Dynamic setting input type in Angular

Please can anybody explain why this code doesnt work, i try set input types dynamically, but this is not working.

//our root app component
import {Component, NgModule, VERSION} from '@angular/core'
import {BrowserModule} from '@angular/platform-browser'
import { FormsModule }   from '@angular/forms';

@Component({
  selector: 'my-app',
  template: `
    <form #f="ngForm">

      <input [type]="rtype" value="beef" name="food" [(ngModel)]="myFood"> Beef
      <input [type]="rtype" value="lamb" name="food" [(ngModel)]="myFood"> Lamb
      <input [type]="rtype" value="fish" name="food" [(ngModel)]="myFood"> Fish
    </form>

    <p>Form value: </p>  <!-- {food: 'lamb' } -->
    <p>myFood value: </p>  <!-- 'lamb' -->
  `,
})
export class App {
  name:string;
  myFood = 'lamb';
  rtype='radio';
  constructor() {
    this.name = `Angular! v${VERSION.full}`
  }
}

@NgModule({
  imports: [ BrowserModule,FormsModule       ],
  declarations: [ App ],
  bootstrap: [ App ]
})
export class AppModule {}

also i try use type=, but this also doesnt work

I am read this http://ift.tt/2sTHNtK. But not understand why it is not working in Angular. May be angular not call http://ift.tt/2wQQdo6. Please explain.

Also when i create simple radio in html< and then try change the input type property from console it works fine for example was input.type="radio", became input.type="checkbox" in browser i see that radio changed to the normal checkbox.