SonexBuilders.net

I'm not a Waiex builder but I am going to be a Waiex pilot soon. For at least a few hours anyway. A good friend built a tailwheel Waiex and has asked me to do the test flight. I built a Van's RV-4 and a Rans S-6ES Coyote II. I have about 1500 hours total time, 1200 of which is tailwheel time. I did the first flights on both my airplanes.

The plane I will be flying is the tailwheel version, with the AeroVee 80 HP engine. I should say flying if I can work out how to grab the brake handle. Yes, I know I shouldn't need it but still. :)

So I have a couple of questions I hope someone can answer for me.

1) How do you do the run up? The brake handle and the throttle are both operated by your left hand. How do you guys deal with that?
2) Can someone give me some target V speeds? I know each plane is going to be subtlety different on it's speeds depending on build and equipment and pilot weight. :) But I could sure use at least some targets to aim for. Vy? Approach speed?
3) Any other tips for a first flight on a Waiex? I've never flown any kind of Sonex aircraft but I figure it's just another airplane. No offense intended! :)

Hello and welcome to the group! I'm glad to hear that you're preparing another Waiex for its maiden test flight. Where are you (and the airplane) located?

Overall, I think you'll find the Waiex similar in a lot of ways to your RV-4 in feel. The ailerons should feel very familiar to you and I think you'll find the elevator feel (pitch) probably a little lighter than the RV but still comparible. Be ready for light control forces!

As for your questions, a lot of people will rig the brake handle so you can "lock" the brake in a flap detent, thus making a parking brake for yourself. Did the builder do this? If not, you will probably need to hold the brake with your left hand while manipulating throttle and ignition switches with your right. Not a terrible chore but one made much easier with a properly rigged brake handle that uses the flap detents.

I recommend an initial climb speed of 80 miles per hour but be prepared to increase that to 90-100 if the rear cylinders start to get hot. The AeroVee manual tells you what CHT readings are acceptable, but previous experience indicates that, if you're climbing out and see EGT's over 1300-1350 degrees, the rear cylinders will quickly go over 400 degrees. On my AeroVee, I look for an initial full throttle rpm of at least 2950-3000 early in the takeoff roll or else I abort and troubleshoot. Pattern speeds that work well are: downwind leg-100 miles per hour, slowing to 90 abeam the numbers for the first notch of flaps; base leg at 85-90 miles per hour; final approach around 75-80 miles per hour. These numbers will give you plenty of energy for maneuvering and setting up the flare. If you're operating out of a really short runway, you may want to aim closer to 65-70 miles per hour on final. I also recommend not using the full 30 degrees of flaps intially; they have a lot of drag and if you have an issue with the engine, you may run into problems. Stick with 10 or 20 degrees at first. Also, as a Waiex owner myself, I also recommend you make the first few flights with crosswinds of 5 knots or less. It can handle more but the Y tail isn't the same as the "normal tailed" Sonex in strong crosswinds. Everyone has different crosswind limits, but for per personally, I generally won't go up with crosswind components of more than 8-10 knots.

I recommend you look over at http://www.sonexfoundation.com for a lot more useful information on the airplane, including some expert tips from Sonex factory employee Joe Norris who runs the factory transition training program. The big pointers he offers (among others) is that the Sonex is a fingertip airplane and it's normal for new pilots to get into a pilot induced oscillation (PIO) until they get used to the light control feel. You also sit very low to the ground, so it's normal for people to flare way too high. These airplanes are lighter than your RV and will slow down in a hurry once you close the throttle and set up in the flare, so be careful.

Finally, make sure the engine is running well before flying the airplane. These airplanes are very overbuilt so no worries there; most people who have first flight issues have some sort of engine trouble.

If you have any more questions that I can help with, give me a call!

Mike
614-595-3521 (cell)

svanarts wrote:I've never flown any kind of Sonex aircraft but I figure it's just another airplane. No offense intended! :)

You come on here with that attitude and expect help? "Just another airplane?" Come on man!

Just kidding of course! With your skill level you should do fine but I'd still recommend you get a ride in a Sonex if at all possible just so you can feel the controls and get the sight picture for landing. As far a numbers go ... first flight numbers may be a bit different as you are also breaking in a new Aerovee and sometimes they get quite warm until the rings seat. Here is a good thread to read regarding first flights with an Aerovee powered Sonex.

viewtopic.php?f=21&t=1135&hilit=first+flight

Keep us posted and get plenty of video!

