H5606
Posts: 82
Joined: 7/17/2006
From: , MD, USA
Status: offline
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Dave,
Thanks and it's nice to get confirmation on my memory about the C.G.
I tried to find the formers for the cowl that I salvaged from the wreckage of my Hots and was thinking about scanning them in to post but I'd have to dig too hard... Don't know if that would work anyway.
How I constructed my Hots cowling: Remove the engine and mount and trace a "footprint" of the front end -- i.e. firewall and perimeter sheeting onto a sheet of paper. Do the same with the spinner backplate and also mark the center. The firewall area tracing should look like the profile of a house with the apex lopped off. To allow for sheeting thickness, redraw the front end "footprint" inside the first by 3/32" -- this is the firewall-end former pattern. Make the same, proportionately smaller drawing inside the spinner backplate circle with the corners clearing by 3/32" -- this is the spinner-end former pattern. Adhere the templates to 1/16" ply and cut out using favorite tool(s). Cut a round or square hole to clear the engine mount in the firewall-end former. Enlarge the hole in the spinner former so that it just presses on the drive washer of the engine. Now, tack glue the firewall former to the firewall, install engine and mount, and press the spinner-end former on the drive washer. Hack out a 1/32~1/16" thick piece of something with a 1/4" hole to use as a spacer between the spinner backplate and spinner-end former. Now, just sheet the bottom and sides with 3/32" balsa sheeting. At this point, the incomplete cowling can be pulled off the airplane to complete the sheeting process. Lastly, cut and fit cowl to clear engine. Finished using epoxy finishing resin then sanded and painted with Formula-U. On the first cowling I made I tried to disguise the squareness with those cheesy-looking cheeks. Later, I leaned my engine installation over 45 degrees, built a new cowl and added balsa to all sides and sanded/shaped to fair in nicely with the spinner backplate. Never got pictures of it.
Another Dave
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All Forums >> RC Airplanes >> Sport Flying >> RE: Another Hots! 
RE: Another Hots! - 
. I'd like to think I know better now not to use that kind of rotating mass on the end of the poor engine! The airplane had a tendency to "hunt in pitch" or porpoise at high speed that I thought was caused by the short tail moment. Much later, after I modified the engine installation and added a new cowling, I removed all the nose weight and ended up with the C.G. at 1/8-1/4" behind the spar. This is where the airplane really grooved! I think the pitch hunting problem was due to sloppy elevator linkage issues. Here are pictures of my Hots and a couple others before I learned how to carve and shape balsa and design 
. I had no right thrust in mine. Choose light wood for the tail. Keep the pushrods straight, and hinge-lines tight. 
