Ben-Erik Ness Posted October 29, 2018 Share Posted October 29, 2018 I'm in the initial phase of building a PSS Dash-7. I flew with this iconic STOL plane in the late 80's and would like to give this "old lady" a new life on the slope. I'm at a wingspan of approx 97 inches. Construction method is white foam, that I 'm going to cover with abachi or balsa. I'm wondering about choice of airfoil. I'm not building a speed ship, this is going to be a sloper that can handle lesser lift than the combat and speed models. I'm considering Eppler 205 with 10% increased thickness, and know that the good old Clarck Y will also do the job. So what say you all??? Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted October 30, 2018 Share Posted October 30, 2018 Hi Ben-Erik, I recall John Hill making a similar scale Dash 8 for PSS back in the late 80's, that too was veneered white foam construction and flew very well indeed with an AUW of approx. 12lb. You can't go wrong with either of the two sections you mention - The Clark Y and Eppler 205 flat bottomed sections have proved most popular with PSS model designers over the years - they perform well, enable a good speed range and are not too slippy - ideal for scale models. If the full sized aircraft has a relatively thick wing section we've proven it quite acceptable to increase the thickness of the model section by up to 25% to produce a wing of similar appearance and still achieve a good flying performance. So your suggested +10% will be just fine IMO. Are you going to treat us to a Dash 7 build blog?? Quote Link to comment Share on other sites More sharing options...
Ben-Erik Ness Posted October 30, 2018 Author Share Posted October 30, 2018 Phil! Thanks for your reply! John Hill's Dash-8 is an inspiration for sure! I'm in the foam cutting stages, and dont have much to show right now. I also have to figure out how to upload some pictures to this site... Ben-Erik Quote Link to comment Share on other sites More sharing options...
Callsign Tarnish Posted October 30, 2018 Share Posted October 30, 2018 I'd hate to disagree with Phil but both the Clark Y and E205 are old sections which have been surpassed, especially the archaic Clark Y! I would recommend either the S3021 (a modernised and slightly thinner E205) which will have a slower speed range and be a bit 'stoogy' or the E374 which is a great all round slope section and will allow you to carry momentum far better, recently used on the mass build Hurricane with success. Quote Link to comment Share on other sites More sharing options...
Andy Meade Posted October 31, 2018 Share Posted October 31, 2018 Sounds like a nice model Ben, please post a build blog if you get the time Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted October 31, 2018 Share Posted October 31, 2018 Posted by Ben-Erik Ness on 30/10/2018 21:43:33: Phil! Thanks for your reply! John Hill's Dash-8 is an inspiration for sure! I'm in the foam cutting stages, and dont have much to show right now. I also have to figure out how to upload some pictures to this site... Ben-Erik As to uploading pictures Ben you first of all create an album and upload the pictures from your PC or phone (I use my phone which is much easier), then insert the pictures using the camera icon above, first of all putting your cursor in the right position on the post. Alternatively you can insert pictures which appear elsewhere on the web by right clicking the picture, copying the URL and inserting it using the other image icon above which looks like a picture landscape. Quote Link to comment Share on other sites More sharing options...
Ben-Erik Ness Posted October 31, 2018 Author Share Posted October 31, 2018 I think I figured it out... This is still early stages, so when I have more to show, I'll start a more detailed build thread Quote Link to comment Share on other sites More sharing options...
Ben-Erik Ness Posted October 31, 2018 Author Share Posted October 31, 2018 Posted by Callsign Tarnish on 30/10/2018 22:41:09: I'd hate to disagree with Phil but both the Clark Y and E205 are old sections which have been surpassed, especially the archaic Clark Y! I would recommend either the S3021 (a modernised and slightly thinner E205) which will have a slower speed range and be a bit 'stoogy' or the E374 which is a great all round slope section and will allow you to carry momentum far better, recently used on the mass build Hurricane with success. I'll check them out. Clark Y and E205 are a "old as the hills" but they do work don't they? I'm in search of a slow flying high lift capacity airfoil… This won’t be a plane with fighter-like capabilities, as the Hurricane… Ben-Erik Quote Link to comment Share on other sites More sharing options...
Ben-Erik Ness Posted November 4, 2018 Author Share Posted November 4, 2018 I will have to take some overall scale liberties, but the actual plane had rather thick wing profile, and I need to replicate that, t least in the wing close to the fuselage. Both in order to acvheive some close to scale appearance, but also being able to build in hollow aluminium pipe as a wing-joiner! Form bout 25% of the inner wing and outwards, I'll merge the airfoil into for instance E 205. I'm also planning to build in about 1,5 positive incidence. Quote Link to comment Share on other sites More sharing options...
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