Dale
N319WF

When I do my runup I hold the brake locked with my left leg. Pull the brake on, push out with your leg, and the brake should stay locked long enough for the runup.

In a Sonex type airplane, you are more worried about being too low on final than being too high. You can always use the flaps and a slip to loose altitude fast if you need to.

Lots of good advice here. One more thing to remember is that it is a light aircraft so ease the throttle out on short final as opposed to 'chopping' it. The speed will bleed quickly with those flaps.

Jim Hicke
Waiex 0162 3300 TD

Hey guys thanks for all the advice and the links. The builder is pretty anxious for me to fly it but I really want to get comfortable with it on the ground first.

The plane was built by Ken Scott and is based in Oakdale, CA (O27) He's done a great job on the build. I don't doubt the airframe at all. He built the engine too and while I don't doubt his mechanical abilities, I doubt all new engines. :)

O27 is a 3000 foot strip which should be plenty. The plane I fly now is pretty light so I'm used to high sink rates when power is chopped.

Mike, you said the Waiex handles crosswinds a little differently than the Sonex. Can you explain? I've never flow a V (Y) tailed aircraft so not sure what to expect there. Luckily Autumn is when we traditionally have very light winds here in central California.

You won't have any surprises. The Waiex has no bad habits and plenty of rudder authority. I certainly wouldn't do a first flight with much of a crosswind component though. Mine flew literally hands off on my first flight. I didn't even start messing with trim until several flights later. The controls are just that light.
My advice would be rotate around 55mph, climb at 80, cruise around 120 in the pattern to cool the heads, approach no less than 65. You can adjust those numbers as you get more comfortable with the plane.

You may want to put a small stripe of white tape on the glare shield pointing forward. The bends in the glareshield are angled toward the center of the aircraft and can deceive you into thinking that the bend in the glareshield is pointing straight forward. This was one of the first things Joe Norris mentioned to me in the Sonex Transition training. If I were you, I would insist the builder pay for both you and he to attend the transition training. It is a small investment in your well being and well worth it. I too have 1500 hours plus and experience in RV8's, PiperSports, T-34's, and other sporty aircraft as you have and for me it was the best $850 I have ever spent.

Also, don't be afraid to do a little ground running and make sure the mixture adjustment on the AeroInjector is correct. Follow the AeroInjector manual to verify the mixture setting is correct. Too lean and you will overheat the heads and the exhaust gas. Too rich and the engine will miss and bog down. But, please follow the manual and make sure everything is working properly. Safety comes first.

svanarts wrote:Mike, you said the Waiex handles crosswinds a little differently than the Sonex. Can you explain? I've never flow a V (Y) tailed aircraft so not sure what to expect there. Luckily Autumn is when we traditionally have very light winds here in central California.

Nothing to worry about. You'll find the Waiex has TONS of rudder authority in cruise. Like the factory says, unless you have a mirror, you'll never know you're flying a Y tailed airplane. It handles just like a "regular" tailed airplane!

Even slowing down through 100 miles per hour, you'll still have a lot of rudder authority from the tail. What I find ON MY AIRPLANE and with MY PILOTING TECHNIQUES (which is probably the problem!), once I get down into the 50-60 mph airspeed range (down in the flare), I can run out of rudder authority on days with decent crosswinds. Everyone has different limits and there are people on this board who are happy flying their Waiexes with strong crosswinds. My only advice is to approach is to start out by flying on days when the winds are light and build up from there. Of course, that's not just advice for a Waiex; I normally tell everyone the same thing!

You're getting tons of great info; I sure hope it helps. Any other questions we can help answer?

Remember, in the world of homebuilt airplanes, every airplane is different (even when built from kits). And as Mike mentioned, every pilot is different as well. So, one particular pilot in one particular airplane may find that they have different limits than another pilot in another airplane of the same type. I've landed the factory Waiex prototype in a 25 mph direct 90 degree crosswind and did not run out of rudder. It was work, but the airplane handled it fine. Certainly I'd recommend finding a runway into the wind when possible, but the airplane is pretty capable.