Some number crunching..

I took the log of my Flytec vario / gps / recorder and loaded it into an OpenOffice spreadsheet, where I parsed the data to get some neat numbers for the latest flight of the Pelican.


First, the original video of the flight :

Here is the climb altitude in meters, plotted vs time in seconds:

It shows a steep climb to 80 meters, and then a bit slower descent .. the reason it goes below zero, is not because we crashed and went underground, but because our runway has quite a bit of slope. it is about 20 meters lower at the end.





This one, is the climb/descent rate on m/s Vs time in seconds:


It seems to agree with a steep climb at about 4.6m/s, then a dip (need to look for that on the video) and then a slow descent at about 2m/s .

I think that the bottom dip at second 49, is because a bad GPS distance computation during the turn.. (Someone knows how to take care of that?)




This is aircraft speed, (computed from the GPS log, so it skews way off during the sharp parts of the turn)

The speed is calculated from the GPS lat/long deltas plus vertical speed component, so I am sure there is quite a bit of error there. Still, the graph shows most of the flight between 35 and 70 kph..  about what the nominal stall to VNE is listed for a goat.


And finally, the GPS Lat/Long data plotted as points on an x/y axis.






I am guessing it is a pretty ugly graph, (Looks flattened to me) because I have not yet compensated on my formulas for the fact that lat and lon degrees don't map 1:1 on an x/y graph.. ( It is more like  10:8 depending on the latitude. )

Anyway, it still illustrates the plane taking off from left to right, making a turn and back to the runway for landing.

You can clearly see the data points (1 per second) spreading out as the glider speeds up and then closing together after the landing on the top right.


Hope someone finds this useful.

Alx.

Little things, make big things happen.

Gap seals! What a difference something so simple can make. 

After a brief email conversation with Mike Sandling (Designer of the goat) where he commented he was surprised to see the ineffectiveness of  our alierons, (something that we also noticed but thought was part of the design..)  we decide to figure out what was happening. 

Mike suggested it may be the control lines.. So, we checked the tension of the control cables, and those where fine. 

* BTW our GOAT is a slightly modified version of Mike's original, it was built for us as a kit by Mike Balogh  of  New York (Excellent workmanship, and really nice guy to work with) 

The Super goat uses all steel cable controls and a more "ultralight" type of build on several other items. Mike Balogh calls it a "Super Goat". 

On the super goat, the aileron control works using a two foot axle which has on one end the control stick and on the other a small arm where the control cables connect. 

[picture of the arm goes here] 

Then, we checked the travel of the aileron and the control stick.. and that was OK, but we noticed that the to get full travel on the aileron, you had to move the control stick full travel too.. something that is quite difficult because 3/4 travel, the stick is already hitting my legs!

I still have to check for my options here.. one would be to extend the control arm at the other end of the axle that the stick is attached to.  We are still debating on that one. 

The third idea was an actual mistake on our part.. On the rush to fly the little plane, we delayed the  install of gap seals on the control surfaces..  Oh, what a difference that made!

Car tow at 50kmh, 600m runway, 200m rope, Max Altitude 120m

This video is *after* we installed the seals, and although I still have the problem with the control stick hitting my legs, it is clear that I  am not using nearly as much rudder as I did in my previous flight.

On this flight, I am able to make a much better turns, losing less altitude and feeling in better control of the plane. I am pretty sure that if we resolve the control arm issue, the plane will be even sweeter to fly.

Last think I want to mention is, how easy it is to fly !  I mean, if there is a plane to teach someone how to fly (Very inexpensively by the way).. This is it!

Along with my flight, we got several other ultralight pilots to go for a ride (Just short take off and landings) and  the consensus was clear;  this is a very gentle plane. It flies almost in "slow motion" making it ideal to teach newbies how to fly.

My idea is to get a zero time pilot to do a few lessons on our slowest tandem ultralight and then switch them to the goat to further their learning.

I'll keep you posted.