Posted Wednesday, July 6, 2011 @ 04:46 AM
Collin,
that's a very good idea. Thermalling the 5b is great performance-wise, but handling-wise there are probably room for improvements. As you proved with your removable weight the underlying problem is that the RF 5b tend to get nose-heavy(=the elevator needs to provide a lot of down-force) when flown solo. VGs might help, but sealing the elevator gap is probably a first step.
When I sealed the gaps on "SE-UDI" I ran out of tape after sealing the ailerons(upper side only) and rudder(both sides) so I never sealed the elevator gaps. I still found a noticeable improvement on low speed performance (thinking mostly of roll-rate) where as you know you often need full aileron + rudder.
I thought the 5b already had a great handling in pitch, so I didn't think it would make much difference to seal the gaps there. Following your reasoning I see there is maybe even more reason to seal the elevator. That can be done on both sides, I would suggest to start with that if you haven't already done it. I would have loved to try it out myself, but that will have to wait for a while yet. Very interesting quest, to improve thermalling performance of the RF 5b. Which is already in my opinion among the absolutely best a motorglider can provide.
I can't help but wonder how much René was involved in the design of it, or was it more or less a Sportavia endeavour?
May the 4's be with you/ Jörgen
P.S. I had to cut slots in the seals around the hinges, where the fabric is not smooth to avoid possible jamming. I suggest if you try VGs to be conservative in the placement and keep them well spaced from the seals. D.S.
[Edit by Jorgen on Wednesday, July 6, 2011 @ 04:51 AM]