entry speeds / how to do.... basic aerobatics Waiex?

[mike.smith]

Legacy Sonex, AeroVee 2.1. Fuel tank w/ finger strainer --> Braided fuel line --> Firewall --> In-line fuel filter --> Braided fuel line to AeroInjector (technically it's not called a "carb"). I think I have a #2.5 needle. No gascolator. No outside air to the air filter; all air from under the cowl per Sonex plans.

All fuel lines from the firewall on, are insulated with fire sleeve, hot water pipe insulation, and reflective heat tape. Fuel lines are mostly straight shots, except for the 90 deg turn from the tank to the firewall, and the 90 deg turn into the AeroInjector inlet.

Vent goes vertical from the tank, above the cowl, then 180 deg back down to vent at the bottom of the cowl. The aluminum tubing at the bottom of the cowl is bent slightly to face into to the wind (to prevent negative pressure from air across the tub).

Have never had any issues whatsoever with the AeroInjector, and have never even had the engine hiccup during aerobatics. At high Gs the engine runs perfectly normally. Approaching negative G's the RPMs will begin to slow down a bit, but not a whole lot. The only throttle adjustments are to control airspeed and RPMs. I've never needed to work the throttle to keep the engine running.

Maneuvers: rolls, 4 point rolls, loops, 7-turn spins, hammerheads, Cuban 8's, etc.

[Bryan Cotton]

Hey all,
Your input and videos on entry speeds were really helpful. Question for the Aerovee acro pilots: What do you use as RPM limits? I noticed in my spin/roll video that I got a little over 3600 during the dive to 120. Redline in the manual is 4000 RPM. Are you working hard to keep it under 3400 RPM, or just under 4000?

Thanks!

[GraemeSmith]

I set redline at 3,400 and try and stay under 3,200 when going downhill on a loop. It's too easy to overspeed. I work the throttle - like I do in other acro planes.

My fuel is a straight "uniform grade" (for want of a better description) downhill run from the bottom of the tank to the AeroInjector. There is a large gascolator on the firewall on the way. All covered with glass/silicone firesleeve - or taped over with layers of glass/aluminum reflective tape. Even the Gascolator bowl.

Exhaust pipes are wrapped with glass tape - full length.

--

ENSURE AIRCRAFT IS <950lb GROSS
CG in Aerobatic Range

MONITOR G Meter on EFIS All speeds KIAS

Aileron Rolls 3G 80-130
Barrel Rolls 3G 120-130
Chandelles 69-95

Hammerhead 100-110
(AVOID TAIL SLIDE)
Loops / Cloverleaf 3G 125-140
Lazy Eights 69-109
Horizontal Eights 125-140
Snap Roll NOT RECOMMENDED

Spins 35-40
Split S 60-70

Stalls <40
Whip Stalls PROHIBITED
Wing Over 78-95

[mike.smith]

Graeme's numbers are pretty close to mine (for aileron rolls I prefer not being slow, so 120 kts for me is the usual pull up speed). You do have to watch the revs and work the throttle on the downhillls.

[Bryan Cotton]

I posted this video in my photo thread:
https://youtu.be/ZjJ2CCP6KVk?si=AJUgcO0tI_TEAcYx

The loop around 2:20 in the video - totally forgot to push the throttle in on the way up. I have to pull out a lot of power to keep the RPMs below 3400 in the dive to 140. Tells me two things:
1) 140kts entry is probably enough to make it around the loop without power
2) The contribution of the 80hp engine is minimal

[Bryan Cotton]

Hey all,
I tried my first hammerheads in the Waiex today. They were pretty ugly! Kept ending up inverted rather than straight down. It has been a long time since I've done hammerheads, but have done them in an F28A and a Pitts S2A. I figured that maybe I was pulling back on the stick by accident or something, and then tried to make sure I didn't do that. Do you guys go forward stick on the kick over? I sort of remember doing that with the Pitts but I thought it was a subtle thing and used for style points, i.e. keeping it perfectly vertical through the pivot to the downline. If anybody had experience in the Waiex or Sonex they want to share I'd like to hear it. I am not sure if the conventional tail feels the same as the Y tail in this maneuver.

I did my pullup at 140kts, same as my loop entry speed. I know in this thread that some do them at lower speed but I figured that would give me more time in the vertical to figure out when it was time.

It was still fun, and the champions of our airshows and aerobatic competitions are safe from me for a little longer.

[Bryan Cotton]

I am wondering if maybe I was subconsciously putting in some right aileron when I kicked in right rudder. Would make sense for what was happening.

[Bryan Cotton]

https://youtu.be/gPbcODcmFfc?si=nKzv5fwgU5l3XR-w

[Tnhelm]

It appears to me that when you start the turn/pivot on top with the rudder, the airspeed is still high enough to cause more lift from the outer wing than the inner, resulting in the roll to inverted. When I taught basic aerobatics in the Citabria, it was frequently necessary to apply near full opposite aileron the keep the pivot on the top vertical, as indicated by the inside wing visually slicing backwards in reference to the ground. In fact that was my reference when making the reversal, watching the inner wing slice backwards and controlling the roll tendency with opposite aileron.
I have done the hammer head turns in my OneX which turned out well, although one got a little slower than desired on top and the airplane just barely pivoted around to downward. That was too close for me in avoiding a vertical tumble or tail slide. It probably looked good from the outside.
Tnhelm
Onex 0137

[Bryan Cotton]

Thanks Tnhelm, good description. Makes sense.

In the Pitts I was taught to wiggle the ailerons a little on the up line, and when they went unresponsive that was a sign the airspeed was low enough to kick over. I'm wondering if this technique would also work in the Waiex. You need that goldilocks airspeed on top - not too fast, not too slow. I probably erred on the too fast side.