Monday 29 November 2010

Construction information about the Baby Wingwalkers

However great the planes look, the model wingwalkers always steal the show.  We are often asked where people can buy them and the answer is "you can't" because they have been individually hand made.

The arms and legs are carved from balsa.  Richard tried making moulds but found they were too heavy if they were moulded.  The bodies are made from a two-piece fibreglass mould, using lightweight cloth,  The bodies are slightly larger than the real wingwalkers because there has to be room for the 2.4 GHz receiver inside which powers 5 mini servos that move the arms, legs and heads.

Each head is individual and based on one of the real wingwalkers from the team, currently we have Sarah and Danielle.  The heads are carved from plastic wood, a two-piece silicone mould is made and filled with fibreglass.  Richard tried a slush mould head but it was too brittle and he couldn't get a consistent thickness.  After all the trials he now has a box full of heads!

 Probably the most time consuming job is stitching the hair into place.  Richard made thousands of 1mm holes in the heads and each hole had 6 strands of hair hooked through. It took 3 long days per head, working 15 hour days.  Danielle's hair took slightly longer because 3 colours were used to match her hair colour.  The hair on the models is slightly longer than the real wingwalkers' hair because it's real hair so it is proportionally thicker and so not as supple.  When it's longer it holds its shape better because of the extra weight.

The costumes are also hand made, using pictures of the real ones to work from.  Because the fabric pieces were so small the patterns were turned into computer drawings and then laser cut to get them as accurate as possible.  Then they were sewed on a standard sewing machine. Lycra is not easy to work with at the best of times because it stretches, but with such small pieces it was very difficult and there was some unpicking and starting again.

The boots and hands are made in the same way as the head, carved and then a silicone mould made. The boots aren't identical to the full size ones because they have to be smaller so they can be taken off to put the clothes on.  Both the boots and hands are slush moulded with expandable foam put in to make them rigid.  The boots and legs need to be kept as light as possible to reduce the load on the arms and legs when they are lifted.  They are attached to the arms and legs with a dowel.

Finally, each model has a watch which is a commercially available 1/4 scale one that has been repainted orange.

Photos copyright of Chris Bowler.

Sunday 21 November 2010

Modifications from the Balsa USA Stearman kit

The Stearmans are built from Balsa USA kits but have had some modifications to make them lighter and more detailed.

Holes have been laser cut in the fuselage formers, the tailplane, fin and wing wherever possible.  This reduces the weight which is especially important in these models because the rig and wingwalker add quite a lot of weight. 

To get the best performance we need to keep the weight as low as we can, whilst not compromising the strength of the structure.

The tailplane was made removable to make the planes easier to transport.  Both planes are transported in one van so they take up less space with the tailplanes off. Carbon fibre tubes are used to join the tailplane.  Elevator servos are in each half of tailplane

The Breitling team use Super Stearmans which have more flying wires than the Stearman so extra mounting points were fitted to attach the additional flying wires.  Hard mounting points also had to be added to attach the wingwalker's rig.

The spar size in the wing was reduced by half and webbing used to make the wing as light and strong as possible. The square aluminium tubes in the kit were replaced with round ones and are not glued in.  That way they are easy to remove so make transportation easier.

To match the full size planes that the models are based on top ailerons have been fitted and the bottom ailerons reduced slightly.  There are several configurations of top ailerons across all 4 planes that are either finished or in construction.  Some top ailerons are nearly the same size as the bottome ones and others are smaller. These reflect the full size configurations.

The nose has been shortened so the prop hub is in the correct line. A completely new cowl was made and starts from the cabane struts. On the full size the cowling was a modified Beech.  New wheel spats were made to the correct shape and a new spinner was made.  The spinner on the Super Stearman is a Harvard.

Tuesday 16 November 2010

A pilot's impression of flying a Stearman as part of the Baby Breitling Wingwalking Team

After a season of flying one of the Stearmans here are some of the impressions from one of the pilots, Steve.

When we fly in formation Richard, who is the first pilot, controls the display and the speed and it's up to me as the second pilot to make the adjustments in position so that we stay in formation.  Each display is different because of the site and the weather conditions so Richard is making adjustments to keep the display within the right area and I make adjustments to stay in formation with him.

I use the rudder a lot to slip the plane into position.  I can't use the ailerons and bank because people will see that the wings are different to the other aircraft and so it spoils the look of the display.

The point at each end of the circuit is the most critical part when you're flying in formation because both pilots may be going into the turn at different speeds which then means we will enter the next manoeuvre at different speeds. If you don't get the formation right at the end then the manouevres in the middle will never be correct.

The Stearman is a simple aircraft compared to some of the planes I fly.  It doesn't have retracts or flaps but it has its own complication in that the wingwalkers make it top heavy so you have to allow for that.  The wheels have a narrow track so, as we have experienced at most shows this year, it is difficult to land in a crosswind.

My favourite part of the display visually is when we put the smoke on - especially when there's a blue sky too.  

My favourite manouevre is the Superman at the end.  It's a straightforward manouevre as it's simply flying inverted but it shows the wingwalker off perfectly.  I've got used to not watching the wingwalker and just watching the plane, but in the Superman I look at the wingwalker as well to help me position the aircraft.

As I come in quite low and slow it's not a place where you want the engine to stop!

Photos copyright Neil Hutchinson & Chris Bowler and may not be used without their permission.

Tuesday 2 November 2010

Baby Breitling Wingwalkers at Gaydon Motor Museum, October 2010

Model aircraft isn't the first thing you would expect to find at a motor museum. But this is the third year that the Large Model Association has put on a static display of models at Gaydon and each year it is popular with both the modellers and visitors.  Just like Yeovilton, there is the chance to look round the museum as well so there is a double attraction.

After the previous day of rain it was nice to be able to put the Stearmans together in the warm and dry and know there was going to be no mad dash for rain covers.  It was a good chance to catch up with the other modellers without the usual rush of a show with one eye on the schedule.

One trick we like to play is to be standing away from the models amongst the rest of the crowd and then gently turn the wingwalkers' heads.  Because it's such a slight movement people aren't sure whether they've seen a movement or whether they imagined it.  Then a little arm waving and leg bending and they can see the wingwalker is moving but they're not quite sure how.  So, if you're at one of our shows you'll know to look out for the person with the transmitter who's standing behind you.

Wandering round the rooms, as well as familiar models you also get a preview of the partly built models that will be on the show scene in all their glory next year or the year after.  One of the modellers, Chris Bates, has put together a slideshow of the models that were there which shows the huge variety.