on the cowl including the masking tape.
15) Place the nose of the aircraft into the box with the nose ring block against the bottom and pour in Plaster of Paris up to the middle of the masking tape. The plaster will set in about 10-20 minutes.
16) When set, wiggle the airplane free. Don't worry if the foam and nose ring break off. Presto, a plaster mold!
17) When the plaster is fully dry (about 1-2 hours), smear the inside of the mold with the was again.
18) Use rubber or vinyl gloves and squirt onto your fingers silicone caulk and smear it into the mold. Make sure that it covers completely. Do this with plenty of ventilation because its like snorting vinegar.
19) Allow this to set for a minimum of 16 hours. Then pull it free, it will peel right out.
20) Now for the fiber glass. For a cowl, you want to use fiber glass mate. Use the stuff from home depot or an auto body shop. Cut it into two inch strips the length of cowl plus two inches. You're going to lay up the fiber glass strips starting from the nose ring over the edge of the form. You will need enough strips to lay up three layers so for this plane probably 2" x 8" x (12 to 15 strips).
21) Wax the inside of the mold again.
21) For this project I actually like to use fiberglass resin (LHS or Home Depot, auto shop, checker...). Mix up with activator and about 1/3 micro ballons. Using a cheep bristle brush. Apply the strips around with minimal overlap. Paint resin in, next lay - cover the seams of the first, paint resin in, repeat with last layer. Make sure you resin all the way up and over the edge of the mold and lay fiber glass over the edge.
22) Now take your silicone form and place inside the fiber glass. This is were you would vaccuum form but I don't have one, so fill inside of mold with wet play sand and beat down into the form.
23) Allow at least 3 hours of setup. Fiberglass will still be just a little wobbly, and remove from the mold.
24) Allow at least 12 hours of setup outside of the mold. Sand with 80 - 150 paper until smooth (should be pretty smooth). You can then fill with body putty or glaze.
25) Sand with 220, then 320, then 400. Cut along line created by the masking tape. Prime, paint and your done.
I know it sounds like a lot of work, but I only invested about two hours of actual work and most of it was forming the orignal cowl. I now have a mold that I can do another with in just about an hours worth of work. Much more durrable than just balsa.
Anyway, some of this technique was barrowed from Caffeine man's web site, http://www.airfieldmodels.com. Got to give him the credit, an awsome site!
Here are the steps:
1) Fit your engine and install the spinner.
2) Tape on the nose ring with 1/16" spacer and position correctly centering on the spinner.
3) Using balsa sticks and Elmer's white glue (not very strong) glue a minimum to two sticks from the firewall to the nose ring to hold it in place. Make sure that you can remove the engine (you might not want to use the four mount screws on the engine mount just two.
4) Remove the engine which will leave the nose ring attached to the balsa sticks in the right position.
5) Use Dry Foam (this is the green foam that they use for silk flowers, available at any art store like Michaels) and with a razor saw cut the blocks so that they will fit between the nose ring and the firewall. They should hang over quite a bit because the form easy.
6) Glue the dry foam blocks against the firewall and the nose ring and let dry.
7) Form the shape of the cowl with 150 sand paper (be careful as this foam is really soft and will come off quick).
8) Once formed, place a band of 1" blue masking tape around the fuselage behind the firewall (this is to protect the balsa).
9) Paint the foam, nose ring and about 1/2 the width of the masking tape with Gloss Modge Podge (also available from art store) which is a water based sealant and glue or you can use PVA glue. Let dry 30 minutes and apply a second coat.
10) After it is fully dry, then cover the entire cowl with spackle and sand smoth (use 220 paper).
11) After smooth, another coat of Modge Podge and let dry.
12) Now the fun stuff! Find a Box or cut one so that the cowl will fit in it with atleast 1" around the outside.
13) Fill in the hole in the nose ring, use a small block of left over dry foam, don't worry about sealing, leave about 1" protruding from the center of the ring, this will be a base for the next step.
