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Simon's 'Petiterina'


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Peter

If I built it the object would be to see how little need be anything other than Depron.

My guess is it could follow the smaller one pretty closely with balsa only being used for the spar flanges and some local reinforcing around the retracts along with a ply motor mount.

Still thinking!

Colin

I think my full size flying days are long over. The thrill of relying on your own skill and judgement to keep yourself alive no longer seems quite so attractive as it did when I was in my twenties! wink 2

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When I was flying C152s etc. there were occasions when the need to think in multiple dimensions and work the radio as well (!) had my shirt sticking to my back. That was then I realised that by comparison with fast jet pilots I would never achieve higher than the level of a Neanderthal! That applies to most things that I do, but as my aspirations always exceed my capability it means that I always have something left to aim for. I just never get there.

There's no question that you can build the bigger Ballerina using your super light engineering approach and fly it with a low power requirement. With the Marauder I want to work as close as I can to Peter's structural design with straightforward Depron substitution where practical for simplicity. I'm looking for a realistic weight reduction but not super lightness, with equal practical robustness as a regular weekend flyer. For this reason it will be covered with 17gm glass cloth, using Ezekote and then painted. Hopefully, it will work.

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Colin

A bit like when I did my gliding Silver C 'distance' flight. Setting out for an unknown destination at least 50 k away with only the unpredictable UK summer weather to keep you up.

I did cross my mind this was not the safest thing in the world to do but of course I was sure I was at least as good as the other glider pilots in the club. The confidence of youth.

A RC electric motor glider is so much less stressful! wink 2

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Simon, although I've done a few flights on and off in gliders, I never took any instruction formally. I remember a flight at Bristol Nymphsfield about 1970(?), an aero-tow in a Slingsby Capstan behind a Tiger Moth flown by an ex Spitfire pilot with a handlebar moustache. About 1,000 ft. up I watched in horror as a cloud of black smoke came out of the Tiger and the prop juddered to a stop. The plane waggled its' wings, dropped the tow and did a sharp diving turn back to the strip, while we sat there looking out at the Bristol Channel. I was with the CFI, Chalky White, another ex RAF type, who was in total command of the situation, he aborted our trip and took us back serenely to land, where the Tiger sat forlornly. I went back a few years later and a Bellanca Scout was being used as a tow-plane, the Tiger had been destroyed in an arson attack on a hangar some time before. Very sad. Respect to you for getting , your Silver "C", quite an achievement and something to treasure.

Peter, I was born in 1946 and missed National Service by a few years, which to be honest I regret. At school I never really knew what I wanted to do except for an enthusiasm to fly in the RAF. Although in more recent years, modern medicine enabled me to correct my eye-sight, I was originally very short-sighted and wore thick specs. (See the photo on my post headers, taken in 1963 sat on my 1960 Norton Jubilee). In those days there was no chance of flying on active service with eyes like that, so I didn't sign up. Although I've had a reasonably successful career, more by luck than judgement, I often think that I should have joined up even though I couldn't have been aircrew. I envy your experiences, you must have great memories and clearly still have your enthusiasm. I've certainly never lost mine.

In the month since I kicked off the Super Marauder, I've been away from home for 16 days and now again tonight and tomorrow night, but I'm back home on Friday and will get on with it then. It's going together quite quickly, it's actually had very little time devoted to it yet. From this weekend things are back to normal. I did the XB42 in four build weeks from completing the drawings, so this one won't take too long.

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Hi Colin

I wanted tp be pilot but eyesight and an amazingly patchy education put a stop to that and I am not sorry. I am really someone who likes working with my hands.

Like all things the air force had good and bad times but looking back I would not change anything.

Lots to look back on with pleasure, lots of fascinating things.

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Still playing with my Petiterina.

With its considerable power to weight and low wing loading it not surprisingly displays a considerable trim (and speed!) change from a slow glide to full power.

Down thrust is the normal way of overcoming this but with a close fitting spinner any later adjustment is not really possible and anyway I am not keen on the 'down thrust' look!

This morning I spent some time counting the trim beeps when adjusting from a steady cruise position (the default at switch on) to achieve the best glide and reasonably flat flight at full power.

Using the DX6i monitor function I was then able to set a throttle/elevator mix to give the same elevator movement as the manual trim. From the cruise position it needed 10% up at no throttle to 10% down at full. Just to be safe the mix can be inhibited with the gear switch.

Just got back from a test (nice still conditions but with light rain!) and it works remarkably well.

Probably the most impressive feature is the incredibly slow yet stable glide that is achieved just by closing the throttle! wink 2

The CofG is at 28%.

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Still thinking about a Depron Ballerina with retracts so I thought I would draw an underside view to see what it would look like rather than showing the construction detail.

One up, one down although I doubt I could really get away with such a tight fit in the wheel wells!

Underside1

It comes out with a surprisingly narrow track but at least that puts the U/C mounting not too far out thus limiting the load on the wing.

As it would be frown from grass - no undercarriage doors. wink 2

I will have to decide "go/no go" soon.

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  • 1 month later...

The Petiterina is still being flown fairly regularly as it is such a docile thing to fly but with bags of oomph! It makes an intriguing combination.

Unless flown at full power all the time (actually almost impossible to do!) it has a substantial endurance allowing multiple 'normal' flights on the same battery.

With is remarkably slow gliding speed coupled with a low sink rate I am pretty sure it will thermal quite nicely. Bring on the summer!

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  • 2 weeks later...

I had intended to video a Petiterina flight but the "hat cam" was not adjusted properly so most of it was lost but I did manage to record a few bits of the landings.

Despite the 'lumpy' grass virtually brushing the underside of the wing with its slow gliding speed and soft springy undercarriage it just 'settles down' nicely. wink 2
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  • 2 months later...

For experience I [rinted a more or less scale 9 cylinder radial based on the P&W Junior. A 9 cylinder radial hopefully has a crankcase big enough to put the electric motor completely inside it.

Front

The crankcase is completely hollow.

Rear

And the whole thing is sized to encompass a 28 mm out runner with a bit of clearance.

28mmmotor

The motor is mounted such the prop driver just sticks out the front.

Propdriver

It set up on my test stand.

<iframe width="450" height="253" src="https://www.youtube.com/embed/Tq4HLp-YcvA" frameborder="0" allowfullscreen></iframe>

The Emax 2822 is turning a 9x6 which is about the scale diameter. It us also exactly the same set up I used on the Petitierina so that had its nose cut back and the radial installed.wink 2

Radial 4

It gives it a bit of an agricultural air!

Radial 2

As the bulkhead is unchanged the radial ends up a bit high on the fuselage but at least the prop clearance has been maintained.

It has added a bit of weight, 16 g taken away and 30 added which has resulted in the CofG moving forward by 1 mm.

Not intended to be a 'bull' paint job as it is not a scale plane to start with however if you really must have a detailed engine. and you have the time. 3D printing does allow it to be made to exactly the size you want.

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The installation of the radial on the Petiterina was a bit of a 'lash up' so with a couple of days free I decided to engineer something a bit better.

The firewall was removed and the fuselage cut back to the first Depron former.

New radial 1

The new circular fire wall in place.

New radial 2

The planking completed. The firewall is 3 mm further back to restore the original CofG.

New radial 3

The 9 cylinder radial re installed.

New rad cplt 1

A side view of the new nose profile..

New rad cplt 3

Nice today (wed) so it got a test flight. After a good 15 minutes with many rolls, loops, take offs and landings I stopped simply because I just didn't want to risk breaking it doing something silly.wink 2

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