Viking Engine

[fastj22]

I have 48 hours on my Waiex. I've flown at gross (1200lbs for my plane) only a few times with most of the weight in the passenger seats. I'll tell you, I don't like it. It really changes the way the plane handles. Just doesn't feel right, compared to flying solo. Take heed to the Sonex warnings of exceeding 1200lbs. The wing is just too small to handle more than 1200lbs.

[rizzz]

1200lbs?
Sonex lists the max gross at 1150lbs with a J3300, 1100lbs with the AeroVee:
http://www.sonexaircraft.com/aircraft/sonex.html

[daleandee]

I have 48 hours on my Waiex. I've flown at gross (1200lbs for my plane) only a few times with most of the weight in the passenger seats. I'll tell you, I don't like it. It really changes the way the plane handles. Just doesn't feel right, compared to flying solo. Take heed to the Sonex warnings of exceeding 1200lbs. The wing is just too small to handle more than 1200lbs.

With all due respect ... I disagree. I'm currently flying Myunn at 1250 lbs gross and while it flys differently at gross, it flys like a heavily loaded Sonex. There are a good number of Sonex aircraft with the gross set at 1250 lbs. I know of one Waiex at 1250 lbs gross and I would hope that his flight testing included a test to that weight. Perhaps your weight and balance is not optimized if you have too much weight in the seat and your CG is too far to the rear the handling could be compromised.

The wings will certainly handle the weight. More power in a steep turn is needed but with the 120 HP on tap that isn't a concern. The G loading on the wings at 1250 lbs is LESS at 4.4+/2.2- than the G loading at 950 lbs at 6.0/3.0- during aerobatics! BTW, the ASTM standard for G ratings for Light Sport Aircraft are 4.0/2.0!

Does it feel different that flying solo? Of course it does! But part of the reason for the flight test is to learn how it flys at higher weights. But if you feel more comfortable with your gross at 1200 lbs, that's exactly what you should set it at.

Respectfully,

Dale Williams
N319WF @ 6J2
Myunn - "daughter of Cleanex"
120 HP - 3.0 Corvair
Tail Wheel - Center Stick
38:18 hours - Phase One
Status - Flying
http://www.youtube.com/channel/UC49h6Qijc17_Ebfz0CbRFtg
http://websites.expercraft.com/daleandee/
http://groups.yahoo.com/group/carolinasportflyers/

[fastj22]

My W/B is such that as I approach gross, even with a full tank of gas, my CG approaches the aft limitation. With a nearly empty tank, its right on the limit. I just don't like the feel of the plane like that. Difficult to trim. Just doesn't feel right. My plane is a bit chubby. Tri-gear, paint, interior, waiex and she came it at 706. I put a li-po battery on the firewall at just 3 lbs. If I stayed with the stock lead battery, that would have added 12 lbs to the front. Beneficial in CG, detrimental in empty weight. I set gross to 1200lbs because she was so heavy empty and I wanted to maintain useful load. So I tested her at that weight.
I think if I swapped my Jab out for a Viking, I'd gain 30lbs. It would probably resolve my aft CG bias though. I may swap back to my lead battery once I convert to a tail dragger, if my CG is compromised.

[rizzz]

It seems the Viking engine has too much power for a Waiex aircraft, at least according to Jan :-).
He just posted this on his forum:

The problem associated with the Viking powered Waiex is shear power. Full left rudder is needed during the take-off run, then less after lift-off. The aircraft accelerates way past the designed in trim range, within seconds.

So, maybe someone can give helpful suggestions?

Every Viking Waiex takeoff from X-50 is more like a rocket lounge. We go from standing still, to cruising speed in seconds. (160 mph)

I don't mind the full left rudder to keep things sivilized on the ground. It is the cruise portion of the flight that has me concerned.

Seems to me the airplane was designed for a cruise speed in the 115-125 range?

At these speeds the spring loaded trim system can keep up with the airplane. Anything faster and the aircraft wants to climb like a homesick angel.

We have removed all springs in the trim system to test this. We then changed the wing incidence to help matters. We are now about to change the tail incidence, but want to do an internet quarry before attempting to do so.

The last thing I want is 20 lb of spring force on the controls to counteract the speed of the airplane


Opinions? Suggestions?

Viking

http://groups.yahoo.com/neo/groups/Viki ... sages/4743

[daleandee]

It seems the Viking engine has too much power for a Waiex aircraft, at least according to Jan :-)

My personal opinion is that Jan needs to look in the mirror if he truly wants to know the answer to this. It's amazing that so many Sonex aircraft are flying with all kinds of alternative engines without concern. Search YouTube and see Sonex with VW, Corvair, Jabiru, Rotax, and a number of turbo charged engines installed with different power outputs and rotation directions. AFAIK Casey nor Ken (both flying Sonex aircraft with Jan's conversion) never reported such a problem.

Yet by what he is saying I'm to believe that his makeover of a Honda engine with a reported 110 HP for aircraft use is causing a redesign of the air frame by needing to change wing and tail incidence?

Absolute rubbish!

Dale Williams
N319WF @ 6J2
Myunn - "daughter of Cleanex"
120 HP - 3.0 Corvair
Tail Wheel - Center Stick
52.7 hours / Status - Flying
http://www.youtube.com/channel/UC49h6Qijc17_Ebfz0CbRFtg
http://websites.expercraft.com/daleandee/
http://groups.yahoo.com/group/carolinasportflyers/

[rizzz]

And there's more coming, here's what he posted just now on this topic after Don asked what and how exactly was done to accomplish this:

Adding flaps will tip the nose down in cruise. It will also mess with the airfoil. So we tilted the entire wing instead by installing new parts and drilling the aft spar at 3.0" from the bottom skin, rather than the 3.156 called for. This helped, but is not enough.

Next we tilted the engine down 1 degree. Helped some but not enough to make any changes.

Next we are thinking about changing the angle of the V-Tail attachment, or live with aerodynamic external trim tabs.

Viking]

http://groups.yahoo.com/neo/groups/Viki ... sages/4745

(honestly, I still believe there is an issue with that company Viking Waiex and he's now just searching for excuses as to why it is not portrayed flying in all its glory all over his website and forum).

[fastj22]

I have a 120 HP Waiex that does not demonstrate the behaviors of the Viking Waiex. The only time I have any trim issue is when I'm at max Aft CG and the dial a trim hits it's stops. The loads on the stick are still slight and easily compensated for. My Waiex flys hands off at all throttle settings. Slight right rudder on climb out. Feet off rudders in cruise at 160 MPH TAS.

I can't believe he changed wing incidence and is suggesting changing tail incidence too. You can't change the tail incidence without major unapproved surgery. This is not an area to be deviating from the plans. If I were a Viking Waiex builder, I'd be looking for another engine today.

I thought he had flow the company demonstrator. It clear he is just starting to now.

[daleandee]

Funny really ...

When he was trying to sell it on Barnstormers there was no mention of any of this. I also wonder if he realizes that on his web site in his own words he says of this exact airplane, "Viking Waiex - 160 mph cruise and a BLAST to fly." That quote and the photo of the plane is here (1/2 way down the page):

http://www.vikingaircraftengines.com/sonex.htm

So he was either lying then or now ...

Dale
N319WF

[rizzz]

So he was either lying then or now ...

Both I think...