In the past, I have drawn attention to my observation that for some aircraft, "best" glide speed may not be best for everything. Nearly all Flight Manuals present a best glide speed. This speed is presented to meet the certification requirement:
Sec. 23.71
[Glide: single-engine airplanes.]
[The maximum horizontal distance traveled in still air, in nautical miles, per 1,000 feet of altitude lost in a glide, and the speed necessary to achieve this must be determined with the engine inoperative, its propeller in the minimum drag position, and landing gear and wing flaps in the most favorable available position.]
I have opined that arriving to short final/top of the flare at best glide speed as above, may result in disappointment, when one pulls to flare. If you have not stored speed (energy) with which to flare, your more steep than normal approach path might be impossible to fully arrest, and thump.
While bimbling around in the Super Cub this evening, I did some experimenting. (knowing that this Super Cub is an amateur built version, with no Flight Manual). While referring to the VSI and ASI, I glided. I glided at speeds from 50 MIAS to 75 MIAS. I was seeing rates of descent from 400 to 900 FPM. The experiment was to successfully "flare" at altitude, power off. Could I use the stored speed I had, to arrest the rate of descent? Knowing that VSI's lag, I figured that seeing a positive rate without adding power could be taken to mean that I had arrested the descent to zero, with a little extra time to judge a landing.
While gliding at 50 MPH, and 400 FPM, raising the nose to flare resulted in a VS reduction from -400 FPM to -300 FPM, not really enough to flare effectively, then the plane stalled. Gliding at 70 MPH and 800 FPM, I was able to arrest to zero FPM, and hold it a couple of seconds. 75 MPH and 900 FPM allowed a pull to achieve 150 FPM up for a second or so, so more than needed to flare.
I am therefore satisfied that gliding this plane at 50 MPH (not that there is a Flight Manual speed presented anyway) would result in a very heavy landing - so I did not try to the ground. My subsequent 8 power off touch and goes were generally flown 70 MPH short final to 60 MPH over the fence, and each resulted in a nice wheel landing.
If I had to make it to shore, I might glide at 55 to 60 MPH, but I would try to speed up to 70 MPH on final, and then hope to peep it on. I'll experiment with a couple of other types as I have to opportunity.