Buzzard Bombshell Electric Conversion and Mods

About a year and a half ago I picked up this wonderful high wing balsa old timer at a swap meet.  I did not know what it was but I'm a sucker for an inexpensive balsa old timer, especially a three channel high wing.  He wanted $25.  I offered $15.  He threw in a motor, esc, and two servos and we settled for the $25 he was asking!  I was a happy camper.

After some time and a bunch of Internet searching, I finally discovered that what I had bought was a plane called the Buzzard Bombshell.  The original design was done and built by Joe Konefes in 1940  with about a 72 inch wing span.  It was intended as a free flight as RC gear was way too expensive for most people.  This plane was designed to head up as high as so many ounces of fuel would take it and then glide for as long as possible (Joe flew his for over 49 minutes at the 1940 NATS).  To help with extended glide times they incorporated large tail surfaces that helped with lift and moved the CG to 50% or more back from the leading edge.  With the heavy motors of the time, this made for an interesting stubby nose look.

Mine was a more current and smaller version that was intended for 1/2A power sources.  It looks like it was setup for a Cox .049 judging from the mounting holes in the firewall.  Now by smaller I mean about a 45 inch wing span and still a good size plane.

Didn't realize that these cluttered photos were the only ones that I had at the time I posted this.

I'll take some better ones as soon as I get some time.

A couple of things that I really liked about this plane is that the builder did a pretty good job of construction and covering, but also, I see no oil residue and so don't think that a motor was run on this plane let alone even mounted.  I don't think it has ever been flown.

The first thing I looked at doing was to figure a motor mount

You can see here the holes for the original motor mount.  Fortunately the builder install blind nuts from the back side.  I just needed to figure out what size they are and how to go about using them.  They are oddly laid out so I can't directly use them and I'll need an adapter.

You can see the blind nuts in this photo.

I decided to use a circle of 1/8 inch plywood.  I would drill holes to line up with the engine mount holes and then drill holes to fit the electric motor mount.

I lined up the disk from the back side so that I could transfer the mounting holes from the front side.

Here is what I came up with.  I started counter sinking the holes so that I could use flat head screws so that it will fit flush against the firewall.

Here are the parts that I came up with to create my motor mount.  I ordered some aluminum stand offs from an online source and screws and washers from my local hardware store.  As I recall all of the threads turned out to be a standard 10-24.

Here is how the stand offs will fit with the electric motor x mount and the original motor mount.

This is how it would look with the longer stand offs.

Here is the new round plywood mount test fitted in place.

I needed to ream out the x mount slightly to fit the new screws.

Now the screws fit fine.

Here are the different stand offs and screws that I used.

Here is how it would look with the long stand offs.

This is how it would look with the short stand offs.  I like this look better, it puts the propeller closer to where it would have been with the originally designed gas motor.

I used different amounts of washers behind the x mount arms to set down and left thrust angles.

Here is the end result.

Now I need to start looking at where and how to mount the battery, ESC, and the two servos before I can get this thing back in the air.  These will be done in future updates.

Thanks for stopping by my blog.  Please feel free to post comments, good or bad, and be sure to come back and check for future posts.

$5 Durifly Ryan STA(M)

Ok, maybe it will not turn out to be $5, but it started that way.  I was browsing Hobby Kings bargain bin items and under the $0.99 bin I found all of the critical parts for the Durifly Ryan STA(M)!  I was really bummed to find out that the engine cowling and parts kits, while not $0.99, were out of stock, but I can live without those.  I'm not so much looking for a complete, complete deal here, I just want something that I can have fun flying, looks reasonably good, and relatively cheep.

So, here is what I ordered.  One set (yes, set, right and left) of wings, one fuselage, one cockpit, one rudder, and one stabilizer.  Each was only $0.99!  So, ok, this will not come out to a $5 build as I did have to pay shipping and HK is smart enough not to let you order too many $0.99 pieces without ordering something else (I had to split this into two orders!), so shipping cost me about $28, or about $14 each order.  But still, I'm only about $35 into a $150 plane, so far.

I did already add two 9g servos to the wings (about $4 each).  You can see them installed into the wings in these photos.

The really good stuff (besides the parts being CHEAP!) is that everything was already covered, all movable surfaces were already hinged with control horns and stoppers, and the rudder has the tail wheel installed.  All very nice indeed!

The not so good stuff, the wings came without the spare (that seemed really odd!).  So I had to make one using a lot of educated guessing (but I got it done).  The rudder was a little kinked about mid way, right where the balsa color changes.  I have no engine cowl.  I have no landing gear, wheels, or pants (I'll make a set but don't plan on making the pants), the cockpit section came without the dash decals, the manual (as sparse as it was) is no longer available (luckily someone posted photos of theirs on RCGroups), and the hardware kit is no longer available (this included all of the linkage, screws, support wires/string, wing mounting screws, and misc. hardware).  I will also have to provide two more servos for the tail surfaces, a 25Amp ESC, a 3530 1100Kv motor, and a 10x6 prop.

So far I have the wing spar made, the wing halves epoxied together, and the aileron servos installed.

This photo shows the wing spar that I cut from 1/8 inch plywood.  I measured the depth of the slot in each wing to come up with an estimate for it's length.  I measured the angle of the wing roots to come up with an approximate dihedral angle.  I carved and sanded until it fit and the two wing roots came together nice and flush.

I then put a liberal amount of 5 min. epoxy into each wing root spar opening and covered the root faces with a thing layer of epoxy.  Then I slid the left side of the spar (yes, it has sides to match the wing) into the left wing and then slid on the right wing onto the right side.  Then I taped up the bottom side good and flush (lower photo) and then pulled the top side together nice and flush and secured with tape (upper photo).  I left this to sit over night.

Here is what the parts look like so far.

Check back again and find out how this new project is coming together and as usual, thanks for stopping by my blog.

Please feel free to post comments, good or bad, and be sure to come back and check for future posts.