Online Community of Zenith Builders and Flyers
When I built my STOL 750 about 9 years ago, the Cruzer did not exist. I had a 2100' turf strip and all my buddies had strips at least as long. So, not needing "superSTOL" capabilities, nonetheless I was impressed with the solid, all-metal construction of the STOL 750, the unparalleled visibility, and decided to build one!
I had previously flown a STOL 750 both slats-on and slats-off, so during Phase 1, I tested my 750 in both configurations. I later decided to remove the slats, add StolSpeed VG's, and did some clean-ups with fairings, 600 series tires, etc. to enhance the cruise speed - eventually ending up with a solid 82+ kts cruise. I put about 600+ hrs on the 750 in that configuration and loved every minute of it!
HOWEVER, it seems STOL is getting more popular by the minute, and I'm not flying cross-country as much as i used to, so while at the Zenith Homecoming in Mexico, MO, recently, I decided to enhance the plane's STOL performance by re-installing the slats and installing bigger tires when I got home. Roger, the demo pilot at Zenith, is a very poor salesman! ;>) Instead of convincing me I needed to build a Super Duty, etc., he said, "You don't need to build another airplane - if you re-install the slats, it'll be like a whole new airplane!"
He was right!
When I returned home from the Zenith Homecoming, I re-installed the slats, put 21" tires on the mains and the 800 series Carlisle on the nose, and got re-acquainted with my STOL 750! It was like getting back on a bicycle - it all came back to me! On my first flight, I flew up to KCSV (Crossville, TN) and proceeded to land right on the numbers. It was a fairly long taxi to the first turn-off! Some wag in the pattern broke in on the radio and said, "Next time, just land it on the ramp and save the long taxi!" LOL!
So, I'm back into re-discovering the joys of STOL!
John, interesting that your 750 experience and mine are very similar. For the first 30 hours(now have 86) I had the slats on and it would get off QUICK! I've been flying since the age of 15 - recreation then professionally and back to recreational. Like you, I operate off a private 1800 ft. grass strip with a LOT of short Super Cub strips in my area(I'm in Alaska) but as I've grown older(just turned 80 recently and in denial) operating in and out of short places is not a high priority now. I also cleaned up mine with slat removal and fairings. I also have the same tire combination as you have. With the Viking 110, I cruise at 92-93 mph so pretty close to your numbers. It's now a hybrid between the STOL and Cruzer and fun to fly.
When I put the slats back on, my cruise dropped to 79 kts - only a 3 kt penalty. I had gained 6-8 kts when I took the slats off, but apparently some of the other clean-up I did with HT fairings, HT fences and elevator tip extensions are still helping out the cruise since I didn't lose all of the 6-8 kts! I added the 21" tires after the slats and did not notice any further drop in cruise, so that's a plus!
Welcome back, your cruise speed dreams were your ticket out
Welcome back, to that short grass strip that you laughed about
Well the names have all changed since you hung around
But those STOL dreams have remained and they've turned around
Who'd have thought they'd lead ya
(Who'd have thought they'd lead ya)
To land and stop short where we need ya
(Land and stop short where we need ya)
Yeah we tease him a lot 'cause we got him touchin’ down on the spot
Welcome back, welcome back, welcome back, welcome back
Welcome back, welcome back, welcome back
Love it! :>)
took me a sec to figure it out; soon as all the welcome backs hit me I knew it.... good job!
"Awesome"... made my morning smile.
One little gremlin popped up with the slat re-installation. All of a sudden, my STOL 750, which has always flown straight and level hands-off, developed a heavy right wing after the slat installation! I had previously flown with the slats for several dozen hours many years ago, and it definitely did not have a heavy wing back then. I took a careful look at the slat installation and discovered that my gap between the TE of the slat and the wing was 20 mm on the right and only 15 mm on the left. This seemed like an obvious explanation for the heavy wing - the wing with the bigger gap would present slightly more drag since that slat would be protruding up above the wing more.
I rechecked the plans and found the spec for the gap was 19mm +/- 2mm, so the right was in-spec and the left was not. At first, I couldn't understand how this could happen since when I originally installed the slats, I set them with the template in the gap as called-out in the plans. HOWEVER, when I removed the slats years ago, I eventually "shaved" the slat brackets down to a 20mm stub height and made bridging or "intermediate brackets" to span the distance if I ever wanted to re-install the slats - looks like this:
So, obviously, somewhere in the intermediate bracket fabrication, an error in hole location crept in. Why the error was so consistent and only on one side beats the heck out of me! Ha!
I removed the top-forward intermediate bracket bolts, inserted the gap template under the TE of the slat, and re-drilled the bracket and bolted it. A subsequent test flight (with full tanks to ensure no other reason for imbalance) demonstrated that I was back to hands-off straight and level! :>)
I believe I found the same problem on 701, and one side only. Installed an intermediate
bolt in all of them
We have the slats removed from our 801, and we were just discussing whether to make it a permanent decision and cut and grind off the brackets, or not. I like your idea of leaving a shorter bracket "stub" and using an intermediate if we want to add them back. We were debating how much difference it would make in performance, or would it be just an aesthetic change. Any insight on your thinking and experience with the brackets would be appreciated!
The stub brackets have no adverse effects. Since the intermediate brackets restore the slats to their original position, no problems when slats are installed. I'm quite satisfied with either configuration!
So John, are you going to join the other Tennessee Jon and become a STOL Bandit?