title: Radio-button checked overriden by ngModel
body: <p>When declaring a ngModel to a radio group it appears to override the default radio button selection assigned by [checked]=&quot;true&quot;</p>
  <pre><code>     &lt;!--Radio buttons for units--&gt;
        &lt;ion-list-header style=&quot;color: white&quot;&gt;
          Units
        &lt;/ion-list-header&gt;
     &lt;ion-list radio-group [(ngModel)]=&quot;units&quot;&gt;
     
      &lt;ion-item&gt;
        &lt;ion-label&gt;Metric&lt;/ion-label&gt;
        &lt;ion-radio [checked]=&quot;true&quot;  value= &quot;metric&quot;&gt;&lt;/ion-radio&gt;
      &lt;/ion-item&gt;
      &lt;ion-item&gt;
        &lt;ion-label&gt;Imperial&lt;/ion-label&gt;
        &lt;ion-radio value=&quot;imperial&quot;&gt;&lt;/ion-radio&gt;
      &lt;/ion-item&gt;
    &lt;/ion-list&gt;
  </code></pre>
  <p>Therefore there is no checked button by default when the button group is in view.</p>
  <p>I have tried placing the ngModel within the radio button tag, the ion-item tag, both methods throw an exception:</p>
  <blockquote>
  <p>Uncaught Error: Uncaught (in promise): Error: No value accessor for
  form control with unspecified name attribute
  _throwError@http://localhost:8100/build/vendor.js:27548:20</p>
  </blockquote>
  <p>Any inout appreciated.</p>