So we want light weight side housings but also a tough wear surface,
 right? Can we band saw all but about 1/4" of the factory iron side
 housings away, and then use most of the Racing Beat aluminum housing
 mated to it? What kind of gasket or seal would be required between
 the iron and aluminum?


 Happy New Year!

 Matt-

 I have been doing that for my single rotor work since about 10years ago.
 The
 prove of principle engine is still running strong with this arrangement.
 The problem area I encountered is around the stationary gear area whrere
 the
 CI and AL need to be connected (first picture). It was only possible with a
 lot of JB Weld, in a way I would not want to have in a flying engine.
 The flying engine side housing has a CI running surface insert(second
 picture).
 I do not have a design for the center housing nor for a power-take-off side
 housing.

 Happy and prosperous New Year.

 Richard Sohn
 N2071U

 Matt, It is possible to design a two piece housing in CAD which makes open
 casting patterns, or CNC parts since no core pattern is needed. The only
 chalanging part is keeping the water amd oil separated at the stationary
 gear/main bearing area. There is room for "O" ring seals (actually 2 seals)
 and the clamping force can be the bolts thru the stationary gear threaded
 into the rotor face side. The bolts can have intermediate bolts added to
 double up the number. The center housing has no stationary gear or bolts and
 needs a different approach. I have designed it with one side fitting into
 the other like a piston in an air cylinder with radial "O" rings. In all
 housings the outer edge is sealed by "O" rings which follow the shape of the
 parts around the ports. Originally I intended to use nickel iron wear
 surfaces and magnesium for the remainder of the housing. I was tying to
 avoid detonation gun coating of the aluminum wear surface. Furthur research
 indicates that a high silicon content aluminum alloy designed for automotive
 pistons mau surve as its own wear surface. I am looking at 398 alloy with 17
 %silicon. Remember the vega that chevrolet built or briggs and stratton lawn
 mower engines. These engines have more oiling due to splash than the rotary
 apex seals and will require 2 stroke oil in the fuel for the apex seals as
 is current practice. IMHO all the side seals which contact the aluminum
 side housings are either running in oil from the flodded rotor or are
 exposed to the same fuel/oil mix as the apex seals. The aluminum housings
 can be furthur lightened by eliminating the porting and using a periphial
 port arangement. Personally I have drastically redesigned the ports to get
 away from the relatively sharp entry into the rotor housing, and added two
 more ports in the center housing for a total of 8 for a two rotor engine.
 The aluminum side housings will likely be less efficient than the iron
 housings due to their ability to conduct heat away faster than an iron
 housing. This will also influence heat load on the water side of the cooling
 system. If you can tolerate the weight the iron facings seem to be the best
 arrangement. Paul has posted renderings of this on the newsletter. My take
 on it is that it can't be a thin flat plate because the stationary gear
 bolts need something to thread into to clamp the centers together. You could
 mount iron housings to the faceplate of a lathe and turn off most of the
 housing leaving a raised center area which contains the stationary gear
 bolts. Personally I would leave the entire face intact including dowel pin
 and tension bolt holes etc to ensure the gear and bearing are properly
 located. I realize this is not the insert wear plate others are using which
 is lighter. Also getting one of those slick PSRU plate/motor mount plates
 from Jeff will take the prop torque off the engine case which has resulted
 in cracking around the dowel pins on some modified housings. This torque is
 2.85 times engine torque due to the gearbox. That leaves only reaction
 torque from the accessory end rotor on the dowel pins.If you could
 adequately protect the running surface of your doner housing you might avoid
 having to lapp the part, or at least reduce the price. If you intend to lapp
 the parts anyway then reject housings (warped or worn) should be
 available, however these parts are all nitrided since 1994, and some before
 that, and would need retreatment of the surface. It would require two center
 housings to make parts which can nest into one another for a radial "O" ring
 seal in the center.The available weight reduction doesn't seem to merrit the
 cost and complexity for the center housing. Most interest is for a light
 weight one rotor which doesn't have a center housing and there are still
 two bearing mounts to clamp the center area together even if the gear is
 turned off one of them. There are also some other aluminum alloys which may
 need no surface treatment. The first one I found was used by BMW and had
 zirconium in it. This alloy has to be pressure cast where the 398 can be
 gravity cast. Someone needed my computer more than me so I lost my CAD
 software last year and my project is delayed. I started this month to
 recreate the whole thing in Rhino which I had on an ancient hard drive. It
 took forever to get the shetches part of the drawings done in autocad14
 separated from the 3D solids and imported into Rhino. I did most of a
 dunafocal engine mount front housing yesterday and as I try to remember how
 to work Rhino the speed will increase eventually. When I get done in a few
 months The solid models will be available free to anyone, with stl models, G
 code etc included. I am doing cast parts but the G-code of finished parts
 would permit CNC machining directly from billets.

 george grimes

 George, you need paragraphs :)

 Paul Lamar



Matt and George

kinda like this


jeff