fibreglass fuel tanks !! whats the norm and what seems to be used ??

Discussion in 'Composites' started by tunnels, Aug 29, 2015.

Help Support HomeBuiltAirplanes Forum by donating:

  1. Aug 29, 2015 #1

    tunnels

    tunnels

    tunnels

    Banned

    Joined:
    Sep 7, 2014
    Messages:
    559
    Likes Received:
    21
    Location:
    china is my home , place of work but was born in N
    I am wanting to make fibreglass fuel tanks and want to know what is normally used for planes !! shape and size with or without baffles .The placement fillers and gauge mountings also what are the acceptable ways of venting .Fuselage mounted inside or wing mounted up hi and where ??

    I'm all ways being told planes are not boats even though so many things are done the same way !!
     
  2. Aug 29, 2015 #2

    wsimpso1

    wsimpso1

    wsimpso1

    Super Moderator Staff Member

    Joined:
    Oct 19, 2003
    Messages:
    6,004
    Likes Received:
    3,260
    Location:
    Saline Michigan
    Fuel tanks can go many place, and since they can have a huge influence on CG, must be part and parcel of the configuration.

    Wings are common places for them, being as you have a volume not particularly useful for people or bags and it is on CG. The safety argument goes on and on with proponents for both wing and fuselage tanks. The argument for wing type is the fuel is away from the people in a forced landing, with a downside that a forced landing with wing tanks will spill fuel on a nasty forced landing, making it unsurvivable. The argument for fuselage type is the cockpit should be designed to be sturdy enough to protect the humans, and including the tanks with them is going to prevent tank breaching in almost all survivable wrecks.

    In composite airplanes, integral tanks are the usual way. Epoxy tolerates straight gasoline and jet fuel just fine, but ethanol loaded gasoline can cause issues with some epoxies. I coated my tanks with fluoro-silicone from Dow-Corning just in case ethanol laden fuel is unavoidable. Vinylester resin is supposed to be proof against both heat and ethanol, but there are other issues with it.

    Cores that are in the same structures as fuels must be fuel safe. Gasoline will diffuse about and melt styrene foams that are in the same chunk of structure. PVC foam cores are excellent and make sturdy parts.

    Billski
     
    JamesG likes this.
  3. Aug 29, 2015 #3

    BJC

    BJC

    BJC

    Well-Known Member HBA Supporter

    Joined:
    Oct 7, 2013
    Messages:
    9,731
    Likes Received:
    6,513
    Location:
    97FL, Florida, USA
    Billski:

    What are the other issues that you are referring to?

    Thanks,


    BJC
     
  4. Aug 29, 2015 #4

    Vision_2012

    Vision_2012

    Vision_2012

    Well-Known Member

    Joined:
    Apr 21, 2010
    Messages:
    274
    Likes Received:
    122
    Location:
    Shady Cove, OR
    Mr. Tunnels.
    Again, my advice is to buy a set of plans for a scratch built composite plane and study them.
    Or buy and read some of the books listed in the how-to file of this website.
    I'm sure there are people to answer this top post and summarize the process for you, but with a summary, what nuggets of info may be glossed over?
     
  5. Aug 29, 2015 #5

    BillM

    BillM

    BillM

    Well-Known Member

    Joined:
    Feb 23, 2013
    Messages:
    140
    Likes Received:
    26
    Location:
    Santee, Ca, USA
  6. Aug 29, 2015 #6

    wsimpso1

    wsimpso1

    wsimpso1

    Super Moderator Staff Member

    Joined:
    Oct 19, 2003
    Messages:
    6,004
    Likes Received:
    3,260
    Location:
    Saline Michigan
    Vinylester resin is reputed to have some issues with secondary bonding. I have not looked into it further than just hearing that. Perhaps we could start a thread and get details.

    Billski
     
  7. Aug 29, 2015 #7

    Dan Thomas

    Dan Thomas

    Dan Thomas

    Well-Known Member

    Joined:
    Sep 18, 2008
    Messages:
    4,872
    Likes Received:
    2,083
    I have used a fiberglaass tank, made with polyester resin, for almost 20 years with no leaks at all. It is way overbuilt and heavy, though, and repairing it would require using epoxy resin, since polyester doesn't bond well to old polyester.

    If I replaced it, I would use metal. No compound curves to it anyway.

    Dan
     
  8. Aug 29, 2015 #8

    mcrae0104

    mcrae0104

    mcrae0104

    Armchair Mafia Conspirator HBA Supporter

    Joined:
    Oct 27, 2009
    Messages:
    3,015
    Likes Received:
    2,013
    Location:
    BDU, BJC
    HBA search function!! google bingelis!!
     
