How much crosswind, how much fuel?

[Gunther]

Hello to all. Thank you for this wonderful forum and great discussions. I am considering the purchase of a new Sonex kit and need to make a decision re. tailwheel vs. tricycle before ordering. I live in a windy, gusty, turbulent and rugged mountainous area in BC. I plan to fly the plane from paved strips and need as much fuel as possible to account for the lack of alternate airports and refuelling facilities. I am normally comfortable with both tricycles and tailwheels but realize that the Sonex is much lighter than the old C-185s, Beavers and Otters that I grew up with. For those with actual Sonex experience, I would greatly appreciate your thoughts on the following:

1. What is your personal max 90 degree crosswind capability with either gear configuration?
2. Is the tricycle gear version significantly better for crosswinds?
3. Has anyone carried additional fuel in the wings and what method did you use, i.e., wet wings, bladders, 4" tubes, etc?
4. Any other recommendations before I order the kit?

Gunther
-old but not bold

[radfordc]

My buddy Bob and I once had to land in a 17 knot 90 degree crosswind. We both managed to not mess up! Ours are tail draggers.

A few years ago there was an outfit at Oshkosh with an aluminum tube tank that mounted in the wings of a Sonex. However, I think you would be better off with some sort of aux tank mounted in the fuselage....either fixed or removable. I saw a Sonex that had a fixed tank located behind the pilot in what is normally the baggage area. Others have used removable tanks mounted in the seat next to the pilot.

[vigilant104]

Uh, oh: taildragger vs trigear, you're going to start a fight! (I see I cross-posted with Charlie)

I live in a windy, gusty, turbulent and rugged mountainous area in BC. I plan to fly the plane from paved strips . . .

The primary operational advantage of a taildragger is on a rough field (which isn't a factor for you), and the biggest advantage of a trigear is in a crosswind (which you seem to have in abundance). Obviously, there may be other factors in play (you might just prefer the looks of a taildragger), but you've laid out conditions that would seem to favor a trigear.

I own a trigear Sonex. I don't have a lot of hours yet, but have done takeoffs and landings with up to a 12 knot crosswind component and it was comfortable. Under the heading "Crosswind Landings", the Sonex Flight Manual says (in part): " Note: In winds of 17 MPH or above, use extreme caution." I'm sure there are others here who have more experience and can offer useful opinions on crosswind capabilities.

I've never carried fuel in addition to the main tank. At the ASA fly-in at Crossville, TN this year there was one builder who had aux tanks made of aluminum tubes fitted through the lightening holes of the wing ribs. I know another builder has fashioned (and sells?) a flat upright aluminum tank that can be fitted directly behind the seat. And, I have also seen a small (5 gal?) racing-type fuel cell strapped into the passenger seat. The very rugged stock Sonex tank significantly reduces concerns about keeping fuel inside the fuselage, I'd personally want any other tank sharing the passenger compartment to be just as sturdy.

Good luck as you make your decision, let us know how it goes.

[MichaelFarley56]

Hi Gunther,

Welcome to the Sonexbuilders forums! We're glad you're here and we're happy to help you in any way possible.

You raise good questions. In general, I believe just about any tri gear airplane will be better in strong crosswinds as compared to a taildragger. Like Charlie said, the Sonex taildragger is a good crosswind airplane and I've heard many reports of pilots handling 15-18 mile per hour winds, but it can be a workout. With the tri gear, you can afford to come in fast, touch down in a small crab angle, and have the airplane automatically straighten out for you. The taildragger is the opposite...you normally are touching down close to stall speed and must be straight prior to landing.

While my Sonex time is limited, I have flown in both a tailwheel Waiex and a tri gear Waiex and can say that the trigear airplane is much better in crosswinds. It sounds like that may be a good bet for you, especially if you're operating off of mostly paved runways.

Out of curiosity, how much fuel do you want to carry? The stock airplane holds 16 gallons which can be 3-4 hours of endurance depending on power settings. If you're looking for an extra hour or two, several tank options are possible as Mark said. A removable tank in the passenger seat, fabricating an extra tank in the baggage area, or possible wing tanks are options. In general, I'd recommend some sort of fuselage tank capability just to make things easy for yourself, but that's up to you.

Regardless, best of luck and let us know what other questions you have. Welcome!

[sonex892]

Hi Gunther.

Since I'm more of a builder than a flier, I'll let the more frequent flyers answer the crosswind question

A friend of mine is installing leading edge wing tanks in his sonex. He hasn't completed them but he is serious. So serious that he sold the tank from his kit to a plans builder. I believe it can be done. There may not be any support from anyone on how to do it but it would be doable.

