# Would a fiberglass/plastic glider be invisible to radar? **URL:** \ **Category:** Factual Questions\ **Created:** [July 10, 2010, 9:46pm UTC](https://boards.straightdope.com/t/would-a-fiberglass-plastic-glider-be-invisible-to-radar/546251 "2010-07-10T21:46:37Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [July 10, 2010, 9:46pm UTC](https://boards.straightdope.com/t/would-a-fiberglass-plastic-glider-be-invisible-to-radar/546251/1 "2010-07-10T21:46:37Z")
Just curious. If a gilder was 100% plastic with a human on board could it be detected by modern radar? ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [July 10, 2010, 9:59pm UTC](https://boards.straightdope.com/t/would-a-fiberglass-plastic-glider-be-invisible-to-radar/546251/2 "2010-07-10T21:59:11Z")
radar can detect raindrops. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [July 10, 2010, 10:47pm UTC](https://boards.straightdope.com/t/would-a-fiberglass-plastic-glider-be-invisible-to-radar/546251/3 "2010-07-10T22:47:29Z")
> [@johnpost](#): > > radar can detect raindrops. As well as conventional airplanes, ships and for some ungodly reason the speed of reasonably driven automobiles in speed zones, but none of these answers the OP. ---
**Author:** ![thelurkinghorror](https://avatars.discourse-cdn.com/v4/letter/t/7c8e57/32.png) [@thelurkinghorror](https://boards.straightdope.com/u/thelurkinghorror)\ **Post date:** [July 10, 2010, 10:57pm UTC](https://boards.straightdope.com/t/would-a-fiberglass-plastic-glider-be-invisible-to-radar/546251/4 "2010-07-10T22:57:49Z")
I assume the OP means “detectable as a plane, and therefore a potential threat, hazard, etc.” ---
**Author:** ![\_Undecided\_Adrian](https://avatars.discourse-cdn.com/v4/letter/_/eada6e/32.png) [@\_Undecided\_Adrian](https://boards.straightdope.com/u/_Undecided_Adrian)\ **Post date:** [July 10, 2010, 11:00pm UTC](https://boards.straightdope.com/t/would-a-fiberglass-plastic-glider-be-invisible-to-radar/546251/5 "2010-07-10T23:00:22Z")
Well yes. Glass and especially Carbon Fiber Reinforced Plastic are not completely invisible to radar, and the long straight edges on the wings help. There’s also metal rods in the wings moving the ailerons and spoilers. Gliders are less visible than metal planes, though, and civilian radar systems normally only use secondary radar, i.e. transponder signals, which many gliders at least here in Germany don’t have. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [July 10, 2010, 11:04pm UTC](https://boards.straightdope.com/t/would-a-fiberglass-plastic-glider-be-invisible-to-radar/546251/6 "2010-07-10T23:04:32Z")
I don’t know the answer to the OP, but there are a lot of ‘plastic’ airplanes out there. For example, the [Long-EZ](http://en.wikipedia.org/wiki/Rutan_Long-EZ), the [Quickie](http://en.wikipedia.org/wiki/Quickie_Aircraft), and the [Glasair](http://en.wikipedia.org/wiki/Glasair). ISTM there should be plenty of data on RCS on them and other aircraft. ---
**Author:** ![Sage\_Rat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sage_rat/32/399_2.png) [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)\ **Post date:** [July 10, 2010, 11:07pm UTC](https://boards.straightdope.com/t/would-a-fiberglass-plastic-glider-be-invisible-to-radar/546251/7 "2010-07-10T23:07:34Z")
> **[Stealth technology](https://en.wikipedia.org/wiki/Stealth_technology#Stealth_principles)** > > Stealth technology, also termed low observable technology (LO technology), is a sub-discipline of military tactics and passive and active electronic countermeasures, which covers a range of methods used to make personnel, aircraft, ships, submarines, missiles, satellites, and ground vehicles less visible (ideally invisible) to radar, infrared, sonar and other detection methods. It corresponds to military camouflage for these parts of the electromagnetic spectrum (i.e., multi-spectral camouf Dev... > **[Radar cross section | Material](https://en.wikipedia.org/wiki/Radar_cross_section#Material)** > > Materials such as metal are strongly radar reflective and tend to produce strong signals. Wood and cloth (such as portions of airplanes and balloons used to be commonly made) or plastic and fibreglass are less reflective or indeed transparent to radar making them suitable for radomes. Even a very thin layer of metal can make an object strongly radar reflective. Chaff is often made from metallised plastic or glass (in a similar manner to metallised foils on food stuffs) with microscopically thin l... Sounds like it has a good chance of being hidden, but I imagine that it’s one of those things that would really vary based on the glider in question. One specifically made for the purpose would, obviously, be better. ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [July 11, 2010, 4:36pm UTC](https://boards.straightdope.com/t/would-a-fiberglass-plastic-glider-be-invisible-to-radar/546251/8 "2010-07-11T16:36:04Z")
> [@'\[Undecided](#): > > Adrian;12670247’]There’s also metal rods in the wings moving the ailerons and spoilers. Quite right - but there is a trend toward making these out of composite materials. It’s going to be quite a while until the last vestige of metal is gone, in things like nuts, bolts and bearings. But given a sufficient budget, it would probably be possible. The result would be an aircraft that’s hard to detect with normal radars - but given that [birds can be radar-tracked](http://www.woodcreeper.com/), not impossible.