Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Sealant Groove For Fuel Boundary

Sealant Groove For Fuel Boundary

Sealant Groove For Fuel Boundary

Hello everyone,

I would ask you what is the advantage of groove applying to upper and lower flanges of spar/rib structures that form fuel boundary of wings. As far as I see, Eurofighter, F-16 and F-35 fighter jets have this groove to inject sealant without removing upper/lower skin. Is there any more requirement for it, such as preventing fuel leakage, blocking seperation of sealant? Or could it be designed the wing without groove channel?

RE: Sealant Groove For Fuel Boundary


I am familiar with injectable sealant grooves for wing integral tank sealing on F-15s... but I'm pretty sure that F-16s have adhesive-bonded/fastened joints for wings and fuselages sealing. Hmmm I'll have to check out F-16 sealing methods in latest pubs... to be certain [grooves may be back-up in the wings].

I have NO idea as to what 'system' the F-22 and F-35 use for integral tank sealing.

Just about every aspect of integral tank design with sealant grooves is explained/illustrated in the following documents...


SAE-AIR4069 Sealing of Integral Fuel Tanks [DoD accepted]

AGARD R-771 Fuel Tank Technology

NOTE. F-15s had grooves running-down fastener-lines... with widened [spot-faced] areas at each fastener location to allow sealant to flow-around the fastener shank. Special fasteners were installed along the grooves... widely spaced... that had hollow-shanks with cross-drilled holes which aligned with the centers of the grooves when tightened down... and had a removable plug in the center of the flush head [injection port]. A special non-curing silicone sealant was injected into these fasteners VERY carefully and slowly, under low pressure to attain a seal thru the length of the joint... or to re-seal a 'leaker'. Over-pressuring with sealant could cause a joint to open-up under pressure and be a real problem... squirting uncured-sealant in the tank. Some jets were very leaky and high maintenance... others hardly ever leaked and stayed-off maintenance radar... I knew the 'leaker' tail-numbers by heart.

NOTE. The hollow injection-fasteners were prone to in-service failure [heads or shanks breaking]... which was another maintenance headache.

Typical groove injection/non-curing current-generation sealants are as follows...

AMS3283 Sealing Compound, Polysulfide Non-Curing, Groove Injection Temperature and Fuel Resistant

AMS3376 Sealing Compound, Non-Curing, Fluorosilicone Groove Injection Temperature and Fuel Resistant

NOTE. I'm pretty sure that the use of leak detection colored dyes [typical MIL-PRF-81298] are prohibited in these style tanks.

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

RE: Sealant Groove For Fuel Boundary

Thank you for your detalied reply, Mr Taylor.

At F-16 wing, the groove channel has been used between two rows of fasteners for fuel tank sealing and sealant is injectable by holes on upper/lower skins. So, if there's a leakage at any area, they can prevent fuel leakage by injecting seal to that area without removing skins.

By the way,SAE-AIR4069 document contains so detailed information about fuel tank sealing. Thank you kindly for references.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close