Buzzard Bombshell

[Braddock, VC]

A few years ago I bought a second hand buzard bombshell, mainly bought it to try out electric flight.

As soon as I got home I knew I'd made a mistake as the esc didn't work and the centre of gravity was literally miles out, so much so that I had to fit 700 gms of Pb up front.

It flew but it was still tail heavy so I lobbed it in the back of my workshop with a view to putting a nice little 2 stroke in it.

Fast forward to last week when I pulled it out to start work.

It's really too flimsy to pop an engine in so I started looking over how I could make it work for me.

There's a pic nearby showing a glued in hatch that covered up where the servos were, two massive metal geared chinese servos that weighed just over 100 gms.

I cut a new hatch in and made and fitted a ply mount with two corona HV digitals. Pulled the snakes out of their tube and substituted a 14 swg wire rod for the rudder and a 2mm round carbon rod as the elevator pushrod in the original tubes. The wire rod had adaptors soldered on and the CF rod had them glued on.

[Braddock, VC]

To continue, I fitted the wing and with the balance point set at 42% needed just 330 gms (the new servos are mounted at the C of G site)

Because of the flimsy front end I encapsulated the lead in gorilla glue as ther's nothing really strong enough to bolt the stuff to.

That's where I'm at at the moment waiting for the GG to set.

[Braddock, VC]

Here's the glue setting, everything is wrapped in polythene sheet and the bands are holding the battery hatch on.

I'll have to make a pattern for the windscreen which was made out of thin mylar and disappeared on the first flight I had with it.

[Braddock, VC]

Pics of the lead gorilla glued in place, tried shifting it, it's well and truly fixed.

Also access hatch for the servos, 1/8" bass gussets and held on with servo screws.

Just have to iron down the film and make the windscreen now , also some form of battery retention, stick on velcro hasn't taken to the battery.

[Braddock, VC]

Well it flew, still seems either over elevated or the c of g is too far bck. I'll try 3mm of light ply under the wing trailing edge at first to see if that sorts it.

[PatMc]

If you reduce the wing incidence you will also be reducing the motor downthrust, why not simply adjust some down on the elevator ?

[Braddock, VC]

Good point, Pat. I think I'll try some more lead in the nose as that's the easiest option even though my head tells me the c of g isn't miles out as it has a lifting tail section and my other oldies with similar arrangements fly with a c of g in excess of 50% chord from the leading edge.

I'll let you know how I get on, but it won't be for a while as the grandson is coming down for the week and all the old men up the flying site give him the heebie-jeebies.......

[PatMc]

The model you have seems to have been altered from the original to suit the builder. There are 3 versions of the BB on Outerzone, the 1940 original, a kit from the 1970's & a RCM mag's plan also from the 1970's. The original mentions the cg as being about 33% & the RCM plan shows the same position but the kit version has it at around 45%. They all have the same shorter nose length than your model seems to have & none have lifting tail section, they're all symmetrical.

Good luck with the grandson, we look after our (now) 4 1/2 year old granddaughter at least one day per week but have never yet taken her to the flying site. OTOH she's had me on a kid's slide (nearly got stuck ) & on the roundabout (dunno how I used to manage flying C/L ) a couple of times at a local park. Always knackered by the end of the day but enjoy every minute of it.

[Braddock, VC]

Yes, I noticed the variations with the CG, also the plane is built from a laser cut kit. the really annoying part has been the wood selection eg the top cabin rails are made from 3/8 triangle section that is soft as butter, some of the formers are soft 1/8 sheet and the beech engine bearers, which tend to stiffen up the structure, have been omitted.

It'll probably fly fine when I get it sorted but today I took off in flat calm and two mins into the flight half a gale blew through, high pucker factor.

Grandkids are a law unto themselves, mine is 7 going on 45 he's very technology biased and gets quite cross when I drag him outdoors, but he loves playing poosticks on the bridges over the streams in our village, as do I; it's all I have the energy for !