For extra fuel. I designed a removable tank that holds 32 litres. Combined with the standard sonex tank its 97 litres all up. 10 mins to remove and install. Takes up no baggage space. I think all up it cost maybe $200 to make. The thing I like most about it is. It's so quick to remove, I only put it in when going somewhere.

aux tank mounting.jpg (123.41 KiB) Viewed 5893 times

aux tank fitted.jpg (30.21 KiB) Viewed 5893 times

The plans I drew up are available here for all to use for free. https://groups.yahoo.com/neo/groups/son ... nex%20892/

A guy in Europe liked the idea so much he blatently copied it and sells a kit for a small fortune, 1000 euro! He will even sell you the plans for 220 euro! http://sonexauxiliarytank.wix.com/2013

Steve
Sonex 892
VH-ZSX 3300 TD

[Gunther]

Thank you for all the thoughtful replies. I will plan on purchasing a Sonex kit with tricycle gear.

Steve, I really like your auxiliary tank and thanks for the photos/plans. The fellow in Europe has paid you the ultimate compliment. Why did your friend remove and sell his nose tank? Why wouldn't he pump his wing tanks into the nose tank and keep the gravity feed to the carb?

Michael, I'm hoping to carry enough rule for six hrs with the Jab 3300 or Turbo AeroVee or ...? It will be interesting to study the turbo option if it becomes available. I am very thankful for the research and development work that Sonex is undertaking.

Gunther
-old and possibly bold

[MichaelFarley56]

Michael, I'm hoping to carry enough rule for six hrs with the Jab 3300 or Turbo AeroVee or ...?

Hi Gunther,

Thank you for the response. I'm sure others can chime in, but I believe most Jabiru 3300 owners claim a fuel burn of around 5.5(ish) gallons per hour. If you really want a 6 hour endurance plus a little extra for comfort, you're talking about 36 or so gallons. To be honest, that's quite a lot; over double the "stock" amount as I'm sure you know. I'd say you will have two choices; first would be to choose an engine that doesn't burn much fuel. Out of the three engines that Sonex supports, I'd guess the Jabiru 2200 may be your best option if you'd like to go this route. I believe owners can comfortably fly their airplane with a 4 gallon per hour fuel burn, which would then require you to have 24 gallons (a few extra wouldn't hurt). This would make the stock fuel tank plus an aux tank like Steve's a good option for you.

For your second choice, if you want to stick with the turbo AeroVee or Jabiru 3300, you're now talking a lot of fuel. I'm sure it can be done, but you may have to do some creative engineering for yourself to make things work.

In any case, pleease let us know what other options you have. Thanks!

[radfordc]

Michael, I'm hoping to carry enough rule for six hrs with the Jab 3300 or Turbo AeroVee or ...?

You must have a cast iron butt and a stainless steel bladder!

[hickej]

I installed 'tube' tanks in the leading edge to get an additional 10 gallons useful and am very happy with the results.
Pictures here: http://www.n716wx.hicke.com/index.php/u ... nkTransfer

I have some recent cross wind experience for the Waiex to report:

I haven't seen any issues with landing in high cross winds but takeoffs with the Jabiru 3300 can get 'sporty'. There are a lot of left turning forces at work with that amount of power.

I have taken off with 12-15 kt left cross winds. (I don't sweat 10kts cross and I now limit myself to 15kt. Right crosswinds are not an issue.) 15kts requires good technique and maxed out the rudder throw on my aircraft. This was from a wide paved runway (KRNM) and I did not experience a centerline excursion during the take off.

I aborted one takeoff that I thought was a 10kt left cross wind component of a 28kt wind but afterwards when I called the tower they said 28kts gusting from the north. I was taking off to the east. What I experienced was a dramatic 30 degree turn to the left on rollout. The tail wheel was skidding and would not hold centerline.

Now this part is important. If you experience an excursion, as I did, all you need to do is reduce the throttle and it comes back under control. I aborted my takeoff and taxied back to the hangar to wait for a better day to fly.

My normal technique is to use full up elevator to get maximum tail wheel effectiveness during the initial rollout until the rudder becomes effective. I neutralize the elevator as the rollout speed increases.

I currently have 130 hours on the airplane and it is a blast. It is a great weekend cross country airplane for a couple or long distance cross country for one person and all the camping gear you need. I have even figured out how to carry my folding bicycle in it! I am continually suprised at the versatility of my inexpensive LSA homebuilt.

-Jim W0162

[radfordc]

I installed 'tube' tanks in the leading edge to get an additional 10 gallons useful and am very happy with the results.
Pictures here: http://www.n716wx.hicke.com/index.php/u ... nkTransfer

How much weight did the additional tankage add?