  9. Aug 30, 2015 #9

    foolonthehill

    foolonthehill

    foolonthehill

    Member

    Joined:
    Aug 30, 2015
    Messages:
    22
    Likes Received:
    21
    Location:
    Morgantown, KY
    I build fiberglass fuel tanks every day. no gel coat, vinyl ester resin. One ply of veil, one ply of 1.5 ounce mat, one ply of 7500 cloth. That's it. It needs to be sloshed, and several componies make the right material for use with a composite fuel tank, but do make sure you use a product that specifically says "for use with fiberglass or composite" tanks.
     
    cheapracer and tunnels like this.
  10. Aug 30, 2015 #10

    Dan Thomas

    Dan Thomas

    Dan Thomas

    Well-Known Member

    Joined:
    Sep 18, 2008
    Messages:
    4,872
    Likes Received:
    2,083
    Sloshing is a bad idea for fuel tanks. It was frequently done years ago to stop weepy tank leaks, but inevitably some of it would peel off due to poor bond or simple age or alcohol in the fuel, and it would plug the tank outlet and cause engine failure. Randolph still sells sloshing compound "For Sealing Seaplane Floats Only" or something like that. Probably got sued several times.

    I wouldn't slosh even a new fiberglass tank with anything that has a chance of coming loose. Might be fine for a boat. My fiberglass tank was tight from the day it was made. Perhaps there is some magic stuff now that is guaranteed to stay put no matter what?
     
    tunnels and TinBender like this.
  11. Aug 31, 2015 #11

    tunnels

    tunnels

    tunnels

    Banned

    Joined:
    Sep 7, 2014
    Messages:
    559
    Likes Received:
    21
    Location:
    china is my home , place of work but was born in N
    Thank you just what I needed !!
     
  12. Aug 31, 2015 #12

    tunnels

    tunnels

    tunnels

    Banned

    Joined:
    Sep 7, 2014
    Messages:
    559
    Likes Received:
    21
    Location:
    china is my home , place of work but was born in N
    I was anticipating making the tanks in 2 halves and a inspection plate on to with all the pipes fitted and bolted on Its what's done with boat tanks but never seen anything here about doing it !!Good idea or not ?? never take any pipes out of the bottom they always fitted in the top!
     
  13. Sep 2, 2015 #13

    tunnels

    tunnels

    tunnels

    Banned

    Joined:
    Sep 7, 2014
    Messages:
    559
    Likes Received:
    21
    Location:
    china is my home , place of work but was born in N
    For marine use I have always done the following !
    To save having to do secondary bonding just make each half in one go !!
    if you use the right glass it does not have to be a heavy lay up and end up a heavy tank ,
    heat curing I feel also is very important .
     
  14. Sep 12, 2015 #14

    tunnels

    tunnels

    tunnels

    Banned

    Joined:
    Sep 7, 2014
    Messages:
    559
    Likes Received:
    21
    Location:
    china is my home , place of work but was born in N
    Does any one mount all there pipes and fuel gauge senders etc into a bolt on plate on the top of there tanks ??
    The same plate if big enough could be used to undo and take off to clean and inspect the inside of the tank maybe ??
     
  15. Sep 26, 2015 #15

    tunnels

    tunnels

    tunnels

    Banned

    Joined:
    Sep 7, 2014
    Messages:
    559
    Likes Received:
    21
    Location:
    china is my home , place of work but was born in N
    Sloshing AS YOU CALL IT should never have to be done if the tank is made properly and with some care and attention !! also layers of resin backed with VAIL is always a good safety measure ! There are special pigmented coatings resins that can also be used ! Personally seeing the fuel moving around in a tank is not and issue and is beneficial because im able to see how much fuel is still there ! As I have already asked about all services being in the top of the tank all fixed and welded into a plate on the top that is gasketed and bolted down !in the event of condensation or any sort of contaminate from dirty or stale fuel the plate can be removed for cleaning and inspection !! Spiral winding of continuous glass roving's makes a light and very strong tank ,also no sharp corners but every corner has a big radius !!
     
  16. Sep 26, 2015 #16

    Lendo

    Lendo

    Lendo

    Well-Known Member

    Joined:
    Feb 7, 2013
    Messages:
    358
    Likes Received:
    56
    Location:
    Brisbane
    Bill,
    I remember that thread, how did the paint go over that Silicone seepage?
    I've been trying to think of a way of eliminating that problem without any extra weight!
    George
     

Share This Page



arrow_white