get amazon web service unsigned URLs in c#

I m using amazon sdk for .net i have uploaded a file in folder of my bucket , now i want to get the url of that file using this code

 GetPreSignedUrlRequest request = new GetPreSignedUrlRequest();
        request.BucketName = "my-new-bucket2";
        request.Key = "Images/Tulips.jpg";
        request.Expires = DateTime.Now.AddHours(1);
        request.Protocol = Protocol.HTTP;
        string url = s3.GetPreSignedURL(request);

but this is returning url with key , exipration date and signature but infact i want to get the url without them , there is no other method to get the url

**Things i tried **

i search and found that i have to change permission of my file

i have change the permission of file while uploading

request.CannedACL = S3CannedACL.PublicRead;

but still its returning the same url http://ift.tt/1EwOXyK

it work when i remove keyid ,expire and signature but how can i get url with out it , or do i have to do it manually