An email from Don Schumann who is converting retractable wings to fixed gear.

  Jerry,
        Read your articles, nice job.
        I'll be attempting your layup technique soon.
Met you at Oshkosh last year but with 500,000+ in attendance
I don't expect you to remember me.
Anyway,  to cut to the chase....

        I am currently assembling/converting a set of RG Wheeler wings and had a question regarding the dense foam material used on the aircraft. What type of material is it?  I looked through the aircraft spruce catalog and found several choices, but rather than guess I was hoping that you would know?  I need small amounts of additional foam material because I am not assembling the wings as RG but converting them to fixed gear.
    I have a second set of fixed gear wings that I can use to compare and convert measurements from.  The wings are virtually identical except for minor differences.  (No jokes about building a bi-plane please).

        A second question I would like to pose is the choice of fuel tank arrangement.  Larry Olsen says that converting a dual tank arrangement to "large" single tank(one on each side) greatly simplifies building (which I cann't deny), the engineer in me says thats an awful lot of weight that can slosh back and forth over a large moment arm and I have some concern regarding weight shift inflight.   Soo... I've been considering conversion to the extended tank configuration(which takes
the middle road).... any comments?  Extended tank is plenty of fuel isn't it?  (I'm leaning toward an Lyc IO540)

Thanks in advance,
Don Schumann

xanth01@ibm.net    -or-     dschumann@lucent.com
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My answer to Don.

Hi Don,

    Although I don't remember meeting you at Oshkosh, I wish I could. I have enjoyed getting acquainted with a lot of wonderful people as a result of the Express project. I will look forward to seeing you again someday.

    In answer to your questions:
    The light weight foam is a (poly)urethane 4 lb density material.  The heavier, or dense, foam is a 40# (poly)urethane material. I checked the Aircraft Spruce cataloge and neither one is listed.  You should be able to purchase what you need from Larry at Express Aircraft in Olympia, WA.  360-352-3554. If I knew where you live, I could suggest that you contact one of our builders near you and get some leftover foam stock.
 
Suggestion: Add you name, address and phone number as a "signature file" to your email as I do. Or, email the information to me so I can add it to my address book. Thanks.

    The choice of fuel tanks for me was very simple; 1 tank each side, one fill hole, one gauge, one vent, etc.. I have the 94 gallon capacity tanks with 92 useable. I have the TCM  I0360 (210 hp) engine and burn 8 to 9 gph at cruise with a 1000# useful load. Range is over 2000 miles without refueling.
    Sloshing is eliminated by putting a flapper valve on the center rib in the wing. This will limit the back flow of fuel into the outer fuel bay. When filling and in use, the fuel will always flow inboard to the pickup point. For the hinge I used the aluminum (aileron) hinge material and a piece of electronic circuit board material (epoxy/fiberglass) for the flap. Stainless steel rivets or fasteners are a good idea for installation of these parts in the fuel bay.  Stainless steel hinge would be a good idea if it is available. Flapper size: about 1-1/2" high by 3" long and close to the bottom wing surface covering a hole about 1" x 2-1/2". Note: Glasair uses stainless steel flapper valves in there fuel bays. That is where I got the idea for my Express when considering the fuel arrangement. Very important: Add a vent hole and a water drain hole about the size of your finger at the upper and lower edge of the wing spar cap on the center fuel tank rib.
 
    Remember, In a coordinated turn the fuel will stay in place, even in a steep turn.  Only in un-coordinated attitudes will the fuel move outboard or inboard.
 
    With regards to "plenty of fuel?" How much is enough when you really need it? If you have the capacity, you have a choice. I remember flying many times to Seattle in my Skylane or my 206 and having to stop for fuel on the way to be able to complete the trip or just to be safe. The flight I just made to Arlington, Wa. for the EAA flyin was done non stop in just over 4 hrs (I have 10 hrs of fuel on board) and, had I not given a ride to Shane Mahoney, I could easily have returned to home base without adding more fuel. Fuel is like altitude; how much is enough for safe flight?  Both are important safety factors to me.
 
    If you are planning to put in the I0540 engine, you will need more fuel because of the higher burn rate. My opinion; Use the long range tank option and then carry as much fuel as you decide necessary for safe flight.

    A question?  What landing gear legs do you have at this time? Are they steel or fiberglass (Wheeler)? Have you considered the light weight fiberglass gear legs and bracket assembly from Larrry at Express Aircraft ? Express Aircraft Company, [Official Home Page]  What do you plan to use?

    Good luck witht the wing  projects.  Let me know if I can help again.

    Best regards,
    Jerry Sjostrand