At last I fitted the feathers to my Jodel D11, I wish I had done it earlier. I have always had trouble landing the Jodel nicely, It tended to drop onto the runway at indicated 40+ knots. It did not want to "float" at all, the speed would bleed off and, at 40 something it would just stop flying even with the stick back as far as I could get it. As a result I always "wheeled" it on at 50+ (knts) And I must say I was quite good at it.
After fitting the VGs the first take off I climbed out at normal 650 ft p min. BUT I had 70+ knots on the clock!!!...At an indicated 60 (normal climb speed) I had 800 + ft p min. I had performed stall checks as you suggested. The Jodel does not stall in the traditional sense.. As the nose comes up it would just start to shake a little from side to side, wag its head sort of...and just lose height at that angle of attack, the steeper the angle the faster you lose height. There is no nose drop. Now it's different................ I tried low power stalls 1000rpm. (as before) the aeroplane reached a ridiculous angle of attack . Felt like 30 degrees plus..a quick glance at the ASI showed 22! knts or so losing around 3-400 ft p min. Appeared to be hanging on the prop. Absolutely steady as a rock... Still no proper stall.
The landing was interesting, I came over the fence at a similar speed as usual, maybe a little slower.. I held off and off and off. just getting slower and slower, I used up almost 1000meters of runway, I was making plans to go around when touchdown! on the mains still. but at 30 or so, I have to do more testing and see what has happened to speeds and consumption. I'll let you how that goes... Brilliant result so far...............
Later - Now I'm doing really slow and gentle three-pointers, and really enjoying it!
ps - I did try VGs under the horizontal stab but found that they changed the trim and caused some drag. No need for them there anyhow, as the large elevator has enough authority already.
.Thanks again, Geoffrey