Initial flight report...
Well, as the happy video I posted earlier showed, the "Silver BB" took to the air on 22 July 2015 at 7:15 PM for the first time. I wasn't comfortable flying this thing myself for the first flight since I had no time in anything like it. My buddy volunteered to take it up with me. He has no time in a 750 but is a 13,000 hour bush pilot and one of the best pilots I've ever seen. He owns a few Pipers and flew everything from Cessna's to Otters and Norsemen and I figured if he couldn't land this thing, nobody could!
Only condition was that I go with him. He has limited experience with glass panels and I think he figured if a wing was going to fall off, then he would be taking me out with him! LOL! We put in just over an hour on the first flight with 4 take offs and landings. Here's what we thought of the initial flight...
THE SPECS
Just to go over what I have...
-Second edition CH750 STOL with a mostly standard build.
-115 hp -O-235 Lycoming engine with Zen Exhaust
-Warp Drive 3 bladed 72" prop.
-Mix of Dynon and MGL glass panel instruments
-Dual controls
-Zen upholstery kit
-VG's on the tail
-long range tanks (15 gallons)
-14.6 lbs of ballast in tail
-Empty weight is 905 lbs (yes she's heavy)
-Registered as an "amateur" built here in Canada with a 1440 lbs gross weight
FIRST FLIGHT
I put 12 gallons of fuel in each tank, since I heard that a full tank can cause some leakage around the caps at a high AoA, plus I was heavy enough as it is! With my buddy, myself and the fuel we were close to gross weight! To make it worse, it was +38 C out. It's been unusually hot out for the last week with no end in sight. My field is in Kakabeka Falls, Ontario and is at 1000' ASL. My Dynon showed the density altitude at about 3700 feet!!! Yeah it was hot, but if anything was going to show a flaw it would be in these temps! Only snag was my KX-155 Nav/Com died for some reason. I used a handheld as a backup, but our airport doesn't require a radio and on a Thursday night, it was empty anyways. It's going to the shop tomorrow and I hope they actually find something wrong with it, because taking all my wiring apart to find an issue will suck. We were just staying in the pattern doing circuits for the first flight. Did my third walk around and triple checks and we were good to go. I was terrified, my buddy wasn't. He'd looked it over, knew I use to be an AME and knows it was inspected so he had no qualms... me I kept worrying I forgot a bolt somewhere and the wing would fall off....
Engine fired up and purred with no issues, it warmed up quickly in the 38c weather... wind was negligible, maybe 5 km/h directly from the west. The runway in Kakabeka is 09/27 so that was perfect. We taxied down and I repeated what we talked about before in our pre-flight briefing, be prepared for the nose to come up FAST, keep the front wheel off the ground and let it fly off. Got to the front of 27 and did the run up, no issues... Time to go...
Smoothly and quickly my buddy put the throttle forward, first time in motion so I wasn't sure how the tach would read. I set the prop to about 10.5 degrees that gave me a 2250 static RPM. By my guesstimates that should give me around 2600 RPM in flight. Engine can go to 2800 but I saw no need to set it that high for the flying I was doing. I planned on resetting it to 2800 when I put it on floats. Turns out I was bang on. RPM maxed out at 2610. As expected the nose came up FAST, Wheel was off the ground in maybe 20-30 feet... playing with the stick (as seen on the video) my buddy got the nose to where it should be and it accelerated fast. Nose was kept lower than it should be, just to be safe. I'm guessing the take-off run was about 350-400 feet and it didn't take off like I thought it would, seemed to "mush" a bit, but once it hit 60 mph it jumped into the air and smoothly climbed out. We both guessed the high heat and humidity was really affecting performance, but the engine was running strong and the leisurely climb was still showing 400' per minute! Put the nose down a hair and the climb out was at 70 mph... just to be safe.
A few things really impressed me when I took control. The ball was dead center on hands off! I had no heavy wing, no left or right tendencies... in the smooth air it was flying straight and true! Pitch is INSANELY sensitive. It seems I have ZERO rigging adjustments to make!!! Very smooth in the turns and the rudder is unbelievably effective. I'm guessing I was pushing maybe 1/4" max, just light foot pressure really to keep the ball centered in the turns. I had no issues with the rudder being "stiff". It felt fine. The engine blew me away. Since it's basically been sitting for 3 years during the build, we left it at max RPM for the entire flight just to burn it in and re-seat everything. Oil pressure was 62 psi, oil temp around 155F and the max cylinder head temp I got was 330F!!! This is in 38 degree weather!!! Fuel burn seemed to be about 9 gallons an hour at full power and went down to 5.5 in cruise, but I haven't fully calibrated the fuel flow sensor yet, but that should be fairly accurate.
I was worried that my baffling would keep it too hot, or I hadn't calculated the openings on the cowl properly but if anything I'll have to baffle it more in the colder weather to warm it up! The trim stayed neutral for the most part, maybe adjusted it once or twice with a light tap. We did a few medium turns and after about 15 minutes came in for the first landing. Set up on final, at 60 mph but the sink rate seemed a bit high so we came in at 70 mph, again at near gross weight and 38c was the likely cause. I had informed my buddy of what to expect, and told him the best way to land it is with the power on and just do it like a glassy water landing...riding the power curve. He followed through but he flared just a hair high, saw the sink and corrected.
The 235 engine is heavy, but the balance I have is perfect. I added 14.6 lbs of lead to the tail to compensate and the CG is perfect on all my W&B calculations for all loading configurations. In retrospect I could have put a heavy battery back there, but I have a lithium on the firewall so I added the lead. Not fun, but I saved probably $25,000 installing this engine over a Rotax. It's probably a good 80 lbs heavier than the 912, but 25K is not peanuts, plus it sounds big and mean flying overhead, can't put a price on that!
Landing turned out smooth and worked out well... his 13,000 hours came in handy! Only thing he thinks will be an issue is to make sure the rudder is neutral on touchdown, due to the steerable nose. After touchdown he looked at me and said "Holy ^&*%, you weren't kidding about the nose dropping!" LOL. We took it off the runway and parked it for a check-up. No leaks, no damage, no missing bolts and both wings were still on!!! Had a drink of water and went back up, mostly doing light air work, turns, a few steeper climbs that showed 800' per minute, not bad at near gross and so hot out! Did some other minor stuff. Max power speed seemed to be around 85 mph during light maneuvers. I didn't check it on straight and level but I doubt it got higher than 90 mph. I'm guessing it will cruise around 80-85 mph. I can live with that at about 5.5 gal/hr. Total flight time 1.3 hours. That was enough for the first flight. Three more landings were done, all but one were decent. One had a bounce. My confidence in the nose gear increased a lot after this flight... I kept thinking it was like a matchstick, just waiting to snap but it handled everything well.
More flying was suppose to happen today, but we had another super hot day and thunderstorms rolled in. We're hoping for some cooler weather to see how much effect it has on the performance, but it's suppose to be hot all week! Now that my buddy is comfortable flying it, I'll have him up with me while I get a dozen or so circuits in.
One thing I will say is that so far this is a KICK-ASS PLANE and I couldn't be more please with how it turned out!!! The fact that the rigging turned out perfect is a nice bonus. If you are building, keep at it. Trust me, it's worth it!
That's about all I can think of for now, I'll add more info as the flights continue. Hoping to get back up tomorrow. I have some more video taken of the landings. I'll work on those to post them when I get a chance.
Cheers,
Smilin' Mark
First take-off...
First flight...
