Anderson Ed wrote:
Hi Alan,
Met you and your gracious spouse at a RV flyin at Fredrick Maryland a
few years ago. But regarding the weight of my RV a few details may
help. First, as we all know the weight of the rotary engine is
certainly in the ball park of a 320-360. However, aircraft weight
involves, as you know, many other components. Here is my accounting of
the additional weight of items you would not normally find on typical
lycoming installation.
Extra 25Ah battery, battery Box, Contactor and wiring = 25 lbs
Two 3 1/4" dia 36" long mufflers and brackets = 18 lbs
Homemade intake manifold (machined out of two 1 1/2" slabs of alunumin)
Weight in excess of stock manifold = 8 lbs
Extra thick walls on exhaust headers(.062)(extra weight)= 3 lbs
Water heater for Cabin heat =3 lbs
Bracket, shaft and Pulley for driving aircraft Vacuum pump (does not
included pump) = 3 lbs
Stainless steel coolant hose and fittings AN-16 = 8 lbs
Water Radiators and brackets (total) = 9 lbs
Coolant Weight ( 2 1/2 gallons @ 8 lbs gallon) = 20lbs
Additional instrument Gauges (water tem/pressure) = 1 lbs
Aluminum Header Tank = 3 lbs
======
101 lbs
Throw in two landing lights, heated pitot, more electrical switches and
circuit breakers (like would you believe 50! Yep I counted them -
surprised me also)foam insulation, more electrical wiring and the
general inefficiencies of a first time builder and I think I could find
another 25 lbs in there somewhere.
As I have often said an ounce here and an ounce there and pretty soon it
adds to 1170 lbs. So certainly I don' attribute all the increase on the
Wankel installation. There is no reason that done right it would not
coming in at less and certainly no more than a lycoming.
I intend to undertake some weight reduction efforts. For instance I
found a battery comparable to the 25AH RG that weighs 7 lbs less and
have replaced one of the 25AH RGs. Also, the massive intake manifold is
scheduled to be replace by a tube type or composit and then I can use
the old manifold as a boat anchor.
So Alan, that is how I managed to get my bird to weight 1170 lbs empty.
So while there is no doubt my baby has more baby fat than I would like,
I have seen several Lycoming powered RV-6A come in at over my weight and
indeed af few over 1200 lbs empty weight. In any case, I am going to
work on bring the weight down by at least 50-70 lbs.
If I were installing a 13B from scratch now that I have the experience
there are a number of things I would do to keep the weight down.
Ed Anderson
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