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  • 5 months later...
Posted

does anyone operate their varieze in the 1300 pound weigh range.

Since no one has responded in five months or so, guess no one has flown or will acknowledge that they have flown around 1300 pounds. Rutan recommended that we gross at no more than 1000 or 1100 pounds, but I understand that when you build it you can make the max gross what you want.

 

I have not flown my Varieze with a C-85 anywhere near 1300 pounds.

WTJohnson

Posted

Rutan recommended that we gross at no more than 1000 or 1100 pounds...

IIRC, 1100 lb. was the MGW for the VE.

 

but I understand that when you build it you can make the max gross what you want.

Well, the builder can submit any number they want to the FAA for the airworthiness certificate, and the MGW will LEGALLY then be that number.

 

However, that says nothing about the intelligence of doing so :-). The builder can't just "MAKE" the MGW what they want, since the aircraft was designed for a certain MGW with certain safety margins. Increasing the MGW decreases the safety margin, and you don't ever want a safety margin to be less than "1". Usually, safety margins are anywhere between 1.5 and 3 on the Ultimate loads.

 

Using a MGW of 1300 for a VE (which, per the designer's recommendation, is now limited to +2.5 G's and -1.5 G's) is an increase of 18%, which could decrease the safety margin on structure to the 1.25 to 2.5 range - certainly less than the designer wanted. Not to mention miserably decreasing performance - climb rate, speed, landing distance, etc.

 

So, yes, it's LEGAL to set the MGW anything the builder wants, but it's not possible for them to MAKE the MGW anything they want :-).

Posted

IIRC, 1100 lb. was the MGW for the VE.

 

Using a MGW of 1300 for a VE (which, per the designer's recommendation, is now limited to +2.5 G's and -1.5 G's) is an increase of 18%, which could decrease the safety margin on structure to the 1.25 to 2.5 range - certainly less than the designer wanted. Not to mention miserably decreasing performance - climb rate, speed, landing distance, etc.

 

So, yes, it's LEGAL to set the MGW anything the builder wants, but it's not possible for them to MAKE the MGW anything they want :-).

............

If I recall correctly there have been several builders in the past that have set a gross weight of around 1300 lbs for their Varieze. I was hoping that someone would verify if that was really the case or not and if they actually flew at that high load. Since we have been flying Variezes for thirty years, it seems reasonable to expect some response along that line.

If I had actually loaded my Varieze to that value, I would expect there would have been an occassion where I would have landed at a high density altitude field and either made a mess at the end of the runway trying to take off or realize that I should rent a truck and drive it home.

WTJohnson

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