Engine Mount & Front Deck

The engine mount and cowling on the 303 is designed for the Rotax 277., and I was going to be using a bigger engine. I also didn't care for the front deck with the instriment pod sticking up like an after thought. all of this came down to making another engine mount and having to change the cowling.

After putting a lot of thought into this and a number of conversations with Mike makepeace I decided on what I was going to do. My cowling would be from a Fisher 202, and a friend of mine who had built a 202 loaned me his plans for the engine mount designed for the Kawasaki engine. This would enabe me to round my front deck and build in my instriment pannel.

When I recieved my 202 cowling from Fisher I used the top of the cowling to get the shape of my top deck. I used 1/8" ply for this. I glued the 1/8" pieces to 3/4" square scrap longeron materal I had and glued them to the top deck. In this photo you can see where i had cut out my instriment pannel. The top deck is not glued down at this time. When I put the fabric on the fuselage I need to extend the fabric a couple of inches on to the firewall. With the top deck on it would be very difficult to reach the bolts on the inside of the firewall for the engine mount.

With the bigger engine I decided to beef up the inside of the firewall. On the top and bottom i used 3/4" boards with a 1/8" ply sandwich on the outside. Just below the top boards that I added another 3/4" board going accross to each vertical longeron. On top of that I added I will call T-boards Which are glued on top of that. I wasn't going to add this last piece but the way everything is set up on the engine and to keep my thrust line to where it needs to be , the main part of the engine mount will go in that position. I also added 2 corner gussets on the top front and side longerons. I was told a bit of over kill.

This is the beginning of the engine mount. All this aluminum is 6061-T6. It is 2"X2" and 1/8" thick

 

This shows the completed engine mount. all the tubing is 6061-T6 and .058 thickness. The end of each tube has stiffiner sleves that are rivited in. all the bolts that go through the firewall are AN-4's

Here is the engine installed on the engine mount. To do this the fuselage was jacked up on blocks.

 

I wanted to keep the engine heat of the wood firewall. The plans don't show any protection for the firewall. I purchased a thin sheet of aluminum from Wicks aircraft. Also behind the aluminum is a piece of 1/8" fire fabric wich is good for up to 1700 degrees.

 

Here it is completed.

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