Heavy Hauler Wings

[lv2plyguitar 172]

I am looking for true Mark 4 wings if anyone has some for sale.  My Avid is a model C that had the Mark IV struts and other items added but my wings are still the model C. 

Thanks

Edited 12 Oct 2016 by lv2plyguitar

[1avidflyer 1983]

Do you have the heavy hauler wings now (12" rib spacing)  or the STOL wings?  (Same length, but 18" rib spacing)  I have a set of C model heavy hauler wings and they have the same .083" wall thickness spars that the Avid MK IV has.  They do have  different style fuel tanks, and no aluminum sheet covering the false ribs, but I think they would carry the same weight as the MK IV wings.  I believe the fuselage was strengthened to get to 1150 gross weight on the MK IV, not the wings. JImChuk

[lv2plyguitar 172]

The Rib spacing is 18inches with the leading edge metalized about 1/3 of the way back. Maybe that is sufficient but I don't know.

Edited 12 Oct 2016 by lv2plyguitar

[1avidflyer 1983]

The STOL wing has 18" rib spacing, and .065" wall thickness on the spars.  I think the C model had a 911 lb gross weight with these wings, and a 1050 gross weight with the heavy hauler wings.  I would suggest trying to measure the spar wall thickness.   JImChuk

[lv2plyguitar 172]

Does that gross weight of 911 change if the Mark 4 struts are added?  I am pretty sure the spar is .065.  The serial number on my plane is 365.  It seems that the 911 gross does not give much option for a two seat avid.

Plane      500  Passengers  380  Fuel    150  Total weight  1030.  So just looking at conservative numbers an Avid model C is not really a two seater plane unless you just have 10 gallons of gas.

Edited 12 Oct 2016 by lv2plyguitar

[1avidflyer 1983]

I suppose that would make it stronger.   I know Avid tested the Avid STOL wing to about 5.5 Gs with no damage done to the wing.  Just for the fun of it I punched some numbers into the calculator.  911  lbs X 5.5 = 5010 lbs.   1150 lbs  X 4 = 4600 lbs.  The FAA uses 3.8 Gs required for a normal category aircraft.   The question then is this:  is your wing as strong as the one Avid tested?  JImChuk

[lv2plyguitar 172]

So with the rotax 912 installed and 2 14 gallon fuel tanks and two people with cargo I will be running 1178 gross.  I saw those tests before.  Very impressive.

Edited 12 Oct 2016 by lv2plyguitar

[1avidflyer 1983]

As I said in my earlier post, is your wing as strong as the one Avid tested?  That is the $64,000 question.   I think in Europe aircraft builders have to set their plane upside down and do an actual load test to prove it will carry the weight it's certified for.  That is probably a better place to test it then in the air......  If I was going to fly up around 1150 GW, I would want the heavy hauler wing also.  But Avid did beef up parts on the MK IV fuselage also to go to 1150.   I'm reminded of the saying:  Better safe than sorry.   JImChuk

[EDMO 1078]

I wish someone could post up that Avid wing test page clear enough to read...

 EDMO

Edited 12 Oct 2016 by EDMO

[1avidflyer 1983]

Here you go Ed,  my copy on my PC is just a bit clearer and I was able to read it and copy it down.  JImChuk

 

The Avid Flyer is designed to withstand 3.8 G's positive, and 1.5 G's negative at 911 lbs. gross weight.  It was static tested to an ultimate load of 5.7 G's positive and 2.5 G's negative at maximum gross weight.  

Test Procedure   The wing was supported with a hydrolic jack while 2465.5 lbs. of sandbags were distributed along the wing as shown in the photograph.  The support jack was removed and the test load was left in place for 15 minutes.  The FAA requires that the load be held unsupported for at least 3 seconds.  All sandbags were removed and the spars returned straight.  No defect could be found in the wing.

[EDMO 1078]

Thanks for the post Jim - Now I have printed this out to use with my calculator and give my brain a "Happy hour" figuring how to fudge all the factors!    BTW:  Check out the plane I am posting in 'Other Planes' - really cool VTOL - just waiting for the LSA version now!  ;<)  EDMO