14) Using your fingers, smear on a thin coat of Johnson paste wax or Turtle Wax or Carnuba Car wax on the cowl including the masking tape.
15) Place the nose of the aircraft into the box with the nose ring block against the bottom and pour in Plaster of Paris up to the middle of the masking tape. The plaster will set in about 10-20 minutes.
16) When set, wiggle the airplane free. Don't worry if the foam and nose ring break off. Presto, a plaster mold!
17) When the plaster is fully dry (about 1-2 hours), smear the inside of the mold with the was again.
18) Use rubber or vinyl gloves and squirt onto your fingers silicone caulk and smear it into the mold. Make sure that it covers completely. Do this with plenty of ventilation because its like snorting vinegar.
19) Allow this to set for a minimum of 16 hours. Then pull it free, it will peel right out.
20) Now for the fiber glass. For a cowl, you want to use fiber glass mate. Use the stuff from home depot or an auto body shop. Cut it into two inch strips the length of cowl plus two inches. You're going to lay up the fiber glass strips starting from the nose ring over the edge of the form. You will need enough strips to lay up three layers so for this plane probably 2" x 8" x (12 to 15 strips).
21) Wax the inside of the mold again.
21) For this project I actually like to use fiberglass resin (LHS or Home Depot, auto shop, checker...). Mix up with activator and about 1/3 micro ballons. Using a cheep bristle brush. Apply the strips around with minimal overlap. Paint resin in, next lay - cover the seams of the first, paint resin in, repeat with last layer. Make sure you resin all the way up and over the edge of the mold and lay fiber glass over the edge.
22) Now take your silicone form and place inside the fiber glass. This is were you would vaccuum form but I don't have one, so fill inside of mold with wet play sand and beat down into the form.
23) Allow at least 3 hours of setup. Fiberglass will still be just a little wobbly, and remove from the mold.
24) Allow at least 12 hours of setup outside of the mold. Sand with 80 - 150 paper until smooth (should be pretty smooth). You can then fill with body putty or glaze.
25) Sand with 220, then 320, then 400. Cut along line created by the masking tape. Prime, paint and your done.
I know it sounds like a lot of work, but I only invested about two hours of actual work and most of it was forming the orignal cowl. I now have a mold that I can do another with in just about an hours worth of work. Much more durrable than just balsa.
Anyway, some of this technique was barrowed from Caffeine man's web site, http://www.airfieldmodels.com. Got to give him the credit, an awsome site!
08-31-2005, 11:27 PM
#5
Senior Member
Thread Starter
Join Date: Jun 2005
Location: San Antonio,
TX
Posts: 165
Likes: 0
Received 0 Likes
on
0 Posts
RE: 4*60 Cowl
Well dang! You have made me change my mind again!
This is exactly what I wanted to do... my own fiberglass cowl, but the articles I have seen skipped the mold step. I have some experience about 15 years ago making fiberglass molds for a cultured marble shop, and I remember how hard it was to get imperfections out of the finished product if you didn't have your plug perfect. So, there was no way I was going to try and smooth out the non-plug side of a fiberglass cowl with sandpaper. I just hadn't thought of or seen a good way to make the mold.
Thank You!!! When I get to this part of the build I will post pictures if I am successful enough not to be embarased about it, hehe
.
Patrick
This is exactly what I wanted to do... my own fiberglass cowl, but the articles I have seen skipped the mold step. I have some experience about 15 years ago making fiberglass molds for a cultured marble shop, and I remember how hard it was to get imperfections out of the finished product if you didn't have your plug perfect. So, there was no way I was going to try and smooth out the non-plug side of a fiberglass cowl with sandpaper. I just hadn't thought of or seen a good way to make the mold.
Thank You!!! When I get to this part of the build I will post pictures if I am successful enough not to be embarased about it, hehe
.Patrick
