Hi Kevin,
We went out this morning and performed some sink rate tests with the
engine off and the prop feathered. We got 270 fpm at 52 KIAS (59 kts
TAS) at 7000 ft altitude, and 357 fpm at 60 KIAS (68 kts TAS). These
are still somewhat preliminary numbers due to weather conditions this
morning. The glide ratios are about 22:1 at 52 KIAS and 19:1 at 60
KIAS. This seems a little odd, as I would have expected 60 kts to be
better than 52 kts, but as I said, this is rather preliminary.
We have used glider tape to gap seal the wing roots, ailerons, and air
brakes. We do not yet have fairings for the outrigger legs and do not
have cowl flaps yet. We expect both of those things to improve sink
rate / glide ratio, especially at the higher speeds.
Our CG with the short wings is 58.9" (900 pounds), and with the long
wings is 60.4" (1003 pounds). The long wings moved our CG to the rear
almost an inch, to just aft of nominal center of range.
regards,
Terry Seaver
A135 / N135TD (motor glider at the moment)
Pleasanton, CA
-----Original Message-----
From: owner-europa-list-server@matronics.com on behalf of Kevin
Klinefelter
Sent: Fri 2/29/2008 4:52 PM
Subject: Re: Europa-List: Motor glider first flight
Terry & Dave,
Congratulations!
I imagine that your sink rate tests were with the engine off and the
prop feathered?
Did the CG change with the long wings installed? Best LD will be found
near the aft limit.
Have you sealed the gaps in the wing root?
Glad to hear you guys are gliding... Kevin
Terry Seaver (terrys) wrote:
<terrys@cisco.com>
>
>
> Dave DeFord and I have been flying our short winged mono-wheel Europa
> for over 6 years now, and have been working on interchangeable long
> wings for the past four years or so. We finally finished them and had
> our first flight yesterday morning.
> There was no drama, everything went well. We got in a total of four
> flights, two each. A few comments are as follows;
>
> 1) There is a slight tendency to roll right, most noticeable a 100+
kts.
> We are not sure yet what is causing this.
>
> 2) Very preliminary tests of the minimum sink rate were 400 fpm (at 50
> kts indicated), later test indicated 350 fpm (at 52 kts indicated)
after
> taping up the aileron and airbrake gaps. We had hoped for 250-280
fpm,
> so we need to look for ways to improve this. Fairings for the
> fixed-down outriggers are probably a good place to start.
>
> 3) The airbrakes are not as effective as the spoilers on the Katana
> Extreme we got our glider ratings in last September. The air brakes
> also cause a pitch/speed change, which causes some porpoising on
landing
> if the brakes are used to modulate your approach/flare. The plane
also
> tends to float a while in ground effect, even with full airbrakes on.
>
> 4) The mono-wheel twitchiness on the ground is greatly reduced by the
> bigger, heavier wings.
>
> 5) The long wings add 103 pounds to empty weight, compared to the
short
> wings.
>
> 6) Stall speed is about 45 kts indicated, with and without airbrakes
> applied. As stall speed approaches, the plane just gets loose and the
> nose bobs up and down. No tendency to break, it just bobs up and
down,
> complaining about it. We haven't tried accelerated stalls yet.
>
> Please note that these test are very preliminary.
>
> Regards,
> Terry Seaver
> A135 / N135TD
> Pleasanton, CA
>
|