SAMS Pippit - a Design, Build and Test Thread

The current state of the nation:

Spot the (deliberate) mistake:





I never did like straight through elevators.....and now I remember why. So, here's the solution:

now that is looking a good and simple solution to a minor hic up.

Tony B wrote: now that is looking a good and simple solution to a minor hic up.

Should have designed it like that in the first place, Tony!

Of course you could have designed it so the tailplane was set back a bit so the one piece elevator was beyond the end of the fuselage.

Quorneng wrote: Of course you could have designed it so the tailplane was set back a bit so the one piece elevator was beyond the end of the fuselage.

We did consider that Q, here's an excerpt from an email I sent to Kev yesterday morning:

"....Possible solutions follow:

- Add noseweight so that down elevator is not required. Perhaps not!

- Cut fuselage to suit - looks ugly, it would need a re-design of the tail skid, but it would work.

- Mount tailplane 15mm further back - it wouldn't be a Pippit then.

- Split the elevators and extend the bottom of the fin - preferred......"

The aim was to make an RC conversion of the basic model with the minimum of change. The split elevator keeps the original shape with only small changes to the structure and outline.

With the aim in mind, if you can think of a better way of doing it that would be easy to produce with parts that are readily available, I'd be delighted to hear it.

Fair enough for wanting to keep the original construction for the RC conversion.

The issue of a one piece elevator reminds me of the tailplane of the Slingsby T49 Capstan .
Unusually for a full size glider it was mounted behind the swept fin but under the broad rudder and fixed to the top of the fuselage longerons. Both the underside of the fin and the rear fuselage only had to be slightly cut away to allow elevator movement. It looked pretty neat.

Thanks for the kind words John.

The Pippit motor and gear box comes from a ParkZone Mustang BNF model that Inwoods were selling off a few years ago for about £45 each. The RC module from he Mustang is in the RC Long John. Individual units can be obtained as spares and similar ParkZone models can be found on ebay. However, Kev (plane krazy) of SAMS Models is now selling them as a unit with prop, LiPo and flight profiler for £44.95. The complete unit weigh around 15 gms and will power a model of up to about 30" span.

It's the last item on this page (scroll to the bottom):

www.samsmodels.com/acatalog/Section_F._M...__Co2__Electric.html

There's a similar unit in my BE2c.

Two steps forward and one step back....or is it the other way round? Anyway, while looking at the fus a couple of days ago with a view to adding the radio bay and a few crosspieces, it rapidly became apparent that it had dried out of square. I pondered the prob for a couple of days, but there was no option but to cut the thing back to the two basic sides and start again. I'd used balsa cement, so pulling it apart was a simple mater of melting the glue with cellulose thinners.

Sooooooo, this morning she looked like thsi:



At lunch like this:



and this afternoon, like this:





onward and upward, that's what I say!

It's time to do a bit more to this one. Peterborough Model Club have a fly-In for Club Members on Ferry Meadows on Christmas Sunday. That would be a good day for a first flight, so I now have incentive to achieve a building deadline!

The tailplane, fin and wings have been sanded and the latter joined:




No other pics yet, but that will change as the build progresses.

That looks a lot of dihedral Andy or is it an optical illusion ?

The model has a lot of dihedral to give it stability in windy conditions....the idea worked as the prototype was successfully trimmed in a 10 -15 kt wind.

I covered the tailplane and fin a couple of weeks ago, and today's work has included shaping and sanding the elevators and rudder and adding the motor mount to the fus:

Very neat but what power system are you going to use and how will you mount it ?

one tenor wrote: Very neat but what power system are you going to use and how will you mount it ?

Well John, I used to have one of these:



Which I've turned into this:



....and here's a mock-up of how it'll look in the Pippit - RC:





The motor is the same as that in the prototype Pippit, so it'll be mounted in the same way with 2mm self tapping screws.

Fuselage is now just about complete - just the tailskid to fit and a bit of sanding and it'll be ready to cover: